Thorp Air Command - T18.net

For what it's worth, one of the most common reasons for spinner cracking is a spinner that doesn't run true. The forces on a wobbly spinner can be tremendous. Also, when fitting a front bulkhead without screws, make sure you have a nice tight fit - build the circumference of the bulkhead flange up with urethane tape or something similar if necessary. Polish all edges of course. I have 1300 hours also on my Ken Brock spinner with no cracks (knock on wood). By the way Rich, ACS Products is Aircraft Spruce... their manufacturing operation. That is my understanding anyway, as I dealt with them when I was making & selling cabin heat boxes through Spruce.

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John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

Yep...wobble is not my game . I went to great lengths to insure there was none. I followed Tony B's instructions and the spinner is a tight fit ! I used 1/32nd" rubber chaff strip attached to the front bulkhead with 3M SUPER weather strip adhesive to attach it . That little bit of rubber provided a very snug fit . W/O it the spinner would have a bit of slop in it . Now that I have time to reflect and consult with the higher aluminum powers I may have found a possible cause ? When the aft bulkhead screws in the area of the cut out (crack area) were tightened down I noticed a slight flex of the spinner material when they were tightened down . No other area on the spinner, just the cut out area ? I also noticed this on the work bench when I pressed in on the first screw hole attach point (in the cut out area) for the aft bulkhead . There was a noticeable flex in the material that went to the crack area ? Stress ? I tighten down all the spinner screws with a 7 volt drill driver that has a clutch to a low setting to snugs them up like lug nuts on a tire . Then I go back around on a slightly higher setting . As a final check I use a screwdriver to verify the snug "setting." The screw driver always wins !

ACS Products Co. Precision Machining , Lake Havasu-AZ. They do supply to Spruce , Wicks and a few others . YOU ARE CORRECT SIR !

RB

I'm hoping to find a big crack in my left sear next year, Rich. If you know what I mean.

I don't think the crack is a result of the flex you describe, RB. All spinner will relax in the area of the cutout due to the cutout. The lack of material will allow the metal to flex outboard. Your screws are just putting it back. Not to worry.
Cubes

I have a friend who built a T-18 here in Colorado. I believe that he broke 3 different propellers, and consequentially his airplane seemed to be flying without a spinner more than with one. It took him awhile to get the hang of the effectiveness of his brakes, I guess.

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John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

I think you are probably right Cubes . I tend to analyze an engineering problem way too deep with my Liberal Arts Degree !

RB

Dick : You will need someone else besides me to stop drill that crack !

RB

John: Is this the outfit ? (ACS) They make an assortment of aviation products including the BN-1 spinner .

RB

Yep... note that the president of the company is John Irwin. Does that last name ring a bell?

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John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

Yep I have talk with John Irwin once or twice on the phone at Corona . I did not notice his name at the Lake Havasu facility ?

RB

Scott: I ordered a new BN-3 Spinner from Spruce . I do appreciate your offer !

RB

Dan : I will bring the spinner to KVIS for you to look at . Worst case we can have a show and tell on spinner cracks ! I ordered a new BN-3 from Spruce East and is should be here Sat. Gives me a few days to cut and drill and then send to the polish shop . I hope I can still get the same $40.00 high luster polish job ? I hope he is still in business ?

RB

Okie doke Rich, sounds good..........Dan

RB, let me know if your $40 spinner polish guy is still in business ... have some business for him!

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Lee Walton
Houston, TX
N51863,N118LW
KEFD

OK Lee : How many do you have so I can let him know , if he is still in business ? At the time when I set up the spinner polish for the group it was $40.00 (What a deal !) and you paid postage both ways . Let me sniff it out as I can hopefully have my new spinner ready for him early next week ? Don't hold your breath on the $40.00 deal as I am sure it has gone up . When I checked with Spruce they take about 4 weeks to polish the beast and charge about $85.00 . If anyone else has a spinner that needs polishing or polishing to remove the tooling marks let me know as the more we have for him the better ! I should be able to get down to his shop in the next few days .

RB