Together with scale C/L flier Joe Eiben, I've developed gear and flap and general servo controls for non-electric planes (see also the latest Control Line World for the article by Joe). There are separate version: GM-1 for multiple gear retraction/extension, the SM-1 for actuation of any standard servo (bombs, etc.), and the FGM-1 for sequential raising of flaps (totally smoothly over a period of 4 seconds) and gear, and lowering, etc.

The controllers are powered by a standard 4-5 volt battery and actuated either by a microswitch at the extreme motion of a 3-wire bellcrank or by connecting two wires at the handle (with at least one insulated line).

I'll attach a picture of the FGM-1.

Will Hubin

The circuits are designed to be actuated by the closure of a normally-open switch, so anyway this can be accomplished would trigger the outputs to the servos. (I delay 5 seconds between actuations to prevent multiple cycles being triggered by the usual slow, bouncing contacts of normally-open switches.)  There is some flexibility because I usually wait for an order before "burning" the program into the microcontroller.

The gear control in the FGM-1 assumes a retract servo, and they are faster than scale, in most cases, I would guess. However, I move the flap output an increment of 1/2 of 1% of full throttle every 1/50 second, so that gives a perfectly smooth rotation over 4 seconds. A standard servo could be used with this output to get gear retraction and extension over 4 seconds, too.

The output to the servos is the standard 3-wire setup -- +5 volts in the center lead, ground and servo signal on the sides.

The microcontroller chip I use is specified for voltages up to 5.5 volts, which is fine with almost all BEC outputs; however, when used with a different circuit, with the Hacker ESC (which puts out somewhat more that), I insert a diode to drop the voltage into the specified range.

Thanks, Clancy. I thought of that approach immediately, but what I was hoping was to prevail on Will's good nature and get a version that eliminates the space/weight of an added servo and switch, plus the mounting hardware for same. This would require Will's unit to detect the 1-2 msec pulse width change and provide a binary output to the rest of the circuit so you wouldn't need the extra stuff in a crowded, overweight scale model.

If you have a couple of other functions (flaps, turrets, bomb drop, weed spray) to actuate separately, you are talking about two servos, plus micro switch for each function. That would get crowded plenty fast.

Right now, my Jenny is using two channels of the encoder/decoder, one for throttle and one for the towhook release. The ESC is taking its input direct from the decoder and the second channel is running a mini-servo attached to the towhook release. Time delay isn't an issue for this setup, however I am planning a WWII era model with throttle, flaps and retracts, and perhaps bomb drop. The flaps, retracts and bomb doors all could use a delay feature, as could turret rotation. I am sure there others I haven't thought of.

So there's my wish list, Will, and while you're at it, put four delay functions on one board and a USB interface to program it all.

John W

That's more or less what I was thinking of, just being a plain 'ol ME. Clancy's biggest unit has four channels, so two boards like you're talking about would do the trick.

This group sure has a lot of knowledge and talent.

John w

Point of Order.  LOL

The 4 channel U/Tronics Control system is not the biggest I build.  It is available with up to 7 channels when ordered.  I only charge $5.00 for each additional channel over 4 when originally ordered.

Clancy

John R,

Of course we're not talking about a huge market here, but I would be interested in such a system. I'm not a circuit designer but am handy enough with a solder iron to build something. It would be better than multiple servos.

Will,

The next project for me will likely start in late 2010. Is your servo delay machine something you'd build on request?

Thanks,

JohnW

Will,

We all owe you guys that have the expertise and energy to pursue these things that benefit the model community so much. Thanks for doing this. I'm planning on an electric twin project for the next scale plane after my Jenny is complete and it will be WWII era, so should have a use for your circuit.

I am familiar with the cost and time it takes to do what you are doing as such effort is a major portion of the development cost of the laser systems my company builds.

Regards,

John W

What I had in mind was:

A is servo siginal.  One shot B is set to 1 1/2 ms.  Output is 74LS74 Q or Q*.  When the servo drive is set to 1 ms Q should be low or gnd.  When servo drive is set to 2 ms Q should be high or close to 5V.  Q should now be able to trigger sequencer.  PS I have omitted sets and resets etc on the drawing. They need to be high or low as needed.  I probbly have the parts in my junk box to try this. If anyone in interested I will give it a go and report the results.  This would also force me to pick the R-C values for a 1 1/2 ms pluse.

Clancy,

It sounds like to me that if one put a momentary push button switch on your multy channel control handle along with the circuit I described above the extra servo could be eliminated.  With the push buttion in its normal state (not pushed) the servo output for that channel would be a 1 ms pulse. When you depress the botton the the servo signal would go to 2 ms. Releasing the button would return the signal to 1 ms.  The only question remaining is will a TLL interface signal trigger the sequencer? As best as I remember TTL will sink 8ma and is guaranteed to be .5v or less.

Wow,
It appears that a couple of engineers have hijacked this thread (yes that includes me). I think Will Hubin’s original intent, for his sequencer, was to control flaps and gear without a bunch of complicated electronics. As I see it, if you have a Clancy system, (or your own version as I have) you don’t need a sequencer.  By turning a knob on the control handle slowly you can run a servo function at any speed you want.  However this takes a boat load of electronics with all of its extra weight, insulated lines, and etc.  On the other hand Will’s module allows one to add a bunch of function with minimal hassle.  Don’t get me wrong Clancy’s system works great. As an electrical engineer with 40+ years of experience I applaud Clancy for providing the U-Control Scale community with a system that works great at a reasonable price.  However if you are a purest and want to control your throttle with a 3 line mechanical setup it looks like Will Hubin has nailed it for adding flaps and retracts.  Way to go Will.
    

PS.
Be careful of thinking that you can get away with one insulated line. The problem is unequal line drag. If the two lines are of different diameters the larger line acts as a sail making it very difficult to control the model. This is especially true during slow flight when line tension is low.  I know this is true because I have lost one aircraft and damaged another before I figured out why.  In both cases I had the one insulated line as the up line.  When throttled back the drag on the up line caused the aircraft to clime as it headed into the wind. Wind got under the aircraft and the lines went slack….. Kaboommm