Hangar Flying

Hangar Flying => Hangar Flying => Topic started by: propblade on February 08, 2013, 10:21:26 PM

Title: Using S-glass roving as opposed to flagged UNI for canard cap?
Post by: propblade on February 08, 2013, 10:21:26 PM

Any thoughts on substituting S-glass yarn for the flagged UNI spar cap for a Long EZ? Pro's/con's, etc. I read a thread about substituting kevlar as skins and winglet attaching for a VEZ and got a lot of info there, mostly along the lines of, "don't substitute materials, the designer knew what they were doing." My reason for asking comes from reading the construction manual; the wing spar cap is S-glass yarn, while the canard is the flagged UNI. Second reason, I took a Sport-Air workshop, and for the canard/airfoil section we assembled in class, we used S-glass for the spar cap. Granted, this is a big deviation from the Rutan plans, but I found the S-glass easier to lay than the flagging I tried at home. So, again, my question would be yea or nay? Or, perhaps I already answered my own question...

Title: Re: Using S-glass roving as opposed to flagged UNI for canard cap?
Post by: srothert on February 09, 2013, 10:57:26 AM

Find a copy of the Roncz canard plans.  You will see in there that the canard spar caps are the same 3 inch wide E-glass roving tape, as used in the center section spar and the wings of the Long-Ez.

Maybe one of the Berkut guys can give the specifics on the graphite used for their spar caps.

Steve Rothert
Long-Ez N49SR
Albuquerque, NM

Title: Re: Using S-glass roving as opposed to flagged UNI for canard cap?
Post by: propblade on February 11, 2013, 10:04:17 PM

Excellent, thanks! 8)

Title: Re: Using S-glass roving as opposed to flagged UNI for canard cap?
Post by: go ez on March 04, 2013, 02:50:35 PM

I'd be careful about substituting key glass structural items (and particularly those in compression) - what are you hoping to gain?
And I'd keep away from kevlar on the VE wing as it is poor in compression and there is no spar from about 8" outboard of the wing mid span. Total reliance on the skin.
 :)