As you might have guessed the domain name is the same as my name and I am the one in the picture in the corner. I have been looking for a plane for quite a while now. I can't seem to find what I want and can afford. The ideal senario would be 2 airplanes, an Extra 300 and a Husky. Sadly, I cant even find a reasonable J3 Cub available.

The solution to this poblem would be for me to build my own airplane. I have looked at various kits and plans built planes and have settled on a DR-107, otherwise known as an IAC One Design for my first one. It may not be an Extra but it's a whole lot more affordable.

The DR-107 is a single seat aerobatic aircraft. It is a low wing monoplane with a specially designed symmetrical airfoil. It is a simple, conventional structure that has been designed by Dan Rihn, a professional aircraft engineer with a lot of experience in the aerobatic world.

The fuselage has a welded steel tube truss covered with aluminum from firewall to cockpit and fabric back to the tail. The tail surfaces are fabric covered and wire braced. The one piece wing is wood. The prototype is shown here:

With any luck mine will look and fly like this one within 2 years. I have to set a goal and this is an agressive one.<< MORE >>

The first order of business in building a plans built airplane is to set up the workshop. This is a good excuse to buy the things you have wanted but were being cheap about, like the Speedglas helmet, bending brake etc. So that is what I have done, plus built a 16 ft workbench, add more lights, distribute air, build tooling to profile the chrome-moly tubing and build a welding fixture for the fuselage. I expected this to take 4 weeks but it actually took 5. So much for my time estimates. Some of the tubing was cut to the Bill of Materials stated lengths, marked and sorted. The tubing is on the pegboard, it doesn't seem like much does it? This is probably the cleanest this workbench will ever be.

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Its been about a month since I last added anything here. I started welding the upper fuselage pieces together on the welding fixture.I started the measurements were from the firewall end of the fixture instead of the center of the first horizontal cross member. Yes I screwed up by not using the proper F.S. 0.00 reference. In my haste to get started I lost 8 hours of work.

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I have put about 150 hours of work into this project so far in the past 3 months. That does not include the background work of gathering information, ordering and picking up parts, redrawing sections in CAD to see details more clearly and setting up the workshop, etc.

That time however, does include building the welding fixture as well as screwing some things up and having to re-do them. I have around 40 hours of the 150 expended there.

I now have a fuselage tack welded together. Most of it anyway. The roll bar and a couple of diagonals need to be added, but it now looks like some progress is being made... finally!

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I am at the 200 hour point and the fuselage is welded and inspected. As I mentioned, it doesn't look much different now as compared to the 150 hr point by looking at a picture. A close inspection does show some difference.

An EAA Technical Counselor,  Richard Harrington stopped by at my request to see if I was doing things right, check the build etc.I received a thumbs up from him. There are times when you are too close to something to see clearly so his approval was good. I had also asked Frank to do a detailed visual inspection on the welds. An extra set of eyes is always a good thing.

I was concerned about kinking the tubing when bending it so I put the tubing in an extension spring for support. I held the spring in place by duct taping the ends to the tubing. I then bent the tubing with an EMT conduit bender. No kinks! I probably didn't have to use the spring, but for $10 it was cheap insurance. I have the springs for the smaller tubing for the tail and rudder so I will use then there as well.<< MORE >>

Its hard to believe it has been that long. Clear weather is finally coming into the northeast for the start of the season, practice sessions and competitions are being scheduled. It going to be a busy summer.

The roll bar and associated bracing has been welded in place along with the structure for the seat. The original welding fixture held the fuselage a little too high for comfort when adding the roll bar and interior pieces. The fixture was cut up to make a pair of rotating stands and they were attached to each end of the fuselage.

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The fuselage doesn't look a whole lot different from a distance than it did 100 hours ago. There have been a lot of small additions made to the fuselage. The mounting brackets for the longitudinal control system have been welded in. The seat and the seat back mounting brackets have also been welded in. The reinforcing plates in the landing gear area have been added. All of them important but none visually impressive. The biggest thing visually is the control stick assembly.

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It seems that the brackets and stuff is beginning to take up more time than the fuselage frame did. There are a lot of little items and they have to be positioned accurately. Obviously, the wing mounts have to be located correctly. A wing mount  gauge was fabricated. It is shown below holding the wing mounts in position for welding.

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After 500 hours of work, 1000 cubic feet of Argon and $1500 in chrome-molly tubing and sheet material the 68.5 pound DR-107 fuselage frame has been painted and hung from the rafters in the workshop. The horizontal stabilizer, control stick and other miscellaneous steel parts have also been painted.

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While the One Design plans are good, the copies leaves something to be desired. Then again maybe I am spoiled because I usually get prints directly off a plotter. Using the prints as a template for the wing profile was something I did not want to do. Couple than with the fact that my wood working tools consist of a skill saw and claw hammer and my woodworking experience is pretty slim, it did not make sense to me to build the wings from scratch. I ordered a 'Wing Kit' from Bill Scheunemann an I am very glad I did. His company is Precision Aero Marine and their website is www.precisionam.net He makes wing kits and spars for many different aircraft both certified and experimental. The kits are precision machined with CNC equipment and the quality is second to none. I can see why Dan Rihn highly recommends Bill's wing kit and I agree with him. The cost differential compared to the wood kit from Aircraft Spruce isn't all that great. Bill supplies all of the wood pieces for the wings and ailerons and they are precision machined. The Aircraft Spruce wood kit is as complete as the fuselage kits. This means you only get the basic components, you have to order more. Considering this and the time savings factored in, the added value from the Precision Aero Marine wing kit is a real bargain.

The wing skins and a long crate arrived with the wing kit. A complete laminated spar and hundreds of little parts already machined, some bagged and others still tacked to a backing board. I picked up the epoxy and miscellaneous paraphernalia necessary to glue all the pieces together at the local boat yard. The guy in the shop at the boat yard was fascinated with the wood wing project, offered advice and gave me his cell phone number but stopped short of offering to stop by and help. I found that snack bag clips make good gluing clamps for holding the cap strip to the thin plywood ribs. They are strong enough to hold the pieces in place but don't squeeze the glue out. The local dollar store (junk store) had a bunch so I bought all of them. I got about 160 for $20. I used most of them each time gluing the cap strips to the ribs one side at a time.

It took about 40 hours to trim and glue the cap strips to the ribs. I had taped the cap strips on one edge so I wouldn't get epoxy on it while gluing the adjacent edge to the rib. I want to glue bare wood to bare wood with fresh epoxy rather than gluing bare wood to older epoxy coated wood. While the masking and removal takes time, I believe the end result makes for a stronger bond. I also apply the epoxy to both surfaces before mating them. That may also be overkill but it makes me more confident about the joint.

I don't have any question about the bond strength of the epoxy. I managed to get some on the zipper of the tyvek coveralls I had on while applying it to the cap strips. I found this out a few hours later when I finished that gluing session. My folding razor knife was in my pocket, under the coveralls. Talk about feeling dumb. Then the mind begins to play tricks on you, like the little kid who gets all bundled up to play out in the snow and then decides he needs to use the potty. Have you ever tried to chew your way out of a tyvek suit? I have done other dumb things but not in the recent past.

Here is a stack of ribs with cap strips and corner braces attached. A picture of the dumb look on my face after gluing myself in the tyvek coveralls is not available.

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The last few entries have been short on pictures. I have also received a few questions so I will try to answer some of them here as well.

First off is the wing mount fixture. I usually work alone so it was built as a method to rotate the wing spar without dropping it. It is on wheels so it can be easily moved. I can set the spar level but as soon as I move the fixture it is no longer level. For this reason and because I don't want to apply any twisting force on the spar, the arms were intentionally sloppy, 3/8 hinge bolts into 7/16 holes. The fixture is made from 2x4 steel tubing left over from the original welding fixture. The arms are 1x3 tube I just happen to have. The hinge area is shown here.

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There are a couple of things I forgot to mention in previous entries. One is an item that was very handy in removing the coating that is on the chrome moly tubing. When I was stripping the coating off for painting I began by using acetone and a scotchbrite pad. The scotchbrite loaded up very quickly. I then found a fine 180 grit open mesh sanding medium. It looks like window screen with grit bonded to it. This worked great for the first pass taking the bulk of the coating off the tubing. As it loaded up the stripped off materal just fell out of the sanding cloth. The followup was with the scotchbrite. Acetone does help but it is very nasty stuff, it can go right through your skin. It is also extremely flammable. I found the open mesh cloth in rolls in the plumbing section of the local building supply store.

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Its been about a year since I ordered the plan set for this project and just under 11 months since I cut the first piece of material to build it. All in all I have 700 man hours of labor invested, not including the time spent head scratching. Now that the cold weather is moving in, I did take the time this last month to build a pair of insulated workshop doors that don't leak. I also made a 14 ft by 28 ft tent frame 16 ft high from schedule 40 pipe and placed large tarps over it. This will give me a space to set up the fuselage and wing in alignment to install the wing bushings. The tent butts up to the workshop doors and it will be heated separately as needed. As a result of the time spent on workshop modifications there isn't a lot to show here except this:

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It is again time for miscellaneous pieces to be made that are required but are not visually impressive in this blog. There was an ice storm here a few weeks ago which caused a loss of electrical power for about a week. Mother Nature was being a bitch again. My generator powers the house but doesn't have the capacity to reliably power the shop at the same time. Oh well, with the holidays, I needed a break anyway.

The aileron bellcranks are made from chromoly along with their mounting brackets. The plans show the bellcrank mounting brackets made from two pieces, I made each of them from one piece of T shaped flat stock. Circular corner reliefs were used to eliminate any stress cracks starting from the inside corners. The reliefs are visible in the following picture. You may have seen circular reliefs in the battery mounting bracket in a previous entry.

The next item is the pitot tube base. I could not see the nylon tubing reliably staying in a wood block as shown in the plans and a compression fitting probably won't hold in wood much better. I made the base out of acetel, trade name Delrin. It comes in various temperature ratings. If you use it be sure to select the appropiately rated one. There is also a hole in the base on the far side of the fitting which will be used to pass a small electrical conduit through.

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The plans call for the ailerons to have 1/16 ply over the front and fabric over the rear surfaces. The Scheunemann wing kit comes with 1/16 ply for the entire aileron surface. I like that idea but the down side is that it will require more weight to mass balance the ailerons. The ailerons are required to be static balanced to avoid flutter at high speeds. The goal is to make them slightly nose heavy. It is better to be nose heavy than tail heavy with the ailerons.

There is a 3/8 inch slot cut into the back of the nose piece in the aileron to locate the added weight. The weight is generally lead shot and epoxy. The ailerons should be finished before they are balanced. The rule of thumb here is to add a weight to the front of the aileron until it is balanced and then add 10% more weight. The standard fabric covered aileron should require about 800 grams of weight, less than 2 pounds.

Plywood covered ailerons will require more weight to balance. One person with ply skinned ailerons mentioned that he ended up filling the slots and spade arms with lead shot to balance them. Lead shot and epoxy is not very dense. Lead rod would be much denser. The slot cut into the nose piece in the wing kit is 3/8 inch deep and 3/4 inch wide. I cut a 3/8 by 3/4 slot into the front aileron spar that the nose piece mounts to. This will allow me to use a 3/4 inch diameter balance weight. I will cast the lead into 3/4 inch diameter tubing and trim the weights to length as required.

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The hardware that is installed on and into the wings and ailerons is finally done. The spades and spade arms have been fabricated as well. As a result of the wing being tapered, the aileron hinge line is angled in reference to the wing spar. The spade arms are fabricated from steel streamline tubing. The arms have to be offset by 11 degrees so they are in line with the air stream passing  under the wings.

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I was at the point of adding the skins to the wings when I questioned whether the aileron control rods should be at the inner hinge or the middle hinge. I opted to move the control horn, spades and control rods to the middle hinge. I made a new bellcrank. The bearing housing was shortened to 2 inches and the arms were made from 3/4 inch 0.065 square tubing. The new bellcrank assembly is now located 2 ft further out on the wing. The lightening holes decrease in size as you move out the wing so I had to elongate the outer most hole a little to have free movement of the inner control rod. The inside rib also had to have the lightening hole elongated to allow the longer control rod to be installed freely. Here is the new bellcrank assembly clamped in position to verify the clearances.


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It seems that progress right now is going slower than I like, visible progress anyway. I installed 5/8 inch loom tubing into the wings to run electrical wires for lighting and other things at the wing tips. The size is overkill but the 5/8 inch tubing from Vans is the lowest cost, lightweight electrical conduit I was able to find. I had to make a new pitot tube base to hold the larger size tubing. It seems like I am making enough parts for 3 airplanes and discarding 2. Oh well, at least I am satisfied with the final ones.

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That's right, I have passed the 1000 hour point for hands on work on this project. There are actually a few hundred more if you count the background work, ordering parts, getting information etc. That part of the project is not being logged.

All of the detail stuff has to be done but there is no big visual impact. The plans show only one seat belt attachment point but two are necessary on each side. I contacted Scott at Hooker Custom Harness and was told that a 3 inch spacing for both belt attachment points is recommended so I added the extra bracket. The lower one is the additional tie point.

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That's right, the wings are finally ready to have the top skin put on. I put some extra wood inside where the pitot tube goes so it will hold the pitot tube assembly in 2 places place rather than just at the leading edge of the wing. The slots were made to pass the aileron control rods out. The openings were reinforced with some cutoff material from the stringers.

Hooker uses AN4 hardware to mount all 7 of the attachment points for the harness. The holes on the existing tie points were enlarged and the harness was installed to see if everything fit. The harness has the gel pads for comfort. The seat pan was fabricated, painted and installed as well.

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The construction work on the wing assembly is almost done. The top and bottom skins are installed. Here is a picture of the leading edge of the wing. Unfortunately the shop is not big enough to be able to back up far enough to take a picture of the entire wing, but the picture does show both skins attached.

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Fitting and aligning the wing has to be done accurately. The recommended method is to stand the fuselage on its nose and fit the wing assembly, align everything and pour epoxy around the wing bushings. It sounds pretty simple.

I typically work alone so I had to make some simple tools and fixtures to help in this part of the project. First off, the workshop ceiling is not high enough to stand the fuselage on its nose and the weather outside has been pretty crappy all year. A 16 ft high tent was setup to perform this task under.

The fuselage is around 70 pounds so it didn't pose much of a problem to move it into the tent. The wing assembly with the skins on is 160 pounds but it is long, so it is not east to move alone. I built a little cart to assist. The spar fits into the top and the cart fits in between the wings.


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