Piston Perfection

[Glenn Gilbertson]

Have had a play with profile photographs to measure a Fairey P.24 Monarch installation - XP-47 as first effort:

[jcf]

Hi Glenn,
nice first chop.

Something to keep in mind is that the P-47's deep belly was largely the result of the turbo-supercharger being installed in the rear fuselage, the exhaust gas and cooling air ducting occupied the bulk of the belly space.


A P.24 powered aircraft could be far more svelte, and being liquid-cooled would require a radiator. Possibly a Mustang-like belly radiator or maybe wing leading edge radiators.

One other note, the XP-47 and XP-47A designations referred to an Allison V-1710 powered 'light' fighter, the Thunderbolt, more or less as we know it, came about with the XP-47B designation.


Cheers, Jon

[elmayerle]

Would a P.24-powered P-47 look that different from the IV2220-powered XP-47H?  I'd certainly think the nose contours of the XP-47H could serve as a starting point.

[jcf]

Would a P.24-powered P-47 look that different from the IV2220-powered XP-47H?  I'd certainly think the nose contours of the XP-47H could serve as a starting point.

I suppose its possible, but the XP-47H always looked kluged together to my eye, I wonder if a 'production' version would have had a neater look and better radiator installation. The P.24 with its integral supercharger design was a much smaller package than the lumpin' great Chrysler V-16 with it's air-to-air after-cooled supercharger and water-to-air inter-cooled turbo-supercharger. Could ya guys have made it a little more complex? :dum:  :dum:



Jon  

[Glenn Gilbertson]

Thanks for the comments, Jon. Revised versions of the XP-47monarch, using the Battle test-bed radiator as a guide - XP-47P?

[elmayerle]

Would a P.24-powered P-47 look that different from the IV2220-powered XP-47H?  I'd certainly think the nose contours of the XP-47H could serve as a starting point.

I suppose its possible, but the XP-47H always looked kluged together to my eye, I wonder if a 'production' version would have had a neater look and better radiator installation. The P.24 with its integral supercharger design was a much smaller package than the lumpin' great Chrysler V-16 with it's air-to-air after-cooled supercharger and water-to-air inter-cooled turbo-supercharger. Could ya guys have made it a little more complex? :dum:  :dum:



Jon

For a production radiator installation, perhaps something similar in appearance to that of the Typhoon and Tempest, but set back more from the plane of the propeller(s)?    It might be fun to mod a XP-47H kit that way to get an operational version.  I suspect, though, that a bit larger radiator might be needed.

Glenn, I like your alternatives, too, though I suspect that a bit of boundary layer diversion will be needed for the radiator inlet.

Too, does anyone know if the XP-47H retained the belly-mounted supercharger?  If it did, then that would certainly affect the installation requirements and design.

[elmayerle]

Thanks for the comments, Jon. Revised versions of the XP-47monarch, using the Battle test-bed radiator as a guide - XP-47P?

Gorgeous!!  Now we add a bubble canopy and the wings of the P-47N as I understand that those actually allow a bit higher top speed than the regular P-47 wing.

[jcf]

Hi Evan,
the IV-2220 installation used an engine-mounted after-cooled mechanical supercharger and a water-to-air inter-cooled turbo-supercharger mounted in the aft fuselage, in much the same location as a standard P-47.


Rear of engine showing supercharger, aftercooler and accessories.

Jon

[jcf]

Thanks for the comments, Jon. Revised versions of the XP-47monarch, using the Battle test-bed radiator as a guide - XP-47P?

Lookin' good Glenn, but, one quibble... I think the engine is mounted much further forward than necessary.
Remember its not really that 'big' of an engine:
P-24
length: 86.25"
width: 43.0"
height: 52.5"

P&W R-2800-73 (P-47N)
length: 78.394"
diameter: 52.8"
weight: 2,350 lbs


Keeping the firewall in the same location on the airframe (in the cutaway the firewall is in line with the forward wing spar), the P.24 installation would, most likely, be only 10 to 12 inches longer. The weight of the P.24 is definitely greater than that of the R-2800, by how much is anybodies guess. The Fairey H-16S Prince 3 weighed 2,180 lbs and used cylinders of exactly the same bore as the P-24, so for an engine half again as large, the weight would probably be in the area of 3,000 lbs plus. Couple that with removing the turbo-supercharger assembly in the aft fuselage and you'd probably even want the engine installation moved aft to compensate, the new radiator installation would add some weight towards the rear.

Cheers, Jon

[elmayerle]

I agree with Jon, you almost have to have the radiator in the rear to maintain decent weight and balance characteristics.  One thought, though it'd need some careful fuselage redesign would be a radiator installation similar to that of the P-51, esp. the Merlin-powered variants, that managed to have a negative drag effect.  

I think you could work this into the P-47 airframe, but it'd take some careful lines work and radiator design, working together.

[jcf]

A big Meredith effect radiator installation in an armoured tub.

Gotta keep that ground attack capability.  :ar:  :ar:

Jon

[Glenn Gilbertson]

Interesting thoughts on the P-47 - will have to think further!
Has anyone else seen the current "Fly Past" magazine (December 2007 no. 317)?
It has a picture of a model of a 1944 Scottish Aviation project - a twin hulled, six (or twelve coupled) engined, 160 seater transatlantic airliner. Landplane or flying boat versions were proposed. What a beast - does anyone know any more?

[elmayerle]

A big Meredith effect radiator installation in an armoured tub.

Gotta keep that ground attack capability.

That works for me.  The neat trick would be, if you still retained the turbocharger in addition to the supercharged stages on the engine, set up the the turbocharger exhaust to create an ejector pump effect downstream of the radiator, this would help pull air through at very low speeds.

[Tojo633]

Glenn

Ask TSR2 Joe he knows a lot about Prestwick, Scottish Airlines etc etc etc so he may be able to shed some light on it, nice model though pity its in the case would look better hanging. Having looked at the cockpit area in the pic and the style of the cockpit I wonder if TSR2 Joe had built it for them? Will ask when I speak to him on the trombone tonight.

Spoke to his nibs and he did some restoration work on the model in question.

Cheers
Sandy

[jcf]

A page that may provide more inspiration:

Experimental engines at the Pratt & Whitney Museum
http://www.enginehistory.org/P&W/p&w_museum_(2).htm

Jon