Archive of the Yahoo! Groups mailing list for the Bug hand-launch glider 2002-2018

From: Tim Schuh <tim@...>
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