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Flap limit switches

TerryWighs

Well Known Member
Wanting to install "limit switches" on my flaps. (RV-8). Anyone found a good brand or come up with an ingenious design for installation?
 
I have installed FPS on my 7A and absolutely love it. It has been about 7 years since flying with zero issue with it.
 
I'm curious as to why you want to install limit switches? When properly installed and rigged the flaps will not extend or retract too far.
 
A limit switch to turn off the motor when it is full "up" is really handy, as then you can just throw the switch to up and forget about it on a go-around. I don't have a picture handy, but I just use a bracket attached to the switch and then attach that to the actuator with a hose clamp, and set it up to hit the structure when you hit full up on the flaps. Been working perfectly, without adjustment for 12 years and 1800+ hours on the RV-8.

Paul
 
A limit switch to turn off the motor when it is full "up" is really handy, as then you can just throw the switch to up and forget about it on a go-around. I don't have a picture handy, but I just use a bracket attached to the switch and then attach that to the actuator with a hose clamp, and set it up to hit the structure when you hit full up on the flaps. Been working perfectly, without adjustment for 12 years and 1800+ hours on the RV-8.

Paul

I need to do that.
 
A switch as simple as one of these will do the job: http://www.alliedelec.com/honeywell-v7-7b19d8-263/70118567/
http://www.alliedelec.com/omron-automation-z15gw2b/70354919/

On the RV-8A I made a couple of U shaped brackets and pro-sealed them to the inside of the skin. The switch was mounded on a piece of aluminum with screws to attach to nut plates on the U brackets. The screw holes were slotted to provide some adjustment range. The switch was in place to turn off the motor when the flaps were in the full up position.

It worked, but was a PITA to get adjusted just right. The new owner removed the switch and installed the FPS system after he saw how well it worked in the RV-10. The FPS is a better way to go and it eliminates the reversing relay if you are using a switch on the stick for flaps.

The new RV-8 will also use the FPS system.

Carl
 
I did this to work with the infinity grips, as Paul describes, flip it for go around....no need to worry about how long to hold the switch up.... and overheat the motor...and have the grease drip down on brushes and stuff.......
 
Not sure if it is even a consideration for you but that is just one of the many things the VPX does for you along with a whole bunch more stuff.

:) CJ
 
Wanting to install "limit switches" on my flaps. (RV-8). Anyone found a good brand or come up with an ingenious design for installation?

Here's how we set it up on our RV-8. Pretty easy to do. I think we got that limit switch from Infinity. This was just the mockup for testing, we did clean it up in the final version! But it works very well. No issues in over a year of flying.





Here's a description of how we did it on an RV-6:

http://www.phaviation.com/?p=190

I definitely am a believer in having these up limit switches for the reasons others have already advanced.
 
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This is how I tackled it:

2agw18i.jpg


It's been flawless for 9 years/1100+ hours. One of the limit switches is to cut out the motor when my flap switch on the stick is left in the up position during a go-around/missed approach and the other switch goes to a relay that reduces the speed of elevator trim tab movement when the flaps are up.

I had some other pictures that show the detail of the bracket, but they're not easily accessible at the moment. It's a simple little bracket made of .032 or .040 that is flat where the switches are attached and curved to fit around the tube on the other end. It is attached with a simple hose clamp. The switches actuated against the underside of the armrest.
 
What say the brain trust:

Is it worth while putting protection diodes into the flap motor circuit? What about the ckts for the tinier RAC trim modules?

Edit: This pdf is a schematic of what I'm (over)thinking....https://drive.google.com/file/d/0BwUkbTq0g5PtaXdYR2ZoMXhVZVU/view?usp=sharing

Won't hurt. You could simplify slightly by using a bidirectional 15V transzorb across the motor or back to back 15V Zener diodes instead. Even a 0.1 uF capacitor would help.
 
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