Dale's RV-9A Project

Sunday, July 14, 2013

July 14th, 2013

This week I've mostly been working on the seats. I used the tip for using a metal yardstick as a drilling template to make the drilling of the seat angles/hinges more consistent. My yardstick is riddled at this point since I've used it for 4 different drilling templates.

The first thing was to fabricate the F637B vertical angles for the seat back stiffeners. These get cut out of a long chunk of 3/4 x 3/4 x .125 (1/8") angle.

The F637B gets a notch at one end to provide space for the hinge at the bottom. Not having a milling machine, I tried a couple of things - turned out it was easiest to just file it.

There is a left and right hand version required for each seat, so you have to pay attention not to make two of the same part.

A piece of piano hinge gets cut and drilled for the bottom (this is what attaches the seat back to the floor pans). There are three separate identical lengths of matching piano hinge riveted to the floor skin. This allows for some fore/aft adjustment for leg room as well as a bit of reclining.

Since I also drilled several attach points for the rudder pedals, the plane will easily accommodate a variety of pilot sizes, although any adjustments will have to happen on the ground.

Once the verticals are finished, there are two horizontal angles made from 3/4 x 3/4 x .063, one at the top and one at the bottom.

Finally all of these parts (including the length of hinge) are match drilled to the seat back, which is a corrugated sheet of aluminum. The corrugations provide additional stiffness.

Here's the completed assembly after drilling. The only difference between the left seat and the right seat is the orientation of the hinge at the bottom. Left side has the hinge set up one way, the right is exactly opposite. Other than that they are identical.

A seat back brace F638 is riveted to another piece of piano hinge, which is then attached to the upper back of the seat. This provides sufficient flexibility to accommodate any seat back adjustment, as well as allowing the seat to be folded forward if need be.

This would probably be very handy in a tip up canopy RV, although with the sliding canopy I'm planning on, I don't see much of a need. It would also be very easy to take the seat back out if you had something to carry and didn't have a passenger - *that* I could see doing at some point.

Here's the seat clecoed together and installed in the cockpit. In this shot it is in the middle position of the floor attach hinges.

Here's a side angle shot of the same thing - gives a better idea of how it all fits together. The F638 brace at the top is a tight friction fit into the bulkhead. The grey angled pieces sticking out of the floor are the seat belt anchors.

It's amazing how light and strong this is.

The seat will be a lot more comfortable than it looks. There is a spacer cushion that will be shaped to fit the depression and fit level with the forward seat floor. Then a seat and back cushion will be installed on top of that, so it will end up sitting pretty much like you would in a car. Here's a shot of what an interior looks like all decked out.

Sunday, July 7, 2013

July 7th, 2013

Needless to say there has been a lot going on (Becca graduated from High School, Paul & Becky's wedding, electrical problems with Becca's car, repairing/replacing raillings in porch and repairing some rot in one of the columns, new thermostat for Becca's car, working on the Ody for a long road trip, SOAR for Becca at UNCC, Daytona vacation, and repairing some old fence sections and replacing a rotted fence post among other things).

I have been working on the project as time permits, but haven't taken the time to post an update in a while.

Since the last update I've match drilled and installed the aft seat skins, installed the hinges for the seat attachments, fabricated and installed the tunnel support cover, and started working on the crotch strap attach brackets.

Saturday, June 8, 2013

June 9th, 2013

Sad week last week. My sister in law's father, John D Hall, USAF retired, passed away May 31st. He was a pilot and Vietnam Veteran with over 750 combat hours in an OV-10 Bronco. He is survived by Linda, his wife of 47 years, 4 brothers and sisters, 4 children, Heidi, John, Jason and Jeff, and 5 grandchildren. We'll miss you John.

This week I started on the F751 and F652 bulkheads. These are the corrugated vertical panels that cover the back of the baggage compartment. When I was first looking at it and measuring the drawings, it seemed like an 8" radius circle would be about perfect for cutting the upper edge of the F652 bulkhead.

I often read and look over the plans while eating lunch, and I noticed on one sheet that Van's specified a radius for the cut which I'd overlooked the first time. I'd already laid out the curve from my template, so I made a simple 8 1/2" radius trammel for my sharpie pen to compare them.

The difference in the curve was so small (especially with the difficulty of getting a decent curve inside the corrugations) that I ended up using the line I'd already drawn. Once I had the curves cut and finished, I clamped & clecoed it into the fuse to make sure it all fit and there was sufficient edge distance all around for the nutplates.

Saturday, June 1, 2013

June 2nd, 2013

We've been doing the annual on our Cherokee the last few weeks so I haven't had much time to work on the RV.

As I started working on the baggage compartment floors I realized this and the seat pan area were getting ready to be sealed for good. I know I want to put at least one comm antenna on the belly, and probably two. That got me to looking at the floors, good spots, etc. While I was doing that I realized there was some unfinished business, namely the seat belt anchors, bolt/spacer where the rear spar will attach, and I also missed the rivets at the aft end of the outboard seat ribs. Went ahead and took care of those and final torqued the bolts.

Lousy shot, but it shows the seat rib that needed riveted and the attach bolt and spacer where the rear wing spar will install later.

As I was looking over the forward removable seat skins, I noticed I did not install nutplates on the outboard ribs (no idea why I decided to do that unless I misread the plans - I'd already done all the others when prepping the ribs originally). At any rate, I went ahead and did those.

After looking around at various RVs and thinking about how I wanted to do the antennas, I still haven't decided on my final plan, but I did decide to make the left baggage floor removable so that if I want to put an antenna in that area I will be able to. Turned out to be a lot of nutplates to do that, but I feel more comfortable having the option if I decide to go that way. I put a K1100-08 or a 21051-L08 nutplate at nearly every rivet location.

From Fuselage

The right side F747-R baggage floor skin was installed conventionally. It takes about 10-15 minutes to do it this way, and I'd guess about 4 hours to do it so it is removable.

Left F747-L baggage floor after finishing all the nutplates and screwing it down about half way. Works great and I think I will be glad I did it this way.

Time to finish the aft baggage compartment wall/skins. The upper skin needs some work before it can be match drilled and installed. The top edges need to be radiused first. After looking at it and doing some measuring I concluded an 8" radius would be perfect. I poked around and found a 16" pie pan, made a paper template from it and quartered it. That will be my cutting template once I verify that it looks reasonable.

The lower baggage compartment wall is more or less finished, just needs to be match drilled to the upper part of the F706 bulkhead. I'll start that once I get the top skin trimmed to shape.

Monday, May 13, 2013

May 19th, 2013

Sunday night I had some outstanding work I needed to finish up. When I joined the two fuselage sections together (tail cone and mid section), I never saw in the plans were they called to rivet the baggage ribs to the F706 bulkhead. I'm at the point where it's silly not to (not far from fitting the baggage floors and tunnel in fact) so I decided to do that.

For those that haven't done this yet, this would have been *gobs* easier to do while the fuse was still upside down. As it was I had to go through all kinds of gyrations hanging over the side and trying to rivet these dudes. It's done, but would have been a lot easier earlier.

Next was to match drill the F709 bulkhead to the rear deck/skin. I'm going to leave it unriveted for as long as possible since it will be hard to get my hand/arm through the lightening holes if I need to at some point later (pretty confident that will be necessary later on).

Van calls to rivet the F750 baggage sides at this point, then the next line says it's time to install the steps. One glance at this and you know putting the sides on before the steps is a really bad idea. Much harder to get to the steps. So I skipped the sides and started on the steps.

The plans are separate and were written for a -6, although they also talk briefly about the -7 and -9. Not that different anyway.

There is a small hole in the side that gets enlarged to accept the step tube. I drilled this before I bent the skin and riveted it all. It needs to be enlarged to clear the welds, so I started sneaking up on a good fit - grind/file, test, repeat.

Here's the weldment. Pretty rough piece. Needs some cleanup and priming.

I used tape to make mark my line, then used a coarse grinding wheel to get it to length.

Here's the inside view. The outboard rib gets a couple of clearance grooves and the inboard rib gets a hole. I did both of these before I riveted the center section together.

Getting pretty close to a good fit. The lower aft is well off the skin. I bent it down, but still can't get it tight. Have to google around/ask to see what other ones look like. I'm not worried about the strength, but aerodynamically it would be draggy. If I can't get it tighter I'll have to fair it somehow.

Once I had it cut to length and it was fitting well I drilled it on the drill press using the pattern in the plans.

Here's the outboard plate drilled and ready to go. I trimmed the lower right corner to more closely match the fuselage side.

Here it is match drilled to the skin and clecoed on. The second row of rivets from the left needs to align with the F924 bulkhead.

Once the step was clecoed on it was time to drill the WD657 UHMW block to the rib. I drilled the holes on the drill press prior to this.

To drill the rib and step tube to the WD657 block I used an tight fit angle drill attachment on my drill. Here's the kit I got from Isham's. It's been really handy.

Here's the bit and angle drive fitted to the drill. You can get in a very tight spot with this.

Here's the block match drilled and bolted to the rib and step tube.

Once the WD657 block and tube were drilled and bolted, it was time to deburr and prime the steps and rivet them to the skins.

One thing I figured out (don't know if this is good planning on Van's part or just fortuitous circumstance), if you work the holes in the flange correctly, you can get them to fall right on an existing bulkhead rivet, and all the rest will drop between existing rivets. This makes it 1) easy to line up and get started, and 2) works out really well from just a layout point of view. Here's a picture of the rivet I'm talking about.

Here's the right step riveted into place. Pretty happy with how these came out.

Once that was done I went ahead and riveted the F750 baggage skins into place.

Once the side skins are done, the next thing they say to do is rivet the baggage compartment floors into place.

As Dennis says, I need to do some thinking here. As I was clecoing these in, I was looking at what would be inaccessible, and realized I did not have the seat belt brackets in place. I took them off quite some time ago when riveting the center section, and never put them back, thinking there would be a time later when I would do that. It's pretty clear if I don't do them now, I'll have to remove the floor to get them in. Here are the floor skins in place once I put the seat belt brackets in and torqued them.

I also plan to put the transponder antenna on the bottom of the fuse, and probably two comm antennas. I need to either put in an access plate, make the whole floor removable, or put them in and seal them up (the last one isn't really a serious consideration). For now I'm going to do a lot of noodling/planning/idea stealing, and not actually rivet the floors in since they are easily (and as far as I can tell painlessly) done a bit later.

I also have a couple of rivets on the outboard ribs that aren't done, as well as the spacer block that goes in the rear spar slot and gets bolted in. I'll do those next.

Friday, May 10, 2013

May 12th, 2013

Again, the last few weeks have been really busy. FKN pancake breakfast, early mornings at work for several weeks working on the firewall cluster, internet moves, new router, etc., and working VARFOF last weekend. Fun. I have done a *little* work on the RV, but not a lot.

Since I'm so far behind (again), I'll just do one big post and go from there.

First thing was to get the canopy rails, gussets and the forward canopy deck riveted into place. I've read where folks had a lot of problems with these due to the tight fit. The only place I had a hard time was the forward rivet in the rail, and the aftmost rivet in the deck. I have a small tungsten bucking bar I use a lot, and it fit in the slot no problem. I ended up using a 1/2" socket extension as a bucking bar on aft part of the forward canopy deck. I cannot figure how to buck the two rivets that hold the forward deck to the rail. Over the last few weeks I've checked out a few finished RVs - every single one of them used pulled rivets at that location :). I'd already decided to, but it's nice to know you're not alone in that conclusion.

Here's the right rail and gusset riveted into place. This also ties in the seat back brace/bulkhead. The fuse got even stiffer once this was done.

Looking along the left rail forward after riveting.

Next step was to rivet the F695 gussets to the longerons and firewall angle.

This is the underside of that same piece for future reference and in case anyone wants to know what it looks like. The aft rivet is tight against the firewall attach angle once it's bucked.

Next step was to deburr the shoulder harness attach brackets to the longerons in the specified locations. I put the hardware in place to confirm the fit. This gets put away until later in the project.

The next thing to do was rivet the angle to the bellcrank attach rib.

Once the angle on the bellcrank was riveted, it was time to rivet the rib to the F-706 bulkhead. I'd read where folks had a lot of problems with this, but the pneumatic squeezer with the thin nose yoke had no problems at all.

When I was working on the tail cone I went ahead and cut the top J stringers to length. Now the ends need trimming to fit against the bulkheads properly.

J stringers trimmed and fitted to the bulkheads.

There is a rib that supports the top skin between the J stringers, running fore and aft between the F-706 and F707 bulkheads. There is an angle clip that needs to be fabricated/drilled to provide an attachment to the F707 bulkhead. This will be riveted after the skins are nailed down.

From Fuselage

Next thing to do is fabricate the elevator bellcrank assembly. It was actually called out earlier, but I hadn't primed it at the time. Now that it was primed I went ahead and riveted it together.

Here is the bellcrank installed between the floor rib and the vertical bellcrank rib. The elevator pushrod will attach at the top, and the pushrod from the control stick will attach at the bottom, passing through a hole in the bottom of the F706 bulkhead. The bellcrank is asymmetrical, which gives a mechanical advantage (a small stick movement is translated into a larger elevator throw). There are precision bushings on either side of the bellcrank as well as a bearing in the center, which makes for no slop whatsoever, and a very smooth control movement compared to the more traditional cable/pulley assemblies used on production aircraft.

Next it was time to install the gussets that support the sides of the F707 and F706 bulkheads.

Close up of one of the gussets. I made a mistake drilling the gusset to the longeron (I drilled it prior to clecoing the top skin to the bulkhead. The bulkhead is very thin, and was not properly aligned fore and aft. I had a choice to drill more holes in the longerons (*not* doing that) or make a doubler. I went with the doubler.

The final step was to cleco the skins on and match drill the skins to the bulkheads, rib, doubler and J stringers. Looks like a porcupine from this angle.

I had to order the static port kit from Van's. Since I had to pay the shipping anyway, figured I'd get the VAF hat while I was at it. :)

Friday I didn't have a lot of time to start anything major, so I decided to mock up the tail section to see what it would look like all put together. I held the stabs in place with adjustable clamps, and put AN3 bolts in the hinges so it all fit more or less correctly. Actually starting to look like it might be an airplane.

Subscribe to: Posts (Atom)