spinner2
MEMBER
Montana
After recently rigging my Carbon Concepts board skis I Thought I'd share my technique and where I sourced materials.
Both my plane and the skis are not certified so I'm not bound by an STC or Field Approval. I made reference to both 43.13 and Dodge's online ski rigging tips. Both are very helpful.
The skis were received from Randy with pedestals but no rigging or attach points on the skis.
I purchased the toe and tail attach fittings from Stoddards along with stainless steel axle washers. The fittings that attach on the gear bolts and the bungees came from Reeve's.
I found some stainless steel clevis' with a high load rating from industrial supplier MSC that came with a 5/16" diameter pin.
The threaded half of the clevis is threaded 5/16-24 so I replaced the pin with and AN5 bolt and as a keeper threaded on an AN nut. The plastic donut is UHMW that I machined a 1/2" radius into and drilled 5/16" for the bolt to pass through.
On the gear attach point I used a Ronstan brand 6mm stainless steel, high load rated chain link. A hole was drilled though the hex section to accept a cotter key.
The second cable on the right is the check cable.
Setting the angles for ski movement was made easy using a chain hoist, comealong, and a smart level.
The first step is to set the length of the check cables. I went with a maximum down angle, should the bungee fail, of nine degrees. 43.13 allows for considerably more than this, but less seems better as long as there is enough slack to allow full ski movement over uneven ground.
The next step is setting the length of the rear cable. With the skis flat on the hangar floor I raised the rear of the plane with a comealong. I found that one click of the ratchet was equal to one tenth of a degree on the smart level with the placement I used.
I went with 1.5 degrees nose up ski attitude in flight. This meant raising the tail 1.5 degrees above level and the setting the rear cable to this length.
Lastly the the bungees are attached and the length of the crust cutter cable is determined by the amount of down force required to stretch the bungees. 43.13 has a poundage guide based on ski displacement. This step is a little subjective and not real easy to measure. But the end goal is to have enough tension on the skis through the bungees that there is no in-flight flutter of the skis.
The rigged skis weighed 33.2 pounds each. 1/8" diameter control cable was used per 43.13 for skis and a plane this size. After finding the center of balance for the rigged skis I made a new W&B. This is easy to do when existing component weights and arms are already in an Excel file.
A pair of Dolly's were fabricated too.
I'm sure there are other ways to accomplish the same results but this is how I rigged these skis.
Both my plane and the skis are not certified so I'm not bound by an STC or Field Approval. I made reference to both 43.13 and Dodge's online ski rigging tips. Both are very helpful.
The skis were received from Randy with pedestals but no rigging or attach points on the skis.
I purchased the toe and tail attach fittings from Stoddards along with stainless steel axle washers. The fittings that attach on the gear bolts and the bungees came from Reeve's.
I found some stainless steel clevis' with a high load rating from industrial supplier MSC that came with a 5/16" diameter pin.
The threaded half of the clevis is threaded 5/16-24 so I replaced the pin with and AN5 bolt and as a keeper threaded on an AN nut. The plastic donut is UHMW that I machined a 1/2" radius into and drilled 5/16" for the bolt to pass through.
On the gear attach point I used a Ronstan brand 6mm stainless steel, high load rated chain link. A hole was drilled though the hex section to accept a cotter key.
The second cable on the right is the check cable.
Setting the angles for ski movement was made easy using a chain hoist, comealong, and a smart level.
The first step is to set the length of the check cables. I went with a maximum down angle, should the bungee fail, of nine degrees. 43.13 allows for considerably more than this, but less seems better as long as there is enough slack to allow full ski movement over uneven ground.
The next step is setting the length of the rear cable. With the skis flat on the hangar floor I raised the rear of the plane with a comealong. I found that one click of the ratchet was equal to one tenth of a degree on the smart level with the placement I used.
I went with 1.5 degrees nose up ski attitude in flight. This meant raising the tail 1.5 degrees above level and the setting the rear cable to this length.
Lastly the the bungees are attached and the length of the crust cutter cable is determined by the amount of down force required to stretch the bungees. 43.13 has a poundage guide based on ski displacement. This step is a little subjective and not real easy to measure. But the end goal is to have enough tension on the skis through the bungees that there is no in-flight flutter of the skis.
The rigged skis weighed 33.2 pounds each. 1/8" diameter control cable was used per 43.13 for skis and a plane this size. After finding the center of balance for the rigged skis I made a new W&B. This is easy to do when existing component weights and arms are already in an Excel file.
A pair of Dolly's were fabricated too.
I'm sure there are other ways to accomplish the same results but this is how I rigged these skis.
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