I've got a friend who has just about finished a 120" ish twin with Saito 56s. All up weight around 16 pounds.

Anyway he has decided to go with onboard glow drivers from Electro Dynamics. He is thinking for installing the batteries in the nacelles and the driver units in the fuse near the receiver. This will require a 28 inch lead from the battery to the driver unit and then back out to the glow plug. Of course a circuit on each side. For those who have done on board glow on a twin, do you think this would work?

I've suggested he skip the glow driver units and just wire them direct with a swithc in the nacelle and then have them off or on manually. He doesn't have enough room around the servo in the nacelle to work in some sort of a micro swithc use the throttle movement.

THanks for any input you can offer.

CHris

Chris,
Here is the info you need....

Inexpensive and reliable onboard glow system.

Here is a system that I have been using for a few years now. I tried some of the manufactured glow systems and found them lacking. I was told by one manufacture when I called with questions that if I had a big enough battery his would make it glow the whole flight. So I said I can do that myself and save about $40-$50.
This system is very reliable. It does not burn up glow plugs. I get about 40 minutes of continues glow with one charge. The engines have a very quick response. I have used this system on my Satio 150 inverted, 2-OS 91's inverted, Magnum 61's. All parts are available at your local Radio Shack. I have included a couple of pic's and a diagram of the set up. I have $12.00 in the whole set up minus the glow plug connector.( which you have to buy with whatever system you buy). The $12 does include battery which a bought system does not.

You Need:
part # 274-1569 Size M Coaxial DC Power Plug....... For charge Jack $2.49 2 pack
274-1563 Size M Panel Mount DC power Jack..... $1.99
275-634 SPST ToggleSwitch $2.99
C size Battery Holder $.99
Rechargeable 2000mah C Battery $7.49 2 pack


This is all you need to make the onboard glow set up. I do use 18 or 20 Gauge wire for this. I solder the heavier wire to the battery holder also. You have to have a solder gun to do this because it has to be done fast not to melt the plastic. ( just like the heavier wire) I have my 3 engine Sovia Marchetti S79 set up with 3 of these. It adds only 4 oz to the plane, each. The set up fits easily in an engine compartment. The battery holder has holes so it can be screwed to the firewall or engine mount. I have one complete set in each of the nacelles. I just turn them on at the beginning of each flight and leave it on.


Here are pic's of the parts.
A diagram of the set up .
The Nacelle of my S 79 with the charge jack and switch.

Ty

I have had over 20 flights on the S79 without an engine cutting off.....

Fuzzy pic inside the cowl.....

Ty

Chris:

I installed Ty's set up in my Tri-Motor a couple of months ago..It works great on the bench..haven't flown it yet...not finished with it...hopefully next month, after my operation for a cataract on my eye...Wasn't hard to set up and am using Hobbico Quik Field Charger MK ll to charge the single cells....Try it..I think you'll like it

Ty and Jimmy,

This info is great...

thanks

Chris

The electrodynamics system is well-made and works very nicely. It is very easy to program on/off from the radio. But as stated above it is not needed if you plan to run the glow full-time.

Not running the glow full-time has one major advantage- more flights before recharging. The glow plugs will pull the battery down pretty fast.

The standard electrodynamics "twin" system uses only one battery for both glow plugs, I'm not sure how you would rig it up with two but I'm sure it is possible.

It shouldn't matter where all the pieces to the glow system are mounted, but whatever system is used, be sure to use heavy wire especially if you have long runs.

Warning about using a micro switch for on board glow control. I had one plane with it and the radio would twitch or flutter when the contacts closed or opened. Others have not seen this, but I did. Install a capacitor to kill the spark worked.
One problem with only one driver and a parallel connection. The two glow plugs never have the same resisitance and it changes when one engine starts. The result is that one glow plug either does not light or is too dim to help. This means two drivers. Or, if the glow driver will allow it, go to 3volts and wire the engines in series, not parallel.
Good Luck,
Twinman

Pardon my ignorance, but how is this setup used? If it is turned on all the time, does it serve to prevent engine shutoffs? What is its purpose if it is turned on and off from the radio, independent of the former purpose?

Just curious, that's all.

Scubyfan-

The reason for using on-board glow is to keep the plugs "hot" during low RPM/idle, which should help engine reliability. With the controller you can program it so that the glow is energized only during idle conditions, which saves battery time and is in theory easier on the glow plugs.

I don't have onboard glow on my Twin-Air because my OS 46's are plenty reliable at idle and the plane is supposed to be relatively easy to handle on one motor. But I did install onboard glow on my Mustang's twin-cylinder Saito to prevent a cylinder from dropping out at low RPM.

By the way, the standard electrodynamics twin setup uses a 3V battery wired in series through the glow plugs as Bill describes. The controller is designed to handle this.

I have been using this set up for years without any problems. No clitches ever experienced by me. There is no spark with this system to cause interference during flight. With the set up I have described here you must use 1 battery per glow plug. I have tried it on 2 and you can get them both to glow. I even use 4 2000mah batteries in parallel and it would not make both glow.
This system is very basic. I don't fly for 40 minutes straight. That is how long you get with a fully charged 2000mah battery. I just use it for realiable engine runs. With my 3 engine Savoia the 2 outboard engines pull of of one center tank and the fuel flow is always changing. The rpms may vary 200- 300 RPMs at any one time. So I run these engines rich. The glow on all the time just makes sure the rich mixture does not cut off the engine.
If you see the need to spend the money on a of the shelf item, more power to you. I just don't see paying $40-$60 for something I can do for $12.....

I also use the Hobbico Quik Field Charger MK ll to top offf the batteries after a couple flights and it works great......


Ty