Thanks Jeff(and Mike T & Gary Sack), With metallurgy not being my subject, I didn't realise that existing springs could be bent, drilled and cut etc so I think I'll start looking for an existing that can be modified to fit.
Thanks again. ________________________________________ From: KRnet [krnet-boun...@list.krnet.org] on behalf of Jeff Scott via KRnet [krnet@list.krnet.org] Sent: 11 February 2019 16:00 To: krnet@list.krnet.org Cc: Jeff Scott Subject: Re: KR> Tail Wheel Springs (but aluminium) Actually, once you get past the cost, Titanium makes for very nice landing gear. I have a friend that replaced the bungee main gear on his homebuilt plane with Titanium gear legs that he designed and built. They were aerodynamically much cleaner than his bungee gear with braces and bungees. Corrosion also isn't much of a player with titanium. However, it is difficult to bend to shape, and difficult to cut or grind. Some aircraft do have aluminum gear legs, so clearly it can be engineered to be used as a spring. However, you have to be really careful about overloading aluminum. Aluminum doesn't really display fatigue so much as it will simply fail once it has reached it's fatigue limit. Fiberglass and carbon fiber also make nice springs if you want to spend some time laying up unidirectional cloth, although best results will be done using vacuum bagging and prepreg materials. Solid rods are also a tail spring option as found on the Sonex and RV series aircraft. The RV series uses a 4130 tapered rod while Sonex uses a straight Titanium rod. There's a reason why the vast majority of taildraggers have steel leaf springs. However, if you have a unique situation where you really need to reduce every last ounce of material at the tail, then there are other viable options. Probably the lightest, and lowest profile (nice for a KR) would be the Sonex Titanium rod, which also is relatively inexpensive at $80. The Sonex non-swiveling tailwheel would also be very light weight, although I would recommend using the Aviation Products Inc full swivel tailwheel. They have them in both hard rubber 4" and soft semi-pneumatic 6" with single or double fork units to match any tail spring assembly mounted at almost any angle. For my KR, I bought a simple single leaf spring from Aircraft Spruce. I found that spring to be a bit too soft, so took one backing leaf from a Cessna 140 spring set, cold hammered it to match the shape of the main spring, then torch heated it cherry red and quenched in used motor oil to harden it in it's new shape. That configuration has served me well for 1200 hours now. -Jeff Scott Cherokee Village, AR > Subject: Re: KR> Tail Wheel Springs (but aluminium) > > Forgetting about the $$ problem, how about titanium? Does that have > steel-like springiness? > > Mike Taglieri > _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
