Question on Flap Motor Installation

On the 6, the flap motor runs to it's fully extended stop, then we adjust the flaps retracted position to match via the turnbuckle/linkage rod. On the 10, the flap position is set when it hits the rear spar. My question is, do I try to precisely adjust the flap against the spar after the motor reaches it's max extended position or do I leave the travel a bit longer and let the motor start slipping when the flap hits the rear spar and can travel no further? I am just not sure how much force this puts on the flap and it's linkage before the motor slips and obviously concerned about that approach.

I have the FPS system, but prefer to set up the motor linkage correctly, in case that unit misbehaves some day.

Thanks for any input.

Larry

I ran the motor to the stop, then adjusted the linkage to set the flap to the fuse.

Mike, does your method take all mechanical slop out of the linkage?

If not, then I can see the merit of Larry's idea, leaving in a TINY bit of pre-load in full-up.

OTOH, aerodynamic forces would dictate that even if there is play in the linkage, if the flaps CAN reach full-up against the spar when the servo is in the up position, then in flight that is exactly where they WILL be. So, compressive pre-load in the linkage might be unnecessary and possibly a bad idea.

I haven't rigged mine yet, so I'm spit-ballin' from my armchair understanding of how this all works.

Bill Boyd said:

Mike, does your method take all mechanical slop out of the linkage?

Click to expand...

Bill, this is from memory------I rigged the flaps in 2010. Pretty sure I used just a very small bit of "preload" -----maybe a half turn on the rodend after contact with the spar.

There was a lot of trial fitting and filing at the inboard end of the flap to get the correct clearance to the fuse.

Bill Boyd said:

if the flaps CAN reach full-up against the spar when the servo is in the up position, then in flight that is exactly where they WILL be.

Click to expand...

I thought about this and agree with your assumption on a flap installed nuetral to the chord. However, I am suspecting that with a 3* negative reflex the aerodynamic forces will be pushing the flap down and not up and against the spar.

Larry

Scott will likely (hopefully!) weigh in here. I suspect the aerodynamic forces will still push the flaps up into 3 degrees of reflex just fine, but I could be wrong, so...

If the FPS is similar to the VPX I'll tell you what I did.

I made the links per the plans and then pushed the flap up as far as it would possibly go. Did all the clearance sanding and all that as well. With the flap in the full retracted position I connected the linkage.

Then I used the position sensor and VPX configuration to stop the retracted flaps so it's inline with the ailerons at neutral. From there I taped an MD digital leveler to the wing and made 3 position settings each 10 degrees apart.

Seems the flaps could actually go about 33 degrees down, but I stopped them at 30.