Riveted the inboard forward fold ribs and fixed the aileron paddle. Can't find the last four fix nuts.
Showing posts with label aileron paddles. Show all posts
Showing posts with label aileron paddles. Show all posts
Thursday, March 26, 2015
Wednesday, March 18, 2015
Saturday, January 04, 2014
Aileron paddles (finished)
These paddles needed lots of modifications. The Aurora bearings also must be installed, and Kerry sent a mail late last night (Norway time) that this will be a very tight fit, possibly moving the hole for the bolt longer out. So I took one bearing just to see how it fitted.
The one and only paddle that was according to plans, looked like it would fit exactly, but the one with the hole filled would have no chance of fitting. So I drilled out the rivet, countersunk also on the other side, and riveted a new one in. Then I filed off the excess and had a nice "foot" with two perfectly flush surfaces.
To be sure the bearing would go clear of the foot, I dremeled the hole a bit oval, then drilled #13 and reamed up to #12 for the AN-3 bolt. In the end I had a hole that was offset enough to give a clearance of about 1 mm (checked with bushing and AN bolt into the bearing). Finally a set of paddles that fits and is according to plans.
The one and only paddle that was according to plans, looked like it would fit exactly, but the one with the hole filled would have no chance of fitting. So I drilled out the rivet, countersunk also on the other side, and riveted a new one in. Then I filed off the excess and had a nice "foot" with two perfectly flush surfaces.
To be sure the bearing would go clear of the foot, I dremeled the hole a bit oval, then drilled #13 and reamed up to #12 for the AN-3 bolt. In the end I had a hole that was offset enough to give a clearance of about 1 mm (checked with bushing and AN bolt into the bearing). Finally a set of paddles that fits and is according to plans.
Aileron paddles
According to Kerry the drawings are correct and should be followed regarding the paddles. OK, this means that only one single paddle of the four are correct, and that is the left hand inboard. The ones marked outboard paddles has a hole in the "foot" that is not supposed to be there. The right inboard paddle is a copy of the left, and therefore has the hole for the aileron push rod on the wrong side (when on mounted on the right hand side). No big deal, I think it will work no matter how they are mounted as long as the hole for the push rod is correct on both sides, and the extra holes on the "feet" are filled up. Anyway, I shuffled the inboard and outboard paddles so they will be 100% according to the drawings. This means I have to make one new hole and fill up two other. The holes in the feet are 1/8, and I meant to use a flush 1/8 solid rivet, but I managed to countersink a bit too much, so I went up to 5/32 and countersunk a bit too little so I could file them 100% flush when set.
I don't really like the mechanism with a steel set screw in the aluminium paddles. A little moist and salt and this is bound to corrode both at the threads of the set screw and in particular at the contact points between the tip of the set screw and the paddle, and there really is no good way to prevent this. Nothing dangerous, but I suspect these will need to be adjusted often to keep the mechanism nice and tight. Duralac can't be used here as it hardens too much (it is meant for permanent fasteners). A much better design would have been the paddles also were made of steel. This way the steel and aluminium could be insulated at the rivet joints which is perfectly doable.
I don't really like the mechanism with a steel set screw in the aluminium paddles. A little moist and salt and this is bound to corrode both at the threads of the set screw and in particular at the contact points between the tip of the set screw and the paddle, and there really is no good way to prevent this. Nothing dangerous, but I suspect these will need to be adjusted often to keep the mechanism nice and tight. Duralac can't be used here as it hardens too much (it is meant for permanent fasteners). A much better design would have been the paddles also were made of steel. This way the steel and aluminium could be insulated at the rivet joints which is perfectly doable.
Thursday, January 02, 2014
Aileron paddles and mechanism
I need more clamps to be able to drill all the 1/8 holes on the spars for the outer ribs without getting burrs in between the already riveted parts on the spar.
So I started on the aileron paddle mechanism for the folding of the wings. The 4 paddle blocks shall have two bearings each. The holes for these bearings are not honed or reamed to correct size, but are approximately 4-8 hundreds of a mm too small. I should have a reamer to do this, but a reamer this size costs 150 $. The drawings say use a reamer or sand it slightly. So I sanded and sanded and sanded... which was very fiddly because the hole is only approx 17.45 mm. Eventually I got them up to 17.5 mm, the bearings I measured to 15.52 mm, so this should be a nice fit. Here I really think Sonex should have reamed this part up to correct size. The block itself is (as all machined angle components) are really first class pieces of machined aluminium, and a press fit bearing is a close tolerance fit that requires reaming. Manual sanding and measuring and trying the pieces will do, but the amount of work is at least a factor 1000 compared to reaming. I thought about simply heating the blocks to let the temperature increase the holes, but Kerry (Sonex) said that heating should absolutely NOT be done, because the bearings will not stand the heat.
For the paddle mechanism, the drawings and the machined angled paddles does not add up at all. The machined angled parts have two identical inner paddles and two identical outer paddles while the drawings call for different LH/RH outer paddles and different LH/RH inner paddles. Very confusing, but both ways will work even though the end result will be different. There were also lots of trimming to be done on the already machined mating ribs to make the paddles fit.
So I started on the aileron paddle mechanism for the folding of the wings. The 4 paddle blocks shall have two bearings each. The holes for these bearings are not honed or reamed to correct size, but are approximately 4-8 hundreds of a mm too small. I should have a reamer to do this, but a reamer this size costs 150 $. The drawings say use a reamer or sand it slightly. So I sanded and sanded and sanded... which was very fiddly because the hole is only approx 17.45 mm. Eventually I got them up to 17.5 mm, the bearings I measured to 15.52 mm, so this should be a nice fit. Here I really think Sonex should have reamed this part up to correct size. The block itself is (as all machined angle components) are really first class pieces of machined aluminium, and a press fit bearing is a close tolerance fit that requires reaming. Manual sanding and measuring and trying the pieces will do, but the amount of work is at least a factor 1000 compared to reaming. I thought about simply heating the blocks to let the temperature increase the holes, but Kerry (Sonex) said that heating should absolutely NOT be done, because the bearings will not stand the heat.
For the paddle mechanism, the drawings and the machined angled paddles does not add up at all. The machined angled parts have two identical inner paddles and two identical outer paddles while the drawings call for different LH/RH outer paddles and different LH/RH inner paddles. Very confusing, but both ways will work even though the end result will be different. There were also lots of trimming to be done on the already machined mating ribs to make the paddles fit.
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