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Spinner attaching screws Button head or Counter sunk

HIIFLY

Well Known Member
I am just about ready to paint the Spinner but before I do I want you opinion on which type of Screw is prefered ??

1. The Button Head / dome

2. The counter sunk with a counter sunk washer

If I use the counter sunk I need to counter sint the holes in the Spinner before I paint it . So which is Prefered ?? Thanks to All who respond and have a Great Thanksgiving . Joe :)
 
Since Van's provides both in their kit (at least they did with mine), you can use either. I like the truss head look so I'm starting with those. If I decide to later use countersunk I can. Can't go the other direction though. You don't need to paint before countersinking. The tinnerman washer will cover the countersink.
 
I used the button head style with a nylon washer under it. I did the same with the wheel pants where they attach to the bracket. Like the previous post says, I can always go to c'sunk later. I was initially worried about thining the fiberglass, but I think it would work fine either way. Now that I'm flying it will probably stay the way it is for some time :)
 
Flat head & Dimpled Washer

Flat head & Dimpled Washer. No avoidable bumps anywhere on the exterior.

Bob Axsom
 
I did both

I used flush screws on the front plate (running a hartzell c/s prop) and I did button head screws on the back plate - not sure why, but I like it and no issues thus far.

Not a great pic, but you can just see the flush screws mid-spinner and the buttons along the back.
FP20072011A0001W.jpg
 
Drag.

Van has a really clean airplane with flush everything, so we "flushed everything":)

BTW Brent, can you tell if the half 'n half spinner paint deters birds?

Best,
 
It's my understanding that when using a countersunk washer (looks like a dimpled washer with a flat section and a conical section) on fiberglass, that you don't want to countersink the fiberglass anyway. You want a straight hole large enough that the washer sits with just the flat section on the fiberglass.

If you countersink, the washer will be forever pushing on the sides of the hole, and will eventually lead to stretching the hole, and possibly cracking. With the larger straight hole, the washer only compresses the fiberglass to hold it in place.
 
If you countersink, the washer will be forever pushing on the sides of the hole, and will eventually lead to stretching the hole, and possibly cracking. With the larger straight hole, the washer only compresses the fiberglass to hold it in place.

Exactly... you will find in a very short period of flight time wallered out holes in the spinner and the tinnerman will eventually work its way thru the spinner.
 
I am not sure much deters birds. Once many years ago in the Navy it was decided that if your landing light was left on it would deter bird strikes in the pattern. Two days later one of our aircraft with the landing light on took a bird strike dead center on the light. Knocked the light off and a gear door and fodded both engines. The ready room peanut gallery decided the light gave the birds a target!!

George
 
Reiley on this rare ocassion I disagree

Exactly... you will find in a very short period of flight time wallered out holes in the spinner and the tinnerman will eventually work its way thru the spinner.

I thought I would just leave it in the title but not only have I not had any problem in more than 600 hours in some pretty hard use but if anything the uncushioned side load of a bare screw with imperfect tightening will create more damage with spinner impact.

Bob Axsom
 
I used countersunk washers glassed in to the spinner on the RV-8....1400 hours and 6 years, and no issues.

We have pan-heads on the RV-6 and the new RV-3 (only around the base - no forward bulkhead on the Whirlwind spinner).
 
Hidden screw MT spinner

I sure like the looks of the "screwless" spinner on the Super 8. Has anybody gone this route with the composite MT spinner? I'm just about ready to hang a MT three blade on my RV-8.
 
I'm with Paul. If you want tinnermans countersink the glass and epoxy 'em into the hole, flush and fully supported, before high-build primer and paint.

Most tinnerman installs hang out in the breeze so badly that they are unlikely to be less drag than a truss head screw.

I sure like the looks of the "screwless" spinner on the Super 8.

I did too....Kahuna, my hero ;)

2q83676.jpg
 
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Determining factor

The thickness of the glass layer must be equal or greater than the height of the "dimple in the tinnerman washer. Otherwise the washer bottoms on the spinner bulhead without any clamping force on the fiberglass. Instant wallowing and bad stuff results. I disagree about the large holes. I think a countersink is better. If fitted correctly, I think there should be better bearing with the tinnermans because of larger area contact. The drag difference has to be minimal. The screws are moving at right angles to the line of flight. Aesthetics? Six 'O' one half dozen etc. For looks, nothing beats the screwless setup if you want to burn up 50 hours work to get there.
 
I thought I would just leave it in the title but not only have I not had any problem in more than 600 hours in some pretty hard use but if anything the uncushioned side load of a bare screw with imperfect tightening will create more damage with spinner impact.

Bob Axsom

That's OK Bob... :) I've seen it too many times, most tinnerman washers on spinners are not installed correctly (sitting high in the Counter Sink) and screwed into loose nutplates. If the screw is not locked down tight the washer chatters and eats a big hole thru the spinner. Our good friend Mike has this issue now, the tinnerman ate right thru the spinner. Fitted properly and epoxy set washers is the best. :) Actually, the tinnerman washers that come from Van's with the kit that (fit the called out screws) are too thick and counter sunk make the washer proud on the spinner. You can drill up the next size smaller washer and re-dimple them and it works very well and you can probably get way with counter sinking and epoxy. The other option would be to build up inside the spinner with some glass so that you have enough material to counter sink for the bigger washer.
 
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I sure like the looks of the hidden screws on that Super 8 spinner. I'm just getting ready to fit up my MT three blade prop and spinner on QB RV-8. Any done hidden screws on the MT spinner?
 
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