F-6A (F4D) Skyray and F5D Skylancer

Jschmus · July 28, 2004, 08:55:50 PM

Greg Goebel just posted his history of the F4D Skyray. A lot of it looks familiar, but there is some information I hadn't read elsewhere.

Air Vectors F4D Skyray

KJ_Lesnick · July 08, 2008, 05:28:01 PM

The F4D Skyray was quite an impressive airplane with an extraordinary thrust to weight ratio for it's day, light wing-loading, and some instability yielding extraordinary maneuverability (however, difficult to fly), and it even proved itself capable of supersonic (marginally) speed.

One thing about the plane that strikes me as coming up way short was it's speed. It really wasn't all that fast, owing largely to a blunt nose, and probably not the most efficient inlets in the world.

While I have heard explanations as to the blunt-nose being due to it being harder for radar to see through a sharp nose, and supersonic speed was an afterthought, planes like the F-90, the F3H-1 (The F3D flew around the same time as the F4D - 1951) had sharp nose and managed to successfully integrate radar.

When you factor the fact that had the plane been faster, it would have also had a faster rate of climb (enabling it to perform it's mission better) -- and the J-40 which to the best of my knowledge was to power it, was believed to have been a lot more powerful than it turned out, and the J-57 was MORE than able to achieve supersonic flight, the design would have been better with a pointy nose, slightly modified inlets and a few other modifications to enable it to achieve supersonic-speed. The F5D (albeit powered by a different engine) kind of proved this as well, however the F8U was comparable in performance and rendered it unnecessary...

However if a plane like the F-4D had performance comparable with a faster plane like the F-100, back in that era... how would it have affected history?

Kendra Lesnick
BTW: Would it have affected the F-4 development

dy031101 · July 08, 2008, 07:35:43 PM

From what I've heard, the problem isn't so much as its speed but its relatively poor endurance (which makes it a relatively poor multi-role aircraft; soon the USN decided that it wasn't sophisticated and/or expensive enough to remain specialized).

Of course, aerodynamic refinement could potentially raise endurance as well.

Weaver · July 08, 2008, 07:54:51 PM

Apparently, when they picked the Crusader over the Skylancer, somebody from the flight-test team rang up Ed Heinemann and said "why did they pick that when your's is two-tenths of a mach faster?".....

Polly Ticks wins again......

dy031101 · July 08, 2008, 08:09:42 PM

Quote from: Weaver on July 08, 2008, 07:54:51 PM
Apparently, when they picked the Crusader over the Skylancer, somebody from the flight-test team rang up Ed Heinemann and said "why did they pick that when your's is two-tenths of a mach faster?".....

Wasn't the Skylancer to have been able to launch Sparrow II? Could its radar have been adopted for Sparrow III instead?

Lawman · July 09, 2008, 01:15:32 AM

If the Skylancer derivative had flown a bit earlier, and perhaps even pre-empted F-4D production, then things could be very different! If Douglas can get the Skylancer ready in time, i.e. some time in 1956 (i.e. not long after the first Crusader flight), and make a good proposition to the USN, then the Crusader may not make it into service. Vought would then turn their attentions to replacing the F-3H Demon, where McDonnell would then play up the 'two engines = safety' line, and the Phantom may win; this could then result in the Crusader becoming an orphan! The Skylancer then flies alongside its cousin, the A-4 Skyhawk, from all the Essex class carriers (which the Phantom is too big for). The Skylancer also benefitted from the stretching of the F-4Ds fuselage, which was partly to allow for the afterburner, but I think it also made some more room for fuel. Perhaps Douglas could even buy time and switch to the even larger J-79 engine (since the airframe did have some growth margin built in), and boost the Skylancer's speed a bit more.

This could actually have an unintended result - if the '50s Skylancer beats the Crusader, then by the late '60s it would be pretty outdated, and perhaps there would even be calls for a new lightweight fighter for the mid '60s! Perhaps Vought, having lost the '50s competition with the Crusader, decide to re-think; they decide that the ruggedness of the Skylancer was decisive - a weakness in the variable-incidence wing of the Crusader. They decide to revamp the Crusader, with a new wing design, and a bigger radar in the nose, with the intake moved back a little bit (sort of halfway between an A-7/F-8 nose and an F-16 nose/intake design). The result is a multi-role aircraft, with a very strong wing, allowing plenty of hardpoints; and uses a license-built derivative of the British Spey engine, but a bit bigger (grown up to 17,000 dry and 24,000 in reheat). The aircraft is sold to the Navy on the basis that is provides an aircraft that can: carry as many weapons as the A-7 would have, can operate from the Essex class carriers, and can reach Mach 2, while carrying only slightly fewer missiles than the Phantom. This would enter mass production in the mid-to-late '60s, and be produced in huge numbers; perhaps this would give the Esssex class carriers a new lease on life - they did have life left in them, they just lacked a modern fighter, since the Crusader was far from modern by the '70s! Perhaps this would see the Essex class maintained or even brought back into service in the '80s as part of Reagan's fleet build-up.

Maverick · July 09, 2008, 02:27:07 AM

Guys,

Whilst I'm not wading into this debate or alternate history, I still think that 'correct' designations would help quite a bit. The Skyray is F4D in the pre-62 scheme, it wasn't an F-4D (which is the AF's ground attack dedicated Phantom in post 62 times).

The F3H did get the F-3 designator post 62, but it wasn't an F-3H, it was an F-3 or -3B or -3C dependent on the pre 62 version.

Regards,

Mav

GTX · July 09, 2008, 02:58:48 AM

QuoteOne thing about the plane that strikes me as coming up way short was it's speed. It really wasn't all that fast, owing largely to a blunt nose, and probably not the most efficient inlets in the world.

Interesting that you say this, when the prototype XF4D-1 captured the world absolute speed record of 752.9 mph (642 knots) and that the F4D was the hottest plane the Navy had at the time. Without external stores, a clean "Ford" could be climbed initially at 540 knots at 70 degrees nose up angle!!!

Regards,

Greg

Weaver · July 09, 2008, 03:52:19 AM

Quote from: Lawman on July 09, 2008, 01:15:32 AM
If the Skylancer derivative had flown a bit earlier, and perhaps even pre-empted F-4D production, then things could be very different! If Douglas can get the Skylancer ready in time, i.e. some time in 1956 (i.e. not long after the first Crusader flight), and make a good proposition to the USN, then the Crusader may not make it into service. Vought would then turn their attentions to replacing the F-3H Demon, where McDonnell would then play up the 'two engines = safety' line, and the Phantom may win; this could then result in the Crusader becoming an orphan! The Skylancer then flies alongside its cousin, the A-4 Skyhawk, from all the Essex class carriers (which the Phantom is too big for). The Skylancer also benefitted from the stretching of the F-4Ds fuselage, which was partly to allow for the afterburner, but I think it also made some more room for fuel. Perhaps Douglas could even buy time and switch to the even larger J-79 engine (since the airframe did have some growth margin built in), and boost the Skylancer's speed a bit more.

This could actually have an unintended result - if the '50s Skylancer beats the Crusader, then by the late '60s it would be pretty outdated, and perhaps there would even be calls for a new lightweight fighter for the mid '60s! Perhaps Vought, having lost the '50s competition with the Crusader, decide to re-think; they decide that the ruggedness of the Skylancer was decisive - a weakness in the variable-incidence wing of the Crusader. They decide to revamp the Crusader, with a new wing design, and a bigger radar in the nose, with the intake moved back a little bit (sort of halfway between an A-7/F-8 nose and an F-16 nose/intake design). The result is a multi-role aircraft, with a very strong wing, allowing plenty of hardpoints; and uses a license-built derivative of the British Spey engine, but a bit bigger (grown up to 17,000 dry and 24,000 in reheat). The aircraft is sold to the Navy on the basis that is provides an aircraft that can: carry as many weapons as the A-7 would have, can operate from the Essex class carriers, and can reach Mach 2, while carrying only slightly fewer missiles than the Phantom. This would enter mass production in the mid-to-late '60s, and be produced in huge numbers; perhaps this would give the Esssex class carriers a new lease on life - they did have life left in them, they just lacked a modern fighter, since the Crusader was far from modern by the '70s! Perhaps this would see the Essex class maintained or even brought back into service in the '80s as part of Reagan's fleet build-up.

Not exactly the same thing, but have a look at my Vought-HSA Paladins on my Profiles thread, here:

http://www.whatifmodelers.com/index.php/topic,19781.0.html

KJ_Lesnick · July 09, 2008, 02:43:41 PM

Would the F5D Skylancer have done better in Vietnam than the F-8 Crusader?

Kendra Lesnick

MAD · July 09, 2008, 03:19:42 PM

Quote from: KJ_Lesnick on July 09, 2008, 02:43:41 PM
Would the F5D Skylancer have done better in Vietnam than the F-8 Crusader?

Kendra Lesnick

An interesting question and a big ask!

M.A.D

Weaver · July 09, 2008, 03:45:41 PM

Quote from: KJ_Lesnick on July 09, 2008, 02:43:41 PM
Would the F5D Skylancer have done better in Vietnam than the F-8 Crusader?

Kendra Lesnick

Depends if the service version ended up with a J-79 or J-57, and guns or rockets. With a J-79 and a reliable gun installation, it would have been superior. With a J-57 and (useless) rocket packs, it would have been roughly on a par with the Crusader, whose guns were chronically unreliable. Ironically, for all the talk of it being "the last gunfighter", the vast majority of the Crusader's kills in Vietnam were made with Sidewinder.....

KJ_Lesnick · July 09, 2008, 06:48:39 PM

Weaver,

Thank you for your assistance.

Just out of curiousity... which airspeeds did the F-8 tend to do best at (low, intermediate, high) in regards to sustained-G's and instantaneous G's?

Kendra

Archibald · July 09, 2008, 11:45:24 PM

I really love the F-5d Skylancer!

the "official" reason why it was rejected by the USN back in 1956 is aparently that the Navy feared "too much Douglas". The firm had lots of USN contracts, large chunks of carriers air groups were Douglas aircrafts.
Don't know if this story is a myth or not...

Weaver · July 15, 2008, 04:37:23 AM

Quote from: KJ_Lesnick on July 09, 2008, 06:48:39 PM
Weaver,

Thank you for your assistance.

Just out of curiousity... which airspeeds did the F-8 tend to do best at (low, intermediate, high) in regards to sustained-G's and instantaneous G's?

Kendra

Blimey - now you're asking.....

My reference books only cover the later generation of fighters, so I've no numbers for the F-8. It did gain ventral strakes in later versions to cure a high-speed snaking problem, so I'm guessing that directional stability might be the limiting factor at high AoAs. Certainly the high wing/low tail combo should avoid pitch instability. Don't know about pitch-up, but the wing sweep's not radical, so I'd guess not too much of a problem.