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Roy Fedden really did try and do it the hard way with an air-cooled sleeve valve.
Whatever it's other faults the liquid-cooled Sabre did not have major cooling problems.
A straight H block engine with poppet valves may have done much better.
As a general rule that's right: However provided the following criteria are met
The following will be the case:
- At least two aircraft are involved, and for the sake of the argument: There will be two aircraft
- Both aircraft have the same armament: Say 4 x 20mm with 150 rpg
- Both aircraft have the same weight when armed, full fuel and oil: For some reason, I'll pick 10,000 pounds
- Both designs have the same wing-area (310 ft^2), same aspect ratio (6), same L/D ratio (13.5%)
- Both designs have the exact same horsepower engine (1875 hp) same critical altitude (24000 feet with ram)
- Design A has a fuel fraction of 11.1% (185 gallons) and Design-B has a fuel fraction of 16.68% (278 gallons)
- Both aircraft are stressed for a g-load of 9g ultimate when fully loaded at takeoff.
- Aircraft 1 & 2 will perform exactly the same when on 100% internal fuel
- Aircraft 2 will have a longer range providing the same basic cruise settings, and combat settings & limits will be used even if both use drop-tanks of the same size and capacity.
- Aircraft 1 & 2's performance will more radically diverge as fuel load goes from 100% to 80%, and from 80% to 50% as the different percentages of fuel will correspond to a different amount of fuel relative to the plane's weight: At 100% weight, Aircraft & 2 have no difference; at 80% weight, Aircraft 2 will weigh 98.85% the weight of Aircraft 1; at 50%, is 97% the weight of Aircraft 1.
- Aircraft 1 & 2's power-loading, maximum g-load capability, and corner velocities will all more radically diverge.
It did but they still weren't using all the volume. ANd there were a number of restrictions on how the plane was to be loaded,flown and even taxied at those high weights. A biggie was that at high weights you HAD to fill the outer wing tanks (they didn't exist on the early planes) to spread out the span loading, you couldn't fill the bombbay with AP bombs, hang a pair of 4000lbs under the plane and just fill the inner wing tanks, you had a good chance of bending/breaking the wing even if the gross weights were the same.But horsepower went up considerably in that time....
Honestly, I'm surprised they never thought of fitting the R-2600 to it.
Pictures taken from the 'Motoren und Strahltriebwerke' book. The 801R was supposed to be outfitted with 2-stage, 4-speed S/C. The 801Q was, IMO, close sibling to the 801E. 801J is noted as 801D-2 with turbocharger.
The graph notes that 801E was to be core for the P. 8035 engine project. Please note the gear speed change at 8.5 km for the 801J, the turbo engine.
'Luftschraubenwelle + Luefter' = 'prop shaft + fan'.
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I believe with big capacity poppet valve H engines you would run into problems with the inlet and exhaust passages being too cramped for good breathing.
Don't know how they planed to get around the problem of cramped gas flow passages.
Concur!
Does anyone know if there are less moving parts to this set up than the "standard" valve layout? Also, it seems to have a weakness if hit in the "watch" mechanism it could take out the entire motor (sort of like liquid cooled engines and their ever so required liquid coolant).
Cheers,
Biff
Simply space the cylinder blocks a decent width apart.
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more photos and story/data here: Arsenal 24H and 24H Tandem Aircraft Engines
engine went about 4000lbs so you need a good sized plane to carry it
The theory is that they are moving but not reciprocating like a valve against a spring, howver I would say the friction between the surfaces, even with oil lubrication probably means very little gain.
There is a motorised cutaway at the Yorkshire Air museum, it makes your brain hurt watching it. Since it runs very slowly but dry you can see the effect of the constant movement, nothing is able to "bed in" against anything else, and the scoring is visible.. Also for a brief period the block machined surface is exposed to the exhaust gas through the sleeve port, this must have seriously roasted the oil.Watched a couple more videos and I agree, there's a lot of metal on metal friction there.
...Russian and German troops didn't dive for cover when aircraft came, they started shooting. The smaller 10-12 man squads the Germans were organised into could probably get 8 rifles firing of which 2 might be semiautomatic Gw 43. The Machine gunner might get his MG42 into operation if he had a stand for it. The NCO or Sargent that ran things would have had a sub machine gun...
There is another thread here that I don't want to look for at the moment is which I took 3-4 posts to cover all the supposed advantages for the sleeve valve engine as listed by Roy Fedden in a talk given in England.
Not trying to take away anything from Fedden but he was comparing his sleeve valve engines to his own poppet valve engines which were 10-20 years older in basic design. He was NOT comparing his sleeve valve engines to P &W or Wright radial engines. Maybe he didn't consider the upstart Americans to be competition?
For instance he claimed the Sleeve valve was more oil tight and didn't leak as much oil into the engine compartment or onto the airplane. I am not claiming the American engines were oil tight but the Bristol poppet valve radial's valve gear was lubricated by grease gun and the valve springs, rockers and pivots were all flapping around in the breeze. NOT enclosed.
Photos were published of all the parts needed for ONE cylinder of both types of engine. Of course Bristol poppet valve cylinders used four valves so there are a lot more parts than a 2 valve cylinder would show. The photo also doesn't show all the gears in the crankcase vs the gears and cam ring/s needed for a single row radial.
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The Mercury and Pegasus didn't get a whole lot of development during the 30s as most of the R&D was going into the sleeve valve engines.
From what I have read about the intrigues of the USA motor and defence industries they are pretty much the same, I hold up Curtiss and its War Hawk ads as evidence.
Nothing wrong with it as a plane but it was no longer the world beater they continued to say it was until production stopped.Hmm - what was so wrong about the Warhawk?