Comparison by Spurts

New and old developments in aviation technology.
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sprstdlyscottsmn

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Unread post07 Oct 2020, 21:29

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).
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marauder2048

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Unread post07 Oct 2020, 21:55

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.
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sprstdlyscottsmn

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Unread post07 Oct 2020, 22:14

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.
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marauder2048

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Unread post07 Oct 2020, 22:37

Per Janes International Defense Review (1/1994), the requirement is a turn-down ratio of 6:1.
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sprstdlyscottsmn

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Unread post07 Oct 2020, 23:15

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.
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eloise

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Unread post08 Oct 2020, 02:41

This could be of interest
MA-31 advantage.jpg
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marauder2048

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Unread post08 Oct 2020, 03:25

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.
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eloise

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Unread post08 Oct 2020, 04:37

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
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marauder2048

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Unread post08 Oct 2020, 06:59

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.
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eloise

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Unread post09 Oct 2020, 05:28

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?
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eloise

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Unread post09 Oct 2020, 05:42

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
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marauder2048

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Unread post09 Oct 2020, 06:07

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.
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marauder2048

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Unread post09 Oct 2020, 06:11

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.
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garrya

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Unread post09 Oct 2020, 17:34

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
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marauder2048

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Unread post09 Oct 2020, 18:25

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.
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