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BushCaddy 164 Wing Failure Update
By James Eby, EAA 786852
April 2021 – We featured an article by Alex Tarussov regarding this spar failure in the December 2019 edition of Bits and Pieces, "Wing Spar Failure on a BushCaddy L-164" — Ed.
Following the in-flight right wing failure of my BushCaddy in May of 2019, I had expected the repairs to be completed by the end of that summer. That was wishful thinking. The repairs are now expected to be completed this May 2021.
The problem of finding a company to bend the C-form BushCaddy spars seemed almost insurmountable. It was no problem finding companies with press breaks, but the dies were for steel, and I could not locate a company with dies of the larger radius needed for the aluminum. I checked with EAA in Oshkosh and numerous companies across Canada and the United States, to no avail.
I had decided to use 2024T3 instead of 6061T6 and thicker material. Several attempts resulted in cracking or at least visual grain alteration. BushCaddy apparently had its own dies, and best guess was that the dies were with the Chinese company that bought BushCaddy. I did manage to locate the company, but they said they did not have the dies and were only building the smaller BushCaddy airplanes. They were helpful and did provide me with the original spar drawings.
In the end, after more than a year of searching, I managed to find the place. A friend had major work done on a seaplane at Lac-à-la-Tortue and suggested I call them. They referred me to a company called Acier Rayco in Saint-Tite, Quebec, an hour and a half from where I live. They simply said no problem, and after finalizing the drawings, produced results that were better than expected and better than original.
New BushCaddy Rayco front spar.
The right wing assembly began last fall and has been completed; we are presently modifying the undamaged left wing.
BushCaddy front spar installation progressing.
The rear spars were increased in thickness from 0.050 inch to 0.063 inch, using 2024T3 instead of original 6061T6. The four lightening holes in the high-stress area (failure occurred through one) were removed. Two backing plates have been added on the inboard side of the spar in the high-stress area. Rivets used for spar attachments changed to 5/32 inch from the original 1/8 inch.
The front spar design was changed due to the difficulty of bending the 2024T3 aluminum. BushCaddy had upgraded the front spar of 6061T6 to 0.080 inch at some point, but bending 2024T3 was difficult. The front spar is 0.063 inch and angles; 75x75mm of 0.040-inch 2024T3 has reinforced the flanges. Two backing plates of 0.040-inch 2024T3 have been fitted in the high-stress strut attachment area.
BushCaddy front spar backing plate.
I have been in discussion with another 164 owner in Winnipeg on the spar upgrades. He has located a company to assess the original wing design and upgrades. It's not cheap, but we will share the cost and it'll be well worth it in the long run.
Back in the air this spring!