foam core question

[Dean Pappas]

Hi Nat,
The long socket and joiner tube makes sense. Now what does your plane weigh? I know that it isn't 11 lbs! If it is around 8 lbs, like I expect, then one should be careful in extending that technique with heavier ships and/or shorter tubes. 
 
Mark, I once had a plane suffer the tube tear-out failure. Fortunately, I successfully landed my new, super-dooper variable geometry winged Desire 120 and made a repair. I don't think that I still have the drawing I did for a column in FM about 10 years ago. I'll look. The neatest method, in my opinion is to cut the wing core completely in half (make the kerf 1/8" wide) and white glue the 1/8" lite-ply rib with tube hole and lightening holes, taking care to keep it straight by curing the glue in the weighted core beds.
Hope it helps,
Dean P.

-----Original Message-----
From: Nat Penton [mailto:natpenton at centurytel.net]
Sent: Friday, April 16, 2004 12:34 AM
To: discussion at nsrca.org
Subject: Re: foam core question


Mark I did not use support at the end of the wing tube because the cores came to me sheeted. In this case I let the socket go into the panel 18" and the tube almost 16". I have about 700 flights with no problems. If I did have a problem it would be easy to remove a precise amount of foam and replace with a light weight filler ( SuperFill ). Forget about carbon strips and use .5oz carbon mat to apply the epoxy to. It will be lighter by helping controll the amount of adhesive and, most important, provide a torsionally very stiff wing and aileron.        Regards   Nat

----- Original Message ----- 
From: Mark Hunt <mailto:flyintexan at houston.rr.com>  
To: discussion at nsrca.org 
Sent: Thursday, April 15, 2004 9:16 PM
Subject: foam core question

Sirs:
 
As a newbie to cutting foam cores, I have a question regarding how to strengthen the wing panel.  Does the preferred method include attaching some c.f. strips to the inside of the skins?  Should they extend from the root all the way to the tip?  I know some guys feel it is a must to also use a false rib near the end of the tube sleeve also?  I hear that some guys (r u out there Nat?) are confident without any false rib or c.f. under the skin....?
 
I cut the cores earlier tonight (to rebuild my 2M after a mid-air) with the help of a friend, and they turned out just beautiful.  I have a nice plan to machine a drill jig for cutting the spar tube hole...so that's seems to be solved.
 
Thanks in advance for the help...

 
Mark
www.geocities.com/markhunt_2000/INSIGHT
 
 

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