another cracked spinner

[Don Nieser]

Robert, sorry I was out of town when you first contacted me. I was investigating a cracked wing spar. I will post information after we have done the engineering analysis.

I have a number of front and rear prop spinners and spinner bulkheads in stock and will try to beat any other prices.

Instalation of the spinner is critical: We use 2 people, have one person push (at the tip) of the spinner onto the spinner bulkhead, ( you can use up to 4 spacers (1457305-2) inside the plastic support (p/n 1457302-3)). Use enough spacers so that when you push on the spinner you can just get the screws started. It may take a couple of trials to get the proper number of spacers in place. Keep the pressure on the tip of the spinner as the second person start all the screws, then go around the spinner and tighten the screws in an alternating pattern. Also, I wonder some times if the plastic spinner supports have some wear, distortion or that 4 spacers are not enough. It may be that new spinner supports should be used.
Don Nieser
Commodore Aerospace Corp
405-503-4686
nieser.02.337parts@juno.com

[hharney]

Don

I have seen a spinner that has been grooved inside from improper fit. With this issue what do you suggest?

[SkyMac]

Both front and rear spinners on mine had deep internal grooves at the location of the nylon spinner support, when we striped them back to commence polishing we found the groove had almost worn through.

Now I have two polished ornaments, I had managed to obtain two rear spinners sets and a front spinner set. Now polished and fitted, I will be interested to read comments on the cause of the grooves, my thought- not enough washers.

I have a spare rear set just in case, an extra rear backing plate as well and front backing plate. Recently I have been offered another another front and rear set, yet to inspect them.

Dave

[hharney]

I would suspect fitting issues cause the internal abnormal wear. There may be some justification to prop balancing also but the higher percentage of damage is most likely the spinner not properly fitted. More washers would be one concern but I thought I read somewhere that the number of washers is limited. This would indicate that the spinner or the internal support is worn beyond specs. I have seen many units with multiple washers, homemade too. One needs to be careful as the internal support will be compromised on the prop hub if too many washers are stacked up. Remember these things are 50+ years old and have been removed at least 50+ times.