Percival P.35 to P.37 Bomber/Transport Projects

[Tophe]

http://forum.keypublishing.co.uk/showthread.php?p=1311473
you can find an unidentified Burnelli/Clyde 4-engined bomber model at POST #9. Any idea about its identity?

I add the picture, for a direct view of this twin-boom project:

 

[lark]

I think I solved the riddle of the 4 engined mystery bomber
posted in reply 14.

After a lot of searching and some correspondence I came to the conclusion that
it is the Percival P.37 heavy bomber of 1943.

The P.37 is a bomber development of the P.35 four engined freighter project following
the principles developed by Burnelli and designed by A.A.Bage ,chief designer of Percival Ltd.

The P.36 was a 6-engined variant of the P.35.

Based on information I found in the Aeroplane February 1944, the Aeroplane Spotter Feb.7 1948
and a description I received via Boxkite (thanks Thomas) I came to the above conclusion.
Exept for the the low drag dorsal turret on the bomber , the P.35 freighter is almost a look alike.
Same engines ,double main wheels etc...

After confirmaton by a chief moderator , perhaps this thread must be split..

 

[Jemiba]

I think, you're absolutely right, congratulations Paul !
It's in a line with the P.36, as we have it here http://www.secretprojects.co.uk/forum/index.php/topic,1523.msg12873.html#msg12873
and with the information in the designations section.
The turret looks like the Vickers S turret, tested with the Wellington.

 

[Antonio]

Excellent, lark

 

[hesham]

Nice find my dear Lark.

 

[lark]

I'll send Jemiba and Pometablava some additional info to confirm
and eventual extend my #18 post.

 

[Stargazer]

Split from the Clyde Clipper thread after identification by lark

A sound decision, thanks Jemiba.

 

[JFC Fuller]

After a lot of searching and some correspondence I came to the conclusion that it is the Percival P.37 heavy bomber of 1943.

The aircraft pictured in the first post of this thread looks like it was designed to B.1/39 (the turret is clearly a quad 20mm one as specified by B.1/39 and the nacelles look like they are for the Hercules, a common engine choice for this competition). However, the down-select for this competition occurred in June/July 1939 and the entire project (including turrets) was abandoned in June 1940. For me, it is highly unlikely (if not impossible) that this aircraft design dates to 1943, much more likely it dates to 1939.

 

[Cy-27]

From the source below:

P.37 (Percival Type Ag)
This was a bomber version of the Percival P.35 proposed in 1943, for use as a heavy bomber for the RAF. Like the P.35 it was powered by four 2,500 hp Bristol Centaurus engines and the speed would have been quite slow at 169 mph. It was designed to the same overall dimensions as the P.35 with a wingspan of 140 ft and 103 ft overall length. Like the P.35 this version was not built.

Source:
On The Wings of a Gull by David W. Gearing (Air Britain) ISBN 9780851304489

 

[Schneiderman]

The 18th Feb 1944 article in The Aeroplane includes a surprising amount of dimension data for the P.36 and photos of a model of the P.35. With those it is possible to make a fairly accurate 3-view of both. Here is the P.36 (edit - 3-view updated)

 

[Schneiderman]

This is the P35, the earlier design. It was planned to be powered by 4 x 3000hp hypothetical engines. When it became apparent that these would be unlikely to be developed they swapped to 6 x 2500hp engines for the P36, Bristol Centaurus. The airframe was basically the same except that the wings span was increased from 140ft to 158ft.

 

[lark]

Excellent work ! Thanks.

 

[airman]

This is the P35, the earlier design. It was planned to be powered by 4 x 3000hp hypothetical engines. When it became apparent that these would be unlikely to be developed they swapped to 6 x 2500hp engines for the P36, Bristol Centaurus. The airframe was basically the same except that the wings span was increased from 140ft to 168ft.
View attachment 681036

the 4 x 3000hp hypothetical engines could be have been american engines.

 

[Schneiderman]

the 4 x 3000hp hypothetical engines could be have been american engines.

They could indeed, but Percival clearly thought they were unlikely to obtain any, wherever they were to come from, and concentrated their efforts on the 6-engine P36

 

[Schneiderman]

OK, just in case anyone asks I did intend to make a drawing of the P37 bomber but there are problems that prevent that. The model shown in #1 is definitely not a direct military version of the P35 as there are a large number of differences in the layout and detail. I would still agree that it is most likely a model of the P37 but cannot be sure whether the model is inaccurate or whether it was a new design.

 

[lark]

P37 .... bomber version of the P35. source : " On the Wings of the Gull " - Air Britain.

P37 ...... third in a series of Burnelli type designs source : "Percival Aircraft " Arthur Ord-Hume -Stenlake.

There are indeed a few differences between the model in post 1 and the P.35 ( mainly in the tailplane and nose section )

 

[Schneiderman]

P37 .... bomber version of the P35. source : " On the Wings of the Gull " - Air Britain.

P37 ...... third in a series of Burnelli type designs source : "Percival Aircraft " Arthur Ord-Hume -Stenlake.

There are indeed a few differences between the model in post 1 and the P.35 ( mainly in the tailplane and nose section )

Yes, I was aware of those references.
The differences are actually more extensive than you mention. The P35 and P36 had three parts to the wing; the lifting fuselage, the outer wing, and a transition section. The article in Aeroplane gives the chord and span for each, which enables the 3-view to be made. The P37 has just the fuselage and wing, no transition, with the booms aligned with the inner engines, they are inboard on the P35 and P36. The model suggests that the fuselage section is of lesser chord than for the freighters, which is logical as a bomber does not require that amount of internal space. Then with a reduced chord it is probably not as deep, the model appears to confirm this. Also, with a shorter fuselage the total length of the aircraft is probably less too. The main wing looks as if it has a greater inboard chord and greater taper than on the P35. Then there is the larger cockpit and nose section and the substitution of double tail wheels for the freighter's nose wheel. All in all I am doubtful that the aircraft represented by the model can be described as a militarised P35, there are too many changes for that.

 

[hesham]

From Aeroplane monthly 1983.

 

[hesham]

From Aeroplane monthly 1983.

From this book.

 

[hesham]

In replies # 18 & 19,may that was P.37 ?.

 

[Short Arry]

This is the P35, the earlier design. It was planned to be powered by 4 x 3000hp hypothetical engines. When it became apparent that these would be unlikely to be developed they swapped to 6 x 2500hp engines for the P36, Bristol Centaurus. The airframe was basically the same except that the wings span was increased from 140ft to 168ft.
View attachment 681036

the 4 x 3000hp hypothetical engines could be have been american engines.

Or a Bristol development. I vaguely recall reading about a proposed Bristol 28 cylinder radial that was basically a "Double Hercules", possibly under the name Orion, but not sure about that bit.

 

[hesham]

Or a Bristol development. I vaguely recall reading about a proposed Bristol 28 cylinder radial that was basically a "Double Hercules", possibly under the name Orion, but not sure about that bit.

Welcome aboard Short Arry,please have a look.

 

[Nik]

I notice there was no mention at all of Burnelli...

 

[VictorXL188]

I noticed in the Aeroplane Monthly article, that Hesham posted, that the caption referred to six engines (P36) when the model pics clearly show only four engines(P35)!