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Drilling Replacement Torque Tubes

Stansuski

Member
Hello, I am going over a new to me RV-12, one of the many things I am correcting is the flaperon setup, to say it was not to spec.is an understatement, I have become intimately familiar with this one now :mad:. My current project is measuring all control linkages and I had to replace the mixer due to improper assembly ( long story), all control tubes are now exactly to spec. , since everything was wrong now that the mixer is correct and all other parts proper length as you can imagine the flaperons are out of sequence , I have new torque tubes but have original torque arms which means the original #30 holes have already been enlarged, I am looking for help in deciding the best way to drill new tubes using original arms, those of you that have done this could you please give me a heads up on the best way to do this and did you remove the tube/arm assembly to drill bottom holes or did you just drill all the way thru from top? I know this is a critical procedure and want to do it correctly.
Thanks in advance,
Stan
 
Stan-

If it were me, my first choice would be to start with new undrilled parts and set the flaperons for the proper 1/8" droop per the plans, then insert the .063 temporary spacer as shown in the plans and drill.

But if you don't want to order new torque arms, don't know how well the following will work in practice ... but, I guess the next best would be to set the flaperon droop per the plans, insert the temporary .063 spacer, then make a drill guide with a #30 hole in the center. The drill guide could be made from the smooth shank of a AN3 bolt long enough to hold onto. Chuck that into a lathe and drill a #30 hole through the center. Ideally, a curve the same diameter of the WD-1214 torque tube should be milled onto one end. The milled curve should sit perfectly on the WD-1214 ... this will allow the guide to set into the existing hole in the WD-1215 torque arm without flopping around so you can drill a nicely centered #30 hole into the WD-1214 torque tube. After that I would be tempted to use a 3/16" pilot point drill bit to drill to near final size then finish with a #12 as called for in the plans.

Below is a link to a method I used to set the flaperon droop:
http://www.dogaviation.com/2015/06/match-drilling-wd-1214-flaperon-torque.html

Perhaps others will have a better idea.
 
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I also had to redo mine and went with new torque arms and was happy with the result
Alan

Alan , so you replaced both torque tubes and torque arms and did standard installation per the K.A.I. ?.
Thanks,Stan
 
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Stan-

If it were me, my first choice would be to start with undrilled parts and set the flaperons for the proper 1/8" droop per the plans, then insert the .063 temporary spacer as shown in the plans and drill.

But if you don't want to order new parts, don't know how well the following will work in practice ... but, I guess the next best would be to set the flaperon droop per the plans, insert the temporary .063 spacer, then make a drill guide with a #30 hole in the center. The drill guide could be made from the smooth shank of a AN3 bolt long enough to hold onto. Chuck that into a lathe and drill a #30 hole through the center. Ideally, a curve the same diameter of the WD-1214 should be milled onto one end. The milled curve should sit perfectly on the WD-1214 ... this will allow the guide to set into the existing hole in the WD-1215 torque arm without flopping around so you can drill a nicely centered #30 hole into the WD-1214 torque tube. After that I would be tempted to use a 3/16" pilot point drill bit to drill to near final size then finish with a #12 as called for in the plans.

Below is a link to a method I used to set the flaperon droop:
http://www.dogaviation.com/2015/06/match-drilling-wd-1214-flaperon-torque.html

Perhaps others will have a better idea.

John, thanks for your reply, I know how critical this matching is and may order 2 new torque arms unless I can come up with an easy accurate solution as I have no lathe, I have followed you build and it looks great.
Thanks, Stan
 
I have no lathe

Don't forget to ask friends who may have access to a machine shop or talk to local EAA members. Making a small guide like that is something that can be done in a machine shop in 15 minutes for a lunch or $20.
 
yes I replaced both.
an A&P friend who also is a machinist thought it ewzas the best way.
Alan
 
I have decided to replace both the torque tubes and the torque arms, not able to do until end of week now as Van’s sent me 2 left torque tubes as one was mis labeled right and it was really a left, I will contact them in the morning, oh well thanks for your reply’s.
Thanks, Stan
 
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