dfwjim1
Topic Author
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Joined: Fri Sep 09, 2011 8:46 pm

Jet fighters and afterburners?

Mon May 06, 2019 12:12 am

I work near Hollywood/Fort Lauderdale International Airport and every time a fighter jet departs the airport it is in afterburner and makes a very steep climb out. There are no fighters on alert at FLL so fighters departing the airport are either there for airshows or passing through. Bottom line is it really necessary for fighter jets to use afterburners for take off in non combat/emergency situations?
 
DarkKnight5
Posts: 188
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Re: Jet fighters and afterburners?

Mon May 06, 2019 12:15 am

Yes.
 
RetiredWeasel
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Re: Jet fighters and afterburners?

Mon May 06, 2019 12:39 am

DarkKnight5 wrote:
Yes.

Not accurate. F-15s and F-16s make frequent non-AB takeoffs. It all depends on the aircraft's weight, runway length and environmental conditions. Don't know for sure about F-18s, but heard they always do AB takeoffs regardless. F-22,35??? The north RW at FLL is 9000 ft long which is long enough for fighters to do non-AB takeoffs. However it's up to the pilots to do decide. Rule of thumb, back in the my day, : if a non-AB takeoff didn't use over 50% of the runway to lift off, then it was optional if you really wanted to save gas.
 
Ozair
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Re: Jet fighters and afterburners?

Mon May 06, 2019 12:42 am

DarkKnight5 wrote:
Yes.

It is a little more flexible than that...

The use of burner is based on the take off weight and runway distance. Shorter runway and higher take off weight and burner will be used. Lower weight or longer runway and often the jets can take off fine with mil power. Of course if the pilot wants to show off then burner is the only option available...
 
Ozair
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Re: Jet fighters and afterburners?

Mon May 06, 2019 12:49 am

RetiredWeasel wrote:
Don't know for sure about F-18s, but heard they always do AB takeoffs regardless.

I have done both from a standard runway, weight was the determining factor.

RetiredWeasel wrote:
F-22,35???

Same as F-15/16.

The other big factor is noise. Several F-35 operators have extended their runways to allow mil power take offs with the intent to reduce the noise footprint so clearly it is possible. Hence the proximity of these runways to civilian populations also impacts afterburner use.
 
checksixx
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Re: Jet fighters and afterburners?

Mon May 06, 2019 1:00 am

Ozair wrote:
Several F-35 operators have extended their runways to allow mil power take offs with the intent to reduce the noise footprint so clearly it is possible.


Who/Where?
 
Ozair
Posts: 4077
Joined: Mon Jan 31, 2005 8:38 am

Re: Jet fighters and afterburners?

Mon May 06, 2019 2:09 am

checksixx wrote:
Ozair wrote:
Several F-35 operators have extended their runways to allow mil power take offs with the intent to reduce the noise footprint so clearly it is possible.


Who/Where?

RAAF
As part of the Environmental Impact Statement for the flying operations of F-35A, the runway at RAAF Base Williamtown will be extended which will allow the majority of F-35A take-offs to be conducted without the use of afterburners reducing noise impacts to surrounding communities.

http://www.defence.gov.au/AircraftNoise ... gation.asp

I thought the Danes were also looking to extend but instead they moved operations to a different part of the airfield, the runways are already at sufficient length for MIL power takeoff.

Interesting to note non afterburner take-offs are common for F-35s at Luke.

Something else about "ground ops". It's time to get in the air. We usually take off in "MIL Power" - full engine without afterburner. The machine accelerates smoothly and steadily in MIL.

https://nettsteder.regjeringen.no/kampf ... en-i-f-35/ (Google translated text)
 
GalaxyFlyer
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Re: Jet fighters and afterburners?

Mon May 06, 2019 3:21 am

Compared to a Stage 3 civil jet, an F-15 or F-16 in basic engine is pretty loud, so they might not be doing burner take-offs.

GF
 
DarkKnight5
Posts: 188
Joined: Fri Apr 15, 2016 3:36 pm

Re: Jet fighters and afterburners?

Mon May 06, 2019 12:17 pm

RetiredWeasel wrote:
DarkKnight5 wrote:
Yes.

Not accurate. F-15s and F-16s make frequent non-AB takeoffs. It all depends on the aircraft's weight, runway length and environmental conditions. Don't know for sure about F-18s, but heard they always do AB takeoffs regardless. F-22,35??? The north RW at FLL is 9000 ft long which is long enough for fighters to do non-AB takeoffs. However it's up to the pilots to do decide. Rule of thumb, back in the my day, : if a non-AB takeoff didn't use over 50% of the runway to lift off, then it was optional if you really wanted to save gas.

Oh I thought the original post was a rhetorical question, so I was answering rhetorically.
 
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Nomadd
Posts: 230
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Re: Jet fighters and afterburners?

Mon May 06, 2019 1:22 pm

Was it necessary for F-4s to glide down on a bunch of grunts in tents and kick in the afterburners what sounded like three feet over their heads at 4am in the 70s?
 
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Moose135
Posts: 3068
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Re: Jet fighters and afterburners?

Mon May 06, 2019 1:32 pm

Nomadd wrote:
Was it necessary for F-4s to glide down on a bunch of grunts in tents and kick in the afterburners what sounded like three feet over their heads at 4am in the 70s?

Of course it was...
KC-135 - Passing gas and taking names!
 
DALMD80
Posts: 199
Joined: Thu Apr 04, 2019 2:25 pm

Re: Jet fighters and afterburners?

Mon May 06, 2019 2:06 pm

Thought it was SOP to do burner takeoffs. Also SOP to do the 4am burners. :duck:
You can take the boy away from aviation, but you can't take aviation out of the boy.
 
DigitalSea
Posts: 119
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Re: Jet fighters and afterburners?

Mon May 06, 2019 9:01 pm

Would afterburners be necessary if they could take off from a treadmill?
 
Ozair
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Joined: Mon Jan 31, 2005 8:38 am

Re: Jet fighters and afterburners?

Mon May 06, 2019 9:52 pm

DigitalSea wrote:
Would afterburners be necessary if they could take off from a treadmill?

That is close to an airliners.net war crime... ;)
 
DarkKnight5
Posts: 188
Joined: Fri Apr 15, 2016 3:36 pm

Re: Jet fighters and afterburners?

Tue May 07, 2019 3:50 am

DigitalSea wrote:
Would afterburners be necessary if they could take off from a treadmill?

I prefer a large tower to be erected in the center of the field. Then you have a long chain attached to the aircraft. As you accelerate, you go around and around the tower until you reach climb out velocity and release the chain, off you go. No burner necessary, also doesn’t need a long runway. Win, win, WIN.
 
DarkKnight5
Posts: 188
Joined: Fri Apr 15, 2016 3:36 pm

Re: Jet fighters and afterburners?

Tue May 07, 2019 3:52 am

Nomadd wrote:
Was it necessary for F-4s to glide down on a bunch of grunts in tents and kick in the afterburners what sounded like three feet over their heads at 4am in the 70s?

That capability was in the F-4 functional requirements document.
 
DALMD80
Posts: 199
Joined: Thu Apr 04, 2019 2:25 pm

Re: Jet fighters and afterburners?

Tue May 07, 2019 1:15 pm

DigitalSea wrote:
Would afterburners be necessary if they could take off from a treadmill?

Quite a headwind you got there, eh? Also... large, fast treadmill.
You can take the boy away from aviation, but you can't take aviation out of the boy.
 
WKTaylor
Posts: 57
Joined: Mon Jul 25, 2016 9:36 pm

Re: Jet fighters and afterburners?

Fri Jun 07, 2019 4:15 pm

NOTE. Afterburner is an 'old fashioned' term for a single-stage [off-on-off], short-term, engine thrust augmentation.

New engines have multistage thrust augmentation... allowing a range of thrust increase for 'the most efficient use of fuel-flow'.

The F100-100 [Typical of F-15C/D models] has a 5 augmenter thrust-stages ... #1 thru #5.. selectable by the pilot... depending on take-off load VS runway available; and/or 'fighting power required'. Usually stage #1 or #2 are used for routine light-weight training flights... whereas #4 and #5 are used for very heavy-weight and/or scramble takeoffs.

Stage #1 is audibly noticeable but is visually unimpressive. However, stage #5 [typically very heavy take-off weights] treats the viewer to the full booming thunder and impressive 'beautiful' mach-diamonds.

When I was on an overseas base, I was 'given' multiple opportunities to witness night and/or AM/PM-twilight heavy-weight takeoffs with #5 stage augmenter thrust... of full squadrons of F-15s [TDY departures]... the aural fury and blue-white mach-diamonds of formation departures was well-worth the effort!

CAUTION. There is a price paid for using each stage of augmenter... increased fuel-flow and increased damage to the augmenter parts due to thermal shock/heat and sonic environment... as well increased stress on the core-engine.
 
GalaxyFlyer
Posts: 3400
Joined: Fri Jan 01, 2016 4:44 am

Re: Jet fighters and afterburners?

Fri Jun 07, 2019 5:08 pm

True, but only engineers use “thrust augmentation”. Lead: “Thrust Augmentation, Zone 2, NOW” won’t be heard.
Sorry for the F-14 wording.

GF
 
Reddevil556
Posts: 67
Joined: Thu Dec 27, 2018 2:09 pm

Re: Jet fighters and afterburners?

Sat Jun 08, 2019 1:59 am

It is a crime to take of in a fighter and not go full burner. What’s the point then? That is like buying a Mustang, but opting for the V6 option. I loved listening to the RAF Nados ripping out of KAF at night with afterburners glowing! The cannon on the Tornado was nice sounding too, but nothing beats the warthog’s musical masterpiece.
Jumped out of: C130H, C130J, C17A, C212, CH47, and UH60. Bucket list: C160, A400, C2
 
checksixx
Posts: 1219
Joined: Wed Mar 09, 2005 11:39 pm

Re: Jet fighters and afterburners?

Sat Jun 08, 2019 2:37 pm

WKTaylor wrote:
NOTE. Afterburner is an 'old fashioned' term for a single-stage [off-on-off], short-term, engine thrust augmentation.

New engines have multistage thrust augmentation... allowing a range of thrust increase for 'the most efficient use of fuel-flow'.

The F100-100 [Typical of F-15C/D models] has a 5 augmenter thrust-stages ... #1 thru #5.. selectable by the pilot... depending on take-off load VS runway available; and/or 'fighting power required'. Usually stage #1 or #2 are used for routine light-weight training flights... whereas #4 and #5 are used for very heavy-weight and/or scramble takeoffs.

Stage #1 is audibly noticeable but is visually unimpressive. However, stage #5 [typically very heavy take-off weights] treats the viewer to the full booming thunder and impressive 'beautiful' mach-diamonds.

When I was on an overseas base, I was 'given' multiple opportunities to witness night and/or AM/PM-twilight heavy-weight takeoffs with #5 stage augmenter thrust... of full squadrons of F-15s [TDY departures]... the aural fury and blue-white mach-diamonds of formation departures was well-worth the effort!

CAUTION. There is a price paid for using each stage of augmenter... increased fuel-flow and increased damage to the augmenter parts due to thermal shock/heat and sonic environment... as well increased stress on the core-engine.


They're most often referred to as 'shock diamonds', for good reason...FYI
 
RetiredWeasel
Posts: 706
Joined: Sat Jul 05, 2014 8:16 pm

Re: Jet fighters and afterburners?

Sat Jun 08, 2019 10:01 pm

checksixx wrote:
WKTaylor wrote:
NOTE. Afterburner is an 'old fashioned' term for a single-stage [off-on-off], short-term, engine thrust augmentation.

New engines have multistage thrust augmentation... allowing a range of thrust increase for 'the most efficient use of fuel-flow'.

The F100-100 [Typical of F-15C/D models] has a 5 augmenter thrust-stages ... #1 thru #5.. selectable by the pilot... depending on take-off load VS runway available; and/or 'fighting power required'. Usually stage #1 or #2 are used for routine light-weight training flights... whereas #4 and #5 are used for very heavy-weight and/or scramble takeoffs.

Stage #1 is audibly noticeable but is visually unimpressive. However, stage #5 [typically very heavy take-off weights] treats the viewer to the full booming thunder and impressive 'beautiful' mach-diamonds.

When I was on an overseas base, I was 'given' multiple opportunities to witness night and/or AM/PM-twilight heavy-weight takeoffs with #5 stage augmenter thrust... of full squadrons of F-15s [TDY departures]... the aural fury and blue-white mach-diamonds of formation departures was well-worth the effort!

CAUTION. There is a price paid for using each stage of augmenter... increased fuel-flow and increased damage to the augmenter parts due to thermal shock/heat and sonic environment... as well increased stress on the core-engine.


They're most often referred to as 'shock diamonds', for good reason...FYI


I don't know where WK Taylor is getting his info, but even most older fighters had variable thrust afterburners. Even the T-38 had a variable thrust range in AB. And in the older fighters and T-38 you always, if a single T/O, went full AB...not partial..during the T/O. The exception is when you would be doing a formation T/O. Then lead initially goes full A/B and after it lights, reduces the AB thrust a half or full throttle knob width. There is no "stage" indicator and don't think there is one in F-15s either. You just used throttle position to reduce it a little to give your wingman something to play with.
 
mmo
Posts: 1771
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Re: Jet fighters and afterburners?

Sun Jun 09, 2019 5:10 pm

WKTaylor wrote:
NOTE. Afterburner is an 'old fashioned' term for a single-stage [off-on-off], short-term, engine thrust augmentation.

New engines have multistage thrust augmentation... allowing a range of thrust increase for 'the most efficient use of fuel-flow'.




I'm not sure where you are getting your information but is not quite right. Afterburner is NOT an "old fashioned" term. It is correct and still used.

The use of afterburner and "the most efficient use of fuel flow" are oxymorons.

There are not stages of afterburner, they are called zones. And as retiredweasel correctly pointed out it is not an on or off. As soon as you move the throttles, thrust levers outboard and push you get min burner. Push full forward and you get full A/B.
If we weren't all crazy we'd all go insane!
 
Planeflyer
Posts: 1397
Joined: Fri Mar 14, 2014 3:49 am

Re: Jet fighters and afterburners?

Sun Jun 09, 2019 10:09 pm

is There a distinct signature to AB?

I live right over the flight path out of Miramar and have always wondered if the different type of sound generated by F18 on takeoff is related to thrust levels or environmental conditions.

Love the noise!
 
AirportOPS
Posts: 4
Joined: Sat Sep 26, 2015 8:45 pm

Re: Jet fighters and afterburners?

Mon Jul 01, 2019 6:48 pm

Keep in mind also that while FLL doesn't usually have fighters staged there, when the president is in Palm Beach FLL is used as staging for intercept fighters. Homestead ARB is also used but is around 50nm further south from FLL. There have been several intercepts of aircraft that have busted the VIP TFR in the last couple of years including one where there were many complaints of a sonic boom when the intercepting aircraft went supersonic catching up with the violating aircraft.

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