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

Unread postPosted: 21 Nov 2016, 03:05
by gta4
This is from the note of an aerospace engineer. I know there are other engineers in this forum so feel free to review it.

We have read from a TsAGI report that a Su-27 could accelerate from 600km/h to 1100km/h in 15 seconds, on 1000m, with 18920kg flying weight:

https://s14.postimg.org/nkknvh56p/Su_27 ... ration.jpg

The average acceleration is 9.25m/s2 from 600-1100km/h at 1000m.
We have also read from F-35 240-4.2 configuration report that F-35 could accelerate from 0.6-0.95 mach (696km/h-1102km/h) in 17.9 seconds, under Maneuver Weight at 15000 ft (4527 m):

download/file.php?id=18000&mode=view

The Maneuver Weight is defined as follows (60% internal fuel, about 5000kg):
https://s15.postimg.org/n9x5n6wyz/Tactical_MW.jpg

(The 540NM combat radius is almost the radius of full internal fuel with JDAMs loaded at take-off (but launched afterwards). I will prove that later in the appendix)

The question is: how to convert F-35’s performance at 4527m to 1000m under the same standard? Let’s do it.

Calculation standard: Both aircrafts carry the fuel allowance for the same afterburner time.
This standard is justified as follows: If we adopt some conventional standards, such as 50% internal fuel, this will be unfair for the aircraft with very high internal fuel or low fuel consumption. We can obtain that under 18920kg flying weight, Su-27 has only about 2000kg (4400lb) internal fuel, because a Su-27 with 5270kg fuel, 2xR-27 and 2xR-73 missiles, has a total weight of 23430 kg:
http://www.sukhoi.org/eng/planes/military/su27sk/lth/
So we need to know how much fuel is needed for F35 to have the same afterburner time as a Su-27 with 2000kg fuel. This leads to Prerequisite 1:

Prerequisite 1: It’s fair to let F-35 carry only 1560kg fuel, for allowance of the same afterburner time as a Su-27 with 2000kg fuel.

Explanation: The fuel consumption is proportional to engine thrust:
Fuel Consumption=SFC*Thrust*Time.
Modern fighter jet engines all have a SFC (specific fuel consumption) of about 1.9 (this approximation could be easily verified with published engine data), therefore, since the afterburner thrust of a F135 is 78% of that of two AL-31s, the fuel consumption of F135 is also 78% of that of two AL-31s. The result is 2000kg*78%=1560kg.
Compared to the Maneuver Weight (19000 kg) of F-35, this new fuel standard yeilds a total flying weight of 15600kg, which is a 18% reduction. (15600/19000=82%)
We are facing a new problem: How is engine thrust at 1000m compared to that at 4572m? This leads to Prerequisite 2:

Prerequisite 2: At a given airspeed (subsonic) and from medium to low altitude, engine thrust is proportional to air density.

Explanation: Theoretically, this is because the volumetric flow rate is almost constant at a given speed (at subsonic) and the air density is to be multiplexed with. This could be easily verified with published engine data. This is a very good approximation. You are welcome to use published data (i.e., RD-33 or AL-31 engine performance curves) to verify this Prerequisite.
So, at a given airspeed (for instance, 600km/h), the thrust at 1000m is 1.44 times as big as that at 4572m, because the ratio of air density is 1.44.
We know the comparison of thrust. What about the drag? This leads to Prerequisite 3:

Prerequisite 3: At a given airspeed (subsonic), the drag at 1000m is less than 1.44 times as big as that at 4527m.

Explanation: The drag is given by:
Drag=½*Drag Coefficient*air density*speed^2*wing area.
Let's compare 1000m and 4527m. The speed is fixed because it is given, and wing area remains unchanged. The air density gives a factor of 1.44. The drag coefficient is almost the same but slightly smaller, because the zero lift drag coefficient is identical, but the lift coefficient required to maintain level flight is smaller due to higher air density, which yields a smaller induced drag coefficient. This concludes the explanation.

Prerequisite 4: At subsonic acceleration, the speed-time curve is a convex function, or in other words, the faster you fly, the harder you accelerate.

Explanation: Theoretically, this is because the drag increases so rapidly as you accelerate. This could also be easily verified with published data of some aircrafts, such as:
http://forum.keypublishing.com/attachme ... 1389782706
http://forum.keypublishing.com/attachme ... 1419959707

Prerequisite 4 tells us that, If we have two aircrafts A and B, and aircraft B has the same or better average acceleration in a faster speed interval, then it’s safe to say B can out-accelerate A.

Thank you for your patience for reading through the theories. Now here comes the essential part: performance conversion from 4527m to 1000m.

Math notation:
We note a the acceleration, v the air speed, T the thrust, D the drag, m the total mass of aircraft. At a given altitude, the acceleration, the thrust and the drag are not constant, but functions of speed, which is equivalent to write a=a(v), T=T(v) and D=D(v). Their relationship is given by:
eq1.png

---equation 1
At 4527m and maneuver weight, F-35 at maneuver weight, accelerates from 0.6-0.95 mach (696km/h-1102km/h) in 17.9 seconds (by injecting equation 1 into it):
eq2.png

---equation 2
At 1000m, notations are changed: we note a1000(v) the acceleration, T1000(v) the thrust, D1000(v) the drag, and m1000 the mass. Prerequisite 1~3 yields:
eq3.png

---equation 3
The time required to accelerate from 696km/h-1102km/h at 1000m is given by (by injecting equation 2 and 3 into it):
eq4.png

---equation 4
Equation 4 tells us that the time required to accelerate is less than 10.19 s. The average acceleration in the interval [696-1102km/h] is more than 11.06m/s2. According to Prequisite 4, it is safe to conclude that F-35 can out-accelerate Su-27 in subsonic region, with a significant margin of more than 19.5%.
Sukhoi has been advertising Su-35’s acceleration for a while. Su-35 has about 8% increases over Su-27, which is still inferior to F-35.
We already know F-35 has some special turning technique which delivers an astonishing 28deg/sec sustained turn:
https://s15.postimg.org/awie5l6aj/35turn_rate.jpg

viewtopic.php?f=22&t=52503&p=356274&sid=b041569202d3b491efee6d62de1e0d1a#p356274
With this turning performance, and coupled with strong subsonic acceleration to recover energy, F-35 will become a potent dogfighter once CLAW is opened up and maneuver restrictions are removed.

Appendix:
Why the 540NM combat radius is almost the radius of full internal fuel with JDAMs loaded at take-off (but launched afterwards)?
F-35 with JSMs and 2 AMRAAMs loaded when taking off, JSMs released during the mission, has a combat radius of 610NM with internal fuel:
download/file.php?id=22482&mode=view
The JSM is very light and is less than 908 lbs:
http://www.dtic.mil/ndia/2014PSAR/albright.pdf
SO, with the much heavier 2000lbs JDAM loaded, the combat radius will drop significantly. 540NM is a reasonable figure.

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

Unread postPosted: 21 Nov 2016, 04:14
by garrya
Interesting thread , too bad i dont know enough about aerodynamic to contribute :mrgreen:

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

Unread postPosted: 21 Nov 2016, 13:21
by eloise
would you mind if i took this to Keypublishing?

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

Unread postPosted: 21 Nov 2016, 14:20
by sferrin
eloise wrote:would you mind if i took this to Keypublishing?


Probably get more useful answers by taking it to the playground at the local elementary school.

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

Unread postPosted: 21 Nov 2016, 14:30
by sprstdlyscottsmn
That was not a bad "first-order approximation". It also lines up with much of the anecdotal evidence of "recovers airspeed much better than an F-16", "like flying an F/A-18 with (a turbo)/(four engines)".

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

Unread postPosted: 21 Nov 2016, 17:01
by gta4
eloise wrote:would you mind if i took this to Keypublishing?


It seems the author doesn't mind. You can do it.

Don't forget the equations. They are in images.

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

Unread postPosted: 21 Nov 2016, 18:25
by garrya
gta4 wrote:Don't forget the equations. They are in images.

Who made all these ? he must be very knowledgeable

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

Unread postPosted: 21 Nov 2016, 22:18
by gta4
garrya wrote:
gta4 wrote:Don't forget the equations. They are in images.

Who made all these ? he must be very knowledgeable


A geek from GeorgTech

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

Unread postPosted: 21 Nov 2016, 22:47
by garrya
gta4 wrote:
A geek from GeorgTech

Can you tell him to do Rafale and Typhoon too ? lol

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

Unread postPosted: 22 Nov 2016, 00:16
by steve2267
gta4 wrote:Prerequisite 3: At a given airspeed (subsonic), the drag at 1000m is less than 1.44 times as big as that at 4527m.

Explanation: The drag is given by:
Drag=½*Drag Coefficient*air density*speed^2*wing area.
Let's compare 1000m and 4527m. The speed is fixed because it is given, and wing area remains unchanged. The air density gives a factor of 1.44. The drag coefficient is almost the same but slightly smaller, because the zero lift drag coefficient is identical, but the lift required to maintain level flight is smaller due to higher air density, which yields a smaller induced drag coefficient. This concludes the explanation.


My only critique is that unless the author has figured a way to warp the gravity field, the weight of the two aircraft will be (essentially) identical (neglecting the extremely minute differences from being slightly further from the center of mass of the earth), requiring the lift to be the same. Does that not mean the induced drag coefficient will be the same?

Nevertheless, I do not think this negates the overall analysis.

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

Unread postPosted: 22 Nov 2016, 00:17
by count_to_10
We are talking about wet thrust, right?
Shouldn't that mean that specific thrust won't be at all related to the dry specific thrusts reported?

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

Unread postPosted: 22 Nov 2016, 00:57
by garrya
steve2267 wrote:
My only critique is that unless the author has figured a way to warp the gravity field, the weight of the two aircraft will be (essentially) identical (neglecting the extremely minute differences from being slightly further from the center of mass of the earth), requiring the lift to be the same. Does that not mean the induced drag coefficient will be the same?

Nevertheless, I do not think this negates the overall analysis.

He means lift coefficients. Thinner air mean higher AoA to get adequate CL at the same speed, which mean higher Cd also.

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

Unread postPosted: 22 Nov 2016, 02:44
by gta4
steve2267 wrote:
gta4 wrote:Prerequisite 3: At a given airspeed (subsonic), the drag at 1000m is less than 1.44 times as big as that at 4527m.

Explanation: The drag is given by:
Drag=½*Drag Coefficient*air density*speed^2*wing area.
Let's compare 1000m and 4527m. The speed is fixed because it is given, and wing area remains unchanged. The air density gives a factor of 1.44. The drag coefficient is almost the same but slightly smaller, because the zero lift drag coefficient is identical, but the lift required to maintain level flight is smaller due to higher air density, which yields a smaller induced drag coefficient. This concludes the explanation.


My only critique is that unless the author has figured a way to warp the gravity field, the weight of the two aircraft will be (essentially) identical (neglecting the extremely minute differences from being slightly further from the center of mass of the earth), requiring the lift to be the same. Does that not mean the induced drag coefficient will be the same?

Nevertheless, I do not think this negates the overall analysis.

Sorry that was my typo. I should write "lift coefficient" instead. Even though the weight of aircraft remains the same, the air density has changed. So the required lift coefficient has changed. So the induced drag coefficient has changed.

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

Unread postPosted: 22 Nov 2016, 02:47
by gta4
count_to_10 wrote:We are talking about wet thrust, right?
Shouldn't that mean that specific thrust won't be at all related to the dry specific thrusts reported?


But SFC are still almost indentical.

For all fighter jet engines:

SFC for military power are all around 0.8.

SFC for afterburner are all around 1.9.

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

Unread postPosted: 22 Nov 2016, 06:05
by garrya
Can someone confirm this :
“A set of CFTs carries 50 percent more fuel than the centerline external fuel tank, but has only 12 percent of the drag.” The CFTs are designed for the full F-16 flight envelope – up to 9 g’s, maximum angle of attack and sideslip and maximum roll rate.

http://defense-update.com/products/c/F-16-CFT.htm

Centerline tank has drag index of 18 when fully loaded , centerline pylon has drag index of 7

Image

So drag of CFT is 12*( 18+7)/100 =3 even less drag than a single Aim-120

For visual illustration :
This
Image
is about 7 % more draggy than this
Image

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

Unread postPosted: 22 Nov 2016, 06:06
by garrya
what is F-15 CFT DI

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

Unread postPosted: 22 Nov 2016, 19:50
by gta4
It's a bit off-topic. You can open a new thread about this.

First of all, it's not fair to consider DI of CFTs, because aircrafts are supposed to remove CFTs before air combat missions.

CFTs do create less drag but they have their own weight, so turning, climbing and acceleration performances are dropped significantly.

You would be surprised how draggy the pylon/launcher combo under F-15 wings are. One pylon/launcher combo has a DI of almost 10. Two combos under two wings give a DI of 20, which is bigger than a giant 300 gallon tank, or is twice as draggy as a small central line tank (the one that Mig29 carries)

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

Unread postPosted: 22 Nov 2016, 20:15
by XanderCrews
sferrin wrote:
eloise wrote:would you mind if i took this to Keypublishing?


Probably get more useful answers by taking it to the playground at the local elementary school.


indeed, most elementary school kids are open minded

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

Unread postPosted: 22 Nov 2016, 21:24
by eloise
sferrin wrote:
Probably get more useful answers by taking it to the playground at the local elementary school.

Some keypub member like Andraxxuss is very good with aerodynamic

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

Unread postPosted: 22 Nov 2016, 21:29
by basher54321
garrya wrote:what is F-15 CFT DI



Been discussed before - very little drag increase - an F-16 with CFTs has the same drag index as without.

I think F-15s have a different drag index system but F-15E CFTs with pylons have a lot of drag (more than 2 drop tanks IIRC) - but the basic CFTs are less draggy.

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

Unread postPosted: 22 Nov 2016, 21:38
by basher54321
gta4 wrote:First of all, it's not fair to consider DI of CFTs, because aircrafts are supposed to remove CFTs before air combat missions.



Doubtful - especially with the F-16 - the extra fuel, less drag and lower profile is far more beneficial.
and the things are a nightmare to remove and put on again if you read the crew comments on here.

F-15Es would always fly with them (very rarely take them off for check flights according to pilots) - USAF F-15Cs got round the issue by mostly not using them at all.

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

Unread postPosted: 22 Nov 2016, 22:37
by gta4
During India MMRCA competition, India official made an notorious decision: they let F-16 go through flight tests with CFTs. This decision was complained by LM but indian didn't listen to it. The F-16 was ranking top during the initial maneuverability test, but with CFTs equipped, it dropped to the bottom. This caused F-16 to be knocked out.

From this we know LM does not recommend carrying CFTs to perform air dominance missions.

Also, during the korean F-X competition, F-15K went through the performance test without CFTs and achieved astonishing energy performance (exceeded the climbing threshold by 50%). From this we also know that Korean are not against the idea to strip CFTs before going air dominance.

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

Unread postPosted: 22 Nov 2016, 23:24
by steve2267
gta4 wrote:During India MMRCA competition, India official made an notorious decision: they let F-16 go through flight tests with CFTs. This decision was complained by LM but indian didn't listen to it. The F-16 was ranking top during the initial maneuverability test, but with CFTs equipped, it dropped to the bottom. This caused F-16 to be knocked out.

I don't have a clear picture of how the CFT-equipped F-16 and competing aircraft were configured for this maneuverability test(s).

For the maneuverability test, were the competing aircraft required to carry fuel tanks under their wings? Or were they flown clean? For the F-16 with the CFTs, was it able to fly without any additional underwing fuel tanks?

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

Unread postPosted: 22 Nov 2016, 23:38
by basher54321
gta4 wrote:During India MMRCA competition, India official made an notorious decision: they let F-16 go through flight tests with CFTs. This decision was complained by LM but indian didn't listen to it. The F-16 was ranking top during the initial maneuverability test, but with CFTs equipped, it dropped to the bottom. This caused F-16 to be knocked out.

From this we know LM does not recommend carrying CFTs to perform air dominance missions.

Also, during the korean F-X competition, F-15K went through the performance test without CFTs and achieved astonishing energy performance (exceeded the climbing threshold by 50%). From this we also know that Korean are not against the idea to strip CFTs before going air dominance.


The F-15E is a stellar performer without CFTs on those check flights - other airforces may use them without CFTs or may not I guess.

If that was the only deciding factor why the F-16 lost (don't think it was) then it might explain to some extent why the MMRCA was such a farce (How many Rafales did they end up with again?) if they haven't got a clue what they are doing.

Maybe LM should have offered the jets without CFTs :D

Of course LM would be stupid to offer the same jet again some years later wouldn't they?

“Under our current proposal, Lockheed Martin is offering India the exclusive opportunity to produce, operate and export F-16 Block 70 aircraft,” he said. “We also foresee significant Indian participation in the F-16 supply chain based on Indian industry’s capacity to offer best-value F-16 supply chain options.”

http://www.defensenews.com/articles/deb ... india-trip

If there is as you assume a recommendation from LM to not use CFTs I guess they left it out of the manuals (silly them!) - but regardless of all that I would expect to see CFTs used for most missions including A-A.
Shame Poland didn't do BAP with their F-16s so we could see for certain what they might turn up with - but there are plenty of photos with them in training A-A with CFTs.
Obviously if you go on an A-G mission you might have to do A-A anyway (oh no) - and this notion of degraded agility with full CFTs is no more ridiculous than that of a fully fuelled Su-27 at takeoff!

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

Unread postPosted: 23 Nov 2016, 00:39
by gta4
http://carnegieendowment.org/files/Deco ... cision.pdf

I believe the test was carried without drop tanks but with some AA missiles, because the threshold is "to sustain 16 deg/sec at 5000ft." India atmosphere is hotter which will cause some performance loss (but not huge), I don't think any jet could achieve this sustained rate of turn with drop tanks. However, some powerful jet such as typhoon, which should have easily exceeded this threshold (I believe tyohoon could sustain more than 18deg/sec a 5000ft), achieved only 16.2deg/sec, so I believe some A-A missiles are carried.

BTW, So glad to see a super hornet is 93% as good as a typhoon in terms of sustained turn :mrgreen:

— until then, among the world’s most
wickedly agile air combat platforms —
with conformal fuel tanks (CFTs). These
CFTs, which can be removed between
missions but not jettisoned in flight,
extended the F-16’s already impressive
reach, but at the cost of robbing it of its
renowned sprightliness.

With its CFTs, the F-16IN’s handling
and sustained turn rates — which otherwise
rank among the world’s best —
dropped to the bottom relative to the
other MMRCA competitors and thus
provided the final strike against its inclusion
in the shortlist. The fact that the
CFT-equipped F-16IN would be less manoeuvrable
compared to Pakistan’s F-16
Block 50/52s made the Super Viper’s exclusion
from the MMRCA shortlist virtually
a foregone conclusion.

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

Unread postPosted: 23 Nov 2016, 01:09
by basher54321
Not a bad article that - don't completely agree with some of writers thoughts but at least gives an idea of where the issues were:

- the IAF did put the aircraft through its paces. At the end of the day, however, it was found ‘noncompliant’ — a term indicating that the aircraft did not meet certain technical criteria in the IAF’s Air Staff Quality Requirements (ASQRs) — in five areas, some of which were of critical importance to the service: growth potential; carefree handling (and automatic sensing of external stores); sustained turn rate; engine change time; and assurance against obsolescence over a 15-year period.

The F-16IN Super Viper is already a mature aircraft and while it is likely to evolve further where its sensors and weapons are concerned — especially for foreign markets — it is unlikely to remain the premier dogfighter it was
when first introduced into the United States Air Force. Since the IAF was looking to acquire an aircraft that would remain competitive over the next 30 years, the F-16IN appeared like a poorer choice relative to the competition in both growth potential and assurance against obsolescence. Although the IAF’s judgment on both these counts can be debated by airpower specialists, even the most ardent supporters of the F-16IN would find it difficult to claim that this legendary airplane would remain the world’s most nimble closein combatant or its premier multirole combat aircraft in, say, 2030. The F-16IN’s failure to meet the IAF’s standard where engine change time was concerned was due largely to an idiosyncratic mishap during the field trials. It is certain that if the trials were to involve multiple stochastic demonstrations of engine change, the F-16IN would have easily made the mark. Unfortunately, second chances are sometimes not available, and the IAF, for its own reasons, chose not to accept Lockheed Martin’s subsequent evidence of being able to meet the engine change standards laid down in the ASQR.

---

Beyond these characteristics, the service also wanted a fighter that would be the newest of the new, something unmatched in the region, the latest of the available choices, and one with the greatest growth potential. The two American aircraft in the Indian MMRCA competition were deficient by some of these
yardsticks, when matched against the three ‘Eurocanards’: the Eurofighter, the Rafale, and the Gripen.



Agree on this (in perhaps a different context):

Obviously, this by itself did not make them inferior war-fighting machines. Far from it. Marginal differences in aerodynamic performance rarely affect combat outcomes and whenever such deficiencies exist, better sensors and weapons and advanced combat tactics can often serve to compensate.

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

Unread postPosted: 23 Nov 2016, 16:05
by eloise
According to pilot, F-15C acceleration at subsonic speed is even higher than F-35.That is why it can dogfight with Su-27 despite lower turn rate. F-15 with F-110GE-132 would be unbeatable in vertical fight

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

Unread postPosted: 23 Nov 2016, 16:41
by gta4
eloise wrote:According to pilot, F-15C acceleration at subsonic speed is even higher than F-35.That is why it can dogfight with Su-27 despite lower turn rate. F-15 with F-110GE-132 would be unbeatable in vertical fight

If you put on the "fuel for same AB duration" restriction, you will find F-15 is also better at turning, with a noticeable margin.

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

Unread postPosted: 23 Nov 2016, 17:19
by gta4
It seems that the author's theory checks out. Someone verified it with F-15E data:

http://forum.keypublishing.com/showthre ... ost2358007


"
I checked the author's theory with F-15E data:
at 10000ft, the air density is 3 times as big as that at 40000ft, so the acceleration should be at least 200% better if the theory is correct.

from M0.8-1.0, at 10000ft, a 44000lb F-15E spends 7s in total, which is 9.37m/s^2.
from M0.8-1.0, at 40000ft, a 44000lb F-15E spends 20s in total, which is 2.95m/s^2. (remember, the speed of sound is different at higher altitude)

It is 217% better. Very good match indeed. The theory checks out.

By the way, it is also safe to assume that F-15E could easily out-accelerate Su-35 using this theory.
"

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

Unread postPosted: 23 Nov 2016, 19:56
by garrya
gta4 wrote: If you put on the "fuel for same AB duration" restriction, you will find F-15 is also better at turning, with a noticeable margin.

That is unlikely IMHO
Su-27 has very big CLmax
Image
At Mach 0.5 its max AoA is 24 => CL is 1.85
At Mach 0.6 its max AoA is 23 => CL is 1.7
At Mach 0.7 its max AoA is 22 => CL is 1.58
At Mach 0.8 its max AoA is 20 => CL is 1.45

Image

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

Unread postPosted: 23 Nov 2016, 20:11
by gta4
First thing first, Su-27 has only a usable Clmax of about 1.6.
1.83 is when tailing edge flaps are deployed (for low speed level flight).

The highest Clmax is probably super hornet, which is near 2.0.

F-15 also has a max Cl of about 1.6 (I can prove that with NASA test reports) and F-15 has lower wing loading, so F-15 has better Cl/wing loading ratio, which gives it a better instantaneous turn rate than Su-27. Surprise? :mrgreen:

TsAGI underestimated F-15's Cl to be 1.08 (rather than 1.6), which significantly underestimated F-15's instantaneous turn.

And again, in your figure Su-27 sustains a 20.8deg/sec in 18920kg flying weight, which is with 2000kg fuel. F-15 could achieve similar AB duration with 1800kg fuel and that is 13600+1800+174=15574kg (34325lb) flying weight. According to F-15 flight manual, it could sustain 20.5 deg/sec with 37000lb flying weight, so if we convert it to 34325lb (normal load factor is inversely proportion to flying weight, making the conversion pretty easy), the sustained rate of turn is 22.1deg/sec

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

Unread postPosted: 23 Nov 2016, 20:38
by garrya
gta4 wrote:First thing first, Su-27 has only a usable Clmax of about 1.6.
1.83 is when tailing edge flaps are deployed (for low speed level flight)

I think Mach 0.5 is fast enough speed for dogfight TBH

gta4 wrote:F-15 also has a max Cl of about 1.6 (I can prove that with NASA test reports) and F-15 has lower wing loading, so F-15 has better Cl/wing loading ratio, which gives it a better instantaneous turn rate than Su-27. Surprise? :mrgreen:
TsAGI underestimated F-15's Cl to be 1.08 (rather than 1.6), which significantly underestimated F-15's instantaneous turn.

I dont think F-15 CL can reach 1.6 , it lacks most criteria for high CL value like LERX or LEF or Negative stability. CL of 1.6 looks like something belong to F-16 instead , and it only reach that vale below a certain G load

Image
Image

gta4 wrote:And again, in your figure Su-27 sustains a 20.8deg/sec in 18920kg flying weight, which is with 2000kg fuel

Their figure is taken when Su-27 is at 50% fuel IMHO
i concluded that from their ITR value
Lift = 1/2*V^2*reference wing area*air density *CL

Take for example when speed is mach 0.5 ( about 164 meters/sec) => CL is 1.85
air density at sea level is about 1.2kg/m3
Su-27 wing area is about 62m2
so total amount of lift is 1.85 * 1/2 * 1.2 * 164.8^2 * 62 = 1879085N
Su-27 empty weight is 16380 kg, max internal fuel is 9400 kg, Su-27 with 50% fuel will weight about 21080 kg
max G it can pull based on lift generated is 1879085/9.81/21080 =about 9G. That seem to fit with value in the graph

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

Unread postPosted: 23 Nov 2016, 20:52
by gta4
Sorry, man, you made two mistakes:

1) When calculating the centripetal force, you forgot to add the component of thrust of AL-31F. It is huge to multiply 25000kg with sin 24deg. You will find the Clmax=1.6 if you do this compensation.

2) The 18920kg flying weight is claimed to be the calculation standard in TsAGI report. (305*62=18920. Cl max=1.6)
3.jpg

For early Su-27s, 18920kg is with 50% fuel (50% * 5270kg, not 50% * 9400kg. Please check with Sukhoi website). But now Su-27 is much heavier. Even the lightest Su-27SK has an operating weigh of more than 17400kg. So if you want to maintain 18920kg flyin weight, you have to sacrifice some fuel.

3) For F-15 cl max: I will show you the proof afterwards.


4) This was the brochure distributed by Sukhoi at airshow to promote flankers. Note the performances are calculated under 19000kg weight.
4.jpg

5.jpg

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

Unread postPosted: 23 Nov 2016, 21:17
by gta4
Another mistake:
Your Cl curve is not for F-16, but for an experimental model for LWF development.
F-16 has a Cl of 1.7 at 25deg, M0.9.
(I will show you the proof later, maybe tonight when I get access to my laptop)

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

Unread postPosted: 24 Nov 2016, 01:58
by garrya
gta4 wrote:1) When calculating the centripetal force, you forgot to add the component of thrust of AL-31F. It is huge to multiply 25000kg with sin 24deg.

25000kg*sin24 = about 10.000 ( so that about 0.5G for a loaded Su-27). Moreover, shouldnt that be the case for all aircraft at high AoA ?

gta4 wrote:For early Su-27s, 18920kg is with 50% fuel (50% * 5270kg, not 50% * 9400kg. Please check with Sukhoi website). But now Su-27 is much heavier. Even the lightest Su-27SK has an operating weigh of more than 17400kg. So if you want to maintain 18920kg flyin weight, you have to sacrifice some fuel.

From sukhoi website
http://www.sukhoi.org/eng/planes/military/su27sk/lth/

Su-27SK carry 9400 kg fuel
gta4 wrote:3) For F-15 cl max: I will show you the proof afterwards.

Iam looking forward to that. Never expected F-15CLmax to get that high tbh

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

Unread postPosted: 24 Nov 2016, 05:12
by gta4
From sukhoi website
http://www.sukhoi.org/eng/planes/military/su27sk/lth/

Su-27SK carry 9400 kg fuel

Please read the webpage carefully: The take-off fuel is not 9400kg, but 5270kg. So the half fuel is not 9400/2=4700, but 5270/2=2635.

I think I have given enough evidence to show that TsAGI uses 18920-19000kg as flying weight standard to calculate performance. Doesn't this number remind you of something? Hmmmmm.....

18920=16000(back in the days when Su-27 was light)+2635(the "half fuel of 5270kg")+2 R73 missiles. A typical air combat weight calculation.

But now Su-27 is much heavier, even the lightest Su-27sk. If it continues using 18920kg as performance standard, fuel weight must be sacrificed.

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

Unread postPosted: 24 Nov 2016, 05:16
by gta4
Iam looking forward to that. Never expected F-15CLmax to get that high tbh


https://www.nasa.gov/centers/dryden/pdf ... H-1243.pdf

F-15 has a Clmax of 1.6.

I have a similar wind-tunnel test result from a MIT report. If you want I can dig it out, will take some time though.

This is because F-15 uses a thick, round, and twisted leading edge which acts somehow like a fixed-angle leading edge flap. Russian didn't expect that so they used their experience on Mig-25 to estimate F-15's aerodynamic performance. Some performances are significantly underestimated.

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

Unread postPosted: 24 Nov 2016, 05:54
by gta4
To Garrya:

For F-16 aerodynamic curves, please Google:
Correlation of F-16 Aerodynamics and Performance Predictions with Early Flight Test Results," AGARD CP-242, by TS Webb, DR Kent, JB Webb

You will find F-16 has very steep lift curve slop (around 0.08), steeper than Su-27 (0.066). Your Cl curve could not be F-16's :mrgreen: Anyway, it never claims to be F-16's.

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

Unread postPosted: 24 Nov 2016, 06:17
by garrya
gta4 wrote:https://www.nasa.gov/centers/dryden/pdf ... H-1243.pdf
F-15 has a Clmax of 1.6.
.

That interesting indeed , but that CL is at 40 degrees though ( while it is about 25 degrees for F-16 and 22.5 degrees for Su-27). Can F-15 even reach that AoA in high G turn ?
Image

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

Unread postPosted: 24 Nov 2016, 06:27
by garrya
gta4 wrote:Please read the webpage carefully: The take-off fuel is not 9400kg, but 5270kg. So the half fuel is not 9400/2=4700, but 5270/2=2635

Iam under the impression that 50% fuel load mean 50% of maximum fuel load . Does it not ?. So if maximum internal fuel load of su-27 is 9400 kg , shouldnt 50% of that is 4700 kg ?

gta4 wrote:But now Su-27 is much heavier, even the lightest Su-27sk. If it continues using 18920kg as performance standard, fuel weight must be sacrificed.

Fair point

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

Unread postPosted: 24 Nov 2016, 15:20
by gta4
garrya wrote:
gta4 wrote:Please read the webpage carefully: The take-off fuel is not 9400kg, but 5270kg. So the half fuel is not 9400/2=4700, but 5270/2=2635

Iam under the impression that 50% fuel load mean 50% of maximum fuel load . Does it not ?. So if maximum internal fuel load of su-27 is 9400 kg , shouldnt 50% of that is 4700 kg ?

gta4 wrote:But now Su-27 is much heavier, even the lightest Su-27sk. If it continues using 18920kg as performance standard, fuel weight must be sacrificed.

Fair point


Good question.

In fact, no one (including Sukhoi) has ever used 9400/2=4700 to calculate performance, because it will make Su-27 very underperformed.
Su-27 has two "internal fuel" standard. When Sukhoi calculate range or radius, it uses 9400kg. When it calculate T/W ratio, it uses 5270kg/2 (not 9400kg/2). The rest of the fuel (9400-5270=4130kg) is treated as undroppable fuel tank.

For the maximum AOA of F-15, I know F-15 could easily sustain at 35-37deg based on airshow HUD view, I do have read a high AOA test report that it could maintain control at 40deg AOA. In fact F-15 is the second best AOA performer (only inferior to superhornet) in 4th Gen.

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

Unread postPosted: 24 Nov 2016, 16:27
by garrya
gta4 wrote:For the maximum AOA of F-15, I know F-15 could easily sustain at 35-37deg based on airshow HUD view, I do have read a high AOA test report that it could maintain control at 40deg AOA. In fact F-15 is the second best AOA performer (only inferior to superhornet) in 4th Gen.

Iam still wondering why Su-27 cant maintain same AoA and thus higher CL ? For F-16 case obviously its vertical stabilizers is the one getting in the way. But what stop Su-27 from getting to 40 AoA in a turn ? if it can get to higher CL than F-15 at 26 degrees then surely that value would be higher at 40 degrees ?

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

Unread postPosted: 24 Nov 2016, 16:34
by garrya
Btw , this
Image
308 meters/second = about Mach 0.85 at sea level

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

Unread postPosted: 24 Nov 2016, 16:51
by gta4
garrya wrote:
gta4 wrote:For the maximum AOA of F-15, I know F-15 could easily sustain at 35-37deg based on airshow HUD view, I do have read a high AOA test report that it could maintain control at 40deg AOA. In fact F-15 is the second best AOA performer (only inferior to superhornet) in 4th Gen.

Iam still wondering why Su-27 cant maintain same AoA and thus higher CL ? For F-16 case obviously its vertical stabilizers is the one getting in the way. But what stop Su-27 from getting to 40 AoA in a turn ? if it can get to higher CL than F-15 at 26 degrees then surely that value would be higher at 40 degrees ?


This is because Su-27 will lose lift rapidly once it exceeds 24deg. Its lift drops much faster than eastern jets.

By the way, according to F-16 test report by GD (the literature I recommended), F-16 could easily achieve a Cl of 1.7 at 24deg AOA, Mach 0.9. At lower subsonic speed I believe it could achieve it earlier.

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

Unread postPosted: 24 Nov 2016, 16:53
by gta4
garrya wrote:Btw , this
Image
308 meters/second = about Mach 0.85 at sea level


Sorry, man, that is not speed, but Wing Loading!!!! :mrgreen: :mrgreen: :mrgreen:

G/S, look at the unit, it is kg/square meters :D

and that is 305 not 308.

the total weight=305*62=18910kg for Su-27

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

Unread postPosted: 24 Nov 2016, 17:21
by garrya
gta4 wrote:This is because Su-27 will lose lift rapidly once it exceeds 24deg. Its lift drops much faster than eastern jets.

Any particular reason ? vortex separated from wing ?

gta4 wrote:By the way, according to F-16 test report by GD (the literature I recommended), F-16 could easily achieve a Cl of 1.7 at 24deg AOA, Mach 0.9. At lower subsonic speed I believe it could achieve it earlier.

I cant seem to be able to locate the literature
Can you post the link instead ?

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

Unread postPosted: 24 Nov 2016, 17:28
by gta4
garrya wrote:
gta4 wrote:This is because Su-27 will lose lift rapidly once it exceeds 24deg. Its lift drops much faster than eastern jets.

Any particular reason ? vortex separated from wing ?

gta4 wrote:By the way, according to F-16 test report by GD (the literature I recommended), F-16 could easily achieve a Cl of 1.7 at 24deg AOA, Mach 0.9. At lower subsonic speed I believe it could achieve it earlier.

I cant seem to be able to locate the literature
Can you post the link instead ?


I will upload one tonight.

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

Unread postPosted: 24 Nov 2016, 17:42
by gta4
So, are we agreed on these things?

1) Su-27's performance was calculated based off 18920-19000kg flying weight
2) Now Su-27 is much heavier. Fuel weight mush be sacrificed to meet the 18920kg flying weight standard
3) F-15 has a maximum Cl of 1.6 and has a better Cl/wing loading ratio
4) With the fuel for same AB duration, F-15 has better instantaneous turn, sustained turn, climbing rate and acceleration.

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

Unread postPosted: 25 Nov 2016, 01:16
by gta4
F-16 test data, look at the Cl at M0.9, AOA 19deg, is actually higher than 1.3.
F16 test 242.jpg

At medium lift coefficient, F-16 has steeper lift curve slope than Su-27. The initial slope is almost 0.09, significantly higher than Su-27

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

Unread postPosted: 25 Nov 2016, 01:22
by gta4
Look at your previous data, this is definitely not a F-16, because the initial lift curve slope is as small as 0.07. F-16 is close to 0.09.
And, the caption of the figure does not mention it is a F-16, right?
not_F16.jpg

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

Unread postPosted: 27 Nov 2016, 19:46
by gta4
OK back to the main thread, the acceleration. Obviously the F-35 is not good at transonic acceleration like a F-16, but the majority of dogfight takes place at subsonic, so the acceleration at lower speed is more relevant. It determines how you regain energy after each maneuver and how frequently you can execute each maneuver, like a "cool down" time.

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

Unread postPosted: 27 Nov 2016, 23:23
by steve2267
gta4 wrote:Obviously the F-35 is not good at transonic acceleration like a F-16, but the majority of dogfight takes place at subsonic, so the acceleration at lower speed is more relevant. It determines how you regain energy after each maneuver and how frequently you can execute each maneuver, like a "cool down" time.


Stooopid question: WHY is it obvious "not good acceleration like a F-16?"

Obvious because your numbers say so? Where again, do you get your numbers? Flight test data? Wind tunnel data? CFD results? Speculative numbers drawn from first-order, empirical studies with inputs gleaned from non-F-35 test reports / other aircraft?

I am not trying to slam you, just trying to understand "obvious" and "not good at transonic acceleration."

I am having difficulty reconciling your statement(s) with quotes from LM / BAE / Military pilots who swoon over the power of the motor, and compare F-35 acceleration to a clean F-16 (Beesley) and an otherwise clean F-16 with one centerline tank (which Gums says doesn't affect the F-16 much). I have also read statements / quotes here on F-16.net from program personnel stating the transonic acceleration is quite good and it goes through the Mach very easily. Granted, this last statement / assertion does not include a comparison to the Viper.

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

Unread postPosted: 28 Nov 2016, 00:17
by garrya
F-16 acceleration chart directly from flight manual
Image

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

Unread postPosted: 28 Nov 2016, 00:49
by steve2267
garrya wrote:F-16 acceleration chart directly from flight manual


OK. Do you have the same page from the F-35 flight manual?

If not, from where are you getting numbers for the F-35 acceleration? (I've been following this thread... but don't recall any times for accel V1 to V2 at 30,000 ft. OR are we using the same first order analysis that was used in comparing the F-35 to the SU-35?) If so, I apologize and will have to sacrifice some more brain cells and go back and re-read.)

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

Unread postPosted: 28 Nov 2016, 00:59
by vanshilar
I think it has to do with the change to the F-35's KPP (Key Performance Parameter) on transonic acceleration. You can read more about it here:

http://elementsofpower.blogspot.com/201 ... sonic.html

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

Unread postPosted: 28 Nov 2016, 01:10
by garrya
steve2267 wrote:
OK. Do you have the same page from the F-35 flight manual?


I dont but i think OP and you would have heard about changed in F-35 KPP ( A version took 64 seconds to go from Mach 0.8 to 1.2 )

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

Unread postPosted: 28 Nov 2016, 01:16
by garrya
To make stuff more interesting , here is F-15A acceleration
ImageImageImage

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

Unread postPosted: 28 Nov 2016, 07:41
by optimist
I now know it was silly of me to open the thread again, come on guys, take it back to keypub. clean f-16s vs loaded f-35. :doh:

you have the flight manuals, put the pods EW ect on, along with tanks and similar weapon load. They show what you think transonic acceleration is.

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

Unread postPosted: 28 Nov 2016, 08:10
by garrya
optimist wrote:I now know it was silly of me to open the thread again, come on guys, take it back to keypub. clean f-16s vs loaded f-35. :doh:

you have the flight manuals, put the pods EW ect on, along with tanks and similar weapon load. They show what you think transonic acceleration is.

there are drag index value in the table optimist, or you can add individual values as you like
Image

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

Unread postPosted: 28 Nov 2016, 08:23
by Corsair1963
steve2267 wrote:
gta4 wrote:Obviously the F-35 is not good at transonic acceleration like a F-16, but the majority of dogfight takes place at subsonic, so the acceleration at lower speed is more relevant. It determines how you regain energy after each maneuver and how frequently you can execute each maneuver, like a "cool down" time.


Stooopid question: WHY is it obvious "not good acceleration like a F-16?"

Obvious because your numbers say so? Where again, do you get your numbers? Flight test data? Wind tunnel data? CFD results? Speculative numbers drawn from first-order, empirical studies with inputs gleaned from non-F-35 test reports / other aircraft?

I am not trying to slam you, just trying to understand "obvious" and "not good at transonic acceleration."

I am having difficulty reconciling your statement(s) with quotes from LM / BAE / Military pilots who swoon over the power of the motor, and compare F-35 acceleration to a clean F-16 (Beesley) and an otherwise clean F-16 with one centerline tank (which Gums says doesn't affect the F-16 much). I have also read statements / quotes here on F-16.net from program personnel stating the transonic acceleration is quite good and it goes through the Mach very easily. Granted, this last statement / assertion does not include a comparison to the Viper.


QUOTE: the F-35 very nearly matches the performance of its' larger, more powerful cousin, the F-22 Raptor, Beesley explained. The "subsonic acceleration is about as good as a clean Block 50 F-16 or a Raptor- which is about as good as you can get." Beesley said.

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

Unread postPosted: 28 Nov 2016, 08:29
by Corsair1963
QUOTE: When asked about my first flight in the F-35, I compared it to flying a Hornet (F/A-18), but with a turbo charged engine. I now can quote a USMC F/A-18 Weapons School Graduate after his first flight in the F-35: «It was like flying a Hornet with four engines!

https://theaviationist.com/2016/09/20/d ... snt-agree/

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

Unread postPosted: 28 Nov 2016, 09:24
by optimist
garrya wrote:
optimist wrote:I now know it was silly of me to open the thread again, come on guys, take it back to keypub. clean f-16s vs loaded f-35. :doh:

you have the flight manuals, put the pods EW ect on, along with tanks and similar weapon load. They show what you think transonic acceleration is.

there are drag index value in the table optimist, or you can add individual values as you like
Image

Thanks, but I'm not trying to put an argument together. I'm sure you agree that it's up to those that do

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

Unread postPosted: 28 Nov 2016, 18:09
by gta4
Ok I think I should distinguish two terms: subsonic acceleration and transonic acceleration.

F-35 is definitely a beast in subsonic and I do believe it could out-accelerate Su27/35 at subsonic. But transonic is a whole different story.

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

Unread postPosted: 28 Nov 2016, 19:11
by playloud
Corsair1963 wrote:QUOTE: When asked about my first flight in the F-35, I compared it to flying a Hornet (F/A-18), but with a turbo charged engine. I now can quote a USMC F/A-18 Weapons School Graduate after his first flight in the F-35: «It was like flying a Hornet with four engines!

https://theaviationist.com/2016/09/20/d ... snt-agree/

Think that will calm the "must have twin-engine" crowd? :-)

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

Unread postPosted: 29 Nov 2016, 04:00
by wrightwing
gta4 wrote:Ok I think I should distinguish two terms: subsonic acceleration and transonic acceleration.

F-35 is definitely a beast in subsonic and I do believe it could out-accelerate Su27/35 at subsonic. But transonic is a whole different story.

Transonic under what conditions? It would depend on the fuel state, and payload. 4 to 6 AAMs, and 50% fuel? Or 2 2000lb JDAMs, 2 AAMs, and 18,000lbs of fuel? Same goes for Flanker. If it has a large payload/high fuel state, it's not going to be nearly as nimble, as a lightly armed/50% fuel state aircraft. Not all F-35s will be configured for A2G. The transonic acceleration figures assume 2 JDAMs, etc....

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

Unread postPosted: 29 Nov 2016, 08:35
by Corsair1963
gta4 wrote:Ok I think I should distinguish two terms: subsonic acceleration and transonic acceleration.

F-35 is definitely a beast in subsonic and I do believe it could out-accelerate Su27/35 at subsonic. But transonic is a whole different story.


True but the F-35 has exceptional aerodynamic qualities. Which, I doubt the Flanker can match clean let alone with a combat load!

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

Unread postPosted: 29 Nov 2016, 08:44
by Corsair1963
Corsair1963 wrote:
gta4 wrote:Ok I think I should distinguish two terms: subsonic acceleration and transonic acceleration.

F-35 is definitely a beast in subsonic and I do believe it could out-accelerate Su27/35 at subsonic. But transonic is a whole different story.


True but the F-35 has exceptional aerodynamic qualities. Which, I doubt the Flanker can match clean let alone with a combat load!


Quote: Alan Norman Chief Test Pilot for F-35

Performance of the F-35 is Outstanding, In fact the benefits of the F-35 are so great in its Aerodynamic Performance, its "Eye Watering"!

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

Unread postPosted: 29 Nov 2016, 18:09
by gta4
But the problem is that the assumptions made in the OP thread no longer works in transonic region. We can not obtain a precised estimation.

Nevertheless, most WVR dogfights take place at subsonic region, where F-35 has the power and the turn rate to excel.

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

Unread postPosted: 29 Nov 2016, 18:25
by wrightwing
gta4 wrote:But the problem is that the assumptions made in the OP thread no longer works in transonic region. We can not obtain a precised estimation.

Nevertheless, most WVR dogfights take place at subsonic region, where F-35 has the power and the turn rate to excel.

The assumptions regarding transonic performance, include 5000lbs of weapons, and >50% fuel state vs a clean F-16.

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

Unread postPosted: 29 Nov 2016, 19:00
by gta4
wrightwing wrote:
gta4 wrote:But the problem is that the assumptions made in the OP thread no longer works in transonic region. We can not obtain a precised estimation.

Nevertheless, most WVR dogfights take place at subsonic region, where F-35 has the power and the turn rate to excel.

The assumptions regarding transonic performance, include 5000lbs of weapons, and >50% fuel state vs a clean F-16.


Well, that is definitely not fair

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

Unread postPosted: 29 Nov 2016, 19:08
by gta4
My understanding about pedal turn + acceleration:

The pedal turn is executed at low speed, which means it does not require high initial speed like other air combat maneuvers. So, after executing this maneuver, with strong subsonic acceleration, F-35 could easily regain the speed required for this maneuver, and execute the next one. The short energy recovery time is crucial, which means F-35 could apply constant pressure on its opponent and force it to bleed energy. As long as the opponent does not recover energy as fast as F-35 does, it will become a sitting duck sooner or later.

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

Unread postPosted: 30 Nov 2016, 01:55
by Dragon029
Considering that the F-16 / F-35 pilot states that it's a sustained 28 deg/s, there may not be any need to regain speed if you're in the space that you want to be.

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

Unread postPosted: 30 Nov 2016, 08:20
by garrya
F-15C at 40K feet need 90 seconds to go from Mach 0.8 to 1.2
Image
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

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

Unread postPosted: 30 Nov 2016, 13:58
by basher54321
garrya wrote:F-15C at 40K feet need 90 seconds to go from Mach 0.8 to 1.2
But iam not sure how 10K feet different would really affect them


Quite a bit apparently - an F-16 B50 at 32,000 lbs (DI=50) at 40,000 ft is given around 90 secs but at 30,000 ft it is under 50 seconds.

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

Unread postPosted: 30 Nov 2016, 13:59
by basher54321
gta4 wrote:Ok I think I should distinguish two terms: subsonic acceleration and transonic acceleration.



Quite a big difference between subsonic and transonic acceleration where the drag starts to make a big difference - often differences in subsonic acceleration are in seconds whereas transonic acceleration differences are often in tens of seconds.

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.

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

Unread postPosted: 04 Mar 2017, 11:13
by gta4
garry wrote:Can you elaborate in more detail? what is the nose pointing rate of Su-35 and what is the roll rate ?


The fastest nose pointing rate (under control, of course) of F-35 video shows at least 90deg/sec. The video is in previous replies, this thread.

The fastest roll rate of F-35 video shows at least 300 deg/sec. The video: https://www.youtube.com/watch?v=qceZALo ... be&t=1m15s

No video of Su-35 demonstrates similar performances.

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

Unread postPosted: 05 Mar 2017, 11:47
by munny
I finally saw the f-35 at Avalon airshow yesterday and gotta say I'm impressed. The pilots didn't perform a full aerobatics display but did a few highish AoA turns with AB and a few with mil thrust. It definitely did NOT look sluggish at all.

Couple things I noticed. The f-16, f-22 and f-35 all flew during the hot, dry part of the day which gave a good opportunity to compare certain aspects of how they fly. The f-16 accelerated pretty well when it went nose down and full AB. The f-22 seemed a little more sluggish when it did the same. The f-35 pilot put his gear down a few times pretending he was going to land only to put them up again as he got to the start of the runway then planted the AB again. the f-35s acceleration in level flight looked on par to the f-16 in a 20 degree dive and looked a lot better than the raptor's. All at sea levelish of course.

Also I noticed during some of the high aoa turns the f-35s elevators were periodically flapping back to level during the turns. Claws kicking in I presume. Wonder what it can do when they open them up because the turns looked pretty impressive for something that "can't turn". The mil thrust, sustained turns looked good too. Nozzles close significantly at mil thrust which I would guess is great for frontal IR stealth when approaching a target or rear RCS when flying away.

Another vertical climb out (like the Norwegian demo) accelerating as it climbed at the start after a very short take off.

The second pilot commentating said that the f-35 really earns its money performance wise during sub to supersonic transition saying pretty clearly that it does it faster and more efficiently than other jets with stores loaded. Goes against certain reports on transonic acceleration.

The F-35 is significantly louder than the f-16, superhornet, and hornet. Much Lower pitched rumbling (thunder) sound than the others but with a much louder crackling sound than the others that makes everyone without ear protection cover up as it flies over.

The wing vortices trailing the jet snake around and create knots and patterns about 200m or so behind the jet. Pretty cool to watch.

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

Unread postPosted: 05 Mar 2017, 14:55
by mixelflick
munny wrote:I finally saw the f-35 at Avalon airshow yesterday and gotta say I'm impressed. The pilots didn't perform a full aerobatics display but did a few highish AoA turns with AB and a few with mil thrust. It definitely did NOT look sluggish at all.

Couple things I noticed. The f-16, f-22 and f-35 all flew during the hot, dry part of the day which gave a good opportunity to compare certain aspects of how they fly. The f-16 accelerated pretty well when it went nose down and full AB. The f-22 seemed a little more sluggish when it did the same. The f-35 pilot put his gear down a few times pretending he was going to land only to put them up again as he got to the start of the runway then planted the AB again. the f-35s acceleration in level flight looked on par to the f-16 in a 20 degree dive and looked a lot better than the raptor's. All at sea levelish of course.

Also I noticed during some of the high aoa turns the f-35s elevators were periodically flapping back to level during the turns. Claws kicking in I presume. Wonder what it can do when they open them up because the turns looked pretty impressive for something that "can't turn". The mil thrust, sustained turns looked good too. Nozzles close significantly at mil thrust which I would guess is great for frontal IR stealth when approaching a target or rear RCS when flying away.

Another vertical climb out (like the Norwegian demo) accelerating as it climbed at the start after a very short take off.

The second pilot commentating said that the f-35 really earns its money performance wise during sub to supersonic transition saying pretty clearly that it does it faster and more efficiently than other jets with stores loaded. Goes against certain reports on transonic acceleration.

The F-35 is significantly louder than the f-16, superhornet, and hornet. Much Lower pitched rumbling (thunder) sound than the others but with a much louder crackling sound than the others that makes everyone without ear protection cover up as it flies over.

The wing vortices trailing the jet snake around and create knots and patterns about 200m or so behind the jet. Pretty cool to watch.


Wouldn't wing vortices be a negative in air to air engagements? Meaning if you're flying Mig's, Flankers, J-31's etc you'd be easily able to differentiate the F-35 as hostile, in comparison to one of your own jets??

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

Unread postPosted: 07 Mar 2017, 02:28
by steve2267
mixelflick wrote:Wouldn't wing vortices be a negative in air to air engagements? Meaning if you're flying Mig's, Flankers, J-31's etc you'd be easily able to differentiate the F-35 as hostile, in comparison to one of your own jets??


IMO, the wingtip vortices produced by the the F-35 are a non-issue. ALL aircraft wings shed vortices off the wing tips. Given the design constraints of the F-35, I'm not sure you could easily re-design the wings to NOT give off such concentrated vortices.

But I really don't think it is an issue.

If an enema fighter is close enough to see wingtip vortices, he's in all likelihood already dead.

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

Unread postPosted: 22 Sep 2020, 22:19
by pron
Don't they have simulators in Russia? :doh:

The Western Military District announced that a Russian Su-30 (presumably Su-30SM) fighter crashed in Tver today. Both crewmembers ejected safely.

The военный осведомитель channel is saying that the Su-30SM that crashed today was actually shot down by a Su-35S fighter that accidentally shot the fighter with its cannon.
https://mobile.twitter.com/RALee85/stat ... 0200178689

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

Unread postPosted: 23 Sep 2020, 08:24
by Corsair1963
pron wrote:Don't they have simulators in Russia? :doh:

The Western Military District announced that a Russian Su-30 (presumably Su-30SM) fighter crashed in Tver today. Both crewmembers ejected safely.

The военный осведомитель channel is saying that the Su-30SM that crashed today was actually shot down by a Su-35S fighter that accidentally shot the fighter with its cannon.
https://mobile.twitter.com/RALee85/stat ... 0200178689


Reports say the Su-35 shot down the Su-30SM. Seems the cannon was loaded and the pilot was unaware. So, when he closed for the gun kill. It actually fired! :shock:

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

Unread postPosted: 23 Sep 2020, 09:37
by element1loop
So only a live-fire 'mode' then?

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

Unread postPosted: 23 Sep 2020, 15:03
by hornetfinn
Now that's some realistic training right there... :shock: Glad that nobody was seriously injured or dead in that incident.

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

Unread postPosted: 25 Sep 2020, 16:08
by ricnunes
LoL :shock:

I'm guessing that those Russians Sukhois don't have anything like this: :roll:
Image

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

Unread postPosted: 26 Sep 2020, 12:49
by mixelflick
Red Flag: Now the world's 2nd most realistic combat training...

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

Unread postPosted: 01 Oct 2020, 23:51
by nutshell
I can't understand the need to pull the trigger.

Couldn't he just called for a guns!guns!guns' ?

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

Unread postPosted: 02 Oct 2020, 08:20
by hornetfinn
nutshell wrote:I can't understand the need to pull the trigger.

Couldn't he just called for a guns!guns!guns' ?


I think the Air Combat Maneuver Instrumentation (ACMI) system will record the weapon events exactly when the trigger is pulled. So it can record and analyze the exact situation and flight state of shooter and target. That will give highly accurate estimate what would've happened in real life. Just calling "guns, guns, guns" would be vastly less accurate and more subjective. That's important in making sure that the pilots learn to use their weapons correctly in the heat of hard maneuvering.

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

Unread postPosted: 02 Oct 2020, 14:59
by milosh
For exercises, ground crew cut electricity to gun as safety measure but it look like someone forgot to do that.

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

Unread postPosted: 02 Oct 2020, 15:58
by sprstdlyscottsmn
not the first time either, this happened some years back with a MiG-29 as I recall.

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

Unread postPosted: 02 Oct 2020, 22:39
by ricnunes
milosh wrote:For exercises, ground crew cut electricity to gun as safety measure but it look like someone forgot to do that.


So, it's confirmed that there's no simulate/simulation mode/switch in Russian fighter aircraft? :doh:

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

Unread postPosted: 03 Oct 2020, 17:31
by milosh
ricnunes wrote:
milosh wrote:For exercises, ground crew cut electricity to gun as safety measure but it look like someone forgot to do that.


So, it's confirmed that there's no simulate/simulation mode/switch in Russian fighter aircraft? :doh:


Yes. It is simple to be done but they didn't want it because in case of real combat they want trigger is 100% working. Well known thing from cold war.

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

Unread postPosted: 04 Oct 2020, 09:38
by dragracingmaniac
Apparently the Rooskis don't simulate anything. :shock:

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

Unread postPosted: 04 Oct 2020, 19:47
by ricnunes
dragracingmaniac wrote:Apparently the Rooskis don't simulate anything. :shock:


Yeah, simulating is for pussies :roll:

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

Unread postPosted: 04 Oct 2020, 20:02
by madrat
It sounds unlikely the gun can fire with a simple trigger pull.

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

Unread postPosted: 04 Oct 2020, 21:41
by ricnunes
madrat wrote:It sounds unlikely the gun can fire with a simple trigger pull.


Apparently not with Russian fighter aircraft...