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Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 30 Nov 2016, 19:01
by playloud
garrya wrote:F-15C at 40K feet need 90 seconds to go from Mach 0.8 to 1.2

F-35A at 30K feet need 64 seconds to go from Mach 0.8 to 1.2
But iam not sure how 10K feet different would really affect them

F-100-PW-100
I wonder how that compares to an Eagle with a modern engine?

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 30 Nov 2016, 19:38
by gta4
A F-15E with GE129 and without CFT is a beast in every aspect of energy maneuverability and I doubt how much advantage F-22 could have over it.

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 01 Dec 2016, 17:53
by sprstdlyscottsmn
I have those charts up right now. First of all, looking at the chart it take 68s to accelerate from 0.8-1.2M, not 90s.

F-15C with (4) AIM-7, (4) AIM-9, CL pylon, PW-220 engines, and at 48,000lb (~14% lighter than the Eagle sheet on the previous page) 40K 0.82-1.22 acceleration is 77s. Weight corrected to 42,000lb gives 67.4s. (Gives performance advantage relative to PW-200 engines on previous page)

F-15C clean, PW-220 engines, and at 40,000lb (~5% lighter than the Eagle sheet on the previous page) 40K 0.82-1.22 acceleration is 50s. Weight corrected to 42,000lb gives 52.5s. (Shows how much drag is caused by the air-to-air load)

F-15E with no CFT, PW-220 engines, and at 42,800lb (~2% heavier than the Eagle sheet on the previous page) 40k 0.84-1.24M acceleration is 60s. Weight corrected to 42,000lb gives 58.9s. (Shows the intrinsically higher drag of the F-15E canopy)

F-15E with no CFT, PW-229 engines, and at 43,600lb (~4% heavier than the Eagle sheet on the previous page) 40k 0.84-1.24M acceleration is 45s. Weight corrected to 42,000lb gives 43.3s. (Shows the performance advantage of the PW-229)

F-15E with CFT, (4)AIM-7, (4)AIM-9, PW-229 engines, and at 59,600lb (~42% heavier than the Eagle sheet on the previous page) 40k 0.84-1.24M acceleration is 92s. Weight corrected to 42,000lb gives 64.83s (Shows the higher drag of the weapons and CFT)

Weight correcting the accelerations allows a more direct comparison of excess thrust and can be done since the planes are the same. Comparing the F-15C -200 and -220 times and then the F-15E -220 and -229 times it stands to reason that the F-15C with (4) AIM-7, (4) AIM-9, CL pylon, and a PW-229 motor would have a .8-1.2M acceleration time of 49.5s at 42,000lb. So while the F-15C accelerates 12.2% faster than the F-15E when they are both clean and using PW-220 motors at the same weight, once they are both loaded up and using PW-229 motors the F-15C accelerates 31% faster. This shows the wave drag difference the CFTs have.

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 08 Jan 2017, 20:30
by gta4
The dag of the canopy of F-15E is higher than standard F-15C, but a clean (no CFT), pw229 powered F-15E could out-accelerate almost anything that flies.

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 09 Jan 2017, 11:24
by Corsair1963
gta4 wrote:A F-15E with GE129 and without CFT is a beast in every aspect of energy maneuverability and I doubt how much advantage F-22 could have over it.



Problem is the F-15E never fly's without CFT's or almost never.

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 09 Jan 2017, 11:26
by Corsair1963
gta4 wrote:The dag of the canopy of F-15E is higher than standard F-15C, but a clean (no CFT), pw229 powered F-15E could out-accelerate almost anything that flies.



Still the F-15C and/or F-15E would still carry external stores on any combat mission. Which, will greatly effect it's acceleration....sounds like the usual Apple and Oranges comparison with the F-35.

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 09 Feb 2017, 20:30
by gta4
No official description of "pedal turn" is given by LM.
I don't think pedal turn is the following maneuver because it is well beyond 90 deg/sec insdead of the 28 deg/sec:

The pedal turn should be a slower version of this maneuver, but with less energy and altitude loss to make that 28deg/sec constant.
Maybe Herbst?

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 09 Feb 2017, 20:40
by steve2267
gta4 wrote:The pedal turn should be a slower version of this maneuver, but with less energy and altitude loss to make that 28deg/sec constant.
Maybe Herbst?


That is what I have hypothesized / enquired about. So far no confirmation from anyone (that knows).

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 09 Feb 2017, 20:49
by spazsinbad
To get a YouTube video to show from the URL put the yibbidy-yibbidy part between the Utube brackets:

[youtube]5hERYdmjZWA[/youtube - last square bracket left out deliberately to show the method then added below....


Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 09 Feb 2017, 21:49
by juretrn
spazsinbad wrote:yt video snip


That video seems highly suspect, to me it sounds the pilot is saying the F-35 was out of control and was "stabilised" (I don't know the proper terminology) by the controls first in one axis, and then another.

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 10 Feb 2017, 01:13
by spazsinbad

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 03 Mar 2017, 22:54
by gta4
All critics from pilots focus on F-35's transonic performance (sustained G, acceleration), but so far no complain is about F-35's subsonic performance. However, F-35's subsonic performance are widely praised (constant turn rate, acceleration, roll rate, nose-pointing rate, controllability...). I don't see any adversary could get a favorable exchange ratio against a F-35 in close range fight.

All major aversaries are underperformed in certain aspects:

Su-27/30 (non-TVC version): does not have the subsobnic energy recovery like F-35 (20%+ gap); does not have any approach to counter F-35's pedal turn (28deg/sec sustained); does not have the high roll rate like F-35 (exceeding 300deg/sec).

Su-30 (with TVC): does not have the subsobnic energy recovery like F-35 (20%+ gap); may have approaches to counter F-35's pedal turn when TVC is engaged, but still could not acheive the nose-pointing rate in a controlled spin (F-35 could acheive 90+deg/sec in a controlled spin); does not have the high roll rate like F-35 (exceeding 300deg/sec).

Su-35 (with TVC): similar to the previous case, except that subsonic acceleration is closer to F-35.

T-50: similar to the Su-35 case, and bear in mind that T-50 is a prototype with insufficient avionics and structure strengh. T-50 may subject to weight increase and maneuverability reduction when in mass production.

J-31: the worst performer, needless to say.

J-20: similar to the Su-27/30 (non-TVC version) case.

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 04 Mar 2017, 09:19
by garrya
gta4 wrote:
All major aversaries are underperformed in certain aspects:

Su-27/30 (non-TVC version): does not have the subsobnic energy recovery like F-35 (20%+ gap); does not have any approach to counter F-35's pedal turn (28deg/sec sustained); does not have the high roll rate like F-35 (exceeding 300deg/sec).

Iam under the impression that Su-27 has the best STR of all 4th gen aircraft when fuel are equalized for similar mission profile , doesn't it ?
gta4 wrote:Su-30 (with TVC): does not have the subsobnic energy recovery like F-35 (20%+ gap); may have approaches to counter F-35's pedal turn when TVC is engaged, but still could not acheive the nose-pointing rate in a controlled spin (F-35 could acheive 90+deg/sec in a controlled spin); does not have the high roll rate like F-35 (exceeding 300deg/sec).

Can you elaborate in more detail? what is the nose pointing rate of Su-35 and what is the roll rate ?
gta4 wrote:J-31: the worst performer, needless to say.

isn't J-31 basically the same as F-35 ?. If the Chinese success with their new engine then J-31 will have better T/W than F-35. J-31 is also slightly flatter so it may has slightly less drag too.

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 04 Mar 2017, 10:48
by gta4
garrya wrote:Iam under the impression that Su-27 has the best STR of all 4th gen aircraft when fuel are equalized for similar mission profile , doesn't it ?

I do think we have discussed about this before:
viewtopic.php?f=55&t=52510&start=30
Since you did not rebuttal my uploaded proof, I assume you agreed with me.

What I have proved:

Su-27 at 18920kg flying weight could sustain at 21 deg/sec, and that is about 1800kg total fuel weight.

To achieve similar afterburner duration, a F-15C needs only 1600kg fuel, resulting in 15200kg total flying weight. The corresponding sustained rate of turn is 22.5 deg/sec (converted from 20.5 deg/sec at 37000lb. See flight manual).

To achieve similar afterburner duration, a F-18E needs only 1500kg fuel, resulting in 15792kg total flying weight. The corresponding sustained rate of turn is 21.5 deg/sec (converted from 18 deg/sec at 42100lb. See GAO report). Note that we are using single seater 18E, not 18F. 18F is slightly heavier (32000lb vs 31500lb operation empty weight).

To achieve similar afterburner duration, a F-16C-50 needs only 936kg fuel, resulting in 9675kg total flying weight. The corresponding sustained rate of turn is 22 deg/sec (converted from 21.5 deg/sec at 22000lb. See flight manual). Note that the operating empty weight of F-16C-50 is 19261lb instead of 20000lb, where the latter is an approximated value which could not be used to calculate performance.

Re: Proof: F-35 can out-accelerate Su-27/35 in subsonic regi

Unread postPosted: 04 Mar 2017, 11:04
by gta4
garrya wrote:isn't J-31 basically the same as F-35 ?. If the Chinese success with their new engine then J-31 will have better T/W than F-35. J-31 is also slightly flatter so it may has slightly less drag too.


J-31 is basically Mig-29 with internal weapon bays, and given the empty weight of Mig29, the empty weight of J-31 is unlikely to be inferior than 13000kg. Note that even Mig-29K weights 12700kg.

Hint: weapon bay + retractable mechanism = at least 1500 kg.

So J-31 needs an new engine of at least 9750kg thrust to achieve the same T/W as F-35, which is very unlikely because the new engine is an derivative of RD-33. Even the most powerful RD-33 derivative so far (the one that Mig-29K equips) delivers only 8700kg thrust in normal mode, and 9000kg thrust in special mode.

And, no aerodynamic proof has shown that flatness has anything to do with the drag, especially subsonic drag. For instance, no piston fighters are slimmer of flatter compared to modern jets, but they are more efficient in subsonic. However, the bigger wing sweep of J-31 gives it more induced drag. Note that F-35 has the smallest wing sweep among all 4th and 5th gen (except hornet). If you look carefully, all Chinese and Russian 5th gen prototypes employ bigger wing sweep than F-22 and F-35, that is a trade-off (subsonic vs supersonic) considering the fact that they need to use weaker engines to achieve supercruise.