Motor Sticks and Tail Booms

[klastyioer]

hello,

so i had a few questions regarding motor stick and tail boom proportions

according to the 2018-2019 rules, the wing is quite small. they never specify tail or prop sizes which leaves you room to experiment. with such a small wing, you def need a larger tail and some tweaking for motor stick & tail booms. if youre doing traditional 2 piece motor stick and tail boom, with a wing to requirement and a medium sized prop, what would be your recommendations for the motor stick/tail boom proportions? any mass recs. either for how heavy the piece should be?

[bjt4888]

Katie,

You probably saw in the rules that the airplane is required to be a monoplane and the wing is required to be the largest horizontal lifting surface at 35 cm span and 7 cm chord (my words; not official rules wording). My interpretation of the rules is that the horizontal stabilizer can be almost as large as the wing. This type of configuration is essentially a tandem, which has certain slightly different trimming and flying characteristics than a more conventional large wing, small stab.

As propeller and amount of rubber is not limited, there is a lot of room to experiment. Long rubber motors are a little easier to operate on a longish fuselage, but a long fuselage will possibly need reinforcement to avoid bowing under the tension of the motor. A shorter fuselage, like 12” can be used for a long motor, you just need to take steps to avoid knots bunching near the hooks during unwind.

You could see Bill Gowen’s plan and write-up in the Hip Pocket Aero forum for ideas. His approach is a little different than the Freedom Flight kit; either is probably competitive.

Bill’s plan includes the various densities of wood and dimensions of carbon parts.

Good questions.

Brian T

[DarthBuilder]

Anyone using the senior flyer kit? If so what times are you guys getting with it?

[klastyioer]

Anyone using the senior flyer kit? If so what times are you guys getting with it?

not yet but we might try and see what the freedom flight kits are like

[bjt4888]

The four teams that I am coaching have finished six of the Freedom Flight kit airplanes and have ten more partially completed and they are very good airplanes, as usual.

We are using a number of modifications, but, the unmodified design would be very competitive too.

Brian T