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.
----- Original Message -----
From: ykleetx
To: Indoor_Construction_at_yahoogroups.com
Sent: Friday, April 09, 2010 7:20 AM
Subject: [Indoor_Construction] Re: Propeller camber
Do you fly with a lot more back off at USIC v. Lakehurst? At Tustin, I'm planning to fly with 1.2g of .050" (~16"), 26" pitch (on a very flimsy prop), at 2 in-oz. I'm still working on a couple of new props for this weekend.
Do you have separate prop forming blocks for 25" v. 27", or do you make slight adjustments of the prop blade angles at the prop hub? I am wondering practically how many prop forming blocks are needed to get pitches from 18" to 28".
--- In Indoor_Construction_at_yahoogroups.com, "Bill Gowen" <wdgowen_at_...> wrote:
>
> For USIC last year, 17.75" of .062" (1.3 grams) 27" pitch 21:16
> USIC site record in 2007 rubber almost the same, 25" pitch 22:34
> Best at Lakehurst was in 2007, rubber almost the same, 25" pitch 25:26
>
> ----- Original Message -----
> From: ykleetx
> To: Indoor_Construction_at_yahoogroups.com
> Sent: Thursday, April 08, 2010 9:19 PM
> Subject: [Indoor_Construction] Re: Propeller camber
>
>
>
> Hi, Bill,
>
> On your 4% camber F1L prop, what pitch would you use for Lakehurst vs. Johnson City? I understand that the prop spec goes with the rubber. In Laurie Barr's plan, he uses 17.5" of 0.050" (1.025g) with his 26" pitch 10% camber prop.
>
> -Kang
Received on Fri Apr 09 2010 - 09:14:49 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:46 CET