Acceleration

Discuss the F-35 Lightning II
  • Author
  • Message
Offline
User avatar

playloud

Senior member

Senior member

  • Posts: 267
  • Joined: 13 Nov 2006, 04:07

Unread post30 Jul 2019, 18:28

sprstdlyscottsmn wrote:
steve2267 wrote:Hey QS, while this will vary with altitude and conditions, have your former colleagues driving Lightnings stated how fast the jet will true out at, at max Mil power setting?

More of a curiosity question than anything. And, of course, may be privileged info...

"In full war equipment operates F-35 effortlessly 10,000 to 15,000 feet higher than our F-16 can, without using afterburner. The speed in 'cruises' is without further 50 to 80 knots higher. " I think it was Dobly that said that. I only have it credited as "Norwegian test pilot"

Major Morten “Dolby” Hanche

https://nettsteder.regjeringen.no/kampf ... elt-annet/
Offline

sprstdlyscottsmn

Elite 4K

Elite 4K

  • Posts: 4406
  • Joined: 10 Mar 2006, 01:24
  • Location: Phoenix, Az, USA

Unread post30 Jul 2019, 18:38

Thought so, thanks for the confirmation.
"Spurts"

-Pilot
-Aerospace Engineer
-Army Medic
-FMS Systems Engineer
Offline

quicksilver

Elite 2K

Elite 2K

  • Posts: 2620
  • Joined: 16 Feb 2011, 01:30
  • Warnings: 1

Unread post30 Jul 2019, 20:14

steve2267 wrote:Hey QS, while this will vary with altitude and conditions, have your former colleagues driving Lightnings stated how fast the jet will true out at, at max Mil power setting?

More of a curiosity question than anything. And, of course, may be privileged info...


No. Details generally not public. I don’t ask; they don’t offer.
Offline

quicksilver

Elite 2K

Elite 2K

  • Posts: 2620
  • Joined: 16 Feb 2011, 01:30
  • Warnings: 1

Unread post30 Jul 2019, 21:15

LtCol Hank Griffiths, who commanded the test squadron at EDW some years back said this on the matter —

“What we can do in our airplane is get above the Mach with afterburner, and once you get it going ... you can definitely pull the throttle back quite a bit and still maintain supersonic, so technically you're pretty much at very, very min[imum] afterburner while you're cruising," Griffiths said. "So it really does have very good acceleration capabilities...”

DT test guy...not prone to spin or hyperbole. Just the facts.
Offline
User avatar

steve2267

Elite 2K

Elite 2K

  • Posts: 2153
  • Joined: 12 Jun 2016, 17:36

Unread post30 Jul 2019, 21:51

quicksilver wrote:LtCol Hank Griffiths, who commanded the test squadron at EDW some years back said this on the matter —

“What we can do in our airplane is get above the Mach with afterburner, and once you get it going ... you can definitely pull the throttle back quite a bit and still maintain supersonic, so technically you're pretty much at very, very min[imum] afterburner while you're cruising," Griffiths said. "So it really does have very good acceleration capabilities...”

DT test guy...not prone to spin or hyperbole. Just the facts.


Based on your knowledge and experience, wouldn't "very very min[imum] afterburner" still drink fuel at a rather prodigious rate? (Though far less than max burner.) I am guessing the motor is still burning a substantial amount of fuel more than max Mil. But what does this piston popper know?
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.
Offline

sprstdlyscottsmn

Elite 4K

Elite 4K

  • Posts: 4406
  • Joined: 10 Mar 2006, 01:24
  • Location: Phoenix, Az, USA

Unread post30 Jul 2019, 21:57

Of course. Using min burner to hold 1.2M vs Mil power to hold .99M is going to be in the ballpark of 2-3 times the fuel flow. Actual Drag may not be as high at 1.2M as would be expected relative to .99M. .99M is near maximum trans-sonic wave drag while 1.2M is usually well on the way back down to the steady supersonic condition. 300% fuel flow for 120% speed? no one is going to think that's a good plan. Even moreso that 0.99M is probably 150% fuel flow compared to 0.93-0.95. Max R and Max Mil can be very different fuel flows for a small change in speed.
"Spurts"

-Pilot
-Aerospace Engineer
-Army Medic
-FMS Systems Engineer
Offline

quicksilver

Elite 2K

Elite 2K

  • Posts: 2620
  • Joined: 16 Feb 2011, 01:30
  • Warnings: 1

Unread post30 Jul 2019, 23:47

steve2267 wrote:
quicksilver wrote:LtCol Hank Griffiths, who commanded the test squadron at EDW some years back said this on the matter —

“What we can do in our airplane is get above the Mach with afterburner, and once you get it going ... you can definitely pull the throttle back quite a bit and still maintain supersonic, so technically you're pretty much at very, very min[imum] afterburner while you're cruising," Griffiths said. "So it really does have very good acceleration capabilities...”

DT test guy...not prone to spin or hyperbole. Just the facts.


Based on your knowledge and experience, wouldn't "very very min[imum] afterburner" still drink fuel at a rather prodigious rate? (Though far less than max burner.) I am guessing the motor is still burning a substantial amount of fuel more than max Mil. But what does this piston popper know?


Jets burn prodigious amounts of JP in mil — F-22 included. Operationally, sometimes you just need the speed... :wink:
Offline

Corsair1963

Elite 5K

Elite 5K

  • Posts: 5626
  • Joined: 19 Dec 2005, 04:14

Unread post31 Jul 2019, 01:00

It will be interesting to see how the XA100 or XA101 would change the above debate??? :|
Offline

viper12

Senior member

Senior member

  • Posts: 262
  • Joined: 28 Jun 2017, 14:58

Unread post31 Jul 2019, 01:26

sprstdlyscottsmn wrote:Of course. Using min burner to hold 1.2M vs Mil power to hold .99M is going to be in the ballpark of 2-3 times the fuel flow.


Isn't that figure a bit high ? The Finnish specs sheet gave around 24.4K lb/h for mil power and some 81K lb/h in afterburner for the F-35A, so in the worst case scenario, minimum afterburner would be close to full afterburner, at 73.2 lb/h or so.
Everytime you don't tell the facts, you make Putin stronger.

Everytime you're hit by Dunning-Kruger, you make Putin stronger.
Offline
User avatar

spazsinbad

Elite 5K

Elite 5K

  • Posts: 23154
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post31 Jul 2019, 03:10

playloud wrote:
sprstdlyscottsmn wrote:
steve2267 wrote:Hey QS, while this will vary with altitude and conditions, have your former colleagues driving Lightnings stated how fast the jet will true out at, at max Mil power setting?

More of a curiosity question than anything. And, of course, may be privileged info...

"In full war equipment operates F-35 effortlessly 10,000 to 15,000 feet higher than our F-16 can, without using afterburner. The speed in 'cruises' is without further 50 to 80 knots higher. " I think it was Dobly that said that. I only have it credited as "Norwegian test pilot"

Major Morten “Dolby” Hanche

https://nettsteder.regjeringen.no/kampf ... elt-annet/

English Transration Reference here: viewtopic.php?f=55&t=27497&p=295008&hilit=Hanche+right+stuff#p295008

Earlier 'gabriele' posted the original link: viewtopic.php?f=22&t=27186&p=289639&hilit=Hanche+right+stuff#p289639
part from Google Transrate: "...In full war equipment operates F-35 effortlessly 10,000 to 15,000 feet higher than our F-16 can, without using afterburner. The speed in 'cruises' is without further 50 to 80 knots higher. In the F-16, I must use afterburner and take running speed before a missile shot. F-35 "cruiser" both faster and higher. Therefore, I am ready to shoot far anytime.

F-35 also has more fuel than we are accustomed to, it carries the load inside and is not as dependent on afterburner. Therefore we are left with more range than the F-16 and similar aircraft can achieve. "Combat radius" for the F-35 is between 30% and 70% longer than we get with the F-16! The extra range comes in handy in our elongated country. Range may alternatively be replaced in endurance over a given area...."
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
Previous

Return to General F-35 Forum

Who is online

Users browsing this forum: No registered users and 13 guests