Race! US Fighter vs Concord

Military aircraft - Post cold war aircraft, including for example B-2, Gripen, F-18E/F Super Hornet, Rafale, and Typhoon.
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rowbeartoe

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Unread post21 Jul 2021, 22:19

Hi Everyone. I hope everyone is having a great day.

I'm curious if Any US Fighter could take off and land faster than the Concord on the famous New York to London flight (3,470 miles)? It's said the Concord would need about 3 hours vs the 747 which would take about 6 hours. The SR-71 did the run in about 2 hours but it didn't take off from New York but it had to refuel.

So could a clean F-16, F-15, F-35, F-22 etc with our without fuel tanks, with refueling (I think no matter what they would need to have air refuel) leave New York and arrive in London faster than the Concord?

https://www.wired.com/2010/09/0901sr-71 ... o%20cities.
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steve2267

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Unread post22 Jul 2021, 04:55

No.

The Concorde cruised at 2.0 Mach. So to beat that time, a fighter would need to fly faster than 2.0 Mach. To do so means the fighter would need to be clean (no external fuel tanks). But, to exceed 2.0 Mach, a fighter is going to be using reheat (i.e. afterburner(s)), which burns a LOT of gas really really quickly. For example, the F-15C has about 13,500lb of gas internally. In full afterburner, the F100 burns 1.94lb/lbf-hour. Using round numbers, with 24,000lb of thrust, and say 1.8 lb/lbf-hr, both F100s are going to be burning around 86,400lb of gas per hour, or 1,440lb of gas per minute. You'll be out of gas in about 10 minutes. Even if my numbers are off a bit, you're still going to be out of gas in a matter of tens of minutes. But you have to keep this speed up for three hours. And this does not even account for slowing down to get gas from an aerial tanker. (Slow down from 2.0+ Mach to 0.75 +/- Mach to tank, then accelerate back up to 2.0 Mach. But since you are flying slower than 2.0 Mach to tank, that means you are going to have to be going a lot faster than 2.0 Mach when not tanked, to make up for the lost time spent tanking.)

An F-22 can supercruise... but at 1.5 Mach -- not nearly fast enough to beat the Concorde, and reportedly only for about 460 +/- nautical miles.

So, no. A fighter could not beat the Concorde.
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basher54321

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Unread post22 Jul 2021, 15:17

Yeah Steve would be right - if the fuel capacity of over 200,000lbs is correct then that was probably a lot of available supersonic cruise time at altitude.

I think that fuel figure you have is for lower altitudes Steve so can probably shave quite a bit off that for the F100.

Looking at the SR-71 it had 80,000 lbs fuel capacity and at M3.2 @ 75,000ft the total fuel flow was estimated to be around 45,000 pph in Max burner.
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Unread post22 Jul 2021, 17:20

Concorde's engines were extremely efficient at high altitudes and supersonic speeds. In fact, the engines were capable of higer speeds, but the airframe was limited to M2.05. In testing, they achieved M2.23 and FL690.
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steve2267

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Unread post22 Jul 2021, 19:47

basher54321 wrote:Yeah Steve would be right - if the fuel capacity of over 200,000lbs is correct then that was probably a lot of available supersonic cruise time at altitude.

I think that fuel figure you have is for lower altitudes Steve so can probably shave quite a bit off that for the F100.

Looking at the SR-71 it had 80,000 lbs fuel capacity and at M3.2 @ 75,000ft the total fuel flow was estimated to be around 45,000 pph in Max burner.


Heck, I could be off by a factor of three, four or five... Insteada running outta gas in 10 minutes, it's 20, 30, or 40 minutes. When you're looking at a three hour flight, it don't matter -- you're not going to beat the Concorde, so the answer remains the same. (I just ran to Wikipedia to try to get in the SFC ballpark.)
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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aaam

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Unread post02 Aug 2021, 20:48

shadowhawk wrote:Concorde's engines were extremely efficient at high altitudes and supersonic speeds. In fact, the engines were capable of higer speeds, but the airframe was limited to M2.05. In testing, they achieved M2.23 and FL690.



...and Concorde supercruised, after afterburner was used to get up to M1.7.
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Unread post03 Aug 2021, 01:01

steve2267 wrote:For example, the F-15C has about 13,500lb of gas internally. In full afterburner, the F100 burns 1.94lb/lbf-hour. Using round numbers, with 24,000lb of thrust, and say 1.8 lb/lbf-hr, both F100s are going to be burning around 86,400lb of gas per hour, or 1,440lb of gas per minute. You'll be out of gas in about 10 minutes. Even if my numbers are off a bit, you're still going to be out of gas in a matter of tens of minutes.


Not far off. From the flight manual, for a clean F-15C:
Fuel flow at 2.0 Mach, 50k feet: 720 lbs/min
Fuel flow at 2.0 Mach, 30k feet: 1780 lbs/min

So if you hit the tanker, climb to 50k feet and accelerate, drop tanks, you can fly at 2.0 M for about 18 minutes.
That's about 380 nm? You'll actually make it to London. London, Ontario. :mrgreen:
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Unread post03 Aug 2021, 07:22

eagle3000 wrote:
steve2267 wrote:For example, the F-15C has about 13,500lb of gas internally. In full afterburner, the F100 burns 1.94lb/lbf-hour. Using round numbers, with 24,000lb of thrust, and say 1.8 lb/lbf-hr, both F100s are going to be burning around 86,400lb of gas per hour, or 1,440lb of gas per minute. You'll be out of gas in about 10 minutes. Even if my numbers are off a bit, you're still going to be out of gas in a matter of tens of minutes.


Not far off. From the flight manual, for a clean F-15C:
Fuel flow at 2.0 Mach, 50k feet: 720 lbs/min
Fuel flow at 2.0 Mach, 30k feet: 1780 lbs/min

So if you hit the tanker, climb to 50k feet and accelerate, drop tanks, you can fly at 2.0 M for about 18 minutes.
That's about 380 nm? You'll actually make it to London. London, Ontario. :mrgreen:


That doesn't factor in the fuel used to get to M2. You're not going to start your M2 sprint with 13,500lbs of fuel. Having spoken to an F-15 pilot, the fuel burn for a clean F-15 from ~M.8 to M2 is going to be ~8000lbs, and you're not getting above M1.6 with tanks (and your acceleration is going to be a lot slower and fuel burn higher, while you have them.)
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Corsair1963

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Unread post03 Aug 2021, 07:51

wrightwing wrote:
That doesn't factor in the fuel used to get to M2. You're not going to start your M2 sprint with 13,500lbs of fuel. Having spoken to an F-15 pilot, the fuel burn for a clean F-15 from ~M.8 to M2 is going to be ~8000lbs, and you're not getting above M1.6 with tanks (and your acceleration is going to be a lot slower and fuel burn higher, while you have them.)



Yes and we're talking about a clean F-15 too! :wink:
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Unread post03 Aug 2021, 11:53

wrightwing wrote:
eagle3000 wrote:
steve2267 wrote:For example, the F-15C has about 13,500lb of gas internally. In full afterburner, the F100 burns 1.94lb/lbf-hour. Using round numbers, with 24,000lb of thrust, and say 1.8 lb/lbf-hr, both F100s are going to be burning around 86,400lb of gas per hour, or 1,440lb of gas per minute. You'll be out of gas in about 10 minutes. Even if my numbers are off a bit, you're still going to be out of gas in a matter of tens of minutes.


Not far off. From the flight manual, for a clean F-15C:
Fuel flow at 2.0 Mach, 50k feet: 720 lbs/min
Fuel flow at 2.0 Mach, 30k feet: 1780 lbs/min

So if you hit the tanker, climb to 50k feet and accelerate, drop tanks, you can fly at 2.0 M for about 18 minutes.
That's about 380 nm? You'll actually make it to London. London, Ontario. :mrgreen:


That doesn't factor in the fuel used to get to M2. You're not going to start your M2 sprint with 13,500lbs of fuel. Having spoken to an F-15 pilot, the fuel burn for a clean F-15 from ~M.8 to M2 is going to be ~8000lbs, and you're not getting above M1.6 with tanks (and your acceleration is going to be a lot slower and fuel burn higher, while you have them.)


With "tanks" you mean bags, not CFTs?

What is the speed limit with CFTs?
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wrightwing

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Unread post03 Aug 2021, 18:55

hkultala wrote:





With "tanks" you mean bags, not CFTs?

What is the speed limit with CFTs?

Yes, I was referring to EFTs. CFTs are limited to M1.4, so they're not going to be useful for a M2 sprint.
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Unread post03 Aug 2021, 19:11

wrightwing wrote:Yes, I was referring to EFTs. CFTs are limited to M1.4, so they're not going to be useful for a M2 sprint.

CFT ordnance is limited to 1.4M on the F-15E. The CFT itself is good for 2.0M.
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eagle3000

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Unread post03 Aug 2021, 23:12

wrightwing wrote:That doesn't factor in the fuel used to get to M2. You're not going to start your M2 sprint with 13,500lbs of fuel. Having spoken to an F-15 pilot, the fuel burn for a clean F-15 from ~M.8 to M2 is going to be ~8000lbs, and you're not getting above M1.6 with tanks (and your acceleration is going to be a lot slower and fuel burn higher, while you have them.)


I used the fuel in the drop tanks to accelerate and climb away from the tanker to start the sprint with full internal fuel.
You can easily go above 1.6 M with tanks... if you overspeed the tanks. Since this is just for fun, I don't think it matters. The part I would be more worried about is punching the tank(s) at around 2 Mach... :D

I don't think you'll need all of 8000 lbs (two tanks), but a single tank (4000 lbs) is probably not enough. So two wing tanks. Now I worry a lot about the stabilisers... better use CFTs for this stunt. :mrgreen:
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wrightwing

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Unread post04 Aug 2021, 06:51

eagle3000 wrote:
wrightwing wrote:That doesn't factor in the fuel used to get to M2. You're not going to start your M2 sprint with 13,500lbs of fuel. Having spoken to an F-15 pilot, the fuel burn for a clean F-15 from ~M.8 to M2 is going to be ~8000lbs, and you're not getting above M1.6 with tanks (and your acceleration is going to be a lot slower and fuel burn higher, while you have them.)


I used the fuel in the drop tanks to accelerate and climb away from the tanker to start the sprint with full internal fuel.
You can easily go above 1.6 M with tanks... if you overspeed the tanks. Since this is just for fun, I don't think it matters. The part I would be more worried about is punching the tank(s) at around 2 Mach... :D

I don't think you'll need all of 8000 lbs (two tanks), but a single tank (4000 lbs) is probably not enough. So two wing tanks. Now I worry a lot about the stabilisers... better use CFTs for this stunt. :mrgreen:


I don't think you're going to be "speeding away" with 2 EFTs, especially with full internal fuel, and the fuel burn for the extra drag penalty, is going to be pretty high. You're also going to be burning fuel at a higher rate until you reach 50k, so it's not a steady state lb/minute. You won't get near M2 while the tanks are still on, or with CFTs.
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Unread post05 Aug 2021, 00:03

wrightwing wrote:I don't think you're going to be "speeding away" with 2 EFTs, especially with full internal fuel, and the fuel burn for the extra drag penalty, is going to be pretty high. You're also going to be burning fuel at a higher rate until you reach 50k, so it's not a steady state lb/minute. You won't get near M2 while the tanks are still on, or with CFTs.


Well there's the story of a fully armed 3 tanker reaching 1.8 M. So I think an unarmed 2 tanker can do 2.0 M.
Acceleration from 0.8 to 2 M with CFTs requires about 320 seconds at 40k feet.
Both a stretch? Sure. But probably not impossible.

Btw., the F-15F... I mean -EX got to Mach 2 during the 90 min first flight. While it has more powerful engines, it also has the draggier CFTs and it's heavier of course. And fuel apparently wasn't an issue.
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