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Johng -> maybe Graupner (10/28/2002 9:56:42 PM)
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[QUOTE]That up&go on the DG800 sounds like one of the Graupner units.
Is it belt-driven, with the motor in the fuse, and the belt is tensed when the unit is extended ?[/QUOTE]
Yes, that's it. It has the 11x6 prop on it. I wonder if a 12x5 (Graupner) or 12x4 (APC) would give me better climb?
[QUOTE]That is a problem inherent to up@go power plants, since the propshaft ( and thus the thrustline) will always be at a certain distance from the C/L of the sailplane, and therefore generate a nose down moment, even if you tip it back. The only way to overcome this, is to apply up elevator when advancing the throttle, either manually, or through a mixer.[/QUOTE]
Hmm, I've seen mpg clips on-line of up&go launches, without the pitch tendency I see. Problem for me is, at zero airspeed, there's not enough elevator to compensate for the pitch down.
Do you find that prop-blast over a deflected elevator is enough to keep the tail down??
BTW- the reason for the tip-back on the prop, would be to increase the down-angle of the prop-blast on the stab and increase the self-trimming tendency. Unfortunately, I checked the possibility of doing this on my plane, and it isn't practical.
I suppose on pavement, the rolling resistance is less, and it would be easier to get the plane up. I believe for grass I will pursue 2 things- a takeoff dolly to keep the nose level and a bungee assist. The bungee assist will keep me from leaving valuable electrons in the grass anyway.
Any suggestions on the bungee assist? I intend on using the tubing from a heavy duty high-start and either a chin-mounted hook or tow-release. Since the motor is so easily removeable - I plan on flying from the tow at some point as well :cool:
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