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  #621  
Old 03-08-2022, 02:14 PM
terrye terrye is offline
 
Join Date: Feb 2010
Location: Vancouver, BC, Canada
Posts: 993
Default RV-3B Dave's in Colorado

I should have been more specific.
Standard ROTACUT 5/16" through 3/4" seven cutters.
https://www.browntool.com/Listview/t...5/Default.aspx
Large ROTACUT 7/8" through 1-1/2" six cutters
https://www.browntool.com/Listview/t...2/Default.aspx
Master ROTACUT 1/4" through 3/4" sixteen cutters by 1/32" increments.
https://www.browntool.com/Listview/t...1/Default.aspx
Brown Tool as an example, other vendors carry them too.
I have the first two kits and have found them superior to any other hole saw (although hole saw to me implies the cheap not quite round hole saws intended for woodwork) in terms of precision.
When I got the new nose gear (with suspension) and engine mount from Vans having already drilled the rod type mount, I found the hole saws perfect for the 3/8" (I think) holes I had to drill thru the stainless steel firewall and aluminum substructure.
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RV-9A (Fuselage)
2021/2022 VAF Contribution Sent
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  #622  
Old 03-11-2022, 05:06 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 5,308
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Terry, thanks again for the suggestions.

I finished the 1/2" holes with a punch and the two 1 1/2" ones with a Lenox hole saw, bought locally. That's one task out of the way now. Can't say that the .005 Titanium is that much fun to work with, especially compared to the .020 Titanium which actually behaves, at least most of the time, like a real metal.

Dave
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  #623  
Old 03-28-2022, 10:17 AM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 5,308
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The firewall insulation went on after a lot of trimming and fiddling. At the last minute, I had to trim the perimeter back a little to allow for installing the quarter-turn cowl fastenerís mounting strips. And of course I had to trim the .005 Titanium overlay foil, too.

I used 3Mís spray adhesive #77 on the firewall to attach the insulation. It allows repositioning for a bit and then sets firm. I used it again for the overlay foil. Both of these required non-trivial positioning since I had only one real change at getting it right. One side of the foil came out better than the other, of course.

The recess area took the most work. The sides were integral to the main foil pieces but the top and bottom were add-ons. And the top back that went under the heater valve was a separate add-on. I had to do that twice after botching the 2Ē heater air hole the first time. Drilling holes in the .005 Titanium grade 2 foil is something that I find difficult, and I didnít have a 2Ē punch. Here are some comments I made in DanHís firewall thread:

It's easy to drill holes to 1/4" with normal drills. No problem at all.

Unibits, I use Harbor Freight's version, tend to leave a burr. They form a partial cylinder, a shot one, around the hole. The second-best way I've found to remove those is with a coarse mill file. The best way is with a Dremel sanding drum, which does it quickly.

I tried Harbor Freight's 95547 punch set and it was terrible. It did work for some 1/2" holes with a lot of swearing and some burrs, but wasn't worth the trouble. I recommend against it. The smaller holes made by my Whitney Junior punch work fine, but that has a short throat depth and so can't put holes everywhere they are needed.

Hole saws work okay but be sire to clamp the foil well!

All the stuff bolting to the firewall went on smoothly except for one small detail. I hadnít allowed room for the brake reservoir tee to get installed - it hits a cross-angle on the cabin side. But I figured out a work-around, so thatís not a real problem, merely a detail. Iíd made a test of the insulation to see if it takes a set under bolt pressure and learned that it most certainly does. I used the wide-area AN970 washers under the nuts and used the reduced shear fastener torque for all these.

When that was done, I bolted the engine mount on. All the four corner bolts were too short. I had the middle bolts in the right length and a too-short length, so I must have tried this before. Wonder why I hadnít observed that the corner bolts also needed replacingÖ. Once the engine mount was on, I checked and sure enough, there was no way I could rivet the quarter-turn cowl fastenerís mounting strips with the firewall there. Off it came.

There was this detailÖ I didnít need or want the mounting strips where the cowl cheek extensionís bulkheads were attached, and until the cowl was on, I hadnít a firm position for those. But when I was working with the acrylic dummy firewall, Iíd taken a line from the center of the rocker box covers to the dummy firewall and marked them, so I knew where the fat part had to be. Working from those located the bulkheads in a preliminary sort of way. My mentor had sent me some photos showing where the cheek extension was on his plane - thanks, David! - and my locations compared to his to about an 1/8Ē which is close enough at this time.

The photo shows the firewall overlay, less the FireBarrier caulk, and the upper cowl mounting strip. The strip needs scalloping in this photo. The recess was a bit tough. Oh, the brake reservoir is just hanging there upside down now, for convenience while working on that strip.



There are a few magnets visible near the engine mounting points, in case you're wondering.

Dave
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  #624  
Old 04-04-2022, 07:07 PM
David Paule David Paule is offline
 
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Location: Boulder, CO
Posts: 5,308
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I got the top and the bottom side mounting strips done, primed and riveted on. Years ago, I bought a set of Mil-Spec fasteners, not knowing that they’d go out of business leaving Skybolt as the main RV quarter-turn fastener vendor. The two products are substantially similar. These got riveted to the mounting strips and then the strips to the firewall.

The top strip was complicated by needing the nutplates for the forward fuselage top skin, which on an RV-3, is removable.

A decision I’d made back when I was skinning the fuselage paid off - I had not riveted the firewall joint to the side skins, relying on the G/flex epoxy for the joint. That decision paid off because the side strip rivets didn’t interfere with a previous rivet pattern. The riveting on the top was less fun than I’d hoped, partly because of the nutplates but mostly because of the firewall flanges.



There’s still some work needed on this, but most of it’s done. The cowl mounting strips are white merely because I only have white and gray primers right now, and the white is a relatively durable epoxy.

The bottom, in particular, will get a more finished look before too long.

Dave
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  #625  
Old 04-10-2022, 10:51 AM
David Paule David Paule is offline
 
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Location: Boulder, CO
Posts: 5,308
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I had to finish off the bottom of the firewall overlay, as you can see on the last photo in the previous post. There’s no bottom flange on an RV-3B firewall. I made an angle of .020 Titanium and used 3M’s 2219 B/A epoxy to glue it on, following their preparation recommendations. I chose 2216 because they offer strength data to 400 F, plus some useful documentation. This was delayed because I was waiting for some stronger magnets to come in to hold it while the epoxy cured. When they were delayed, I figured out an alternate support technique and that worked well enough. I used weaker magnets and strapping tape.



After over 6,000 hours, it took less than four more to put a few parts on the fuselage. Then it was time for the requisite photo.



The next step is to deal with an unfortunate little weld problem I discovered on the engine mount that will probably require removing the landing gear and engine mount. My AI, who does the annuals on my C180, is coming by to have a look and discuss it with me. He’s helped me with this RV-3B before.

Dave

Last edited by David Paule : 04-10-2022 at 10:54 AM.
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  #626  
Old 04-13-2022, 04:29 PM
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rockitdoc rockitdoc is offline
 
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Location: Fort COllins, CO
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Dave,
Looking good.
Scott
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Begun 07-23-20
Emp Completed 11-12-20
Slo Fuse Completed 3-2-21
Wiring and Avionics Begun 3-3-21
QB Wings Begun 3-1-22
Finish Kit and FWF work in progress
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  #627  
Old 04-14-2022, 06:47 PM
David Paule David Paule is offline
 
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Location: Boulder, CO
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Thanks, Scott.

The small weld issue mentioned above is an incomplete weld. It had the appearance of a crack but wasnít, exactly.
Iím an old aerospace engineer and have done many crack propagation analyses, and felt it needed to be repaired.
Checked with my certified airplaneís AI, who said to repair it. So did my mentor, another engineer, and Vanís support. Actually Support said that this area might crack anyway at some point, repaired or not, but that it would be better to repair it.

Itís at the top of the right landing gear socket and is in that red circle.



After pulling the landing gear legs off and removing the engine mount from the fuselage (which I hated to doÖ.) I removed the cadmium plating in that area with Muriatic acid. Some of you will cringe at this, but I did it in the kitchen sink, it being way too windy to attempt it outside. The stainless steel sink wasnít affected by the few drops of acid that landed on it, and with the faucet going, there was ready dilution. My exhaust fan vents outside and is unusually powerful. I opened a window and got positioned so that the flow was window to me to sink to fan, and I was in clean air.

After an hour, the plating was gone in that area. The actual welding took no more than two minutes. I put primer over the non-plated areas, bolted it back to the firewall and reinstalled the landing gear. Done.

Since I hadnít known when things could happen, I had a bit of spare time between the plating removal and the welding. Iíd been working slowly on the engine baffles as fill-in projects. With the usual cursing, I was able to get the back baffle pieces in place. As you can see from the untrimmed top of the baffles, the ignition cable draped over the top, and the fact that the blue vinyl is still on and a couple other minor things, this is still a work in progress.



Dave
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  #628  
Old 04-16-2022, 06:41 PM
David Paule David Paule is offline
 
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Location: Boulder, CO
Posts: 5,308
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The small weld issue mentioned above is an incomplete weld. It had the appearance of a crack but wasn’t, exactly.
I’m an old aerospace engineer and have done many crack propagation analyses, and felt it needed to be repaired.
Checked with my ferried airplane’s AI, who said to repair it. So did my mentor, another engineer, and Van’s support. Actually Support said that this area might crack anyway at some point, repaired or not, but that it would be better to repair it.

It’s at the top of the right landing gear socket and is in that red circle.



After pulling the landing gear legs off and removing the engine mount from the fuselage (which I hated to do….) I removed the cadmium plating in that area with Muriatic acid. Some of you will cringe at this, but I did it in the kitchen sink, it being way too windy to attempt it outside. The stainless steel sink wasn’t affected by the few drops of acid that landed on it, and with the faucet going, there was ready dilution. My exhaust fan vents outside and is unusually powerful. I opened a window and got positioned so that the flow was window to me to sink to fan, and I was in clean air.

After an hour, the plating was gone in that area. The actual welding took no more than two minutes. I put primer over the non-plated areas, bolted it back to the firewall and reinstalled the landing gear. Done.

Since I hadn’t known when things could happen, I had a bit of spare time between the plating removal and the welding. I’d been working slowly on the engine baffles as fill-in projects. With the usual cursing, I was able to get the back baffle pieces in place. As you can see from the untrimmed top of the baffles, the ignition cable draped over the top, and the fact that the blue vinyl is still on and a couple other minor things, this is a work in progress.



I removed the baffles for the next step, in spite of being able to progress with this. It was time for something else.

Remember that the engine was on my work table. I’d made a crucial error building the table back in ’12; I hadn’t allowed enough clearance under it for the engine hoist, or even a floor jack. Wirejock (AKA Larry Larson) came by to help and so did mtnflyr (AKA Rick Brennan) to help with the engine installation. Larry hoisted the table, I shoved the jack under it and lifted, Rick stabilized the engine, and we maneuvered the hoist in place and picked up the engine. I’d moved the fuselage partly outdoors to get more room in the shop for this, so we put the engine in place.

With rather a lot more work than I’d expected, Rick and Larry got all four isolators, bolts and nuts installed. I certainly could not have done it by myself. Fortunately both guys had not only done it for their planes, they both offered to help me. I did very little; they were the installers. And I’m mighty glad that they were both here.

Thanks, both of you!



They look a bit concerned because at this moment it was not going smoothly.

Once the job was done, they left, after posing for this job well done photo.



Afterwards, I torqued the nuts and took this close-of-day photo.



These guys saved my bacon more than once. Thanks again.

The engine’s on. Now there’s lots of things I can do.

Worth noting is that with the tailwheel on and about 30 pounds of weights on the aft deck, the plane is stable. When I raised the tail and it approached level, though, it was getting awfully light. Those weights are important.

Dave

Last edited by David Paule : 04-16-2022 at 06:48 PM.
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  #629  
Old 04-16-2022, 06:57 PM
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wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 5,230
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You have helped me more than I can account. This was the least I could do. Rick had the genius idea. The last bolt (bottom/port side) didn't want to cooperate. He used a pry bar to move the mount just a tiny bit and it slipped right in.
So happy we could help. Be well my friend/mentor.
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Donated 12/01/2021, plus a little extra.
RV-7A #73391, N511RV reserved (3,000+ hours)
Empennage, wings, fuse, finishing kit done. Working FWF
Disclaimer
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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  #630  
Old 04-17-2022, 07:50 AM
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jcarne jcarne is offline
 
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Congrats on the milestone Dave!
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