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Duke engine

Gee, what's not to like? :eek:

"Problems associated with the design of the axial piston engine include high oil consumption, high fuel consumption, low rpm limit imposed by previously discussed frictional loads, low overall horsepower, mechanical complexity and complex machining methods needs to allow the engine to stand up to the loads imposed on the components. Additional problems are noted in that, the design does not have a long lifespan when compared to other engine designs due to large numbers of moving parts and relative high stresses. Wear and tear occurs at a faster rate because the engine makes more power pulses per turn of the cam than traditional engines. Lastly, due to very high initial torque and a need for large amounts of coolant, loss of oil or coolant to this design during running will almost certainly result in a catastrophic explosion of the engine because the engine generally has very light casings or shields located in the area around the cams and connecting rods."
 
Whatipedia?

N395V said:
Read this and it doesn't sound like it has real aviation potential.
http://en.wikipedia.org/wiki/Revolving_cylinder_engine...

Especially the part about inevitable catastrophic explosion of the engine...
Click to expand...

That Wikipedia article is about an entirely different type of axial-piston engine, more like the old DynaCam. The Duke seems to use a "wobbling spider" crank, and not the DynaCam's eponymous rotating cam.

Furthermore (and wandering OT), everything on Wikipedia should be considered with some skepticism. I use Wikipedia a lot, and I contribute to it a fair bit, but I am always mindful that the processes that make it what it is do not and cannot protect it from the personal biases, agendas, and conceits of its contributors and editors. A good example of this in action is the recent Qworty Affair.

Thanks, Bob K.
 
http://i456.photobucket.com/albums/qq282/whittfic/bth_IMG_0529a.jpg

http://i456.photobucket.com/albums/qq282/whittfic/bth_IMG_0361.jpg

I had an opportunity to see the Duke engines first hand at a local aviation event about eighteen months ago (see photo links). They are certainly a different animal from the old DynaCam and nothing like the Lycoming. There is a relatively large rotating mass in the form of cylinder block, pistons etc but overall size is smaller than a conventional engine for a stated HP output.

There were two sizes on display. I cannot recall the quoted power outputs of each, perhaps in the 120 - 300hp range? There didn't appear to be any issues with combustion or oil leaks. I'm guessing the technology has moved on since the DynaCam days, and the various Wankel type engines available these days seem to have nailed it, so presumably these guys have taken their cue from them.

Will it develop into anything? Who knows, many have tried and failed in the past but I guess the Wright brothers had their challenges and doubters too...

Clive Whittfield
Auckland
New Zealand
 
From the Duke website:

Cooling

Cooling is achieved with conventional water jackets around the cylinders and ported areas.

Seals around concentric flow passages allow the coolant to enter and leave the rotating cylinder group.

The coolant is then circulated in a conventional manner through radiators mounted on the airframe, using a pump.
 
The Wankel engine, most notably the Mazda Rotary could be considered as a sleeve valve type.
I like the sound and fury of the Napier Sabre, sound files can be downloaded from the net.
Sleeve valves have tremendous advantages in air and exhaust flow, but alas, have many sealing and heat flow problems too.
So far, only the Wankel engine has held up enough to be any kind of commercial success, and continue on to second and third generation, with increased lifespan, power and fuel economy.
It is mass produced, where historical sleeve valve engines required much hand fitting.
Today, CNC machining can provide the tolerance, maybe combined with new lubricants and material science....
I like to see advances in power engineering. I hope something good comes from their effort.
 
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