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Flap switch conflicts

RVG8tor

RVG8tor

Well Known Member
I have searched the board but can't find anything specific to my question. I want my back seat grip controls to mirror the front other than the start button. My concern is with the flaps, since the switches can be in the up position, off is momentary. I have the flap control relay broad from vans. If one flap switch us up and the other is actuated to down will this burn the relay board, I am thinking that it would? So how do you control the conflict between the two flap switches?

I know TCW sells a flap controller that solves this issue, I already have the Safety Trim and Smart Start, I just want to avoid spending another $225 if there is a simple solution. I already plan a rear trim and flap lockout switch for when I am flying inexperience folks. I want the full controls for when it is me and another pilot.

Thanks for any advice or help.
 
I can't find a schematic of the Van's relay board, but if it is like Rosie's drawing here:
http://vansairforce.com/community/showthread.php?t=18372
you should be able to put the switches in parallel.

If the pilot switched one way while the copilot switched the other, it should ground both sides of the motor, resulting in a stop, not a short circuit.

If you want to take a chance, you can try it out, but it is taking a chance without more information.
 
You could rig up a trial circuit with an LED that glows green or red depending on the current direction to check it out. No risk.

I'm not certain but I think their 276-012, for $1.69, would do the job.

Or just use two ordinary LEDs, in parallel, set to turn on opposite each other - they only turn on with the current in the right direction, and aren't hurt with small current in the other direction, if I remember correctly.
 
Disable switch

Daniel Hooper said:
I can't find a schematic of the Van's relay board, but if it is like Rosie's drawing here:
http://vansairforce.com/community/showthread.php?t=18372
you should be able to put the switches in parallel.

If the pilot switched one way while the copilot switched the other, it should ground both sides of the motor, resulting in a stop, not a short circuit.

If you want to take a chance, you can try it out, but it is taking a chance without more information.
Click to expand...

I saw Rosie's drawing doing my search but it appears to only have one stitch in the circuit. I want two operational flap switches but I don't know how to wire it so that they will not conflict with one another.

I think I am at the point where I will just have a disable switch for the rear stick. When I am flying with someone who knows what they are doing I will enable the controls. I will be in one of the seats so I will make sure my flap switch is off then let the other guy fly with his controls. Besides, only one person should have the controls at a time. I know this is not fail safe but it does what I want cheaply.
 
If both switches were mom-off-mom it would work.

But, you would loose the ability to "hit and forget" the up function.

A standard switch on the front, and a mom-off-mom on the rear might do the trick, but then again, I do not know.

If you are using the Vans flap pre-positioner, you could check with Brian at ShowPlanes, or in someone else s unit, check with them.
 
on-off-(on)

Mike S said:
If both switches were mom-off-mom it would work.

But, you would loose the ability to "hit and forget" the up function.

A standard switch on the front, and a mom-off-mom on the rear might do the trick, but then again, I do not know.

If you are using the Vans flap pre-positioner, you could check with Brian at ShowPlanes, or in someone else s unit, check with them.
Click to expand...

Mike,

Unfortunately I already have my sticks, I did not think of this when I bought them.

I have this control board from Van's http://www.vansaircraft.com/cgi-bin...-160-213&browse=electrical&product=flap-board I don't' think it is designed for more than one switch. I think I will use the suggestion above and run things to a light to see what happens when one switch is up and the other is actuated to down.
 
RVG8tor said:
My concern is with the flaps, since the switches can be in the up position, off is momentary.

Thanks for any advice or help.
Click to expand...

If I am reading this correctly, and also reading the details of the Vans control board correctly, you may be in for a problem.

The Vans board looks to be only a way to handle higher current than the switch itself is rated at, it does not appear to have safety cutoff, or travel limit switches, and if your flap switch will stay in the up position, what is to keep the flap motor from running after it reaches full up travel??
 
I have the vans relay board with two flaps switches in parallel (infinity sticks ) Theses switches are on - up, off-centered and mom-on when down. I wired up two micro switches (parallel with each other for redundancy) in series with the up ckt to shut motor down at the up stops. If the rear switch is left in the up position the front switch will bring the flaps down until the micro switches are no longer in contact at which point nothing happens. I cn reach behind me to disengage the rear flap switch if I fail to check on preflight. You won't burn up the motor as no current will flow with power connected to both sides which is the case with one switch up and the other down and didn't see any change in current indicating a short through the relays.
 
Good News

RV8R999 said:
I have the vans relay board with two flaps switches in parallel (infinity sticks ) Theses switches are on - up, off-centered and mom-on when down. I wired up two micro switches (parallel with each other for redundancy) in series with the up ckt to shut motor down at the up stops. If the rear switch is left in the up position the front switch will bring the flaps down until the micro switches are no longer in contact at which point nothing happens. I cn reach behind me to disengage the rear flap switch if I fail to check on preflight. You won't burn up the motor as no current will flow with power connected to both sides which is the case with one switch up and the other down and didn't see any change in current indicating a short through the relays.
Click to expand...

I did plan one micro switch to cut off the motor for the up position. I chose the up as a non momentary position so that on a go around I could just put the switch to up and forget it, the micro switch would prevent the motor run on.

So you set up is what I am look for, just to make sure you have two up micro switches? What is the abnormal that made you want an additional back up.

Also do you have a rear stick disable switch? I have read that you can combine the grounds from the trim and flaps to one side of a switch, by cutting out the ground to the rear stick you effectively make the rear stick inoperable for these switches. At least that is what I think will work. I am going to hook up the stick on the table and try my theory out before I intall them that way in the plane.
 
What Ken said

I hooked up both stick on the table and they work as Ken said. If the flap switches are opposite then the motor just stops. The switch on the ground wires to the rear switch does disable the flap and hat switch.

The only procedural gotcha that I have found is:

Flaps down any amount
Rear flap switch in the up position

If the rear stick is enabled with this configuration then the flaps will immediately move up.

Most likely if the person in back is flying the pattern the switch would have been enabled prior to flap deployment, there is no problem with the up position and enabling the rear stick as the micro up switch would not power the motor.

So procedurally there will be a step to ensure rear flap switch is off prior to enabling rear stick controls.

Thanks for the help. It seems with me and electrical stuff, I have to hook it up to see it work.
 
RVG8tor said:
So procedurally there will be a step to ensure rear flap switch is off prior to enabling rear stick controls.

Thanks for the help. It seems with me and electrical stuff, I have to hook it up to see it work.
Click to expand...

As I mentioned before, you could use a momentary switch in the rear for up-----that way it will never be left in the up position.
 
Already have stick

Mike S said:
As I mentioned before, you could use a momentary switch in the rear for up-----that way it will never be left in the up position.
Click to expand...

Mike,

I already have the infinity sticks, I am not too keen on soldering in a new switch, but you are correct that would eliminate the issue when enabling the rear stick controls.
 
Mike,

I would need more info to help you figure out a solution. There are a couple options that I can think of:

1) Use a switch which enables the front stick flaps in one position or the rear stick in the other position. This will prevent the short posibility. It doesn't prevent the problem that they could be in different positions. This creates a manual selector.

2) Use a couple of diodes to create a logical OR function. If either stick is in the +12V position then the output would be +12V. I'm talking in generalities here I don't know how your controls work on the output of the switches. I could help you with this approach if you want. The diodes protect you from a direct short when the two switches are in different positions. Think of it as if front or rear is on its on. This doesn't allow you to turn off the rear, but you could always add as switch to the wire from the rear for that funtion so you could always get control back on the front stick if you had to.

Hope this helps.
 
RVG8tor said:
Mike,

I already have the infinity sticks, I am not too keen on soldering in a new switch, but you are correct that would eliminate the issue when enabling the rear stick controls.
Click to expand...

Got it, I understand the dilemma now.

Bit dense sometimes:confused:
 
copilot grip disable.

I have multiple flap switches wired to the Vans Flap board, which btw is really made by Advanced Flight Systems. As noted before, if any two switches are in conflict, it doesn't do anything bad - just stops the motor.

For the question about how to deal with the problem of the rear seat being stuck in the ON position, Mike's idea for the momentary was a good one, but here's another easy solution:

I wired up a switch in the panel that disables the motor functions on the copilot grip, including flaps, trim, and smoke. This switch generally stays in the off position because there's not usually a need for this from the right seat. I did this primarily to prevent young kids or fiddly passengers from causing any harm if they messed with buttons in flight. This would also be another way to deal with the problem in the tandems that the flap switch is stuck in the on position. Just disable the grip and the position of the switch becomes irrelevant. (PTT is not disabled - just motor functions)

All you need to do to disable the motor functions is run all those ground wires to a switch. In the ON position, the ground wires are connected to ground, and the copliot grip is enabled.
 
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