Anyone recognize these tailcone fasteners?

[RVbySDI]

Originally Posted by Ralph Inkster

Clarification of above process - this applies to fiberglass fairing’s & components only.
If you have a metal to metal cover that you wish to convert, much bigger process involving dimpling, changing nut plates, & probably some painting

Yes, metal may require dimpling. However, there are some situations when a metal piece can be countersunk too. It depends on the thickness of the metal and the diameter of the Tinnerman washer. As for the question asked by the original poster, I replied with the notion he was asking about fiberglass.

[seagull]

Just finished converting all my pan head screws to flathead with Tinnermans.

[seagull]

I saw these in Tony S post. Does anyone recognize the washers used? They are smaller OD than Tinnerman's.

[Bob Y]

The “Flush” washers are what you want.

https://www.wicksaircraft.com/shop/6...chTerm=Washers

I’m planning on replacing my “Tinnerman” washers with these during my next CI. I test fit one a friend had and I found the #8 washer to be too large. The #6 is tight, but gives a better fit in my opinion. I’m going to go with the #6s.

[seagull]

Originally Posted by Bob Y

The “Flush” washers are what you want.

https://www.aircraftspruce.com/catal...ingwashers.php

I’m planning on replacing my “Tinnerman” washers with these during my next CI. I test fit one a friend had and I found the #8 washer to be too large. The #6 is tight, but gives a better fit in my opinion. I’m going to go with the #6s.

I just replaced all mine, tail cone top and bottom #6, wheel pants #6 & #8, cowl top and bottom #8, and spinner #8. I used all Timmerman washers 100 degree. The flush washers you linked to are 82 degrees, I suppose you can change screws but typical is 100 degrees.

[Bob Y]

Sorry, thanks for keeping me honest. I replaced the link. Beware if you order the #8 washers from these guys. Note the hole sizes of the #8 vs. #10 washers. They have them backwards. I blindly ordered their posted #8s and discovered they were too big. I notified them and got a response something like “yea, we know it’s screwed up but we’re not going to give you a refund or return or change the listing”!!! Great customer service.

[DIVANS]

[/IMG]

Originally Posted by subpar_bucker

Another detail I noticed on the Van's built 12iS I saw last week was the fasteners holding the top portion of the tailcone fairings. The screws that pass through the fiberglass into the nutplates underneath appear to have a washer under them. It seems like this might help to protect the fiberglass over time - and also help protect the paint.

Anyone know what's being used here?

I called Van's today and I was told these "flush washers" are not available through Van's and they are only used by the factory when assembling their SLSA RV-12iS's. They are used with my aircraft's AN507C832R8 machine screws.

The Van's employee took the attached photo and sent it to me a few hours after we spoke.

I ordered a box (#100) and should receive it next week.

https://www.auveco.com/no-6-flush-wa...l-on-brass-602

https://onlinecatalog.auveco.com/Auveco-Catalog/180/

To be clear, Van's uses the #6 size washer (UPC Code: 821641523563) with the #8 size screws (AN507C832R8). I took one of the washers off my plane and measured it to verify the sizing.

[Tommy123]

you sure those ebay washers have the correct angle?

[DIVANS]

The Van’s employee I spoke with told me he would visit the SLSA assembly floor and take a picture of the washer box and send it to me. The photo I posted is the photo he sent me.

I measured the dimensions of the washer I removed from my aircraft and the measurements match. The washer I removed is very thin and flexible. I believe it would readily “mold” to the taper of the AN507.

The KAI does not reference these flush washers. I was told the flush washers were technically “not necessary”. The Van’s employee stated he believed they were used on the SLSA planes to help “protect the paint”.

[scsmith]

Just a note:

The Tinnerman washers are good to use on fiberglass because they spread the fastener load out over some of the flat area, reducing the stress and wear on the countersunk portion of the hole.


The "flush" washers depicted here won't do that. They don't increase the bearing area appreciably over the original size of the screw head.

YMMV