Thanks for the useful information.
The prop I'm making now is symmetric relative to the spar. This is the first time I've rounded and tapered the spar -- wow, really time consuming. I'm gluing the spars to the blades at this moment.
As for rubber size, is it possible that my 0.050 is similar to your 0.062"? Because I measure 1.2g of my 0.050" to be a 16" loop. You mentioned that 17.5" of your 0.062 is 1.3g. Do we have different (x,y) cross section measurements? I have often wondered what is the typically "y" dimension when we say for example the rubber is 0.062" (x=0.062")?
--- In Indoor_Construction_at_yahoogroups.com, "Bill Gowen" <wdgowen@...> wrote:
>
> At USIC my launch torques are typically under .2 in-oz and at LH typically under .3 in-oz. My
> models don't handle high torque very well because of my trim method.
>
> All my F1L props are made on a 28" pitch block. Pitch changes are made by twisting the spars. I
> have one block for LPP blades that I believe was made for 24" pitch.
>
> For F1L I build props as 2 sub-assemblies of a blade and spar for each side. This allows you to be very precise about matching the spar orientation, size, taper, deflection, etc. A hub is made from a short piece of balsa mounted on the prop shaft and the sub-assemblies are glued to the hub in a pitch gauge.
>
> My F1L props are big. The blades are 1.5" x 5.75" with 3/8" behind the spar. The blades are from
> .009" or .010" 4# or less wood. In damp weather these props are a disaster because they are like
> wet noodles. On my last trip to Lakehurst I got trounced by Rob Romash because I didn't have a
> prop that would work. Blades mounted more symmetrically on the spar would be less likely to have
> this kind of problem in damp conditions.
>
> My models would hardly fly on .050" rubber. Your results may be different.
>
>
Received on Fri Apr 09 2010 - 17:18:04 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:46 CET