Tell us what you did today on your Bearhawk Project

[James]

I was planning to put in the LH main tank today, but I discovered that one of the upper straps has been made too short, and my tank cover won't sit flush :-/
Luckily I inherited a lot of spare strap material, so it's time to make my first tank strap woo hoo!

It's been raining pretty hard here, so during showers I've been stuck inside planning the cockpit fit-out. Today I was researching the ICS wiring - I think I'll just make up 4 drop leads with TP-120 type plugs, and cable tie the leads to the fuselage. Easy to install, no panel-mounted sockets to vibrate loose, and saves me from having to manage two different headset jacks...

James

[svyolo]

You could also just cut the two verticals and extend them. It took me several tries to make a good strap.

[Pbruce]

I’m very new to building. I got my rotisserie made out of two engine stands, a couple of u-joints and some steel. It’s way overbuilt and cost way too much since I used a recommended welder who went overboard. (I can’t weld) I learned that cost control is an important element of home building and will keep things under my direct control from here on in.

The good news is that the rig works and I’m able to start installing components inside the wing now. 1AAA1897-454F-4BF1-B99B-488205355F54.jpeg

[svyolo]

Fabricating stuff like a rotisserie is a great way to learn or get better at welding. I cut my wing crates up and have used the metal for all kinds of fixtures, a wing rotiserrie made mostly out of the wing crates, and a fuselage rotisserie made out of two engine stands like you did.

I did quite a bit of Mig welding on exhausts years ago but always wanted to get better at welding. I wouldn't claim the title of "Welder" yet but I am a lot better than when I started.

[Chewie]

With nice weather this week, I took two days off work to prep and prime the aluminum flap and aileron parts. I used Stewarts ekoprime with a touch-up Finex spray gun and was very pleased with the results; they make a fine product. The finish is smooth and solid except for a few spots (mostly flanges that are hard to hit) that I need to touch up today. I ran out of room to lay out the spars and skins, they're next.

Hats off to you guys who can work on your build for 6-8 hours a day... I'm not used to this, it's exhausting!

[rodsmith]

Your ribs look factory made, nice job!

[Chewie]

Thanks! But I only show the good side on the internet. 😋

[Olm]

I'm on this step too and faced a question... what density Dacron or poly-fiber are you going to cover flaps/ailerons?

[Chewie]

Olm ,
Great question. I'm not entirely sure. The numbers I've seen are:
Stewart Systems: 0.8 oz/sf = 7.2 oz/sq yd
Bob: 0.1 lb/sf = 14.4 oz/sq yd
Realistic numbers from this forum: 10-20 oz/sq yd
Oratex...?

Obviously the finish and my skill level will play into it! I'm holding off balancing the ailerons as long as I can, maybe even after covering. What's your approach?

Edit: If you're asking just about the bare fabric... I'm not sure on that either. Need to research.

[JimParker256]

....
Oratex...?

From the https://betteraircraftfabric.com/common-questions.html page:

"Oratex600 weighs about 3 ounces per square yard." Since it is rated for use on airplanes up to 600 Kg (1323 lbs), so it would be appropriate for the LSA.
"Oratex6000 weighs about 4 ounces per square yard." This is the one for the rest of the Bearhawk fleet.

[Russellmn]

I wonder what the limiting factor on the weight rating is... since we're not using it to cover the wings, could we get away with it on the fuselage, since the stresses on the fabric there would be no different regardless of weight?

[Mark Goldberg]

When I was buying Oratex for my LSA, I did the calculation of how much more weight the 6000 was compared to the 600. I don't remember but thought the difference was small enough that I went with the heavier fabric. Mark

[Russellmn]

How about price difference???

[Olm]

Nice to see mere experienced guys are taking part in the discussion! I balanced my ailerons and without covering the weight is about 1,4 kg.(3,08 p) and thinking of leaving the hole in covering to be able to add some more weight into the balancing tube. We have in Russia Dacron poly for reasonable price it is 250 gr per m2(0,46 lb/yd2) and another 125 gr/m2 (0,23 lb/yd2). And to the theme, at the summer country-house begun assembling the flaps.

[Chewie]

Looking great! I had a question, I see that you are using attach angles on the nose ribs. My plan show flanges instead. Was that a change since your plans perhaps?

[Olm]

It was my decision on using angles. The plan is also telling to use flanges. I don't remember why it was done this way, because my nose ribs were done about 3 years ago.

[spinningwrench]

Today I machined a bezel for the pilots window out of .025" aluminum. I made it as a solid piece with some corner radiuses. I am going to pop rivet it to the window frame and sandwich a piece of .093" Plexiglas between the bezel and window frame. That will be my complete window system. I am not going to use bent up aluminum strips in the interior for backup as the window alone makes for a very rigid installation.

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[Bcone1381]

I really like little plywood pieces that fabricated to support the window frame tubing, the plexiglass and the bezel.

[spinningwrench]

The blocks have a 1/2 round slot to mate with the steel window frame and the edge of the jig gives the proper 1/2” bezel overlap on three sides and flush on the top. 2nd jig in the works for exactly drilling the tubes in dead center so the bezel will not be wonky when the rivers are put in

[Bcone1381]

I like jigs. Please show that one when you get it done.

[TimTall]

Today I test fit my exhaust system headers. I'm relieved that it fit perfectly. Clinton at Custom Aircraft Exhaust did a great job working from my hand sketched drawings to get it bang on!. There's not a lot of room in these cowlings for the IO-470! We managed to get 1" of clearance or more to every piece of structure, the cowling and the spark plug on the fwd left cylinder.

The tail pipes can wait until the engine is mounted in the airframe.

O-470 Bearhawk_Front.jpgO-470 Bearhawk_Left Exhaust.jpgO-470 Bearhawk_Top.jpgRight Side.jpgimage001.jpgimage004.jpgimage005.jpg

[Bdflies]

I hate to be "That Guy", but I’m probably going to be. I don’t see slip joints between the cylinders. Without provisions for cylinder movement, I'm leery.

Bill

[TimTall]

Don't worry about being that guy. That's why I posted here. I want opinions. There's seal-less slip joints at the connection to the tail pipe on both sides. Clint thinks that'll be enough. He's been building these for 40 years so I hope he's right. He definitely gave me some recommendations for how to secure the tailpipes to the airframe and to each other to avoid putting any torque back into the headers.

I'm not sure there would have been any room to have a typical slip joint in the header anyway.

[rodsmith]

Finally painted my floor boards with Stewarts acrylic metallic grey. Supposed to be pretty tough. I had made the floor boards a few years ago but was not happy with the fit of the most forward one, plus I had to move the fuel selector. So remade the front one and painted them. Weight of the .032 AL without paint was 12#-6oz. Paint added 8 oz. I may replace them with a carbon/kevlar laminate but not before I fly. Interior fabric paint is Stewarts Ekopoly, non metallic silver with flattener added to reduce the gloss, I like the way it turned out.
interior.jpg

[AKKen07]

That looks great Rod!

[svyolo]

I finally got around to starting the fuselage covering. I applied the fabric (Oratex) to the two upper sidewalls, and am almost done cutting the ceiling (aft of the skylight). Hopefully I will be done in 2-4 weeks, and hang the motor. A bunch of little super magnets really come in handyto hold the fabric in place

[JimParker256]

Great tip about the magnets! I would not have thought of that, but it's a really smart idea! I think I would avoid using them anywhere near the eventual compass mount location, however...

[Russellmn]

Syvolo, what do you think about the Oratex? I'm seriously considering using it on mine (when I get to that point) in a constant quest to add lightness.

Jim, I would be quite surprised to find that those little magnets could impart enough, or any, magnetism to the steel to alter a compass reading. Though I've been wrong before...

[spinningwrench]

Decided to take my Bearhawk out for fresh air today as I moved it to the airport. U-Haul auto movers have just the right wheel spacing for a Patrol. I had to rig up a wood structure to support the tail wheel as the trailer is 3’ short.
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[jaredyates]

We heard there was going to be a demolition close by, so we flew over to watch it. Then we flew to the produce stand for a load of melons, cucumbers, peaches, icecream and slushies.

[flashf16]

​ Not sure if this counts, but got the concrete poured for my hangar/workshop. Slowly but surely...

[Tim213]

I started up my Barrows O540 today and got the idle speed and mixture adjustment on the carb set. Even without a primer with the SureFly electronic ignition magneto the engine started right up which was a relief of course. The only issue was the Newton fuel selector valve was sticking and hard to switch to different positions. It was 104 degrees today in Southern Cal so that it’s hard to much done.

[svyolo]

Nice. Getting close.