Re: Runway excursion - canard bent

David J. Gall


I like your attitude about finding and addressing failure modes before flight. I think that retiring your canard is a wise choice, whether you replace it with another GU canard or convert to an LS-1 canard. If you go with the LS-1, be sure to install all the elevator balance weights per the QPC change notices, and be sure to have sparrow strainers installed before attempting flight.

Regarding your tailwheel steering circuit: The torsional flexibility of the rudder pedals has already been mentioned, so please add my vote to eliminating the right-side rudder cable in favor of a cable through the center console for a more-direct connection to the pilot's right foot.

Also, please consider completing the "Jim-Bob six-pack" by adding a belcrank in the tailcone from which the separate rudder and tailwheel control cables should emanate, and adding springs into the tailwheel control cables per standard taildragger practice. The belcrank allows the tailwheel to have somewhat less angular deflection than the rudder and the springs allow the tailwheel to respond to a force rather than a displacement. Both will help to reduce tailwheel skidding and result in better tailwheel authority.

Finally, looking over your website, I noticed that your steel mixture control full-rich spring is riding against the aluminum oil cooler. The vibration of this spring will cause it to wear through the oil cooler.

Just my humble opinion,

David J. Gall

(Yes, of course: Do the main wheel alignment.)

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