Re: Re: Any interest in a Group buy of Polyimide tubing?

From: William Gowen <wdgowen_at_gmail.com>
Date: Sat, 11 Jan 2014 12:24:06 -0500

A Geauga post sander is a good tool for the job but there's only one of
those in existence.
On Jan 11, 2014 12:17 PM, <Warthodson_at_aol.com> wrote:

>
>
> Leo,
> Thanks for the detailed information. That helps me understand the reasons
> behind some of the choices people are making.
> One question, what method do you use to make the round wing & stab posts
> to fit the .064" I.D. tubing? I assume they rely on a friction fit (no
> glue) so the diameter would be critical.
> Gary
> -----Original Message-----
> From: leop leop_at_lyradev.com
> To: Indoor_Construction <Indoor_Construction_at_yahoogroups.com>
> Sent: Sat, Jan 11, 2014 8:29 am
> Subject: [Indoor_Construction] Re: Any interest in a Group buy of
> Polyimide tubing?
>
>
> Everyone,
>
> There are more successful F1D fliers to copy but here is the polyimide
> tubing sizes I use for my F1D. My vp hubs use 0.072" ID tubing to hold the
> spars. I use both thin wall (0.00125") and thick wall (0.00375") for the
> hubs depending on the particular hub details and the desired final weight
> of the hub/prop combination. The thick wall tubing weighs about 9mg more
> than the thin wall in my F1D vp hubs. My prop spar sizes, 0.072", (as well
> has the vp tube ID) are the same that Ivan Treger specifies in his 2010 an
> 2012 F!D plans. I do not jam a square spar into the tube but rather have
> rounded ends on double tapered spars. This is important as the spar/tube
> combination provides the hinge support for the vp hub. The prop spars are
> locked to the tubes using a drop of Ambroid cement although the fit is very
> snug. There is at least one world class flier who has us ed Treger type vp
> hubs with 1/16" diameter spars. Spar size design decisions take more into
> account than just diameter (wood type, density, boron, etc.). BTW, my F1M
> and PP vp hubs use the thick wall 0.072" ID tube and corresponding size
> prop spar successfully. This does not mean that my F1D parts are too big
> and strong but rather reflect the balsa densities used (6# or less for F1D
> and 8# or more for the F1M/PP) for the prop spars.
> I use 0.064" ID thick wall (0.00375") polyimide tubes for all of my
> wing/stab spar to post connections. This is a design decision as I have
> found that the thin wall tube does not work for my designs and planes.
> Others have made the choice to use thin wall tubing in these circumstances
> and their planes have been quite successful. Again, such decisions are
> made by each individual. I also use round wing and stab posts. Others
> successfully use rectangular posts inserted into the (initially) round
> tubing. Again, these are individual design and build decisions and work
> well for the fliers that use the various different methods. BTW, I use the
> same size wing post tubing for my F1L and LPP planes.
>
> Finally, before Small Parts was bought out by Amazon, they had a very
> good selection of polyimide tubing sizes. However, I purchased most of my
> current supply of polyimide tubing from Furukawa, a Japanese manufacturer,
> as Small Parts had not yet started to carry a good selection of polyimide
> tubing when I first started using the tubing (for use other than in indoor
> planes). Mike Kirda has found an excellent US source for polyimide tubing
> in just about any size imaginable (Kudos to Mike) and at a reasonable
> price. The tubing is, I believe, actually made in the US. The only
> problem is that the minimum quantity for a purchase of any particular size
> is large (often 50' or more). Thus, Mike is trying to put together a group
> purchase. Again, many kudos to Mike.
>
> LeoP
>
>
Received on Sat Jan 11 2014 - 09:24:08 CET