F

Fedico94

Active Member
I am following the MilSpec Vans RV instruction sheet. I decided to use the minimal thicknes recommended by MilSpec of 0.040 inch for the receptacle mounting lip. This allowed it to bend/flex more easily to the contour of the fuselage edge. (2024T3)

Now I have countersunk the receptacle mounting lip and note that it meets the permissible countersinking practice per AC65-15A (the text also says while it is permissible but should be avoided). This is to say that the countersunk head reaches completely through the mounting lip. This mounting lip will be backed by the stainless steel of the camloc receptacle which is riveted with AN426AD4-4.

I read where some on this site would not countersink for an AN426AD4 rivet unless the material was 0.050 or greater. Question. Would it be advisable to use the Mil Spec receptacle plate as the back-up plate for this installatin, or should I rivet another plate of aluminum to the present 0.040 receptacle mounting lip then mount the receptacles to this doubled up mounting lip ?
 
Fedico94 said:
I am following the MilSpec Vans RV instruction sheet. I decided to use the minimal thicknes recommended by MilSpec of 0.040 inch for the receptacle mounting lip. This allowed it to bend/flex more easily to the contour of the fuselage edge. (2024T3)

Now I have countersunk the receptacle mounting lip and note that it meets the permissible countersinking practice per AC65-15A (the text also says while it is permissible but should be avoided). This is to say that the countersunk head reaches completely through the mounting lip. This mounting lip will be backed by the stainless steel of the camloc receptacle which is riveted with AN426AD4-4.

I read where some on this site would not countersink for an AN426AD4 rivet unless the material was 0.050 or greater. Question. Would it be advisable to use the Mil Spec receptacle plate as the back-up plate for this installatin, or should I rivet another plate of aluminum to the present 0.040 receptacle mounting lip then mount the receptacles to this doubled up mounting lip ?
Click to expand...
Actually, .032 is considered the minimum thickness to accept a standard 100? machine countersink to accept an AN426AD3 rivet. HOWEVER, if the countersink produced the slightest bit too deep, an undesirable knife edge is inevitable. For that reason, some but not all designers do call out for .040 material to be the minimum thickness for AN426AD3 machine countersinking.

That can be a moot point because even though AN426AD3 rivets are perfectly acceptable for use in .040 thick material, pros commonly use NAS1097AD3 rivets to install nutplates etc. regardless of how thick the material is.

If your instructions or the camloc receptacles themselves do require 1/8" rivets for attachment, I'm sure the use of NAS1097AD4 rivets in your situation will be perfectly acceptable with no risk of generating a knife edge.

2hwcsoy.jpg
 
Great Tip!

Rick has posted this tip a few times before, and it is a good one! He is a pro, after all !! :D

NAS 1097AD3 rivets are a little hard to find, though - Spruce does not carry them, and Vans does not list them in their catalog, or on "The List". However, if you ask for these at Vans, they DO have them and will sell them. I just received some last week.
 
Cowed Cowl

Great advice for the remaining rivets for attaching the camloc receptacles.
BUT what advice,if any, to address my concern for the AN426AD4-4 drilled holes that I have in place for the entire lower cowl ?
I could shoot myself for not thinking of the OPPs rivets, they are sitting on my work bench buried beneath the AN426's. NOAH thanks; I must take you guys out to dinner before I retire or have you come over and advise me on completing the firewall forward. You should write a book NOAH.
 
063

I used .063 on the install of the Sky Bolts on my 7. When scalloped it handled the minimum contour fine and counter sinking was easy. 040 is right on the edge and creates the issue you are encountering.

I'll use .063 on the new 7 as well.
 
more 2cents

I just followed the instructions and used the called for materials for my skybolt camloc installation. I used .05 strips and AN4 rivets. It did not feel near the edge of any acceptable limit. Only 120 hours on the plane so far, and it's solid. The cowling has been on/off a fair amount, as would be expected in the first 100 hours.

Here's what I ordered from ACS:

1.00 of 03-28250 2024T3 ALUM SHEET .050 2'X4'
 
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