khodges
Posts: 5438
Score: 126
Joined: 7/3/2003
Last Login: 2/18/2011
From: newton,
NC, USA
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'geek and mobyal---- This is one of the things we discussed, the fact that the Pica kit gear is permanently installed with no way to remove it for repairs. This is one place I think the ARF has the advantage over the original kit. The ARF has the traditional grooved rails and the gear is made as a unit that screws to the rails using standard plastic gear straps. There is a removable "belly pan" that fits between the legs and secures with a couple of #4 screws. It really looks clean when finished and wouldn't be a difficult mod on the kit, according to Jay, who looked mine over pretty closely today. This pan also allows limited access to the tank area, without having to take the bottom wing off.
The wheelpant attachment would be an integral part of whatever I try to come up with, and I would also include the fairings from the pants to the gear legs. My little screws are working on mine for the time being, although there's no way I can fly mine until I replace the gear. Thank God for headwinds; the breeze was picking up when I landed, and I had relatively little groundspeed when I touched down.
I am going to devote a lot of my scale data acquisition (pitcher takin'  ) to the main gear of whatever YMF I can get close to at Creve Couer this week. John, I have the picture of the Pepino tailwheel in my files, I'd love to do it, but the way it pivots fore-and-aft, although true to scale, isn't compatible with my steering linkage. Jay looked at mine and thinks it's an okay design, and says he can make one like it from steel that won't come apart from repeated use. My metallurgical skills are limited to brass and solder, and while adequate for looks, just doesn't hold up under my landings  .
Another thing we discussed not related to hardware issues was wing incidence and setup. When I completed my plane, I propped up the rear so the tailplane was horizontal and therefore, zero incidence, and measured the wings relative to that datum. Both my wings are at positive 0.5 degrees. At half throttle in the air (a good cruise speed for my model) I have about three or four clicks of down trim on the elevator for level flight. Jay suggested making the top wing negative, relative to the bottom. This would reduce the tendency to climb under power and allow one wing (bottom in this case) to stall before the other, making the overall stall more gentle. I feel that given the amount of stagger in the wings, the top wing should stall first, which would allow the plane to "fall forward", or pitch down. The c/g on this plane is right at the leading edge of the bottom wing; if the bottom wing stalls first, the tendency will be to pitch the nose up, because the center of lift will be at or forward of the c/g if the plane is flying on the top wing alone. In conditions where one wing is stalled, airspeed is likely already slow, and the pitch-up will aggravate this and possibly place the plane in full stall. With a tendency to pitch down, it allows the plane to get back into a flying speed more quickly (unless you're only two feet up, in which case neither setup is good news).
So far, I haven't seen any bad tendencies with the incidence equal on both wings. It does tend to climb when flying into a breeze or with full power, but not so severely I consider it a bad handling trait. As a matter of fact, I find it very similar to my Cub in its trim characteristics. It wants to "leap" off the ground a tad when it reaches flying speed if you hold neutral elevator, but a slight touch of down keeps it on the ground and then relaxing that allows it to come off. It comes down quickly when you reduce power to about a third, but the attitude can be held with elevator, and I think it lands much better if flown to the ground with about 1/4 throttle and allowed to settle, rather than gliding in off power. As Stickbuilder says, she flies on the wing, and it needs to make lift until the mains are firmly planted.
Jay mentioned that today was probably the first meeting of two members of the Brotherhood; I think the Master Chief knows a couple of the guys from the Florida area. I enjoyed the heck out of today, and have a great sunburn to prove it . This intenet networking is awesome; I'll get to meet yet another brother this week as I fly the friendly(?), expensive(?), lost my luggage(?) skies of Useless Air(which BTW was recently voted the worst US carrier) and wend my way into STL. Maybe I can talk the pilot into flying through the Gateway Arch on his approach, make the flight more interesting; he might have to do it in a 90 degree bank so the wingtips clear. Later.
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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 - 
RE: WACO YMF - 