Andraxxus[ATTACH=CONFIG]238885[/ATTACH]
Then we have the dry thrust envelope and the high altitude maneuvering.
And this proves what? Surely I can use paint to draw that too, and would be more credible than APAA.
5G = 5 times lift of aircraft weight.
Lift = 1/2 * air density(at 60k) * Wing Area * Lift Coefficent * airspeed^2
Empty weight of F-22A = 19700kg
5*19700*9,8184 = 1/2 * 0,08891 * 78,04m2 * Lift Coefficent * 294,9^2
Lift Coefficent required for EMPTY F-22 to PULL (not sustain) 5Gs = 3,2
Such lift coefficient is nonexistent. Even half of it (1,6) is nonexistent for M0,9. Highest nominal Clmax EVER achieved is 2,1 for lowspeed flight. Theoratical maximum for single element airfoil is 3,06, no such thing ever built.
So clearly, F-22 cannot even pull 5Gs; even at its empty weight at M0,9. There are a dozen stupidities I would show but I won’t even bother dismissing that laughable chart further.
There is also the infamous video of the F15 pilot talking about how the F15C is slightly inferior to the Su30MKI in kinematics and way behind the F22 (I just assume that is most noticeable at higher altitude where thrust vectoring really does its job well).
Infamous because he was talking crap. 28deg/s claim is also impossible for similar reason as stated above.
I agree with every point in that list, but it isnt congruent with the reports ive read about the F22 meeting the F15 and the envelope charts Ive seen.
Similarily, I expected the F35 to perform better than it did in the David Axe report.
That’s what I am thinking too. Something isn’t right with all these reports; either F-35 is not as bad as people claim, or F-22 is not as good. And quite possibly, both.
At altitude wings and control surfaces lose their impact on controling the aircraft. The most efficient way to get the plane or object to turn is to point the thrust in a different direction.
Not everything changes, but while wings and control surfaces are doing their job in dense air they do lose that in thinner air. And at high altitude only the aircraft with thrust vectoring will maneuver well.
True, and such condition is defined as phi max state, where aircraft has the ability to turn (both aerodynamically and structurally), but has insufficient leverage to pull its nose up; That USUALLY occurs at high altitude on SOME aircraft, but its effects are low and limited to instantenious turns only. For example F-15 and Su-27 isn’t affected at all throughout the envelope (big is good in this case), MiG-29 is affected even from sea level (mechanical controls = bad), and F-16 only high supersonic above 35k feet (neg. stability = good, but small wing area = bad)
However it has no effect on dogfighting ability at all (too lazy to post a new attachment, so re-using this one):
[ATTACH=CONFIG]238892[/ATTACH]
As you can see on the righthand graph; even most heavily affected MiG-29 is already at degraded performance when max stick deflection becomes an issue; a MiG-29 pilot will stay below M0,85 to use its admirable aerodynamics anyway. In other words, putting TVC to MiG-29 would not improve its manerverability in dogfight; (though it would affect high supersonic BVR maneuverability, pulling higher instantenious Gs are good for disengaging, evading etc)
I would also claim BS on that. However, my claims are about the F22 at mostly high altitudes. So far, despite math saying the opposite, it does look like the F22 does perform better than the others at high altitude. I may be wrong though, but so far i have to go with the actual results that are presented to me instead of a strict number by number guessing game.
Of course, and since we both haven’t seen conclusive data (like flight manual or leaked manufacturer data etc), we are both chosing to believe what we think right.
Thrust vectoring doesnt lose effectiveness at the same rate as other control surfaces.
I just believe (because of TVC) that the turning capabilities of F22 deteriorates slower with altitude than for other fighters.
You do not understand; TVC will not be in effect at minimal AOA like sustained turns, with negative stability, elevator has no negative but also positive affects. With tremendous forces involved, TVC has no use at all;
At max deflection even F-22’s engines can only generate only 80,7 kN vertical force. At reasonable altitude of 5000 meters, and relatively slow at M0,9, a 6 m2 elevator area just rotated 4 degrees for 0,4 CL increase will generate 82 kN of lift force.
Which is more beneficial? Using elevators for negligable drag increase? or using TVC and losing 4% of your net thrust for no gain in the process?
And in real life, airframe design is important too; for example, Su-27S design is negative stable subsonic (which improves maneuverability), which requires less than 2 degrees of elevator deflection to fly subsonically. At high altitude transonic speeds, its positive stable to increase controllability. If armed with missiles, its also negative stable when supersonic, but not when its clean. Such configuration would not benefit anything from TVC other than departure safety, because aircraft literally switches between maneuvering efficiency and ease of controllability when desired or required. Gotta love the Sukhoi engineers.
Im no F22 lover,
I wasn’t referring to you 😀
AndraxxusI think your claim is just over simplified.
Every simplification favors F-16 and F-15 most and F-35 the least, which was kinda my point actually.
For instance, the flight envelope of the F22 is greater than for the F15.
Baseless claim; About F-22’s service ceiling, USAF says 50000+feet; LM says 60000 feet (no plus beside it). F-15E can also operate up to 63k feet.
F-22’s top speed is said to be mach-2 class, F-15E can operate up to M2,35 on STD DAY.
There is no single indication F-22’s flight envelope is greater than F-15.
The maneuverability at altitude (thanks to thrust vectoring among other things) is much greater for the F22.
As I’ve stated I was assuming inlet performance and drag coefficent IS same. This is no simplification but scientific method. Of course, in real life they are not same, so lets go into details;
To make F-22’s T/D equal with F-15E, either Cd curve or dynamic thrust must be improved by 15%. That is where all “simplifications” come in, so lets count them all;
Thrust:
1- a fixed inlet can never exceed a variable inlet. It may -at best- closely match it for a very limited part of the envelope.
2- Boilerplate exhausts have far greater losses, compared to round exhaust.
3- F-100 has lower bypass ratio than F-119, so higher % of thrust retained at high altitude.
Drag:
4-F-22 is newer design, so advancements like CFD should improve Cd0
5-F-22 has VLO considerations whereas F-15E is solely designed to be aerodynamic.
6-F-22 is negative stable F-15E is not.
7-Thrust vectoring may assist in trim, but may also have little or no effect at all.
8-F-22 has LE flaps so drag while maneuvering would decrease, and lift at hard turns increase.
That is 4 vs 4, with most important ones being 1,2,6,8 its 2 vs 2. So speaking of features doesn’t look very bright for F-22 is it?
All in all, at high altitude (where the F22 is designed to be) it is probably the finest aircraft in the world.
Finest? Possibly. Most maneuverable? Not in my eyes. At least, I don’t think there is enough scientific evidence that tells its even on par with F-15E.
At low altitude I could imagine that even a clean Gripen C would turn tighter.
You are assuming everything changes at high altitude? With inceasing altitude and decreasing air pressure, all aircraft will see degredation in maneuverability. And again, ALL aircraft will turn better without wavedrag holding them back, so best maneuverability will be made below M0,9, even for MiG-31.
Speaking of videos, F-22 sustains some 18deg/s at airshows. Immediately claimed that F-22 flies under G limitations in airshows. Its real funny to talk about G limits for an aircraft that flies for 25 years and in active service for 10 years but OK, lets swallow it and compare; an F-15C with half fuel needs puny 5Gs to sustain same 18deg/s. IF F-22 is better than F-15C, how strict can it be limited so it performs same? 4Gs? 3? I dare say, Something must be REAL wrong if you limit your 9G capable aircraft to just 3-4Gs. Even unmaintained, old, 7,33G capable F-14 had ended their career at 5,5G limit. In any case, F-22’s instantenious turns in videos show the problem is not pulling Gs, its sustaining them.
Then people claim a miracle happens when both aircraft climb to 20k feet, and F-22 suddenly becomes a monster that defeats anything else. No, I don’t buy it. The thing is, all these features like negative stability or LE flaps etc are ALREADY making difference at S/L too. Other then air density, NOTHING changes between M0,85 S/L and M0,85 30k feet.
Some F-22 lovers may call me biased, but I am merely asking WHY? If F-22 had so low wing loading that it would hold it back at low altitude, but give an edge at high altitude, or it had so tremendous T/W that it overcame the drag came with higher AOA needed for high alt maneuvering, I would accept. But TVC trimming? No, not a sufficent answer.
By the way, Speaking of videos, my calculation gives 87,7% T/D, and 87,8 T/W ratio between F-15 and F-22. I agree I am oversimplying and I DO expect some 5-10 improvement to drag figure, but do you really think that the ratio between F-22’s max observed sustained turn rate (18 deg/s) and F-15C’s stated STR (20,5 deg/s) is also 87,8% just because its a silly coincidence???? Or science is more important than looks and propoganda?
Andraxxushere
what is the fuel load?
Assuming 50%
what is F-16, F-18, F-15, F-4, F-5 max sustain G in similar conditions?
@M0,8 15000 feet
F-16C @22000lbs = 6,5G with 27% fuel
F-16C @24000lbs = 5,9G with ~50% fuel
F-16C @28000lbs = 5,1G with ~100% fuel
F-5E @13600lbs = 4,5G@ 15k feet with ~100% fuel
F-4E @40925lbs = 4,3G@ 15k feet with ~90% fuel
F-15C @35000lbs = @10k feet = 7,6G, @20k feet = 5,1G. On average: 6,4G @ 15k feet with ~50% fuel
F-15C @42000lbs = @10k feet = 6,2G, @20k feet = 4,4G. On average: 5,2G @ 15k feet with ~88% fuel + empty CFTs.
Now IF the F-35A can sustain 5,3Gs at 15k feet with 100% fuel, that is VERY VERY GOOD. If its with 50% fuel, that is still clearly better than F-16C or F-15C. Remember, F-35 carries 31% more internal fuel than F-15C. At ~50% fuel it can possibly match the range of F-15C with full internal fuel.
An interesting figure:
MiG-29G 6,6G @16,4k feet with 63% fuel.
@30k feet M0,9;
30 degree sustained bank turn means 1,155G or 1,07deg/s
45 degree sustained bank turn means 1,415G or 1,86deg/s
F-16, drag index = 200, MIL thrust @40000lbs =1,01G or 0,26 deg/s.
AndraxxusIt will be very interesting to see how the F-35 responds to an additional 20% of thrust. I think any complaints about the F-35’s ability to maintain its energy will prove short lived…
I believe any -alleged- complaints about F-35 is due to G, airspeed or AOA limitation; If you limit a clean F-16 to 6Gs, its maximum sustained rates (at least at low altitude) will be not better than F-4E;
Affects of such limits is often overlooked when talking about sustained turns; both lift and drag increase with V^2; but to achieve same lift (G), going faster is always more efficient, because lift coefficient stays more or less the same before stall, but reduced AOA reduces drag coefficient logarithmically. And with turn rates dependent on V not V^2, sustained turn rates generally increase linearly with increased speed until transonic range (M0,85).
“What an embarrassment, and there will be obvious tactical implications. Having a maximum sustained turn performance of less than 5g is the equivalent of an [McDonnell Douglas] F-4 or an [Northrop] F-5,” another highly experienced fighter pilot says. “[It’s] certainly not anywhere near the performance of most fourth and fifth-generation aircraft.”
Without even giving an altitude its all BS propoganda; a clean F-16, lightweight at 26000lbs, cannot even sustain 3.5Gs at 30k feet.
At BVR ranges, the F-35 may not be at a disadvantage against it.
Irrelevant advertised dream technology, I think F-35 will be at disadvantage againist F-22, T-50 or -if they manage to make it work- J-20. Just like an F-16 or MiG-29 is always at a disadvantage againist F-15 or Su-27.
AndraxxusI agree, otherwise any appropirate answer to hewasahero will get ME banned from this forum.
AndraxxusAs a numbers guy, I am really curious about WHY F-35 is called bad, F-15/16 good, and F-22 phenomenal.. All F-22 lovers may trash my post all they want but;
Comparing F-15E vs F-22 and F-16C vs F-35A;
F-35 has 146,2% empty weight of F-16C.
F-22 has 138,1% empty weight of F-15E.
Wing area linearly contributes to drag, and Thrust directly counters the drag.
F-22 has 138% wing area of F-15E. It also has 121% Thrust.
F-35 has 153% wing area of F-16C. It also has 146% Thrust.
In thrust/drag department, all else being the equal (I am not saying it is, just making a point), F-35 is 4% inferior to F-16, and F-22 is 12% inferior to F-15E.
At their empty weights;
F-35 has 99,8% T/W of F-16C.
F-22 has 87,8% T/W of F-15E.
F-35 has 95,4% Wing Loading of F-16C
F-22 has 99,7% Wing Loading of F-15E.
Now I generated a term equalised fuel, based on aircraft’s SFC and Cd are all the same, wing area alone will dictate thrust is required to move the aircraft, and this thrust will be directly proportional to range. ie, if F-16C carries 27,87*X amount of fuel, F-35 will need 42,7*X, because its more draggy. Taking X=50, at this equalised weight;
F-35 has 99,1% T/W of F-16C
F-22 has 87,7% T/W of F-15E.
F-35 has 96% Wing Loading of F-16C.
F-22 has 99,8 Wing Loading of F-15E.
*I assumed F-22’s engine thrust to be 156kN. If anyone has better value I can input that, but I must say, F-22 needs 177,8 kN thrust from each engine to match F-15E’s T/W.
Heres the table;
[ATTACH=CONFIG]238846[/ATTACH]
Now according to these values, F-35 is much more closer to F-16 than F-22 is to F-15. Any assumption due to advances in technology (improved aerodynamics, improved SFC) that may benefit F-22 would F-35 even more.
Its true that F-35 looks ugly as sh!t, and F-22 is cool and looks more aerodynamic, but on numbers alone, it doesn’t give one reason WHY F-35 is underpowered, (it fares just as well as F-16, far better than F-22), or unmaneuverable (Very similar wingloadings and general layout and features).
On the contrary, F-22 looks clearly underpowered when compared to F-15E. Though addition of several aerodynamic features (negative stability, LE flaps etc) would offset this disadvantage, its important to remember F-35 has them too.
My point? Every claim about F-35 cannot dogfight (based on its heavy, or underpowered or have small wings) must also apply to F-22; either that or this claim is wrong.
AndraxxusNow that Andaxxus is here: would it be possible to arrange Greece as a protectorate of Ottoman ?
LOL, but there were proposals that Turkey is to undertake Greeces 1.6bil € debt or provide zero interest loan should Greeks accept, in the hopes of “earning the friendship of Greek people and turn the Aegean Sea into a sea of peace”. Since the offer is made by Kurdish People’s party, I would assume it is sincere, but if we look at the past few incidents, Greeks are simply too proud to accept any help from us.
Andraxxusi dont doubt your knowledge when it is about aerodynamic, but to be honest, iam very surprised that F-4E even on 30% fuel can out maneuver a su-27 at all fuel, what is their respective turn rate at these conditions ?
F-4E = When clean and at 33000lbs, It can susain 7,5Gs at 500 KTAS, equals to 16,7 deg/s. A Su-27S at full fuel load is limited to 6,65Gs, so turn rate at same speed will be 14,7 deg/s, limited by G load. Its true that making some calculations to Su-27 graphs will reveal that Su-27 will have its best turn sustain rate at around 775 km/h, at a higher 17,18 deg/s.
that surprised me alot, weren’t the empty fuel tank and pylon can cause a lot of drag?
Drag Index of each 370Gal without any other stores in nearby pylons is 27; 2×27+7(Basic F-16C drag index), so total drag index = 61.
-At DI=50 at 25000lbs, F-16 could still sustain ~18,6deg/s STR, have ~23,2 deg/s ITR, and have 800+fps climb rate.
-At DI=100 at 25000lbs, F-16 could still sustain ~18,4 deg/s STR, have ~23,1 deg/s ITR, and have 800+fps climb rate.
Those numbers are for block 50, btw. Blk40 has around 3% less thrust.
It may only be for a slight margine.
Once the Su-27 fuel Level goes Down just a little, it gains the upperhand.
Exactly. That was my point, there will be conditions F-35 will certainly be more maneuverable than F-16 or vice versa… What matters is IF F-35 can match F-16 with fuel for similar range, which we don’t know anyway.
AndraxxusGiven the need of the hour, would Greece ever think about selling some of their top assets (Block 52 and Erieye) to generate some cash flow for the armed forces?
No. According to Thanos Dokos, an analyst; “a consensus in the country that there is a threat from Turkey and that we need to be able to defend ourselves against it. This is not Belgium or Portugal”.
Irrelevant of the Greece’s actual ability to defend againist a Turkish invasion even in their better days, people would object heavily againist shrinking their military. In any case, their F-16 will fly less, maybe only a percentage will be fully maintained and operational, but they will want to maintain their fleet strength on paper.
better to sell them to stave off bankruptcy. There are a lot of countries right now looking for military gear.
Greeks are not THAT bankrupt. They still have 89billion € cash liquidity from European Central Bank, they can easily pay their current (1.6 billion) payment to IMF. They are simply chosing not to, because -in short- they think they will not be able to pay all their depts in long term.
AndraxxusFake or not, such claims are not useful in any way.
The test pilot flying the F-35 makes it very clear that the new jet, even in its ideal configuration without any external stores, was no match against a Block-40 F-16C in a less-than-ideal configuration with a pair of under-wing fuel tanks:
It fails to answer even what was the fuel load of both aircraft? To what range can they reach with that fuel? Without this critical information, any comperison is pure BS, with ZERO scientific value. To exegarate;
Block 40 with two empty underwing tanks and half internal fuel, can far outmanuver a clean Su-27 with full fuel load.
Block 40 with two full wing tanks and full internal fuel can be easily outmanuvered by an F-4E and 30% fuel load.
also an F-4E can outmanuver a Su-27 *in sustained turns* if F-4E is at 30% fuel, and Su-27 is at full. Based on this fact, it would be very silly to claim F-4E is more maneuverable than Su-27.
I am completely ignoring the conditions or limitatons during the alleged dogfight.
AndraxxusAnother photo of that monster payload:
@TR1: Was the picture from take-off or landing? I ask because -in theory- original Su-27S cannot land with that payload, but deployed flaps, and lack of afterburner in the image made me wonder.
PS: 2500 kg on each wing and 2500 kg on fuselage made me remember some discussion about whether Su-30/35 could carry 2 (or 3) BrahMos -or similar- missiles. Granted its distributed between pylons, but IMHO it wouldn’t be too hard to make a special adapter that uses both wing pylons. Surely Brahmos is longer by 72% compared to FAB-1500, but its way more aerdynamic than 3 bombs. With strict speed and G limitations, its truly a feasible option.
AndraxxusThat is a serious payload:
3x KAB-1500L = 3x1525kg
6x FAB-500M62 =6x 500kg
2x R-73 = 2x 105kg
Makes 7785 kg of weapons load, excluding pylons, adapters and MERs. Impressive indeed.
AndraxxusI’d expect it reduces the cost of production and maintenance somewhat.
Well, canopy material is several times more expensive than sheet metal. Manufacturing a few additional dies and molds is way cheaper than wasting twice material for each aircraft. With more expensive replacement part, maintenance will also be more expensive, but parts commonality is an advantage nontheless.
Quick q;
Does the enlargen canopy of M2 have any thing to do with less drag issue?
Generally speaking, any increase in wetted surface area increases drag. Larger canopy increases wetted surface a little, and unless its so efficent that it reduces Cd, it adds to drag. It should be negligable though.
AndraxxusMaking a common airframe and canopy for both single-seat would make sense if they had made the rear seat fully modular; ie, rear seat/cockpit replaceable with bolt-on fuel tank or viceversa. This way any single seat aircraft could transform into a twin seat a/g or twin seat trainer as simple and quickly as replacing a pylon.
Without such feature, its all senseless; only simplifies engineering solutions and nothing else.
AndraxxusBah! F-32! Should have been F-24, or F-25 – regardless of whether the X-32 or X-35 was picked.
Agreed. Excluding some exceptions (like F-111 or F-117), F-1xx mostly represented 2nd gen fighters, F-x represented 3rd gen, F-1x 4th. F-2x was supposed to be 5th gen, but F-35 designation simply ruins it.
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