Poppets, sleeves & other stuff
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Poppets, sleeves & other stuff
Justifiably killed off by jets in their power sector, I've still got a fair nostalgia for the big ol' piston aero engines mostly from the beginning to middle of the last century
While most were poppet valve designs, that would easily be recognised today by any budding student, some of the more curious were the sleeve valve designs typified by the hot rod Sabre and the long haul Centaurus, originating from the automotive patents of earlier
But regardless of poppets & sleeves :
Vs, Xs, radials, inlines, multibanks ...... two and four stroke ...... etc, etc ...... most of it flew in some form or other ..... so what is your peccadillo ?
While most were poppet valve designs, that would easily be recognised today by any budding student, some of the more curious were the sleeve valve designs typified by the hot rod Sabre and the long haul Centaurus, originating from the automotive patents of earlier
But regardless of poppets & sleeves :
Vs, Xs, radials, inlines, multibanks ...... two and four stroke ...... etc, etc ...... most of it flew in some form or other ..... so what is your peccadillo ?
Re: Poppets, sleeves & other stuff
I always liked the Ranger, inline 6 cylinder. I believe they were SOHC engines.
They were used in Sprint Cars, for a while, in the early '60's, maybe late '50's, too. I've only seen pictures of the exterior but, would love to know what they look like on the inside.
They were used in Sprint Cars, for a while, in the early '60's, maybe late '50's, too. I've only seen pictures of the exterior but, would love to know what they look like on the inside.
Re: Poppets, sleeves & other stuff
I don't have the citation at hand, but one of the more bizarre prototypes was a giant horizontal two-cylinder designed to mount in the fuselage and power the props via links. The idea came about because the exposed radials were getting damaged by gunfire and the central mounted engine could be protected by armor. It obviously wouldn't have worked, but the guvmint was throwing money at anyone who wanted to build anything, cost+.The Napier Sabre was a British H-24-cylinder, liquid-cooled, sleeve valve, piston aero engine, designed by Major Frank Halford and built by D. Napier & Son during World War II. The engine evolved to become one of the most powerful inline piston aircraft engines in the world, developing from 2,200 hp (1,600 kW) in its earlier versions to 3,500 hp (2,600 kW) in late-model prototypes.
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
Studebaker-Packard V8 Limited
Obsolete Engineering
Re: Poppets, sleeves & other stuff
The Brits loved sleeve valve engines...
We always hear all the aero engines had hemi combusting chamber. True for air cooled radials but the main liquid cooled V12's used by the US, Brits and Germans did not. The Allison had a 4 valve penthouse, Merlin a 4 valve bath tub type and the Dailmer Benz had a shallow chamber with inline valves I believe... Don' know if this was for best efficiency or design limitations..
We always hear all the aero engines had hemi combusting chamber. True for air cooled radials but the main liquid cooled V12's used by the US, Brits and Germans did not. The Allison had a 4 valve penthouse, Merlin a 4 valve bath tub type and the Dailmer Benz had a shallow chamber with inline valves I believe... Don' know if this was for best efficiency or design limitations..
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
Re: Poppets, sleeves & other stuff
Yes,very complex with amazing array of gears to drive it allexhaustgases wrote: ↑Tue Jul 21, 2020 6:43 pm Sleeve valves as used in the old Aircraft engines, tedious manufacturing, and lubricating of the reciprocating cylinder with in a cylinder not easy.
The US preferred more simple engines with less parts comprised of sub assemblies more easily assembled by semi skilled workers just like the auto engines. And air cooled radials that could take a pounding and keep running.
mechanism.
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
Re: Poppets, sleeves & other stuff
A WW 2 vet once told me: "If you wanted to impress your girl friend have your picture taken by a P-51; if you want to get back home fly a P-47" (water cooled vs. radial)
Re: Poppets, sleeves & other stuff
If your interest in valve mechanisms gets overwhelming get a copy of " Valve mechanisms for high speed engines"by P Smith. Anything that can be used to fill and empty a cylinder is in this book,,, there is also mention of "Vasco-jet" steel for valve springs being one of the big game changers for reliability.
If Your interest is more leaning to aero engine design,you can't go past "Development of aircraft engines and aviation fuels" by Schlaifer and Heron, both are great period reads.
Cheers.
If Your interest is more leaning to aero engine design,you can't go past "Development of aircraft engines and aviation fuels" by Schlaifer and Heron, both are great period reads.
Cheers.
Re: Poppets, sleeves & other stuff
It's not unfair to say the early development of the PV12 Merlin was beset with problems, to the extent it was severely in danger of disrupting the introduction of several strategic aircraft, the Hurricane and Sptifire not least
The early 'Ramp Head' design just couldn't be made to work, and reverted to the 'bath tub' Kestrel design
Looking at the RH design, which 'looked' right and gave a much 'cleaner' aerodynamic installation, 'end gas detonation' immediately shouts out as the possible root cause of at least some of the problems
It's hard to see how RR engineers didn't immediately see it, I guess it's maybe easier with 20/20 hindsight ....... most successful engines had softer combustion chambers that negated this
The Benzs were mostly decent engines, but with their own quirks whilst the Allisons were about the most reliable of the bunch, but not developed to suit high altitude 'European' combat, on the whole
The Packard Merlins weren't bad either
Of course on of the first 'modern' aero engine design was the Curtiss D12, such that several companies, RR included, used it subsequently as 'inspiration' for future designs ...... it had it's own limitations but helped point the way forward
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Re: Poppets, sleeves & other stuff
RR was a large manufacturer with extensive experience in liquid cooled aircraft engines..And it was vitual to the UK to find solutions to the problems..
Allison was a much smaller company working on their first liquid cooled engine..General Motors who owned Allison seemed more interest in making money from war contracts than helping to devolop a first class engine..And unlike the Brits, the US military ran combat aircraft devolop . They constantly pushed for a turbo on the Allison despite troublesome boost controls and detonation caused problems..The Brits and Germans has much better automatic boost controls..
Allison was a much smaller company working on their first liquid cooled engine..General Motors who owned Allison seemed more interest in making money from war contracts than helping to devolop a first class engine..And unlike the Brits, the US military ran combat aircraft devolop . They constantly pushed for a turbo on the Allison despite troublesome boost controls and detonation caused problems..The Brits and Germans has much better automatic boost controls..
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
Re: Poppets, sleeves & other stuff
The US military/industrial complex continually made decisions as much on what would be profitable post-war as what would be best for the war effort. They correctly foresaw postwar passenger travel as a coming thing, so the US concentrated building heavy bombers with radial engines; these having immediate transfer to civilian application. They left the Brits to take the dead-end load of liquid cooled V-type engines and prop fighters.
GM declined to spend their resources on refining the Allison, correctly assuming it to be of no use post-war.
The Studebaker fans still resent GM requiring all GM-produced military vehicles to be used by US forces. The Studebaker-produced trucks could only be sent overseas to be used by allied forces, mainly the Russians. GM advertised continually throughout the war as to how their production kept the US forces moving.
GM declined to spend their resources on refining the Allison, correctly assuming it to be of no use post-war.
The Studebaker fans still resent GM requiring all GM-produced military vehicles to be used by US forces. The Studebaker-produced trucks could only be sent overseas to be used by allied forces, mainly the Russians. GM advertised continually throughout the war as to how their production kept the US forces moving.
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
Studebaker-Packard V8 Limited
Obsolete Engineering
Re: Poppets, sleeves & other stuff
From a maintenance point of view using vehicles made by the same manufacturer with the same mechanical parts is a good idea.
I have seen WW2 Sudebaker 10 wheel trucks but never looked under the hood, what engine? Far as I know all the GM 10 wheel 2-1/2 tons used a GMC 270 6. The Chevys were all 6 wheelers using the 216 or 235 version of the same engine....I can't recall who made the driveline parts...
I have seen WW2 Sudebaker 10 wheel trucks but never looked under the hood, what engine? Far as I know all the GM 10 wheel 2-1/2 tons used a GMC 270 6. The Chevys were all 6 wheelers using the 216 or 235 version of the same engine....I can't recall who made the driveline parts...
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
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Re: Poppets, sleeves & other stuff
a few went to Bonneville as well.frnkeore wrote: ↑Tue Jul 21, 2020 12:44 pm I always liked the Ranger, inline 6 cylinder. I believe they were SOHC engines.
They were used in Sprint Cars, for a while, in the early '60's, maybe late '50's, too. I've only seen pictures of the exterior but, would love to know what they look like on the inside.
Re: Poppets, sleeves & other stuff
After I posted about the Ranger, I did a search (had never done that before. I hadn't even thought of the Ranger until this subject came up), there is quite a bit of info on it actually.
It was first used in 1937 in trainers so, it was almost 20 years old, before guys started using it in race cars. Even today, it could still hold it's own with our push rod V8's. It's a hemi chambered SOHC engine, 440 CI but, with a 5.5" stroke. Aluminum head, screwed into a cast iron cylinder, using a interference fit. No head gasket problems and somewhat similar to the Offy. It was also, very light @ 365 lb. With a turbo and some modern upgrades, I think it could make 900 HP.
It was first used in 1937 in trainers so, it was almost 20 years old, before guys started using it in race cars. Even today, it could still hold it's own with our push rod V8's. It's a hemi chambered SOHC engine, 440 CI but, with a 5.5" stroke. Aluminum head, screwed into a cast iron cylinder, using a interference fit. No head gasket problems and somewhat similar to the Offy. It was also, very light @ 365 lb. With a turbo and some modern upgrades, I think it could make 900 HP.
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Re: Poppets, sleeves & other stuff
I went looking for a pic to refresh my memory, in the early fifties, Jot Horne and and Norm Taylor ran one in a '27 T roadster on '32 rails, had a crank driven 6-71 with four strombergs on a plenum mounted to the inlet side of the 6-71. Unfortunately the pic I have is too big to fit my scanner. My feeling is, there was at least one more that ran the salt, in a Model A Roadster, I will see if I can confirm that.frnkeore wrote: ↑Fri Jul 24, 2020 12:40 pm After I posted about the Ranger, I did a search (had never done that before. I hadn't even thought of the Ranger until this subject came up), there is quite a bit of info on it actually.
It was first used in 1937 in trainers so, it was almost 20 years old, before guys started using it in race cars. Even today, it could still hold it's own with our push rod V8's. It's a hemi chambered SOHC engine, 440 CI but, with a 5.5" stroke. Aluminum head, screwed into a cast iron cylinder, using a interference fit. No head gasket problems and somewhat similar to the Offy. It was also, very light @ 365 lb. With a turbo and some modern upgrades, I think it could make 900 HP.
Re: Poppets, sleeves & other stuff
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire