Amiga500Looking at FM data; a clean F-15E at 39000 lbs cannot even generate 1G lift to maintain level flight at M2.0 60k feet. That aircraft has 312 kg/m2 wing loading and 1,485 static T/W. And someone is telling F-22 can generate 5Gs with a) inferior T/W b) higher wing loading c) higher drag? All because of the insignificant features embedded in it? Let me be more scientific;
density of air at 60k feet = 0,1 kg/m3 IIRC; Speed of sound = 293 m/s
F-22 flying bare clean, empty = 19700 kg
5G= 996285 Newtons = 0,1 *1/2 *CL*293^2*78 Right?
That gives us Cl of 2,97 for an F-22 (flying empty not even 1kg of fuel payload or ammo, not even pilot) to pull 5Gs at M2.0 60000k feet. What kind of airfoil gives such Cl at M2.0? None. Not even a third of it. 2,97 = Thats a scientific impossibility.
Are you not missing a 2 in there…?
V = Ma
M = 2
a = 293 m/s
so…
L = CL * 0.5*rho* V^2 * S
CL= L/(0.5*rho* V^2 * S)
CL = 996285/(0.5*0.1*586^2 * 78)
CL = 0.74
Amiga500So which will have the best kinematics between clean F35 and Rafale + 2x1000L bombs + 1 centerline supersonic tank?
Assuming a Rafale tries to fight with the tanks/bombs or without the tanks/bombs?
Amiga500What do you think?
Correct – but again, we’re back to the circular argument.
Every fighter with drop tanks can rapidly (as in, over a couple of seconds) change their fuel fraction, total weight and their aerodynamic drag.
The F-35 cannot.
So, yes, a “heavily outloaded” Rafale/EF/-15 won’t be able to match the performance of a clean F-35… but the pilot can choose to accept a mission kill if it means survival. The F-35 pilot *may* be in a situation where they wish to do the same, but the effect of jettisoning bombs is much less pronounced… which may lead to loss of the airframe.
Its all hypothetical arguments based on hypothetical situations and biased by everyone’s own opinion. Pretty much all the arguments have at least some degree of validity.
Amiga500I didn’t, because lift effect from the fusalage is typically added to the “wing area”. F-35A doesn’t actually have 42,7 sqm wings. If you calculate from schematics, it has 5,2m root chord, 1,5m tip chord, and 3,7m span for each wing; [(5,2+1,5)/2*3,7]*2 makes 24,79 sqm. Same goes for F-22, Su-27 or F-15 also.
Oh no-no – you can’t do that!
The fuselage will contribute, but nowhere nearly as much as an equivalent planform area of proper wing…
I wonder where the 42 m2 comes from… I see it listed on numerous websites, but as you say, it doesn’t correspond to wing area. Is it just the total planform area of the wing-body?
Just roughly, taking [c= chord, s= span]:
cTip = 1.5m
cRoot = 5.2m
sTip = 5.35m
sRoot = 1.65m
@sCentre (the centreline) = 0m, the extrapolated cCentre would be 6.85 m
Then calc’ing that wing area gives 44.7 m2
Multiply that by the correction factor 0.9* pulls the effective wing area down to 40.2 m2
The conventional wing area is Se, below, but to include body lift, you take the overall planform area of an extrapolated wing and correct for effectiveness of the fuselage section
[ATTACH=CONFIG]226033[/ATTACH]
*if sRoot = 1.65 is considered the fuselage boundary and sTip 5.35, then sRoot/sTip == a0/S0 ~= 0.3… from the below graph, that gives a correction factor of ~0.9 [using middle line as F-35 is a relatively bluff body and not the extended slender missile body in the lower line]
[ATTACH=CONFIG]226034[/ATTACH]
Amiga500SNIP
Good stuff – all seems fairly logical. How did you fudge the effectiveness of the fuselage onto the wing lifting area; did you go with a planform area and then factor by 0.9?
One outstanding high-level assumption though; the F-16 leave the airfield with 6 AAMs and the F-35 leaves with 4.
Amiga500I more fear MiG-31 being modernized to a low SFC and super cruising at Mach 1.5, standoff bomber destroyer integrated into system 500 than a new airframe. A supplement to Sukhoi’s T-50 like F-15C Golden Eagle supplements F-22.
How do you define supercruise?
By any useful measure or yardstick, right now, the MiG-31 will fly significantly faster, for significantly longer, than the F-22 when the F-22 is “supercruising”.
Amiga500Ok, now we’ve established you’ve no clue about aircraft performance. It’s also clear you didn’t read the rest of the posts. The F-16 and F-15 turn performance at 15,000 feet was posted by me.
and…? so…?
What did the numbers say?
Did they say the F-16 or F-15 were not better than the F-35? Or did they not?
I’m also interested in seeing how you justify the Hornet being a representative aerodynamic performer relative to other platforms. It can point its nose very well, but it can do damn all else well. Even an F-22 knows to avoid a Subpar Hornet in a very low speed engagement.
It’s also clear that though the suspected comparison sustained turn configurations for the F-16 and F-35 are all over this thread, you have not read them either.
Amega, It’s really not profitable to discuss this with you, you need to have some details, facts. I’ve posted them previously and you refuse to look at the acceleration charts et al. Or is it that you can’t read them?
Its that not one of them refute my stated view!!
You’ve said you don’t know the weight and altitude of the F-35 – That is correct – I am not arguing with that at all….
Now, unless you think the F-35 KPP was at some altitude which is not remotely representative and that the F-35 will magically improve beyond the two teen fighters your pissing into the wind!
Your posting up stuff, but your not actually reading what I’m saying!
Amiga500And we are back here again, sustained turn performance. Again, did you read those posts about this from 2 weeks ago when you posted this fallacy last time. You were wrong then, you’re still wrong, and still posting this tripe. Here’s the argument:
You refuted nothing of my posts last time. Comparing the F-35 to the F/A-18 is incredibly silly given the Hornet is already a dog’s dinner when it comes to aerodynamic and kinematic performance.
If the JSF cannot beat the runt of the “4th gen” litter, then there is something shockingly wrong. As it is, its just seriously wrong.
I expect you will reply with the fallacious argument that equivalently laden F-16s/F-15s cannot turn better than the F-35, completely ignoring several basic facts:
1. If a (for example) F-16 had only 4 AAMs prior to the fight beginning, it would have fired off at least 1, probably two, prior to entering a turning engagement.
2. The same F-16 would have dropped any external fuel tanks prior to entering the turning engagement.
3. If this overworked example of an F-16 takes the option of jettisoning any A2G munitions, it then definitely has a superior kinematic performance to the F-35. Trading a mission kill for a possible outright kill.
4. If the, by now suffering from example fatigue, F-16 had more than 4AAMs, then it can ripple fire several to try and force the subsequent turning engagement on its terms. Well trained pilots understand the effects of storage on their platform aerodynamics and will consider that through the engagement.
Your other links there refer to comments aimed at others.
Amiga500Erm… on what basis have you made this informed, well reasoned conclusion?
The basis that a clean F-35 with a power:weight ratio of nominally ~0.85 can achieve similar sustained turn performance to a fighter with a similar nominal power:weight ratio that first flew about 55 years ago…
The basis that the KPP for acceleration have been effectively scrapped for the -C variant (when clean)…
The basis that such a short airframe with such a large internal volume is a serious fundamental obstruction to an optimal finesse ratio (regardless of what the wikipedia version of that equation may say for the uninitiated).
If you measured up the kinematic performance of an F-35 with 2x2000lb bombs and 4xAAMs, then compared it to other fighters of similar cost with 2×2000 lb boms and 4xAAMs – I would very much expect it to be found wanting.
[Note: NOT the comparison of a “fully laden” F-35 with 2x2000lb bombs and 4xAAMs to, say, a fully laden Rafale with 3×2000 lb bombs, 2x1250l tanks, 2xMk82s and 6xMICA….]
Amiga500And as the weak range increment with external fuel shows, something nasty happens to the aero efficiency above clean maximum weight.
Erm…. I’d argue something nasty is happening to the aero efficiency long before you go hanging stores off it 😀
Amiga500Just found this interesting article from defensenews.com referencing a just signed defence research pact between the US and UK:
When is any UK govt gonna wake up and realise the US military-industrial complex is buttf*kking them at every opportunity?
Its been this way for the last 70 years!
WAKE THE F__K UP!!!!
Amiga500The F-35 is the logical replacement for the Typhoon. It is a jack of all trades design, but given where the RAF’s force structure is going that is what it needs. The fact that the UK is a major participant in the program helps as well.
Nah. Gripen NG is logical replacement for the RAF.
It keeps unit numbers sufficiently high to allow deployment of relevant numbers while retaining a sufficient reserve at home.
Amiga500They were heavily involved in the very early days of the programme, shared and exchanged information with the other partners so they would have received a certain amount of knowledge and know how, and they’re hardly going to forget all about that after they left… It’s pretty self-explanatory, isn’t it not?
And do you think that BAE/DLR/CASA learned nothing from the company that designed/built the Mirage 2000 and the Mirage 4000?
Amiga500They were definitely committed in cooperation with the Tornado and Eurofighter programmes, yet they pulled out and went their way – after getting what they needed that is. Taking those situations into account, as well as requirements, I wouldn’t have France on-board the third time around. Twice bitten thrice shy. I’d rather stick with Germany, Italy, Spain and I would most certainly attempt to push Sweden to get involved. However, it’s requirements for the latter so I wouldn’t bank on them joining.
Are you nuts?!?!
The French were completely right with Rafale and (once again) the MoD and politicians in the UK didn’t know their **** from their elbow.
Lets examine the disagreements:
– carrier capable? Would have worked with the QE2 and left the RN not reliant on the F-35. D’oh.
– A2G from day1? Would have helped in Mali, in Afghanistan and in Iraq. Whoops.
– Dimensions? EF-T OEW = 11 tonnes, RafaleM 10.2 tonnes. Length: 16/15.25, wingspan: 10.95/10.8
Irreconcilable differences there.
– workshare? Could have been sorted, even dupilication of work would have been cheaper than the alternative.
Amiga500What do you mean by small arms – assault rifles and light machineguns – They are hardly a problem for both aircraft?
An F-16 can no more take a “badly” placed round from an AK-47 than you or I.
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