From: Tim Schuh <tim@...>
Date: Wednesday, March 21, 2012 6:41 PM
Subject: Re: [BugHLG] Re: Carbon Booms - Goodwinds
Date: Wednesday, March 21, 2012 6:41 PM
Subject: Re: [BugHLG] Re: Carbon Booms - Goodwinds
On 3/21/2012 2:31 PM, raincityflyer wrote:
>
> Make sure you are watching your weights with "retail" CF parts. The OD's may match, but the wall thickness is what kills you.
>
> The final version of the Little Nipper (Swyft 2) uses a wrapped spar and is really stiff. I opted to go this route to fight the flex you get in a pultruded spar. This flex takes a lot of height out of your launch as the wings oscillate up and down after release. The arc can be pretty dramatic.
>
> Same goes for the boom. The whipping oscillation deprives you of launch height as the tail wags back and forth.
>
> Carl designed this plane for a javelin launch with no torsion to the boom. Wing flex was also just a given in those early days.
>
> The LB will work with any combination of CF parts, just watch your weight. As they say - "Ounces are made up of grams."
>
> Stay light!
>
> Chris in Seattle
>
> I can vouch for the P100 fitting into the new AG37 wing, so don't be afraid to try it.
I agree with Chris. I've used P90 and P100 tubes on my 1.2m and 1.5m
woodie DLG experiments without any issues at all. In fact I used a P100
on a 2M woodie floater pod and boom with good results. There's plenty
of stiffness and much lightness. For a quick, very informal comparison
here's what I have on hand and within reach. I got all the CF tubes on
sale and I don't think I paid more than a few dollars for any of them.
I know I got a mess of them for less than $20 shipped to my door in Texas.
All tubes are 36" long.
Generic fiberglass pushrod tube (I think from a Dave Brown pushrod kit)
OD: 0.300
ID: 0.241
W: 22g
SkyShark II (no other markings and I don't remember) CF tube:
OD: 0.387
ID 0.345
W: 17g
P90 tube:
OD 0.280
ID .0240
W:11g
P100 tube:
OD: 0.285
ID: 0.240
W: 13g