Sullivan Dynatron

[Espeefan]

I have a quick question for those who own the Sullivan Dynatron stater. I just recieved mine, and thought I'd try it out. I was under the impression that this starter was pretty much the best a guy could get. I was expecting a lot more torque out of it then it had. I hooked it up to a good 12 volt car battery and I was able to grab the starter cone with my hand and stall the motor out. It didn't take nearly as much effort, to stall it, as I was expecting. Now I know that you don't want it to act like a cordless drill or anything, especially if your engine gets hydraulic lock (flooded condition), but I really was expecting more. Is it really not that much better then other starters, or do I just have a dud? Can you guys stall your starters out like this too? Just wondering.

[FlyJ]

Mine seems to work great. I don't think you will find a started that will turn your engine once its been fluid locked. at that point you'll either have to open up your plug and shoot it out, or buy one of the monster starters those guys use on the formula one planes and giant scale engines. I run mine with two 7 cell nicad's and it seems to spin any glow engine.

[WayneBrown]

consider that the starter will work from 12 to 24 volts, it's not surprising that you can stall it at 12v. I use a 5S1P flightpower battery on mine, and I assure you will not stall it.

[Espeefan]

Thanks guys. I just was curious to see what was normal.

Wayne, so with your LiPo pack, that's what, 16.5 volts? I was thinking I'd run 12-14 NiMh cells, so about 14.4 to 16.8 volts.

[WayneBrown]

If you can salvage batteries you already have, go that route, I did.
16v sounds about right, hell I never looked. :)
I know others have used it when theirs would not work and it spun the poo outta the engine. It's usually the most used starter at the field when I show up.
One tip though, if you want to use the century or maverick starter wand You will need to re-tap the hub to 1/4-28 as this is the only starter on the market with imperial threads.
I green locktited mine on, and with the rare hydrolock it stays put, although its putzed out a couple times by backing off the threads.

[Espeefan]

Got it Wayne. Yes, I have 6 cell packs laying around from my RC monster trucks, so I intend to use them. I do have a Century starter shaft, but it's not threaded at all. It's a compression type fit, with a hub and two pinch bolts. I was thinking I'd just get the proper Sullivan starter shaft, unless I can tap the Century to fit. I would have to size it up.

[WayneBrown]

I've had the sullivan shafts, and honestly you would be better with a string and stick....
(wrap the string around the shaft, tug on the stick...)
The Miniature Aircraft starter/battery kit makes a nice addition to the starter. The century or maverick wands are about $20 or so, and with a two minute tap job, work very well and you can remove the wand itself and make it a bit more compact.
You can also try two gel cell batteries in series for 24v, they work well also.
:)

[Espeefan]

Thanks Wayne. Is there a link you could provide me, with the MA starter battery kit? I have some K&S battery holders, but they are not specificall designed for the Dynatron. I can make my own mounting brackets however.

[Skiddz]

I run mine off a 6S LiPo and it's got a LOT of grunt..

I'll have to try one of those wands. The one I got kinda sucks...

[WayneBrown]

http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA4688
shows out of stock at Ron's, not shown on the MA site for some reason...

[Espeefan]

Thanks Wayne, again. Yeah, that looks like a nice battery mount. I'll have to search a few other sites and see if I can find a set in stock. Otherwise, that's very similar to what I had in mind for making my own. One way or another, I'll get it figured out.

[kcasser]

If you're still out there, how many mAh's do you have in your 5S1P? I've been using a 3S from my TRex 450, 2200 mAh, and it works on my Evo 50, but I'd like more power, less size. The setup sometimes has a hard time cranking it, and I've just read that it's not a good idea to keep trying if the starter won't turn the engine - something about catching fire or blowing up.

[Skiddz]

FWIW that battery mount is back in stock at Lund's - just ordered myself one.

[WayneBrown]

3850 MaH if I remember correctly. It's stowed in the camper and I've been bouncing from higher ground to more higher ground the past two days. :)
Indiana sucks this year.

[Espeefan]

Cool that those are back in stock, but I'm working on my own battery mounts right now. So far they are looking pretty good. I don't have much left to do on them. If they get done sometime soon, I'll snap some pics and share them.

[kcasser]

Them is expensive batteries! I only need to start a 50 Hyper, and would like to find something safer and cheaper than the 3S LiPo, but smaller than the 2 x 6 cell NiMH. Maybe I need to wait a few years.:roll:

[WayneBrown]

If you have a Dynatron, look into a 4A gel cell pack, 1 should do fine, 2 in series will start anything you want. Fairly inexpensive too, about $12/pack.
Another option is to look at less premium packs. I'd suggest the Outrage packs if you have extra cash, or you can look at www.batteriesamerica.com for lesser C rated cheapo's.

[kcasser]

Thanks, Wayne, but those 4A gel cells are weighty, aren't they? If I'm looking at them correctly, they're over 2 lbs a piece. I have the Dynatron and the MA bracket, and want to go wireless, so that sounds too heavy. For the LiPo's, the Outrage I saw that was closest to my price range was a 4S1P - 1800 mAh at about $65, but is 1800 mAh strong enough? I don't mind spending something, but anything north of $65-$70 seems a bit overkill to me when I can get two 6 cell nicds for $27. My hesitation with the nicds is just the bulk of their size. I might just stick with my TRex pack for now and see if I blow it up.:lol:

[WayneBrown]

If you have more than one well used Rex pack, I'd run them parallel to double the Mah and have at it.
I don't know the weight of the 4A, I know the 7A are pretty heavy..

[kcasser]

These are the things I don't yet understand. Is it better to run parallel and double the mAh, or series and double the volts? Would it follow that double the volts would make it spin faster but double the mAh would give it more torque?

[WayneBrown]

pretty much dead on.
You won't want to go over 24V or the starter will not last long.
By increasing the MaH rating, you get more grunt, which you need for starting the stubborn, wet engine. RPM alone won't spin one, you need torque.

[kcasser]

Thanks, Wayne! I'm going to order a 4S1P, 2100 mAh, 18C from FMA Direct when they get back in stock. I think that should cover me. Even with my 3S1P, 2170, everyone at the field is borrowing my starter and it works fine, so the 4S should be just a little better.

[Espeefan]

Here's another quick question. Like most DC motors, I noticed the Dynatron runs better when spinning clockwise, which unfortunately, is the wrong direction for starting engines. Has anyone noticed this and attempted to adjust the timing (or position of the brushes) of the motor to compensate? I don't know if it will be a big deal, but it feels stronger when running clockwise.