Spitfire Variants

[GTX]

Hi folks,

Looking for information on rare Supermarine Spitfire variants (either one-offs or paper projects). I am especially interested in any possible radial engined proposals.

Regards,

Greg

 

[smurf]

"Spitfire the History" by Morgan and Shacklady is the ref. Try Abebooks.com
I know there was a project for a Rolls Royce Eagle H engine version.

 

[Nick Sumner]

Eagle engined Spitfire...???? i mustv missed that one..cool...any references?

Supermarine 391 - more of a Spiteful development that a Spitfire.

 

[red admiral]

Spitfire with floats.

There was a proposal to put a R-R Crecy in place of the Merlin. 550mph was expected when the 2-stroke thrust (and 4000hp ish) was factored in.

 

[smurf]

Nick S said

Supermarine 391 - more of a Spiteful development

and is quite right. I was interpreting the request a bit loosely. There is a 3-d in Spitfire a History and that's my excuse. I think I remember a butterfly tail? I can't get at my aviation books to check at the moment.

RA said

Spitfire with floats.
There was a proposal to put a R-R Crecy in place of the Merlin. 550mph was expected when the 2-stroke thrust (and 4000hp ish) was factored in.

a. You didn't mean both at once?
b. 550 mph must be getting near the Spit's critical Mach number? Again, I can't check. Considering how hard it has been to push the piston engined speed record over 500 mph, I'm doubtful of 550mph, 4000 hp + thrust or not, especially in combat trim.

Note that the 3-d LD floatplane is the Mark V; the photos are the Mk IX version.

 

[red admiral]

Not both at once.

550mph should be below Mc for the Spitfire's wing. Going from memory it was 12% - 9% chord thickness, so should be reasonable at this speed. NACA wanted a high-speed test plane in the mid-30s with RR "R" and 9% wing. Expected about 550mph. The Type 391 with Eagle 22 was expected 550mph or so.

No one has really tried pushing the piston-engined record. Fairly easy to do better than RareBear. Some guys are building a Napier Heston replica so we might see it beaten yet...and some French guys going for a supersonic prop job.

 

[smurf]

From memory
Type 391 - Spiteful wing?

No one has really tried pushing the piston-engined record.

no, but the souped up racers with 3000+ hp don't get above 500mph, so I'll keep my doubts about 550 from a piston-engined combat plane. It's a 20% + increase in top speed for a Spitfire, 10% for Spiteful. People were quite optimistic at that time with speed estimates.

 

[red admiral]

I think the 391 was using the laminar flow wing.

The Reno racers operate at sea level. 550mph at 20,000ft is considerably easier.

The 3500hp Eagle should be more than enough to reach 550mph with the Spiteful. My theoretical speed is 558mph, but this doesn't take into account the loss of prop efficiency. Even so, I think the 4000/5000hp Crecy + considerable thrust can make up for this.

 

[frank]

Any other info on the French supersonic prop a/c?

Not both at once.

550mph should be below Mc for the Spitfire's wing. Going from memory it was 12% - 9% chord thickness, so should be reasonable at this speed. NACA wanted a high-speed test plane in the mid-30s with RR "R" and 9% wing. Expected about 550mph. The Type 391 with Eagle 22 was expected 550mph or so.

No one has really tried pushing the piston-engined record. Fairly easy to do better than RareBear. Some guys are building a Napier Heston replica so we might see it beaten yet...and some French guys going for a supersonic prop job.

 

[frank]

Yeah, a Spit with a radial! Maybe a Hercules or even a Centaurus! That's as good as the radial Mustang drawings running around!

Hi folks,

Looking for information on rare Supermarine Spitfire variants (either one-offs or paper projects). I am especially interested in any possible radial engined proposals.

Regards,

Greg

 

[red admiral]

Spitfire with a radial makes little sense as there is more or less no way it would fit. Probably increase the frontal area by a factor of 2-3. Not enough fuselage behind to support it either I imagine.

 

[GTX]

Spitfire with a radial makes little sense as there is more or less no way it would fit. Probably increase the frontal area by a factor of 2-3. Not enough fuselage behind to support it either I imagine.

I didn't say that it did occur or would make sense, I am just interested if there was a proposal for such a version. I ask since I have seen reference to a Radial engined Hurricane - One of several schemes during 1941 investigating alternative power plants for the Hurricanes in second-line duties to alleviate possible shortages of the Merlin involved the Hercules radial.

See http://www.k5083.mistral.co.uk/PROJECTS.HTM for more info (and details of other Hurricane proposals).

Regards,

Greg

 

[smurf]

The Hurricane was quite a bit 'beefier' than the Spit.

 

[Archibald]

Check Le Fana de l'aviation of this month! There's a nice article on the "Speed Spitfire" (highly modified mk1 to atempt breaking the world speed record in 1939).
Three month ago there was also a good article on float Spitfires...
God, I have to buy a scan one day!!!!!!!!!

 

[GTX]

God, I have to buy a scan one day!!!!!!!!!

Yes you do!!!

Regards,

Greg

 

[elmayerle]

Spitfire with a radial makes little sense as there is more or less no way it would fit. Probably increase the frontal area by a factor of 2-3. Not enough fuselage behind to support it either I imagine.

I wouldn't be totally certain of that. The Japanese did such an adaptation well enough in converting the Ki-61 to the Ki-100. It would take some care and some careful looks at local flows, to make certain there were no causes for extra drag that way, but it would not be impossible.

 

[Antonio]

The Japanese did such an adaptation well enough in converting the Ki-61 to the Ki-100

And the Ki-100 was a superb fighter.

 

[frank]

IIRC, the USSR had a number of airframes that were fitted with either type engine, as was one version of the Hawker Tempest (II, maybe?) as well as a couple of proposals from NAA for radial versions of the P-51H & there is a drawing from some air racer owner or pilot or similar with a proposal, at least at one time, to strap an R-2800 on a Mustang. A Sea Fury prototype was fitted with a Sabre & also a Griffon. The Germans were also using both types on the same airframes as well. To go from a a vee to a radial or the other way is not impossible, or even that difficult or detrimental in many cases. There are more types that have been done that way than one can imagine if it's given some thought.

Spitfire with a radial makes little sense as there is more or less no way it would fit. Probably increase the frontal area by a factor of 2-3. Not enough fuselage behind to support it either I imagine.

I wouldn't be totally certain of that. The Japanese did such an adaptation well enough in converting the Ki-61 to the Ki-100. It would take some care and some careful looks at local flows, to make certain there were no causes for extra drag that way, but it would not be impossible.

 

[smurf]

Consider the Spitfire MkI weighed about 5000 lb empty, with an early Merlin weighing about 1500lb capacity 27 litres I've not got a figure for width
Spitfire MkXIV weighed 6600 lbs empty, with the Griffon weighing about 2000 lb capacity 37 litres. Again no width, but estimating from a 3-view with a scale, no more than about 2'6"
Its wing area was about 240 sqft
Tempest V weighed 9100 lb empty wing area 302 sqft the sabre weighed about 2400lb
Centaurus weighed 3400lbs diameter 55 ins capacity 53.6 litres

How do you put this quart into this pint pot?

 

[frank]

How do you put this quart into this pint pot?

Same way Messerschmitt put a BMW on the 109 & NAA proposed to put the R-1830 or R-2800 on the P-51H or maybe the way Kawasaki created the Ki-100.

Consider the Spitfire MkI weighed about 5000 lb empty, with an early Merlin weighing about 1500lb capacity 27 litres I've not got a figure for width
Spitfire MkXIV weighed 6600 lbs empty, with the Griffon weighing about 2000 lb capacity 37 litres. Again no width, but estimating from a 3-view with a scale, no more than about 2'6"
Its wing area was about 240 sqft
Tempest V weighed 9100 lb empty wing area 302 sqft the sabre weighed about 2400lb
Centaurus weighed 3400lbs diameter 55 ins capacity 53.6 litres

How do you put this quart into this pint pot?

 

[smurf]

All things may be possible. Not all things are desirable. The Merlin at 27 litres was a very good engine, as powerful as many (replaced by radials) half as big again, and the Spitfire was designed to be a close fit. Don't forget that apart from the structural problems, the pilot needs to see past the engine.

 

[red admiral]

If you simply want to go faster just use one of the Merlins modified by Derby which produced up to 2640bhp

We see attached the Fiat G.57 with Fiat A.83 RC52 Vortice engine, only slightly down on horsepower vs the DB605 (1250hp vs 1350hp) but a reduction in maximum speed of 170km/h. The G.55 is considerably larger and heavier than the Spitfire and so can take the radial or DB603

 

[frank]

Forward vision on a number of a/c, regardless of engine type, is restricted, at best.

All things may be possible. Not all things are desirable. The Merlin at 27 litres was a very good engine, as powerful as many (replaced by radials) half as big again, and the Spitfire was designed to be a close fit. Don't forget that apart from the structural problems, the pilot needs to see past the engine.

 

[Jemiba]

There were quite a number of designs, were the view from the cockpit obviously
didn't matter, even for carrier based aircraft. Just remember the F4U Corsair, or
the Blackburn Firebrand, which started life as a Sabre (inline) powered interceptor,
larger, but with similar lines as the Spitfire and ended up as a radial powered
torpedo attack fighter. So I could imagine, that, there were thoughts about a radial
powered Spitfire, too, at least as a stop gap against a shortage of Merlins, similar to the
genesis of the Ki.100.

 

[smurf]

Again..

 

[frank]

Changing thrust lines doesn't always require major design changes. Look at the BF-109X & Ki-100 & others. Raising the radial that high on the Spit is ridiculous. The fuselage of the 109X was widened, & probably made deeper tho. I don't think the Ki-100 was altered that much & as I understand, was a fine performer

Again..

 

[Nick Sumner]

Red Admiral, is that a torpedo the Fiat G57 is carrying? If so, what sort is it?

 

[smurf]

Raising the radial that high on the Spit is ridiculous

Maybe. So, some think, is the idea of putting a radial on a Spit at all. Seriously, shortage of engines was met by having more Merlins made in USA, which was presumably easier than redesigning the Spit for an existing (American?) radial. There were no radial Spit projects. Shall we leave it at that?

 

[smurf]

Sorry, I couldn't resist this:

Look at the ... Ki-100

 

[red admiral]

The G.57 is carrying a "silurroto" or lightweight 680kg torpedo.

Not Attached is G.55S with 450mm torpedo because file is too big and Re.2001

Re.2005 and Re.2001 could also carry these weapons on the central 1000kg hardpoint.

 

[GTX]

Folks,

I fear I may have raised a controversial issue with my initial post. I didn't want it to turn into an argument over whether the idea of a radial engined spit was right or wrong. I simply was interested in knowing about rare spitfire variants (especially those that never went past the drawing board) in general and if there was any consideration of a radial engined variant. I asked since there were radial engined studies of many other merlin engined aircraft - e.g. Hurricane as shown earlier, Fairy Battle.

Regards,

Greg

 

[frank]

You know, regarding the 'robustness' of an airframe to handle a radial engine installation, ISTR reading somewhere that an air race pilot, Greenamyer, IIRC, some time back wanted to take a Cessna 210 Centurion & install a Merlin engine on it for air racing. So, taking a 300HP light airplane & installing a huge V-12 Merlin, well, there's gotta be a way to do it. I understand Cessna squashed his idea.

 

[smurf]

'robustness' of an airframe to handle a radial engine

Never mind the power, think about the weight.

 

[frank]

I am thinking of both issues. You can't separate the two.

'robustness' of an airframe to handle a radial engine

Never mind the power, think about the weight.

 

[smurf]

Frank said

I am thinking of both issues. You can't separate the two.

In the sense that you need to consider both, I agree. But the problems that arise are different.
Imagine an airframe designed to take, say, a 1000 hp Merlin. Increasing the power 'by magic' with improved fuel, better gas flow whatever makes you consider the stresse due to a greater 'pull' on the airframe. But putting in a substitute engine, say 50% heavier, means you have to consider the balance in the air, on the ground; whether the mountings are strong enough, a whole range of additional factors before you even start the engine. That's really what I meant. I can imagine the Cessna tipping on its nose on hitting a bump taxying, if it got that far

 

[joncarrfarrelly]

I think the 391 was using the laminar flow wing.

The Reno racers operate at sea level. 550mph at 20,000ft is considerably easier.

The 3500hp Eagle should be more than enough to reach 550mph with the Spiteful. My theoretical speed is 558mph, but this doesn't take into account the loss of prop efficiency. Even so, I think the 4000/5000hp Crecy + considerable thrust can make up for this.

Eagle 22 horsepower at 19,500' was 2,410 at 3,300 rpm and as it weighed 3,900 pounds and measured 135.5" long X 43.4" wide X 50" high it aint' gonna fit on a Spitfire or Spiteful.

Crecy output in the 4000/500hp range was purely theoretical and based on single cylinder tests.

Cheers, Jon

 

[red admiral]

The Supermarine type 391 was a fair bit larger than the Spitfire or Spiteful.

Two images at the bottom here.

The Eagle 22 might be giving 2410hp at that time (when btw?) but that figure could be rapidly improved considering the engine size. Derby had a Merlin running at 2640hp in 1944. The Eagle being about 70% larger should be able to beat this easily with a bit of fiddling.

 

[smurf]

I'm sure the diagram in Morgan & Shacklady had a butterfly tail?
I'll try to find my copy

 

[frank]

Really?? Being a pilot as well as mechanic, I never considered those points! I've even worked on & flown a/c converted to different/bigger engines, (only light a/c, mind you), so, as I indicated, I have an idea of what's involved. Assuming the story about the Cessna 210 is true, I would think this guy had thought it thru, as I believe it was Darryl Greenamyer, not some race pilot wannabe/rookie.

Frank said

I am thinking of both issues. You can't separate the two.

In the sense that you need to consider both, I agree. But the problems that arise are different.
Imagine an airframe designed to take, say, a 1000 hp Merlin. Increasing the power 'by magic' with improved fuel, better gas flow whatever makes you consider the stresse due to a greater 'pull' on the airframe. But putting in a substitute engine, say 50% heavier, means you have to consider the balance in the air, on the ground; whether the mountings are strong enough, a whole range of additional factors before you even start the engine. That's really what I meant. I can imagine the Cessna tipping on its nose on hitting a bump taxying, if it got that far

 

[joncarrfarrelly]

The Supermarine type 391 was a fair bit larger than the Spitfire or Spiteful.

Two images at the bottom here.

The Eagle 22 might be giving 2410hp at that time (when btw?) but that figure could be rapidly improved considering the engine size. Derby had a Merlin running at 2640hp in 1944. The Eagle being about 70% larger should be able to beat this easily with a bit of fiddling.

I'm familiar with the 391, but that aint' a Spitfire.

The power rating at altitude is for the Eagle 22 of the 1947-1949 time period...as mounted in the first Wyvern, the much bandied about number of 3,500hp is the take-off power rating at maximum boost.

Piston engine output drops as altitude increases.

The simple fact is that the development of the much simpler turbojet made all of the hyper-complex multi-piston beasts a technological dead end.

Jon