I'd like to put in a contrarian view here. (actually I've written about this a number of times in the past) Part of the droop boom concept that I use on most of my models includes trimming the model to fly with the MS level so that the prop is pulling in the direction that the model is flying. This usually means that there is a lot of incidence in the wing. Some of the plans I've seen show as much as 7 degrees of wing incidence.
I don't fly F1D but I think the original concept was developed for F1D by Bernie Hunt, Ron Green, Dieter Siebenmann and others. My F1M, F1L and A6 all use this system and have done pretty well.
----- Original Message -----
From: RLBailey_at_care4free.net
To: Indoor_Construction_at_yahoogroups.com
Sent: Thursday, December 13, 2007 5:41 AM
Subject: Re: [Indoor_Construction] F1D CG poll
Tapio
Models such as F1D and F1L generally fly better with the wing and thrustlline parallel to within about a degree. It seems that downthrust is bad for efficiency. The effect of extra fuselage drag is more than offset by the efficiency increase from removing the downthrust, thereby allowing the tail to carry more of the aircraft weight.
Bob
----- Original Message -----
From: Tapio Linkosalo
To: Indoor_Construction_at_yahoogroups.com
Sent: Wednesday, December 12, 2007 1:11 PM
Subject: Re: [Indoor_Construction] F1D CG poll
On Tue, 11 Dec 2007, Timothy Chang wrote:
> It seems the common trend is often to leave the wing close to 0 degrees.
> 1 or 2 degrees at most, and then to have considerably more angle in the
> tailplane. My F1D models like flying with around .45" of incidence in
> the tailplane.
What is the difference between putting the (positive) incidence to the
wing, or (negative) to the tailplane? I assume that with the same decalage
the model will attain the same wing incidence relatice to the flight path,
so for a model with 0 in the wing and negative on tail, the flight
attitude will be more "tail down", which translates into needing more
downthrust on the prop, and hanging tail will mean slightly more vertical
clearance between wing and tail, while the fuselage will produce more drag
being mode inclined to the incoming flow? Is there something that I miss?
-Tapio-
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Received on Thu Dec 13 2007 - 11:32:19 CET
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