Hatz Biplane Association

Thanks for the feedback on the SS. I have the 4130 - I'll use it.

Stainless Steel is certainly a good material in some applications, but in the area that you want I wouldn't. Although stainless is a very dense tough material the properties of the metal are soft, and will bend. I've saw this happen on two (2) applications where someone had welded up out of stainless a landing gear jack pad such as used to jack up steel spring gear. The pad bowed when weight was applied and actually popped off the gear leg. I don't have a book in front of me discussing the tensile strength, but you can't go wrong with 4130.

For what its worth - I've researched in Tony Bingelis books and the EAA Welding Handbook and find that the hinges as described for the rudder are quite common on the tail surfaces (elev and rudder) of many airplanes, especially of the Hatz type (I.E. - Biplanes and other dirty "slow" aircraft)

While I agree that the hinges as described with the bronze bushings could be tighter and smoother, it appears the rudder hinge design is used on a number of aircraft elevators per design. Since they're already welded on, I think I will fly them unless I receive material evidence to the contrary.

I'm considering using stainless steel of the same dimension as called for in the 4130 for the tangs that attach the brace wires on the empennage. The SS will avoid painting/rust issues for the most part and will nicely match the flying wires which they are attached to.

Anyone know of any caveats with direct exchange of SS for 4130 in such an application requiring bending but no welding?

Jackal,

I'm probably not qualified to answer, but there is a lot more load on your elevators than on the rudder. You would want them tighter and smoother. I dis-assembled mine after 23 years and they were still nice and tight. I have a friend with a Great Lakes and his rudder has quite a bit of slop (to me) but it doesn't seem to hurt anything. Can't answer you about the travel right now. My tail feathers are still off the airplane.

Steve G

It was after welding my elevator hinges on that I noticed the NOTE: in the top left of page 7 indicating the elev hinges are 3/8 I.D. with bronze bushings, and not 3/8 x .065 bushing stock as on the rudder. I made my elev hinges the same as the rudder hinges. Is not what's good for the rudder good for the elevator? Yes, loss of pitch control usually hurts more than loss of yaw control........

Anyway, does anyone have any input on the reason for these hinges being different/experience with elev hinges built like the rudder hinges and still here to talk about it?

Just curious, what is the difference in the properties of 4130 tube and the bushing stock tubing. Wicks sells both and I used bushing stock when called for, but was just wondering the mechanics of it all.

While dealing with the empennage - What are good travel limits for the elevator? Maybe 35 degrees up and 25 down? Any suggestions??

Thanks,

-Jackal