But, but he doesn't need time for drawings, and I have to say the quality of his work is outstandingOriginally Posted by Frits Overmars
Hardcore Biker
But, but he doesn't need time for drawings, and I have to say the quality of his work is outstanding
Muddler/Dabbler.
Going back a little, that disc valve setup was used experimentally on a NSU Rennmax 250, but apparently unsuccessfully.But, but he doesn't need time for drawings, and I have to say the quality of his work is outstanding
The Ju88 normally used a V12 liquid cooled engine all wrapped in a neat cowl which made it look like an aircooled radial.
The opposed piston Jumo engine was employed successfully in torpedo boats - it was also developed further (by Napier in Britain who had acquired the right to build them under licence in the thirties) into the Napier Deltic Locomotive engine - these were very successful engines used for many years.
Best check it out - even I can sometimes be wrong!
has made a bo-bo in his nappies
Going back a little, that disc valve setup was used experimentally on a NSU Rennmax 250, but apparently unsuccessfully.
The Ju88 normally used a V12 liquid cooled engine all wrapped in a neat cowl which made it look like an aircooled radial.
The opposed piston Jumo engine was employed successfully in torpedo boats - it was also developed further (by Napier in Britain who had acquired the right to build them under licence in the thirties) into the Napier Deltic Locomotive engine - these were very successful engines used for many years.
Best check it out - even I can sometimes be wrong!
Yeah W-D, & your post quoted above needs a bit of correction..
As previously noted in this thread, the in-service Ju 88 flew with Jumo V12's or BMW radials in a German power-egg equivalent to the British Merlin/Hercules set-up used in Lancasters & Beafighters,.
The Jumo V12 was also to be found doing duty as an alternative to the BMW radial in the later Ju 188, & FW 190 machines, which also used the
annular/drum-type front mounted radiator, but didn't really look too radial like, being longer & with a tell-tale inline set of ejector exhausts..
The opposed piston CI 2T was used in the Ju 86, & made some very high ( for the day) altitude photo-recon/bombing raids on Blighty..
The Napier Deltic was a typically innovative Napier mill that successfully mated 3 sets of the Jumo OP design en-bloc, running one crankshaft
in reverse rotation for timimng purposes.
The Deltic name came from the triangular arrangement resembling the Greek letter of the same name, & the mill was so effective that even
the USN used them for fast patrol boat duties in Viet-Nam, during the war there, The Deltic was too heavy to fly, of course, but Napier had the
Nomad CI 2T for that application, which was sadly cruelled by the advent of the gas-turbine for aero-mills, ( & like the Deltic, did not feature SV's..)
Hardcore Biker
Sorry sorry, I cluttered up the thread.
Here's another little oddball engine, it was patented by Robert Reynolds in 1909:
http://www.douglas-self.com/MUSEUM/P...ynolds%202.jpg
It uses a flat rotary disc valve in the head!
http://www.google.co.uk/patents/US924382
Muddler/Dabbler.
As I said earlier, NSU experimented with a similar design (post war) but I can't find anything about it on the net. However I have a book somewhere with some details and I will scan the pic when I find it.
BTW. we were discussing four stroke disc inlet and exhaust valves (in the cylinder head) here - not to be confused with two stroke disc inlet valves in the crankcase, a totally different scenario.
Someone mentioned earlier that Scott motorcycles used disc inlet valves in the crankcase of their two stroke twins way back in the early part of the 20th century, but I believe they were actually oscillating valves driven off the conrod (please don't quote me on this though - I'm not a fanatical "Googler")
Hardcore Biker
I look forward to seeing the NSU pics.As I said earlier, NSU experimented with a similar design (post war) but I can't find anything about it on the net. However I have a book somewhere with some details and I will scan the pic when I find it.
BTW. we were discussing four stroke disc inlet and exhaust valves (in the cylinder head) here - not to be confused with two stroke disc inlet valves in the crankcase, a totally different scenario.
Someone mentioned earlier that Scott motorcycles used disc inlet valves in the crankcase of their two stroke twins way back in the early part of the 20th century, but I believe they were actually oscillating valves driven off the conrod (please don't quote me on this though - I'm not a fanatical "Googler")
Some Scotts had a rotary cylindrical type inlet valve.
At first they used a chain drive to the valve. Then they switched to a gear drive. Finally they switched to a simple link from the con-rod, and the valve oscillated. That was more than 100 years ago!
I think the Scotts were way ahead of their time, watercooled twins, overhung cranks, low COG, first kick start on a motorbike.
Regarding rotary valves in the head, quite a few have tried these, without much success.
There's an exception, a Kiwi, Ralph Watson, who converted a BSA V twin in his sports car, to rotary valves.
An account of how he did it can be found here:
http://ralphwatson.scienceontheweb.net/rotary.html
I wonder is Ralph related to Neil.
Muddler/Dabbler.
Yes that's the valve arrangement I was thinking of! - Scott was way ahead with his thinking, but I wouldn't be so sure of overhung cranks! we see this arrangement often in weedeaters etc.(strimmers to you) and model aircraft engines etc. but a bit impractical on motorcycles (two shafts usually required). I've also seen the results of the conrod slipping off!
As for four strokes (or ohv two strokes) I don't think that the sliding action of the rotary valves takes too kindly to the lack of lubrication or the heat!
Yes, I know that Aspin, Cross etc. nearly got there, but not quite!
We have a Kiwi axial engine here in Auckland (the Duke engine which appears to be a highly developed design loosely based on the one used by the Bristol Tramways of the thirties) and is working very well. It uses sliding contact exhaust port valves and has gradually progressed to an advanced stage.
How easily it will manage to break into the automotive/aviation market etc. remains to be seen!
UPDATE - And no, I doubt if Neil is related to Ralph Watson, Neil is the only one of his kind!
However that was a very interesting article on the rotary valve car, Ralph obviously was (or is?) a very dedicated and methodical guy and didn't give up like many others did!
BTW, in that article, if you scroll down to a few paragraphs before the first illustration, the NSU overhead disc valve got a mention (no illustration though) - that, is what I am still trying to locate!
Muddler/Dabbler.
My uncle had a Field Marshall tractor and I did see him start it once with a cartridge, but I'm pretty sure that the cartridge didn't contain any pellets etc! - and if I was using it, I'd have made damn sure that it was at least 40deg past TDC before trying it - starting was instantaneous!!
Mostly the starting was done manually with 2 guys swinging the huge flywheel up to speed and flicking off the decompressor - what a bugger when it failed to start on a cold morning!
Low personal B.M.E.P.
Pretty sure Ralph's dead now. He kept the BSA car pretty well to the end of his life. He brought it South to an early Classic car race meeting and i was privileged to have a short conversation with him. He's much better known for the Lycoming special of course but the BSA suited him in his old age as he was in no hurry...One of many Kiwi specials builders who gained knowledge serving in the air force in WW2.
Muddler/Dabbler.
Why do all these Kiwis get forgotten? - just a tad too modest I guess, there is the odd exceptions of course, like the devious Kiwi gentleman who conned the Aussies as we discussed a while ago!
BTW, here is the picture of the Disc Valve NSU engine I was talking about - apparently the guy behind it was Froede and it wasn't on a 250cc Rennmax as I stated before, it was an experimental 125.
.
has made a bo-bo in his nappies
Yeah, W-D, the Coffman ( & there's an apropos name) cartridge starter was common on big aero-mills such as the Napier Sabre..
Some may recall the plume of pryotechics smoke that blew from the RNZAF Vampires turbo-jet on start-up using this device..
& of course the good ol' Coffman protocol was included as a suspense/dramatic sequence - in the original 'Flight of the Phoenix' movie..
I am a bit surprised that no red-blooded Kiwi old-school biker/engineer hasn't developed a Coffman starter for his Norton Commando,
but it'd likely be unlawful for downunder public use, - or to sell to the H-D hard men for use in 'Merica, as an extra tough 'n' loud burly biker turn on gimmick..
The Coffman system was light, which does make it attractive, albeit perhaps a bit fraught if mishandled, being flaming pyrotechical..
Hardcore Biker
Sorry to say he died in 2006.
Without doubt he was a very talented man,
More information on Ralph, and his many other projects can be found here:
http://ralphwatson.scienceontheweb.net/
Bogeyman
Coffman starter is nothing like the cartridge system on a Field Marshall.
There was once a couple of large Ruston Bucyrus draglines working the Clutha river, (memory says RB72s) and I think they were cartridge start too. There was a picture of my mother's Mini parked in one of the buckets in the Southland Times of the day. There's some formidable eels in that river I can tell you.
Go soothingly on the grease mud, as there lurks the skid demon
has made a bo-bo in his nappies
Yeah, it is..
The use of a compact lightweight expanding gas-thrust unit to boot the mill in the guts to run - is fundamentally identical..
Of course, no expensive high-quality aero-mill is gonna have the filthy pyrotechnical residues pumped straight through it,
so yeah, they have a mechanical-starter transfer stage, unlike the rusticated agricultural equipment, but in essence - its the same deal..
Low personal B.M.E.P.
Talented indeed. I note several mentions of Hec Green - he, Jack Brewer and my old man were good friends - and all AMIMechE qualified engineers. All had input into Hec's series of RA specials. A lot of it was designed on our kitchen table - with an interested kid watching...
Amusing also to see the casual mention of Rolls Merlin engine parts - often timing gears - used where appropriate. At one point a dealer in ChCh would sell you a crated merlin for about five pounds. The final twin cam RA Special motors used Merlin timing gears in the cam drive.
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