Compression tube #2 location

[Bitshifter]

Rick,
My wings are now finished and I ended up with the first and second compression struts at 2", the rest at the plans dimension. I might be looking at something wrong but I could see no way that the aileron bell crank would clear the wing fabric at 1.75. I also had to change the bell crank bushings from the plans dimension. It does bother me that no one else has replied with this same problem. I have some pictures on my site in the bottom wings section that attempt to show the problem.

Ed
Hatz, #154

[HC85]

Hi Ed, Thank you for responding to my question! I will set mine up the same, because I agree thinking, no way the cranks attach bolts will clear, even if you “shave” the tube bushings down to just above the weld lines. I “lurk” on your web site very often, and have found it to be very useful. Thank you for posting all that information! I'm sure that I will have to come to you for more info moving forward.
Thanks again,
Rick

[jwhanson]

We inserted the bolts from the bottom and used a castle nut and cotter pin and there was no contact with the fabric.
John Hanson

[HC85]

Thanks John, as that at a height of 1.75 or 2.0''?

I have your photo CD, and it is VERY useful! I highly recommend your CD to anyone interested in building the Classic, or in the process of building the Classic. I don't want to change the subject, but I will be asking about how you made the carburetor "airbox" ? soon, and engine your mount dimensions,,,I don't have any with my drawing set. I am headed to Brodhead this weekend, and hope that it is not rained out, and that there are classic builders in attendance! Lots of questions to be discussed!

Thx, Rick

[dougm]

I am headed to Brodhead this weekend, and hope that it is not rained out, and that there are classic builders in attendance! Lots of questions to be discussed!

Thx, Rick

I'll be there.

[HC85]

Great! I'm looking forward to the event!

[mmarien]

I'm thinking about starting the bottom wings and reviewed this post again. From the description of the bell crank idler on drawing 05 the distance from the center of the compression tube to the bottom of the idler is 1.875". Add the bushing and bolt head and it's about 2.125". If the compression tube is at 1.75 plus the 1/4" capstrip, there is only 2.0" clearance from the center of the compression tube to the fabric.

The plans don't have a dimension for this compression tube but the solution mentioned here is to put the compression tube at 2.0" from the bottom of the spar. The other would be to redesign the bell crank. I was thinking of using a bell crank bearing. The thickness is 0.625 which is half the thickness of the plan design. That would fit with the compression tube at 1.75"

So the questions is, does the 2.0" location of the compression tube cause the drag/antidrag wire to interfere with the cross pieces in the ribs or is it because of the different stationing for the compression tubes that causes the problem? The drag/antidrag wires in my top wings are close but there is no conflict with the ribs.

[HC85]

What I ended up doing is to place all the parts in position, without committing the drilling of the compression strut tube mount bolts.

Once I liked the position of the compression tube, with the bell cranks installed ( bell cranks built per plans) I drilled the holes for the compression tubes. I didn't pay much attention to the lengths of the bell crank bushings on the plans because they are just wrong. Only the diameter was right if I remember. I just made it all to fit.

I also remember for the bell crank mount bushing located on the compression tube, I made it shorter than the plans for maximum clearance allowance. I left just enough material on the comp tube bushing, for it to be a bushing.

I had a couple ribs interfere with drag/antidrug wires on the bottom wing, but not the upper wing. It was not because of the aileron linkage, but because I didn't pay enough attention to rib location prior to gluing them in position. Some of them would be better off not being exactly at 12 inch center to center intervals. I think I saw "approx." on the plans...... later someplace If I were to do it over again, I would leave all the ribs free to move until ALL of the goodies inside were located and clearanced as needed.

Rick

[mmarien]

Thanks Rick. I like the suggestion to put it all together before gluing and drilling. I think I'll do that.

I did come up with a redesigned aileron idler. A few things. It has no welding. Two pieces are riveted to a bell crank bearing that can be purchased. The bearing should have less friction then the bushing. It thinner so compression tube #2 can stay at 1.75" from the bottom of the spar. The brace can be put next to the idler under the compression tube to lend support closer to the pivot point. The bolt holding the idler on can be torqued with a nylon lock nut so the idler is more secure and should have less play.

Aileron Idler Bellcrank.png

[HC85]

Nice!