RV-3B Dave's in Colorado

[David Paule]

Van's made my WD-306 Flap Brackets to the plans. I checked. They are fabricated on Drawing 30 and installed on Drawing 9. If you're scratch-building, don't make them to the plans - make them to fit. They fit inside the FL-303 Flap Ribs.

This shows the trim line that I need to cut in the .040 4130 steel.



Drilled and deburred and primed the spars and doublers together but that's about all I did today.

Dave

[David Paule]

I've been busy lately and haven't worked much on the project. But it's not been a total loss. The flaps are ready for the deburring and dimpling, or will be after I install the hinges. And that's awaiting the aileron hinge installation, and then installing the ailerons, so that I'll know where the flaps fit.

The hinges are coming but I don't have photos yet. So here for your enjoyment, is a look at disassembled flaps and some ailerons at the bottom of the pile.



Dave

[ijustwannafly]

Looking good dave! Keep it up!

[David Paule]

I riveted the aileron hinges to the wings. Here's one of them.



For some reason that I can't figure out, the left wing was considerably more difficult than the right wing to rivet. The pieces fit as well, access was as good, the lighting wasn't any worse and both the inboard and outboard hinges took much longer on the left than the right.

But they're on.

That black tape is there to remind me that the pushrod passes that way.

I've started making the stiffeners for my third left aileron. You might recollect that I just replaced the original due to some dents that it had accumulated. A good look at the replacement shows that it had a similar issue. About when I get the stiffeners finished, the rest of this aileron will be delivered.

Hope this one is better.

Dave

[David Paule]

Recently I had a couple requests for details of my wing or empennage jig. Since the wing jig could be made into an empennage jig, here's how it's built.

Make two of these end frames. The wood doesn't have to be straight - but it MUST not be twisted.

Make the corner pieces like I've drawn, not like I've built. I screwed up one set. I used 1/2" thick cabinet plywood, the many-layered stuff.



Here's the whole assembly. The corner braces are reasonably large L-shaped pieces from Home Depot, screwed to the frames and the top cross-pieces.

Missing dimension: The frames have a clear space between the uprights. The gap's 101 inches wide.



This photo shows the end brace that's essential. Don't neglect it. It fastens securely to the wall, preferably to a stud.



Here's a detail showing the wire bracing. The wires should be tight, but don't pull the eye screws out of the wood or damage anything. Note the turnbuckles and that one of the gussets was cut too short.



This shows an outboard attachment. I bolted some short angles to the outboard rib and clamped them to the support brackets. Worked very well. I used nutplates on the rib but that was foolish; ordinary nuts would have been fine. Avoid the tooling holes or it'll be harder to align the wing.



Finally, here's the inboard main spar attachment. Pretty simple, eh?

Yes, it's clamped, but the clamp is out of sight.



To make this into an empennage jig, I think I'd try to find a straight 4x8, if there is such a thing, and bolt it to one wing's side of the uprights. Probably waist height or counter height would work. Perhaps make a work table for it out of that white Melamine-coated particle board they use for cabinets; it's a nice material to use for work tables.

After the empennage is complete, remove the 4x8 and you've got a wing jig.

Dave

[David-aviator]

As always nice work David.

The attention to detail starting with the jig device and careful construction of various parts will make for a fine airplane.

I remain impressed with your patience and skill with this project.

[David Paule]

I've started the new left-hand aileron. It took me four hours to make these stiffeners. Of course one hour of that was making some angles after I realized that I'd run out and hadn't ordered new blank angles to cut up.

Had some .025 aluminum, so I cut out the blanks, deburred and bent them, and then finished them. Only had to do seven that way since I had enough prebent angle to make the first seven.



That was done yesterday. Today the new parts arrived and I've started working on them. The spar is marked and the end reinforcements made. The skin is marked so that I can drill for the stiffeners and the upper spar cap.

Dave

[David Paule]

Working on that replacement aileron....

Here are the stiffeners riveted to the skin. For builders of the other RVs, the RV-3B has a one-piece aileron skin. This makes it a bit more difficult to build. The skin arrived with the trailing edge bent more than I'd prefer so I used a galvanized pipe that I had handy, about 1 1/2 inches diameter and about 6 feet long, to press into the bend while the skin was trailing edge down on the work table. This opened it up just enough to back-rivet the stiffeners.

If your eyes are sharp, you might see that the aft-most rivets are blind. I didn't want to try to unbend the skin far enough to install solid rivets there. I figured that blind ones were better for that.



The spar gets drilled to the top of the skin early. You can just see those holes in the photo below. I was reluctant to drill the 1 3/4" lightening holes because when I do, the spar warps. It bends away from the flanges. When it's clecoed (and later riveted) to the skin, that goes away, but it's a tiny bit awkward in the meantime.

Still, the sequence would have been affected if I'd waited; the bottom flange doesn't get drilled to the skin until quite late in the process. So I made these holes. Then I riveted the end reinforcement flanges on.

The plans call for AN470AD4-5 rivets but the -4 are more suitable here. For the two flush rivets, those are also -4. And you know what? For all four ailerons I've worked on so far, I missed that their diameter is a 3. Yes, I installed an 1/8" rivet where only a 3/32" was required. But I did manage to have enough edge distance. Those will have to come out for the outboard main ribs and then I can put them back in; they're in now so that the reinforcement lays flush on the spar. Without them it lifts a bit and then when I drill the holes for the nose rib (the next step), it's hard to deburr them.



My drill board is a 2' x 4' piece of that white Melamine-coated particle board I like. It's flat and has a nice finish. It's sold in the big box stores. It doesn't get embedded particles of aluminum and doesn't scratch aluminum. Nice stuff. And this one is getting lighter by the day, with all those holes.

Dave

[David Paule]

The nose ribs that arrived with this aileron had cracks in the front flange. Here's an example:



Van's replaced them quite courteously and promptly. Ironically, the new ribs had their front flanges slightly too low. The pipe was lower than the bottom flange. Unfortunately I don't have a photo of that - the gap was about .06 inches.

Since the ribs were already riveted to the spar, I removed the front flanges and made new ones. Ironic, huh? With the front flanges off the ribs, the position of the pipe needed to be controlled fore and aft. I made a tapered plate of .025 as a guide, and by working on only one rib at a time, I was able to use the other one as a control. That let me mark the guide.



The top edge of the guide, where the tooling hole is, fit flush to the reinforcement on the spar face. I slid it in until it contacted the pipe and marked that, and that located the distance. I used a Harbor Freight die grinder's wrench to hold the pipe to the bottom flange of the rib.

Here it is jigged up:



Finally, here it is with the skin sort of loosely fitted around it Note that I used solid rivets instead of the LP-4-3 blind rivets that aren't specified in the plans - but are in the RV-4 and RV-8 plans.



The skin is now taped into position and the trailing edge is bent again after unbending it somewhat to rivet the stiffeners in place. It's pretty clear that I'll need some shims as before.

Dave

[David Paule]

I had previously bought one of Van's EA OIL COOLER II oil coolers and a shutter for this project. Andy Hill found that on his engine, a smaller one would work okay. He had an Earl's 20700, with an engine that because of some internal differences would put more heat into the oil than mine.

I thought that out here sometimes I'd need more cooling than that. Colorado temperatures are more severe than England's, and I fly over the western deserts from time to time. I bought an Earl's 21000ERL from Summit Racing. It has roughly 38% the cooling capacity of the one from Van's.



Hard to imagine that quite possibly the smaller 20700 one would work fine. It's height is an inch less and the other dimensions stay the same. You can research them here.

This oil cooler is clearly not as well made as the one from Van's. It's almost a pound lighter, though, not counting the shutter and its control. Besides the weight, a side benefit of not using the shutter, assuming I don't need it, will be that I don't need to find a location for its control in the small RV-3B cockpit. I've got the shutter and verified that it can be used with this oil cooler. I'll hang on to the shutter just in case.

One of these days I'll put the oil cooler from Van's in the Classifieds. New, unopened.

Dave