Sorry still not enough info to know for sure. It would connect to the yellow and white connector but odds of it working are 50/50.

It looks like it is about .80v when on. 0 when spark fires.
A note... After the spark plug fires, the meter reads 0 for a few seconds, then about .59, then about .70, then .80. As though a capacity was being built up. Is this reading off of the capacity being built up in the ignition module possibl?
-Dave

I don't think that is what is happening. I am willing to bet that it is an open-collector or open-drain output. What that means is that it connects it to ground when it sparks through a transistor. Otherwise it is "floating" ie the transistor is turned off. This is the same as the hall effect sensors that the Twin sync uses. A quick and easy way to check it to plug the white and yellow wire into the black/brown and orange sensor connector on the twinsync. Try it and see if the green led functions correctly.

Although I suspect that you might likely be able to connect the white and yellow wire directly into the twinsync and it will work fine, I don't recomend it. The reason is there is probably spark noise in the ignition ground that you don't want getting into the receiver ground. You could determine this with range tests with the engines running - but in general not a good practice. The right way to do this is with an optocoupler.

If it is as I suspect then the optical couplers I built for the ZDZs will not work on 3Ws. You will have to wait on month or so until I have the new ones.

Thanks Bill. I'll wait until I am absolutely ready to go. I figure first runs will be late spring. Mean time I'll keep an eye on the thread. I appreciate your time.

- Dave

So this sensor could hook directly to a magneto engine and be opti isolated?

I have 2 new stock G-38's with magnetos, and wanted to use the fema on board starters that hook up to the crank @ the rear.
No room for the recomended sensor install at the rear, cant get the standard hall effect sensors anywhere near the magneto up front for a spinner setup.
Cant put up front, cant put in back, dont want to spend $400 to swap out to electronic ignition on 2 new engines.

Could you make a opti iso pulse sensor that piggybacks on the plug wire for me?

Ted



how cool would these be!

Actually Ted,
You could install in rear..
Put magnets inside larger ring gear
and mount sensor on starter motor bracket..

I think that ring gear is after the one way bearing, i.e. its dosent spin with the crank, it only spins when the starter is engaged. The free-wheel one way bearing sits right on the rear crank output shaft. From what I can tell from the parts views from FEMA.

Ted

Bill and everyone with ideas,

The sensor is a very small seamingly fragile piece. Does anyone (BILL) have any suggestions (pics would be great) of just how to mount the sensor to the motor?

Thanks,

Dave

Just thinking out loud here....

Looking at your pics, wouldnt it be super clean if you could get another rpm hall sensor and mount from the manufacturer (the one used for the ignition crank trigger) and bolt it to the other side of the crank, utilizing the same magnet?
idono, just a thought.

Or...
I was thinking if I had to use a spinner mounted magnet, to get a half of an old 2 peice nylon engine mount (pref. a long one) mount it to the firewall (with a spacer block on the firewall if needed) with the sensor at the other end by the spinner. This might work if you are using a large diam. spinner.

Ted

The sensor is fragile. That is why I recomend encasing it it glue (epoxy, shoegoo, etc) once mounted so the solder connections of the wires is supported. There are a ton of pictures and recomended mounts in this thread. Scan through the thread and you will probably find a method you like.

As for sensing the magneto or spark - Not on the immediate horizon but I am toying with an idea for an device that will measure spark voltage and number of sparks (i.e. to be compared with number of crank turns for analyzing ignitions). Not near term though.

P.S. Only use the hall sensors supplied with the TwinSync -
they are special - not just basic hall sensors!

Ted,
I had thought about doing that very same thing with the sensor. After much debate (because the sensors are $45 a pop) I decided I did want a clean, reliable way to mount the sensor to the motor so...

I got the factory sensors, gutted the mounts and cleaned them up. I mounted the TwinSync sensors in the 3W sensor mount, loaded the insides up with epoxy resin and then mounted them to the motors.

-M51

M51, what material is the 3W sensor made from and have you tried the twin sync yet with this setup? As one of the oringinal beta testers for the Zenoah engines, I had no luck using metal bracket standoffs to hold the twin sync hall sensors on the G-26's. I had my magnets in the spinner backplates. The hall sensors were JB welded to the brackets , but appeared to produce inconsistant sensor pulses to the twin sync. I believe it was too close to a ground source, and remember, JB Weld conducts electicity. I wish I could remember the exact symtoms incurred using the metal brackets, but when I switched to thick plastic brackets, the twin sync worked fine. If you only have 1 North pole magnet on that 3W crank, and the sensor mount is made from non-conductive material, it should work fine. Let us know. Thats a nice clean setup and that technique may also work with the Revolution GT-26. Rick Simmons

M51, I ment, what material was the 3W sensor MOUNT made from? Rick

Hi Rick,

The mount is made of a heavy plastic except where the magnet pases which is rather thin as you would expect. This particular ignition set yp uses two magnets mounted in the hub. One is north, the other south(or green and red. I don't know which is which). I think the reason for this is that 3W offers an on board tach that I think keys off of the opposite magnet that the ignition does. I could be wrong.
The Twinsync sensor will key off of either depending on what side of the sensor you use. I chose to key both motors off of the same magnet (green) to keep things straight.

-Dave

Dave , OK, that should work fine.....but have you run the engines yet with the twin sync plugged in? If it lights the green LED's when you roll the engine over, then it's talking to the twin sync. If you have any issues, first confirm that the hall sensors have not been dislodged from vibration. You should have between 1/16' and 1/8" air gap between the hall sensor and magnet. Use red loctite on the mount bolts because they are permenant...... Let us know. Rick

Bill,

I recently ordered a new Twinsync for my KMP Tigercat. I am using two RCV 120SPs for power. After reading the instructions for mounting the magnets and sensors I am unsure if I can make this work. I don't know if you are familar with this engine (pictures on KMPs web site) but the prop hub has cooling fins. As far as monting the sensors; the body of the engine tapers all the way down to the prop hub. Any suggestions??

I looked at the picture and I see what you are talking about. I was hoping someone else in the forums might chime in. How close can you get the sensor - an 1/8" would work? You could drill the hole through the fins rather than the hub then jb weld it in but should probably rebalance after that. The other thing is you can always put a small disk behind the prop and use the spinner magnets in the disc.

Hi, I just installed a Twinsync on two .36s for a Hangar 9 B-25. I've been bench testing them and the synchronization works great. The dead engine feature does not appear to be working at all though. If I have both engines running at a considerably high speed (well above 1500 rpm), and I pinch the fuel line on EITHER one to kill it, the other engine just continues to run at the speed it was at. It doesn't bring the other one down to idle at all. I have tried resetting the idle point, that didn't work. I have no idea what could be wrong, I've re-read the manual and can't see where I'm screwing up. Any ideas?

when you pinch the line, are you holding it untill it dies?

Email me your phone number. I have never had a report like this before. I am very interested in getting to the bottom of this one since this is a key feature of the product and never had an issue.

Are you getting two yellow leds while synchronizing? If not then you may be below the sync point and you may need to reprogram the sync point. There are some customized units out there with this feature disabled. I know who has them though. You did buy it new from RC Showcase didn't you?

Yeah, holding either one until it dies. Observing to make sure that the magnet on the dead engine doesn't end up in front of the hall effect sensor too.

Thanks for the call Bill. I knew it was me that was committing the error, not the Twinsync. I guess I hadn't read carefully enough to know that each of the green lights is supposed to come on as a magnet passes by the corresponding sensor. One of the sensors wasn't picking up the magnet (i.e. no green light), so I flipped it over and presto, it got a reading (green light came on). What I had thought was synchronization before was really just nothing, coincidence that the motors were running relatively near each other. Now it is perfectly synced up and the dead stick feature works fine, I tested it with either engine. Great product, and even better technical support!

Can't wait to get that bird in the air and hear those motors doppler by.

I got on this late. I don't know if this has been covered. Is twinsync useable with electrics?

Yes -- it should work fine on electrics. Most of the development was done inside on the bench with a pair of brushless motors and ESCs. Glow and Gas were tested extensivly but development was done on electrics. However, Do you need this on electrics???? I guess if one fails but otherwise are they not pretty close to being synced?