[jerry98b]

RV-9A

The R2 plans call for three (U-408) spaces to be made from 3/8 x .058 6061-T6 tubing for each wheel.
The R3 plans call for three (U-00408) spaces to be made from 3/8 x .058 4130 steel tubing for each wheel.

I was sent R3 plans, but not sent the steel tubing; I was sent the aluminum tubing. Do I need to just follow revision 2 plans or contact Van's to get the steel tubing for revision 3?

 

[Desert Rat]

I believe the issue is that the pants take a beating and over time, the aluminum spacers can compress, resulting in the attach bracket getting loose. A common fix here is to to replace the aluminum spacers with steel. That's been going on in the field for a long time.

When was rev 3 issued? It has to be pretty recent since there are jillions of Rv's flying with aluminum spacers.

Bottom line; you can use aluminum, and if they get loose at some non-specific future time, you can replace them with steel, or you can just get some steel tube and do it now.

I put mine all together a couple of years ago and I'm reasonably confident that it called out aluminum tubes at that time, but I had it in the back of my mind to replace that with steel if the pants ever show signs of getting wobbly. Glad to see that Van's updated their print.

 

[jerry98b]

Opened a ticket with Van's and I was suppose to have been sent a steel tube instead of the aluminum one. They are sending me the correct part for me to make these spacers.

 

[planenutz]

Rather than manufacturing your own spacers from steel you can buy stock spacers which will work.

I don't have a lathe to cut the faces accurately and I didn't want to spend time with a hacksaw and a file to get the spacers perfect, so instead I purchased NAS spacers ready made. You can get them in a "T-section" profile as well - look up part number NAS77.

With the NAS77 bushing or spacer it increases the surface area of one of the bearing surfaces. I would put this larger bearing surface against the aluminium plate (U-810) if you go ahead and use the aluminium version. I've had to repair these plates for cracking on other aircraft in the past so now I manufacture them from 8130 steel and save myself the trouble of manufacturing new ones later.

 

[jrs14855]

Replace the aluminum plate with the aftermarket stainless plates. The spacers can be cut with a hacksaw and finished with a file on top of a block of wood in a drill press. Chuck the bushing in the drill press. If you have a disc sander the tube can be finished on both ends, cut off two bushings and repeat.