Mixture Arm Interfere with Cowling
 

Guys,

I finally have gotten moving on my air box. As I got into it I realized my throttle body mixer had a straight arm that would have required removing way to much of the top plate. I replaced it with a bent arm and now have interference at the very forward throw of the mixture arm with the cowling. Any one else experience this.

Mike
40644

A few of us have this. I wound up building a small cavity in the cowl and glassed it over on the outside of the cowl. A very minor bump out. The other option is to redo the air box and move it more offset in the opposite direction.

Another possible option is adjust the clocking of the arm.

The serrated interface at the base of the arm provides for a lot of different clocking positions.

The ideal position is one that will have the arm 90 degrees or perpendicular to the push/pull member that is actuating it, but this can be compromised somewhat as needed as long as you assure that the arm can not get close to going over center at either extreme end of travel.

Tried Clocking . . . Possibly need cowl bump
 

Guys,

Thanks for the input I messed around this morning prior to work with the clocking - one of those keep me up at night issues - and couldn't find a position that wouldn't interfere with the cowl though it did help.

I tried moving the turn buckle to the inside of the arm and it just will not get by the box and on the outside it starts rubbing at about the vertical position (6'oclock) and forward.

I would love a photo of the cowling bump if you wouldn't mind sharing.

Thanks

BTW- I don't know if it is just my desire to be done but I have been finding the Air Box a major time suck and pain. Van's should consider putting together some decent instructions. (Just venting, I feel better already:-)

The prototype RV-10 has a bent arm with the control cable connected at the inboard most hole, and the additional length of the arm trimmed off.

I too would like to see a picture of the bump/recess that you had to make. Since installing my cables last week I haven't yet reinstalled the cowl and really don't want any surprises.

Thanks

arm
 

Scott,

Arm only has one hole but I could drill a new one up closer to the focal point? That would solve a lot of my problems. Thinking ...

There is some info on the bump and a picture here: https://myrv10factory.wordpress.com/...rglass-finese/. Basically we added some foam outside of the cowl where we needed the bump. Glassed it over and smoothed into the cowl as much as possible. Then from the inside we cut out the original glass and ground away the foam we had applied to the exterior of the cowl.

Hmmmm.... The one on N410RV has obviously been trimmed (I took a quick look yesterday while the cowl was off) but maybe it was shortened just enough to remove the original hole and then a new hole drilled (too long ago for me to remember).
The bottom line is it clears fine with no bump added to the cowl and there still seems to be more than enough fine-ness to the adjustment.

A lot depends on exactly where your cowl sits. The MT prop spinner has a flange on the back which means that the cowl has to be trimmed back more than usual. It caused me a couple of issues - one being running out of flange at the rear of the cowl and the second interference with the mixture control.

I too have just fitted a "bump". I cut a hole, lined with 3 layers of mat and then filled from the outside. Still have to do final rubbing down, smoothing and painting but it solved the problem.