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Building Tips and technical articles. => Building techniques => Topic started by: roger on May 01, 2007, 06:23:30 PM

Title: hard balsa
Post by: roger on May 01, 2007, 06:23:30 PM

i need some hard balsa for a buster fuse. not that stuff you get at hobby town. also some harder stuff for a slab wing like in the kit, this is a simple kit thanks

roger ??? H^^

Title: Re: hard balsa
Post by: Jim Oliver on May 01, 2007, 07:03:49 PM

Roger,

I might be able to help---what size?

Jim

Title: Re: hard balsa
Post by: Jim Thomerson on May 02, 2007, 02:58:54 PM

Are you saying Hobby Town now stocks contest balsa?  Wow, have to check that out!

Title: Re: hard balsa
Post by: roger on May 02, 2007, 05:14:18 PM

well they aint got the hard stuff!!!! mw~

Title: Re: hard balsa
Post by: roger on May 03, 2007, 04:20:06 AM

jim i need 1 pc. 3/8x4x24 and a pc. 1/4x4x24 and 1pc. 1/4x4x24 can you help

roger

Title: Re: hard balsa
Post by: captcurt on May 03, 2007, 06:55:51 AM

Just out of curiosity, why would you want to build a CL plane using especially hard balsa??

Most folks are on a lifelong quest to make the fuse as light and stiff as possible--using hard lumber is contrary to that objective.

There are several simple ways to build a acceptably stiff fuse using light wood.  Especially for a small moment plane.

Curt

Title: Re: hard balsa
Post by: roger on May 03, 2007, 03:03:22 PM

 i dont know i thought maybe the sig buster might have had sometougher stuff rather then soft in the kit. seems to me that some balsa kits had some stronger stuff in them, like for the fuse..

thanks roger

Title: Re: hard balsa
Post by: captcurt on May 03, 2007, 03:38:07 PM

Alot of the older kits had wood selected more for its die cutting characteristics than weight or strength.  Especially for a 3/8 or 1/2 thick fuse piece, die cutting of soft material causes alot of crushing--so they made it firmer.

Putting silkspan or other fabric over the wood with dope or other material will make the fuse adequately strong.  No need to go overboard as the Buster fuse isn't that long.

A long-moment stunter, like a cardinal for instance, needs both a light-weight fuse to keep the CG in the correct plae and it needs to resist flexing to keep the control surfaces in alignment.  On stock kits, you can watch the fuse flex from outside the circle.  In those cases, glass or carbon cloth with epoxy, a built-up frame fuse planked with 1/64 ply. or some more esoteric fuse construction can be beneficial.

On one of my "full-out-profile" models (the little plane that could), I used a 4 Lb/cuft plank fuse with a carbon tow truss wrapping around the plank.  Appears as a series of bridge girders bracing under the silkspan.  It is one of the stiffest and lightest fuse structures I have seen.

FWIW

Curt

Title: Re: hard balsa
Post by: Jim Oliver on May 03, 2007, 07:35:07 PM

Roger,
Not sure you really want this stuff---I have two pieces of hard, very heavy balsa.  Thichness is 5/8 in.
width is 4 1/4 in. and length is 37 inches.

This is some stuff that Lone Star used to protect the light stuff which I ordered from them--the light stuff is very nice, too!

Please advise.
Jim

Title: Re: hard balsa
Post by: roger on May 03, 2007, 09:08:01 PM

thanks jim ill try the lite stuff....
roger