P-Limited Motors - Im going to jump on the hot seat.

[Darin Jordan]

I've wrapped up the motor testing for now. Finished up by testing the SSS3660-1968 motor, and the SSS3660-1800 motor.

The SSS3660-1968 motor actually tested fine. Just a tick less power than the TP and Turnigy SK3.

However, the SSS3660-1800 motor burned up on the stand after about 50-seconds at only 94-Amps. Didn't fully self-destruct, but the windings show that they did get a little hot and must have shorted.

Not sure what to think of this, but it seems that with the SSS motors, when you try to load the lower KV motors up to the power levels of the higher KV stuff, they burn. Recall the same thing happened with the SSS3650-1500 motor (it looks VERY toasty inside!).

I decided not to even test the SSS3660-1500. Tired of my garage getting stunk up and frankly, I don't think it would fair much better. The 1968KV version, like I said, actually looked good. There are a couple different ways to get KV out of a motor, or to lower KV in a motor, and it's clear that the SSS motors seem to build resistance as the KV goes down.

Anyhow, here are the final data graphs and complete data chart for the tests. A couple of conclusions can be drawn, but the one that really stands out is that we actually did a REALLY good job of "equating" motors in P-LTD for the original motor set. They are all relatively close in power output potential, etc.

The second conclusion that might be drawn is that there simply aren't a lot, if any, "equivalent" replacements out there for these motors. You can either go UP in power, or down, but nothing really achieves an equal performance level. The one most obvious choice by many, at the given power levels, is 1620RPM higher, and there is still room to push that option.

I guess now it's time to discuss.

Here is the data.

SSS3660-1968:
Slide22_SSS3660_1968.jpg

SSS3660-1800:
Slide23_SSS3660_1800.jpg


DATA CHART:
Slide24_FINAL_CHART.jpg

[Darin Jordan]

A while back, this discussion got a little "heated" when people were suggesting motors like the Leopard 4074, or even allowing the new Dynamite 3930-1750 from the IM31 V3 (40x68 1750KV).

To help understand WHY allowing the larger, 40mm or ??? motor sizes into P-LTD cannot possible be done fairly, I ran two 60 second load tests on the Dynamite DYNM3930, one at the standard ~100A load (TRIED to get it right there, but ended up "only" being 97.00A... Close enough, but for you nit-pickers out there... sue me! ), and the other at 140A.


At 100A, you'll see that the temperature increase is over 30-degrees LESS than any of the P-LTD motors. KV drop is only 14%, the RPMs are about the same as an AQ2030, as is the power output of around 1500W (2.0HP, approximately). SO, Yes, you could run this motor with the same prop and, in theory, have about the same top speed, with cooler temps. You WOULD, however, enjoy the advantage of stronger acceleration, as the torque of the larger motor would spool up the load harder.

At 140A, well, that's the difference in a big motor. While the rest of the P-LTD motors are smoking in the infield, the 40mm motor is still only around 170-degrees (on the test bench with NO water cooling), pushing out over 2000 Watts, 2.75HP, according to the test run, or 3/4HP MORE than any of the P-LTD motors. I'm pretty sure if you ran 140A through any of the other P-LTD motors for 60-seconds, they'd end up smelly. Anyone who has pushed one beyond 100A for an extended period of time can attest. MIGHT get away with 115-125A for a few races, but eventually the motor is going to bake.

If you don't think that is a "performance advantage", well... I'm not sure we can have a rational discussion.

Here is the data from the larger motor test.

Pro Boat Dynamite DYNM3930-1750KV ~ 100A:
Slide25_DYNM3930_1750_100A.jpg

Pro Boat Dynamite DYNM3930-1750KV ~ 140A:
Slide26_DYNM3930_1750_140A.jpg

DYNM3930-1750KV DATA CHART:
Slide27_DYNM3930_DATA_CHART.jpg

[Darin Jordan]

I can imagine that a couple of the options would be to: 1) Do nothing, let the class run as is and die off once motors aren't available, 2) Accept that the existing motors are fading off, approve some quality options, and let the class "re-level" itself over a year or so (which has the con of negating the present investments of most competitors in the short term), or 3) Approve the smaller 3650-sized motors and slow the class down that level. Probably maximum of 80A, or 4)... well... Not sure if there is a 4.

Thought of a 4th option... Select a single motor, like some of the clubs across the Country have already done.

In lieu of having a viable motor or two to include, the only of these 4 options that actually maintains the class is to just leave it alone. The other options completely alter the present performance levels of the class.

[ray schrauwen]

Thanks Darin. I didn't get an answer for one question: Where did you get the AQ2030 motor from for your tests? I might want to check out the newest version for next season. For now I will keep beating up on the used one I bought a year or more ago.

Do you think the reason for the lack of 3rd party comparable motors is because the AQ and PB motors are 6 pole motors and the rest were 4 pole if I remember correctly??

[Darin Jordan]

Thanks Darin. I didn't get an answer for one question: Where did you get the AQ2030 motor from for your tests? I might want to check out the newest version for next season. For now I will keep beating up on the used one I bought a year or more ago.

I bought two motors from Steven about 1 1/2 years ago. This was one of those.

Do you think the reason for the lack of 3rd party comparable motors is because the AQ and PB motors are 6 pole motors and the rest were 4 pole if I remember correctly??

Probably. There is definitely a difference in motors of equal size, one being 4-pole and the other 6. I haven't sat down to try to quantify the difference, but I think we've all seen the difference when we went from 2-Pole Nemesis/Fiego motors to the Neus and such, so it's obviously a torque difference. It did appear that the 6-Poles could turn a similar load with less Amps.

[rayzerdesigns]

heres my thoughts or two cents as some say, im with darin as in leaving it as is with the 3 motors, yes the aquacraft motors are more expensive and in my eyes and darins testing the dynamite 1500 is 20 dollars cheaper and a better motor..again just my thoughts..i dont have a problem with clubs using a motor for club level the only thing is if you set your boats up with such motor, then have to change out if you decide to run a national event, or run for records, you have to change back..so my 2 cents is leave it until we start seeing a shortage of these 3 motors..

[T.S.Davis]

Too bad PB doesn't make the 1800 any more. I'm surprised how close in performance the PB and AQ 1800's are. Spooky.

The Turnigy and TP3660 are pretty close to each other too. Although both are a bit more motor than the existing list.

[Darin Jordan]

The Turnigy and TP3660 are pretty close to each other too. Although both are a bit more motor than the existing list.

I'd quantify it as a bit more than a "bit"... That Turnigy SK3 would be worth 5-6mph in a Hydro.

[rayzerdesigns]

I wish dynamite would bring 1800 back.. But in all honesty im comitted to the 1500s..

[T.S.Davis]

I'd quantify it as a bit more than a "bit"... That Turnigy SK3 would be worth 5-6mph in a Hydro.

I was trying not to kick the cage.

I use all three. Not everything Ty and run liked the same setups. His Delta for instance gets weird on larger props and I'm just not moving the strut on it again. The option is nice.

[Darin Jordan]

I wish dynamite would bring 1800 back..

Yeah, unfortunately that ship has sailed...

And, as you can see, the 2000 isn't the magic bullet.

[rayzerdesigns]

Im sure i will duprise some people at nats in 2016 eith the 1500s.. Opened a few eyes in colorado this year.. Lol

[Darin Jordan]

Im sure i will duprise some people at nats in 2016 eith the 1500s.. Opened a few eyes in colorado this year.. Lol

You forget that I "introduced" them to these motors first...

Those here locally have already been "indoctrinated"...

[ray schrauwen]

Im sure i will duprise some people at nats in 2016 eith the 1500s.. Opened a few eyes in colorado this year.. Lol

May I ask some advice on what prop to use for df33 used in both spec Sprint and spec offshore? Just a starting point so I don't wreck a motor too fast I'm running the AQ 1800 now with about an M447'ish for Sprint, m445'ish for offshore.

[rayzerdesigns]

May I ask some advice on what prop to use for df33 used in both spec Sprint and spec offshore? Just a starting point so I don't wreck a motor too fast I'm running the AQ 1800 now with about an M447'ish for Sprint, m445'ish for offshore.

For those motors or 1500s??