WESTLAND WYVERN T.F.1,

[Groggy]

WESTLAND WYVERN T.F.1, with a Rolls-Royce Eagle piston engine, achieved 455 m.p.h.
Gunston wrote that the R-R Clyde was tested and would have given (gave?) the Wyvern 500mph at sealevel.
I clearly remember reading that the top speed was 520mph. I assume at altitude but do not recall which engine. Can any one help with details

[merlin]

Working from Tony Buttler's Secret Projects, it states that R-R proposed concentrating on the 'Clyde' turbo-prop rather than the 'Eagle' piston engine. This meant an 'all-new fuselage'. The problem with the Eagle was that it was an undeveloped, but heavy, engine - leading to it being a heavy aircraft - the turbo-prop fighter version was 16,300 lb compared with 19,194 lb Eagle. Hence expectations of the Clyde version were high - in rate of climb, though the the top speed at 20,000' was unchanged!.
In the first half of '46, the option of the Armstrong Siddeley Python turboprop 'entered the picture'. Hence, three turbo-prop protypes were built and flown in '49 (two with the Python, and one Clyde), but further development of the Clyde was abandoned.
Interesting to compare the Wyvern with the Supermarine 391 also with the Eagle engine, the 391 weighed about 4,500 lb less for the torpedo version, with a max speed of 546 mph at 25,000'!
Hope this is of interest.

[GregP]

I believe the 391 was a paper exercise, wasn't it?

It would have been nice to have an actual, live 500+ mph production piston fighter in order to believe such things were possible. The current world record holder, Rare Bear, is a Grumman F8F-2 Bearcat that has virtually nothing in common with a production Bearcat, and it made 528+ mph on 4,500+ HP as the current world record for propeller-driven, piston-powered aircraft.

It has had the wings recontoured, has fairings all over the place, has a cut-down canopy, a special propeller airfoil to get the speed out of it, and all sorts of "speed merchant" tricks to go that fast.

And we are talking here of an armed, production-quality aircraft with 1,000 less HP going slightly faster. Personally, I doubt it in the extreme. Otherwise, we'd have seen that performance by now from a racer that was "cleaned up" running that same HP or less ... and we haven't, even with 70+ years of more modern aerodynamic knowledge.

All the piston-powered planes going anywhere NEAR that fast have 4,500 - 5,000 HP on tap and are all but useless for anything except racing, and they only go that fast for a VERY short time .. and then require a one-year overhaul to do it again!

[Wuzak]

As you have pointed out before Greg, the speed record runs are held at low altitudes.

Aircraft such as the Type 391 (and yes, it was a paper exercise) had their maximum speeds at somewhat higher altitudes. At the low altitudes at which Rare Bear took the record WW2 fighters were pegged at around the 400mph level.

[GregP]

Duuhhhh .... a VERY good point, Wuzak! Somebody SLAP me [:I] ... I know you'll volunteer! :D

OK, at altitude, maybe.

And you're right. The P-51D went 437 mph at best altitude, but only about 387 mph or so at sea level.

[Groggy]

quote:Originally posted by GregP

Duuhhhh .... a VERY good point, Wuzak! Somebody SLAP me [:I] ... I know you'll volunteer! :D

OK, at altitude, maybe.

And you're right. The P-51D went 437 mph at best altitude, but only about 387 mph or so at sea level.


Hi
I agree about the piston planes, I am wondering how much jet thrust and how much prop power there was to estimate 500mph at SL?

[Trexx]

FYI, Stead Airport near Reno Nevada is 5,050 ft above sea level.

In 1989 I believe it was, the Rare Bear went 528 miles per hour there.

[GregP]

528.33 mph, 21 Aug 1989, Lyle SHelton, Grumman F8F Bearcat Rare Bear.

But ... you KNEW that! :)

[Trexx]

Hallelujah, Brother! :)
...had a special, fancy propellor among all the wonderfulness.
A cut and reshaped one off a C-130... The single most expensive part at cool three million dollars. Cha-Ching!