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RV-10 Finish Kit

This page documents the RV-10 finish kit. This includes the doors, engine mount, seats, landing gear, tires and brakes. The cronological order of this section followed the section numbering until after the Sec 46 Engine Mount/Landing Gear. I then went on to Sec 48. Gear Fairings which are best done without the engine and wings mounted. Then FF1 of Firewall Forward kit to mount the engine. Then back to Sec 47. Spinner and Cowl which requires the engine to be mounted.





Notes and Photos

12/12 to 12/26/09

31 hrs

Sec 46

Engine Mount and Landing Gear
This section requires a lot of drilling of steel so be ready with sharp drill bits and cutting fluid. Don't panic when your engine mount holes don't line up, the mount can be muscled over the holes. It took a couple of hours to install. I thought I was going to have help with the landing gear but wound up raising the fuselage with Zeke. Gear legs went in with no problem. I used a brake hone to prep the receptacles and greased the gear leg before inserting. The hardest part of the job was drilling the axel to accept the cotter pin which holds the main wheel nut in place. It was nice to be working with metal again. The airplane is now too tall for the workshop and has been moved to my main garage. Wow, what a difference with it being up on gear!

Zeke pulling on rope to raise fuselage.

Standing on the mains.

Nose Wheel
The kit ships with a Matco NW501.25 wheel which is not correct for a 5.00-5 tire. If you haven't mounted it yet, Matco will switch the wheel for a NW511.25 which is correct for that tire. This will prevent valve stem interference with the nose fork. I also upgraded the axle to the Matco axle (WHLAXLE24 and WHLA24SPKIT) to prevent axle rotation and damage to the nose fork. Both of these issues are documented on the Matronix RV-10 newsgroup.

Regarding installation of the Matco axle, after you grease the bearings and install on the race, clean any grease off of the exterior of the bearing grease seal. This is important because you are going to depend on friction between the seal and the axle to keep it from rotating. Bearing preload is set by tightening until the grease seal does not rotate reletive to the axle. See my post on Van's Airforce forums if not clear. Also, before drilling the hole for the axle anti-rotation bolt, the bracket for the wheel pant must be in place so you know where the slot is located.

Nose wheel.

Machining main axle extensions.

I am using exterior brake hoses from Bonaco Inc. You wouldn't know it from his web page, but if you call him and tell him you are building a Vans RV, he already knows what length hose and fittings you need. I just need to install the brake hoses and bleed the system and then I am finished with this section. I am using the method of pulling the system down from the slave cylinder but am having trouble getting rid of an air bubble in between the co-pilot and pilot master cylinders at the high point of the brake line where it passes over the center tunnel. I tried having Zeke press the pedals for me while I am under the airplane but his paws don't fit on the pedals correctly.

The annual inspection on the Piper Dakota was completed this week. Now that the lonliest holiday of the year is over I will get this finished up and move on to the next section. Maybe even do some flying. :)

2/28 to 6/12/10

132 hrs

Sec 47

Spinner and Cowl
First task is to mount the spinner to the propeller. You fabricate the back plate and then mount it to the propeller along with the front plate. Then you start to trim the spinner to fit. Since this is a variable pitch propeller, you have to leave room for propeller movement. How much is not quite clear until I found a cut out template on internet. Right click and Save this link to your computer. Template It prints out in full scale so you can cut it out and trace onto your spinner. After that is completed, you use 0.060 sheet to fill the void aft of the blade where the spinner does not cover. I spent quite a bit of time on this perfecting the fit.

Spinner Mounted

Top Cowl and Fixture

Backplate Fixture I didn't want to have the prop on for any significant time for fear of damaging it by hitting it with my head repeated times. I found a write up on Van's titled "Simulating the Propeller for Fitting the Cowl" which describes how to make a backplate fixture. Unfortunately the measurements are not for the RV-10. The correct RV-10 measurements are 13.125" dia for the backplate with holes for prop bolts of 0.5" dia. The bolts used are 1/2"-20 of 2.5" length. The standoffs are of length 1.570", 0.750" ID and 1.000" OD.

Top Cowl I started by masking the fuselage with tape and then marking a line 2" back from the forward edge of the skin. I then trimmed the cowl a little at a time until I was clear of the skin and had zero clearance at the prop. I then used the now exposed skin edge to mark a line 1/8" into the cowl. I sanded to this line and this resulted in a perfect fit against the skin with 1/8" clearance at the spinner backplate fixture.

Bottom CowlThe bottom cowl is attached to the top cowl at the very front and then you attempt to trip and raise the aft portion of the cowl to close the clam shell. I was conscious of my spinner to cowl clearance while doing this but you keep losing degrees of freedom as you proceed. When I was finished, my bottom cow clearance was only around 0.050" rather than the 0.125" in the plans. Once I was finished trimming, I took a belt sander to the front face of both cowl and adjusted the gap back up to around 0.100" or so. I had to add back around 4 or 5 layers of fiberglass to the inside of the lower cowl to make up for what I removed from the front.

I also tried to seal the inside of the cowl since it will be a catch basin for oil and dirt. I bought a spray can of primer/filler at Autozone but the spray was very narrow and was not practical for covering a large area. I did the best I could and then returned to my two part epoxy primer that I had been using all along. The Autozone primer seem to fill most of the pinholes and I got a pretty good seal with the epoxy primer.

Zeke studying the plans

Finally clam shelled!

Bottom retainers

Sealed inside

The plans do not include any mechanism to secure the rear vertical hinge pins of the lower cowl. I copied a design from Dave McNeil which uses a section of piano hinge with a nut plate attached on the interior and a SS screw and fiberglass washer on the outside. After much angst over how to retain the cowl horizontal pin, I went with a design similar to what is in the plans except with a 90 degree vertical bend at the end of the pin and a recessed retainer. The retainer is made from a piece of piano hinge and takes a SS screw into a nut plate mounted to the top cowl. The recess was carved out using an engraving bit on a Dremell drill.

Finishing the cowl has been the worst fiberglass work so far. The honeycomb structure adds a texture to the outside of the cowls which needs to be filled to have a smooth surface finish for painting. Smooth-prime filled the pin holes but didn't seem to be able to fill the larger voids. Super-fill does a good job of the larger voids but has to cure over night before sanding. Between the two fillers and several episodes of filling, sanding and spraying, I will soon be finished. One day after sanding and being covered in white primer dust, I came in the house and immediately put all my clothes in the washer. Later I found my cell phone had been through a normal, cold wash with spin dry.

Front Retainers

Rear lower retainer

Oil Door Latches

Finished Product

Final thoughts: This was a long, dusty, difficult section of the plans and I am glad it is over. I think I would rather build another set of doors that build another cowl. I used to have a Piper Warrior that had a hinged top cowl that would flip up with only unlatching two quick releases. That was a great cowl design. I now own a Piper Dakota with a top cowl that has two quick releases on each side and four up at the spinner. The rear only has alignment pins. It is easy to take on and off but not as easy as the Warrior. I find I don't spend as much time under the cowl of the Dakota as I did the Warrior. The RV-10 cowl is a super tight fitting, stream lined cowl. It takes release of the upper pins and then their removal, release of the side pins and then their removal, and then release of the spinner latches. Then wrestling with the hinges to remove it. I can already see that with this amount of work to remove the cowl, that a pilot would be less prone to do it.

12/26/09 to 2/26/10

121 hrs

Sec 48

Gear Fairings
This section starts with leveling the airplane on jacks with the main tires off of the ground. I bought a jack stand from Harbor Freight and cut 15" off of each leg and the center post. I like it because it is sturdy and the height is adjustable with the turn level. I had to deflate the nose wheel to be able to level the airplane with the mains about 0.5" off of the ground. It may be different if you do this section with the engine mounted. One thing is for sure, you don't want to do this with the wings mounted.

Your objective is to get the wheel fairing pitch and yaw axis aligned with the longitudinal access of the airplane in it's flight attitude. The roll axis of the fairing is aligned to the tire. Now this may fall into the category of measure with a micrometer, mark with a crayon and cut with an axe, but the procedure is to transfer the center line of the airplane to the floor with plumb lines, then measure the fore and aft tips of the wheel pant to this center line. The pitch is measured relative to the floor which should match the flight attitude level plane. The pant is then match drilled to the wheel brackets. The next step is the addition of fiberglass layers and flox to shore up the screw holes. After adding the flox, all the 0.5" screws provided with the kit were too short. You will need to order MS24693C52, 54 and 56's.

I added doors to the sides of the main wheel pants to provide access for airing the tires. Details of how to add the doors is here on my Wheel Door page.

Jacked & Leveled

Initial Fit

Next step is addition of the leg fairings. The plans are clearly wrong in stating that the flight line is from the fairing to the step. The flight line is actually from the fairing to the same height above the floor at the step. Not that my alignment string is to a point below the step contrary to the drawing in the plans. The leg fairing comes pretty long and you can trim at least an inch from each end before adding the hinge. Also the template does not cut the inside of the top shorter like it does on the bottom. Taking another 0.5" off here helps with the fit too.

The intersection fairings come pretty thin and the plans have you add two layers to the parts. I added the layers to the lower while on the airplane but did the upper off of the airplane. I'm actually getting pretty average at fiberglass work and was able to add the layers with minimal sanding required. After the pieces are trimmed to size, I will coat them in superfil for the almost final finish. The last step will be to cover them with Smooth Prime to fill the pin holes. The upper fairing is supposed to be mounted with sheet metal screws into the fuselage bottom skin. Be careful of where you drill! I am going to use nutplate where ever I can and minimize sheet metal screws.

Leg Fairing Positioned

Intersection Fairing

The plans don't specify the orientation of the airframe while fitting the nose wheel fairing. So I let it down off of the jacks and tail stand. The plans only show a "non-deflected" tire in the drawing and the airplane naturally has no pressure on the nose wheel with no engine. As I fit the nose fairing, I noticed that my fairing would be positioned further forward than shown in the plans. I double checked everything and could not account for the difference. Finally, I decided to put the airplane back up on jacks, way higher than before to get the nose wheel up and then relevel. Although a good work out, it didn't make any difference in the position of the nose fairing. So my fairing is probably a little longer than what is shown in the drawings or the drawings are incorrect. Other than the alignment, mounting of the fairing is very similar to the main wheel fairings except that it is a tighter fit. When it came time to add flox in between the bracket and fairing, I squeezed in what I could and then removed the fairing after it cured and finish it on the workbench.

The leg fairing was trimmed about 0.5" shorter in length than described in the plans. I also had to remove a considerable amount of material from the lower front to get a good fit to the nose wheel pant. I then swung the nose wheel side to side and trimmed some more to eliminated any rubbing. When I was done I had a little larger gap than I would like but I think it is OK.

Nosewheel Fairing

I finished the fairings with Polyfiber Smooth Prime. I thinned it 20% and then sprayed on a thin coat. You want to thin enough to spray but not too thin or it will run. If it runs you have more sanding and work to do. The first coat highlighted the pin holes. Then using a bondo applicator, I forced unthinned Smooth Prime into the pin holes. Then applied a couple of more coats, sanded, and then a couple of more coats until final sand. It is very time consuming but it is done, it looks great and I am on to other things.

All dressed up.

Smooth Primed

Note From The Future: When you cut the openings in the wheel fairings for the tire, don't just do it for the fully inflated tire. You need to account for flexing of the tire in landing or a tire low on air or even a flat tire. I think a 0.75" gap is more appropriate than what is called for in the plans.

6/18 to 6/2610

15 hrs

Sec 49

Seats and Belts
The pilot and copilot belts and harnesses are 1.75" wide, Camloc release, racing harnesses sold by Crowe Enterprizes., The harness mounts at 3 points using a 0.5" hole at the cabin top and 0.313" hole for the lap belts. The lap belts require a bushing to the 0.250 mounting bolt. The shoulder harness required a bushing to the NAS-516 screw and a AN970 washer. I used a smaller AN970 washer and then drilled the ID larger to get the correct ID and OD that I needed.

To create an overhead harness holder, I first made a forming die. The forming die was made from 0.5" plate and machined down 0.25" and corner rounded 3/32". I then put the sheet metal in the die and squeezed in a vice. That made the double jongle in the holder. I then bent the ends up further to make that tab under which you slip the belt.

Forming Die.

Harness Holder

I decided to not install shoulder harnesses in the rear seats. Instead I bought auto style seat belts with a Davis style lift latch. When I built the baggage floor, I added four 1/4 -32 nut plates for tie downs. McMaster Carr had the exact tie strap, 8834T62, that I needed. It has a 1" wide strap, 6' long, with quick release and bolt down ends. With the addition of a bushing and a AN970 washer these load straps mount to the baggage tie down points. I've done all the fabrication work but won't actually install the harnesses, belts and straps until I am finished climbing around in the interior.


1 hrs

Sec 50

Cabin Heat
The Defroster Fiasco

After mounting my fuel selector up high and then relocating the fuel filter for easy maintenance(see firewall forward, EIS), I concluded that it is impossible to get a scat tube to the rear heat vents. I've had my mind on windshield defrosters all along and decided to use the second firewall heat take off for that purpose. I bought a 2" flange to mount inside the tunnel and a 1" flange to mount outside the tunnel to act as a reducer and conduit for moving heat. I then bought tiny nozzles to act as defrost vents. All sounded good until I set the windshield on the upper forward fuselage yesterday for a test fit and found that there is no room for nozzles, and no area aft of the subpanel that is below the windshield. So this did not work out at all. I am going to go with a passive vent above the radio stack and maybe another above the EFIS for symmetry.

Since I have no use for the second heat take-off on the firewall, first thought was to remove it and replace it with a cover plate. Then I found that I did a pretty good job sealing it to the firewall and it is impossible to move. So I just safety wired it in place. Then a funny thing happened, a RV-10 exploded after landing when the pilot retracted his flaps with a fuel leak in the center tunnel. That is when I came up with the idea to just route ram air from the left air dam directly to the firewall flapper. This allows me to clear the center tunnel with fresh air if I think I it is needed. The left muffler has no heat shroud on it. So cabin heat is only provided to the front vents from the right muffler.

Mike Andresen
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Last update 23Jun2011