RE: Eletronic engine syncronizer **SUPPORT **
 

My Hobbico TwinStar has throttle linkages that prevent setting end points @100%. It needs reduced E.P. of around 70%
In the process of setting the TwinSync's throttle (selector switch position 5) I've somehow screwed up the synch function.
LED3 now only comes ON near W.O.T. instead of 20% throttle.

How do I reset/restore that?

RE: Eletronic engine syncronizer **SUPPORT **
 

Responses:

Glow plug wires are connected the following way:
RED: Glow battery + terminal
ORANGE: Glow plug positive terminal (tip)
Black/Brown: Battery - terminal and Engine case/ground
see manual for one or two battery wiring diagram...

Sync point and end points:
Any airplane can be set up for longer end points (you may need to use a smaller servo arm though). If the servo arm has limited movement then move the throttle pushrod further out on the throttle arm on the carb.

So here is how you reset the position 5 programming:
1. set up plane mechanically to use at least 100/100% end points.
2. Install TwinSync. Power it on with rotary switch in position 5.
3. move the stick to just above idle and press the button closest to the rotary switch (this sets the sync point to that position). I am also assuming that you have a newer version of the software as shipped from RCS and not one of the first field trial units (because early versions of SW did not have a programmable sync point).
4. Then move the throttle to full throttle and hit the button furthest away from the rotary switch. (This programs the full throttle position).
5. move selector switch back to position 0 and cycle power.

After this you should be able to follow the installation instructions with out problems.

Let me know if you need more help.

RE: Eletronic engine syncronizer **SUPPORT **
 

Might be good to update future manuals with that info.

I'll try to squeeze some time in during this week, and re-work my throttle linkages.
Thank-you for your help!

RE: Eletronic engine syncronizer **SUPPORT **
 

My TwinSync already has the connector for the display (next to the Red LED), and has the newer sw ver. 1.2.0. Would I still need to send mine back to you for mod's to use this remote display?

Reason I ask, is that RC Showcase now lists these displays.

RE: Eletronic engine syncronizer **SUPPORT **
 

No units have shipped yet enabled for the display (except one prototype in the field for testing). All units shipping after now will be display enabled. So yes even with the newer software you need to send the unit back to me because it needs a wiring change and a different software load to support the display.

The two pin connector on all Twinsyncs shipped before now are so that you can wire a remote led to indicate glow plug status (i.e. not to run the display).

RE: Eletronic engine syncronizer **SUPPORT **
 

Hi Bill,

I received the TWIN SYNC a few days ago. Nice fast shipping. Thanks.

Will the TWIN SYNC work if I'm using a five cell pack. I've not tried it yet, and didn't want to connect it unless I knew for sure it would be O.K.. What is the Vcc ABS MAX of the pic?

Also I could measure this but I was wondering how much current the syncronizer consumes.

I'm having some problems with interference and am in the process of debugging this problem. I've changed the receiver and a new (same ch.) crystal, but no luck so far. Still more work to do. I'm setting this up on a Seagull Dual Ace.

Thanks, Erik

RE: Eletronic engine syncronizer **SUPPORT **
 

Voltage is no issue... it will handle up to about 20Volts.

Let's stay in contact on the interference issue because I have seen problems on magneto equiped gas engines with rubber spark boots but never a problem on glow. Do you have a metal push rod connection to a metal throttle arm on the carb? Are you using the onboard glow? If so could vibration be causing a metal to metal contact vibration?

I am increasing the filtering on the device but almost all interfernce problems observed so far with > 50 units in the field have been due to sensor wires being attached to conductive mounts with the engines - a no-no - or with ignition engines. Regardless I think I about have this solved but most test people solved it without my involvement.

This will be the first report of glow interference.

Bill

RE: Eletronic engine syncronizer **SUPPORT **
 

Interference.....as in strange glitching of your throttle &/or rudder servo's???

Mine did that when I had the throttle end points less than 100% each way on my transmitter.
Very odd, as NOTHING was connected from TwinSync to my Rudder channel!
Modified my throttle linkages so I have 125% E.P.'s and so far - so good!

Friday/today I test run the engines with the TwinSync & do both range checks.
Then if all's well, Saturday will be the first airborne test!

RE: Eletronic engine syncronizer **SUPPORT **
 

As for power consumption of the device it really depends on how many LEDs are on - on average over time. The device pulls about 10ma with no LEDs lit. Each LED draws about 15ma. There are 5 leds (optional 6th for glow plug status). That means with all LEDS on total power consumption is still less than 100ma.

As for observed interference. The gas engine guys have seen erratic throttle servo movement when they were getting interference from the spark plug. This was limited only to the TwinSync and not in servos connected directly to the receiver. In some cases, it reduced the PCM lockout range of the twinsync (not the receiver) from about 75 yards to about 50 yards.

PS The reason you can run the Twinsync on any voltage is that it has on board regulation - i.e. not powered directly from the battery. This also helps isolate noise so that it doesn't get back to the receiver.

RE: Eletronic engine syncronizer **SUPPORT **
 

Bill,
Is there a LOW voltage limit for the TwinSync? I ask because while setting up a unit on my P-38 the battery voltage dropped. The servos kept responding slowly, but the TwinSync stopped accepting programming changes. All was well after charging the battery.

Drifter

RE: Eletronic engine syncronizer **SUPPORT **
 

Hi Bill and a1pcfixer, thanks for the quick response.

Interesting, I'm using aluminum stock 1/2" x 1/8" for the sensor mounts which are bolted to the engine. Sounds like I should change this first. The interference seems to be the worst when both engines are running.

Good news on the 4 vs 5 cell packs, I prefer 5 cells.

I use cable for the throttle with a nylon socket and metal ball on the carb connection.

I don't have batteries connected to the glow portion of the twin sync yet.

The radio is a Futaba 7CAP. I've set the end point throws in the radio for 125% and the cable to horn servo connection is very close to the center to compensate.

I would like to use the 3 position switch as CH7 to control the AUX but I'm not sure how to assign that "G" switch to CH7 in the transmitter. Any help would be appreciated.

Thanks, Erik

RE: Eletronic engine syncronizer **SUPPORT **
 

Low voltage limit on the twinsync is 3.8V for normal operation and the device shuts off at about 3.5V.

Do not use conductive sensor mounts (if so do not attach them to the engine) - double no-no

The rest of your install sounds fine.

I don't have a Futaba 7CAP. On a 9CAP it is the AUX-CH memu you use to program switches to channels. (that's a Futaba question not a TwinSync question)

RE: Eletronic engine syncronizer **SUPPORT **
 

Hey Erik,

Two demerits for you, and you get to stay after class to clean all the erasers & blackboards!:D

RE: Eletronic engine syncronizer **SUPPORT **
 

Ch7??? Don't you mean ch5? as in L.G. (gear).

[link=http://www.futaba-rc.com/faq/index.html]Futaba FAQ's[/link]

[link=http://www.futaba-rc.com/faq/faq-7c.html]7C Radio System FAQ[/link]

RE: Eletronic engine syncronizer **SUPPORT **
 

Thanks a1pcfixer, I actually found what I was looking for in the menu.... Just not intuitive. Thanks for the links though.

I made up new sensor mounts using 5-ply and the major interference seems to be gone. However, maybe a low battery has confused the twin sync. I need to go through each menu to confirm that each setting is what I expect. The first symptom is the responce time, both engines hunt for sync. They oscillate around the target and eventually get confused enough that one engine will quit.

I need more time to work on this. I've experimented with faster and slower loop speeds, but ended up putting it back to the default.

Thanks for the good support.

More to come, Erik

RE: Eletronic engine syncronizer **SUPPORT **
 

I might have your second report, or a bad TwinSync unit[&o]

On my TwinStar w/2 Evolution NT36's, the TwinSync isn't working correctly.
After startup, if I set throttle on Tx to above idle....say 1/2 throttle, the #2/right engine goes to that,
but the #1/left engine goes to 1/2 throttle then slowly closes. Very bizzare!

On board glow isn't giving enough juice to start engines. I'm running 2 Sanyo 1700 mAH in parallel,
and yes they were fully charged. I'll figure out this iisue, but the above issue needs your assistance.

RE: Eletronic engine syncronizer **SUPPORT **
 

Jim,

email me a day/time that you can talk and be at/work with the plane and email me your phone #. My email is [email protected]. I don't have enough info yet to determine what your problem is. If you can not have a discussion with me the next couple of days then go ahead and send the unit back and I will put it on the test bench. If you send it back I need no wires only the unit itself.

I suspect the following on the throttle control issue
1. Sensor install issue
2. RFI - glow plugs not working right adds to this suspicion.
3. problem with your device.

Two other things I can suggest if you want to try a couple of things right away.

1. Try it with the glow plug drivers disconnected.
2. swap sensor and throttle servo connections to see if the issue is with one channel on the device (i.e. other engine has problem) or the same engine still has the problem afterwards (interference or sensor issue with that engine).

Email me a close up picture of your sensor install and that might clear up the issue as well.

As for the glow plug issue measure the voltage on the plug, the battery, and coming out of the unit. The wires coming out of the unit are 60 strand 22 AWG. Most 22 AWG gauge has less than a dozen strand which will not reach very far. You should be getting the same voltage at the plug that is coming out of the TwinSync. If you are getting more than a couple of tenths of a volt drop through the twinsync then I need to look at it. I expect that the voltage drop is probably in your wiring.

Bill

RE: Eletronic engine syncronizer **SUPPORT **
 

Hi Bill,

I found a cold solder joint on one of the HALL effect sensors. It had broken inside the shrink wrap and was intermittent. Re-soldered this and it's trying to sync once again.

I'm using only one magnet per engine. I've set the AUX channel so I can independently run up each engine.

Still the loop compensation seems off.

Once I get both engines running, they will both sync up past 6 or 7K RPM or so. They really lock on up there. But below that both engines oscillate slowly around the target. Each will over shoot and under shoot at around 1Hz or so, maybe a bit slower. Then engines vary up and down at least 500 RPM.

The engines are O.S. 61 FX's spinning EVOLUTION 3-blade props. which I think is about 10x6. I know this is a little less prop than the engine needs but I'm expecting to only need to run up to around 5/8 full throttle. I know at full throttle the engines will excede the 11.?K upper limit.

I've experimented with faster and slower by a couple of steps, but haven't found one to make the loop stable.

I am planning on setting the TWIN SYNC on two Saito 56 on my bench to see if there is any change.

Any thoughts would be appreciated. Erik

RE: Eletronic engine syncronizer **SUPPORT **
 

First off, partly myself to blame....I had the engine sensor connections switched (#1 on #2 - #2 on #1)
Once I corrected that, the problem was reduced a bunch, but still there.

As per item #1 above, do you think my spacing as follows is part of the problem?
Sensor to magnet/prop back plate spacing;
Engine #1= .025
Engine #2= .041

1. done
2. switched channels as per your directions, and the problem then transferred to other engine.

I'm getting 1.41 volts at the battery, TwinSync, and glow plug tips.
I'll try a new set of glow plugs later this week.

I'l post them here, so others can take a peek too.
First photo has a toothpick pointing to gap at tip of sensor.
Sensors are zip-tied to a piece of plastic mounted on the engine bolts, then epoxied as well.

RE: Eletronic engine syncronizer **SUPPORT **
 

Jim,


Please re-desribe the problem you are seeing now. Initially you described some of the symptoms of sensor or interference problems. If you reverse the sensors it should move one engine to wot and close the other. Problems tend to fall into the following categories:
- No Sync
- Hunting or oscillation
- erratic throttle servo movement.

Please describe what you are seeing now. Clearances are fine. Any less than 0.2" should work.

If you have 1.4Volts at the plug you have a bad plug if it is not hot.

Bill

RE: Eletronic engine syncronizer **SUPPORT **
 

In response to the following:

Erik,

I just saw this post. I know exactly what you are talking about now.

Yes, there can be some low RPM hunting (or oscillating) as you describe below 7K RPM with one magnet (or even with two magnets in some cases) depending on your throttle geometry (i.e. 1% servo change results is ?x100 rpm change -- if ? is > 3 then you will see some hunting in that range) and I have duplicated and solved this.

I have been working with some of the guys testing this in the field and have had this reported and so I have newer software now that fixes this low RPM "hunting" but you may still need to adjust your mechanical linkage to ideally get about 200-300rpm/1deg servo movement. This is kind of like mechanical aileron differential where 1/2 throttle is at 4:30 on a clock dial rather than 3:00 for equal throw above and below mid stick. This gives you a lower rpm change per degree servo movement below 1/2 stick.

So I am working on a new 1.2X software release that will solve this and a few other specific engine/usage issues. I hope to modify the mode 4 programming to include some servo speed and sync range parameters in the next major software release rather than just response time as it does now.

I am currently shipping 1.2.1 software on new units that solve this issue. You can send me your chip or unit back and I think the latest software will git rid of this (depending on your mechanical setup). However, if you sending something back I would send the unit with the chip because there are a couple of other updates I would do to it (display support and increased filtering to match currently shipping units). Just include $5 for return shipping if you send back the entire unit.

Bill

RE: Eletronic engine syncronizer **SUPPORT **
 

One other comment for everyone:

Glow engines should have one magnet (i.e. > 11K RPM)

Gas engines should have two magnets (i.e. peak RPM < 11K)

Bill

RE: Eletronic engine syncronizer **SUPPORT **
 

Now, it moves one engine(#1) to WOT, the other engine(#2) goes to WOT then drops back to about 1/2 throttle. If I lower the throttle
on Tx a couple clicks from WOT, then the 1/2 throttle engine(#2) jumps back up to match the other(#1). I can hear the #2 engine
hunting for synch with #1 engine.

Well, it appears that engine #2 is not in sync with engine #1, and it seems to hunt for synch.

I'm still running with servo's/sensors switched on TwinSync. I'll put them back as they should be and re-test.

RE: Eletronic engine syncronizer **SUPPORT **
 

The device will not sync or work if the sensors are reversed. It actually becomes an ANTI-SYNC if you reverse the sensors/servos.

I would expect one engine to go to full throttle and the other to go to idle over time with things reversed.

ONLY CONNECT SENSOR1 TO THE ENGINE BEING CONTROLLED BY SERVO1 and vice versa.

RE: Eletronic engine syncronizer **SUPPORT **
 

Hi Bill,

The unit is on it's way back to you today (Monday). Please send me a unit with your current software.

Many thanks, Erik