Aileron conversion kit & rivet info – 9/27/15

We started installing the aileron control conversion kit today.  It uses different bearings and a push/pull tube vs. cables and it moves smoother with less force.

aileron control upgrade

 

We’re missing the needle bearings for the post and asked PA to send.

 

rudder pulley

rudder cable pulley

drilled solid rudder tubes

It was difficult to drill holes through the rudder pedal, is solid aluminum.  Manual says it is a hollow tube and that you should
use short SBL-44 rivets on each side of the hollow tube but that won’t work.  Instead we ordered long rivets with at least a 0.75 inch grip length
that go all the way through the tube.

General Rivet Info:

Alcoa Fastening Systems is the one of the big rivet manufacturers and they seem to have defined the rivet naming conventions.
Marson is the brand name for their rivets so you’ll sometimes see a rivet name like ABL4-4A referred to as a Marson #.

Decoding the Rivet Name:

The first letter is the rivet material – A=Aluminum, S=Steel, C=Copper, SS=Stainless Steel
The second letter is the head type – B=Buttonhead, C=Countersunk
The third letter is optional, it will either be L=Large Head 0.375 inches or Blank for regular head 0.25 inches
The first number is the rivet body diameter in 32nds of an inch
The second number is the maximum grip length of the rivet in 16ths of an inch
The final letter is the rivet Mandrel material – A-Aluminum – S=Stainless Stell, B=Brass, etc.

Screen Shot 2016-04-17 at 9.50.59 PM

Examples:
ABL4-4A is Aluminum rivet, Buttonhead, Large Flange, 4/32 body diameter, 4/16 grip length, Aluminum Mandrel

I’ve been using a lot of the plated steel SBL4-4 rivets in the wing. They make a similar stainless steel rivet but I don’t see
a large flange type.That means that the flange is only 0.250″ vs. 0.375″.
As an example you can buy an SSB4-4S rivet. However I would want an SSB4L-4S rivet with a larger flange which doesn’t seem to exist.  The stainless steel rivets have a better shear and tensile strength but I don’t think it is a good idea to change to a smaller flange size.

 

Another thing that is tricky with rivets is that just saying “steel” or aluminum” or “stainless steel” isn’t enough. If you do a search for “IFI 114 Break Mandrel” you’ll find that aluminum rivet bodies can be made of 1100, 5050, 5052, 5056, or 5154-series alloys, with strength varying by a factor of 2-4 from the worst to the best. So it’s not enough just to substitute one vendor’s “aluminum/steel” rivet for another – you have to look at the full spec sheet, including shear and tensile strength.

Rivets for the rudder pedals:
For the rudder pedals we ended up purchasing some 3/16 stainless steel rivets from McMaster Carr that had a .751 to .875 grip length.  http://www.mcmaster.com/#97525A522

Screen Shot 2016-04-28 at 7.43.52 AM

We needed a grip length of at least 0.75 to go through the pedal cover and the solid aluminum tube.

Future learning – we should have not riveted the rudder pedals but instead drilled them through and attached them with bolts and nuts.
This is because it is desirable to be able to remove them.  We had to drill out the rivets and wished that they had been bolted.

 

Notes from today:

sept 27 2015 notes