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Old 06-29-2018, 06:57 PM   #1  
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Default Hand Propping

I was watching The Great Waldo Pepper for the zillionth time and noticed something about how they hand propped.

Rather than pulling through an intake and compression cycle clockwise (pilot's view), they pulled it counter clockwise. When the crank was at or near TDC of the exhaust stroke, the prop was released, and the compressed air kicked the engine through a firing/ignition cycle. Is this the norm? Or is it only done on some engines?
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Old 06-30-2018, 05:45 AM   #2  
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Is this the norm? Or is it only done on some engines?
No idea. But notice the prop bolted right to the engine case in the video example attached?


[URL="http://www.military.com/video/aircraft/engines/starting-up-a-ww1-rotary-engine/3812381667001"]
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Old 07-01-2018, 04:41 AM   #3  
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That defines a rotary engine At least before Wankel took over the term.
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Old 07-01-2018, 04:55 AM   #4  
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That defines a rotary engine At least before Wankel took over the term.
I think I see what you mean. Except the whole crankcase spins, wild. Never noticed before.
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Old 07-01-2018, 06:15 AM   #5  
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They were good in that the engine stayed cool running on the ground since the cylinders had airflow all the time. They bled oil and the torque issues were 'interesting.'
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Old 07-01-2018, 08:44 AM   #6  
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They were good in that the engine stayed cool running on the ground since the cylinders had airflow all the time. They bled oil and the torque issues were 'interesting.'
I imagine they also had more engine inertia than other piston engines, possibly turbojet-like response (which is not good).
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Old 07-01-2018, 02:28 PM   #7  
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Early inline engines had a flywheel to balance out the power strokes. The rotary engine had a better power to weight ratio since the case and cylinders did double duty as a flywheel.

Some of the early rotary engines were controlled by turning the ignition on and off. This led to fouled spark plugs. Later ones had primitive throttle and mixture controls and it was better to shut the fuel off and keep the plugs firing on approach to landing. The ones I've heard at air shows power right up when started, nothing like JT3C response.
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Old 07-05-2018, 08:34 PM   #8  
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Here’s a good video of a currently operation original Camel.

https://youtu.be/Hq78ZocOAkY
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Old 07-05-2018, 11:16 PM   #9  
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Recently got to see a 100 percent authentic Sopwith Pup do a full power runup. Complete with Blps and Castor oil a plenty.

I remember hand propping my first plane. It was a tiny little T-crate. My Instructor (tailwheel rating) was an old Pelican Airline Pilot. I, a freshly minted Commercial Pilot. The crate had no electrical system, so she had to be hand-propped. He got in the cockpit, made all the right calls, and I flung the blade like I had seen in all those King/Jeppesen videos.

Welllllllll, I thought I did; but I didn't. I flung it like I was holding onto a 3 ft chainsaw at full power. I backed away as if it were radioactive. He just laughed at me. "Crucified Christ! It's not an F-16 inlet!" Over and over I flung it like it was a rabid dog, like it had Ebola.......I was simply terrified for some reason. Then he got out, rolled his eyes dramatically and said "stand right next to me." He chocked the bird, came over, grabbed the prop like he had flown her for for 25 years (which he had) and did the old Waldo Pepper fling. The engine popped to life immediately. I stood right next to him, less than a foot from the prop......and was unharmed. I quickly loss my fear after that (and have hand propped many birds since)

How many Millenials (sadly I am one) have hand propped a bird? I wonder?

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Old 07-06-2018, 02:39 AM   #10  
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Being an old J-3 guy, the mistake most make is standing too far away. If you lose your balance you will fall forward. (Not good). Stand close in, and you will fall backward and that big baby will roll right over you. If you are complete chicken ******* you can seaplane prop from the right rear.

Last edited by badflaps; 07-06-2018 at 02:40 AM. Reason: speling
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