Bad-Boy Rolls Royce 5000hp

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"The sound of it was enormous," he says. "They reportedly said that when we ran it with an open exhaust during the war, the air raid sirens went off in Nottingham," 15 miles away.
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"The Rolls-Royce Crecy was an unusual British experimental two-stroke, 90-degree, V12, liquid-cooled aero-engine of 1,536 cu.in (26 L) capacity, featuring sleeve valves and direct petrol injection. Developed between 1941 and 1945 it was the most advanced two-stroke aero-engine ever to be built"
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I just read about this while reading about the work of Sir Harry Ricardo, Fascinating stuff, I never did feel that Two Strokes have lived up to their potential.

http://findarticles.com/p/articles/mi_qa5506/is_199806/ai_n21422653/pg_2/
 
The Crecy is awesome, I've seen some (expensive) books on them that I'd love to get.

They made a significant amount of their power through the forward thrust that they developed.
 
Originally Posted By: Camu Mahubah
Two-stroke diesels have been pulling coal and freight for years.

What type of fuel did this Rolls burn?


It was direct injection Gasoline. The exhaust (emitted at twice the speed of sound) produced thrust equivalent to about 1300hp.

The Gas was burned in a stratified charge, with a variable mixture ratio of 15-1 to 23-1, this meant the engine could be quite economical at part throttle.
At 1.5 hp per lb the engine was also smaller and lighter than the Merlin, yet had potential for about twice the power.
 
Originally Posted By: KrisZ
That's why I laugh everytime an auto magazine claims "technological marvel" this or "state of the art" that when they review cars.


Sir Harry Ricardo was a dead set legend.

If you grab a copy of the High Speed Internal Combustion engine, you will see 5 valve per cylinders, DOHC, BSFCs of less than 0.45lb/hphr (on kerosene with 4.5:1 compression ratios.
 
"Sir Harry Ricardo was a dead set legend."

+1

Quote:
"Sir Harry Ricardo (1885-1974) was one of the foremost engine designers and researchers in the early years of the development of the internal combustion engine. He patented the two-stroke engine design, personally developed the engines that would be used in the first tanks, oversaw the research into the physics of internal combustion that led to the use of octane ratings, was instrumental in development of the sleeve valve engine design, and invented the Diesel pre-combustion chamber that made high-speed diesel engines possible. "


Ricardos Vauxhall Raceing engine of 1922
http://www-g.eng.cam.ac.uk/125/achievements/ricardo/page29.htm
 
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My Stihl chainsaws are 30 yrs old. 2 strokes are neat. I also have a 77 Lawnboy 2 stroke push mower. I trim the edges with it. I mix a rich 32:1 then add a capful of MMO for flavor. By definition a 2 stroke is twice as powerful as a 4 stroke of the same dimensions. And I remember the Detroit diesels of yore.
 
Seems that Ricardo's Two strokes tended to have a conventional Oil pan lubrication.
This illustration of his Dolphin engine (he made in when he was 17!) has some interesting features.
http://www-g.eng.cam.ac.uk/125/achievements/ricardo/page07.htm

Note the Left Cyl, that only supplies the mixture to the Right, power cyl, is of a larger diamiter. so the left cyl would effectively Supercharge the power cyl.
I wonder if some kind of Upper cyl lubricant would be necessary, as the left cyl would be well 'washed' with fuel?
I imagine the mixture entering the power cyl would be very turbulent even at low RPM (in keeping with Ricardo's principles)
 
Originally Posted By: andyd
By definition a 2 stroke is twice as powerful as a 4 stroke of the same dimensions.



ummmm....no
 
Originally Posted By: Shannow
Originally Posted By: andyd
By definition a 2 stroke is twice as powerful as a 4 stroke of the same dimensions.



ummmm....no


uh huh, twice as many power strokes.
 
Originally Posted By: mjoekingz28
Originally Posted By: Shannow
Originally Posted By: andyd
By definition a 2 stroke is twice as powerful as a 4 stroke of the same dimensions.



ummmm....no


uh huh, twice as many power strokes.


I believe it comes down to theory. It could produce twice as much power due to it's power stroke occurring twice as often. In reality, it doesn't often happen. Four cycle engine (at least int he power sports world) are catching up to 2s engines in terms of power output, but still have a ways to go.
 
Originally Posted By: mjoekingz28
Originally Posted By: Shannow
Originally Posted By: andyd
By definition a 2 stroke is twice as powerful as a 4 stroke of the same dimensions.



ummmm....no


uh huh, twice as many power strokes.


twice as many (generally) smaller power strokes doesn't double power output.

Look at cylinder filling, volumetric efficiency, compression ratios (theoretical and attained), and they aren't generally anywhere near twice as powerful
 
Supercharging can go a long way to improve the VE, but then you have to power the supercharger. Power lost for power gained.
 
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