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Anyone recognize these tailcone fasteners?

subpar_bucker

Well Known Member
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?
 

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Did they also use them on the fiberglass faring on the front of the vertical fin? Wheel pants would be another place.
 
I use them on my airplane for all flathead screws...
-
 

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Tinerman washers as mentioned above can be purchased through Aircraft Spruce. I keep a stock of these in my parts box, size 6, 8, and a few 10. Always good to keep some in stock.
 
My plane is built / painted using the panhead with nylon washers, can it be converted? Will it require repainting each screw area?

Can it be converted?
YES

Will it require repainting each screw area?
NO

You will have to countersink the screw holes. A few turns with a handheld deburring tool is all it takes.
 
Can it be converted?
YES

Will it require repainting each screw area?
NO

You will have to countersink the screw holes. A few turns with a handheld deburring tool is all it takes.

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

screw washer.jpg
 
The “Flush” washers are what you want.

https://www.aircraftspruce.com/catalog/hapages/finishingwashers.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.
 
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.
 
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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-washer-nickel-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.
 

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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”.
 

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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
 
I believe I accurately answered the original post question “does anyone recognize these fasteners”. I have been amassing spare parts for my soon to be one year old aircraft and I was curious why there was no mention/depiction in the KAI of the flush washers used with the 2) AN507C832R8 machine screws attaching the upper cowl hinge pin cover panel (F-1240B) as well as additional locations using the AN507 screws (upper firewall, forward stab skin (VS-1204)).

The flush washers are only used with the AN507C832R8 screws which in turn are used with countersunk ALCLAD sheet. The fiberglass cowl is not countersunk. The cowl is attached with AN525 screws using nylon washers.

I do not think the flush washers provide any structural benefit. I believe Van’s utilizes them on their SLSA builds solely to mitigate paint damage.
 

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

View attachment 39519

Easy to make. Thin SS washers from McMaster Carr, dimple each washer, Done. I use these for a cleaner look on some fiberglass. 700 flying hours, and no hole enlargement. Keeps the paint from chipping some, and yes, I keep a stock of Tinnerman washers for use where needed. Simple to convert fiberglass holes to accept Tinnerman at a later date if needed.
 
Nylon Tinnerman Washers

I went with these after my painter did not replace my Tinnerman washers on my wheel pants. Was told once you use Tinnerman it will damage (scratch) the paint (Under the Tinnerman washer) which is ok as the washer should hide any scratching it produces but you need to leave it on. Like the Tinnerman washers these help spread the load. 100 deg countersunk screws seem to fit well. So far, no paint scratching. I preferred to try and stay away from the Tinnerman and insured extra fiberglass was used to give the area more support, but the front wheel pant gets a lot of vibration. After about 50 hrs. they are holding up well and have not scratched the paint. They also come in many colors.

https://www.ebay.com/itm/284961012984?var=586760915160
 

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