Fuselage

Showplanes Fastback

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I had gone back and forth on whether or not to do a Showplanes Fastback conversion for some time. Last summer’s trip to Oshkosh sealed the deal. Today I took the plunge and ordered the kit. I’m told the lead time is approximately 8 weeks.

If you’d like to learn more about the kit, visit the Showplanes website here. 

So, why a Showplanes Fastback? What are the advantages? Who cares? As I said, I’d waffled on this decision for some time. Like many decisions there are pros and cons. For me the biggest positive is a clear unobstructed view while flying. I’m paying a lot of money, and I want a room with a view. You also need to keep in mind when building an RV that despite your best efforts you will not be unique. There are literally thousands of planes out there that bare an uncanny resemblance to your own, especially if you paint your plane in only primary colors or heaven forbid white. (Come on people… its not a Cessna)  With the fast back, at least you’re a little unique!

Other positives include a better seal for drafty winter flying, access to the avionics area, and slightly enlarged rear baggage area. Negatives include a lack of protection from bird strikes, and cool factor during taxi. Opponents of the fastback will say they never notice the roll bar in front of them. And yes, its minor. (Again, money.. room with a view) Fans of the standard slider will also frequently say “But you can’t have your arm draped over the side like an old time fighter pilot as you taxi!” To which I simply reply, “I plan to spend more time flying than taxiing” An that, simply put, is all there is to say.

Fuselage 1 (5.0 hrs)

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While I still have work to do on the fuel tank, I decided it was high time I did some work to my fuselage! Quick-build fuselage construction begins on page 41 of the fuselage instructions and begins with mounting the gear. I will not mount it permanently at this time, but I will get everything match drilled and ready to go for when the time comes. I didn’t do any research on doing this before getting to the hangar, so it was slow progress and I quickly realized this is a substantial project.

The first step was to rotate the fuselage and then remove the gear access plates.

Next I found all the appropriate parts, removed their labels, and marked them accordingly.   

Here is the mounting point for the inside mounts on the gear towers.  

Next I needed to match drill the holes shown here. The rotating stand made this a breeze! 

I had to match drill the 804 inboard main gear attach brackets to each leg. First Van’s tells you to slightly round the corners to ensure a flat fit. This is rather unnecessary as the bevels are clean to begin with. Never the less I gave it a quick once-over. I ensured the brackets were firmly in place with a few light taps from my dead blow mallet and then I clamped it in place with the pictured c-clamps 

I carefully clamped, leveled and aligned the gear and bracket to the drill press. Use lots of Boelube!       

Next you use the inboard brackets to match drill the inboard wear plate to 7/16″. 

This is where things get tricky. Those gear legs are heavy, and attaching them with one bolt and only two hands… well lets say this. I was sweating profusely at the end! 

Now, the next step is where things get more… involved. I need to ensure the gear outboard edge is parallel to each other, and to the fuselage center line. Secondly, the gear should be perpendicular, that is to say, it should be equidistant from the tail. All of this is important for handling and toe angle down the line. The difficulty in my case is my rotisserie mount. I will likely need to remove the fuselage from the stand to complete the alignment. Never the less I played around with the Van’s method that calls for using four plumb-bobs and some measurement to accomplish this. There is an alternative method on VAF that calls for using some aluminum angle to accomplish this. I will likely take a look at both. This isn’t something to mess up! 

I also opened up the notches for the outer brackets in the skin. The quick build already had sizable notches, but they still needed to be increased. The Dremel made quick work of the project.  

Multiple Sessions (12.0 hrs)

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This post encompasses several projects over three sessions in the hangar. First up I needed to figure out a way to mount the tail of the fuselage to my rotisserie stand. The axis of rotation is offset from the center of the tail. There are a couple of options for how to mount. I decided to make a padded cradle for the tail. I wrapped a cotton towel around the tail with duct tape. Then I clamped some 2x4s around very tightly to get accurate measurements. A short while later I produced this: 

I didn’t take a good picture of the front mount in my previous session, so here is that. 

And here is the final product for the tail mount. You can see how the center of rotation is offset and how I padded the tail in the cradle. The entire stand is sturdy, but it still makes me nervous. Especially while in the rotated position, its hard to tell how much of a torquing moment may be applied to the engine mount connections or any part of the frame. To protect against any mishaps I will continue to use the adjustable saw horses underneath. Additionally, I have a friend who is giving me an adjustable motorcycle stand. I am going to use that to create a center support that can be adjusted for any position near the center of gravity.

  

Here is the Hangar 51 mascot showing off his handywork.

That’s not a blue bow. Its poop bags. Keeping it classy.   

Next up, it was time to attach and torque the non-leaking tank to the wing. The screws get between 12 and 15 inch pounds of torque. I used torque seal to mark the bolts that were attached to the z-brackets.     

A trick I learned a little while ago that is seriously awesome; use a small dab of valve grinding compound on the tip of a your philips head screwdriver to avoid “caming” out of the screw head. Works wonderfully.   

I borrowed Mike Bullock’s screw driver click type torque wrench thing-a-majig. Works well.

I double checked that it work with my inch-pound bicycle torque wrench and a philips socket.

  

Squire enjoyed sunbathing. It was a gorgeous Sunday. 

I also drilled the second line that will hold either the AOA line or the pitot line. I still have two ribs remaining. The two interior ribs to the wing walk doubler are rather difficult to get at. I stopped at Lowe’s on the way home and hopefully I have a solution.    

My final project for the weekend was to complete the wing access panels. First I mounted the skins on the wings and match drilled. Then I deburred and dimpled.  Then I used a technique that I only just learned. Instead of using standard AN426AD3-3.5 rivets which require dimpling both the skin and the nut plate I used NAS1097 Oops rivets with the reduced sized machine heads. These only require a small countersink that you can do with your demurring tool in a few extra passes. Not only is it much quicker, but I think it results in a cleaner and more properly aligned product. There is no reduction in strength either. The nut plates bear the load… the rivets just hold the nut plates in place to prevent rotation.

You can see the results here:

And the final products.