Tailwheel Springs

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New Sportsman tailwheel spring.
New Sportsman tailwheel spring.

I’ve never been entirely satisfied with the way the tailwheel leaf springs are secured to the tail cone, especially when banging them off of grapefruit-sized rocks on gravel bars. Almost all other bush-style aircraft use a bracket that clamps the spring set to the frame, so i set out to imitate this type of installation.

I cut a slot in the bottom of the fuselage to the exact dimensions of the spring width. I also had some custom springs made for my Sportsman that are shorter on the front end and longer on the tail end in order to lift the stabilizer higher with the goal of reducing the damage from rock spray on off-field landings.

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I added a small bulkhead just aft of bulkhead D for the forward spring attach bracket, but also laid up a 14- ply fiberglass pocket over the leaf springs. This thickness (or perhaps more) is necessary to react against the extreme loads encountered at times when the tail wheel smacks into large rocks as well.

At the aft end of the springs, I fabricated a bracket that captures the springs between two AN5 bolts that anchor to an aluminum bracket embedded on the inside of the tail cone ahead of bulkhead E. The bolts squeeze the bracket and springs upward against the fuselage. On initial evaluation, it appears to be much sturdier. Flight tests will prove it out one way or the other.

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Ted Setzer
Born Wichita Kansas Oct 02, 1953. (have a fascination with tornadoes) Private pilot SEL & Sea approx 3,000 hrs Co-founder of Stoddard-Hamilton Aircraft in 1979. Contributed developmentally toward all models of the Glasair, GlaStar and Sportsman in from 79' thru Oct. 2016 when I retired. Whew...38 years! Started construction of my own custom, lightweight Sportsman in 1999 from the basic kit. First flight of N11YM was Jan 2013. I love this plane and have tested three variations of taildragger main landing gear. Recently purchased a set of Clamar amphibious floats and can't wait to install them hopefully in 2018.