Re: RE: Survey of U.S. F1D fliers before 55 cm rules change

From: Don Slusarczyk <don_at_slusarczyk.com>
Date: Fri, 07 Feb 2014 23:47:16 -0500

18" sticks on 65cm F1D buckled easily unless you used small props around
20" diameter and ~32-34" pitch and ran longer thinner rubber. Typically
if you added some boron the first and last 3" that helped the 18" stick
as that is where they were prone to fail. I then dropped back to 16"
sticks and then finally down to 14" when flying 22/40 props and that is
when my flight times went up to the 48 minute mark. 14" sticks were
surprisingly much stiffer than 16" which did buckle periodically. On the
14" I would typically use 3 boron fibers on them and a single bracing
post in the center of the stick and they never buckled on me even when
flying on 14" loops weighing 1.4 grams and .7 in oz launch torque. You
could abuse a 14" stick pretty good. Models back then also had braced
wings and that braced wing actually added some torsional stiffness to
the motor stick. When I flew unbraced 65 cm for a short time I had to
drop down in prop diameter to reduce stress on the stick so had props
that ran in the 50-55 rpm average compared to 40-45 rpm on braced models.


> Unlimited rubber wouldn't lead to 18" motor sticks. Most 65cm models
> had sticks between 14" and 15". People were even experimenting with
> 13" sticks before the rule change.
>
Received on Fri Feb 07 2014 - 20:47:05 CET