Whatever happened to sleeve valve engines?
The Hawker Tempest was the fastest piston powered airplane ever made, it had a sleeve valve engine. It was made obsolete, by the Me 262 and other jet engined fighters, But it's engine was the ultimate piston aircraft engine. Then piston engines became something for inexpensive planes, but why has the sleeve valve not undergone further development as a sports car engine?
The main problem was the oil consumption, since a very tight seal required close tolerances that in turn called for very precise lubrication.
As Wikipedia states (see link) if one wants to do away with poppet valves, and is willing to accept a very wide lubricated area, one might as well go all the way and go with a Wankel rotary engine which entirely eliminates the need for valve and thus timing gearing.
Note that military engines do not have to be certified the way civilian aero engine need be, this in turn makes the process of introducing any change in an engine design extraordinarily expensive, hence general aviation piston engines are rather crude (but proven) design.
For automotive engines, one of the concern is the economy of scale: it is pointless to make an engine, to invest in all the development cost, if only a handful are produced. And it is pointless to make an engine that is meant for a wide distribution unless the cost of the final product is attractive, and that the maintenance expertise is properly widespread. So again, innovation tends to be introduced very slowly.
And you cannot count on auto racing to act as a test bench for such innovations, as the rules there are often actually meant to limit how innovative one can be...
Hawker Tempest
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Hawker Tempest MkV Cutaway Drawing Photo Mugs Hawker Tempest MkV Cutaway Drawing.... |
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A Soldier in the Cockpit: From Rifles to Typhoons in WWII (Stackpole Military History) $1.98 "I could see a carpet of twinkling lights from the ack ack all along the rail sidings which bordered the canal. I dove onto these with my cannons going. Then suddenly, when the attention of all the guns turned on me, I realized how foolhardy I was being. I ran the guns along the row of rail trucks--opened the throttle wide and pulled straight up for the clouds--with tracers crossing in front and o... |
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The Hawker Typhoon and Tempest $31.95 ... |
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Typhoon and Tempest Aces of World War 2 (Osprey Aircraft of the Aces No 27) $22.95 Hawker Typhoon and Tempest - two aircraft types with widely differing reputations. The former was a technical nightmare redeemed as a ground attack machine, whilst the latter proved to be the most superlative low and medium level fighter to see service with the RAF, and arguably any air force, during the latter stages of World War 2. With 246 enemy aircraft destroyed by the Typhoon and 239 by the ... |
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Hawker Heroes Add-on for Microsoft Flight Simulator FS 2004 and FSX $21.49 Hawker Heroes Add-on for Microsoft Flight Simulator FS 2004 & FSX... |
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Airfix A02094 1:72 Scale Hawker Tempest V Military Aircraft Classic Kit Series 2 $6.60 1-72 Scale. Highly detailed kit by Airfix complete with instructions and decals. Skill level 2.... |
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British Hawker Tempest V 1-72 by Academy $9.25 1/72 Scale. Wingspan measures 6 3/4 inches. All Academy kits are highly detailed and come with detailed instructions and waterslide decals.... |
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Minicraft Models Hawker Tempest V RAF 1/144 Scale $6.93 This aircraft was originally intended to be an improved version of the RAF Typhoon but since the redesign ended up being so extensive, the airplane was re-named the Hawker Tempest. The Tempest proved to be a fast and capable fighter that distinguished itself in lateWWII as one of the few fighters capable of intercepting the V-1 flying bombs as well as challenging the new German ME-262 jet fighters... |
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14646 1/144 Hawker Tempest V RAF ... |
