what controller to buy

[dretceterini]

The stuff I have is 35 year old crap, so what should I buy for 1/32nd SCALE racing, and the Marconi proxy race in particular. I DON'T want to spend a lot of money on a "modern" electric controller..

Thanks,
Stu

[Green Destiny]

You could try a Professor Motor controller-they start around $49.95 Professor Motor Website (http://www.professormotor.com) for more information. They are really good about replying to inquiries. Glenn

[RollinI]

I swear I'm not looking to get flamed, but....

I don't think you need a controller for a "proxy" race.

Unless of course, you're one of the designated drivers. And if you are, then my apologies.

[dretceterini]

Thye have so much available, I'm not sure exactly which one to get...so I e-mailed them for a suggestion..

Stu

[oldweirdherald]

35 year old "crap"???

Hey - for 1/32 scale racing, the 35 year old stuff is sometimes what's best!

I still have and use a 35 year old Parma controller, but my favorite one for 1/32's is a new Parma Turbo with a dual ohm setup and switch, as per Weird Jack Stinson's article here at OWH.

Weird Jack's Dual Ohm Parma Article (http://www.oldweirdherald.com/scalestuff/onethreetwo/controller/controller.html)


I also have and use a Proffesor Motor controller, and a few Ruddocks. It's all a matter of what you feel you need and how much you want to spend.

BTW - the above reply is correct, however, regarding the Proxy race. If you mail in your car, you don't need a controller. The controllers will be a spec controller fixed to the track. If you want to "dial in" your car for the race, you should do your dialing with the same model and ohm controller that will be used at the Proxy Race. Check out the Marconi Proxy web site, and/or get in touch with Phillipe (who is currently in Europe for a while) regarding what controller will be used.

[LoudCat]

If you are sending in a proxy car you should test it with the kind of controller that the proxy drivers are going to be using. I watched the race last year and I can tell you that many cars were almost undriveable because the builder failed to take into account the controller type.

I think last year the proxy race used a very inexpensive 75 ohm resistor controller.

[dretceterini]

I have a REAL old Russkit that is like an early Parma, but it needs rebuilding. I have a 40 year old MRRC blue THUMB PLUNGER type...the 1st verson with a wire on the to for static brakes.

I don't want to spend a lot of money...the Parma Turbo sounds pretty good, but how much is it? Is the ohm switch standard, or did Jack install it?

75 Ohm at Marconi? I would think they would use something more like 45 Ohm, but what do I know...I've been "away" for 30 years..

Stu

[Larry Geddes]

Controllers must be 45 ohm.

For 1/32 use, a Parma Sebring is plenty good enough, especially since you won't be running cobalt straps with it. Buy 3 or 4 & put a different resistor in each. Plafit Cheetahs are great with a 15!

[oldweirdherald]

Did you READ Jack's article? It tells exactly what parts to use and how to install the extra resistor and switch on a Parma controller.

Jack shows the math and did his conversion on a Parma Sebring controller. Parma Sebring's are around $20.

The Parma Turbo is around $40, but they are rugged, smooth, have bigger wires, etc., and are a much better long term investment in my opinion.

The photos and captions at the bottom of Jack's article show my Parma Turbo, converted for 1/32 and HO use. I used a Parma 45 ohm resistor, with a 10 ohm resistor and switch from Radio Shack added on, giving it a 25 ohm option which is great for Fly and other strong magnet cars. The switch I used on that one kept breaking, though, so on my 2nd one I'm using a heavier toggle switch - located on the front, where there's more room.

That's the cheapest and most versatile solution I know of. The next step up is a Professor Motor controller for $50. If you didn't mind spending a bit more, I'd wait a bit for the release of the new Parma Turbo E.C. Electronic Controller. The prototypes we used at the recent Parma Challenge Cup worked great.

But - if Parma 45 ohm controllers is what will be used at the Marconi Proxy race (which I do believe is correct), then that is all you really need if your intention is merely to tune your cars for that race.

[GearBear]

Hey Stu,

If I'm correct that old Ruskit is the same as the Parma Sebring. So go over to Weird Jacks site and do the mod for the dual resistor. Your local track should be able to set you up with a new resistor that will fit it too! A dual resistor set up will be nice to have if you are running 1/32nd cars! Some will like the 25 and some the 45!

[dretceterini]

I just am FAR too busy to do the conversion!

Stu

[pbj59]

What is the range ( ohms ) on the new Parma electronic controller? I've never used an electronic controller but I heard it doesnt take much to destroy them, even having a clip come off and touch the wrong place, or connecting one wrong. Is the Parma unit more durable? What motors can you use it on? I'm considering a new controller purchase and might wait till these come out.

[Prof Fate]

I dont still have my old Stromie blue trigger controller with the speed band on it that went to 200 MPH., but I do have most of the others I have purchased over the years. Several Cox controllers, several MRRCs including a vari power. My first 15 ohm Blue Russkit.
In the last year on all tracks with everything from scaley to Gp. 15 I have used only my entry level PM.
Well, sort of, when I check out a car for the Marconi, I use a spec 45ohm Sebring.

Fate

[dretceterini]

It looks like I will be buying a new controller in the next few days..

Stu

:D

[oldweirdherald]

Parma has not announced a ship date for their new Parma Turbo E.C. controller yet - but it should be fairly soon. They had printed flyers about it at the Challenge Cup, and we put a bunch of them through a pretty darned good test session all weekend long.

The Turbo E.C. has a fuse in it, that sticks out the side for quick replacement, that should protect most wiring mishaps. I don't know the equivelant ohm rating, but I believe they mentioned that it can be used for HO's through most (or all) 1/24 classes.

Paul C. preadjusted all of the Challenge Cup controllers, then cut off the adjustment knobs to prevent anyone from monkeying with them, so I didn't get a chance to play with one before they were "neutered", but I believe Paul will be bringing one with him this weekend to the AFTW's, and if so, I'll check it out more.

If the new controller works for such a wide range, along with the adjustability and smooth operation, then the one-time bigger price tag may be well worth the wait and the investment.

[Larry Geddes]

Paul ----- I checked out the article you mentioned. It does indeed look like an effective, cheap way to have some added flexibility. As a further improvement, I would leave the switch out & run the wires to a socket dangling out the bottom of the handle. That way, you could have any number of resistors that would just "plug & play". You would no longer be able to change resistance during the race, but it could easily be done between heats.

The circuit is not a simple parallel resistor deal, though. The usual formula, RT = R1 x R2 / R1 + R2 applies only to fixed resistors, & has to be modified to describe what is really going on. One of the resistors (the stock "internal" resistor) is acting as a voltage divider, since current will flow through the portion of the resistor behind the wiper button AND the portion ahead of it (unlike the normal controller wiring, where ONLY the portion of the resistor AHEAD of the wiper button sees current). As the trigger is pulled further back, extra resistance is added IN SERIES to the "external" resistor, changing its value.

This makes for some radical differences in the response curve (trigger position VS total resistance) depending on the values chosen for the two resistors. For example, with your 45 & 10 ohm combination, you should have 8.18 ohms when the wiper button just touches the windings. At 1/4 trigger pull you should have 13.04 ohms, at 1/2 trigger 13.30 ohms, & at 3/4 trigger 8.94 ohms. It appears that your curve has a hump in the middle :p . If you get a chance, check this out with an ohmmeter & let me know what you get.

I'm going to do some more math with a variety of different internal & external resistors to see what the curves look like. This seems like a pretty good controller idea for home track racers & deserves a closer look.

[GearBear]

Originally posted by Larry Geddes
Paul ----- I checked out the article you mentioned. It does indeed look like an effective, cheap way to have some added flexibility. As a further improvement, I would leave the switch out & run the wires to a socket dangling out the bottom of the handle. That way, you could have any number of resistors that would just "plug & play". You would no longer be able to change resistance during the race, but it could easily be done between heats.


why not use a brake pot for a difalco or ruddock instead of the fixed resistor? You would then have something almost as good as an electronic controller (Adjustable sensitivity) but at a much lower price!

[Larry Geddes]

Why didn't I think of that? :p Good idea. It would have to have way more resistance than a brake rheostat (typically 2 to 5 ohms) but not as much as a potentiometer. An electronic supply site should be able to supply a (let's say) 50 ohm 25 watt rheostat that should work.

It would have to have an "off" position, or an on-off switch could be added, because if the resistance is dialed down to 0 ohms, there is effectively a jumper across the ends of the resistor. The car would be at max speed at BOTH ends of the trigger stroke & at min speed at half trigger.

I think there's a lot of possibilities with this idea.

[Larry Geddes]

I've done a little more research on the idea of having two resistors in parallel, one variable (the normal controller resistor) & one fixed (the one added for the modification). As was pointed out, a rheostat could be used instead of a number of interchangeable fixed resistors, but at this stage I'd like to stick to resistors of known value for the sake of calculation.

I've plotted some graphs for 3 different combinations of resistors, one where the variable (or internal) resistor (R1) is much larger than the fixed (or external) resistor (R2), one where R1 & R2 are equal, & one where R1 is smaller than R2. The graphs show total resistance VS trigger (or wiper button) position. In all cases the curve is a parabola, but the difference is that its location relative to the trigger position varies, depending on the resistors chosen.

In the first case (R1>R2) the trigger (hence the wiper button) at the very start, when the button touches the first winding, is quite far down the left side of the parabola. As the trigger is pulled back, resistance INCREASES until the button reaches the apex of the parabola, then drops as it travels down the right side. As is noted, this is actually Paul Kassens' controller.

In the second case, R1=R2, the start position of the wiper button is just about at the very top of the curve, & descends smoothly from there.

The third case shows R1<R2, & the button is already below the apex at the start, leaving a more rapid descent.

For all three examples, I chose 45 ohms as R1, just for consistency. I have also plotted other resistor combinations, but do not have them ready to post.

The thing about the trigger curve is that the response is flatter near the low-speed end (at least for the second & third examples) which may make it easier for some racers in the twistier areas of the track, & it is steeper at the high-speed end, which makes for more rapid response.

Before anyone suggests buying an electronic controller instead, let me say A) any controller can be modified this way for a few bucks, & B) it's FUN! :D

[Larry Geddes]

Here's the second one -

[Larry Geddes]

And the third -