A forum about all aspects of the construction and maintenance of the Billy Dawson inspired modified Hatz Classic biplane. Here is the place to ask your questions and get the answers from the real experts.
I was going to start on the torque tube but run into a problem with the AN4-10A bolt shown on the plans. See below. The first image is a copy of the plans. The second image is my drafting. I'm using rod end bearings so the drawing is slightly different. In any case, I don't think the AN4-10A bolt can fit inside the 1.5" torque tube if the control stick is in the middle. The plans make it look like it does but it's not drawn correctly.
One way to get around it is offset the control stick. I'm using 3/4" tubing so it would work for me. How did you guys make it work?
Mine is different (modified CB-1) but perhaps you could solve the interference by using a locking shear nut instead of the full-size locking nut. The axial loads would be insignificant and the shear nut would be plenty strong I think. You might need to cut down the bolt length slightly (you could paint or re-cad the end) or use a washer under the bolt head if there is enough shaft length for the bearing surface.
Hi Murray, I just finish modifying my CB-1 project, like Paul, last week. I also used ball joint ends and used shear bolts and thin castle nuts to get clearance. The thin slotted head on the bolt and the thin castle nut with a thin washer with cotter pin gave me the needed clearance. They make thinner type ball joint ends also if needed. Good luck. Ray B
My 2 cents worth would be if I offset the stick to one side, my OCD would kick in and I'd be flying around in a circle trying to get the stick back in the center!
That is one area that I thought was a little shaky. If the nut starts to back off even a little the bolt head will bind the stick. once it comes out of the tube it may not let the stick move in one direction. I used a thin castle nut and a cotter pin rather than a lock nut.
Ed White
HC 154
"In life 10% wrong is failure, in school it's an A"
JBMoore wrote:My 2 cents worth would be if I offset the stick to one side, my OCD would kick in and I'd be flying around in a circle trying to get the stick back in the center!
Jeff Moore
Good for staying in the pattern!
I like the idea of the smaller nut, whether it be a castle nut or locking shear nut. I thought about a shorter bolt but then it gets into the problem of the grip being too short and the connection riding on the threads. I didn't think about cutting the bolt shorter. Right now I can't think of any reason that breaks any common sense rules.
Thanks guys. I'm going to toss those ideas around and see if I can make one work for me.
Hi, I used a thin castellated nut with the nylon grip feature. I got them fro A/C Spruce. It is a tight fit. I also opened up my torque tubes on the bottom as well....didn't really need to, just made it easier to get to the connections some. I used a rod end for the front stick connection also, to allow for adjustment, just because I NEVER seem to cut things exactly as long as they should be.
I redrafted using the AN364 nut. It works. Just have to cut the end of the bolt off.
The grip for the AN4-10A bolt is 9/16" which is all needed for the connection so a shorter bolt won't work.
TorqueTubeAN364.PNG (50.6 KiB) Viewed 4224 times
PS: I had the thickness of the AN365 drafted slightly too large. The specs for the bolts are everywhere. But try and find the specs for the nuts. I finally founds a couple sources. One is the military spec for the MS20365. The other was for the AN364/365 series. Both say 0.312" for the AN365. The AN364 is 0.203 thick". Both include the nylon lock.
I did a few redesigns of the torque tube. One is adding rod end bearings for the push tubes. The other is the adding bearing stock RV style to the control stick pivot bearing. I used the same thing for the aileron bell crank. I think it makes it a lot easier to build and the bolt can be torqued the same as a rod end bearing. The action is RV style smooth.
