Re: Q2 LS1 Carbon spar?


David J. Gall
 

Paul B.,


Please stop implying that the Waddelow canard is a stock LS-1 canard minus the carbon spars. Further, please stop implying that such a canard would be airworthy, regardless of whether Mark Waddelow had anything to do with it. Someone could die following this "advice."


Mark Waddelow did an engineering analysis of the original GU canard and reported to the Quickie Builders Association that he believed that the GU canard layup schedule was inadequate for the design. He recommended a revised layup schedule. He also designed a 236-inch span canard to replace the 200-inch "factory" unit. He died in an unrelated incident before building (completing) either.


I am not aware that Mark Waddelow ever made mention of the LS-1 canard or the factory LS-1 spars before his untimely death, but I am certain that if he had undertaken an engineering analysis of the LS-1 canard in a Tri-Q he would not have drawn the conclusion you assert. Even just a cursory glance at the layup schedule for the LS-1 canard makes it glaringly evident that the SINGLE spanwise UNI ply (and two +-45° UNI plies) would be totally inadequate for flight loads of a Tri-Q.


Casual inspection of the Tr-Q conversion plans written by Scott Swing and available on Quickheads.com (thanks to Dan Yager) supports that conclusion by revealing that the Tri-Q GU canard conversion calls for no less than 10 spanwise plies of UNI to repair the necessary cut in the GU canard needed to remove the anhedral. Likewise, the Tr-Q conversion plans call for exact duplication of the original factory layup schedule (including retaining the carbon spar) to repair the cut to the LS-1 canard required in order to remove the anhedral.


Any other "reduction" of structure, such as leaving out the spars, would be foolhardy.


Generally, root bending moments are the controlling factor in wing (canard) structural design. The bending moment at the root of the Q2/Q200 canard is approximately the same for flight loads (4g) as it is for ground loads, hence, the structure must be the same regardless of whether or not it is "subject to landing loads."


Perhaps you have confused the Waddelow canard with the Weishaar LS-1 canard which does not, in fact, use the factory-supplied round, tapered carbon spars. If so, then be advised that the Weishaar canard does, indeed, use a carbon spar, just not the round carbon spars from the Quickie factory. The Weishaar LS-1 canard does not "dispense with" the factory carbon spar because the Weishaar LS-1 canard was actually designed before the factory LS-1 canard and it's round carbon spars. The Weishaar canard has a hand-layup rectangular cross-section carbon spar.


David J. Gall

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