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Flap Position Sensor

Phil

Phil

Well Known Member
I have seen several references about the Ray Allen flap position sensor in the RV-10.

I purchased the Showplanes version when I ordered my RV-10 fuselage from Vans.

What's the reason for everyone choosing the Ray Allen over the Showplanes version? I should be installing the FPS in a month or two and I'd like to know what I'm doing now before I invest time installing something that I'm going to regret or remove later.

Thanks,
Phil
 
Phil,
On my 10, it's two different things. The showplanes gear mechanically sets the various flap positions.

Separately, I used a ray allen POS-12 position indicator. This gives an electronic read out that my AFS efis can use to show flap position that the showplanes unit has set.

Tom Hanaway
rv-10
Boynton Beach, FL
 
Same for me. I use the RA sensor to show flap position on the GRT system. Just did not like having to look at the flap to check position when on short final and doing final configuration check. I added the sensor during my first annual.
 
Me too

I did the RA sensor also, here is a shot of the installation.

P7220006.jpg


I used the male/female pins from a "D sub" connector, with shrink tube for insulation, connection hardware straight from the radio control world.

Here is a link to a couple more photos, bit more detail.

I installed the exact same setup in a friends plane, been flying now for 3 years with no issues.
 
I think I get it now. The showplanes device is used to preset the flap positions, so when you press the switch it goes down to the next setting. The RA device is used to sense the flap position for display on the EFIS.

It looks like the RV-10 version of the SP flap position switch has 4 settings.

Retracted -> 10 degrees -> 20 degrees -> 40 degrees

Now that leads me to another question. Is "Retracted" negative 2 degrees or 0 degrees?

It seems to me that you would want one more preset flap position in the string.

-2 degrees (reflex) -> 0 degrees -> +10 degrees -> +20 degrees -> +40 degrees

Is there no point in going to 0 degrees? I think that you would want 0 degrees for take-off and not -2 degrees.

Thanks,
Phil
 
Yes, zero for take-off. If you inadvertantly have the flaps in reflex it will extend your takeoff roll a couple hundred feet.

Bob
RV-10 N442PM
 
Thanks Bob...

That's what I figured.

I'm guessing half pops you off the runway quicker? (AKA: Short field or Soft Field?)

Or is there too much drag at half to be worth much benefit?

Phil
 
You do get benefit from half flaps during takeoff at the expense of a little drag. Not unlike the Piper short/soft field technique.

There's plenty of excess power so not any real need during normal ops to do anything but 0 flaps. With that said, I spent the weekend with another RV-10 owner that regularly uses about half flaps for takeoff but he's flying off a grass strip most of the time.

Bob
RV-10 N442PM
 
Phil,
There is one more reason - The Vertical Power units can't utilize the ShowPlanes unit. If you want to use the VP flap switch, you need a POS-12. If you want a separate flap switch and not use the VP, then the ShowPlanes unit is fine.
John
 
You'll need a POS-12 even if you use the Showplane positioning unit if you want to display the flap position on an EFIS (or even one of the LED bar graph modules) versus just looking out the window. The Showplane unit just insures that your flaps move to a preset position and then stop but don't actually provide position info for external devices. This is also true for the Aircraft Extras positioning unit however the verbiage on Van's website says that the position sensor is included.

Bob
RV-10 N442PM
 
The POS-12 is optional with the VP systems. Adding the POS-12 gives you a flap position display, and also enables intermediate flap stops without having to add the ShowPlanes kit.
 
MCA said:
The POS-12 is optional with the VP systems. Adding the POS-12 gives you a flap position display, and also enables intermediate flap stops without having to add the ShowPlanes kit.
Click to expand...

Marc,
You mean I could have kept the ShowPlanes unit and still utilized the VP-200 if I had a POS-12 as well? You had advised me to sell the ShowPlanes unit.
John
 
johngoodman said:
Marc,
You mean I could have kept the ShowPlanes unit and still utilized the VP-200 if I had a POS-12 as well? You had advised me to sell the ShowPlanes unit.
John
Click to expand...


John,

The POS-12 tells the VP-200 your flap locations. The VP software allows four preset locations. You don't need the ShowPlanes unit.

bob
 
[email protected] said:
Four positions....

Reflex - 3 degrees
0 Degrees
Half
Full

I never really use anything except, reflex, 0 and full.
Click to expand...

Gents,

The online documentation says all in one direction "Three-position switch stops at approximately 10, 20, and 40 degrees (degrees of travel varies with aircraft type)"

I want to understand this right...So you can configure the the Showplanes unit to stop on 2 possitive and 1 negative degrees for the RV10? and it will always stop on Zero degrees going up or going down?

I don't want to hit auto retract on a go around miss approach and it goes to reflex -3 it needs to go to Zero...
Same that just comming out the cruise when you hit down from reflex -3 it needs to stop on Zero.

Can it do that? and does someone have a picture install of this unit?
How would one configure Reflex Flaps without such a unit? Is the Reflex worth it?

Thanks
Rudi
 
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Showplanes unit does not stop when going up - it retracts until you stop it with the switch or it hits the up limit which will correspond to the reflex (-3) position. Once there and the switch in the middle (off) position, one tap goes to neutral (0), another goes to half and another goes to full.

The standard switch is momentary contact down, spring loaded to the center position.

Bob
RV-10 N442PM
 
I opened up my Show Planes box from Vans and it's missing the switch.

What type of switch is supposed to ship with it?

I don't mind missing the switch because I'd like to choose one of my own decor. But I'd like to know which type I should get.

Anyone know?

Thanks,
Phil
 
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Standard switch is DPDT with ON-OFF-ON* positions. The * indicates momentary contact which is spring loaded to the center position.

You can find these as standard toggle switches or from a few places with a rectangular "flap" handle. Somebody was just advertising one of these on VAF that they had purchased from Pacific Coast Avionics for $90.

Bob
RV-10 N442PM
 
Question for Mike Starkey.

I like your solution for the flap sensor. I was going to do one on a hinge behind the footwell kickpanel using an adel clamp on the flap tube.

My question is, did you do the math (geometry) for the throw (arc) of the flap bellcrank vs travel (inline) of the sensor to come up with that spot on the crank or just luck out?
 
woxofswa said:
Question for Mike Starkey.

I like your solution for the flap sensor. I was going to do one on a hinge behind the footwell kickpanel using an adel clamp on the flap tube.

My question is, did you do the math (geometry) for the throw (arc) of the flap bellcrank vs travel (inline) of the sensor to come up with that spot on the crank or just luck out?
Click to expand...

I ran the flap motor all the way to the stop, and drew a line on the fuse side along one edge of the arm. Ran it all the way the other direction, and drew another line, this gave me a /\ shape on the fuse. Then I drew a line crossing the first two, making sure the included angles were equal. Lastly I measured between the first two lines, parallel to the cross line, until I found a position that gave me the correct distance to equal the throw of the sensor.

You could also just make the first two lines, measure the angle, and use trig to determine the dimension to get the correct base value. Probably how an engineer would do it.

My way is easier;)

Hope it all makes sense:confused:
 
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I was going to do one on a hinge behind the footwell kickpanel using an adel clamp on the flap tube. My question is said:
I kept my POS12 in the flap motor tunnel, and used the bottom yoke lightening hole. Put a "well nut", sometimes called an expansion nut, through the hole for a mount, then used some model airplane 4-40 stuff to attach to the POS12. You can find well nuts at your local Ace Hardware aviation department - they are made out of rubber with a metal core, a big rivnut.
The POS12 only has a 1.25 inch throw, so you need to reduce it somehow. I used a bellcrank setup. Think of a see-saw with unbalanced lengths. Mine is 4" long, with the pivot at 1.5" from one end. It changes the 2" throw from the bottom lightening hole to one inch.
John
Click to expand...
 
My time

I'm getting ready to install the POS-12 flap position sensor. I can buy the POS-12 unit direct from Ray Allen, but where can I get the clevis (2) and all-thread or threaded rod? I could probably gin it up from Ace Hardware or Lowes, but wondering if there is a source where that part can be bought ready to go.
 
dmaib said:
I got the hardware at an RC Model Shop. They will have everything you need.
Click to expand...

Correct, these parts are straight off the rack at the R/C shop.

I used ball link connectors instead of ordinary clevises to account for any misalignment that might be there.

P7220006.jpg


Go for it, only about $7 worth of parts IIRC.
 
Uhhh

Uhh, how about an online store? I don't think I have an R/C shop nearby. I'll check around, but mostly all we have in Montana is mountains and cows....
 
I wanted to bump this thread for any current -10 builders. I just now stumbled upon the fact that I actually need to install a potentiometer (ray allen pos-12 for example) to display flap position on my EFIS. This thread was very useful and so thank you to all for contributing. I'm bumping it because this was something that I overlooked because I just assumed that the show planes Flap Positioning System had a way to send the readings. It does not.
 
For future builders, here's a pic of what RV-10 builder Mike Kraus' hinge method looks like. The hinge is on the rear spar and the adel clamp is on the flap torque tube.

flap_and_aoa_switch_151.jpg.w300h400.jpg
 
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Showplanes without display

I have the Showplanes FPS. After 50 hours, it started to "slip" basically requiring me to fly the plane as if the flap is manually/visually controlled (when it gets close to the intermediate position it will run to the stop, otherwise, I have to actuate the switch and visually check the flap position.) (I know how to fix this and will do so soon).

My experience is that looking directly at the flap to determine the position is not a problem. In fact, I could argue that looking at the flap is another opportunity to look out the window rather than at those beautiful GRT displays.

I'm sharing this as a data point - you don't need a flap indicator. Having one is good too I'm sure.

I live on grass. I use the intermediate position for all TOs on grass or short. Reflex for hard surfaces (0deg if I remember to set but I can't tell the difference). I generally land with full flaps even with high xwinds. For about 100 hours I used the intermediate position for all TOs but reflex or 0deg is easier on hard surfaces.

This is a very informative thread... thanks all.

FWIW.
Bill "loving every minute of owning this fine airplane" Watson
200 hours
N215TG
 
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