XF8U-3 Performance Comparison with F4H-1/F-4B (1 Viewer)

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Something about the fighters Vought built that I've always wondered about- why were they in general so hard to control, difficult to land on an aircraft carrier and successful at ACM? With two exceptions, of course. The Corsair was a scary airplane from what I've read; torque rolls, lack of forward visibility and bouncing off the deck and losing the wire until that bouncing issue got solved. But very successful in combat. The Pirate was a dud, as was the Cutlass, though I think the motors were the biggest issue for the F7U and not the design. The F-8 kicked ass in air to air, but had a high accident rate when around the boat. Again, visibility was an issue. I've read trapping on the Essex class with the hook clearance and such was part of the airplanes problems. I'd be interested in the number accidents on the smaller carriers vs. the big decks. Who knows how the Super Sader would would have done in combat. Again, I've read it did well in ACM, but how would it have panned out operating off the carriers? Was handling secondary to performance?
 
"Easy-handling" aircraft generally do not have the near-instant control response required for good air combat maneuvering.

Such excellent dogfighters generally were regarded as "twitchy" or "a real handful" for less-experienced pilots - but those same characteristics are what made for their excellent maneuverability.

It was only with the advent of combat-rated flight-control computers (especially when combined with fly-by-wire aircraft) that the combination of easy controllability throughout the flight regime and excellent air combat maneuverability was achieved on a regular basis.


The Cutlass also had a problem with its nose landing gear... the length required to get the angle-of-attack high enough for the required low take-off & landing speeds (especially with the weak engines it was stuck with) made for an easily-damaged set-up (often simplified as "weak nose gear").
 
Something about the fighters Vought built that I've always wondered about- why were they in general so hard to control, difficult to land on an aircraft carrier and successful at ACM?
Because its difficult to produce an aircraft that is able to land with ease aboard a carrier deck while simultaneously able to perform effectively as a fighter.
 
Again, I've read it did well in ACM, but how would it have panned out operating off the carriers? Was handling secondary to performance?

"Easy-handling" aircraft generally do not have the near-instant control response required for good air combat maneuvering.

Such excellent dogfighters generally were regarded as "twitchy" or "a real handful" for less-experienced pilots - but those same characteristics are what made for their excellent maneuverability.
The holy grail of fighter design is that rare phenomenon that is honest, easy to fly and land, and devoid of "gotchas", but an ACM champion nonetheless. Fokker D7, F6F Hellcat, and some say Hawker Hurricane, come readily to mind. Anybody got other candidates to stand on this podium?
 
I'll repost them today (it's 05:44 here so at some point in the afternoon it'll probably be up).
 
Here's the images I was posting earlier: The limit to which I could scale them down was based on the ability to read the numbers.

It's meant to look like the Standard Aircraft Characteristics pages since they're easy to read and are well laid-out.

This figure is for the F-4B and covers the early and middle operational operational variants: With differences in internal fuel capacity, possible airframe strengthening, as well as the fact that an RF-4B NATOPS manual from 1965 showed a g-limit of 8g ≤ Mach 0.72 and 6.5g > 1.05 Mach (rather than 8.5/6.5 for later F-4B variants), I guessed that the earlier F-4B's had a lower g-limitation (though that could be wrong).

PhantomII-SAC.jpg


I computed the weights for both fuel-tank arrangements used aboard carrier-based F-4B's (the USMC did sometimes operate F-4's with 3 x external-tanks).


Here's the data for the XF8U-3 and F8U-3: Much of the data from the XF8U-3 came from Tommy Thomason's SAC sheet, with the F8U-3 data coming from the last cited weight figure of 39551 lb. After contacting Mr. Thomason as well as computing the weight, it seemed that this figure most likely was with 3 x AIM-7C only: Since this aircraft never entered operational service, there's more guesswork here than with the F-4B which has information that is lifted out of a number of sources which includes NATOPS manuals (albeit from an RF-4B), an F-4 Ordinanceman Manual (includes the empty weights, fuel weights of different sub-variants, weaponry, and pylon weights). Much of the data comes from the XF8U-3 preliminary flight manual, and information inferred from a NATOPS F-8 pilot's pocket checklist, and an F-8J flight-manual.

The hardest thing to determine were stall-speeds (which set the maneuvering limits) because much of the information available discussed performance in the landing configuration with the exception being a flameout landing approach which appears to be done at high-speeds with speed brought down to 1.15-1.22 Vs once touchdown is assured (With the performance of the airplane being well-regarded, I made a bit of an assumption that 1.15 Vs was probably unlikely and 1.2-1.22 Vs were most likely correct, and this is why there's two figures listed for stall/corner velocity). Since the droops were similar in design to the F-8J, I operated with the presumption that their extension would reduce stall-speed by 5 kn. on the XF8U-3 at design-weight; then extrapolated those figures based on weight differences.

CrusaderIII-SAC.jpg


The landing weight was lighter than I expected since there were some tests with stall speeds computed for 29000 lb. (which I assumed were landing weights), but the only way I could get the weight that high would be if I assumed the plane was carrying over 3000 lb. of gas onboard when landing (which seemed implausible): While there was some guesswork (i.e. I'm not sure if the boarding weight was 200 - 247 lb., but I used the latter since it was used on the F-4B), even with the assumption of ordinance retained when coming aboard (this applied for the XF8U-3 figures, and there are quite a number of images of F-8's returning with missiles onboard), something that didn't apply with the F-4B weight calculations (though many pictures showed F-4's coming aboard with missiles onboard).

One of the estimates was based on the aircraft carrying a gunpack since there were proposals of designing the aircraft to carry a semi-submerged store under the fuselage which was also proposed to the RN:FAA which would have used a Rolls Royce Conway in lieu of the J75. This semi-submerged store could be a special weapon (at least in the USN), an external tank, or a gun-pack. While I'm not sure if the USN had any interest, it stands to reason that, if problems with missiles became an issue, it would have been very easy to equip into a design (Since I have no idea what the proposed gunpack was to weigh since it was never built, I used the SUU-16 as a baseline. For comparison, I also listed weight figures for the F-4B proposal with a SUU-16 as well).
 
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Zipper,

Realize that the RF-4B was a USMC only (46 made) aircraft and it did not carry AIM-7s. The last 12 were built on the F-4C frame (different wheels, wheel wells, and wing mods). The Reece versions of the F-4 had only a terrain following radar, smaller and lighter than the missile carrying version (probably accounts for a different Max G load however later versions could be beefed up to take more).

Cheers,
Biff
 
Realize that the RF-4B was a USMC only (46 made) aircraft and it did not carry AIM-7s. The last 12 were built on the F-4C frame (different wheels, wheel wells, and wing mods). The Reece versions of the F-4 had only a terrain following radar, smaller and lighter than the missile carrying version (probably accounts for a different Max G load however later versions could be beefed up to take more).
Oh, so all of them were capable of taking 8.5 ≤ 0.72?
 
Oh, so all of them were capable of taking 8.5 ≤ 0.72?
I'm not sure which models you mean by all of them. The last 12 RF-4Bs the USMC got were slightly different airframes based on the RF-4C. May / probably have had different G limits. I would guess that the light nose of the Reece version might have allowed greater G loading. Take that with a grain of salt.
 
BiffF15 BiffF15

I was talking about all the the F-4B frames (excluding the RF-4B's).
 
You quoted a NATOPS manual regarding the RF-4 in post #92. I was basing my replies off that and assumed your diagram was from that. My bad.
Well, I figured the weight changes between the early F-4B's and later ones were due to a load-factor change, but if the first RF-4B's were built to lower structural standards, then it's possible than the 8g L/F figure might very well have not represented the F-4B's.
 
Oops, isn't that back-to-front? Normally a weight increase without extra structural strengthening results in a load factor reduction.
Not if the extra weight were load-bearing components to reinforce stuff.
 

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