ski fittings

[arborite]

Tried searching but came up empty. Has anyone added fittings to their fuselage to attach ski cables? Or is this not a good idea on a BH?

[jaredyates]

kestrel I think has used skis?

[500AGL]

Typically they attach to the upper gear bolts, but on no a Bearhawk that angle is quite low. On the one I’m building and another I know of we have added a front spring attachment point near the top engine mount attachment cluster, aft of the firewall.

[arborite]

Typically they attach to the upper gear bolts, but on no a Bearhawk that angle is quite low. On the one I’m building and another I know of we have added a front spring attachment point near the top engine mount attachment cluster, aft of the firewall.

Thanks for the response. The top engine mount? Do you have a picture?

[500AGL]

[Alaskanf1]

Be sure to read AC43.13-2B, chapter 5, on ski installation (link below). I just got my Model 5 kit and haven't scoped out the specifics of how I'm going to attach yet. But, Super Cubs and airplanes with similar gear typically attach to the gear bolts and that works great. Sometimes people will run the front check cable to a tab on a lower engine mount bolt (longer bolts required) to have a secondary bolt in case a bolt fails. That also gives a better angle for the check (which needs to be stronger than the spring). The rear check cable can go to either the rear gear bolt (most common) or a float fitting attach point. My Cessna 180 had a tab bolted to the boot cowl up high just aft of the firewall where the spring cable attached (forward check cable was to tab on lower engine mount). The spring couldn't go to the lower engine mount tab because there wasn't room for the spring. While the high spring mount does provide a more optimal angle, it's a lot more work to put a mounting point up there, and it needs to be VERY strong. It also leaves a wart on the side of your boot cowl and is a potential paint scratcher. I've put skis on a lot of planes when I was working as an A&P and if the plane had gear bolts we used them.

BTW, Atlee Dodge ski springs are far superior to bungee cords. Look them up when you are ready for them.

https://www.faa.gov/documentlibrary/media/advisory_circular/ac%2043.13-2b.pdf

[alaskabearhawk]

Here are a few photos from Rob Taylor's BH ski installation. He used the rear seat front attach points as the rear check cable attach point.

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[Alaskanf1]

Those angles look fine to me. Note that 43.13 does give the minimum angles (angle "B" on figures 5-4 and 5-5). In the overview picture Paul provided, the rear float fitting is way too far back and the step on the gear is likely in the way of attaching the rear check cable to the rear gear bolt. So I can see why the extra fitting was added. Just make sure that fitting is very strong and is bolted into some good structure. There is an amazing amount of force that can be applied to the check cables.

[500AGL]

The angle issue is with wheel skis, or more to the point, retractable skis such as Datums. Using straight skis the gear bolts should be fine.

[Alaskanf1]

Agreed, retractable wheel skis are a whole different animal, and very manufacturer specific. If going this route, it would be ideal to pick skis out during the build so you can weld in hard points as needed.