SS trim position sensor?

[RandyL]

Yep, that's a totally mechanical indicator, interesting. In this day and age though it is so much easier to provide that function electronically. With the Ray Allen POS-12 sending a signal to either an LED indicator, or my EFIS box, there is only a wire to run and nothing to ever get out of adjustment or break.

Thanks for posting the pics!

[jdmcbean]

We will be working on a solution to this. The orginal system that was used on the Series 5 and 6 aircraft while effective had some issues (slippage mainly) Some worked well and others didn't.

With the avionics equipment today we have the opportunity to send a signal to the avioincs for trim indication.. That same signal could be sent to a LED read out for those that have their panel setup conventionally.

Hopefully have something towards the end of the year if not sooner.

[RandyL]

Hooray, I don't need to spend any time engineering my own solution!

[wadeg]

What about a failsafe indicator....very small rear-view mirror (like the ones for watching crumb crunchers in the back seats of minivans) mounted on the carry through tube? Put a few small marks on the leading edge of the vert stab to line the front of the horz stab up with. The weight of the little self adhesive mirror and tape less than gadgetry way back there and something else to go wrong.
Don't know that an indicator would be useful except for before takeoff anyway. It all becomes based on feel after you start beating the air.

[DanB]

In my opinion, whether one uses an electronic indicator for their servo position or not is a non-issue. My trim system will have the LED indicator on the panel. What I consider to be more along the lines of concern in this arena is the possibility of a runaway trim.

There have been several occurances of a trim servo going south throughout the years on various aircraft... enough apparently for some to develop a safety switching box that claims to counteract a runaway servo. While these added systems may be fine, I believe I have found a simple solution on Bob Nuckoll's AeroElectric site. I took one of Bob's wiring seminars a year ago which he provides across the country for a reasonable cost. Well worth the time to glean aviation-based wiring knowledge from a guy who has been around the block more than once.

You can read for yourself the article I linked above, but I like the idea of simply placing two switches in series. From what I gathered, a runaway trim is most often cause due to a switch failure. If you build your system to operate with the need to push both switches at the same time, then what would the odds be of both switches failing at the same time? Very easy solution for my very simple mind
Regards

[airlina]

To ease your mind as well, during flight testing on my Series 5, I ran the trim stop to stop simulating a trim runaway and found the aircraft flyable by manual override (read outmuscleing the stick) Slowing the aircraft or deploying flaperons will help the reduce the required stick force under certain conditions. Bruce N199CL

[RandyL]

That was my next question, and certainly a condition should be tested during every aircraft's phase 1 period. But does a Series 5 have trim tabs on the elevator or the movable HS? Intuitively I would think the movable elevator as used on the SS would have more authority. If one can still control the plane, with power/speed reduction, with the trim at the extremes of travel then any sort of runaway trim circuit wouldn't be necessary.

[RandyL]

What about a failsafe indicator....very small rear-view mirror (like the ones for watching crumb crunchers in the back seats of minivans) mounted on the carry through tube? Put a few small marks on the leading edge of the vert stab to line the front of the horz stab up with. The weight of the little self adhesive mirror and tape less than gadgetry way back there and something else to go wrong.
Don't know that an indicator would be useful except for before takeoff anyway. It all becomes based on feel after you start beating the air.

Wade,
A simple mirror with lines on the HS/VS could certainly work, but not having a completed Kitfox I have no idea if it would work. Would it work just like a rear view mirror in a car? If so that would be a great aid in formation flying too. (oh yea, I have plans for a Kitfox formation squadron )

[DanB]

In my opinion, whether one uses an electronic indicator for their servo position or not is a non-issue. My trim system will have the LED indicator on the panel. What I consider to be more along the lines of concern in this arena is the possibility of a runaway trim.

Wade, I just re-read my 2 AM post and I appologize as it came out a bit abbrasive (one of those non-sleeping nights). I think I might have read your previous and didn't understand it... My bad

[airlina]

That was my next question, and certainly a condition should be tested during every aircraft's phase 1 period. But does a Series 5 have trim tabs on the elevator or the movable HS? Intuitively I would think the movable elevator as used on the SS would have more authority. If one can still control the plane, with power/speed reduction, with the trim at the extremes of travel then any sort of runaway trim circuit wouldn't be necessary.

Randy, My series 5 has the trimable horiz stab, Bruce