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Classic Wings Magazine WWII Naval Aviation Research Pacific Luftwaffe Resource Center
When Hollywood Ruled The Skies - Volumes 1 through 4 by Bruce Oriss


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 Post subject: First noise in 85 years
PostPosted: Wed May 20, 2009 2:07 am 
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http://www.youtube.com/watch?v=Nk9Dl6RZxmQ

http://www.youtube.com/watch?v=HXf3StrR ... re=related




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PostPosted: Wed May 20, 2009 7:04 am 
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heck of a way to take your castor oil!!!

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PostPosted: Wed May 20, 2009 7:17 am 
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Very Cool!! I really like the explanation.

At the risk of displaying my ignorance (something I have, in abundance:)

I'm not clear on the valve timing. I got that the the engine does two complete revolutions to complete all four cycles. I also got that, on the power stroke. the engine fires at 20 Before TDC and the valve opens at about 110 after TDC. Does the valve stay open all the way around through the exhaust stroke, closing after it passes about 180 TDC the second time?

Also, I'm not sure that I understand the inherent limitation that prevents the use of a carburetor. I'm guessing that it's related to the single valve operation as it sounds like it might not really be effective.

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PostPosted: Wed May 20, 2009 11:01 am 
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I should've re-read my paperwork before talking to the camera, my angles were a little bit off. The valve opens at 85 degrees after TC, stays open the rest of the power stroke, all of the exhaust stroke, and 115 degrees of the intake, so a total of 390 degrees.
This diagram is for the 100 Gnome, but I think the 160 is the same.

Image

As for the carb, the early 50 hp Gnomes (like George's) had a rudimentary carb, but for some reason they didn't use them on the bigger 100s and 160s. I've always been told that it wasn't practical because of the way the fuel/air was delivered to the cylinders through ports in the cylinder base. Despite what is commonly written, pretty much all of the rest of the rotaries did have carbs, with a slide valve regulating the air and a needle valve attached to it to regulate the fuel. LeRhones, Clergets, and the German Oberursal all had this.


Gnome cylinder, about the same cubic inches as an R-985, but a lot less cooling fins
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Selector unit taken in half, showing the brass disc with fiber inserts that the brushes go against to "throttle" the ignition
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PostPosted: Wed May 20, 2009 7:10 pm 
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Baldeagle,

Many thanks, and that diagram is really cool and helpful!! It gives me a good place to get a start in understanding some of the nuances of these engines.



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PostPosted: Sat May 23, 2009 7:00 am 
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Excellent Andrew! Would love to have one just to run it from time to time! How far along is the Nieuport?

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