It's been almost two years since I first described my Sailplane Winch Solenoid Safety Buzzer in this RCGroups.com thread, and Cal Posthuma's website says that he's sold 42 kits so far. Presumably many folks have built their own from Radio Shack parts, or parts from other suppliers, as well. I was wondering if anyone here on RCGroups.com is using a buzzer and if there are any reports of one actually detecting a stuck solenoid. If so, I'd love to hear about it.



The unit in the picture was donated to the Southwest Soaring Group Of Punta Gorda, Florida. I recently built a couple more to take along to the upcoming Orlando Buzzards contest, just in case they finally broke down and added secondary solenoids to their winches. (The buzzer is of no use on a winch that only has one solenoid.)

It is also interesting to hear how many cases are reported of failing solenoids.
Jurgen.

PS: good initiative, and very neat site around it, congrats!

I've saw one stuck solenoid on a winch at a contest long ago. They were checking the winch before the contest, and they replaced it before anyone launched.

I've also seen a stuck footswitch. That's why my "Truly Redundant" footswitch has two microswitches, one for each solenoid. Since they close in sequence, one solenoid never switches any current, so there's no arcing on the contacts. It would be virtually impossible for it to stick. (I hope!! )

Roger

Last fall after just finishing a 6V motor, 12V battery winch we were running it through its paces, trying to break something. After about 2 hours of use, possibly 50 hard launches we had a solenoid failure. We had been doing launch after launch and took a break and some kids were around looking at the planes so I disarmed the winch. When we got ready to fly again I armed the winch and the buzzer sounded and the left LED lit. Got out the meter and sure enough the left brand new Cole Hersee 24037 solenoids had failed shorted. Tapping on it caused it to release but it is never to be trusted again! None of us remembered hearing the buzzer on the last launch. My only concern is why it indicated failure after we powered it back on. But even with us either not hearing or ignoring the buzzer it did its job and any winch I build in the future will have the buzzer and LEDs incorporated into the build. I keep meaning to look for a louder buzzer but just haven’t got around to it.

I also use two switches in the foot switch in series but I do not do the arm sequence like rogerflies does. The only problem is there is not anyway to verify the switches but then again I have never had a foot switch failure. I have measured the current through the switch and it is less that .5 amp and I use switches rated at 15A.

Originally Posted by rogerflies

I've saw one stuck solenoid on a winch at a contest long ago. They were checking the winch before the contest, and they replaced it before anyone launched.

Thanks! That's interesting. Assuming the winch had dual solenoids, how did they know a solenoid was stuck? Did the winch just have warning LEDs, or did it have a buzzer?

And jbrandon, thanks for your report as well.

Originally Posted by jbrandon

I also use two switches in the foot switch in series but I do not do the arm sequence like rogerflies does. The only problem is there is not anyway to verify the switches...

I think I like Roger's setup better. He's not using two foot switches in series, he's using one switch for each solenoid. Beside the reason he gives, that system, along with a buzzer and/or LEDs, will also verify that you don't have a stuck foot switch, since that would cause the same symptom and indication as a stuck solenoid.

In fact, by listening to the first solenoid energize as you step on the pedal, you can probably ensure that Roger's winch system is healthy even without using LEDs or a buzzer. That is, if you understand how it works and you know what to listen for. In a contest, I think a buzzer is the most likely warning of all to get immediate attention.

They checked across each solenoid with an ohm meter before connecting the winch to the battery.

You're correct about my footswitch. You can hear the first solenoid close when you press down a little, and the motor will run when you press down all the way. If you don't hear the "click" or the motor runs when you've only pressed down a little, you've got a bad solenoid. Of course, you have to be familiar with it to recognize the signs of trouble.

Roger

Rogerflies, you make technology looking like art and simple and functional all at same time, i learn so much from RCgroups. I would prefer the foot switch in fluo red or so, to indicate a dangerous item in the grass. No reason to camouflage it into the background
Jurgen.

Is this any better?

Roger

Yep, great signalling red, nice dragon
And now add 2 blonde provocative bimbo's some distance from the pedal so everyone will go to there and not step on the pedal by accident.
Am reworking my pedal too now, from 1 switch to 2 switches, Pict's follow.
Jurgen.

Originally Posted by rogerflies

Is this any better?

What's that little picture on the "danger" sticker? As near as I can tell, it's Godzilla getting ready to eat someone alive.

Close. It's Godzilla holding an airplane.

Roger