Re: Coslick style deflection testing

From: William Gowen <wdgowen_at_gmail.com>
Date: Sun, 21 Oct 2012 15:48:20 -0400

IMHO what you really want to do is select the best spars from the wood
you have available. If you use this approach then the actual test method
isn't that important. Just set up the deflection tester so it will work
with the length of your spars, then hang a weight on the end of the spar
that will give you a readable amount of deflection. A deflection of an
average 1/2" will probably work. Then all you need to do is pick the
ones with the least deflection.

After that - or maybe before that - I weigh my spar candidates and sort
them out according to weight. Obviously you can get super strong spars
if you're not worried about weight. My last 2 props (built a few weeks
ago) used spars that were in the range of 24 to 28mg each.

On 10/21/2012 2:11 PM, Mark F1diddler wrote:
>
>
> Per p.10, INAV 120, half spar for F1L is 7.25." Deflection goal is .5"
> at 6" point. Doesn't this mean the 6" mark on the scale base, measured
> from 0 mark, which is center of the right-most holding dowel, per
> p.26, INAV 107? But if space between holding dowels is 1.6", then a
> half spar length (7.25") is not long enough to test at 6". If I mark
> spar at 6" its own radius, deflection is only 3/16" for a .030g half
> spar. Can't be right. What am I missing?
> TIA,
> MB
>
>
Received on Sun Oct 21 2012 - 12:48:30 CEST