Frank Schwartz

My Feedback: (1)

Many, many years ago, at Toledo, I purchased a Glow Plug Driver kit from a fellow who was set up there. It has been the best glow driver I ever had, but the meter has gone out. Does anyone out there have one in their junk box, or parts of one that I might purchase?

I tried writing the the fellow who made them in Bridgeport CT, but my mail came back.

Thank you............

Avaiojet

Radio Shack? A standard item for electronic hobbiest.

fizzwater2

My Feedback: (61)

Frank - are there any markings on the meter you can see? Let me know or shoot me a good closeup picture, I'll try to help you find one.

Frank Schwartz

My Feedback: (1)

No Markings I can see...on the lower left of the meter face is "LM" on the right lower portion of the meter face is "watts"
That's it... I will try to attach a picture...

Frank Schwartz

My Feedback: (1)

One more thing: On the face of the Power Panel is: Northeast Engineering, P.O. Box 6201, Bridgeport, CT 06606. That sort of locates the source. Mail to him there came back. Not known....... Anyone from around there know this fellow or have any information???
Thank you..........

ClutchCargo

Frank -

Does the Plugdriver work without the meter? If so, I suggest you keep using it that way since finding a direct electrical and physical replacement will probably be difficult.

If the unit won't work without the meter, then it must be an ammeter (as opposed to a voltmeter). In that case you can just remove the meter and short together the two wires that went to it, and the box should start working again.

FYI the first Northeast Plugdrivers didn't have a meter - you just marked or remembered knob positions for each kind of plug you used. The company did not move, it went out of business, so you are unlikely to get any official help.

Clutch

Frank Schwartz

My Feedback: (1)

Well, it is not working now, but I will spruce it up and try it with the meter out of the circuit and then a jumper across where it was. I think it was used as an ammeter with a shorting shunt. I loved tha tunit and it would light a plug even under water...never failed to start an engine right off, flooded or not. Thanks for the heads up...I'll try it and get back and post results.
Frank

N1EDM

My Feedback: (2)

OTher places to look for meters are www.mouser.com and www.newark.com. Lots of meters, so you will have a lot of information to sift through. The site isn't set up for us hobbiests, it's set up for commercial businesses which makes it a bit more difficult to navigate, but you can find things there.

Just my $.02

Bob

ClutchCargo

Frank -

If there was a meter with a shunt across it, then it was actually a voltmeter, but together with the shunt was acting as an ammeter overall. In that case the box will work with only the shunt in place, as you are considering.

In fact it will theoretically work even better with a dead short in place of the shunt, but you may feel more comfortable keeping the shunt. The shunt introduces a voltage drop, probably either in the main supply (from the battery) or in the ouput leads going to the glowplug. However, the NE plugdriver inherently compensates for a wide range of losses including voltage drops in either of these lines. That's why it works so well e.g. the "plug under water" bit.

FYI, a schematic of the original Northeast Engineering plugdriver circuit can be found at:

http://www.freepatentsonline.com/us4130853.pdf

The op amp is an LM324. Imay be able to come up withpart numbers for the other semiconductors. The resistors, caps & diodes are generic.

This does not show the meter which was added later. Can you report where in the circuit the meter/shunt is connected?

Clutch

Frank Schwartz

My Feedback: (1)

WoW ! 1 ! You readlly did your homework! Tickled to death to get the diagram printed out. I suspected it was patented as the fellow I bought the kit from at Toledo told me so and after watching his demonstrations, there was no way I could not purchase one. It is the best I ever had, with one exception...but it still is/was the best. Sluggish engines started right up...always.
I will look on the circuit board and find out where the meter was placed and get back to this posting for it. Only need to now the type and values of the diodes and what F1 really was...well looking at the diagram I realized taht F1 was the glow plug
I can see what D1 and D8 are D2 - 7 are ones I am not sure of...possibly 1N1418 generic type??

Finally, the unit was so good, I am surprised someone didn't get the persmission or rights to continue to produce it.
The otehr one was a dc to dc convertor unit made by Sonictronics..of coourse no longer made...it works avery well and will put 1 1/2 volts on a plug regardless of the type or whether flooded or not....
Frank

ClutchCargo

The original patent was issued in 1978 so it expired long ago.  I suppose anyone could start making it.  All the parts it used are still standard electronic items.

I think one of the reasons why the Northeast Engineering plugdriver is no longer made is because people didn't understand how technically advanced it was over the competition.

If you look at the NE patent references you'll see that the most relevant is 4,002,882 by Charles W. McCutchen.  Mr. McCutchen was (and hopefully still is) a well-known physicist, inventor, and general contributor to science.  That electronics was not his field only increases his accomplishment in the original plugdriver circuit design.  Primarily, in getting his creation to work at all - because it is amazingly complicated and certainly not manufacturable.  You can see it at:

http://images.freepatentsonline.com/us4002882.pdf

Despite its deficiencies, McCutchen's circuit demonstrated the idea of sending a short pulse of power through a glow plug's filament, then measuring the filament temperature by sensing its resistance.  Based on the resistance, the next pulse of power would be made longer or shorter in duration.

This is why such a design is relatively insensitive to battery voltage drops, and quite insensitive to wiring losses, plug heat losses (e.g. underwater) etc.  If the plug is for any reason not hot enough, the plugdriver makes it hotter.  This is also why it is much better than a fixed voltage source (the next most simple circuit), and *much* better than a fixed current source (the simplest and worst circuit - a dropping resistor).

The Northeast Engineering plugdriver was a more professionally designed, manufacturable realization of what McCutchen had demonstrated.  It used fewer parts and was far more stable and reproducible.  It would keep a plug lit even with a power starter being driven by the same gel cell, in winter.

However, you certainly can't explain these things in a magazine ad, and nobody will read it if you do.  Even RC equipment reviewers may not understand what they're looking at or really test it thoroughly.  Unless you saw the Northeast plugdriver in action (as at Toledo) you would probably buy one of several "power panels" offered by the big names, figuring they're all about the same.  And they were the same... fixed voltage or current sources.  And in fact the fixed voltage sources might work well enough, most of the time.  Maybe your Sonictronics box shows that.

The Northeast Engineering plugdriver was essentially a boutique item, which you wouldn't value until you had used it, especially under difficult conditions.  I suspect the meter was added largely to make the device look more like the competition, and to just show the user what the glow plug already knew: that when it needed more power it would get it.

Clutch

Frank Schwartz

My Feedback: (1)

Well, I have examined the one I have with the Meter...and compared it to the diagram you referred me to that has the LED...and they are not the same... The LED could have been a substitute in the early diagram for the meter on the later model. I will have to look into this some more..
Oh the original patent, it was in 1977.
Yes, it was so good nobody reeally took it too seriously. I really want to get mine going agian and will play with it some more. It goes along with the saying that a "prophet is without honor in his own country" or something to that effect......and often a great item, in RC and many other areas for sure, is ignored for something that is far less as good. My own experience: I have an airfoil I used on my Q500's. It was developed for me by some air craft engineers at the Lockheed facility in Atlanta on their simulator late at night when nothing else was happening. The sent me the first and I built a plane with it and over six months I built seven models and we finally settled on an airfoil Each time I buklt one using each modification, they wanted to kow the trim setups and how it performed. It was very clean and fast..it had low drag and when put in a positive attitude (roll on its side and pull up to turn around the pylon) the lift went up tremendoously and the drag stayed low. While other planes skidded through the the turns, mine would actually accelerate. Now when I was in competition...like about ten years or so ago...and in my seventies, I placed seventh in a field of 200 at the Nationals. If I had known how to tweak an engine or fly better, I could have swept the field as my plane was fast, fast, fast and turned quicker. I begged some of the hot shots to try it and nobody would listen to me...they were happy with an airfoil that was traced from the side of their shoe or "it looks good to me". In truth my airfoil is the only one I know of that was actually designed for a model airplane...the enginiers who did the planninig for it told me that if I had hired Lockheeds computer simulators to do the work, which they did at night for fun, it would have cost at least 300K dollars for the time! A year or two ago I gave the parameters to a friend locally who makes laser cut kits and he designed a scale racer for a fellow using that same airfoil I gave him and they said it was the fastest they ever flew and turned quicker as well...but nobody wants to use my airfoil...and I just gave up... the idea of a better mouse trap and people are happy with what they have...OK...I am off the soap box now...and, too, at 85 I don't have the reflexes I had nor the eyesight I had ten years ago so my racing days are over....
Frank

Frank Schwartz

My Feedback: (1)

Back to the power panel. I checked the circuitry vs the one that was the original patent and it is far from the same. This one works even without the meter and uses a 555, a coouple of transisters and diodes and so on. Have to be careful adjusting the level as it will blow a glow plug like a flash bulb, but turned down, seems to work very well...still need a diagram and a meter...I wonder if anyone has a diagram for this later version???
Frank Schwartz

ClutchCargo

Frank -

From your description, I wonder if the Northeast Engineering power panel you have is based on this circuit (schematic attached).

This design dates from 1976 and is known as the "Sunday Driver". It is much simpler than the original NE Plugdriver and does not directly control plug filament temperature. However, it does compensate for battery droop and that indirectly provides some regulation of the filament. The design has inherent short circuit protection primarily because of its limited regulation capability. The value of the 3.3K resistor is adjusted for plug brightness so in practice it would be something like a 5K pot instead.

Considering how few parts there are, the Sunday Driver accomplishes a lot and is *much* better than any passive circuit or even a linear regulator.

If you can trace yours out and comment on any differences, I'd be interested in the details.

Clutch

Frank Schwartz

My Feedback: (1)

Thanks for the diagram...the meter circuit on mine is unusual and as soon as I can find time to sit down and trace out the board, I will post the diagram. It does use the 555 timer and the two transistors, but some of the values are somewhat different from your diagram....Oddly, I have drawn up the meter circuit, but cannot figure out how it works...it has me baffled.....but am still working on the diagram...will get it out on this thread asap...
Frank Schwartz

summerwind

hi guys,
i realize this is an old thread, but after a long long search i finally found one of these fantastic drivers.
had one 20 years ago and like a dumb dumb, let it go cuz i had quit flying.
the one i have is the led style. the glow plug lead is intact with a connector for the glow plug.
what the seller did not do though was label the power leads.
how can i determine which lead goes to the + and - battery posts?

ClutchCargo

Summerwind -

The most direct and basic testrequires anohmmeter. Look at the first page of the patent at this link:



http://www.freepatentsonline.com/us4130853.pdf

This is a schematic of the box you have. F1 is the filament of your glow plug. You can see that one side of it is directly connected electrically to the battery negative terminal. The metal glow plug connectors were "Dubro" products. The shell is the negative (ground) side.

So: with no glow plug in the connector, usean ohmmeter on its lowest resistance scale tosee which battery lead is a direct short to the outer shell of the Dubro connector. That's the negative battery lead.

Also notice in the schematic that the lead coming from the positive battery terminal has a diode / rectifier in each path it feeds.This means that even if you connect the box up backwards to the battery, you won't hurt it. So you can just try the battery leads both ways and see which one works. But I recommend the simple test above first.

Good luck!

Clutch

summerwind

thx Clutch,

i did poke around with the ohm meter.........and memory from high school electronics tells me that too........just want to be sure.
i left modeling 20 years ago and made a foolish move in selling all my gear. been looking for one of these for a year now. finally got one. here are a couple shots of the face and inside.

summerwind

OK, i have labeled what i think is correct with a red + and -................look right?

Frank Schwartz

My Feedback: (1)

That's it !!
FrankHowever, with the safety diode in the circuit, it is impossible to hook it up wrong. If the 12 volt leads are incoorrectly connected the unit just won't work. Correctly, it will...
Frank

summerwind

thx guys!

i hook 'er up.

-mike

summerwind

works great!!

amazing that no one has continued to make this driver.
for our purpose, this driver is invaluable.
Free Flight competition requires fire in the head as soon as a thermal comes thru.

this link is of some stuff i have posted here on RCU.

http://www.rcuniverse.com/forum/m_10787547/tm.htm

the model at the bottom is powered by an OPS 65 speed running 50% nitro fuel. head clearance set to unload in the air, but is finicky with not enough heat to the Globee plug.
the Northeast driver was and still is the answer to cold engines that are fed with high pressure bladder systems.

many thx to you Frank for posting this thread, and to Clutch for explaining things.

-mike

JohnBuckner

My Feedback: (1)

Summerwind please forgive me for the off subject question. Are you a Sams member and do you participate in any of their events, As I suspect you are and do I have a couple of questions for you about their events.

John[8D]

summerwind

hi John,
no i haven't joined Sams yet again.
ask away though.
if i don't know the answer, i know many who will

-mike

JohnBuckner

My Feedback: (1)

Hey thanks Mike I joined Sams back in January at the big Ontario AMA show having never been involved before although I started modeling in 54 with controlline and added RC a bit later, pretty much never really stopped. Anyway They said at the time the next event planned for the El Dorado dry lake near Las Vegas was to be in 2013 and I hope to participate if my ships will fit into some catagory (eighty inch Playboy RC with a modern .35 glow and a Kerswap with a modern diesel)

I do get the Sams Speaks but no mention of it yet. By the way I enjoyed the lovely pictures of your free flight adventures.

John