BEARHAWK Project Pictures

These are the pictures I have so far...The lighting kind of sucks but so far they've turned out okay.

Posted 5/8/98

My wing rib form block
A wing nose rib
An aileron rib
A wing back rib

Posted 7/29/98

A wing tip rib
An .025 center rib

Posted 9/9/98

A flap rib
A bunch of rib stiffeners

Posted 10/23/98

Gluing up oak to make form bocks for the little ribs
A pair of flap nose ribs
A pair of aileron nose ribs
An aileron nose rib in the simple but effective drilling jig
A pair of aileron pocket ribs
A hydraulic press I built to bend steel fittings, among other things.
Close up of the press mechanism

Posted 11/30/98

An .032 center rib
One of the short ribs between the rear spar and the so-called "false spar" behind the fuel tank bay.
Cutting the weird shaped lightening holes in the center (and short) ribs using the Malco Hole Cutter.
A complete set of wing, flap, and aileron ribs for the Barrows Bearhawk.
The best tool stand ever made, also the best use for a dead drill press. I have been using it with my excellent new Grizzly sander.

Posted 01/20/99

Match drilling the strut attach plates. I first drilled the bolt holes 1/32 undersize, and finished with a chucking reamer. The resulting bolt holes are as close to perfect as I could make them.
A die I made for forming brackets out of .080 4130. I made a similar die for the .063 pieces, thanks go to Pat Fagan for the idea.
Die, press, and workpiece ready to bend.
Bending 4130 in the press die.
Removing springback in the bench vise.
After forming, the back of the fitting is bowed slightly. This is not acceptable since it should have a flat mating surface where it bolts to the spar. I removed the bow by placing it in the die upside down and carefully pressing it out.

Posted 07/20/99

Here is another die I made for bending 90 degree fittings out of 4130 in my hydraulic press.
The male portion of the die, made from a piece of heavy steel strap that was laying around the shop. It is radiused to bend .063 4130, but for doing thicker stock I can add thin sheet to increase the radius.
For the slower students, this picture shows how the 2 pieces fit together.
Some of the control hinge pieces I have made using the die.

Posted 08/08/99

As requested, a couple of pictures showing the bend radius I got using my die. Here is a closeup and a not so closeup.

Posted 7/09/0

Here is a picture of the flap arms, which are the last pieces I finished before I had to stop building for about 3 years.

Posted 1/31/03

The finished aileron hinge mounts, ready for the rod end bearing$.
Flap hinge mounts, tack welded and ready for fitting. Once the flaps have been fitted to the wings, these will be finish welded (in case I have to break the tacks to adjust the flaps).
The jigs I constructed to weld the hinge mounts
The finished wing strut links. These turned out to be less hassle than expected.

Posted 6/25/03

The aileron support frames. The forward mount point is for a pulley, while the rear point supports the bellcrank, which actuates the aileron via a pushrod.
The flap support frames. Note that the bearings for the torque tube still need to be welded into place. Rather than build an elaborate jig to ensure the correct alignment of these pieces (at least one builder has still had to cut and re-weld this even using a jig), I am waiting until initial assembly of the wings before tack welding these pieces. Between the use of heat sink putty and the concentrated heat of my TIG welder (vs. oxy acetylene) I will be able to do this without affecting the heat treatment of the adjacent aluminum parts. Once the parts are tacked in place, the support frames will be removed for finish welding.
Flap and aileron pushrods. I wasn't able to find the specified "heavy nuts" shown on the plans, so I used coupling nuts cut in half, which gives over 3/8" of thread length. A phone call to designer Bob Barrows confirmed that this will be strong enough even though the coupling nuts are mild steel.

This is the completed rudder and brake pedal assembly. I made 2 deviations from the plans here. Most visible is the addition of brakes for the right side, while somewhat less noticible are the .050 tabs welded onto the ends of each rudder pedal to keep my feet from sliding off to the side. The tabs at the top of the picture will be welded to the fuselage frame and hold the lower end of the brake master cylinders.
The rudder pedals without the toe brake pedals.
A close up of the left side rudder pedals.
The toe brake pedals.

Posted 7/15/03

The elevator bellcrank.

Posted 7/20/03

The control sticks. Picture these with ATV handlebar grips and a push to talk button at the end.
The stick tower assembly and push/pull rod. I had to make the towers from 2 separate pieces of .063 4130 because my press brake couldn't do both inner bends. Thanks to the TIG and a skip welding sequence I was able to join the pieces without any distortion.
The completed control stick assembly; for obvious reasons the temporary hardware will be replaced with AN hardware prior to final assembly... Now all I need is a fuselage to sit in and make airplane noises.

Posted 7/26/03

One of the outboard fuel tanks in the "porcupine" stage. After riveting together, all seams and rivets will be welded up, and inlet/outlet/vent flanges will be added. I decided to build the smaller tanks (11 gal each) before the main tanks (27 gal each) because 1) they are easier, 2) my mini brake can just barely form the skins, and 3) I ran out of material to finish the mains. I have to find a better brake and buy more material but building these first bought me some time.

Posted 8/5/03

After much pondering, I decided to get fancy with my vent fittings. I liked Russ Erb's idea of running a hard line inside the tank from the highest point to an exit, but didn't want the lines sticking out of the tank where they would be a target for damage (more of an issue during construction than in service). So I routed the line to the vent location shown on the plans, and welded a 3/8" NPT threaded fitting over it. Here you can see the end of the line flared to fit in the depression created by beating the end rib with a rounded punch. I used fabricated clips to hold the lines to the tank interior. Relying on only the rivets to hold the clips on for welding turned out to be a really dumb idea leading to much drilling out of rivets when the clips popped free during welding. At least I had the good sense to do the vent welding FIRST. I wound up welding the clips to the inside of the tank skins.

Here is one of the tanks riveted together. I used MS20470A4-5 (soft) rivets wherever possible, but still needed a lot of 1/8" hardware store rivets to close up the tanks (especially after having to drill them all out... grrr). After some practice welding of aluminum scrap, I eventually reached the point where there was still room for improvement, but more practice would have just been postponing the inevitable. This is the first tank I welded up. I got some distortion but since it is going to be hanging in straps and concealed from view, I'm not real concerned about it. The filler flange will have to wait until I choose what type of cap I will use. This will be partially dictated by my eventual engine choice (Jet-A nozzles and caps are larger than gasoline fueling equipment to avoid mixups).

Since I had a big chunk of 6061-T6 round in the scrap pile, I made my own threaded fittings. They are a little fatter than the standard item but I've personally removed and sent off for repair a Citabria tank with a cracked threaded fitting. I've got no desire to ever repeat that experience. I made the vent fittings using the same 3/8" NPT tap as the outlets, although 1/4" probably would have sufficed. Here is a view of the 1/8" NPT fitting for the quick drain.

Update: Astute observers may notice that I screwed up my aux tanks by making them the same shape as the main tanks should be. This fact was subsequently brought to my attention, and there was much swearing and gnashing of teeth. They were actually supposed to be several inches longer at the rear since there is no false spar in the auxiliary tank bays. I have modified my tanks to the correct shape but haven't taken any new pictures of them as yet.

Posted 2/13/04

I've postponed assembling the main tanks for lack of a suitable brake for the time being. I've purchased a 4' brake, but it still has to be shipped from Arizona to Alaska, so for now I am working on the wing structure again. Here is an .025" rib stiffener placed in the sophisticated matched hole tooling apparatus which ensures that all stiffeners of a given length will be interchangeable. Concurrently with drilling the stiffeners, I'm also making drilling guides for use in mounting the stiffeners to the ribs such that any stiffener will work with any rib once the holes are drilled. Since these parts will be assembled wet after priming with a thin layer of primer between parts and in the rivet holes for maximum corrosion protection (I plan to operate as a seaplane), using a matched hole system to create interchangeable parts will greatly simplify the priming process since there will be fewer unique parts to keep track of.

Posted 3/06/04

I cut these out a while ago, but have been spending time waiting for my next material order to arrive deburring and polishing the edges of the .125 spar plates. I drew the patterns for these in CAD, which were then cut out and stuck to the aluminum with spray adhesive. Here you can see how I got these all to fit on the 16"X36" sheet of 2024-T3 which I bought locally at Reeve's.

Posted 2/19/05

Shearing spar webs using my rolling shear. I left them a little big so that the flanges may be trimmed to correct width after bending. From the lack of recent pictures it may look like I haven't been doing much on the project, but I have been working on it some, just not taking many pictures.

Posted 3/08/05

Welding up one of the aileron bellcranks in a simple jig made from 1/4" steel.

Finished product. I'm really happy with how well these parts turned out, since the welding was a little tricky to get just the right amount of heat to ensure adequate penetration, without ruining the machined surfaces. Many thanks to my friend Wade Goodridge who did the machining for me.

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