Inertia reel mount location 4-place

[whee]

Where are you guys morning your inertia reels for your seat belts? I want 4-point belts in the front seats but I seems like the rear carry through tube to too close. Would be great to see what you guys have done.

[Chris In Milwaukee]

Dan Shilling in Alaska used a Jeep type reel. There's a video for it here (around 2:00):

https://m.youtube.com/watch?v=k-mNd71Bk3I

[whee]

Thanks Chris. Dan came up with some creative solutions that I think are pretty cool. I want to put my reel overhead like a BAS system.

[alaskabearhawk]

Just about have a solution worked out...stay tuned.

[N942VT]

I fabbed a crossover tube just in front of the carry through to mount the inertia reels on which puts them a couple inches farther forward but my seat is usually in the second hole from the front so the geometry seems to work well. Since you're welding anyway Whee, weld in a cross tube behind the carry through with tabs on it.

[alaskabearhawk]

Most are putting the inertia reel for the four-point shoulder harness on the rear spar carry through with a welded strap that wraps around it, or just a tab welded on and call it good. Maule Aircraft has something similar, but contrary to popular opinion their fuselage design is much different than the Bearhawk. I really think if it’s mounted this way, the angle is way too steep in relation to the body (per FAA guidance). There are other light aircraft that also have a steep angle, but I suspect the limitation is finding a place strong enough where they can mount the reel. But for my airplane to have the recommended geometry/angles for the shoulder harness the inertia reel needs to be mounted where there is no place to mount. With input from others, I devised this plan for the tubes for the inertia reel mount. The tubes are in tension, not compression. I’m not the best at computer drawings, but you get the idea.

Piper people (Mark Moyle for one) make a modification to their fuselages for a harness where the tubes are in tension, not compression, the main idea for my plan. (See the pics labeled Piper)

I took a couple of pictures of me sitting in the fuselage with where I want the reel and where it would sit on the aft spar carry through tube. I did some completely unscientific measurements with a protractor and a ruler on my computer screen. Measured from the top of the shoulder (like the AC) my reel location would bring the harness in around 30 degrees. The forward mounting point would put it just north of 50 degrees, but inline with my body.

After thinking about it and with all the input, this is what I am going with. Most all recommended designs regardless of type connect to an outside cluster somehow...cable, welded fittings, tubes, etc. The Piper pics that Mark had were the inspiration, and the attach point will have fingers that will cover the apex of the cluster. This will also keep the tubes in tension, not compression. There is more info on my Kitlog site and will be adding to it as the days go by.

[LukeS]

Paul,
Thanks for sharing your progress. I've saved quite a few pics from your kitlog site, and they're very helpful.

[whee]

I got my belts from Aero-Tuff and need to figure out where to mount them. I see your idea didn't work out Paul, any new ideas?

[alaskabearhawk]

Actually, I am working on Plan B but it will take awhile. I think this will work.

[whee]

I look forward to seeing what you do. I've got some other things to do before I work on my belt mounts.

[whee]

I look forward to seeing what you do. I've got some other things to do before I work on my belt mounts.

[alaskabearhawk]

Ok, I finally have installed my inertia reels in the BH. I had two plans, A and B. I ran both by my son who is an engineer for Boeing and by Bob Barrows. The verdict? Either would work. Plan B is the best option because the tubes are in tension. I went with plan A only because long ago I had welded in the T10 tube from the middle of the aft spar carry through forward to the X in the center of the cabin. That was a recommendation from Bob to install that tube if you mount your 4-point to the aft spar. When the tube was welded in that was the plan. Another reason is it is much easier to fabricate than plan B. If I had not welded in the center tube way back when I would have done plan B. Anyway, I am very satisfied with the installation. The angle of the harness is much better and the design keeps the reels above the headliner, below the fabric and out of the way of the passenger's skulls! Also. the consensus is if I am in a mishap and those tubes deform, there will be a LOT more bits and pieces bent, including me. So in essence it's a wash. YMMV (see the pics)

[rodsmith]

Looks real good Paul. Mine is similar but the Hooker inertial real is larger, I couldn't get it totally above the tubing. Real is only on pilots side for accessing the flap handle.

[alaskabearhawk]

Yeah. The AM-SAFE reel is the only way this works for me. I'm getting my harness from BAS and that's what they use.