Comparison by Spurts

Unread postPosted: 19 Feb 2020, 15:07
by sprstdlyscottsmn
Hey all, my OG thread on this ended up locked. I wanted to say that I made a few updates to the missiles and I did something I normally don't do... I lifted the CFT AA stores carriage limit on the F-15SA. While I have no evidence of this actually happening the F-15SA/QA/EX seem to put an emphasis on AA work more than the Mudhen did, and as such I am making the assumption that the stores envelope was expanded. I realized I had done something similar with the Su-35S in removing it's max G shift through the trans-sonic and into the super sonic. No evidence, I am just assuming new improved versions also improve known weaknesses where reasonable.

Re: Comparison by Spurts

Unread postPosted: 20 Feb 2020, 18:52
by sprstdlyscottsmn
Here is the comparison currently. I am working on the F-16 model now.

Strike Fighters 2025_4.pdf
(1.74 MiB) Downloaded 1013 times

Re: Comparison by Spurts

Unread postPosted: 20 Feb 2020, 19:40
by garrya
sprstdlyscottsmn wrote:Hey all, my OG thread on this ended up locked. I wanted to say that I made a few updates to the missiles and I did something I normally don't do... I lifted the CFT AA stores carriage limit on the F-15SA. While I have no evidence of this actually happening the F-15SA/QA/EX seem to put an emphasis on AA work more than the Mudhen did, and as such I am making the assumption that the stores envelope was expanded. I realized I had done something similar with the Su-35S in removing it's max G shift through the trans-sonic and into the super sonic. No evidence, I am just assuming new improved versions also improve known weaknesses where reasonable.

Why did it get locked, it is the best thread :(

Re: Comparison by Spurts

Unread postPosted: 20 Feb 2020, 19:43
by garrya
sprstdlyscottsmn wrote:Here is the comparison currently. I am working on the F-16 model now.

Strike Fighters 2025_4.pdf

Iam very grateful that you took the time in your day to bring us this master piece free of charge

Re: Comparison by Spurts

Unread postPosted: 21 Feb 2020, 08:10
by eloise
sprstdlyscottsmn wrote:Here is the comparison currently. I am working on the F-16 model now.

The attachment Strike Fighters 2025_4.pdf is no longer available

You are the best.
In the spot area section, do you consider the top view of the aircraft? I think the frontal view is better for comparison because aircraft are rarely viewed from the top
spot.PNG

and what is DPS? is it degree per second? why some missile turn better at longer distance?
dps.PNG

and I don't think SLAM-ER should have smaller RCS than SPEAR, they have similar shape and the later is a fraction the size of the former. SPEAR is in fact smaller than Meteor
Capture.PNG

231495_800.jpg

s_IMG4094-MBDA-Meteor-and-Spear-missiles.jpg

Re: Comparison by Spurts

Unread postPosted: 21 Feb 2020, 13:57
by sprstdlyscottsmn
eloise wrote:In the spot area section, do you consider the top view of the aircraft? I think the frontal view is better for comparison because aircraft are rarely viewed from the top

when looking at the size of an aircraft the critical issues are length and width. "height" is predominantly a factor of thin little vertical tails and landing gear length.

eloise wrote:and what is DPS? is it degree per second? why some missile turn better at longer distance?

Yes degrees per second. Some missiles appear to turn better at the end of their flight because they are now in denser air and/or are flying slower. A missile flying at twice it's corner velocity is not going to be able to turn as quickly at the same G.

eloise wrote:and I don't think SLAM-ER should have smaller RCS than SPEAR, they have similar shape and the later is a fraction the size of the former. SPEAR is in fact smaller than Meteor

Round nose with exposed seeker vs faceted nose. It boiled down to that.

Re: Comparison by Spurts

Unread postPosted: 21 Feb 2020, 18:43
by eloise
sprstdlyscottsmn wrote:when looking at the size of an aircraft the critical issues are length and width. "height" is predominantly a factor of thin little vertical tails and landing gear length.

I think length and width can be deceiving because they could have different wing shape and vastly different area
781CCA68-F06C-4390-80BB-6C93A1C59BC1.jpeg

sprstdlyscottsmn wrote:Round nose with exposed seeker vs faceted nose. It boiled down to that.

But SPEAR is very small, smaller than a short range air to air missile. And a short range air to air missile only has RCS about 0.03 m2 frontally
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And SPEAR uses 3 tail fins instead of 4 tail fins like SLAM-ER. 4 fins design make right angle corners
0136BF52-A1CC-44C3-8215-5B10E5A904C2.jpeg

Re: Comparison by Spurts

Unread postPosted: 21 Feb 2020, 18:53
by sprstdlyscottsmn
eloise wrote:I think length and width can be deceiving because they could have different wing shape and vastly different area

That is the entire point of that section, to show how densely packed something is inside its Spot Area (a term used by the Navy for describing the actual amount of space a plane takes in the hangar deck).

eloise wrote:But SPEAR is very small, smaller than a short range air to air missile. And a short range air to air missile only has RCS about 0.03 m2 frontally

if you want to make a general argument that SPEAR should be lower than 0.1 I will listen, but length has little to do with RCS. SPEAR is 7in across, the same size as an AMRAAM and wider than a Sidewinder, and has a large rounded glass nose. The overall design of SPEAR shows no LO considerations. I see no reason for SPEAR to not have the highest RCS betwen itself, the SLAM-ER, and AAMs.

**EDIT** so a perfect circular reflector, which I am assuming the nose of SPEAR is, 7in across is 0.025m^2. I would think total RCS would be no less than twice this to account for edge refractions and surface creep, etc. With this in mind, I am inclined to reduce the RCS or SLAM-ER as it displays LO considerations in its design.

Re: Comparison by Spurts

Unread postPosted: 21 Feb 2020, 23:20
by mozza
sprstdlyscottsmn wrote:Here is the comparison currently. I am working on the F-16 model now.

Strike Fighters 2025_4.pdf


Rafale don't use Damocles pod anymore, he use the Talios pod.

https://www.thalesgroup.com/sites/defau ... S-GB_0.pdf

Re: Comparison by Spurts

Unread postPosted: 21 Feb 2020, 23:22
by wrightwing
eloise wrote:


But SPEAR is very small, smaller than a short range air to air missile. And a short range air to air missile only has RCS about 0.03 m2 frontally

RCS isn't based upon physical size. The shape is the more important factor.

Re: Comparison by Spurts

Unread postPosted: 22 Feb 2020, 00:46
by sprstdlyscottsmn
mozza wrote:
sprstdlyscottsmn wrote:Here is the comparison currently. I am working on the F-16 model now.

Strike Fighters 2025_4.pdf


Rafale don't use Damocles pod anymore, he use the Talios pod.

https://www.thalesgroup.com/sites/defau ... S-GB_0.pdf

Thanks!

Re: Comparison by Spurts

Unread postPosted: 22 Feb 2020, 01:01
by madrat
I don't think Talios is decommissioned. Damocles supplanted - not eliminates - the Talios, just as Talios did the same to the first generation pod.

Re: Comparison by Spurts

Unread postPosted: 22 Feb 2020, 04:40
by marsavian
Originating thread

viewtopic.php?f=55&t=25735

Re: Comparison by Spurts

Unread postPosted: 22 Feb 2020, 05:10
by eloise
sprstdlyscottsmn wrote:if you want to make a general argument that SPEAR should be lower than 0.1 I will listen, but length has little to do with RCS. SPEAR is 7in across, the same size as an AMRAAM and wider than a Sidewinder, and has a large rounded glass nose. The overall design of SPEAR shows no LO considerations. I see no reason for SPEAR to not have the highest RCS betwen itself, the SLAM-ER, and AAMs.
**EDIT** so a perfect circular reflector, which I am assuming the nose of SPEAR is, 7in across is 0.025m^2. I would think total RCS would be no less than twice this to account for edge refractions and surface creep, etc. With this in mind, I am inclined to reduce the RCS or SLAM-ER as it displays LO considerations in its design.

Except for faceted window, there are two problems with SLAM-ER
Saudi Arabia f-15s e   AGM-84H Standoff Land Attack Missiles-Expanded Response (SLAM-ER), 973 AGM-154C Joint Stand Off Weapons (JSOW), 400 AGM-84L Harpoon Block II missiles, 1000 GBU-39B Small Diameter Bomb.jpg

Firstly, the missile body is a pure cylinder, that is the perfect condition for creeping wave return. True VLO missiles such as Jassm, Jsow, Nsm never have pure cylinder body
Image
Secondly, it has four big tail fins, so they made up 4 right angle reflectors. On VLO missile such as Jsow the corner is acute and on Jassm, the horizontal fin is very small
Capture.PNG


Spear isn't fully cylindrical and the 3 small tail fins made obtuse angles
spear-1.006-640x360.jpg

Re: Comparison by Spurts

Unread postPosted: 22 Feb 2020, 15:05
by sprstdlyscottsmn
I see what you are saying. Per my previous post about the SPEAR window, I can't justify it going lower that 0.05, but you have a decent argument that SLAM-ER should be in the same class, not half the size.

Re: Comparison by Spurts

Unread postPosted: 23 Feb 2020, 03:36
by eloise
sprstdlyscottsmn wrote:I see what you are saying. Per my previous post about the SPEAR window, I can't justify it going lower that 0.05, but you have a decent argument that SLAM-ER should be in the same class, not half the size.

Another detail I want to suggest is
Stuart said the company is evaluating multiple sources for the aft actuator solution and also for the new rocket motor design that, Jane's understands, is expected to deliver an engagement speed that is double that of the current AARGM. "Our assessment is that there are propulsion options out there that are high TRL and can quickly transition into a production scenario to meet the USN's timelines," he said.

While the propulsion type has yet to be decided, a ramjet solution has not been discounted. "The current Orbital ATK design concept is not a ramjet, but it certainly doesn't remove that potential. However, it will be the USN and its requirements office that make the final decision on where they want to go with propulsion," he said.

'Increased Survivability' is built into the AARGM ER requirement, although Stuart declined to comment on the specifics of the Orbital ATK solution, noting only that "speed is in the equation. We're going double the range in about the same amount of time, and you have to increase speed to achieve that; so speed in and of itself is an improvement to survivability. There are other aspects of our design solution that improve survivability, but these are not releasable".

https://www.janes.com/article/71285/orb ... gn-concept
AARGM is mach 2 - 150 km missile, So if AARGM-ER can fly 300 km in the same amount of time, I think it will reach Mach 4 (or have much higher cruising speed than AARGM, but AARGM-ER doesn't have ramjet motor so Iam more inclined that it is much faster)

Re: Comparison by Spurts

Unread postPosted: 23 Feb 2020, 05:23
by sprstdlyscottsmn
eloise wrote:
sprstdlyscottsmn wrote:I see what you are saying. Per my previous post about the SPEAR window, I can't justify it going lower that 0.05, but you have a decent argument that SLAM-ER should be in the same class, not half the size.

Another detail I want to suggest is
Stuart said the company is evaluating multiple sources for the aft actuator solution and also for the new rocket motor design that, Jane's understands, is expected to deliver an engagement speed that is double that of the current AARGM. "Our assessment is that there are propulsion options out there that are high TRL and can quickly transition into a production scenario to meet the USN's timelines," he said.

While the propulsion type has yet to be decided, a ramjet solution has not been discounted. "The current Orbital ATK design concept is not a ramjet, but it certainly doesn't remove that potential. However, it will be the USN and its requirements office that make the final decision on where they want to go with propulsion," he said.

'Increased Survivability' is built into the AARGM ER requirement, although Stuart declined to comment on the specifics of the Orbital ATK solution, noting only that "speed is in the equation. We're going double the range in about the same amount of time, and you have to increase speed to achieve that; so speed in and of itself is an improvement to survivability. There are other aspects of our design solution that improve survivability, but these are not releasable".

https://www.janes.com/article/71285/orb ... gn-concept
AARGM is mach 2 - 150 km missile, So if AARGM-ER can fly 300 km in the same amount of time, I think it will reach Mach 4 (or have much higher cruising speed than AARGM, but AARGM-ER doesn't have ramjet motor so Iam more inclined that it is much faster)

That one I will disagree with on the principles of physics. It is pure speculation that it has the same time of flight. Even if we say the new missile has half the drag of the old missile, it would only have 41% more speed/range for the same thrust/time/fuel mass. To have twice the speed even with half the drag coefficient would be 2 times the thrust, which would need 2 times the fuel. AARGM ER is not a larger missile than AARGM and has the same guidance and warhead, so there is nor feasible way for it to carry twice the fuel.

Re: Comparison by Spurts

Unread postPosted: 23 Feb 2020, 07:08
by eloise
sprstdlyscottsmn wrote:That one I will disagree with on the principles of physics. It is pure speculation that it has the same time of flight. Even if we say the new missile has half the drag of the old missile, it would only have 41% more speed/range for the same thrust/time/fuel mass. To have twice the speed even with half the drag coefficient would be 2 times the thrust, which would need 2 times the fuel. AARGM ER is not a larger missile than AARGM and has the same guidance and warhead, so there is nor feasible way for it to carry twice the fuel.

But AARGM-ER is a larger missile with wider diameter than AARGM
AARGM rocket motor diameter is 254 mm
AARGM rocket motor diameter is 290 mm
If the length of the rocket motor section is equally long, AARGM-ER will carry 29% more rocket fuel, but they removed the mid body wing/actuator section, so I think it is feasible for it to carry twice the fuel load.

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Re: Comparison by Spurts

Unread postPosted: 23 Feb 2020, 15:42
by sprstdlyscottsmn
The new propulsion section would need to be over 50% longer than the old one. Looking at the space between the find on the old one, and the removed control section, that might just be it.

Thank you for taking the time to go over your evidence with me on this, as it ended up causing my rebuttal to line up with your argument. Provided, of course, that the missile has half the drag coefficient by ditching the big fore wings.

Re: Comparison by Spurts

Unread postPosted: 23 Feb 2020, 18:46
by eloise
sprstdlyscottsmn wrote:The new propulsion section would need to be over 50% longer than the old one. Looking at the space between the find on the old one, and the removed control section, that might just be it.

Thank you for taking the time to go over your evidence with me on this, as it ended up causing my rebuttal to line up with your argument. Provided, of course, that the missile has half the drag coefficient by ditching the big fore wings.

Thank you for the great explaination too.
By the way, when we talk about mach 2 speed for AARGM and mach 4 speed for AARGM-ER, is it top speed or average speed?

Re: Comparison by Spurts

Unread postPosted: 23 Feb 2020, 18:50
by juretrn
Sprts,

you're the best! :notworthy: :notworthy:

Re: Comparison by Spurts

Unread postPosted: 23 Feb 2020, 20:04
by sprstdlyscottsmn
If fired from a good cruising altitude with a loft profile then there will not be as much speed lost. I treat it as an average speed for that reason. I do not go into as much investigation for the AG missiles as I treat them as fairly static, as their targets are static.

Re: Comparison by Spurts

Unread postPosted: 24 Feb 2020, 10:32
by eloise
sprstdlyscottsmn wrote:If fired from a good cruising altitude with a loft profile then there will not be as much speed lost. I treat it as an average speed for that reason. I do not go into as much investigation for the AG missiles as I treat them as fairly static, as their targets are static.

I find that Kh-15 has very similar kinematic specs with AARGM-ER
Kh-15 max range is 300 km, AARGM-ER max range is also 300 km
1ja1o.jpg

t3ULL.jpg

1.PNG

Kh-15 can climb to 40 km and reach Mach 5 in the final dive at target, I don't know if AARGM-ER is capable of the same thing, so I look closer
Kh-15 propellant is 44% of its length, Kh-15 is 478 cm long and 45.5 cm in diameter so the propellant volume is 3.42×10^5 cubic centimeter
AARGM-ER propellant is 49.6% of its length, AARGM-ER is 410 cm long and 29 cm in diameter so the propellant volume is 1.34×10^5 cubic centimeter
So Kh-15 carries 2.55 times more rocket propellant than AARGM-ER. But, Kh-15 diameter is 45.5 cm while AARGM-ER diameter is 29 cm so the cross section area of Kh-15 is 2.46 times greater than AARGM-ER. Because form drag is proportional to cross section area, AARGM-ER can reach the same speed as Kh-15 even though it carries less propellant. Is that reasonable ?

Re: Comparison by Spurts

Unread postPosted: 24 Feb 2020, 14:25
by sprstdlyscottsmn
the "drag is proportional to cross sectional area" is a bit of a misnomer, but it can be useful for first order approximations.

Re: Comparison by Spurts

Unread postPosted: 25 Feb 2020, 03:30
by eloise
sprstdlyscottsmn wrote:Here is the comparison currently. I am working on the F-16 model now.

Strike Fighters 2025_4.pdf

I have another question about these specs of these air to air missiles
Why is the boost time of MiCA, R-77-1 and AIM-9X so long?
Mica can boost almost as long as the sustain time of Meteor?

Re: Comparison by Spurts

Unread postPosted: 25 Feb 2020, 15:54
by sprstdlyscottsmn
eloise wrote:I have another question about these specs of these air to air missiles
Why is the boost time of MiCA, R-77-1 and AIM-9X so long?
Mica can boost almost as long as the sustain time of Meteor?

Those missiles are using single impulse motors, "boost-only", and have no sustaining charge. I try to assume this is the default motor condition of AAMs unless it is specifically stated otherwise or the listed performance specs are unobtainable otherwise.

Also, the Sustain time of the meteor is the minimum time, and it CAN sustain for ten times as long by throttling back.

Re: Comparison by Spurts

Unread postPosted: 25 Feb 2020, 17:01
by eloise
sprstdlyscottsmn wrote:Those missiles are using single impulse motors, "boost-only", and have no sustaining charge. I try to assume this is the default motor condition of AAMs unless it is specifically stated otherwise or the listed performance specs are unobtainable otherwise.

Also, the Sustain time of the meteor is the minimum time, and it CAN sustain for ten times as long by throttling back.

I get that, but except for Meteor and AIM-120D I feel like the boost and sustain time of the others are too long
I mean AIM-120 can boost for 7 seconds but MICA can boost for 20 seconds?
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C6ABAF22-16AC-4B89-BED7-38E397876D10.jpeg

Re: Comparison by Spurts

Unread postPosted: 25 Feb 2020, 17:20
by sprstdlyscottsmn
eloise wrote:I get that, but except for Meteor and AIM-120D I feel like the boost and sustain time of the others are too long
I mean AIM-120 can boost for 7 seconds but MICA can boost for 20 seconds?

AIM-120 boost only for 8s, not 7, and at nearly 4,500lbt. It gets to Mach 4 in about 3nm. It uses loft in order to get its range.

MICA has a 20s motor, yes, but with only 1,485lbt it takes 7nm to reach Mach 4. Even with loft it does not come anywhere close to the range of the AIM-120D because of the high drag fins on a lightweight missile (see it's crazy high Dogfight score?). I did not like what I had to do with the MICA, but it was the only way I found to get the kind of range it is reported to have.

My missile model requires me to make a LOT of assumptions and I have to play with a lot of parameters to get the reported performance, since motor information is generally non-existant.

Re: Comparison by Spurts

Unread postPosted: 25 Feb 2020, 17:43
by sprstdlyscottsmn
for example, if I change the MICA motor to 8s at 3700lbt and increase loft to 25 degrees (same burn time and loft as AIM-120D) it actually loses range and it's speed goes to over Mach 5 (in 4nm).

If I leave loft alone and change it to 2s Boost at ~5600lbt and 10s Sustain at ~1800lbt the top speed goes up a little but it still solidly in the Mach 4 range, but it still loses flight range. In effect, with a 20deg loft the MICA needs to still be doing Mach 4 from 9NM on to reach 80km flight range in under 180s. No matter how I slice it, it needs 20s of motor burn time to get there. Even 2s boost and 17s sustain wont reach the range needed.

Don't get hung up on the terms "boost" and "sustain". Sustain only applies if there are two thrust levels. For a given ISP and Fuel Weight, there is only so much "delta V" available. The use of single pulse or duel pulse thrust levels only change HOW the delta V is applied.

Case in point, two 20s motors for MICA, with a "boost/sustain" thrust ratio of 3, a 2s/18s boost/sust time split results in the boost phase burning 12.5% o the fuel per second while the sustain phase burns 4.2% per second. a 20 "Boost" burns 5.0% of fuel per second. Both provide 29,700lbt-s (110lb motor with 270 ISP)

Re: Comparison by Spurts

Unread postPosted: 25 Feb 2020, 17:56
by eloise
I see your reasoning but I think the range value on internet may not be correct.
For MiCA I think you can calculate the motor burn time from this video

Re: Comparison by Spurts

Unread postPosted: 25 Feb 2020, 18:34
by sprstdlyscottsmn
That video suggests one of three things

SL version of MICA uses a different motor entirely (unlikely)
MICA has a ~3.5s Boost only motor (unlikely)
MICA has ~3.5s boost phase and a much lower thrust sustain phase (most likely)

" On October 23, 2008, 15:30, at CELM, Biscarosse (Landes), a VL MICA missile successfully performed the last of its 14 test firings meaning it is now ready for mass production. The target drone was flying at low level, over the sea, 12 km away; despite this distance, MICA, equipped with an active radar seeker, locked on the target and shot it down."

So we know a surface launch against a low altitude target is engageable from 12km (6.5nm).

Let's look at option 2 first.
a 3.5 motor burn time would do this, but the final speed would be a mere 0.36M.

Option 3
a 3.5s boost and 16.5s sustain (to stay with my 20s total burn time) with a 5:1 thrust ratio increases final speed to 0.83M

Option 2 for comparison test
missile hits Mach 5.75 but is down below Mach 1 by 24nm

Option 3 for comparison test
missile hits 3.77 Mach and loses 0.1nm of flight range. This is consistent with the MICA being a "Mach 4 missile with 80km range"
If I change the boost thrust ratio to 3 top speed becomes 3.99 Mach and range increases by 0.4nm, also consistent with "M4 80km"

After watching that video and running numbers I see reason to alter the MICA motor to Option 3 with a 3:1 thrust ratio.

Re: Comparison by Spurts

Unread postPosted: 26 Feb 2020, 04:15
by eloise
sprstdlyscottsmn wrote:That video suggests one of three things

SL version of MICA uses a different motor entirely (unlikely)
MICA has a ~3.5s Boost only motor (unlikely)
MICA has ~3.5s boost phase and a much lower thrust sustain phase (most likely)

" On October 23, 2008, 15:30, at CELM, Biscarosse (Landes), a VL MICA missile successfully performed the last of its 14 test firings meaning it is now ready for mass production. The target drone was flying at low level, over the sea, 12 km away; despite this distance, MICA, equipped with an active radar seeker, locked on the target and shot it down."

So we know a surface launch against a low altitude target is engageable from 12km (6.5nm).

Let's look at option 2 first.
a 3.5 motor burn time would do this, but the final speed would be a mere 0.36M.

Option 3
a 3.5s boost and 16.5s sustain (to stay with my 20s total burn time) with a 5:1 thrust ratio increases final speed to 0.83M

Option 2 for comparison test
missile hits Mach 5.75 but is down below Mach 1 by 24nm

Option 3 for comparison test
missile hits 3.77 Mach and loses 0.1nm of flight range. This is consistent with the MICA being a "Mach 4 missile with 80km range"
If I change the boost thrust ratio to 3 top speed becomes 3.99 Mach and range increases by 0.4nm, also consistent with "M4 80km"

After watching that video and running numbers I see reason to alter the MICA motor to Option 3 with a 3:1 thrust ratio.

I get your point but I feel uneasy because this video shows very quick burn motor
I screenshot some parts of it, we are lucky that there is a time indicator on the top of the video
The boost motor start at 13:52:31:319 and end at 13:52:34:339 so the boost phase operate for 3 seconds give or take
Mica flame out and the smoke trail stop at 13:52:36:739 so the sustain phase burn for 2.3 seconds or does motor flame stop glowing in the sustain phase?
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Re: Comparison by Spurts

Unread postPosted: 26 Feb 2020, 04:40
by eloise
I also find a video of AIM-132 ASRAAM


The motor burn bright start at 0:18 then shut down fully at 0:22 so I think it is a 4 seconds full boost motor instead of 2 seconds boost and 20 seconds sustain, is that possible?

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Re: Comparison by Spurts

Unread postPosted: 26 Feb 2020, 16:17
by sprstdlyscottsmn
In short, no. No missile is going to have anything even close to medium range with 4s or less of total thrust. The only plausible answer is that the sustain thrust does not produce enough "glow" for the video capture. The AIM-132 was supposed to be a "BVR" missile with more range than Sidewinder, that was the whole point.

Re: Comparison by Spurts

Unread postPosted: 26 Feb 2020, 18:32
by eloise
sprstdlyscottsmn wrote:In short, no. No missile is going to have anything even close to medium range with 4s or less of total thrust.

Can you please explain to me why can't they do that? :(
AIM-120C- motor burn for 7.77 seconds so shouldn't AIM-132 burning for 4 seconds have about 51% the range? The thrust is lower but AIM-132 is smaller too. And what if the burn time is low but the thrust is very high? similar to a gun

Re: Comparison by Spurts

Unread postPosted: 26 Feb 2020, 19:35
by sprstdlyscottsmn
AIM-120 achieves phenomenal range off a relatively short, but very powerful, burn combined with a long, thin body and small fins that provide very little drag and a high lofting trajectory. By the time the motor of the AIM-120 burned out the missile is already over 5,000ft higher than the launching aircraft and traveling 25 degrees up into thin air at Mach 4.22.

The AIM-132 has the same diameter as the AIM-120 but it shorter, it has a lower fineness ratio which increases drag. It has only small fins on the rear, so the form drag from fins is smaller, but that means most the lift is coming from the body, which comes with more drag.

If I take the AIM-32 to a single 4s pulse... and acknowledge that it must have datalink for LOAL capability and as such CAN utilize a loft profile (lofting was not an assumption I was allowing before), and reduce the rocket motor mass by 18lb (it was nearly 45% of the missile weight before) I get a 4.75M top speed and a few tenths of a nm more range in the same time. I see it is performing a sharp pull instead of a ballistic curve, so the loft I gave it may be non-optimal for the time of flight limit.

So, the AIM-132 might have a 4s motor, but no way can MICA make twice the range on the same burn, not with all that fin.

Re: Comparison by Spurts

Unread postPosted: 27 Feb 2020, 02:59
by eloise
sprstdlyscottsmn wrote:AIM-120 achieves phenomenal range off a relatively short, but very powerful, burn combined with a long, thin body and small fins that provide very little drag and a high lofting trajectory. By the time the motor of the AIM-120 burned out the missile is already over 5,000ft higher than the launching aircraft and traveling 25 degrees up into thin air at Mach 4.22.

The AIM-132 has the same diameter as the AIM-120 but it shorter, it has a lower fineness ratio which increases drag. It has only small fins on the rear, so the form drag from fins is smaller, but that means most the lift is coming from the body, which comes with more drag.

If I take the AIM-32 to a single 4s pulse... and acknowledge that it must have datalink for LOAL capability and as such CAN utilize a loft profile (lofting was not an assumption I was allowing before), and reduce the rocket motor mass by 18lb (it was nearly 45% of the missile weight before) I get a 4.75M top speed and a few tenths of a nm more range in the same time. I see it is performing a sharp pull instead of a ballistic curve, so the loft I gave it may be non-optimal for the time of flight limit.

So, the AIM-132 might have a 4s motor, but no way can MICA make twice the range on the same burn, not with all that fin.

Thank you,now I understand
Any how, I have just double check and the diameter of AIM-132 is 165 mm compared to 180 mm of AIM-120, it has LOAL ability but unfortunately no datalink.
Do you think Peregrine can match Mica range? Peregrine is about 1.8m (6ft) long and 68kg (150lb)
Capture.PNG

mica.jpg

Re: Comparison by Spurts

Unread postPosted: 27 Feb 2020, 04:57
by sprstdlyscottsmn
eloise wrote:
Any how, I have just double check and the diameter of AIM-132 is 165 mm compared to 180 mm of AIM-120, it has LOAL ability but unfortunately no datalink.
Do you think Peregrine can match Mica range? Peregrine is about 1.8m (6ft) long and 68kg (150lb)

AIM-132 MOTOR is 165mm, the AIM-120 BODY is 180mm. They both are a 7in, 180mm body. AIM-132 has to have a one-way datalink in order to do LOAL doesn't it?

Peregrine (and CUDA before that) hare "HalfRAAM" missile with two thirds of the motor of an AMRAAM. They are typically HTK missiles and as such replace the warhead space with more fuel. Those can have tremendous range potential, somewhere between MICA and AMRAAM I expect. Tomorrow I will check my missile sim to see if I had modeled a Peregrine before. A missile that small would do best with a low and slow burn.

Re: Comparison by Spurts

Unread postPosted: 27 Feb 2020, 05:31
by mozza
Just a little add:MICA is part of the SPECTRA suite since the IR ones on the wingtips act as an IRST during the flight and their sensors are "fused" in SPECTRA, (MICA is also HOBS btw)
So maybe the EO/IR part need to be updated.
And about your debate, i don't know why you think that long fin on a missile = big drag and = less range? If it's true why Raytheon and MBDA do that ? Maybe it's more complex than that...?

Re: Comparison by Spurts

Unread postPosted: 27 Feb 2020, 06:53
by eloise
sprstdlyscottsmn wrote:AIM-132 MOTOR is 165mm, the AIM-120 BODY is 180mm. They both are a 7in, 180mm body. AIM-132 has to have a one-way datalink in order to do LOAL doesn't it?.

I think the diameter for missile body in both case, AIM-132 is visibly smaller than Meteor and Meteor and AIM-120 have the same diameter. Missiles doesn't need datalink for LOAL if they have automatic target acquisition capabilities
D3569F28-F76B-419D-900E-B5DA5839BC5F.jpeg

BA657A03-1863-45A1-9296-3F856D716ED9.jpeg

Re: Comparison by Spurts

Unread postPosted: 27 Feb 2020, 08:00
by eloise
mozza wrote:Just a little add:MICA is part of the SPECTRA suite since the IR ones on the wingtips act as an IRST during the flight and their sensors are "fused" in SPECTRA, (MICA is also HOBS btw)
So maybe the EO/IR part need to be updated.
And about your debate, i don't know why you think that long fin on a missile = big drag and = less range? If it's true why Raytheon and MBDA do that ? Maybe it's more complex than that...?

MICA was added to Spectra because the IIR component of FSO is currently removed so the MICA sensor will provide some interim capabilities until a new IIR sensor is added to FSO, but it cant match capabilities of true IRST due to cooling and aperture limitation
Big wing add more lift, so your missile is more maneuverable at high altitude or low speed, but big wings also add more drag

Re: Comparison by Spurts

Unread postPosted: 27 Feb 2020, 13:33
by sferrin
sprstdlyscottsmn wrote:Peregrine (and CUDA before that) hare "HalfRAAM" missile with two thirds of the motor of an AMRAAM.

Peregrine is Raytheon. CUDA is LM. (CUDA is not dead BTW.)


sprstdlyscottsmn wrote:They are typically HTK missiles and as such replace the warhead space with more fuel.

Peregrine has a blast/frag warhead.

Re: Comparison by Spurts

Unread postPosted: 27 Feb 2020, 15:05
by sprstdlyscottsmn
sferrin wrote:Peregrine has a blast/frag warhead.

I was unaware of that, I assumed it was just like the CUDA.

Re: Comparison by Spurts

Unread postPosted: 27 Feb 2020, 16:25
by eloise
sferrin wrote:Peregrine is Raytheon. CUDA is LM. (CUDA is not dead BTW.)

I heard it become a candidate for M-Rad
1.PNG

2.PNG

Re: Comparison by Spurts

Unread postPosted: 17 Mar 2020, 20:27
by sprstdlyscottsmn
Working on the thrust model for the F-16. Having low speed to max speed accelerations for ten thousand foot increments is so helpful. Matching speed, fuel, and distance for the given acceleration time within +- 2% plus getting to see where it's like "Okay, .67 to 1.83 happens pretty smoothly, 1.83 to 2.02 takes almost as long, doubles the fuel, and more than doubles the distance"

The HAF manual provides so much information. The biggest thing missing is the stores carriage/employment limits that I have only noticed on the F-15-1 so far.

Re: Comparison by Spurts

Unread postPosted: 17 Mar 2020, 23:57
by energo
sprstdlyscottsmn wrote:"Okay, .67 to 1.83 happens pretty smoothly, 1.83 to 2.02 takes almost as long, doubles the fuel, and more than doubles the distance"


Probably old news and not very relevant, but one RNoAF F-16A pilot once told me that pushing Mach 1.6 was like "hitting a wall". It wen't slowly from there. Mostly due to the inlet, I was led to believe. Most RNoAF pilots I've talked to have barely had it much past Mach 1.9 in FCSs. As one said, to the effect of: "I couldn't bother trying Mach 2. Not enough fuel!" This was way before the -220E, so it might not be accurate today.

Re: Comparison by Spurts

Unread postPosted: 18 Mar 2020, 00:03
by sprstdlyscottsmn
energo wrote:
sprstdlyscottsmn wrote:"Okay, .67 to 1.83 happens pretty smoothly, 1.83 to 2.02 takes almost as long, doubles the fuel, and more than doubles the distance"


Probably old news and not very relevant, but one RNoAF F-16A pilot once told me that pushing Mach 1.6 was like "hitting a wall". It wen't slowly from there. Mostly due to the inlet, I was led to believe. Most RNoAF pilots I've talked to have barely had it much past Mach 1.9 in FCSs. As one said, to the effect of: "I couldn't bother trying Mach 2. Not enough fuel!" This was way before the -220E, so it might not be accurate today.

I'm analyzing the -129

Re: Comparison by Spurts

Unread postPosted: 18 Mar 2020, 00:21
by energo
sprstdlyscottsmn wrote:I'm analyzing the -129


Absolutely, keep up the good work! :mrgreen:

Re: Comparison by Spurts

Unread postPosted: 18 Mar 2020, 02:00
by rheonomic
sprstdlyscottsmn wrote:Working on the thrust model for the F-16.

It's probably a shitty model but NASA TP-1538 (PDF) has a static engine model as a function of PLA, Mach, and altitude for an "F-16 like" aircraft. There's also an aero model that might be ok to ~M0.6 or so. There's a MATLAB version of the reduced model the Stevens & Lewis textbook has available here for non-commercial use.

Re: Comparison by Spurts

Unread postPosted: 07 Apr 2020, 12:07
by eloise
New AIM-120C model in DCS, closer to real life?

Re: Comparison by Spurts

Unread postPosted: 07 Apr 2020, 15:32
by sprstdlyscottsmn
There are a few takeaways from that video.

Aspect: These were head on shots.

Launch conditions: 1.6M from 50,000+ft... hmm, isn't there some Wunderjet that cruises at those kinds of conditions where it was stated it would roughly double launch ranges? Now it is highlighted why. The missiles were able to stay faster for longer in rarified atmosphere.

Target dynamics: The targets were all at high altitude so the missile never had to slow down in thicker air. The targets did not have much time to maneuver either so they did not have the opportunity to generate lateral separation.

Crunching numbers on the three shots

50nm shot, 64s time of flight, actual flight range 40.4nm (target covered the rest)
55nm shot, 74s time of flight, actual flight range 43.9nm
60nm shot, 75s time of flight, actual flight range 45.6nm

Re: Comparison by Spurts

Unread postPosted: 08 Apr 2020, 16:20
by sprstdlyscottsmn
Update: No update right now. During the midst of all this craziness I am also changing jobs and moving cross country.

Re: Comparison by Spurts

Unread postPosted: 08 Apr 2020, 17:23
by lamoey
sprstdlyscottsmn wrote:Update: No update right now. During the midst of all this craziness I am also changing jobs and moving cross country.


I'm please to hear that you have a job, under the current climate.

Re: Comparison by Spurts

Unread postPosted: 09 Apr 2020, 02:42
by eloise
sprstdlyscottsmn wrote:Update: No update right now. During the midst of all this craziness I am also changing jobs and moving cross country.

It is scary, I hope US find out the cure soon

sprstdlyscottsmn wrote:There are a few takeaways from that video.

Aspect: These were head on shots.

Launch conditions: 1.6M from 50,000+ft... hmm, isn't there some Wunderjet that cruises at those kinds of conditions where it was stated it would roughly double launch ranges? Now it is highlighted why. The missiles were able to stay faster for longer in rarified atmosphere.

Target dynamics: The targets were all at high altitude so the missile never had to slow down in thicker air. The targets did not have much time to maneuver either so they did not have the opportunity to generate lateral separation.

Crunching numbers on the three shots

50nm shot, 64s time of flight, actual flight range 40.4nm (target covered the rest)
55nm shot, 74s time of flight, actual flight range 43.9nm
60nm shot, 75s time of flight, actual flight range 45.6nm

Thank you

Re: Comparison by Spurts

Unread postPosted: 18 May 2020, 16:59
by sprstdlyscottsmn
Okay, so now I do have an update! I have "finalized" my F-16V model. Now on to mission work.

Re: Comparison by Spurts

Unread postPosted: 19 May 2020, 02:35
by sprstdlyscottsmn
I swear, 100 hours to make the model, and in 5 hours after that I have have the analysis work done.

Re: Comparison by Spurts

Unread postPosted: 19 May 2020, 02:44
by eloise
sprstdlyscottsmn wrote:I swear, 100 hours to make the model, and in 5 hours after that I have have the analysis work done.

I knew your model take very long to make but holy **** 100 hours, I'm deeply impressed.

Re: Comparison by Spurts

Unread postPosted: 04 Jul 2020, 03:23
by sprstdlyscottsmn
So, I made a statement about 5 hours getting what I estimated to be half of the analysis work done. I took the time to count the rest. 280 minutes to finish, or just over 4.5 hours. The Viper is finished. On to the Super Hornet and the last thing I have a manual for.

Strike Fighters 2025_5.pdf
(1.07 MiB) Downloaded 290 times

Re: Comparison by Spurts

Unread postPosted: 04 Jul 2020, 05:19
by 35_aoa
energo wrote:
Probably old news and not very relevant, but one RNoAF F-16A pilot once told me that pushing Mach 1.6 was like "hitting a wall". It wen't slowly from there. Mostly due to the inlet, I was led to believe. Most RNoAF pilots I've talked to have barely had it much past Mach 1.9 in FCSs. As one said, to the effect of: "I couldn't bother trying Mach 2. Not enough fuel!" This was way before the -220E, so it might not be accurate today.


With a centerline tank/pylons (or in a -B) yeah, I remember 1.6 being about where the ride got rough and things slowed down. It's been a while, but I remember a completely slick -A moving pretty steadily up to about 1.8 and then hitting the proverbial brick wall. I know one guy who got it to 1.99......nobody who bested 2.0, though I know it has happened plenty of times.....I believe an A was lost in the early years exceeding the mach limit (memory is fading now and don't have a -1 to reference, but I seem to remember 2.01 or 2.02M being the lim) in a dive, when the engine turbine section (or something of that nature) disintegrated violently and ripped the airplane apart.....maybe gums remembers that tale that was told to me many many years later when learning to fly the same old bird.

Re: Comparison by Spurts

Unread postPosted: 04 Jul 2020, 13:41
by sprstdlyscottsmn

Re: Comparison by Spurts

Unread postPosted: 05 Jul 2020, 04:49
by element1loop
sprstdlyscottsmn wrote:
Launch conditions: 1.6M from 50,000+ft... hmm, isn't there some Wunderjet that cruises at those kinds of conditions where it was stated it would roughly double launch ranges?


For a flight of 4 verses 4 x F-35A in a stealth attack situation:

LPI to detect, LPI track, upgraded EOTS does the LOCK, launch, no RWR alert, hold EOTS fused lock as you immediately beam the target at about the same altitude and speed as the launch (thus harder to get a return shot to hit you and still good RCS) so to maintain a better radial distance to target. Then a second shot on same, or a trailing wingman with a beamed HOBS shot as they get closer (with a high AOA launch and weapons bays facing away from their radars), if the first misses. Then maintain beam again to keep or extend the radial distance (with a 135 degrees turn away, heading as EOTS or else DAS maintains the lock) and IR blocker in the nozzle keeps the F-35A hidden.

Take another HOBS shot if any survive which didn't turn away, or rather, didn't know where to turn at all, and went the wrong way. So flank them and send one of your F-35As lower as it beams after its initial launch. You've not even used up your fuel doing anything exceptional here, and still have potentially 6 to 7 more BVR missiles left on each F-35A. So anything less than a genuine stealth fighter as the target hasn't got much hope of surviving that sort of attack.

The question in my mind is will a target's MAWS or a modern IRST, or DAS-ski see the missile boost, and track a coasting thermal signature from that more obvious boost transient? Will a newer Western AAM design focus on stealth shots? Yeah, I think so.

Even so the IR and UV MAWS don't provide range information to pilots, so the target sensors can only estimate range from observing luminosity changes during the boost. In which case they'll need to almost immediately go defensive, as a launch is detected (it could be a shorter range IR, all you know is you're inside its acceptable launch parameters), due to uncertainty of the launch range of a stealth jet launch, plus they will get slower and lose some altitude as they react to a launch detection pointed at them. And they're going to be wondering aloud where those shooters really are, so maybe delay the F-35 flight's first volley until the targets are already partially flanked.

However, new low-IR and low-UV emission motors can take even the MAWS warning option away from them, especially with an on-boresight geometry, for the initial opening shots at longer ranges.

If they don't see those launched they're done. But if they do see it (I'm supposing they will) they must react early and lose energy and altitude so their launch options just became less viable even if they did get a long-range track and lock, let's face it, that's unlikely too. So they're already defensive and you can keep them that way with lower energy as the radius halves, then missiles falling into thicker air becomes less of an impediment as radius reduces anyway.

But you've already sent at least one of your F-35As to dive under them or maintain level, and maintain one above them, with another each side, beaming off HOBS shots if the targets try to get out of the fight area. So the chances are few will escape such a BVR stealth attack, whether their MAWS alerted them or not.

But against a stealthy flight opponent, the side with the HF, or long VHF defensive early-warning cues will dominate the BVR setups within a stealth v stealth BVR ambush fight. Except the superior DAS sensor and fusion plus EOTS is going to provide the greater SA advantage to prosecute that sort of fight with. That's an interesting set of challenges.

And if both formations are wide-open, that changes the potential to ambush them as well.

Thanks for your new update.

Re: Comparison by Spurts

Unread postPosted: 05 Jul 2020, 11:25
by garrya
sprstdlyscottsmn wrote:So, I made a statement about 5 hours getting what I estimated to be half of the analysis work done. I took the time to count the rest. 280 minutes to finish, or just over 4.5 hours. The Viper is finished. On to the Super Hornet and the last thing I have a manual for.

The attachment Strike Fighters 2025_5.pdf is no longer available

I thought there is no EM chart for the super hornet?
P/s: I love this table format
Capture.PNG

Capture.PNG

Quick, easy to understand

Re: Comparison by Spurts

Unread postPosted: 05 Jul 2020, 13:43
by sprstdlyscottsmn
There no EM, but still a manual.

Re: Comparison by Spurts

Unread postPosted: 26 Jul 2020, 15:33
by sprstdlyscottsmn
I was going to make a joke along the lines of "For the last 5 people interested..." but I see that the last upload I made had 122 downloads, so... wow. Thanks!

Anyway, 8.5 hours into the SHornet model and it is going GREAT compared to the others. While I don't have much for the turning, I have VERY detailed AB thrust data for two altitudes which means my drag model is more accurate which means filling in remaining thrust values from acceleration charts (of which there are many) is more accurate. Also, there are so many Specific Range charts what someone COULD (I certainly will not) build up to 100 flight envelopes for mil power under 0.9M. Each altitude listed (5,000ft increments) has charts for ten weights and each weight has up to ten DI values listed. This is allowing me to build a very accurate (within my modeling resolution) fuel burn table. Once this is done then I will calibrate the weapons drag and I will be "off to the races" on the analysis portions.

*Edit - Looking at payload combinations.... I hope the Block III has a higher Gross Weight than the Block II.

Re: Comparison by Spurts

Unread postPosted: 27 Jul 2020, 06:07
by eloise
sprstdlyscottsmn wrote:So, I made a statement about 5 hours getting what I estimated to be half of the analysis work done. I took the time to count the rest. 280 minutes to finish, or just over 4.5 hours. The Viper is finished. On to the Super Hornet and the last thing I have a manual for.

The attachment Strike Fighters 2025_5.pdf is no longer available

I have some suggestion, hope you don't mind
I think the way to arrive to these number in red box is a ambiguous and I think it is hard to reader to understand why the formular is made like that
55555555555555.PNG

Capture.PNG


I think you meant to write range for the horizontal line and altitude for the vertical line?
2222.PNG


This load out is weird:
If we goes for 2 EFT + 2 HARM + 2 AIM-9 + 2 AIM-120 + IRST21 + ATP then we only have the centerline station left, but I don't think SDB can be carried on the centerline
3333.PNG

f-16v.jpeg

Re: Comparison by Spurts

Unread postPosted: 27 Jul 2020, 10:42
by eloise
Does this proves that F-16E/F and F-15SA can still be a threat to Mig-31 in BVR combat?
1.PNG

Re: Comparison by Spurts

Unread postPosted: 27 Jul 2020, 11:30
by sprstdlyscottsmn
eloise wrote:I have some suggestion, hope you don't mind
I think the way to arrive to these number in red box is a ambiguous and I think it is hard to reader to understand why the formular is made like that

Always happy to take suggestions to improve readability. My calculations for missile ratings is ambiguous because I just made it up. General is for traits that are not inherently for dogfighting or BVR but still matter. Dogfight is for factors that make no difference in a BVR shot and BVR is for factors that make no difference in a Dogfight. I weighted them (using the divisors of 5, 100, and 20) to make it that a rating of 100 in any of them was really good and beyond 100 was exceptional.

eloise wrote:
I think you meant to write range for the horizontal line and altitude for the vertical line?

Those are just titles, but yes they do refer to the vertical axis. I left it as assumed the reader would know that the horizontal axis was range in NM in all cases, which is not fair to the readers. I will have to make a note.

eloise wrote:
This load out is weird:
If we goes for 2 EFT + 2 HARM + 2 AIM-9 + 2 AIM-120 + IRST21 + ATP then we only have the centerline station left, but I don't think SDB can be carried on the centerline
3333.PNG

f-16v.jpeg

Ugh, I know. I often can't find data I need and have to make, or force, assumptions. In this case I was stuck with "force centerline SDB station so we can have two wing tanks" or "center EFT only and twin rack 500lb on each inboard pylon" as this loadout was specifically about to SEAD munitions and four other precision munitions. I guess I COULD go with the ugly configuration of wing mounted SDB on one side and tank on the other with a tank on the center. I was shying away from asymmetry but I am being forced into it with the SHornet anyway.

eloise wrote:Does this proves that F-16E/F and F-15SA can still be a threat to Mig-31 in BVR combat?

That is exactly what I added that in for, to show the relative threat to a MiG-31.

Thanks for the feedback!

Re: Comparison by Spurts

Unread postPosted: 28 Jul 2020, 10:04
by eloise
sprstdlyscottsmn wrote:That is exactly what I added that in for, to show the relative threat to a MiG-31.
Thanks for the feedback!

I see the F-15SA limited to Mach 1.4, so that means it carries CFT? How about F-16? Is it also fitted with CFT in this scenario?Doesn't it limit their A2A potential when they are forced to carry CFTs? lower acceleration, higher RCS, lower top speed?
and can you also simulate range of R-37M (RVV-BD) from Su-35 against the same type of target? Su-35 recently get to carry them.
EUrpbsFVAAA3Sts.jpg

Re: Comparison by Spurts

Unread postPosted: 28 Jul 2020, 11:11
by sprstdlyscottsmn
I see the F-15SA limited to Mach 1.4, so that means it carries CFT? How about F-16? Is it also fitted with CFT in this scenario?Doesn't it limit their A2A potential when they are forced to carry CFTs? lower acceleration, higher RCS, lower top speed?
and can you also simulate range of R-37M (RVV-BD) from Su-35 against the same type of target?

They are carrying CFTs but the 1.4 Mach wasn't a limit issue, it was the Mach that allowed the highest altitude. I'm intentionally not doing the Su-35 right now. Other priorities.

Re: Comparison by Spurts

Unread postPosted: 28 Jul 2020, 14:41
by basher54321
The estimated flight profiles you have done for Meteor are certainly interesting. 8)

Re: Comparison by Spurts

Unread postPosted: 28 Jul 2020, 14:50
by sprstdlyscottsmn
basher54321 wrote:The estimated flight profiles you have done for Meteor are certainly interesting. 8)
Yeah, that was the minimum throttle profile. I spent a lot of time trying to find flight profile and flight time data. I look forward to running data for Meteor equipped planes.

Re: Comparison by Spurts

Unread postPosted: 13 Aug 2020, 16:39
by sprstdlyscottsmn
The Block III Rhino needs a higher MGTOW... and the EPE motors for supersonic operation, but man is it a beast subsonic.

Re: Comparison by Spurts

Unread postPosted: 14 Aug 2020, 03:21
by eloise
sprstdlyscottsmn wrote:The Block III Rhino needs a higher MGTOW... and the EPE motors for supersonic operation, but man is it a beast subsonic.

Is it a beast with or without EPE motors?
how is it compared to F-16, F-15, F-35?

Re: Comparison by Spurts

Unread postPosted: 14 Aug 2020, 17:43
by sprstdlyscottsmn
Subsonic beast without EPE motors. With a heavy load the SHornet has subsonic acceleration nearly on par with the F-15EX, far greater than the F16V

Re: Comparison by Spurts

Unread postPosted: 14 Aug 2020, 18:09
by eloise
sprstdlyscottsmn wrote:Subsonic beast without EPE motors. With a heavy load the SHornet has subsonic acceleration nearly on par with the F-15EX, far greater than the F16V

What is the kind of heavy load you are talking about? Is it 3 fuel tank , 2 bombs and 4 AMRAAM?
How about air to air loadout such as 6 AIM-120?
How is it compared to F-16E/F (F-110-GE-132 engine)?

Re: Comparison by Spurts

Unread postPosted: 14 Aug 2020, 23:21
by sprstdlyscottsmn
The Max Weight and Max Drag loads. I think for the Rhino it was CFT, Centerline tank, 4 AAM, a twin mount laser Zuni, two SDB racks, two twin mount 1000# JDAMS, and a targeting pod.

I don't have an F-16E model but if I did it would be a heavier and dragier but more powerful V model.

Re: Comparison by Spurts

Unread postPosted: 15 Aug 2020, 03:30
by sprstdlyscottsmn
With the Air to Air loads it is the same story, keeps pace with the EX and edges out the V. It's once wave drag comes into play that the SHornet falls apart.

Re: Comparison by Spurts

Unread postPosted: 15 Aug 2020, 17:12
by wrightwing
It'd definitely be interesting to see what an EPE equipped version could do, seeing the current performance.

Re: Comparison by Spurts

Unread postPosted: 15 Aug 2020, 22:14
by sprstdlyscottsmn
I'm curious about that too. I can try a rudimentary thrust increase at some point, but I want to finish first.

Re: Comparison by Spurts

Unread postPosted: 16 Aug 2020, 22:45
by marauder2048
sprstdlyscottsmn wrote:The Max Weight and Max Drag loads. I think for the Rhino it was CFT, Centerline tank, 4 AAM, a twin mount laser Zuni, two SDB racks


So racks it doesn't carry for weapons it doesn't have?

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 02:07
by wrightwing
marauder2048 wrote:
sprstdlyscottsmn wrote:The Max Weight and Max Drag loads. I think for the Rhino it was CFT, Centerline tank, 4 AAM, a twin mount laser Zuni, two SDB racks


So racks it doesn't carry for weapons it doesn't have?

Which racks/weapons would those be?

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 02:09
by sprstdlyscottsmn
marauder2048 wrote:
sprstdlyscottsmn wrote:The Max Weight and Max Drag loads. I think for the Rhino it was CFT, Centerline tank, 4 AAM, a twin mount laser Zuni, two SDB racks


So racks it doesn't carry for weapons it doesn't have?

Can you explain? My understanding is the SDB is used on nearly everything and that Laser Zuni is available on all Hornets

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 02:48
by marauder2048
sprstdlyscottsmn wrote:
marauder2048 wrote:
sprstdlyscottsmn wrote:The Max Weight and Max Drag loads. I think for the Rhino it was CFT, Centerline tank, 4 AAM, a twin mount laser Zuni, two SDB racks


So racks it doesn't carry for weapons it doesn't have?

Can you explain? My understanding is the SDB is used on nearly everything and that Laser Zuni is available on all Hornets


The Navy never bought SDB I for the Super Hornet and AFAIK, APKWS was never qualified.
And I'm guessing the pylon cant practically precludes FFARs on the Super Hornet.

SDB II is being qualified.

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 08:17
by 35_aoa
marauder2048 wrote:
The Navy never bought SDB I for the Super Hornet and AFAIK, APKWS was never qualified.
And I'm guessing the pylon cant practically precludes FFARs on the Super Hornet.

SDB II is being qualified.


I think his confusion is based on 1) (as you mentioned) USN is buying SDBII for Super Hornet but never SDB1, and 2) USMC got APKWS for their Hornet fleet (though USN did not). SH cannot carry/fire unguided rockets like the Hornet can, owing to the pylon cant.

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 09:27
by eloise
sprstdlyscottsmn wrote:I'm curious about that too. I can try a rudimentary thrust increase at some point, but I want to finish first.

Hold up, as far as I know, F-18 Super Hornet block III currently use the same engine as normal F-18E/F Super Hornet, it only add the CFT?
and even with that, It has better subsonic acceleration than F-16 and F-35? How come?

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 11:02
by sprstdlyscottsmn
35_aoa wrote:
marauder2048 wrote:
The Navy never bought SDB I for the Super Hornet and AFAIK, APKWS was never qualified.
And I'm guessing the pylon cant practically precludes FFARs on the Super Hornet.

SDB II is being qualified.


I think his confusion is based on 1) (as you mentioned) USN is buying SDBII for Super Hornet but never SDB1, and 2) USMC got APKWS for their Hornet fleet (though USN did not). SH cannot carry/fire unguided rockets like the Hornet can, owing to the pylon cant.


Thank you marauder for clarifying and 35_aoa for confirming. I can easily see the sources of confusion.

I said SDB because for the purposes of my drag model I and II are the same. My textual description of the loadout was IIs. Sorry for not being clear.

APKWS is a different system than Laser Zuni, but you comments made me dig deeper. I only see LZuni being purchased for the USMC, not USN. So there's problem 1. I did not consider the pylon cant to be something the weapon computer would be unable to account for, and since the NATOPS for loadouts specifically lists LAU-10 it definitely led me to the "if it can carry a LAU-10 it can carry a LZuni", but I am not about to argue with 35_aoa on this. If he says it can't be done than the NATOPS is wrong. So there's problem 2.

I will remove the LZuni from the comparison and go with more SDB II racks I suppose. Thank you marauder2048 and 35_aoa for pointing this out to me!

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 11:13
by sprstdlyscottsmn
eloise wrote:
sprstdlyscottsmn wrote:I'm curious about that too. I can try a rudimentary thrust increase at some point, but I want to finish first.

Hold up, as far as I know, F-18 Super Hornet block III currently use the same engine as normal F-18E/F Super Hornet, it only add the CFT?
and even with that, It has better subsonic acceleration than F-16 and F-35? How come?


I haven't done the F-35 yet, so I can't say. Remember the statement there is "clean block 50", not "loaded block 70 with CFTs" so the F-35A is likely going to shatter these values as for "Clean, Air, SEAD" loadouts the only real difference will be a little extra weight, not friction drag.

The acceleration charts in the NATOPS start from Max Endurance speeds so I was able to plot, as an example, from 0.619M to 1.466M at 30,000ft with a starting weight of 42,000lb with 2 AIM-9s and 2 AIM-120s with speed checks at 0.9, 1.1, 1.2, 1.3, 1.35, 1.4, 1.425, 1.45, and 1.466M. the 1.0 minute line sites a little higher than the 1.1M line and the 0.9M line is less than halfway between the datum and the 1.0min line, meaning 22-25 seconds from 0.619M to 0.9M and ~30 seconds from there to 1.1M.

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 14:50
by eloise
sprstdlyscottsmn wrote:I haven't done the F-35 yet, so I can't say. Remember the statement there is "clean block 50", not "loaded block 70 with CFTs" so the F-35A is likely going to shatter these values as for "Clean, Air, SEAD" loadouts the only real difference will be a little extra weight, not friction drag

Block 70 is practically Block 50 with an AESA though
From the data we have the subsonic acceleration of F-35 is slightly better than F-16Block 50 with 2 external fuel tank and if I recall correctly, CFT generate much less drag than EFTs
F-16vsF-35-2.jpg

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 15:05
by sprstdlyscottsmn
It's not the drag, it's the weight. If you increase weight by 10% then acceleration is going to go down by ten percent.

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 16:36
by wrightwing
eloise wrote:
sprstdlyscottsmn wrote:I haven't done the F-35 yet, so I can't say. Remember the statement there is "clean block 50", not "loaded block 70 with CFTs" so the F-35A is likely going to shatter these values as for "Clean, Air, SEAD" loadouts the only real difference will be a little extra weight, not friction drag

Block 70 is practically Block 50 with an AESA though
From the data we have the subsonic acceleration of F-35 is slightly better than F-16Block 50 with 2 external fuel tank and if I recall correctly, CFT generate much less drag than EFTs
F-16vsF-35-2.jpg

According to that chart, the F-35A has a .2 second difference in acceleration with a clean Block 50. It's the B/C models that are comparable with the Block 50 with EFTs.

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 19:16
by johnwill
sprstdlyscottsmn wrote:It's not the drag, it's the weight. If you increase weight by 10% then acceleration is going to go down by ten percent.

You may be right, but it seems to me acceleration is determined by thrust, drag, and mass.

a = (t-d)/m

True enough acceleration is proportional to mass so long as thrust and drag are constant. But if mass is increased, drag goes up too. A 10% increase in mass will result in more than 10% reduced acceleration.

Re: Comparison by Spurts

Unread postPosted: 17 Aug 2020, 20:10
by sprstdlyscottsmn
johnwill wrote:
sprstdlyscottsmn wrote:It's not the drag, it's the weight. If you increase weight by 10% then acceleration is going to go down by ten percent.

You may be right, but it seems to me acceleration is determined by thrust, drag, and mass.

a = (t-d)/m

True enough acceleration is proportional to mass so long as thrust and drag are constant. But if mass is increased, drag goes up too. A 10% increase in mass will result in more than 10% reduced acceleration.

Of course, I was just giving a high level description about how a "dragless" (single digit DI) CFT can still drastically reduce the acceleration.

You bringing that the increased induced drag is very relevant to the fact that the SHornet and Viper manuals begin their acceleration stats from lower speeds (Max End in the SHornet case) where a ~10% increase in weight can be a ~5% increase in total drag. At higher altitude that can be a 10-20% reduction in excess thrust (T-D) which combined with the 10% higher mass gives a ~20-30% reduction in acceleration at the lower speeds. As speeds go up induced drag becomes less of a factor until we reach the point where wave drag becomes a dominant factor, then the CFTs still pay a heavy price.

Thanks for the reply johnwill

Re: Comparison by Spurts

Unread postPosted: 18 Aug 2020, 06:42
by 35_aoa
sprstdlyscottsmn wrote:I did not consider the pylon cant to be something the weapon computer would be unable to account for, and since the NATOPS for loadouts specifically lists LAU-10 it definitely led me to the "if it can carry a LAU-10 it can carry a LZuni", but I am not about to argue with 35_aoa on this. If he says it can't be done than the NATOPS is wrong. So there's problem 2.


Couple things here. I'd imagine the mission computers *could* provide a firing solution if the money was right and someone wanted to spend it, but unguided rocket usage is a pretty big corner case in combat. I shot plenty as a Hornet pilot in training but never carried any in combat. There was a very brief moment in somewhat recent history where they became en vogue again, but their reliability was proven very quickly to be unsuitable. I'd imagine the E/F program didn't find it cost effective to conduct the testing/modification required. If you think about what they are, unguided rockets, you can of course imagine the bizarre rudder antics you would have to commit to get them pointed at something off the nose. Possible of course, even programmable in terms of aiming reticle, but probably not worth the time given how irrelevant unguided munitions are in today's battlefield as it currently stands (20/30mm gun or crew served weapons notwithstanding).

On the point of the LAU-10, my *google* search yields that is pod for the 5" ZUNI. We only carried the 2.75" Hydra in the Hornet, never heard of a 5" being carried, though it may have been in the Cold War days.....I'm sure it prob got certified at some point for the A-D Hornet. The pods we carried, whatever they were designated (would have to look that up), were built for a 2.75 round. As an aside, the SH could also not carry the LUU-2 or the cargo/blivet pod (a modified napalm canister I was told). On the first account, I remember being a LUU-2 "truck" for a mixed flight of C/E's shooting Sidewinders in a missile shoot. Rhinos couldn't carry so I had to drop the LUU-2 target for them and then get the hell out of the way. When I came to me, I dropped, switched to A/A master mode (from A/G to drop the flare), did a high speed burner 360 and then hosed a sidewinder at my own flare a few seconds later. Hah that was fun. On the second account, cross countries in the E/F aren't as convenient without the blivet to carry your bag. We also didn't have an empty 14R door (which the Hornet had) to throw stuff into.

The "NATOPS" manual you refer to I assume is actually the NATIP. Not a lot of stores related info in the NATOPS.

Re: Comparison by Spurts

Unread postPosted: 18 Aug 2020, 10:49
by sprstdlyscottsmn
Just weight and drag info at the beginning of the Perf sheets. Nothing on carriage/employment/G limits.

Re: Comparison by Spurts

Unread postPosted: 18 Aug 2020, 12:01
by madrat
That is pretty interesting about rocket options on Hornet/SH being so limited.

Consider how frequent Flankers are shown shooting masses of unguided rockets. Might be fine if nobody is shooting back but I cannot imagine you go into a zone with active MANPADS and these rockets being a good idea. That's why it is easy to dismiss APKWS being employed from super duper fighters when you could launch them from cheap drones or helicopters built to that task. Why risk your assets?

Re: Comparison by Spurts

Unread postPosted: 18 Aug 2020, 13:06
by sprstdlyscottsmn
I was planning on using LZuni for SHornet and APKWS for Viper for the CAS mission. Why? Because a single pylon would thus carry 8-19 forward firing, high speed, precision (hit a person though a window precision) munitions with a small danger-close factor. It could be targeted with the nose pointed away and only requires the nose to be "close enough" for launch. It gives all the impressions of being the ideal CAS weapon for many scenarios. But alas, the LZuni turns out to be a USMC thing, not a USN thing. Is someone also going to tell me APKWS can't be used from a Viper? That would be a kick.

Re: Comparison by Spurts

Unread postPosted: 18 Aug 2020, 13:34
by madrat
I kind off like the basic premise of APKWS, but getting down in the mud is the last reason.

I see them as an asset that would help in the cruise missile intercept role. The same concept would be a nice ait policing option where you could precisely disable engines on a jet if necessary. Laser guided 20mm shells should be great, too, as they've demonstrated them on .50 cal. If you can one-shot one-kill with a 20mm on a cruise missile then APKWS maybe becomes unnecessary as a primary close-in cruise missile killer. Of course you would still want AIM-9 and AIM-120. But when those run out you don't get many bursts from your gun.

Re: Comparison by Spurts

Unread postPosted: 18 Aug 2020, 14:37
by sprstdlyscottsmn
I hear you, but CAS is one of my mission sets I am reviewing. Cruise missile intercept is not. So while I agree with you that APKWS is a very flexible sounding weapon I am more concerned about what to do for the F/A-18E for the CAs mission (where I use the heaviest, draggiest, most numerous munitions). I could go with SDB IIs for numbers, or twin racked GBU-32s for weight and drag, but that is way too much boom for CAS IMO.

Re: Comparison by Spurts

Unread postPosted: 18 Aug 2020, 17:21
by marauder2048
sprstdlyscottsmn wrote:I hear you, but CAS is one of my mission sets I am reviewing. Cruise missile intercept is not. So while I agree with you that APKWS is a very flexible sounding weapon I am more concerned about what to do for the F/A-18E for the CAs mission (where I use the heaviest, draggiest, most numerous munitions). I could go with SDB IIs for numbers, or twin racked GBU-32s for weight and drag, but that is way too much boom for CAS IMO.


AGM-65 or any other AGM with a warhead <= 300 lbs.
The danger close figure for APKWS is 95m vs. AGM-65 which is 100m.

Re: Comparison by Spurts

Unread postPosted: 18 Aug 2020, 18:56
by sprstdlyscottsmn
marauder2048 wrote:AGM-65 or any other AGM with a warhead <= 300 lbs.
The danger close figure for APKWS is 95m vs. AGM-65 which is 100m.

Excellent suggestion. I may have to give up on my goal of having the CAS loadout be the same as the MGTOW and highest DI possible load. Thanks again.

Re: Comparison by Spurts

Unread postPosted: 18 Aug 2020, 19:29
by eagle3000
35_aoa wrote:On the point of the LAU-10, my *google* search yields that is pod for the 5" ZUNI. We only carried the 2.75" Hydra in the Hornet, never heard of a 5" being carried, though it may have been in the Cold War days.....I'm sure it prob got certified at some point for the A-D Hornet.


Certified and used by the USMC.
Here's one from Desert Storm: https://www.dstorm.eu/pictures/nose-art ... 4064_2.jpg
And more recent: https://www.jetphotos.com/photo/7490712

Re: Comparison by Spurts

Unread postPosted: 19 Aug 2020, 08:13
by 35_aoa
eagle3000 wrote:Certified and used by the USMC.
And more recent: https://www.jetphotos.com/photo/7490712


Hah nice, leave it to the Marines!

Re: Comparison by Spurts

Unread postPosted: 19 Aug 2020, 16:17
by sprstdlyscottsmn
I found a picture of a SHornet with a MER. Is that only for the tiny training bombs?

Re: Comparison by Spurts

Unread postPosted: 20 Aug 2020, 00:51
by madrat

Re: Comparison by Spurts

Unread postPosted: 20 Aug 2020, 07:39
by 35_aoa
sprstdlyscottsmn wrote:I found a picture of a SHornet with a MER. Is that only for the tiny training bombs?


Both Hornet and SH use BRU-41 / IMER for mk76 and LGTR/LGTRII carriage these days.....ie your typical lightweight inert training ordnance. And yes, other than LUU-2, I can't think of much else they are used for.

Re: Comparison by Spurts

Unread postPosted: 20 Aug 2020, 11:13
by sprstdlyscottsmn
That's what I figured, thanks for confirming.

Re: Comparison by Spurts

Unread postPosted: 20 Aug 2020, 12:37
by madrat
Best I could find F/A-18 with IMER

https://nara.getarchive.net/media/priva ... ?zoom=true

and

Image

Re: Comparison by Spurts

Unread postPosted: 20 Aug 2020, 15:54
by disconnectedradical
Wouldn't Super Hornet have issues with rocket pods due to the way the pylons are canted outwards? I suppose they can modify the mounting system or have a special adapter, but I would imagine that's extra weight.

Re: Comparison by Spurts

Unread postPosted: 20 Aug 2020, 16:04
by sprstdlyscottsmn
disconnectedradical wrote:Wouldn't Super Hornet have issues with rocket pods due to the way the pylons are canted outwards? I suppose they can modify the mounting system or have a special adapter, but I would imagine that's extra weight.

That's what was discussed earlier. I assumed, incorrectly, that the weapon computer just moved the pipper on the HUD a few degrees off center since rocket pods were listed in the NATOPS, but I was corrected by 35_aoa.

Re: Comparison by Spurts

Unread postPosted: 28 Sep 2020, 13:54
by sprstdlyscottsmn
Okay, the Super Hornet is finished for now. I need to go back and fix the F-16s loadouts for the AG missions, then I move on to the Typhoon.

Re: Comparison by Spurts

Unread postPosted: 29 Sep 2020, 04:48
by eloise
sprstdlyscottsmn wrote:Okay, the Super Hornet is finished for now. I need to go back and fix the F-16s loadouts for the AG missions, then I move on to the Typhoon.

:D super hornet seem to take less time than F-16?

Re: Comparison by Spurts

Unread postPosted: 29 Sep 2020, 10:57
by sprstdlyscottsmn
It did. Which was very surprising to me.

Re: Comparison by Spurts

Unread postPosted: 29 Sep 2020, 14:46
by eloise
Consider the range and speed of Meteor, it is such a shame that it can't be used for air to ground role

Re: Comparison by Spurts

Unread postPosted: 29 Sep 2020, 16:03
by sprstdlyscottsmn
eloise wrote:Consider the range and speed of Meteor, it is such a shame that it can't be used for air to ground role


That body with an AESA seeker, multimode/multimission programing, multipurpose warhead. Could be neat. In the meantime, I need to get the F-16 redone for CAS and maybe deep strike too.

Re: Comparison by Spurts

Unread postPosted: 30 Sep 2020, 06:57
by hornetfinn
eloise wrote:Consider the range and speed of Meteor, it is such a shame that it can't be used for air to ground role


What targets do you see for that kind of missile? It has quite small warhead and seeker and fuze are not well suited against small ground targets. With another seeker and new software it might be usable against SAM firecontrol radars but I'm not sure anybody would bother developing that when there is AARGM-ER available.

How about surface-to-air version of Meteor? It would need a booster and other upgrades, but it would likely have pretty impressive performance for such a small missile. Of course there are already missiles like ESSM Block 2, CAMM-ER, Barak 8 and Stunner/Skyceptor available.

Re: Comparison by Spurts

Unread postPosted: 30 Sep 2020, 07:53
by eloise
hornetfinn wrote:What targets do you see for that kind of missile? It has quite small warhead and seeker and fuze are not well suited against small ground targets. With another seeker and new software it might be usable against SAM firecontrol radars but I'm not sure anybody would bother developing that when there is AARGM-ER available

Mainly SAM fire control or search radar. There are AARGM-ER available but you can't carry as many AARGM-ER as Meteor and with a ramjet engine, Meteor can sustain high supersonic speed for longer period of time.

Re: Comparison by Spurts

Unread postPosted: 30 Sep 2020, 09:06
by hornetfinn
eloise wrote:
hornetfinn wrote:What targets do you see for that kind of missile? It has quite small warhead and seeker and fuze are not well suited against small ground targets. With another seeker and new software it might be usable against SAM firecontrol radars but I'm not sure anybody would bother developing that when there is AARGM-ER available

Mainly SAM fire control or search radar. There are AARGM-ER available but you can't carry as many AARGM-ER as Meteor and with a ramjet engine, Meteor can sustain high supersonic speed for longer period of time.


I can definitely see the advantages of such a missile. I think it might well be possible with advanced AESA seeker which could act both in anti-radiation and radar modes. With GaN technology it should have pretty impressive bandwith coverage, although definitely not anything like a dedicated missile like AARGM-ER. Even better would be if it also had IIR seeker for very high accuracy due to small warhead.

But anyway, these comparisons by spurts are really interesting. Than you spurts! I have to find some time to study them thorougly.

Re: Comparison by Spurts

Unread postPosted: 01 Oct 2020, 13:50
by sprstdlyscottsmn
Touch up of the F-16 is going to be delayed. Something broke in the wave drag calculation when I had to modify it for the SHornet. I thought my modification was compatible with my F-15/16 model data, but apparently not.

Re: Comparison by Spurts

Unread postPosted: 02 Oct 2020, 09:14
by eloise
sprstdlyscottsmn wrote:Touch up of the F-16 is going to be delayed. Something broke in the wave drag calculation when I had to modify it for the SHornet. I thought my modification was compatible with my F-15/16 model data, but apparently not.

The complexity and details of your estimation is unbelieveable

Re: Comparison by Spurts

Unread postPosted: 02 Oct 2020, 11:58
by sprstdlyscottsmn
I was able to fix it. Now I am re doing CAS and then I'm all set to start the Tiffy.

Re: Comparison by Spurts

Unread postPosted: 06 Oct 2020, 04:46
by eloise
The aero heating of Meteor is 500°C for a few minutes that mean cruising speed around Mach 3.5 for 3-4 minutes ?
motor burn time.PNG

stagnant-temperature-1.png

Re: Comparison by Spurts

Unread postPosted: 06 Oct 2020, 04:51
by eloise
Su-35 test launch R-37M a few days ago:

EjZ473YUYAAvGL-.jpg

EjZ48bzUcAITHld.jpg

Re: Comparison by Spurts

Unread postPosted: 06 Oct 2020, 11:18
by sprstdlyscottsmn
Interesting implication that the ASRAAM hits Mach4+

Re: Comparison by Spurts

Unread postPosted: 06 Oct 2020, 11:36
by hornetfinn
sprstdlyscottsmn wrote:Interesting implication that the ASRAAM hits Mach4+


True. Maybe the cooling is so good that aerodynamic heating of dome material is not a problem even at those speeds?

Re: Comparison by Spurts

Unread postPosted: 06 Oct 2020, 17:37
by wrightwing
eloise wrote:


Mainly SAM fire control or search radar. There are AARGM-ER available but you can't carry as many AARGM-ER as Meteor and with a ramjet engine, Meteor can sustain high supersonic speed for longer period of time.

What basis are you using to suggest that Meteor is faster (or faster longer) than AARGM-ER? You do realize that AARGM-ER, not only out ranges Meteor by several hundred kilometers, but is a high supersonic weapon as well. It also packs a much bigger punch. SPEAR3 or some variation would be a better option, than using your AAMs, as ARMs.

Re: Comparison by Spurts

Unread postPosted: 06 Oct 2020, 17:46
by madrat
hornetfinn wrote:
sprstdlyscottsmn wrote:Interesting implication that the ASRAAM hits Mach4+


True. Maybe the cooling is so good that aerodynamic heating of dome material is not a problem even at those speeds?

Python 4 + Python V used manufactured emerald glass as seeker dome to attain much higher velocities than seeker on the Sidewinders. Maybe they did that for AIM-132.

Re: Comparison by Spurts

Unread postPosted: 06 Oct 2020, 23:41
by marauder2048
madrat wrote:
hornetfinn wrote:
sprstdlyscottsmn wrote:Interesting implication that the ASRAAM hits Mach4+


True. Maybe the cooling is so good that aerodynamic heating of dome material is not a problem even at those speeds?

Python 4 + Python V used manufactured emerald glass as seeker dome to attain much higher velocities than seeker on the Sidewinders. Maybe they did that for AIM-132.


They're upgrading AIM-9X dome material from Sapphire to Nano Composite Optical Ceramic.
From memory, it's supposed to be Lot 20 (FY2020) and up.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 07:45
by hornetfinn
marauder2048 wrote:
madrat wrote:
hornetfinn wrote:True. Maybe the cooling is so good that aerodynamic heating of dome material is not a problem even at those speeds?

Python 4 + Python V used manufactured emerald glass as seeker dome to attain much higher velocities than seeker on the Sidewinders. Maybe they did that for AIM-132.


They're upgrading AIM-9X dome material from Sapphire to Nano Composite Optical Ceramic.
From memory, it's supposed to be Lot 20 (FY2020) and up.


Very interesting, thank you. Here is interesting presentation about Nano-Composite Optical Ceramics:
https://apps.dtic.mil/dtic/tr/fulltext/u2/a527006.pdf

Looks like NCOC material combines the best qualities of previous materials used in IR domes but with better thermal shock resistance than any one of the other materials. Sapphire has been the best material previously, but this seems to significantly outperform it in all metrics.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 09:06
by hornetfinn
More detailed info about Nano-Composite Optical Ceramics properties:
https://www.researchgate.net/publicatio ... ocomposite

The strength of the nanocomposite at 21°C is twice as great as strengths achieved for its constituents


M:Y has ~80% infrared transmittance at 4–6 lm wavelengths, with five times less absorption than spinel and ten times less absorption than c-plane sapphire at 4.85 lm.


Sounds pretty good results to me.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 15:28
by mixelflick
eloise wrote:Su-35 test launch R-37M a few days ago:

EjZ473YUYAAvGL-.jpg

EjZ48bzUcAITHld.jpg


This missile is far more interesting than the new K-77 IMO, if not anywhere near as practical. 400KM range, flies at mach 6, 60kg warhead..... are the brochure figures. Wonder what the real world stats are?

I used to think the R-33 was big, but this monster actually dwarfs it. Has to cost a pretty penny, I wonder how many platforms they'll end up equipping with it. Supposedly Mig-31, SU-35, SU-30SM's and the Mig-35.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 18:57
by eloise
wrightwing wrote:What basis are you using to suggest that Meteor is faster (or faster longer) than AARGM-ER? You do realize that AARGM-ER, not only out ranges Meteor by several hundred kilometers, but is a high supersonic weapon as well. It also packs a much bigger punch. SPEAR3 or some variation would be a better option, than using your AAMs, as ARMs.

I think AARGM_ER has higher top speed and probably better acceleration. But Meteor can sustain high supersonic for longer period of time thanks to its ability to throttle back in cruise condition. Spurt has done some simulation and clearly Meteor is quite unrivaled at long range.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 19:17
by sprstdlyscottsmn
All non-"Wiki" type info I found on the Meteor tells me that the ">100km" is vastly conservative. I don't see a purpose of an A-G Meteor vs the AARGM-ER for SEAD.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 19:43
by marauder2048
eloise wrote:I think AARGM_ER has higher top speed and probably better acceleration. But Meteor can sustain high supersonic for longer period of time thanks to its ability to throttle back in cruise condition. Spurt has done some simulation and clearly Meteor is quite unrivaled at long range.


It really can't throttle-back since the gas generator is always burning and due to deposits from the gas generator
and the valve heating up it become less effective in regulating the burn rate.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 20:15
by sprstdlyscottsmn
marauder2048 wrote:It really can't throttle-back since the gas generator is always burning and due to deposits from the gas generator
and the valve heating up it become less effective in regulating the burn rate.

Can you provide a source? Everything I have seen about the throttling implies a 10:1 throttle ability and that the air-breathing gives it 3X the effective ISP of normal rocket motors.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 20:20
by marauder2048
sprstdlyscottsmn wrote:
marauder2048 wrote:It really can't throttle-back since the gas generator is always burning and due to deposits from the gas generator
and the valve heating up it become less effective in regulating the burn rate.

Can you provide a source? Everything I have seen about the throttling implies a 10:1 throttle ability and that the air-breathing gives it 3X the effective ISP of normal rocket motors.


Pat Hewitt's dissertation (*drool*) on GQM-163:

https://vtechworks.lib.vt.edu/handle/10919/28928


You do see some wild maximum turn-down claims out there but I don't believe those to
be representative of steady-state capability.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 21:29
by sprstdlyscottsmn
marauder2048 wrote:
Pat Hewitt's dissertation (*drool*) on GQM-163:

https://vtechworks.lib.vt.edu/handle/10919/28928


You do see some wild maximum turn-down claims out there but I don't believe those to
be representative of steady-state capability.


Thanks for that, it was fascinating and I would like to be able to read it in more depth later. Some things I noticed, the study was about different nozzle types and did not appear to test the results of throttling at all, so I don't see anything that would contradict the 10:1 statement. Specifically on p59, "All three tests are near the same throttle setting and fuel flowrate during this time so the effects of equivalence ratio are removed and the differences in combustion efficiency reduce to injector design. "

Your statement about unburnt deposits and valve heating making the regulation less effective do not actually contradict the 10:1 throttle range statement, only shows how difficult it would be/was to do so.

In order for me to change my model I need numbers, not "I don't believe" statements. I welcome being corrected, and I admit that search for the throttle range these days all seems to have a regurgitation of the same data on Wiki, word for word, and the Wiki does not list a source either. If I can't find one I may change the ratio to 3:1, or whatever allows 5-mintues of flight (as I saw in another article about a test shot from a Grippen).

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 21:55
by marauder2048
sprstdlyscottsmn wrote:
marauder2048 wrote:
Pat Hewitt's dissertation (*drool*) on GQM-163:

https://vtechworks.lib.vt.edu/handle/10919/28928


You do see some wild maximum turn-down claims out there but I don't believe those to
be representative of steady-state capability.


Thanks for that, it was fascinating and I would like to be able to read it in more depth later. Some things I noticed, the study was about different nozzle types and did not appear to test the results of throttling at all, so I don't see anything that would contradict the 10:1 statement. Specifically on p59, "All three tests are near the same throttle setting and fuel flowrate during this time so the effects of equivalence ratio are removed and the differences in combustion efficiency reduce to injector design. "

Your statement about unburnt deposits and valve heating making the regulation less effective do not actually contradict the 10:1 throttle range statement, only shows how difficult it would be/was to do so.



I guess sensitivity analysis isn't you thing..

The study was not about different nozzle types; it was about different fuel additives to promote better combustion
due to the limited volume available for low L/D combustion chambers.

And it was based on GQM-163 flight and ground test data.

Naturally, a non-integral rocket ramjet can play more tricks since it's not compromised by having to
accommodate the booster.

Where is the source of the "10:1 statement ?" The main consequence of valve expansion
would be the reduce the low-end of the turn-down i.e. you can't throttle down as efficiently.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 22:14
by sprstdlyscottsmn
marauder2048 wrote:
I guess sensitivity analysis isn't you thing..

The study was not about different nozzle types; it was about different fuel additives to promote better combustion
due to the limited volume available for low L/D combustion chambers.

And it was based on GQM-163 flight and ground test data.

Naturally, a non-integral rocket ramjet can play more tricks since it's not compromised by having to
accommodate the booster.

Where is the source of the "10:1 statement ?" The main consequence of valve expansion
would be the reduce the low-end of the turn-down i.e. you can't throttle down as efficiently.


Sorry, I guess I misread something. I thought I saw the D1 D2 D3 being different nozzle types. It was a long document and I didn't have the hours to read it that it would take. I did gather that it was about matching predictions to tests data.

I said in my last post that in trying to find the source again all I get are word-for-word copies of Wiki and Wiki has no source, so I am inclined to reduce the 10:1 to a value that still fits with the Meteor flight test results for time of powered flight.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 22:37
by marauder2048
Per Janes International Defense Review (1/1994), the requirement is a turn-down ratio of 6:1.

Re: Comparison by Spurts

Unread postPosted: 07 Oct 2020, 23:15
by sprstdlyscottsmn
Thanks! I'll give that a shot and see what happens

Edit: 6:1 yields a higher average and peak speed, earlier motor burnout, and reduced terminal velocity at the same range the old model reached in 300s, but this one took less time due to higher average speed.

Re: Comparison by Spurts

Unread postPosted: 08 Oct 2020, 02:41
by eloise
This could be of interest
MA-31 advantage.jpg

Re: Comparison by Spurts

Unread postPosted: 08 Oct 2020, 03:25
by marauder2048
eloise wrote:This could be of interest
MA-31 advantage.jpg


Kh-31 is a liquid fueled ramjet and was replaced by the GQM-163 which is a VFDR.
The best data on VFDRs comes from the GQM-163.

The US sincerely hopes that the Kh-31 is representative of Russian supersonic weaponry
since it was an awful POS.

Re: Comparison by Spurts

Unread postPosted: 08 Oct 2020, 04:37
by eloise
marauder2048 wrote:The US sincerely hopes that the Kh-31 is representative of Russian supersonic weaponry
since it was an awful POS.

Why is it awful?
It is faster than any antiship in US inventory and can sea skimming at Mach 2.7, then the 15G maneuver

Re: Comparison by Spurts

Unread postPosted: 08 Oct 2020, 06:59
by marauder2048
eloise wrote:
marauder2048 wrote:The US sincerely hopes that the Kh-31 is representative of Russian supersonic weaponry
since it was an awful POS.

Why is it awful?
It is faster than any antiship in US inventory and can sea skimming at Mach 2.7, then the 15G maneuver


It wasn't an anti-ship missile; it was an ARM which really made it unsuited to be a ASCM surrogate.


To hear the Boeing engineers tell it, the missile as acquired did not work. With extensive effort
it was made to work but not reliably. But it was cheap and after the collapse of the Soviet Union, available.
And it was dumped as soon as Orbital got GQM-163 working.

Re: Comparison by Spurts

Unread postPosted: 09 Oct 2020, 05:28
by eloise
marauder2048 wrote:Per Janes International Defense Review (1/1994), the requirement is a turn-down ratio of 6:1.

Is that the requirement for Meteor or the FMRAAM program?
Do you have the screenshot of the supposed paragraph?

Re: Comparison by Spurts

Unread postPosted: 09 Oct 2020, 05:42
by eloise
marauder2048 wrote:It wasn't an anti-ship missile; it was an ARM which really made it unsuited to be a ASCM surrogate.
To hear the Boeing engineers tell it, the missile as acquired did not work. With extensive effort
it was made to work but not reliably. But it was cheap and after the collapse of the Soviet Union, available.
And it was dumped as soon as Orbital got GQM-163 working.

I haven't read anything about that, but I think it mostly due to the unreliable seeker.
The propulsion is still much better than HARMs, I don't think US currently have any fighter launched missile with better kinematic than KH-31

Re: Comparison by Spurts

Unread postPosted: 09 Oct 2020, 06:07
by marauder2048
eloise wrote:
marauder2048 wrote:Per Janes International Defense Review (1/1994), the requirement is a turn-down ratio of 6:1.

Is that the requirement for Meteor or the FMRAAM program?
Do you have the screenshot of the supposed paragraph?


It was for A3M which became Meteor. I don't have a screenshot and wouldn't post it if I did
because it's copyrighted material.

Re: Comparison by Spurts

Unread postPosted: 09 Oct 2020, 06:11
by marauder2048
eloise wrote:
marauder2048 wrote:I haven't read anything about that, but I think it mostly due to the unreliable seeker.
The propulsion is still much better than HARMs, I don't think US currently have any fighter launched missile with better kinematic than KH-31


AFAIK, they never used the original seeker in target testing.

The US does have a ground-launched missile in the form of GQM-163 which can mimic
all four supersonic threat types.

The MA-31 was only good for mimicking one...barely.

Re: Comparison by Spurts

Unread postPosted: 09 Oct 2020, 17:34
by garrya
marauder2048 wrote:Per Janes International Defense Review (1/1994), the requirement is a turn-down ratio of 6:1.

sprstdlyscottsmn wrote:Thanks! I'll give that a shot and see what happens
Edit: 6:1 yields a higher average and peak speed, earlier motor burnout, and reduced terminal velocity at the same range the old model reached in 300s, but this one took less time due to higher average speed.

AFAIK the demonstration value is 9:1
1.PNG

Meteor 2.PNG

Re: Comparison by Spurts

Unread postPosted: 09 Oct 2020, 18:25
by marauder2048
garrya wrote:
marauder2048 wrote:Per Janes International Defense Review (1/1994), the requirement is a turn-down ratio of 6:1.

sprstdlyscottsmn wrote:Thanks! I'll give that a shot and see what happens
Edit: 6:1 yields a higher average and peak speed, earlier motor burnout, and reduced terminal velocity at the same range the old model reached in 300s, but this one took less time due to higher average speed.

AFAIK the demonstration value is 9:1


Which, as is clear from your own source, this wasn't the requirement.

Re: Comparison by Spurts

Unread postPosted: 10 Oct 2020, 05:34
by garrya
marauder2048 wrote:Which, as is clear from your own source, this wasn't the requirement.

I know, I'm trying to say that while the requirement is only 6:1, they actually demonstrated 9:1 with their design. In other words, the real throttle ratio excess the requirement.

Re: Comparison by Spurts

Unread postPosted: 10 Oct 2020, 12:53
by sprstdlyscottsmn
And yet I find that with the 300s time limit 6:1 allows greater range than 10:1. I'm going to do an analysis to see what throttle ratio is best for a given intercept range.

Re: Comparison by Spurts

Unread postPosted: 10 Oct 2020, 17:21
by eloise
sprstdlyscottsmn wrote:And yet I find that with the 300s time limit 6:1 allows greater range than 10:1.

Isn't that obvious?
If I understand it correctly, the main reason for high throttle back ratio is to conserve fuel and increase burn time. But high throttle back ratio also mean lower minimum thrust. So if the total burn time is a constant then higher throttle back ratio will allow less range.

Re: Comparison by Spurts

Unread postPosted: 10 Oct 2020, 19:26
by marauder2048
garrya wrote:
marauder2048 wrote:Which, as is clear from your own source, this wasn't the requirement.

I know, I'm trying to say that while the requirement is only 6:1, they actually demonstrated 9:1 with their design. In other words, the real throttle ratio excess the requirement.


At that point, 9:1 was a laboratory demonstration. That's where you typically see those high figures.
6:1 or maybe 7.5:1 is what's typically attainable in flight.

eloise wrote:
sprstdlyscottsmn wrote:And yet I find that with the 300s time limit 6:1 allows greater range than 10:1.

Isn't that obvious?
If I understand it correctly, the main reason for high throttle back ratio is to conserve fuel and increase burn time. But high throttle back ratio also mean lower minimum thrust. So if the total burn time is a constant then higher throttle back ratio will allow less range.


I'm not sure how this is being modeled but a higher turndown ratio should always produce better range.
Particularly in lofts.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a257018.pdf

Re: Comparison by Spurts

Unread postPosted: 10 Oct 2020, 21:18
by sprstdlyscottsmn
300s was a battery power limit. At 10:1 the motor was laying almost the whole time. At 6:1 the motor was burning out much sooner but the higher average speed meant it went further in 300s

Re: Comparison by Spurts

Unread postPosted: 10 Oct 2020, 22:06
by marauder2048
sprstdlyscottsmn wrote:300s was a battery power limit. At 10:1 the motor was laying almost the whole time. At 6:1 the motor was burning out much sooner but the higher average speed meant it went further in 300s


Quite why a missile with the putative range would rely on battery power rather than an
alternator (see PGK, SDB II) is strange.

A big gain from higher TDR is reduced overspeeding at altitude which is really important to the radome.

And the state-of-the-art for batteries 6 years ago doesn't seem like a big ask for > 300 seconds flight time.

https://www.navysbir.com/n14_2/N142-092.htm

Re: Comparison by Spurts

Unread postPosted: 11 Oct 2020, 03:18
by madrat
Solidstate capacitor storage would better fit the role.

Re: Comparison by Spurts

Unread postPosted: 11 Oct 2020, 04:08
by marauder2048
madrat wrote:Solidstate capacitor storage would better fit the role.

They tend not to like the very low temperatures where external stores have to operate.

Though I suppose there's nothing preventing the weapons station from charging/heating them up
prior to launch.

Re: Comparison by Spurts

Unread postPosted: 11 Oct 2020, 15:45
by sprstdlyscottsmn
Okay so I just ran the TDR vs time-to-range analysis.

Constants:
    launch airspeed - M1.0
    launch altitude - 36,000ft
    target altitude - 36,000ft
    target speed - M0.0 (used to control the impact point)
    max electrical power - 300s
    minimum powered flight speed - 1.9M (throttle will not reduce below what is needed to sustain this speed)
    loft - 4 deg to a max alt of 85,000ft to feed motor enough oxygen (this alt not reached in this test before turn down to intercept)
    total weight - 419lb
    total fuel weight - 143lb
    effective ISP - 795s
    Boost - 2s @ 5600lb
    Sustain - 30s @ 2662lb (TDR 1:1)
    Lift Area - 4.8ft^2
    Drag Area - 0.31ft^2 (zero lift)

Variables:
    TDR - 1-10 in whole numbers
    target impact distance (TID)

Throttle logic: When time-to-impact is less than or equal to remaining motor duration at full thrust, full thrust. Otherwise the maximum value of minimum throttle or thrust required to sustain minimum powered flight speed (as missile climbs in loft this will switch from MPFS to MinT depending on TDR.

Results by TDR:
    1 - range is aero limited (stall) at 70nm, best for TID between 0 and 52nm
    2 - range is aero limited (stall) at 96nm, best for TID between 52 and 73nm
    3 - range is time limited at 112nm, best for TID between 73 and 93nm
    4 - range is time limited at 124nm, best for TID between 93 and 111nm
    5 - range is time limited at 132nm, best for TID between 111 and 127nm
    6 - range is time limited at 136nm, best for TID between 127 and xxxnm
    7 - range is time limited at 128nm, never best under the current time constraint
    8 - range is time limited at 123nm, never best under the current time constraint, still under power at impact
    9 - range is time limited at 121nm, never best under the current time constraint, still under power at impact
    10 - range is time limited at 119nm, never best under the current time constraint, still under power at impact

This model was built before the above information about boost phase time and speed. Boost motor stats can be changed to reflect this and MPFS can be adjusted as well, this will reduce all ranges. Loft can be increased to extend ranges.

Re: Comparison by Spurts

Unread postPosted: 11 Oct 2020, 20:14
by marauder2048
sprstdlyscottsmn wrote:Okay so I just ran the TDR vs time-to-range analysis.

Is there really evidence that powered flight is possible below Mach 2?
The paper indicates Mach 2.5 is about the minimum powered flight Mach.

And Max thrust doesn't take into account the restrictions on radome heating.

While I appreciate your modeling efforts; the table above from the paper gives
the appropriate and IMHO more convincing data points.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 02:03
by sprstdlyscottsmn
You didn't read until the end did you?

sprstdlyscottsmn wrote:This model was built before the above information about boost phase time and speed. Boost motor stats can be changed to reflect this and MPFS can be adjusted as well, this will reduce all ranges. Loft can be increased to extend ranges.

I built this flight model over about two years ago, I saw the paper you referenced yesterday. In the effort of a reduction analysis I was using my model as was and only playing with TDR. I figured you would be able to appreciate that, since I specifically addressed your concerns at the end of my post.

I don't mean to sound ungrateful, because I am very grateful for the information provided. The next thing I will be doing is updating the minimum speed to 3.0M based on the TDR 5 and TDR 10 data shown and improving the boost phase to reach 2.5M from the minimum launch conditions. I will also try to implement a maximum speed of 4.0M. If you have anything concrete about max electrical power time I will happily take that too, otherwise I will be sticking with 300s.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 02:30
by sprstdlyscottsmn
This is all coming at the perfect time because I am about the start the Typhoon, which will be the first Meteor equipped plane in the comparison.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 02:44
by marauder2048
sprstdlyscottsmn wrote:You didn't read until the end did you?


There's really no need since the scholarly, peer-reviewed paper has actual data points.
So I don't have to trust the vagaries of your modeling which seems to have a predilection
for unsourced magic numbers.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 03:10
by garrya
marauder2048 wrote:There's really no need since the scholarly, peer-reviewed paper has actual data points.
So I don't have to trust the vagaries of your modeling which seems to have a predilection
for unsourced magic numbers.

Discussion about the accuracy of Spurt analysis is fine and I think it is helpful to contribute better data points that you have but that aggressive tone is uncalled for.
After all, Spurt done all this analysis and calculation by himself. Not only it takes a lot of time, he also done that for free.
A little appreciation is better.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 03:40
by madrat
There is sufficient motivation not to publish everything about a weapon system capability. Spurts gives us insight to what could be possible. In no way is he going to leak secrets just to show off here. The attack on his credibility is absurd considering you offer zero to refute his numbers. Absolutely nothing.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 03:50
by f-16adf
X2, Spurts puts a considerable amount of time/effort into his work.

We should all appreciate that-

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 04:34
by marauder2048
madrat wrote:There is sufficient motivation not to publish everything about a weapon system capability. Spurts gives us insight to what could be possible. In no way is he going to leak secrets just to show off here. The attack on his credibility is absurd considering you offer zero to refute his numbers. Absolutely nothing.


Some of his numbers were sourced from wikipedia.
Some of them seem to be magically generated or nonsensical. Ex: a 4 degree loft angle.
Some of them have minima and maxima that are physically irrational. Ex: the low-end Mach no. for powered flight.

If I've got peer-reviewed, scholarly sources from practitioners in the field, I tend to favor their numbers
especially because they do sensitivity analysis and there's intuition provided.

If others find his approach useful then that's fine.
But he's a bit dogmatic about his numbers and his approach. And the scholarly sources are more comprehensive.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 13:47
by sprstdlyscottsmn
I would like to say there is nothing dogmatic or magical about my numbers. I do not choose them with an agenda. I take what values I can from official public information first, anecdotal public information second, Wikipedia as a last resort. For other things I have to take a best guess.

When someone tells me that my numbers are wrong and can provide evidence, as Marauder2048 did, I change my numbers to match the evidence.

Now, marauder2048 has an opinion of me, and my work, that saddens me but I am not going to try and force him to "see it my way" or anything of the sort. They have already shown themselves to be dismissive of my efforts and admittedly does not read my posts to their conclusion where I address my results and the problems therein.

In the end, my take away from this interaction is that I now have better data for the Meteor model, so I am grateful that it happened and I thank marauder2048 for sharing with me.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 17:53
by garrya
marauder2048 wrote:Some of his numbers were sourced from wikipedia.
Some of them seem to be magically generated or nonsensical. Ex: a 4 degree loft angle.
Some of them have minima and maxima that are physically irrational. Ex: the low-end Mach no. for powered flight.

If I've got peer-reviewed, scholarly sources from practitioners in the field, I tend to favor their numbers
especially because they do sensitivity analysis and there's intuition provided.

If others find his approach useful then that's fine.
But he's a bit dogmatic about his numbers and his approach. And the scholarly sources are more comprehensive.

There is nothing wrong with favoring scholarly sources and there isn't anything wrong with calling out the accuracy of some number if you think they are wrong either. But being aggressive isn't necessary, and name calling isn't helpful for the quality of the discussion.
Keep in mind that we don't actually have any scholarly sources for the whole thing that Spurts is doing right now, which is comparing between Su-35, F-35, F-15EX, F-18E/F, F-16V, Typhoon, Rafale and also their weapons. He also done various scenarios for each aircraft. That is a massive amount of work that he doing ALONE and for FREE so that other enthusiasts like us can have something to enjoy. It is very easy to pick apart some details of a long analysis write up and say you should do this, you should do that. But to actually done the whole analysis ourselves is a whole different story, there is a lot of work to do and it is impossible to not make any mistake
Moreover, it is quite unfair to claim that his numbers are all magical or sourced from Wikipedia. Most of Spurt number involve aircraft are delivered from EM diagrams and flight manual. Then by calculation using well known formular. There is only a few one that he has to borrow from Wikipedia when there is no other choice.
Last but not least, I don't think Spurts is being dogmatic, you are not the first to challenge him about his number or approach. If you read his previous thread, you can see that me and many others challenge him all the time and he always happy to change with new information to make his comparison more accurate.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 18:16
by garrya
marauder2048 wrote:At that point, 9:1 was a laboratory demonstration. That's where you typically see those high figures.
6:1 or maybe 7.5:1 is what's typically attainable in flight.

What make 9:1 unattainable in flight though? Or what condition of flight that affect throttle ratio but can't be recreated in laboratory

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 18:42
by marauder2048
garrya wrote:
marauder2048 wrote:At that point, 9:1 was a laboratory demonstration. That's where you typically see those high figures.
6:1 or maybe 7.5:1 is what's typically attainable in flight.

What make 9:1 unattainable in flight though? Or what condition of flight that affect throttle ratio but can't be recreated in laboratory


I explained that above: valve expansion due to heating and accumulation of gas generator products on it.

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 18:45
by garrya
marauder2048 wrote:
garrya wrote:
marauder2048 wrote:At that point, 9:1 was a laboratory demonstration. That's where you typically see those high figures.
6:1 or maybe 7.5:1 is what's typically attainable in flight.

What make 9:1 unattainable in flight though? Or what condition of flight that affect throttle ratio but can't be recreated in laboratory


I explained that above: valve expansion due to heating and accumulation of gas generator products on it.

Why can't that be recreated in the lab?

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 19:06
by marauder2048
garrya wrote:Why can't that be recreated in the lab?


Why do we flight test aircraft and munitions?

Re: Comparison by Spurts

Unread postPosted: 12 Oct 2020, 19:11
by marauder2048
garrya wrote:Keep in mind that we don't actually have any scholarly sources for the whole thing that Spurts is doing right now,


Which misses the point: we do have scholarly sources for what he's doing now.
An abundance of them actually.

It's quite easy to find these sources and they completely contradict his modeling on this topic to date.
Which, in my view, makes the other modeling suspect.

Example: He completely misinterpreted Pat Hewitt's dissertation.

Re: Comparison by Spurts

Unread postPosted: 14 Oct 2020, 11:42
by garrya
marauder2048 wrote:Which misses the point: we do have scholarly sources for what he's doing now.
An abundance of them actually.
It's quite easy to find these sources and they completely contradict his modeling on this topic to date.
Which, in my view, makes the other modeling suspect.

We don't have scholarly sources for Meteor itself, only for ramjet missile, though I admit still pretty close. Nevertheless, it is still a very small tiny part of the whole thing he is trying to do and he does the whole thing alone in his free time. So, we can expect that he might miss something along the way, that why I said it is beneficial for the comparison when we contribute our information. But being aggressive is unnecessary and not very helpful, it is like complaining that the youtube sci fi movies made by a single content creator doesn't have the same level of CGI as a Hollywood movie with budget of billions and made by hundreds of people
marauder2048 wrote:Example: He completely misinterpreted Pat Hewitt's dissertation.

That dissertation is 118 pages long though

Re: Comparison by Spurts

Unread postPosted: 14 Oct 2020, 11:44
by garrya
sprstdlyscottsmn wrote:In the end, my take away from this interaction is that I now have better data for the Meteor model, so I am grateful that it happened and I thank marauder2048 for sharing with me.

Btw, this is useful for you:
Meteor simulation.PNG

Meteor range loft.PNG

Meteor conclusion.PNG

Their simulated air to air missile is very similar to Meteor
meteor.jpg

Re: Comparison by Spurts

Unread postPosted: 14 Oct 2020, 14:19
by sprstdlyscottsmn
Thanks garrya! The highlighted boxes and the figures will definitely help. I don't have access to any of my stuff this week so I hope I can get to this over the weekend.

Re: Comparison by Spurts

Unread postPosted: 17 Oct 2020, 20:57
by marauder2048
garrya wrote:We don't have scholarly sources for Meteor itself, only for ramjet missile, though I admit still pretty close.


We do have scholarly sources for VFDR missiles which model a Meteor-like configuration that I posted upthread that you merely regurgitate down thread. They contradict his modeling. That's enough.

garrya wrote:
marauder2048 wrote:Example: He completely misinterpreted Pat Hewitt's dissertation.

That dissertation is 118 pages long though


Which didn't prevent him from almost immediately commenting on it
while managing to completely misunderstand what it's about.

I'd be sympathetic to the page length if there weren't these sections called "abstract" and "introduction"