RV-3B Dave's in Colorado

[David Paule]

...Except for the tips, that is.

I put it under the window in the sun to relax for a while. This is the second one, remember, since I scrapped the first (it's in the rafters now).



Incidentally, the first took 201 hours to build and this took 104 hours. This one's a keeper.

After cleaning the shop I continued work on the rear spar of the vertical stabilizer, deburring the holes and dimpling the channel and countersinking the doubler. It's only the bottom 10" of holes that get this treatment, since that's where the spar rests against the last fuselage bulkhead.

Dave

[rockwoodrv9]

I gota tell you, the first looked pretty good to me! This one must be PERFECT!

[RWoodard]

Nicely done, Dave. Congratulations on the first big piece!

[David Paule]

Originally Posted by rph142

I'm having flashbacks to when I decided to toss my first HS. The second one should be much nicer in half the time so dont sweat it. You'll be glad to have this spare to practice on when it comes time to paint.

Rob, you were bang on with the time and quality estimates.

Dave

[David Paule]

The vertical stabilizer's rear spar is riveted together.



The only things to note are that the rivet sizes suggested in the plans are just that - suggestions. In most cases I was able to use one size shorter, but for the bottom hinge I needed one size longer.

Also, it was worth getting the aft fuselage bulkhead from the fuselage kit before shaping the bottom contour of the spar. If you look at other builder's photos, you'll note some variation there. Having the bulkhead ensured that this would fit.

The tailspring mount attaches to the bottom hinge lower piece at the outboard holes, so these are left undrilled for now. They'll get drilled on assembly to the fuselage.

Before shutting down for the night last night, I drilled the rear spar and the ribs for the rib locations and did the same for the front spar and the top rib. The frame is setting on my table now. The lower main rib and the front spar are still undrilled. I need to confirm the geometry first.

Dave

[David Paule]

This one was fun. In my opinion it should be done before the horizontal stabilizer - it's cheaper and simpler.



Dave Dooley helped me rivet the forward spar to the skin and I did the skin to the ribs during the presidential debates last night. Today I finished that and did the skin to the rear spar.

Here's something that might be worth considering. The skin and the flanges are .032. I used the substructure dimple dies from Cleaveland for the underneath parts. I used the rivets that the plans suggest, AN426AD3-3.5 and it was hard to get these consistent. It turns out that the standard rivet measuring tool measures .139, while the rivet spec on Van's site says the the minimum diameter of a shop head should be .122 inches.

I got a piece of scrap and drilled a .125 hole. This gave us a minimum "go" gauge. We used the standard rivet gauge as a maximum "no go" tool. We made sure that none of the rivets would fit in my homemade gauge, and that they would all fit in the standard one.

This gave us shop heads which were within the .038 to .050 high specification. I used a 4" digital caliper from Harbor Freight to measure these.

Here's the riveting spec: http://vansaircraft.com/public/Specs.htm

Dave

[David-aviator]

You're in the groove now, Dave. The parts look great.

I would have screwed up the first attempt also, building from a pre punched kit has spoiled me. I look at some of the pre bent, pre punched parts with the 8 kit and just wonder at the time it would have taken to make them.

But that's how it was done 25 years ago. The success of Van's airplane company was in the great original design and then focusing on making it easier to build.

It is also a credit that they still sell and support the 3B. For sure there is total satisfaction in doing what you're doing - it makes me think I should have kept the 7 and built the 3B - and won a lottery to boot.

[David Paule]

I disassembled the empennage jig today. That thing has been wonderful. It's been very solid and adaptable and worked for both the horizontal and the vertical stabilizers.



The yellow piece closest to us is the main horizontal member. The triangular ends make a fork that fits around the wood which you can see on the yellow vertical stands behind it. The wood pieces face each other in the photo.

Then there are three large bolts which tie the vertical pieces to the horizontal piece. You can see the holes in the nearest vertical post.

The blue beam, a box made of 1 X wood, screws to the top of the vertical posts. The box is relatively large and provides huge stiffness.

Finally, the feet are 1/2" bolts through the ends of the vertical stands at the widest parts. These are individually adjustable. I used a quick-drying body filler to secure these to the floor so that I couldn't push the jig around. A chisel removed the body filler.

I'll sort of miss it. It was a good tool. It's made four or five sets of stabilizers so far and is in good enough shape to make several more. But it goeth back from whence it came.

In the background, nestled quietly in the workbench, you can see the skins for the rudder and elevators. Other parts are on other worktables. The focus has already shifted.

Dave

[David Paule]

The rudder's built. It was relatively straight-forward, except as noted in the RV-3 section, in the "Plans Clarifications" thread.

Here's a trial fit-up with the vertical stabilizer on the bench. At this point the leading edge of the rudder has been formed but not drilled nor riveted. I remembered the strips on the bottom to attach the fiberglass rudder bottom. These are visible at the left.



After some tweaking, I riveted it up.



I still need to do a final adjustment to the bearings but this is about it. You can probably see that I used gray SEM primer for the spar and ribs but yellow zinc chromate for the skin. I think that the zinc chromate probably gives some additional corrosion protection, and wanted to try it out.

Incidentally, those thin jam nuts on the rod-end bearings aren't to prevent it from turning. They carry flight loads (axial and bending), and should not be overlooked.

In the bottom photo, you can see some regular marks on the rudder skin. Look carefully and you'll realize that they are reflections from the drill board behind the rudder.

Dave

[David Paule]

A couple things have been going on lately. First, I worked on the right elevator and decided that actually I prefer to replace it. The crux issue is that I overbent the trailing edge and can't open it up. There were some minor issues besides that, but this is the big one.

It happened during a brief period when something stressful was occurring and I went out to the shop to work on the plane to relax. Bad idea. As a friend pointed out later, I should have done a few push-ups instead. Scratch one elevator.

Overlapping this, rockwoodrv9 was getting his engines. Plural in this case, since one of them is for me. I don't have it yet. We're planning on getting together next week to make the transfer. Here's both engines in his house.



Since all I have thus far is the empennage, wing and fuselage kits, and I'm struggling through the empennage kit (it's great fun but not easy for me), this engine represents a significant increase in the investment. The fact that I won't need the engine for another two years added to the angst.

When the time comes I know I'll have lots of questions about the engine. The two important ones I know of so far are how to convert it to a constant speed prop engine, and how to de-preserve it. We don't need to bother about these yet, though.

So here I am. Still working away and about to start the left elevator. I'll order the parts for the new right elevator when this is about done. No point ordering it until I'm sure I don't need to replace something with the left one too.

Dave