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Old 04-30-2019, 05:26 PM
David Paule David Paule is offline
Join Date: Dec 2009
Location: Boulder, CO
Posts: 3,795
Default Deep In the Cave

Got to say that itís getting narrow in here. The cave is the tailcone; Iím in it as far as the F-309 bulkhead, where my shoulders are wedged. The gray things on either side are my elbows and arms as I was holding the camera over my head. Weíre looking forward.

The bright white circle is a lamp. Itís off right now but its reflector did a good job with the cameraís flash.

You can see the back side of the F-308 bulkhead, then the seat bulkhead, and out in the open, the instrument panel. It ought to be apparent why RV-3 builders need to remake the fuselage bulkhead flanges. And if you look closely, you can see that the F-308 bulkhead still needs to be joined - itís splice plate is made and drilled but not installed.

Right now, the top tailcone skin is clecoed from the front back to the F-308 bulkhead.

Just thought that you might enjoy the view from the cave.

The photo is also here.

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Old 04-30-2019, 07:42 PM
David Paule David Paule is offline
Join Date: Dec 2009
Location: Boulder, CO
Posts: 3,795

Tonight, I crawled into the tail area of the fuselage to back drill the rivet holes from the front and back bulkheads and the longerons into the top skin. Since there are no flanges on the middle two bulkheads, F-308 and F-309, all I did was the perimeter.

From the work platforms, I could drill back to about the static ports, maybe slightly farther. For the aft-most, I figured that I could round up one of the neighbor kids. It turned out that with a longish bit in the 90 degree angle drill, and some effort, I could drill the aft-most bulkhead and the nearby longerons through that bulkhead.

Yes, somewhere deep in the cave, I made a blood offering to the gods of the sky. Did not plan that.

Some trimming will be required.

The photo is also here.

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Old 05-08-2019, 07:35 PM
David Paule David Paule is offline
Join Date: Dec 2009
Location: Boulder, CO
Posts: 3,795

With the help of my mentor, I made a list of things that need to be done before I glue the turtledeck on.

1. Cut the slots for the shoulder harness. They need to clear the as-yet undesigned canopy frame.
2. Install or at least prep for the transponder antenna. Install the transponder mount if access will be restricted later.
3. Make and fit the baggage compartment aft bulkhead.
4. Install the ADAHRS mount and maybe the ADAHRS, too, depending upon access.

You might recollect the ADAHRS brackets I’d made earlier.

It was intended to rivet these brackets to the aft face of the F-308 bulkhead, fairly high, so that it would be out of the way for cave access and away from magnetic interference. Turns out that while it would function fine there, mounting it to the 1 degree alignment accuracy would be a very iffy proposition, perhaps more frustrating than fun. I’m only building this plane for the fun of the project, so I need to design something easier to align. As the project progresses, my frustration tolerance has not increased. I’m just more used to it. It looks as if I can get the ADAHRS close enough to the tail for access through the F-309 bulkhead, the one at the top front of the aft shelf, if the elevator pushrod isn’t in the way, which I think it might not be. It appears to go through the next hole down. The ADAHRS would be accessible through the bulkheads’s top lightening hole.

After considerable hand-waving and playing around with pieces of angle, I came up with an ADAHRS mount that has the reliable alignment I wanted and continues the slide-in removal feature of the first version.

It is easily removable through that top lightening hole, as hoped.

The photos are also here, and here, too.


Last edited by David Paule : 05-09-2019 at 07:46 AM. Reason: Removed stuff previously posted, sorry.
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Old 05-12-2019, 02:55 AM
RV3Kev RV3Kev is offline
Join Date: Sep 2017
Location: Traralgon Australia
Posts: 22
Default Rivet + Adhesive ?

Dear Dave

Why the adhesive plus riveting? Using adhesive adds weight so I'm assuming that there is some net benefit.

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Old 05-12-2019, 07:09 AM
David Paule David Paule is offline
Join Date: Dec 2009
Location: Boulder, CO
Posts: 3,795

Kevin, It does a couple of things besides absorbing time and money and supplying weight.

The big thing is that it fills small gaps that might otherwise exist in the airframe. The RV-3B has many of those, or at least mine does; maybe not so much for a better builder. The glue acts as a sort of liquid shim.

The second thing is that once things are glued, they can be riveted at leisure and there aren't any clecos to mess with. It's a great holding fixture. Just don't forget the rivets.

Here and there, mostly for small things, I'm skipping the glue. The ADAHRS bracket, for example, isn't glued. But most of the fuselage and certainly all the fuselage skins are glued.

I regret not gluing the wings and tail. On the other hand, they're done and they might not be if I were gluing 'em. It sure adds to the time involved.

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Old 05-12-2019, 07:13 AM
ColoCardinal's Avatar
ColoCardinal ColoCardinal is offline
Join Date: May 2010
Location: Morrison, CO
Posts: 353
Thumbs up

Looking great David. It is tough work avoiding
"painting ones self into a corner" on a project such as this. Thanks for sharing, once again.
Carl - - Morrison, CO
Airworthiness cert issued 12/24
best X-mas present I could have hoped for!
paid 'til 10-19
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Old 05-14-2019, 07:37 PM
David Paule David Paule is offline
Join Date: Dec 2009
Location: Boulder, CO
Posts: 3,795

The ADAHRS mount is complete and aligned. This photo was taken after riveting.

You might have been wondering how Iíd hold in in place, and assumed Iíd put screws through the holes on the flanges. That probably would have worked but it wasnít my plan. I felt that it would be too hard to install a screw and a nut, probably nylon or brass, with one hand working through that bulkhead hole. If you look into the hole on this photo, youíll see that itís terribly misaligned.

The misalignment was intentional. The idea is to thread a ty-wrap through it, around the front of the unit, and snug it up from the back. This can be done, I tried it, but it isnít all that easy. But it works. The ty-wrap pulls the ADAHRS forward against that front stop, which serves both to locate it in yaw and position it longitudinally. Thereís a ty-wrap on both sides for a little extra security. This is shown with loose ty-wraps in the next photo.

Moving on to the baggage compartment close-out, which needs to be removable, the manual lists three drawings that supposedly describe it. In fact, none of them refer to it at all. But the RV-4 and RV-8 preview plans say it uses #8 screws. They donít say how many. Since itís not structural, I arbitrarily chose to use four of them.

Here itís shown fitted in place. Amazingly, it fits. Itís not pretty but it fits. I was astonished. Since it does fit, I can almost forgive the poor formed shape that it has. Iíd like to see the tooling that produced that. Take a look around the top contours to see what Iím referring to. Isnít that something?

Well, no complaints here. I signed up for this with a good idea of what I was getting into. I did have to trim the bottom edge to clear the floor.

Thereís zero chance of merely dropping a screw from the close-out into the surrounding bulkhead because although it fits, thereís little in-plane overlap. Brackets are required, so I made four and glued and riveted them on. Here, the glue might help with the overhang. The brackets attach to the front surface of the close-out and extend past the peripheral rim to the bulkhead. The bottom nutplates were installed but at the top, the plywood bulkhead stiffener prevents that for now.

I made the transponder antenna doubler and riveted that in. Thanks to Rick Brennan for bucking help. Itís the gray rectangle above the elevator pushrod.

Iím using Delta Popís ďUltra Low DragĒ antenna, and a pretty thing it is, too. But Iím not mounting it yet.

Incidentally, I checked with the manufacturer of the antenna about priming the skin or the doubler. He said that with hole-filling rivets (that is, the rivets we use) people report good results. Also the antenna base is plastic, not metal.

The left-hand seat belt anchor was mislocated originally. I moved it inboard to a new location, after getting some advice from Support. Thanks Vanís - seven years after buying the kit, theyíre still supporting a discontinued model.

And finally, I figured out where to put the outside air temperature sensor. I understand that there are as many opinions about this as there are RVs, so I took my mentorís advice, and placed it on the F-310 bulkhead, at the forward end of the aft shelf. Itíll be under the tail fairing and easy access to the nearby ADAHRS.

The secondary photo hosting is at here, here, here, this place, and yeah, here, too.

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