SS trim position sensor?

[RandyL]

In order to provide trim position data to the pilot I'd like to use a Ray Allen POS-12 postition sensor to provide trim position on my Super Sport (trimmable HS rather than trim tab on the elevator). Looks like the best way to install it is to mount it with one end on the inboard rib of the horizontal stabilizer and the other end mounted to the bottom rib of the vertcal stabilizer. Anyone done this and have pics of such an install?

[kmul]

randy
i have thought about doing this but ambivalent about doing it or not. the pivot point to achieve 1.2 in travel for the rac sensor is about 5 in forward of the rear stabilizer mount. you could weld a 3/8 tube stub of this length to the right side of the rear stabilizer mount with an offset fishmouth so it is offcenter to clear the an3 bolt as it comes in and out. under the end of the stub weld a tab long enough to have multiple small holes drilled for your final adjustment to get just under 1.2 in travel. below that weld tabs on the fuselage to mount the sensor vertical underneath the stub tab. then just fabricate a rod out of 3/16 tube with 2 tabs on one end for a clevis and a nut on the other to have a tiny similar clevis that screws in and out for another adjustment. probably the 2 clevis should be 90 dergrees from ea other. i had planned on mounting the sensor to a plate that bolted to the tabs instead of having the mounting plate welded on in case i needed to space the unit. you cant attach anything to the rib as it is outside of the fuselage once the cover is in place. anyway this is a thought so far but i think it would work. keith

[RandyL]

you cant attach anything to the rib as it is outside of the fuselage once the cover is in place.

Yikes, hadn't realized that. I'll need to noodle on the bracketry more now. Not being a welder I'm inclined to want to fabricate something out of aluminum.

So you've already figured out the geometry that it needs to be 5" forward of the pivot to get the 1.2" travel, cool! Just curious, do you remember what the total HS travel at the motor rod end is?

[kmul]

travel at the leading edge is about 4 7/16 in. i dont see how you can do it with aluminum without getting even more rube goldberg than my idea was. i did console myself for not doing it by making a rudder lock. keith

[airlina]

Why not keep it simple and use the cable return system that comes in the original plans. I have that system on my Series 5 and it is an easy installation that works fine. Bruce N199CL

[RandyL]

"Cable return"? Not familiar with it, is that some sort of mechanical indicator of trim position?

[hansedj]

We used the trim sensor on our series 6 and it works great. My brother in law and partner came up with these brackets made from aluminum and rc plane parts. pic's on our website under rear fuselage, I'll try to post here.
Dj series 6

[RandyL]

Wow, now that's a creative solution! Thanks, that'll give me something to go on.

How would you ever describe something like that without a pic?

[airlina]

I was mistakenly under the assumption that the new kits used the same method for stab trim position that my Series 5 has. I am attaching a illustration of my setup in two scans. It uses a 1/16th inch cable to a coil spring under the cockpit console to show trim position.

[airlina]

attachment #2