P Limited Hydro IMPBA.

[RaceMechaniX]

Kv is relatively easy to check, but not a good metric to limit performance. Rewound motors can have similar KV, but higher outputs. It also benefits higher pole count motors over lower pole count motors if KV limits are put in place.

 

[Mark Bullard]

I think I know a guy who has an electric motor shop and could probably start building some nice motors with a little encouragement............
He might need to buy a new rotor balancer though as the one he has may be a touch too big.

That's a good one Tyler. LOL You know I do not like playing on what I work on every day.
But I do have a book here by my old friend Luther "Red" Norris that is called "Servo Motor Basics Handbook". I will try and scan it and post a copy here. He wrote the book on servo testing and repair. And there is a lot of good information in it. Understand that all servo motors are brushless DC motors except the true DC motors. The only difference is that most servo motors have some sort of feedback device for commutation tracking. One other thing is the ESC use DC to power them but try and match AC on there output to make the three phase motor run. If you learn this book and understand it you may be as smart as me. LOL And if you do understand it and can use the information I may give you a job.

 

[RaceMechaniX]

Mark,
If I came to work for you productivity would plummet on work that brings in money. We would shoot the breeze over motor projects that never would bring in money, I would likely need to fire up your 12V149 daily to get my 2-stroke engine fix and we will probably be spending way too much time on building SST riggers.

If that all sounds acceptable send me a job application.

-Tyler

 

[Mark Bullard]

Mark,
If I came to work for you productivity would plummet on work that brings in money. We would shoot the breeze over motor projects that never would bring in money, I would likely need to fire up your 12V149 daily to get my 2-stroke engine fix and we will probably be spending way too much time on building SST riggers.

If that all sounds acceptable send me a job application.

-Tyler

Lot of truth in that statement. LOL

 

[Mike Yount]

I believe the P-limited issue is an evolving story exposing the fundamentals of electric classes.

In the beginning, voltage alone worked good for making classes.

Now after many years and evolving (battery/motor/ESC) it’s becomes clear more than voltage is needed to define electric classes. This is why P/limited is so popular currently. It's the addition of motor can size with voltage that creates parity for racing. The standard classes are too open. It’s like putting a 60 motor in a 20 boat.

The can size limit captures all motor variables possible and confines it to a physical size. So no matter who does what, (copper, iron, magnets, insulation, slots, # poles, air gap, winds, skew, etc.) the cream will always rise to the top. Racers will always find the best way.

It was inevitable can size limits would start spilling outside of P. The Q-limited class is now gaining popularity. This should become more popular than P because the boats are larger and the higher voltage makes the watts equation friendlier.

- Keep the classes down to the basic classes. Don’t add more classes.

- Remove the”current allowed motors” column and replace with can size limit for every class.

- Eliminate the hull length restriction for Mono/Catamaran & OB Tunnel. Keep all other length restrictions.

Absolutely RTR classes should always be available and encouraged to sustain the hobby. It’s been proven (SV27, UL-1, UL-19, Miss Vegas, etc.). Due to the ever changing landscape of products, keep this at a club level.

 

[T.S.Davis]

So you think that by using cheap wire will change the output torque of the motor? It is the size of the wire that changes the output torque of the motor. Plus the power of the magnets on the rotor. Check it with a torque wrench like I explained in an earlier post. This is the only true way of testing these motors.

It doesn't change the torque it changes watts out before failure.

If the enamel on one motors wind fails at 135 degrees and the other fails at 300 degrees then one motor has higher output potential. Another way to look at it......if you run both motors at the same output for an extended period at maybe 132 degrees the life span of the motor with the cheaper low temp wire will won't match the motor with the higher temp wire. Instead of having a motor fail mid season guys are running multiple seasons with no real performance hit.

Sam, checking the Kv on site doesn't really do anything. Two side by side motors could turn the same kv but one has high temp wire and more of it in the stator. Potential watts out are higher for the motor that can withstand higher temps and has 10% more copper.

Remember guys it still has to be simple. We can't expect everybody to be an electrical engineer. Length x width is pretty easy to tech. Rocket surgery? Now that I think about it.......is there an easier power level to tech in gas or nitro? I'm so ignorant. No tear down. No disassembly. Voltage-length-width......done. On to the hull.

 

[HTV Boats]

Remember guys it still has to be simple. We can't expect everybody to be an electrical engineer. Length x width is pretty easy to tech. Rocket surgery? Now that I think about it.......is there an easier power level to tech in gas or nitro? I'm so ignorant. No tear down. No disassembly. Voltage-length-width......done. On to the hull.

Yes there are some complicated ways to make a perfect system. However there is a simple system in place that is working and growing numbers. (36X60)
I look at many race flyers from IMPBA clubs that offer limited P classes. Not all are clear as to what exact motors are allowed. This is where a national standard structure would be nice.
On the other hand FE racers seem to have little real input. How many district directors have hands on FE experience? Or do they rely on a few who have knowledge to make decisions and don't want to be bothered with a newer form of power.
Mic

 

[Wasted wages]

Does the IMPBA not have a FE national director? Seems like the best thing would be to have a FE national director and district or regional directors that have a vested interest in FE and set set of FE rules and rulebook..

Just thinking out loud here !!

 

[Samuel Hagan JR]

Does the IMPBA not have a FE national director? Seems like the best thing would be to have a FE national director and district or regional directors that have a vested interest in FE and set set of FE rules and rulebook..

Just thinking out loud here !!

Yes we do. Mike Ball is the FE Director for IMPBA and has posted in the thread. I’m gonna give my District Director a rule proposal. Brad Maglinger is all about promoting the hobby and increasing people. It’ll pretty much what most people on here has said. A standard motor rule on the dimensions posted here and let’s see how it goes from there. Same as Namba. Motor and Volt rule. Hopefully the BOD will pass it so we can move on. And if we need to make changes in the future we can. I’ll have it to My Director by the end of the month.

 

[T.S.Davis]

Hopefully the BOD will pass it so we can move on. And if we need to make changes in the future we can. I’ll have it to My Director by the end of the month.

Best of luck. I thought about proposing it every cycle but making it no longer my problem was better for me personally. Maybe if it's not from me it will be better received but I doubt it.

 

[Wasted wages]

At least it would be a start !
It may not be perfect, but we need to start somewhere... Put it out to the people to vote on, and revisit and revise in a year if needed...

I don't see the big deal !!

 

[Samuel Hagan JR]

Maybe a 1 year trial.

 

[Grimracer]

I suspect most of the good ideas are on paper now.. I bet with that most of the "grey" areas in the rules have been "considered" .

People in the know have this "Close".. ZERO CHANCE you are going to make everybody happy ANYWAY... so...

IMPBA BOD.. get something in the books please.

Grim

 

[T.S.Davis]

I bet with that most of the "grey" areas in the rules have been "considered" .

That's just it Mike. Length x width. Took all the grey out completely. It couldn't be any easier to verify just two dimensions.

It's much like a 34" mono is a 34" mono. Compare a Huff Orca to a carbon fiber Raider or one of Oxidean's mono hulls. Entirely different beasts. All competitive under the right circumstances. All legal because there they're under 34". All the imagination we can stuff inside 34" is legal. How about a hand crafted one off Wildthing with ultra light stringers and 1/32" skins? Yep, did that. Not everyone has the ability to weasel the cutter into making the kit for them or the knowledge to build the flimsy bugger straight and square. Still a 34" mono. Still legal. How is that different than Don Huff tearing open a motor and learning what makes it tic........ then improving on it? Is he still within 36x60?

All this hand wringing about parity and fairness........it's racing. We can't legislate creativity out of racing. The better mouse trap is racing.

 

[Doug Smock]

A lot of talk about "easy". Voltage and length. (and scale for the big boys) It doesn't get any easier. Follow the rules on the books and stop beating your head against the keyboard...

 

[T.S.Davis]

A lot of talk about "easy". Voltage and length. (and scale for the big boys) It doesn't get any easier. Follow the rules on the books and stop beating your head against the keyboard...

Yep. Got it. Ignore what the racers want and what they have asked for. Go with what the BOD will allow.
Never let the racers decide for themselves. Hold the line!!!

Anybody getting it yet?

 

[HTV Boats]

If you are an IMPBA card holder and race FE please contact your district director and make him aware of your position. Ask him what percentage of boats in his (or her) district are running FE limited or existing rule book classes. Numbers count and will prevail. From what I see in entries P/L seem to be 50-70% of FE raced and yet not officially recognized.
Mic

 

[T.S.Davis]

From what I see in entries P/L seem to be 50-70% of FE raced and yet not officially recognized.
Mic

That's been true for well over a decade. In fairness, it's always been recognized.....just not by the IMPBA rule book.

I've not been to an event (NAMBA or IMPBA running NAMBA rules) that didn't have multiple limited classes since 2008. Prior to 2008 back to maybe 2003 or so the most popular classes were LSH and LSO Those classes were............wait for it..........limited........ to 700 brushed motors.

 

[T.S.Davis]

limited........ to 700 brushed motors.

By the way, there was a LOT LOT LOT of arguing about limited sport hydro and limited sport offshore motors when we were running brushed 700 motors.

Where we screwed those rules up was stating exactly which motors were legal by brand and model numbers. This should sound familiar since we made the exact same mistake in 2009 when we stated exactly which brand and model numbers were legal. Difference being that the 2009 motors were brushless. Then we had to add and subtract every time a motor vanished or appeared to be similar. We're slow learners.

 

[Grimracer]

I have to ponder.. maybe.. just maybe "limited" has run its course and we just move on to "P"?

Right now.. today.. how does "limited" help gain racers that "P" would not.

In limited.. now.. today.. what is the intent?
Then
What does the "limited" in limited mean?
IS
it now just an "add on class"?
IS
it now.. a records chasing class?

Open question...

Grim