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-   -   RV-3B Dave's in Colorado (https://vansairforce.net/community/showthread.php?t=85658)

David Paule 09-07-2013 08:46 PM

Not Exactly As I'd Intended
 
When I pressed the leading edges down on the frames, the leading edge radius looked too large. Starting with the right one, the aft one in the photo, I was able to correct that and the leading edge then fit very nicely on the ribs. I drilled and clecoed the bottom of that side.

Looking more closely, I found that in between the ribs, that there was a flat spot just aft of the leading edge radius on the top in between the ribs. Since I'd rebent the leading edge radius that was clearly my fault. I attempted to add some more curvature in those areas and didn't succeed. Scratch the right-hand leading edge skin.

A friend came over to help with the left one. He had some excellent suggestions but it appeared inescapable that I'd have to rebend that leading edge radius too. Well, I botched it, putting that bend slightly out of position. That scrapped that leading edge skin too. This wasn't going the way I'd hoped.

I ordered new parts and started the tanks in the meantime. I had been looking forward to the tanks anyway - maybe it comes from playing in the mud when I was a small child, but gooey things are sometimes fun, and I'd enjoyed using Pro-Seal before.

Here are the ribs on the right-hand baffle, just getting started. The left one is at the same stage.



Dave

David Paule 09-15-2013 03:38 PM

Flood Clean-Up
 
I got hit less than a lot of folks and I'm pretty grateful for that. One of my friends lost everything, including an entire workshop with a lifetime's collection of tools.

Still, I've got a basement that's going to take some cleaning out, and the RV-3B project will be on hold while I do that. The RV-3B was not in the basement and was completely unaffected out in the garage.

At this point, the clean up is just a matter of labor and time, plus I get to practice my swearing.

I'll get back here when the project's underway again.

Dave

David Paule 09-23-2013 05:44 PM

Cool Parts Found While Cleaning the Basement
 
I had more water damage than expected, and had to remove more things than anticipated. And of course there's a bit of mold correction and I've been replacing things that can get moldy with things that can't.

Only four inches of water and silt can sure make a mess!

One good outcome was that I found a can of assorted AN hydraulic tube fittings that I'd "lost" down there. This is definitely RV-3 related. Plus I found a perfectly good helicopter airspeed indicator that I'd forgotten about which covers the RV-3B speed range. It's calibrated in knots, and if I use it, that'll make the decision between mph and knots. Since my Cessna 180 uses mph I'm tempted that direction, but of course the rest of the world uses knots so that's tempting, too.

Which reminds me that one day, back when I had my Corsair F-27 trimaran sailboat I was buried in work with a laser equipment client, and took a brief break from that to see what was going on at the trimaran forum. Someone was using the letters "nm" and I couldn't understand why nanometers, a common (and very tiny) measurement for laser development, would be used in sailboat operation. Too much work, eh?

Another potentially useful finding was one of those control stick grips with many switches. For emphasis - far too many switches. Too many for a day VFR airplane. This too is tempting, though I don't know what I'd do with all that switchology. For example, there's the common trim hat button. My RV-3B will have mechanical trim. This thing might be overkill. I haven't weighed it but it's not light.

Anyway, I'm still plugging away down in the basement but things are now at the stage where I'm looking towards completion. I can see it but I'm not there yet.

Dave

David Paule 10-06-2013 07:52 PM

Back To Building the Tanks
 
Looks like back when I was prepping my tank ribs, I drilled a vent hole on the inboard tank rib and then accidentally put that rib at the outboard end instead. Now I've got a nice hole that I've got to patch and a proper hole on the inboard rib to drill.

Yes, I'm back to work on the RV-3B after the flood. It's been about a month. I'm working on the tanks and I'd left all the parts where it was easy to resume. In the interim, I cleaned out my basement. That wasn't something I'd planned on doing all at once but the flood, which left about four inches of water down there, provided me with some motivation.

Today's job was fitting the fuel tank baffles and ribs and Z brackets to the wings. At the end of the day they are almost ready for fitting the tank skins, but still need the rib-to-rib spacing supports that will hold them straight.

You can see my extra hole on the left-most tank rib. This is the left wing. You can see a bit of the right wing in the background.



At the L.O.E. fly-in, it looked like it might be a good idea to install a second set of tie-down fittings near the wingtips. The standard tie downs are about 11 feet apart, and with airport tie-downs being 25 to 35 feet, the ropes are too shallow an angle to the airplane of the ground. This will help fix that.

I made a quick analysis (my line of work before retiring) and decided that the RV-3B spar web and flanges are strong enough for that load, although I can't say there's a lot of excess strength there for this.

Dave

Ironflight 10-06-2013 09:03 PM

The dimensions of the RV-3 do pose some interesting conundrums Dave - like tie-down ropes being too short (which is why we carry our own). Then again....I was talking to an Air Force Active Reserve mechanic yesterday (she was volunteer security at the airshow I was attending), and she allowed that the wingspan of the -3 would fit nicely inside a C-5A - with room to spare. That lead to the topic of an air launch..... :)

David Paule 11-10-2013 10:34 AM

Looks like I was too hasty getting back to the RV-3B after the flood. Some friends are needing a lot of assistance and I've been helping out, which takes up my time. And unfortunately there's another time-taker on the near horizon, too.

BUT -- I put the finish kit on order and the rest of the sole-source items. With a little luck, they'll all be safely in the hangar soon along with the engine and the fuselage kit.

And, in the moments when I've got time, I've been fitting the tank skins to the tank ribs. Remember that this is a non-pre-punched kit. It's not a sure thing.

Dave

David Paule 11-14-2013 06:08 PM

Right Hand Tank Skin Strapped Down
 
Recently, I’ve been having trouble getting the tank leading edge to lay fair. You can read about that in the RV-3 section, in a thread titled “Leading Edge Woes.” Here’s a photo of the affected area:



I apologize for the quality of the arrow I drew to the flat area just aft of the leading edge bend, but if you can follow it, that’s where the flat area is.

The right-hand tank skin is strapped down at the moment. The aft top edge is positioned so it butts to the top main skin.

Those 1” squares of .063 overlap the tank skin and hold it in place. That was a good idea from “27 Years of the RVator.” One of our tool companies should produce those and sell packets of them since I'm getting tired of making them. (If you’re a tool company looking for a simple useful product like this, the #40 hole is 1/4” from an edge, and all edges must be smooth and rounded. If they're straight too, that's a bonus sign of good quality)



I'm using the outboard skin to provide lateral positioning. As you can see, it's not strapped down.

Strapped like this, we can look at the inboard rib to see how it looks on the inside. Since I haven’t put in the access hole yet, we can’t see how any other ribs are fitting. But by feeling them from the outside, through the skin, they’re okay. The only area of concern is just immediately aft of the leading edge radius in between the ribs, as I've described.



To me, it looks like except for that area of trouble, the top is basically okay. While there's some gapping on the bottom, once the top has been drilled and clecoed, I should be able to make that go away. And if I'm careful, I'll be able to get that small gap on the top near the front to disappear.

Before drilling, I'll pull the skin off and double-check everything, especially my notes for where the ribs actually are.

Dave

rockwoodrv9 11-14-2013 07:37 PM

Looking good Dave. I can imagine how difficult it is to get the skin-ribs to line up and then get drilled. Have fun!

Ironflight 11-14-2013 07:58 PM

Hey David - in your past picture, that little gap on the upper surface between the rib and the skin is exactly where if have slight depressions on our QB wings - that's about where the forward-most rivet sits. If you can work a shim in there, you might have a smoother wing.

David Paule 11-14-2013 09:41 PM

Now that's darn good to know. Thanks! Actually, I wasn't sure if that was a mis-bent rib flange or it it was real.

And if you look very closely at the inboard edge of the skin right about in line with the upper forward notch (hate that word, as an old stress guy it's just not right) in the rib, you can see where the factory leading edge bend stops and the flat area of the skin starts. It only goes an inch or so. I hadn't noticed it on the photo before. Makes me wonder if it's an artifact of the rib after all - something to explore when I'm back home and working on it again.

Thanks again.

Incidentally, it was for the fun of sorting through these issues that I am building the slow-build RV-3B. Gotta say I'm getting my money's worth.

Dave


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