#4 washers

[mark cheney]

still looking for #4 ss countersunk washers -- spruce, wicks, ecas, genuine all only go as small as #6. I have seen them on an rv 6 or 7 wingtips but cant remember where

[RV_7A]

Mark if you saw them on the wingtips of an RV they were most likely the #6 countersunk finishing washers with a small overall diameter. I purchased these from Wicks for the very same reason. I liked the look of the smaller washer, it looks very clean.



http://www.wicksaircraft.com/catalog...572/index.html

-Jeff

[mark cheney]

thanks jeff- i just ordered them .
mark

[szicree]

Do we need washers on the wingtips??

[RV6_flyer]

Originally Posted by mark cheney

still looking for #4 ss countersunk washers -- spruce, wicks, ecas, genuine all only go as small as #6. I have seen them on an rv 6 or 7 wingtips but cant remember where

Mark:

I used #4 SS 82 degree NAS391B4P Finishing Washers from Aircraft Spruce.
http://www.aircraftspruce.com/catalo...ingwashers.php

I used my #4 dimple die to change these to 100 degree to match my screws.

The only reason to use this on the metal where they attched the fiberglass wing tip to the airplane is to minimize the Paint cracks and chips that occur without them.

If I had it to do over again, I would use more #4 screws in the non structural areas of the airplane.

[mark cheney]

Steve, I have 150 hours and a good bit of acro on my rv and see no signs of problems with the wing tips. I used clevelands kit. The quest for washers is all for looks as far as i am concerned
Mark

[f1rocket]

Originally Posted by mark cheney

The quest for washers is all for looks as far as i am concerned
Mark

Well, not really. If you have a fiberglass part where the attach screw goes through the fiberglass first, AND that part is subject to a lot of vibration, you might want to consider them.

For wingtips, I don't think they are necessary. However, for wheel pants, I'd recommend them. I just finished adding them to my wheelpants after a couple of the screw heads pulled through the glass. That's AFTER I reinforced the holes with 4 plys of BID. (Now, you could make the argument that its because of my bad landings, and I probably wouldn't argue with you!)

In line with the thread topic, I just made a couple of #4 washers for my wheelpants last night. I took some .020 aluminum and polished up a corner. I then drilled and dimpled the screw hole. Using the dimple die as a guide, I marked the diameter and trimmed the washer out. A little dressing of the edges and it looks good. This is more than strong enough to keep the head from being pulled through the glass.