khodges
Posts: 5438
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Joined: 7/3/2003
Last Login: 2/18/2011
From: newton,
NC, USA
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That's too funny, Scott. Very similar to something I did not too long ago. I was working at my bench, I forget exactly what I was doing, but it involved leaning over the bench. Well, I unknowingly knocked over the small bottle of medium Ca, which proceded to drip against me and the edge of the bench. When I straightened up, I almost brought the bench with me; the Ca had glued the edge of the bench to my belt. At least there wasn't any physical evidence i couldn't hide; just a chunk of my belt permanently affixed to the edge of my workbench.
Well, YEE-HAAA. I started the WACO for the first time today, to make sure it would even run  , and to check the throttle settings. I ran maybe half a tank through it (16 oz tank) and it runs great. I'm running a mix that's a bit leaner on oil than 32:1, not quite 40:1 with Klotz synthetic as the lube. Transition from just above idle to midrange is a tad muddy, but I didn't touch the needles from the factory settings yet. I tried to tach the top end, but my tach wasn't cooperating. It was a bit gray outside, a thunderstorm was brewing and there wasn't very good reflection from the prop for the tach to read, but the engine really revs. I have an 18-6 Master Airscrew Classic on it right now, that will likely be my flight prop. I may also try an 18-8. I untied the plane from its hold-down and taxied around the yard to get an idea of thrust. With the elevator neutral, 1/4 throttle starts to lift the tail, and at 1/3 you have to put up elevator to keep the plane from nosing over in the grass. A short burst of throttle from standstill gets the plane rolling quickly. My guess is a takeoff roll in still air less than 100 feet. Ground handling is excellent, and it will turn 180 degrees in about 1-1/2 wingspan with my tailwheel setup as I have it. I'm using the same servo for rudder and tailwheel. I have the rudder arms on the inside holes of the servo arm, and the tailwheel is on the ouside, so it deflects more than the rudder at a given stick position. I have negative 40% expo in the rudder. I think it and the elevators will be VERY effective, so I wanted to decrease the sensitivity around center. The only thing I will probably do to my setup is add a "servosaver" spring linkage to the tailwheel control rod. I'd like to be able to spring load the tailwheel itself to reduce shock to the tail when it sets down. I have an idea to try but haven't really thought it through or experimented yet.
Master Chief, funny you should mention your prop thoughts. I was talking to a guy at or club meeting last week about what he thought I should try on the Waco. He flies a lot of 1/4 scale WWI bipes, and is actually working in a 1/4 scale Waco D like Claude's right now; it's an overhaul of a long-built plane, mainly a re-cover and new electronics., and runs mostly G-26 and G-38's. He recommended the higher pitch props to me because he says the induced drag really slows you down off throttle and the higher pitch props allow more thrust faster. He tried some 4-pitch props once, he said, and they wouldn't move the planes fast enough for good performance even at full throttle. Performance was "mushy" in his words, and he couldn't keep enough air over the tail surfaces on the ground (during landing roll-out especially). Of course he's got a tail skid instead of a wheel, and the rudder authority on most of the WWI stuff ain't that great anyway at low speed. When I mentioned the 18-6, he said that was a pretty good one to start with, and to maybe try the 18-8. I guess all of them will fly the plane, it sounds like a good experiment while getting used to the flight characteristics. I believe the UMF/YMF had a 98 inch diameter prop, so 20 inches would be right on for scale. Once I get the tach to work and see what I'm turning, I might even try a 20-something, but I'll initially fly it with the 18.
< Message edited by khodges -- 5/17/2007 4:27 AM >
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Club Saito #2, WACO Brotherhood #20. What other trouble can I get into?
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All Forums >> RC Airplanes >> Golden Age, Vintage & Antique RC >> RE: WACO YMF 
RE: WACO YMF - 
That's how the plastic model car designers do it in the field. I helped Revell/Monogram do some race car stuff a few times. 
