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Flap control - Auto up-down like car windows?

Snowflake

Snowflake

Sidney, BC, Canada
Sponsor
I'm sure people will tell me why this is a silly or impractical idea, but i'm curious.

My car window has a single switch to control it, that seems (to me) to have five positions. If I pull or push it lightly, I get control over where I want the window, and I can raise or lower it a little bit when I want to. If I pull or push to the limit, it goes into "auto up" or "auto down" mode, and it drives the window to it's limit before stopping.

Is something like that possible on the flap mechanism? I think you'd need a 5 position switch... on-(on)-off-(on)-on. Are those even made? I suspect in the car that it's done with a microcontroller, and a simple (on)-off-(on) switch, as even though I pull the switch all the way to the stop, when I release it the switch comes back to center but the window keeps moving.

Anyone have ideas how to implement that?
 
I am No electrician however, is there a reason a switch out of your vehicle wouldent work? Take the guts out of it, implement a new handle/knob and wire it to the motor? Im sure there is a reason bc that just seems to easy. I love the idea tho, I want to be able to hit the switch and forget about it.
-david
 
Rob, I likethe way you think.

The VP flap controller does almost the same thing. You can bump the flap switch to go to the next postion, and stop it at any time by pressing the opposite switch direction.

I have that same type of switch in my car too. Might be a bit too sensitive for turbulence though.
 
Do you really need (want) both a hold and a "bump" option in both directions? Do you want to reduce a flap setting by a bit, or is up flap an "all the way" function?

If it's a quick, "all the way" retract option you want, then a ON-OFF-(ON) switch would work with the momentary (ON) being in the down direction.

The addition of an up-limit microswitch will give you this function with only a simple inexpensive change to the flap circuitry - circuits are here on VAF.

Some certified planes are wired this way, enabling a quick tap of the flap switch to fully retract the flaps for a go around.
 
"I think you'd need a 5 position switch... on-(on)-off-(on)-on."

I looked for a part like that recently -- I even asked 'lectric Bob about it -- but no dice. DP5T switches aren't too common, unfortunately.
 
I would be afraid of a full auto-up flap switch.

I was in a '65 Cessna spam can going into an unfamilliar airport at night. I decided I was too high and needed to do a go-around. I established a positive climb and reached over to bump up the full flaps to half. This was the old sytle toggle switch. The flaps fully retracted and caught me off guard. ( I guess the switch stuck). Not knowing what was ahead in the black abyss really concerned me as I began to sink.

I like my simple toggle in the -7A. No auto up for me.
 
AltonD said:
I would be afraid of a full auto-up flap switch.

I was in a '65 Cessna spam can going into an unfamilliar airport at night. I decided I was too high and needed to do a go-around. I established a positive climb and reached over to bump up the full flaps to half. This was the old sytle toggle switch. The flaps fully retracted and caught me off guard. ( I guess the switch stuck). Not knowing what was ahead in the black abyss really concerned me as I began to sink.

I like my simple toggle in the -7A. No auto up for me.
Click to expand...

But don't most of the low wing spam cans use no flap for a go-around? ....your problem would then not be a problem...:)

I actually find it easier on the Grumman - tap the switch into the up position and forget about it, no holding it in position for 4 or 5 seconds.
 
I have FPS-Plus installed in mine and love it. You can set as many stops as you want but three is more then enough for RV flaps. It also can control your trim tab if you have an electric trim. One push that is held more than a second takes it all the way down or all the way up and I have a second (manual) switch as a redundancy and in case of failure. So far little over 300 hours on the plane and rock solid. I love it.

http://www.aircraftextras.com/FPS-Plus.htm
 
Mike and Mark, thanks for the links to the off-the-shelf options. I agree, they would probably make more sense than trying to come up with a dp5t switch. If they're even made. As I said, I suspect the car switch uses a simpler switch with a micro, but it does *feel* like it's got 5 positions.

For background, i've flown electric flap most in the cessnas I learned to fly in. They had simple toggles, with momentary up, and momentary down. You set it where you want it, and it stays there until you move it. I did fly a 172 once that had the position lever and a motor to take it there... ie. you move the lever where you wanted the flaps, and a few seconds later the motor would get it there. Handy for go-arounds, but not very good for fine control.

My manual-flap RV-6 has four positions, but I generally only use the first three. The one thing I do like, is that flap retraction is instantaneous, and extension is only slightly slower. No need to look out the window for position, I can feel it by where the handle is. I've thought about electric flap, to clean up the cockpit and get the lever out from between the seats. I suspect I would miss the quick acting flaps, but I would regain the fine control that I liked in the Cessnas... I rarely used exactly 30 degrees, or 20. I'd set something near the nominal value, and then feather them up or down to tweak the glideslope slightly as required. Kind of an auxiliary control surface.

Maybe that's not really necessary in the RV, and I should just stick with the simpler, and lighter, manual flaps... :p
 
AltonD said:
I would be afraid of a full auto-up flap switch.

I was in a '65 Cessna spam can .... Not knowing what was ahead in the black abyss really concerned me as I began to sink.
Click to expand...

I guarantee you won't sink in an RV! :D
 
The best Cessna flap switch was the one with the steps on it, so you could move it down one knotch at a time.

When I built, I couldn't find that switch for a reasonable price so I simply mounted the "stock" switch just to the right of my center throttle quadrant. With my hand on the throttle, I can toggle the flaps up or down as needed (and push the carb heat all the in).

[click to enlarge]


BTW, a three count equals 1/3 flaps. With my -9 I found it best to just put in all the flaps abeam the numbers and not touch them again. For short/soft fields, I lower the flaps to equal the down elevator. That seems to work well. The best part is no complicated working, servos, sensors, etc. required.
 
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