Stealth Pilot wrote:
On Fri, 15 May 2009 13:26:27 -0400, Orval Fairbairn
wrote:

In article ,
Stealth Pilot wrote:

(snip)
so one weight reduction option is to make it shorter, which leads to
looking again at the pobjoy geared radial made back in 1934. I've
always believed that a modern technology revisit to this design would
pay dividends. at 23inches diameter and delivering 90hp it has to be a
winner.
From what I have heard, the Pobjoy was NO joy to fly! Apparently it was
highly unreliable and would quit at the least desirable times.

The Pobjoy factory was destroyed during a WW-II bombing raid (perhaps by
disgruntled RAF pilots who had flown one?).

(snip)

I was talking with the Shuttleworth Trust guys about their Comper
Swift and its Pobjoy. evidently it has been made from a few different
models and is a nightmare for replacement parts. they have had it
embalmed for 3 years now. they usually rest aircraft for two years at
a time in rotation but the Pobjoy is problem enough that they didnt
take it out of preservation. It leaks oil like the best of british
engines evidently.
but the design of the pobjoy has aspects that are brilliant. picture
90 hp out of a little engine 22 inches in diameter.
it has one often overlooked claim to fame in that it was the first of
the high reving geared reduction engines.

I still maintain that this engine is worthy of a manufacturing revisit
and update for the homebuilder market.

does anyone know whether any of the drawings remain for any of the
pobjoy engines? I'd like to build one.

Short Brothers in Ireland evidently bought out Pobjoy when it went
toes up but I have not been able to find out whether any of the Pobjoy
factory drawings have survived.

Stealth Pilot.


A Comper Swift flew out of Coventry (UK) in the 60s-70s time frame.
It had the unexpected attribute that it could climb almost twice as fast
as a C150 - though its top speed was nothing to write home about.
It was called "Scarlet Angel". It was the plane that had flown home from
India. I later regretted not taking up the offer to buy it when the
opportunity came along.

Brian W