Pirep on Summit Skis

On any ski installation, I MUCH prefer the front cables attach at the engine mount/firewall, as opposed to the landing gear.

MTV

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I’ve noticed Summit uses the cable attach points on the landing gear, what is the advantage to mounting cables to the firewall/engine mount? Is it purely geometry? If you stick the plane in snow is there any more of a chance to mess up your engine mount/firewall when cables are attached?

Thanks.

Schwarz said:

I’ve noticed Summit uses the cable attach points on the landing gear, what is the advantage to mounting cables to the firewall/engine mount? Is it purely geometry? If you stick the plane in snow is there any more of a chance to mess up your engine mount/firewall when cables are attached?

Thanks.

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I doubt you'd break the engine mounting. But, it's all about the geometry. That forward LIMIT cable is there to prevent the ski from "going over", ie: rotating nose down to the inverted, if the aft limit cable and bungees were to break. Yes, I realize that's a real stretch....pun intended, but **** happens on skis.

So, with the forward limit cable attached to the main gear attach bolt, the angle is pretty obtuse between the cable and ski. That cable has to be a little "tighter", ie: less slack, than if it were attached to the engine mount. With more slack, the ski floats over irregularities better. And, there's almost no chance it'll go over.

MTV

Thank you MTV.

Plus, and I know this from the crane rigging I do, at a 30 degree angle you lose half the breaking strength of a sling, an angle just torques on everything more. T he same holds true for cable/wire rope. My rigging has load capacities right on it, straight up and down is the highest, and as you angle it the rated capacity drops. I would have used my motor mount bolts on My S-7S/Datum combo, but my radiator was in the way! But I found a strong point on the side of the cowl, right close to the firewall, that works great, giving me the more desired near vertical load path.

Schwarz, If you're the guy that just brought an experimental SC up from Texas and has it in Bemidji, hello. I was talking to a buddy a couple of days ago and he mentioned a TX SC wanting skis.

I have a set of Datums, although not for a SC sized plane. I have 2000 LITE but you are welcome to look at them to get an idea of how they are constructed. Funny, as I just brought one to another friend, who is finishing up a SC build. He wanted to look at them to see if that is what he wants to buy. I believe he made up his mind after seeing them.
We weighed 3 different types for his reference, since he wants light weight but still have the ability to taxing on a regular runway.

If interested send me a PM. I'm south of Bemidji but get up that way occasionally.
Keith

I have TrickAir skis on a 120hp Taylorcraft and yes they are a compromise. Never had a problem getting airborne but if the snow is deep, I always makes tracks or go back over my tracks just to pack down the snow. Well built skis, easy on/off, custom mount needed, field approved 6 years ago, bungees attached to the motor mount.

Bearhawk Builder said:

I'm in, where do we start. I've never gone through the process.
I assume the engineering needs to be looked at, is it a matter of getting drawings from Summit? Will prior field approvals be helpful?

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Pm me or email n14ky@aol.com


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