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Flap up limit stop switch

MSFT-1

MSFT-1

Well Known Member
I recently bought one of the Infinity stick grips for my RV-8. It has an ON/OFF/(ON) switch for the flaps. The up position raises the flaps and stays on until you flip it to the center position.

I am concerned about accidentally hitting it and running the flap motor in the up direction for an extended length of time. The motor won't drive the flaps beyond the full up position (obviously) because the worm gear is designed to stop driving the flaps when they reach the full up position. But the motor would continue to run.

As probably everyone knows, the flap motors are a bit flaky (and expensive). I would like to have a flap up limit switch to cut power to the motor when the flaps are fully up. Can someone suggest a part number and a vendor for this type of part?

thanks,

bruce
N297NW
 
As probably everyone knows, the flap motors are a bit flaky (and expensive). I would like to have a flap up limit switch to cut power to the motor when the flaps are fully up. Can someone suggest a part number and a vendor for this type of part?

thanks,

bruce
N297NW
Click to expand...


Hi Bruce

If you search for "microswitch" you will get a gazillion hits like this one, most of which will do what you want. You probably want a "NC" (normally closed) switch that opens as some part of the flap mechanism touches the little lever.

I've wondered if this isn't a good place for one of the little PTC current limiting devices. They are used AFAIK in automotive power windows to prevent the motors from pushing against an obstruction. Properly sized fuses will do this to, but this is an application prone to nuisance trips.

James Freeman
 
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Flap switch

If you are *really* worried about it, you can spring for the $225 "FPS" flap positioning system, which will stop the motor when the flaps go up, and provide two stops going down before full flaps. You can get it at Van's.

I've got it, but probably would not install it a second time, after sitting in the airplane, and seeing how easy it is to just look out the window to see the flap position.

http://www.vansaircraft.com/cgi-bin/catalog.cgi?browse=airframe&product=fps

I'm not sure this applies to all models of flap motor, but on mine, when the motor is fully retracted (flaps up), it spins freely with almost no load. Not to say it still won't overheat...
 
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I have the same set up you describe. I went to the local electronics shop and purchased two switches with activation arms about two inches long for about $7 each. They have three fast attach lugs for common, N/O and N/C.
I used one switch to shut off the flap motor at the fully retracted position and one to control the trim speed control. At the flap retract position the trim is slowed, but as soon as you bump the flaps down a tad the trim speeds up.
I can provide a picture or two and even some wiring diagrams if you are so inclined.
I copied this setup from a local RV guy (444TX) and it really works great!
Another setup, with the switches actually mounted to the flap motor shaft with adel clamps, switches as the switch arms contact the under side of the arm rest, looks promising. (Idea by Squaz)
Fell free to email me or respond here if you are interested.
 
I'm at work right now and can't post my pictures, but if you send me an email direct I can email you my setup. The advantage of my setup is low parts count and cost, two and < $5 respectively. Go to your local electronics store or brouse Mouser's online catalog and ask for microswitches. There will be plenty of choices differing mosty in the lever configuration, straight, bent, short, long, with roller and without. Most are dual throw with a Normally Open and a Normally Closed position. My set up is similar to Larry Bowen's except my switches are mounted on the shaft and the lever's make contact with the underside of the armrest

Jerry
AKA Squaz
 
Here's an update on flap limit switches. After grinding the gears out of my flap motor assembly, I have installed a flap limit switch (similar to Larry's). It's a 15A Microswitch from DigiKey. It's pretty skookum... about 4 inches long with the lever.

Only one 18 AWG wire is required to run back to the main flap positioning switch at the panel, assuming you use the fuselage as a ground point for the Microswitch. See the wiring diagram below.

I chose to do it this way because I have another use for the switched signal (Vfe alarm when flaps extended). If you want to localize wiring to the flap housing, there is another way to do this with a switch and a power diode. If anyone's interested I can post.

Vern Little, 9A

flap_switch.jpg
 
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Flap motor indicator light

An alternative is to wire an indicator light to your up drive power wire. I'm wiring an amber indicator (dimmable and testable) to mine. It will be at the top of my panel so I should see it quickly. This is much simpler than building a micro switch circuit. Downside is that I must still react whereas the micro switch will do the work for you.

Jekyll
 
Jekyll said:
An alternative is to wire an indicator light to your up drive power wire. I'm wiring an amber indicator (dimmable and testable) to mine. It will be at the top of my panel so I should see it quickly. This is much simpler than building a micro switch circuit. Downside is that I must still react whereas the micro switch will do the work for you.

Jekyll
Click to expand...


I totally agree... I have one. Unfortunately, even with the lamp at the top of the panel, it's easy to miss. After grinding the gears on a $280 flap motor assembly, I'm not taking any more chances!

Vern
 
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I've updated the previous drawing to add a switch part number. I've had a number of questions related to this, and the purpose of the zener diodes.

The diodes are there to protect the switches from inductive spikes caused by turning the flap motor off. I'm not totally certain that the motor is a bad offender, but they can't hurt.

If I were to do it again, I'd use a bidirectional Transzorb (18 or 20 volt).

Vern Little
 
I mounted my limit switch on a shop-made bracket screwed to the F902 (RV-9A) bulkhead. Since the limit switch has a long tab actuator, final adjustments were made by bending this tab.

Sorry, no pictures. My camera has gone walkabout.

Vern Little
 
I'm about to install a micro stop switch in the flap system to stop motor from running in case I forget to turn it off on my Infinity grip. My question is, once the switch trips and opens the circuit, how do I restart the motor downward with the circuit open? Seems one would need both circuits closed before the motor would operate again. Probably is simple but I'm drawing a blank on this one. Thanks in advance.
Bill Woods
RV8 QB
IO 360 A1B
 
Simplicate and add lightness

Offhand, I suggest wiring a DPST relay into the flap circuit. One set of contacts controls power to the motor. The other set of contacts is wired in series with the relay coil. The relay is held closed while the flap motor is running by wiring the relay coil (in series with a set of relay contacts) in parallel with the flap motor. The end of run switches (either the up or down switch, wire them in series and use one relay) open the relay coil circuit which opens the relay and cuts power to the motor. One set of contacts on the flap switch bypasses the limit switches so the motor can start with a limit switch open. This would require a three pole switch somewhere, I think. That is where I would start. I haven't drawn out the circuit or chased down parts at Mouser, these are just general musings off the top of my head but I think this principle (called a latching relay) could work. I think there are relays made especially for this purpose. I chose not to do this on my project because it adds weight, takes up space, cost money, adds complexity, and adds more points of failure with two modes of failure (flap motor doesn't run or flap motor runs away). Each to his own. Hope this circuit makes sense to you. It barely makes sense to me when I read it, but I have done this type of circuit before and it can be made to work. :D
 
Toy schematics...

decathlon737 said:
I'm about to install a micro stop switch in the flap system to stop motor from running in case I forget to turn it off on my Infinity grip. My question is, once the switch trips and opens the circuit, how do I restart the motor downward with the circuit open? Seems one would need both circuits closed before the motor would operate again. Probably is simple but I'm drawing a blank on this one. Thanks in advance.
Bill Woods
RV8 QB
IO 360 A1B
Click to expand...
Toys to the rescue again.... :)

How many guys remember Meccano building toys?
Made in Liverpool till they went bust.... and sold out to the French...

This schematic for a reversing motor for toys is essentially the same as our flap circuits, but with up/down limit switches instead of an over-run clutch.

http://internationalmeccanomen.org....tationpart2bLimitSwitches/motorcontrol2b2.htm

The limit switches are NC, and open when the travel range is reached.

gil in Tucson - liked my Meccano when I was a kid... teaches you a lot about small nuts and bolts.... :D
 
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Gil: I was a Gilbert Erector Set boy, myself. I think it was similar to Meccano.

Your circuit is simpler and better than the one I dreamed up.
 
Similar...

Stephen Lindberg said:
Gil: I was a Gilbert Erector Set boy, myself. I think it was similar to Meccano.

Your circuit is simpler and better than the one I dreamed up.
Click to expand...
Yes... the Erector set was a US copy of the original Meccano set.

I was in the UK at that time, and the Meccano factory was near central Liverpool, and visiting it was a school outing.
It was also home to Hornby O and OO trains and Dinky toy cars (predecessor to Matchbox cars, just a little bigger). A great place for a school visit... :)

http://www.dalefield.com/mwes/history/index.html

gil in Tucson
 
Part number

az_gila said:
Toys to the rescue again.... :)

How many guys remember Meccano building toys?
Made in Liverpool till they went bust.... and sold out to the French...

This schematic for a reversing motor for toys is essentially the same as our flap circuits, but with up/down limit switches instead of an over-run clutch.

http://internationalmeccanomen.org....tationpart2bLimitSwitches/motorcontrol2b2.htm

The limit switches are NC, and open when the travel range is reached.

gil in Tucson - liked my Meccano when I was a kid... teaches you a lot about small nuts and bolts.... :D
Click to expand...

Hi Bill,
My Air Tractor has two limit switches for up and down stops. I just replaced one because the flaps wouldn't come up. Buy a good one with this part number: BZ-2R5551-A2 from any Air Tractor dealer or maybe Spruce. Don't go Radio Shack.

Regards,
Pierre
 
Switches

This is a copy from another posting of mine. As stated above, you need good switches, especially since the limit switch sees the load current of the motor. A 5 Amp DC rated switch should be OK for us...

------------------

You might be better of using true Microswitches (made by Honeywell) for this application, similar to the gear switches in certified planes.

642-1117.jpg


This is an unsealed version, but should be OK if it's under the canopy away from any possible water entry. Sealed versions are available. Each switch has both NC and NO contacts.

They are not very expensive, and can be bought at Mouser...

http://www.mouser.com/catalog/631/1346.pdf

This Allied Electronics page give the DC contact rating, at 5 Amps it should be able to drive your lamps.

http://www.alliedelec.com/catalog/pf.asp?FN=969.pdf

------------

UPDATE

The Cherry switch part number given in the thread link of the previous post does not seem to have a DC current rating.

Some of the Microswitch parts do, and some are AC only. This Honeywell chart will let you check distributor part numbers for the current rating...

http://sensing.honeywell.com/index.cfm?ci_id=133870&type=doc&docId=111781

The AC rated switches may work fine, but if you are buying a new switch, why not buy a correctly rated one since it does switch the fairly high motor current?

hope this helps... gil A
 
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WHY NOT JUST......

decathlon737 said:
I'm about to install a micro stop switch in the flap system to stop motor from running in case I forget to turn it off on my Infinity grip. My question is, once the switch trips and opens the circuit, how do I restart the motor downward with the circuit open? Seems one would need both circuits closed before the motor would operate again. Probably is simple but I'm drawing a blank on this one. Thanks in advance.
Bill Woods
RV8 QB
IO 360 A1B
Click to expand...
have a light that will tell you that power in applied to the flap motor? :D KISS... Are you worried that you will hold the switch on too long?

Van used this type of drive unit so you would not have to install limit switches. :cool:
 
gasman said:
have a light that will tell you that power in applied to the flap motor? :D KISS... Are you worried that you will hold the switch on too long?

Van used this type of drive unit so you would not have to install limit switches. :cool:
Click to expand...

The idea of the limit switch is that if you have to dump flaps for a go-around, or after touchdown, you can flip the switch [an (ON)-OFF-ON] type and let the flaps come up on their own without holding the switch in the UP position. This frees your right hand for other useful functions.

I had a flap light that showed me whenever the flaps were running, but this was not good enough to prevent me grinding the gears out of the flap motor mechanism. I suppose that if I had installed the flap motor properly this may not have happened. Nevertheless, the flap limit switch for the UP position is very useful, for the reasons stated above. Some Cessnas work this way.

I also used the same limit switch to build a "Flaps Deployed" alarm that provides an audio tone whenever I exceed Vfe with the flaps extended. In my 9A, Vfe is only 78 knots, so you have to be careful.

I haven't commercialized the flap speed warning alarm, but it involves a microprocessor listening to the Dynon output stream. One could also use a pressure switch on the pitot/static system, but that's more complex.

V
 
Grummans too...

vlittle said:
The idea of the limit switch is that if you have to dump flaps for a go-around, or after touchdown, you can flip the switch [an (ON)-OFF-ON] type and let the flaps come up on their own without holding the switch in the UP position.
.....
Nevertheless, the flap limit switch for the UP position is very useful, for the reasons stated above. Some Cessnas work this way.

IV
Click to expand...
This is exactly the operation of the flap switch in my Grumman Tiger... and is quite convenient as Vern says.

gil A
 
Vernon Littles' Schematic exactly shows the wiring for the switch. At first I didn't get it but after giving myself the two minutes of attention it needed it exactly shows the wiring I've been trying to describe all afternoon. In that schematic the micro switch is completely removed from the up flap circuit allowing it to reset itself as a closed circuit for it's next use. The diodes are a nice touch.

flap_switch.jpg
 
What I don't like about this is the rigging...

The hardest part of this is the installation and adjustment of the switch. Pretty hard to get it adjusted so the flaps stop exactly when they should. To soon and they are not retracted all the way, to late and the motor continues to run (except now you are not aware of it). These style micro switches are not really designed for precision adjustment and repeatability. Personally I like my flap switch just the way it is, it's simple and easy to get to with my thumb while my hand is on the throttle. Just my 2c.
 
Huh...

Walt said:
...
These style micro switches are not really designed for precision adjustment and repeatability.
....
Click to expand...
Similar switches are used for the retractable gear in many (most?) certified aircraft....

gil A
 
This may be true...

az_gila said:
Similar switches are used for the retractable gear in many (most?) certified aircraft....

gil A
Click to expand...

True enough, and I didn't say they weren't reliable but it's the adjustment that is the problem for the RV. On most retract these switches are activated by the break over of the drag links or some variation which is far from a "fine" adjustment. Trying to get your flaps to stop at exactly "0" degrees (I don't want my flaps at 2 or 3 degrees at cruise) is a different matter than a gear activated switch. If you've done it and it works for you that's fine but for me it just seems like more stuff that really isn't necessary.
 
TIME IT OUT!!

Walt said:
The hardest part of this is the installation and adjustment of the switch. Pretty hard to get it adjusted so the flaps stop exactly when they should. To soon and they are not retracted all the way, to late and the motor continues to run (except now you are not aware of it). These style micro switches are not really designed for precision adjustment and repeatability. Personally I like my flap switch just the way it is, it's simple and easy to get to with my thumb while my hand is on the throttle. Just my 2c.
Click to expand...

If you need it, you could time it out with a time delay relay. The flaps go all the way up, the clutch slips.... the relay counts down a second or two then shuts off. You could get away with a correct size capacitor instead of the relay.................................... ;)
 
Mounting

Walt said:
True enough, and I didn't say they weren't reliable but it's the adjustment that is the problem for the RV. On most retract these switches are activated by the break over of the drag links or some variation which is far from a "fine" adjustment. Trying to get your flaps to stop at exactly "0" degrees (I don't want my flaps at 2 or 3 degrees at cruise) is a different matter than a gear activated switch. If you've done it and it works for you that's fine but for me it just seems like more stuff that really isn't necessary.
Click to expand...
Walt... it's just a matter of making a fairly solid mount for the switch (solid, not heavy.. :) ...).
The end flap positions (up and down) on my Tiger are set by microswitches bolted onto brackets that have slotted holes. They are activated by the traveller on the flap drive motor worm drive.
I believe this is fairly typical, and should be easy to replicate on a RV. These switches are built to activate at a consistent mechanical position.

gil A
 
az_gila said:
Walt... it's just a matter of making a fairly solid mount for the switch (solid, not heavy.. :) ...).
The end flap positions (up and down) on my Tiger are set by microswitches bolted onto brackets that have slotted holes. They are activated by the traveller on the flap drive motor worm drive.
I believe this is fairly typical, and should be easy to replicate on a RV. These switches are built to activate at a consistent mechanical position.

gil A
Click to expand...


The secret to getting a fine adjustment is to use a large lever switch (such as the one in the schematic) and fabricate a mount that places it a long way out on the actuator arm of the flap. A fraction of a degree then has a lot of linear travel, making it easy to adjust and repeatable. I wish I had a photo, sorry.
 
Diodes what for?

Rivethead said:
Vernon Littles' Schematic exactly shows the wiring for the switch. At first I didn't get it but after giving myself the two minutes of attention it needed it exactly shows the wiring I've been trying to describe all afternoon. In that schematic the micro switch is completely removed from the up flap circuit allowing it to reset itself as a closed circuit for it's next use. The diodes are a nice touch.
Click to expand...
I wired my other RV like that, but what are the diodes for? There are no dumb questions right? Are they "clamping diodes"? :D

That reminds me that some microswitches have small wimpy current capacity. I had to use a relay pak to trigger the motor, because of the micro switch and wimpy tiny toggle I used for the FLAP on the stick grip, which not handle the current either. My new project, I'm using a BIG panel mounted switch and no relays. I'll probably forget about about the limit switch and just hold the momentary swtich or just have to remember to turn the motor off if I use a locking switch. It's nice to be able to throw the FLAP up and let it do its thing, say on a go around. However holding the switch is not much of a chore. Also it's not like a C-150 with full flaps that can't go around with the boards hanging down.

vlittle said:
The secret to getting a fine adjustment is to use a large lever switch (such as the one in the schematic) and fabricate a mount that places it a long way out on the actuator arm of the flap. A fraction of a degree then has a lot of linear travel, making it easy to adjust and repeatable. I wish I had a photo, sorry.
Click to expand...
They make assemblies with the micro switch mounted in a heavy bracket with a spring loaded plunger/lever or rotary actuator designed for fine adjustment, with out moving the switch or bracket. The business end of the protruding plunger, that makes direct mechanical contact, has the adjustment. For example an internally threaded plunger end has a bolt/locknut that can be adjusted in/out. The micro switches them self (the electrical part and case) can be a little wimpy. The switch/bracket/plunger is more substantial than a just a micro switch hanging out. Honeywell makes very stout limit switch assemblies. Jets have with 100's of limit switches. They have tried to get away from mechanical switches, going to "proximity switches", solid state or hall effect type. Yes limit switch adjustments and failure are a pain, but they are a necessary evil in some cases.

The alternative to a limit switch is not have a locking-up flap switch (you have to hold it) or a RUN on light that tells helps remind you the flap motor is running. The down side to more switches, greater chance for a failure. If you use one pick carefully and get a heavy duty one.
 
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up limit switch circuit

fwiw, i did mine exactly like vern's, except that i interrupted the +12v with the limit switch, instead of the ground. with an all-metal airplane the frame of which is at ground potential, it seemed like the thing to do. i'm sure it doesn't matter much, but i feel better ;)
 
Clarification of thread...

For those who are not familiar with the motor/jackscrew used on RV flaps, I want to clarify. The title of this thread is "Flap up limit stop switch", which is (unintentionally) a bit misleading.

The up limit of the system is mechanical, and is internal to the jack screw. If electrical power is maintained, the motor can and will continue to run once its mechanical limit is achieved. The mechanical adjustment to the flap linkages is then made to position the flaps in the up position. Same goes for the down limit.

So, the point of this thread is for those who don't want a simple spring loaded switch on the flaps, instead opting for some sort of electrically latching system.

I personally like the simple solution here - a spring loaded switch right next to the throttle. Ones hand is generally on the throttle during flap operations anyway, so it is easy to thumb the flaps up or down as much or as little as necessary.
 
gasman said:
Van used this type of drive unit so you would not have to install limit switches. :cool:
Click to expand...

Actually if the RV flaps come down too far they can catch on the top wing skin on the way back up and do terrible damage (and it's quite common). When this happens and you ring Vans for advice on how to prevent it happening again they apparently recommend limit switches, as only a limit switch gives you the flexibility of precisely determining the angle of down flap.

See this thread on the subject: http://www.vansairforce.com/community/showthread.php?t=36997&highlight=flap+actuator

I have posted a few pix of my flap actuation device which incorporates limit switches (and relays so that the heavy juice for the flap motor is not going through the limit switches).

I stole this idea from Terry Daff (we all stand on the shoulders of others ;)) and modified it to include a third limit switch (ie one for up travel limit, one for down travel limit, and one for sensing flap activation as required for my AFS Angle of Attack system).

The advantage of the system is that you can slide the spiggots that activate the limit switches up and down the push/pull rod and fasten them into position via cap screws to make any adustment of flap angle required. The system attaches to the rear face of the flap housing via a hinge.

Of course I've never flown with it...but it sure works OK on the ground for what it's worth. :) Admittedly it was a fair bit of work crafting all the parts by hand so it's not a solution for the impatient builder.:p

SYSTEM ARM



FLAPS DOWN


FLAPS UP
 
Larry Bowen method

I really like the Larry Bowen method - makes it very easy to adjust.

 
Captain Avgas said:
Actually if the RV flaps come down too far they can catch on the top wing skin on the way back up and do terrible damage (and it's quite common). When this happens and you ring Vans for advice on how to prevent it happening again they apparently recommend limit switches, as only a limit switch gives you the flexibility of precisely determining the angle of down flap.
Click to expand...

If the flaps are set up as per plans, they will be set to match the wing. And the down stop will be at the extended end of the travel. The problem is, there is enough play in the linkage that the flap can be pushed just a little bit lower than the motor set it. That is when the leading edge will pop out and catch the wing skin. This can happen if someone leans on the down flap as they look into your aircraft.

A limit switch is what is needed to solve this problem. I would place the limit switch to control the extended amount. Adjust it so the flap will not extend too far. You should have no problem using just a limit switch with the small draw of the flap motor.

On manual flaps, it's all where you cut the lower notch...........:D
 
rv8ch said:
I really like the Larry Bowen method - makes it very easy to adjust.
Click to expand...

Larry has a very simple system indeed and there is a big advantage in simplicity. I like Larry's system however it seems to me that his system does not incorporate a flap down limit switch (I'm presuming this is an RV8 which is of course quite different to an RV7 in the flap mechanism). And of course having no down limit switch means that you cannot control the angle of the flaps when they are extended (thus the chance of buckling the wing skin).
 
Captain Avgas said:
And of course having no down limit switch means that you cannot control the angle of the flaps when they are extended (thus the chance of buckling the wing skin).
Click to expand...
Sure, you can control the angle of extended flaps with only an up limit switch. Adjust the up limit switch to stop the flap motor exactly when flaps are fully retracted; the down limit is then determined by the flap motor actuator release point. Too far extended when down? Just lengthen the flap motor actuator rod end, or shorten those rod ends connected directly to the flaps, and re-adjust the up limit switch to again stop the flap motor exactly when flaps are fully retracted. Iterate this process until the flap extended angle is what you like.

That's how mine (and lots of others) are set up. Works great.

--Paul
 
gasman said:
If the flaps are set up as per plans, they will be set to match the wing. And the down stop will be at the extended end of the travel. The problem is, there is enough play in the linkage that the flap can be pushed just a little bit lower than the motor set it. That is when the leading edge will pop out and catch the wing skin. This can happen if someone leans on the down flap as they look into your aircraft.
Click to expand...

My 6A also uses the end of travel for down flaps. While weighing the plane, it slipped backwards off the scale ramps, and the flap which was in down position, hit a helpers leg. No bent flap, but it didn't push down far enough to release the top skin either. With my plane, I see no reason for limit switches at all. I do have the spring loaded flap switch by the throttle.

L.Adamson
 
L.Adamson said:
My 6A also uses the end of travel for down flaps. While weighing the plane, it slipped backwards off the scale ramps, and the flap which was in down position, hit a helpers leg. No bent flap, but it didn't push down far enough to release the top skin either. With my plane, I see no reason for limit switches at all. I do have the spring loaded flap switch by the throttle.

L.Adamson
Click to expand...

AND THAT'S THE WAY IT SHOULD BE.........

Not all installations will need a limit switch..... After you have your flaps set, lower them into the lowest position and then push on them. If they pop out past the wing skin, then you will need a limit switch to reduce the down travel.
 
There is a plans option....

gasman said:
AND THAT'S THE WAY IT SHOULD BE.........

Not all installations will need a limit switch..... After you have your flaps set, lower them into the lowest position and then push on them. If they pop out past the wing skin, then you will need a limit switch to reduce the down travel.
Click to expand...

...for the RV-6 to use a wider hinge on the flap/rear spar if needed to fit. This might place the flap a little further aft from the rear spar.

I wonder if this has anything to do with the skin catching problem, or is just a general indication of tolerance problems in that area?
 
Never noticed that before....

az_gila said:
...for the RV-6 to use a wider hinge on the flap/rear spar if needed to fit. This might place the flap a little further aft from the rear spar.

I wonder if this has anything to do with the skin catching problem, or is just a general indication of tolerance problems in that area?
Click to expand...

Good catch Gil.
I bet it is the later. Wouldn't a wider hinge worsen the problem? I am having trouble visualizing it.
I would be curious to see the difference in the top wing skin overlap, flap, and flap hinge geometry comparing a 6 to a 7,8,9. I have not heard of any
6's having this problem. I think all models use the same actuator which is held over from the original 6 design. Is it possible that the tolerances are different?
Scott M., if you see this and are so inclined, what say you?
 
This is how I did it

I built one bracket for the flap uplimit switch that also mounts the flap position switch used for my trim speed select signal. This is mounted on the passenger side of the baggage compartment just above the flap actuator arm. The switches are actuated by the arm itself. I have a similar bracket and switch on the driver side for the AOA flap position sensor microswitch


IMG_0948.jpg


IMG_0969.jpg


Not flying yet, but I will adjust the linkage so that the motor downlimit prevents the flaps from dropping too far and catching the wing skin on retraction. The uplimit will be set with the heavy duty microswitch allowing me to use on-off-momon switch for the panel. I like the dump and forget feature for flaps up based on my Mooney flying experience.
 
frazitl said:
I like the dump and forget feature for flaps up based on my Mooney flying experience.
Click to expand...

Same here - I flew a M20C with the hydraulic flaps and loved that part. I flew a C172 a couple weeks ago with a 3-position on/off/momentary switch for lowering the flaps on momentary, and for retraction simply push it up and leave it, the stop switch cuts out the motor. That was my first experience with that type of flap switch, and I liked it.
 
Garage Guy said:
Sure, you can control the angle of extended flaps with only an up limit switch. Adjust the up limit switch to stop the flap motor exactly when flaps are fully retracted; the down limit is then determined by the flap motor actuator release point.
--Paul
Click to expand...

So many good ideas. It makes me wonder how anybody built a decent amateur-built plane before the advent of the internet.
 
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