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-   -   Annuals, broken parts, and assistance request (https://vansairforce.net/community/showthread.php?t=179242)

airguy 02-03-2020 10:42 AM

Annuals, broken parts, and assistance request
 
I'm currently in the process of conducting my annual inspection and installing the SDS EM5 engine management hardware, and associated with that I needed to pull the flywheel to drill and tap it for trigger magnets. To pull the flywheel I need to loosen the alternator belt first, and as soon as I took a look at the alternator, before I even loosened the first bolt I knew something wasn't right. The belt angle was wrong and the alternator was obviously not hanging correctly, and as soon as I started to loosen the first bolt the problem was obvious.



And the bolt that was holding it also caught some wear, it was obviously working for some time. 560 hours since new, 193 hours since last annual, and I know I had the alternator off for that annual.



This is the short bracket and bolt that holds the Plane Power 60-amp alternator to the Skytech starter, I'll obviously need to order new examples of each, and thus the question here. Can anyone tell me the appropriate part numbers for these? I put in a question on the Plane Power website but do not have a response yet.

Sidenote - this is why we do GOOD annuals, and not just a paper exercise! If you don't put a wrench on the part before putting a checkmark on the paper, you didn't do anything worth doing.

Walt 02-03-2020 11:10 AM

Do yourself a favor and get a B&C now.

Ralph Inkster 02-03-2020 11:13 AM

I just googled 'plane power installation sheet' and came up to a page listing all the pdf sheets. There are part#s on them.
& B&C is another option...

airguy 02-03-2020 11:28 AM

Quote:

Originally Posted by Walt (Post 1405195)
Do yourself a favor and get a B&C now.

I recognize that there is a level of heartburn that exists with several folks with Plane Power - but this is a bracket problem, not an alternator problem. Are you saying PP makes low-quality mounting hardware?

Ralph Inkster 02-03-2020 12:44 PM

Looking at the picture,I?d think the bolt wasn?t tight. Was there a tube spacer between the case bracket forks?

airguy 02-03-2020 01:40 PM

It took a bit of Google-Fu and about 30 minutes online with a parts distributor but I got the part properly identified and ordered - only $12 plus shipping, a rarity in the aviation parts world that truly surprised me.

Quote:

Originally Posted by Ralph Inkster (Post 1405218)
Looking at the picture,I’d think the bolt wasn’t tight. Was there a tube spacer between the case bracket forks?

No, this bolts directly to the right hand side of the alternator when viewed from the front of the airplane, and extends from there to the left hand side of the starter, the "A" mounting tab on the Skytech 149NL series. There are no spacers other than a few washers. The broken piece is the starter end of the bracket.

Boyd Birchler 02-03-2020 06:59 PM

I've seen this type of wear caused by the bolt not being tight enough. The reason it was not tight enough was the use of a drilled bolt with a castellated nut. Torquing properly is a chore because often you could not get to the next castellation point without being too tight and one back ended up too loose. My solution is use a non drilled bolt and a high temperature self locking nut.

Ralph Inkster 02-03-2020 07:50 PM

Check carefully when installing the new bracket that it sits flat at each end, & if some washers might be needed to make it sit flat. Not sitting flat would cause bolts to not torque properly and create spot stress points that could break off the end.

I'd also suggest installing a new belt during reassembly.

airguy 02-04-2020 07:14 AM

Quote:

Originally Posted by Ralph Inkster (Post 1405325)

I'd also suggest installing a new belt during reassembly.

Absolutely. As much trouble as it is to pull the prop and flywheel, there's no way I am going to put the old belt back on there, they are too cheap.

bjdecker 02-04-2020 07:57 AM

Part #'s
 
Bolt -- AN7-42A
Bracket -- 10-1002

and for future reference, you need 450 - 500 inch lbs. of torque on that bolt...


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