RCU Forums - lifting tail

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RE: lifting tail

I'm pretty sure I've seen old free flight designs with a lifting tail mounted upside down. I shouldn't bring that up here because it is confusing to the RC trainer issue. The point is the designer either had a preconceived notion that it would do some good.....

or

...he actually tested the design with different tails until he found one that gave his design good flight characteristics.

So, I wonder if the designer of the Telemaster tried a flat stab and had elevator trim issues?

Usually that problem can be trimmed out by raising the rear of the wing slightly.

RE: lifting tail

Quote:

ORIGINAL: tripower222

I am going to keep my eye out for an old used Telemaster apperently they have a flat bottom airfoil stab. First I will see if it will even fly, dosent sound like it will. then I'll put a flat stab on it and see if it has a tendancy to gain more altitude with speed. Wonder why they did it on the Telemaster?

The Telemaster is not a typical design.
Check the attached scan of a plan.
Note that the wing and stabilizer incidence angles are given as 4.5 and 2 degrees; hence, the geometrical decalage = 2.5 degrees (which increases in flight due to downwash of the wing).
Those are more than 2.5 degrees of longitudinal dihedral; hence, the model is selfcorrecting and speed sensitive.

The AOA of the stabilizer is negative, althought the airfoil, being cambered, would lift more for positive AOA than for negative AOA.
This is suitable for models that have the CG aft the aerodynamic center of the wing, but still located ahead of the Neutral Point, according to Andy Lennon's book.

The engine firewall has 3 degrees down thrust and 2 degrees right thrust.

RE: lifting tail

Quote:

ORIGINAL: HighPlains

...with a lifting tail if I remember correctly. Or more correctly, he controlled the computer(s) that controlled the airplane. Four computers that voted to decide what the correct solution was to maintain flight. On a later variant, the tailplane was enlarged to enhance the load the airplane could carry. I think that was the C/D version. It's been such a long time since I've read Aviation Leak.

Yes, and it was statically unstable, but the easiest thing to fly in the world.