Tell us what you did today on your Bearhawk Project

[alaskabearhawk]

One of the final steps is finishing the wing root trim. I used gray Kydex to match the interior color. It’s very easy to work with, but it’s not cheap! The color isn’t exact, but pretty darn close. This is the exciting bit. Once all my trim pieces are painted, it will be time to take off the wings and transport the whole kit and caboodle to the airport for final assembly. I also put some stickers on the outside of the door to show how to move the lever.

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[Nev]

Looks great. Just in case you haven't discovered it, Kydex bonds really well using the adhesive for gluing plastic plumbing.

[alaskabearhawk]

That's good to know Nev. Reading their product info on their website makes it sound like you need some real exotic stuff to do the job.

[Nev]

The label says it's for uPVC systems. Dries overnight. Once dry it doesn't let go.

[Bcone1381]

I've been building the engine cowl. I split the lower cowl because managing a smaller aluminum sheets made it very easy for working alone in the shop. Bob calls out 10 AN470AD-4 rivets on the lower cowl. I used almost 20 soft (AN426A-4 (no D))and liked how the soft rivet rivets interface with teh fiberglass nose bowl. A washer for a #4 machine screw is set with the rivet for reinforcing the fiberglass against the rivets inside shop head.
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I am using Piper style cowl latches. These latches are adjustable and I like how the pull the entire cowl together. The latch has three parts, I call it the hook, the Latch, and the fastener. The Hook is set in the lower cowl on the left side. The bottom of the door is oversized and get trimmed later after the latches are installed. The door will also have a 3/4 angle inside that runs along the bottom. I may also add a stiffener so the door keeps its shape when opened. Its quit floppy right now.

In my next build sessions I will be setting hooks on the right door then the latches in the upper cowl door.

In the second photo the hook is held in place with clecos. the next shot shows the hook from inside the cowl.


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[DBeaulieu]

Looks good!!

[jaredyates]

Not to rub it in, but today my dad was in town so we flew around in our Bearhawk to run some errands.

I'll tell you the story not because it's especially remarkable but rather as a case study for what the Bearhawk is good for and why it is such a nice plane to operate, and hopefully provide some motivation if you are still building.

One of my local friends purchased a small airport around 20 Bearhawk minutes away that has been in operation since the 1930s, and we were overdue for going to visit him. He has a new hangar and a house under construction, and we were scoping out his construction details and catching up. We are also constructing a large building and learning as we go, so visits to other friends who have already figured things out are especially fruitful. On the way up there we were around 1000 feet AGL with a tailwind of around 15 knots. I set 8 GPH (around 20 inches and 2000 RPM) and that yielded around 105 knots indicated. This is our usual loafing power setting, and the Dynon figured it was 48% power. Oil temps were a little low at around 155. I've ordered parts to build an adjustable baffle for the oil cooler to try and raise the winter temps. If it works, I'll elaborate.

From there we flew another 20 Bearhawk minutes to visit a famous Bearhawk alumni to scout out some construction details on his building (which is made by the same company as ours, which makes it even more useful to visit) and also to catch up, and to see his new airplane project. For this leg we were southbound (upwind) so I bumped up the manifold pressure to 22.5 inches, still 2000 RPM, and this yielded around 9GPH and 115 knots indicated. (all of these numbers are slightly approximate, but you get the idea).

At the beginning of the day, our local paved airport TAF was calling for steady winds from the south at around 7mph, with no gusts all day. The big airline airport to the south had a forecast for about the same steady wind, but added gusts to 19. Even with gusts like that, it's not no-go territory, but I wouldn't take non-pilot people for rides. Not a big deal in this case.

By the time we were done with all of that visiting and ready to land back at the cozy little airport where the plane sleeps, it was around 2pm with the usual mid-day bumpy conditions. Nobody got sick but if the kids had been with us they would have been complaining. Thankfully they were at school. We always land northbound because the runway is on a fairly steep hill, but the winds were from around 210 degrees. The runway is in a slot of trees, so strong surface winds make for additional turbulence from treetop level to the surface.

These conditions drove me to two mitigations. The first is that any time surface winds are strong, I carry extra speed through the tree slot on final. Instead of 65 knots on base and 55-60 through the slot, I carry the 65 all the way through. This ensures extra energy is available to handle the swirling winds and the flare. The Bearhawk has excellent control authority at 60, but at 65 it has even more. Unfortunately, this also means that I would be accepting some risk by going faster with a tailwind.

The second mitigation, because of the tailwind, was to intentionally enter the base and final with less altitude than I would in calm conditions. The wind would be adding energy, so I needed to arrive on final with less. I could have done this and still been on a power-off glide ratio to the runway, but that wouldn't leave me any margin for error or for wind change. Instead I was intentionally below a power-off glide to the runway, which is also accepting some risk. If the strong winds had been headwinds, I would have positioned myself higher than normal which would have been a more natural sight picture. Accepting some additional risk is part of the equation in operating out of the place that we do. But our home airport is still longer than Bob's! This is exactly the kind of flying the plane was designed to do.

For the landing, I used the third notch of flaps. All flaps generate lift and drag, but the Bearhawk flaps are especially good at drag. This allows for steeper approaches. With a strong tailwind aloft, having that steeper approach angle through the air really makes a difference in the resulting glide path through space, even though that end result glide path didn't end up looking all that steep because of the wind. I haven't downloaded the EFIS data to see what our ground speed was coming through the tree slot, but it was swift. In calm conditions, I use about 600 feet of runway to roll to a stop, usually with no braking. Today it was closer to 1200, with some braking. That left 600 feet of additional unused runway margin for stopping. We had excellent stick and rudder authority all the way to touchdown, and plenty of energy available for the flare. After we landed I checked the METAR for the civilized airport 5 miles away, and it said the winds were 210@15 gusting 28, with the highest recorded gust in the hour at 31 knots. The TAF had been updated to show gusts to 17 knots. Thanks weather guys for trying, if not for succeeding, in getting the forecast close!

I'd not usually set out to operate in these kind of conditions, but the Bearhawk can certainly handle them, with a little practice.

The first stop:
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[Nev]

Interesting and enjoyable read thanks Jared.

[DBeaulieu]

Got my elevator trim rigged and made a makeshift seat (temporary) so I can figure out my rudder/brake pedal positioning.

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[jaredyates]

Got my elevator trim rigged and made a makeshift seat (temporary) so I can figure out my rudder/brake pedal positioning.

We don't want to think of positioning the rudder pedals as a builder preference customization. Their location is depicted on the plans and deviations from that location have led to some problems including possible jams.

More about this:

https://bearhawkforums.com/forum/bearhawk-4-place-plans-build/1100-rudder-pedal-placement

[DBeaulieu]

Thanks Jared, to clarify what I meant...I needed the seating positioned so I could start making up the rudder cable lengths and get a sense for the rudder/brake pedal range and setup. (also to reassure myself I could reach them LOL) Not planning on relocating them on the fuselage. Dave

[DBeaulieu]

Got my top formers, right side window frame and baggage door formers riveted in. Started to fit the skin of the baggage door as well.

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[Dpearson]

Got the pitot mast mount sorted out.

[rv8bldr]

Sloooowwwly working on my fiberglass parts. I HATE working on fiberglass (actually, it's the repetitious fill/sand process that I hate). The past few days I've been making my nav/strobe fairings for the wingtips. Turned out pretty well although I do have a few more rounds of fill/sand before the tips are ready for paint...

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[Aero_tango]

Looks very nice…looking forward to see the green colour end result…

[DBeaulieu]

THIS...is my next big learning curve! I'm a zero-time fiberglass student and I'm envious. Those do look nice.

[DBeaulieu]

Got the door formers riveted in and nutplated the forward vertical former which underlaps the boot cowl. Then proceeded to do an initial fitment and skinning of the door.

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[DBeaulieu]

Cut plexi for the front windows, did initial fit and marking for Lexan skylight, cut front half of pilot door skins to add lower side view window. I learned today that Lexan can be cut with a shear. Will see how that goes tomorrow

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[RobinDeMarco]

I've been a little lax in posting this, but I have officially started my build. Over the past few weeks I have been doing a bunch of woodworking. At this point I have a set of cutting forms and I am working on the forming blocks for the wings. It's not much, but it's the first step of a long journey. May the fun continue.

[SpruceForest]

Another scratch-builder! Three cheers for our particular brand of crazy! Looking good!

Having buried myself in MDF work for weeks as you are doing, I really enjoyed the process. One thing I wish I would have done before finalize those forming blocks and pressing/flow-forming up all my nose, center, flap, and aileron ribs was to bend the spars and tweak the flanges (hint: Fairmont MT114030 tongs... Cleaveland sells them, or your local sheet metal tool supply). Between adding joggles after the fact on the center wing ribs (was going to forego that, but thought better of it after seeing how unforgiving 0.020 skin can be) and variation seen in pressed versus flow-formed rib flanges, being able to tweak the forms for good fit would have saved me some time. Expect to have to further tweak for best fit, but you'll avoid wholesale rework and the potential for work-hardening/cracking stuff.

Also - having all of the jig pin locations in the master rib was really helpful in ensuring uniformity of those various templates, lightening hole press blocks, and forming blocks. I did not find need to do drill bushings for them, but not a bad idea.

[Paul Johnston]

That’s great-I always do the wings first- if you have the wings,then you know you’re going flying. If that makes sense.

[Chewie]

Congrats Robin!
When it comes time to forming aluminum, don't do what I did. The first ribs I formed were the main nose ribs, and with that tight upper curve they proved to be the toughest. Start with something simpler or straighter like the flap ribs to get your process down.

[DBeaulieu]

Had a productive week doing skylight lexan fit, window plexi cut/smoothed/installed into one window frame, and did long rudder cables from rear pedal to rudder horn.
Planning on fabricating a nutplate strip to fit in the square upper skylight formers to attach sides of the skylight - think the plan will work and I won't have to do nutserts.
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[alaskabearhawk]

If you hadn't done so already, now would be a good time to make a template out of posterboard to show where your cables would exit the fuselage fabric enroute to the rudder horn. The future me found it was worth it's weight in gold when the time came to poke a hole in my brand new fuselage fabric.

[DBeaulieu]

Good idea...thanks!

[DBeaulieu]

Continued working on cable retainers for the flap cable pulleys

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[alaskabearhawk]

Those need to be redone! Please see my response on the Cable Retainers.

[DBeaulieu]

PM sent to you alaska...

[rkennell]

filedata/fetch?id=89368&d=1712322271&type=thumb Somehow, getting the wings buttoned up on a quick build assemble seems like a bit of a milestone. When a a friend like Dean, who is a scratch build addict (Mustang II, Wag-Aero clipped wing Cub), tutors and helps you on how to correctly buck rivets it makes for educational and wonderful time.

[gregc]

Finally got the fuselage out of the paint booth and the wings in.

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