The Forum is administered separately from the rest of the website - please log in below to post
  New Posts New Posts RSS Feed - J.A.P. 45 hp engine 1909
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

J.A.P. 45 hp engine 1909

 Post Reply Post Reply Page  12>
Author
Errol Martyn View Drop Down
Senior Member
Senior Member


Joined: 17 Apr 2009
Location: New Zealand
Status: Offline
Points: 157
Post Options Post Options   Thanks (0) Thanks(0)   Quote Errol Martyn Quote  Post ReplyReply Direct Link To This Post Topic: J.A.P. 45 hp engine 1909
    Posted: 02 Jun 2010 at 03:16

I am trying to establish if J A Prestwich ever produced a 45 hp engine during 1909 (or possibly in 1910) that could be used for an aircraft. I am aware of a 35 hp model but not of a 45 hp one.

Any info, or direction to a source where such may be found, would be most welcome.

Errol

Back to Top
NickForder View Drop Down
Senior Member
Senior Member


Joined: 01 Jun 2009
Location: Bolton
Status: Offline
Points: 1369
Post Options Post Options   Thanks (0) Thanks(0)   Quote NickForder Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2010 at 08:03
Errol
Have you seen Jeff Clews' book on JAP ?
Though it is mostly about motorbikes, it does have a chapter on aircraft engines, the JAP-Harding monoplane and the brief JAP-Roe partnership.
I have a copy of the relevant chapter somewhere (the book was in the local library) and will try to dig it out.
Another possible source is Alec Lumsden's book on British piston engines.
Nick
Back to Top
Errol Martyn View Drop Down
Senior Member
Senior Member


Joined: 17 Apr 2009
Location: New Zealand
Status: Offline
Points: 157
Post Options Post Options   Thanks (0) Thanks(0)   Quote Errol Martyn Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2010 at 08:40
Nick,
 
Thanks kindly for the rapid response.
 
I've now had a look in Lumsden but nothing therein about a 45 hp engine, only the 9, 20 and 40 hp (and no mention of the 35 hp.)
 
I'm not familiar with the Clews book and would welcome any info it might contain, especially if it included photos of said engine (there is a photo in Lumsden - page 159 - of the 40 hp installed in the Martin-Handasyde No.3 but it shows only part of the engine and not from a good angle).
 
Errol
Back to Top
NickForder View Drop Down
Senior Member
Senior Member


Joined: 01 Jun 2009
Location: Bolton
Status: Offline
Points: 1369
Post Options Post Options   Thanks (0) Thanks(0)   Quote NickForder Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2010 at 08:45
Errol
Will do.
The other issue about early engines is that the ratings tended to be nominal. Hence the smaller Viale (fitted to an Avro D, the F and the Bristol Babe) is variously noted as a 35 h.p. and a 50 h.p. The larger Gnomes (Bleriot XI-2 etc) are noted as 70-80 h.p. Also, there is the RAC engine rating which has little to do with actual output.
Nick  
Back to Top
Paul R Hare View Drop Down
Senior Member
Senior Member


Joined: 10 May 2009
Location: United Kingdom
Status: Offline
Points: 282
Post Options Post Options   Thanks (0) Thanks(0)   Quote Paul R Hare Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2010 at 19:40
JAP made an air-cooled V8 which produced 38.4 hp under test.
This was variously refered to as either 35 or 40 hp ( depending upon whther you were buying or selling!).
There was no engine rated at 45hp.
Hope this helps.
Paul.
Back to Top
Errol Martyn View Drop Down
Senior Member
Senior Member


Joined: 17 Apr 2009
Location: New Zealand
Status: Offline
Points: 157
Post Options Post Options   Thanks (0) Thanks(0)   Quote Errol Martyn Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jun 2010 at 01:17

Paul,

Interestingly, I received in part this reply over on the Aerodrome:
 
"But J.A.P. also built a 1909/10 Water-cooled V8 that was rated at 45HP @ 1300rpm.
The bore was 90mm (3.54") and the stoke was 110mm (4.33"). It was a 340.88 cu. inch engine and weighed 303lbs.

Source: Aerosphere 1939. (The Same information is also detailed in The Airplane Engine Encyclopedia of 1921 -both volumes by Glenn D. Angle) "
 
Errol
 
Back to Top
Robert Mann View Drop Down
Newbie
Newbie


Joined: 29 Jun 2009
Location: Whangaparaoa NZ
Status: Offline
Points: 7
Post Options Post Options   Thanks (0) Thanks(0)   Quote Robert Mann Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2010 at 00:12
That's 20.8 litre swept volume. The weight claimed for that much metal, 303 lb, is implausibly tiny.   My 1953 110 bhp (SAE) Ford V8, only 1/7 the swept volume, weighs about 300 lb, probably a bit more.
     The implied specific power is a paltry 2.2 bhp/litre. JAP made some of the best motor-cycle engines of that period, bought in by a dozen mfrs including Royal Enfield; they were a highly respected mfr; if ever they made a 21-litre engine it would have produced many times more than 45 bhp.
     There is a possibility, allowed by logic, that the stated power was at rpm far short of peak power. But is that plausible?

     The stated figures are wrong, to some unclear extent. I could not regard this source as reliable.

RM
--
Back to Top
Paul R Hare View Drop Down
Senior Member
Senior Member


Joined: 10 May 2009
Location: United Kingdom
Status: Offline
Points: 282
Post Options Post Options   Thanks (0) Thanks(0)   Quote Paul R Hare Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2010 at 08:13
Robert,
 Your Ford V8 would have been water cooled and the air-cooled JAP could thus have been lighter for its swept volume, especially as it was intended for aviation, where power is paramount rather than for motoring where simplicity and longevity rule.
Also aero engines of the period were designed to run at very rotational speeds in order to ensure propeller  efficiency. 1300 rev/min in the case of the JAP, which would have been little more than a fast tick-over, for a car  Even a side valve like your ford would rev up to maybe 4500 at which speed the JAP, had it been so designed could have given far far more power than 45 hp.
Incidently the  Renault V8, built a year or so later, had a swept volume of around 25 lites,, weighed just over 400 pounds and was rated at 70 hp. The RAF1a, which was developed from the Renault and was dimensionally very similar, was rated first at 90hp and then, with an increased compression ratio, at 105 hp.
Paul.
 
Back to Top
NickForder View Drop Down
Senior Member
Senior Member


Joined: 01 Jun 2009
Location: Bolton
Status: Offline
Points: 1369
Post Options Post Options   Thanks (0) Thanks(0)   Quote NickForder Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jun 2010 at 13:12
Errol
Clews states that by 1910 the following JAP engines were available for aviation applications :
V4 85 mm x 110 mm side valve air-cooled
V8 85 mm x 95 mm ohc, 35 h.p. air-cooled, 4.4 litre
V8 90 mm x 110 mm ohv, 50 h.p. water cooled, 190 lbs. (Copper water jacket was made by coating cylinders with wax and then electro-depositing copper).
V8 85 mm x 110 mm, side valve, 40 h.p. air-cooled
 
All had ported cylinder barrels and upward pointing exhaust pipes.
 
Clews notes the use of a JAP in the Martin biplane (made by Martin & Handasyde); to power the first mail carrying aircraft in Australia (!); for an aircraft made by Sir Malcolm Campbell; the JAP-Harding monoplane (in the Science Museum); a Willows dirigible; as well as in early Roe aircraft.
Nick 
Back to Top
Robert Mann View Drop Down
Newbie
Newbie


Joined: 29 Jun 2009
Location: Whangaparaoa NZ
Status: Offline
Points: 7
Post Options Post Options   Thanks (0) Thanks(0)   Quote Robert Mann Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jun 2010 at 21:32
The dimensions stated for the 8-cyl JAP (90 x 110mm) give a swept vol per cyl of 700cc i.e engine swept vol only 5.6 litre. At that rate, sp power is 45/5.6 = 8 bhp/litre, an order of magnitude lower than commonly achieved much more recently. But as Paul points out, the rpm at which these early aero engines were run was very low; and that could not increase much until addition of (weighty) gearboxes to allow engines to rev faster while keeping prop tips sub-sonic.

There is also some vagueness about that blighted term 'horsepower'. The dreaded, deeply irrational RAC rating "horsepower", basis of the UK road tax, doomed Pommie motors to undersquare cylinders i.e high piston speeds (at any given rpm). It may be difficult to find out what J. A. Prestwich meant exactly by his "45 hp". It wouldn't surprise me if he under-stated his hp figures.

A small puzzle has now emerged: how could that distinguished engine-producer get (as stated in the table Nick gave us) more power from a side-valve than from the fabulous overhead cam? It's difficult to see why JAP would bother with OHC at that stage. Their 350cc & 500cc side-valves powered a dozen brands of motorcycle shortly before the Great War (including the best motorbike of that time, the Maori); the main justification for the complexity of OHC is to decrease reciprocating mass in the valve train, which (as shown by Amédée Gordini and by Burt 'The World's Fastest Indian and plus you get the world's fastest Velocette' Munro of my country, isn't needed below 7500 rpm; so for the JAP V8, revving at what today would rank as little more than a fast idle, OHC would seem superfluous.
Back to Top
 Post Reply Post Reply Page  12>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 10.03
Copyright ©2001-2011 Web Wiz Ltd.
Create your own user feedback survey
find us on Facebook Follow us on TwitterGrab our news feed