Wednesday, November 4, 2009

More Flettner work: yet one more job saved or created

After gracing my family with my cheerful, gregarious presence for the last one and a half evenings, it was back to work on the Flettner tab tonight. Having resolved the mystery of the too-small holes in the rib flanges to my satisfaction, I went ahead and drilled them out with the #30 to make them big enough to take a blind rivet. Having done that, they all had to be removed for deburring.

Deburring the inside of the tiny little rib flanges can't be done with the normal power-driven deburr bit. Rather, I have to use this tool:



I don't like the looks of it. It looks too much like a dental tool or an instrument of torture. Granted, the distinction between the two is almost vanishingly subtle. With this tool, though, I can reach through the top of the hole and deburr the other side.

At this point, Van's says to rivet the top of the skin to the top of the ribs. If you read ahead, the step after that has you riveting in the control horn. Some folks on the Vans Air Force site said that it might be easier to rivet the control horn in place and then rivet down the top skin. I clecoed everything together and practiced both methods and found that the Van's method worked best for me. Differences of technique such as this with different builders more often than not come down to slight differences in the tools being used. With the rivet squeezer and rivet pullers that I have, the Van's method provided easier access, although I did end up bending one of the rib flanges. That was easy to bend back into shape, though. I went ahead and riveted the top skin to the ribs:



Here's the "raw" control horn:



It gets riveted in with solid flush rivets, so it needs to be countersunk:



There's nothing prettier than a countersunk hole, in my opinion. The machined look of it just makes it look more sophisticated somehow.

Here it is clecoed into place:



And here I am reaching back inside there to squeeze the rivets:



All done:





Your eyes didn't deceive you in the pictures if you noticed that one of the pictures shows a control horn labeled 'L' and one laebled 'R': there are two tabs, actually, a left and a right.

Here they are in their relative positions as they will be installed on the airplane:



Tomorrow night I will fabricate and rivet on the hinge strip that will attach the Flettner tabs to the horizontal stabilator. After that it's a simple matter of riveting the bottom skin to the ribs.

3 comments:

Anonymous said...

Dave,

Nice work on the tail feathers. Any comments on the use of pulled rivets vs. solid rivets?

Love your blog. Read it all the time.

Gene Spooner
Greensboro, NC

GregoryJ said...

Dave,
I think I'm gonna have to disagree with you on the machine counter-sunk comment. I'd rather see one dimpled because all of the material is still there. It is pretty though.

DaveG said...

Gene -

Pulled rivets rock! No need for a riveting partner and very low risk of driving one poorly. Also, one size fits all! I think blind rivets could make or break the ability to finish a kit in many cases.

Post a Comment