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  #191  
Old 10-04-2015, 09:05 PM
David Paule David Paule is offline
 
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The third left aileron continues. When those lightening holes are drilled, the spar warps just a bit. The clecos in the previously-drilled holes through the spar flange and the skin hold that flange nicely in position, and I clamped a straight piece of steel angle to the spar web to hold the bottom flange relatively straight. Then I drilled the holes though the bottom skin and the spar flange.



The leading edge needed a bit more bending around the pipe. To do that, I wanted something a bit smaller diameter than the pipe, so I used the stock for the aileron pushrods. I taped it to the skin and massaged the bend and this worked nicely. Ideally, I should have done this before drilling the bottom flange holes but it turned out okay. It did leave a small gap which the rivets pulled down nicely.



Shortly it was time to rivet the top flange of the spar to the skin. I'd previously done this by riveting with the gun's set supported by a wooden batten and using an "L"shaped bucking bar to get in to the shop side of the rivets as shown in post #157. The constraints can be seen here.



Look for the skin overlap on the right; that what I needed to work though, with that overlap opened up and riveting the flange on the left. I was able to do one aileron successfully that way all by myself. I ruined one more by myself and one additional one with the help of a friend - that .016 skin is very fragile.

This time I decided to see if perhaps I could back-rivet it. As you might predict, the straight back riveting set wouldn't get to the flange. I didn't find an offset back riveting tool so I started looking for something, anything, that might do the job. What I found was a "C" tool. This nifty device is driven directly by the rivet gun as shown, and has a 3/16" hole in the other end for any rivet or dimpling set you might wish.



I bought this one from The Yard Store.

For what it's worth, the rivet set at the left end is 1/2" long and 1/2" diameter. The box-end wrench is a cheap HF one, 1/2" size.

It still took some care, since the access was awkward and it took two hands: one on the gun and the other pressing the spar flange to the skin with the box-end wrench. The box-end wrench substituted for the plastic spring-loaded tube usually found on back-rivet sets.

I quickly found that the 2x gun, pictured, which I usually use for the 3/32" rivets, was not powerful enough to drive these rivets. I had to use a 3x gun and crank the air pressure up to about 43 or 44 psi. Then it worked okay. That gave me a nice smoothly-driven row of rivets.

Success.

Worth mentioning but not pictured, sorry, is that on this aileron I used shims between the spar web and the nose rivet back flange. Both sides use .120" thick shims, and the need for shims on the upper or lower flanges was much reduced.

Dave
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  #192  
Old 10-04-2015, 09:17 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
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Default New tool

Now I see how that new set works. Nice job Dave.
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I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
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  #193  
Old 11-01-2015, 09:18 PM
David Paule David Paule is offline
 
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Location: Boulder, CO
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I'd saved the wing crate with the idea that it would be useful for a wing cradle. After struggling with various concepts for hanging the wing frames on the wing jig with the leading edge down so that I could hang the ailerons and flaps, I finally realized that it would be much easier to build the cradle now.



Since I felt that it would be best to lower the leading edge below the side of the crate, I cut some wing-clearance openings in the cradle. Then the center portion of the carpet support was a bit wobbly so I added a strut to other end, which was braced better.



A friend helped me move the wings to the cradle. They don't weigh all that much and it wasn't too hard. Good thing there's no fuel in the tanks. We walked the wings out to the driveway, one at a time, rotated them so that the south end became the new north end, and then rolled the loaded cradle back into the shop, where it nests nicely in between the legs of the jig. Rob Leary helped me move these.



After adding a few battens to the wing frame to support the right aileron and putting the aileron side of the hinges on the wing's hinges, I measured the distance from the rear spar to the trailing edge of the aileron. You can imagine my astonishment when it was 13.00 inches, exactly what the plans specify. This was so unexpected that I immediately double-checked my measurement and confirmed it. Got lucky there.

Next was adjusting the spanwise position, set with a measurement at the tip. Then I installed the bottom half of the airfoil cut-out to set the up/down position. This was the piece that helped me position the hinge on the rear spar.



Here's where that cut-out came from. I used this to locate the aileron hinge holes on the wing. Note the hinge locator fitting.



This is a closer look at the hinge locator fitting. The markings for the rear spar were taken directly from the rear spar, so that provided me with a fore-aft relationship, and the horizontal line that runs through the fitting is 3.0 inches below the chord line and parallel to it; this gave me a vertical reference. I had to draw that before cutting the middle out of the jig, of course, because the chord line that I'd drawn on the plywood got cut out.



Haven't tried on the left aileron yet.

Dave
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  #194  
Old 11-02-2015, 03:27 PM
David Paule David Paule is offline
 
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I don't think I posted this photo before. The photo was taken a year ago to show any prospective inspectors or buyers that yes, indeed, I installed anti-rotation parts on the fuel lines.

It shows the anti-rotation devices that I installed on the fuel lines. Note that no safety wire is needed, and I didn't bother to drill any holes for it. Yes, if I ever need to remove the fuel pickup line I'll have to unrivet the brackets (nutplates could have been used), but I decided that was unlikely.



Putting the bracket on the nut blocked two rotational degrees of freedom at once: the nut can't unscrew, and the fuel pickup line can't rotate in its hole in the access port.

The one on the left is a bit bulkier than I like but that's what it took. Keen weight-conscious readers might observe that I could have lightened these parts, and I agree. I should have.

Dave
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  #195  
Old 11-03-2015, 06:03 PM
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jeffw@sc47 jeffw@sc47 is offline
 
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Location: Simpsonville, SC (SC47)
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Default anti-rotation HOW?

enlarged picture in PS and searched google for "anti-rotation device" to figure out how these prevent rotation > no figure out or findy.

explain the works of an anti-rotation device as your 90 degree bent plates must do.
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  #196  
Old 11-03-2015, 07:22 PM
jarhead jarhead is offline
 
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Quote:
Originally Posted by jeffw@sc47 View Post
explain the works of an anti-rotation device as your 90 degree bent plates must do.
Think of this anti-rotation plate as a very thin box-end wrench, that is permanently secured to the access cover.
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  #197  
Old 11-03-2015, 08:35 PM
David Paule David Paule is offline
 
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Here's what I mean by two degrees of freedom:



This simple line drawing shows the access plate and the elbow that's Pro-Sealed to it. Then the red arrow shows the first axis of rotation; the elbow can rotate in its hole. This is one degree of freedom.

The second axis of rotation, the second degree of freedom, is the nut that's threaded on the end of the elbow to secure the pickup tube. I didn't draw the nut.

You can see that a single wrench placed on the blue circle in the right position can twist both the nut in the blue direction and the elbow in the red direction. That's all the anti-rotation fittings, are, just simple 12-sided box wrenches riveted to the plates to prevent these from moving, as Ken said.

This complies with the intent of Van's service bulletin sb06-2-23.pdf. I used a part that Van's sells, but I forgot the part number. It has four of the fittings in one piece and we have to cut the separate pieces apart. The 12-sided cut-out is pre-stamped, ready to slip over the nut.

Hope this isn't too confusing....

Dave

Last edited by David Paule : 11-03-2015 at 09:52 PM. Reason: Simplify the explanation
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  #198  
Old 11-09-2015, 07:16 PM
David Paule David Paule is offline
 
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The ailerons are hung, if you can call a couple clecos at each hinge "hung." I haven't drilled the holes out for bolts yet. They check out with a straight edge lining up the tooling holes as well as fitting my shape jig.



They have ample free movement. Another thing I haven't added yet are the aileron gap fairings. While that's the logical next step, I thought that I'd have a look at the flap mounting process before that. I don't imagine that there's interference between them but it's worth a check, so that's next.

Since I was out at the hangar the other day, I picked up the right wing tip and brought it home. It's white fiberglass. I made a trial fit on the right wing just to have an idea how it fits and what I'll be in for. Since the empennage tips fit so poorly I wasn't expecting much. In fact, that's why I only brought one of them, figuring that would be bad enough, plus I really didn't expect the left wing to be ready for a fit so soon..

You can imagine my surprise when the tip fit very well indeed. Of course it'll need a bit of trimming to clear the aileron hinge and that sort of thing, to be expected, but aside from that it fits great.



This is another thing that I'll postpone. There will be considerably more fiberglass work later and I'll do it all them, just to have fresh resins.



Dave
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  #199  
Old 11-16-2015, 09:09 PM
David Paule David Paule is offline
 
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I'd previously gotten the flaps to the point that except for the hinges, they were ready to be deburred, dimpled and riveted together. With the ailerons on, it was time to locate the hinge, the hinge brace and do some more drilling.

The flap brace notch for the rear spar inboard fitting isn't shown all that well on SK 28. When I placed the brace on the spar there were some questions. Andy Hill suggested having a look at the RV-4 and RV-8 plans and those showed a substantial notch in the brace.



I drilled the lightening holes and figured out a suitable spot for the cut-out and here's what it looks like at the inboard end.



With that figured out, I set the flap in position on the wing frame and shimmed it to the bottom skin's aft edge until the trailing edge matched the aileron's. Then I measured the shims. This let me position the flap side of the hinge on the flap and drill them together in my vee jig to keep the flap from twisting. I used both sections of hinge there to ensure straightness.

Locating and drilling the hinge fore-aft on the bottom skin was more tricky. Shimming the flap into position wasn't hard but if I tried to drill the skin, brace and hinge together, the hinge would simply fold out of the way. There was no access except at the inboard end. And due to possible straightening of the parts as I brought them together, and wanting to maintain the 1/4" gap to the aileron, I wanted to drill from outboard to inboard.

First, I clamped it all together with the hinge held in the correct place, and located the rivet line. Then I removed the flap brace and hinge and drilled through the skin. Clamping the brace and hinge back together with the skin, I drilled the holes using the skin as a guide. The photo shows the inboard and outboard holes drilled and the piece of angle I used per David Howe's suggestion, to ensure straightness.



The remaining holes were indeed drilled outboard to inboard, clecoing as I went, so that there was enough stiffness from the cleco in the previous hole to allow me to drill the next hole. As I got close to that one inboard-most hole, I removed its cleco so it could float. But I'd done it right and it didn't shift.

Here's the right hand flap clecoed in position with the aileron on the wing. It's ready to prep and rivet.



That's the right-hand flap. Now working on the left-hand flap.

Dave
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  #200  
Old 11-21-2015, 08:10 PM
David Paule David Paule is offline
 
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Here's a photo showing the left flap being drilled for the hinge.



Since these holes also connect the skin to the spar flange, I drilled it in the Vee jig.

A bit more work and the left flap, like the right, is now drilled to the wing. At this point, though, both flaps need to be deburred, dimpled, countersunk, etc., and then riveted up. There's some work left.



With the flaps off and the flap braces drilled to the skin but not the spar, I removed both ailerons and started work on the aileron gap fairing. The plans call for an RV-3B part, W-323, and Randy Levold recommended the W-824 gap fairing instead. Van's sold me the W-724 which you see below.



While this appears to simplify things, and it does, there are a few bits to consider. First, it's about 6" too long so you'll have to trim one end. Actually you'll have to trim both ends somewhat. Once that's done, it will fit reasonably well, except that a few of the pre-punched rivet holes are in exactly the wrong places. And a few more are almost in the wrong places. Still, it does simplify things and I don't suppose it weighs any more. It might weigh less.

Since its shape is different than the W-323 fairing that's designed for the plane, when I got the fairing clamped in place, I hung the aileron back on and checked. There's ample clearance.

Here's the W-323 part for reference. Notice the nice curve and the flange that's hidden by that curve.



One thing about the W-323 part, is that you'll probably need to trim the ends to fit around the hinges. I'm not sure about that since I haven't seen one, but I suspect that would be necessary.

I realized that I had enough of the electrical parts, things like the alternator, regulator and solenoids, plus a few other parts and have identified some of the others, so that I could start on the electrical diagram. I'm doing it by systems, and now have a draft schematic of the power/starter system and another of the audio system.

I'm following the schematics in "The Aeroelectric Connection" and on the www.bandc.biz site for the sort of operation I have in mind. These are being tweaked to fit the particular components that I'm accumulating or have chosen. I'm drawing this on a Mac graphics program called "Graphics." It used to be called iDraw but they changed its name. This is a general-purpose drawing (not CAD) program, not a schematic program, and for me that's okay. I can draw something once and copy it all I want and I already know how to use the program.

Right now these schematics are relatively immature. After they grow up some and when I work more on the systems than the airframe, I'll present them.

Dave
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