IowaRV9Dreamer

IowaRV9Dreamer

Well Known Member
I notice that Vans provided me with 4 of those big thick aluminum washers that are designed to fit under a 1/4" size AN fluid fitting. They are part number "AN Washer, 4D" and came in bag 1966-2.

Where are these supposed to be used? I've been looking on DWG 36A and I can't find them called out anywhere.

In general I think they are used where a bulkhead fitting has to go through thin skin, to provide more thickness and give the nut something to turn against.

The fuel system uses 6D fittings, so that can't be it.

The brake system has 2 fittings on the firewall, where the flex hoses attach to the hard lines. These fittings call out an AN960-716 washer so thaey can't be it. The other fittings in the brake system go through the thick steel gear weldments, and don't call out a washer.

In the vent system there are 2 straight fittings that go through the 0.040 floor skin and 2 more (90 degree) that go through F-902. Could this be where the washers go? Both of these have good detail drawings on the plans and don't show the washers.

Any help would be appreciated.... extra parts make me nervous :eek:
 
I built an 8A, so your results may be different. I had quite a few extra spacers included with my kit. I did however I did use two 4D size for the fuel vent line fittings.

Guy
 
Dave,

I have a few left over as well. I think it depends on your particular installation whether or not you end up using them.

greg
 
I used them on the fuel vent fittings, and had to purchase a couple more from Van's (apparently nobody else makes them - I looked everywhere). Since I'm building 4 tanks, I didn't have enough for my modified vent setup and needed a few more of both the -4 and the -6.

All the bulkhead fuel fittings need these spacers, they are essentially a very thick washer. If you don't use them, or try to use a standard thickness AN washer, the threads will bottom out before the fitting is tight. I can only assume they will be used in the same places for the fuse kit, anywhere a bulkhead fuel fitting is needed.

I apologize in advance for all the proseal smeared everywhere, this was just before cleanup.

1001423fx3.jpg
 
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After looking at the fittings, I think Greg is right. The nut bottoms out on the fitting pretty high up (it depends on the type of fitting). The big thick washer prevents that from happening.

I'm going to use one whenever I have an AN bulkhead fitting going through something 0.040 or thinner. That means one one each of my fuel vents to the outside, and in the inline 90 degree fittings mounted to the bulkhead.

Hmmm.. Vans sent me 4, and now I think I need 4. Scary. (YMMV)

Thanks Greg and all!
 
Rupester said:
So Vlad,where do you use them?
Click to expand...

Terry

2 went to vent line egress DWG 39A view C-C (not called out) and other two to vent line F-902 bulkhead penetration view D-D. I would suggest to put a washer on brake lines fittings penetrating gear leg mount. Not called out but a good practice. If you have extra ones.
 
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On both the RV7A and the RV-10, I used a thick spacer washer between the gear leg weldment and the skin where the AN4 angle bulkhead fitting went through. This keeps the skin laying flat on the belly instead of getting sucked up to the gear leg weldment when you torque the nut. The gear leg weldment is sitting on the flange of the wing spar, so there's a little less than .125 space between the weldment and the skin. YMMV
 
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