Understanding FE power VS IC

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HTV Boats

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3AM you wake up to "P" and your mind goes WTF

Anyway I hope we can open up and share some ideas and viewpoints on "power" how it's determined and how it relates to boat racing classification.

This is my conception and not gospel by any means so feel free to jump in anywhere.
Internal combustion falls in two categories, glow fuel Nitro and spark ignition naturally aspirated Gas. Class structure is done with Cu. In. limitations. (.20-.40-.60 and up & 27-36)
Letters and numbers different in IMPBA and NAMBA but very similar limits.
Only limit on Nitro is size without certain fuel additives. Gas uses size pump gas and from what I see NAMBA is piston port and IMPBA allows 2 & 4 stroke.
Cubic inches are maximum using variations of bore and stroke. Naturally aspirated means no blowers or turbos. Compression not specified or port configuration other than NAMBA gas piston port. Power is brake HP and torque affected by engine internals.
( I guess Don Huff is working out a turbo nitro motor but that's another discussion)

So now how does the motor sports world and model boats define electric power classification? You lead with Voltage and restrict with length limits where applicable. Two motors no problem, wait not in IMPBA "P". No consideration for size (other than hull length) You can run a 40X100+mm motor in NPQS&T. Power is watts and you get more watts with motor size than just increasing voltage. Manufacturers rate power in watts and it sure looks to me that larger dimensions make more power. A 40X92mm motor has more power potential than a 36X74mm can size. Much like a 350 Chevy can make more power with cam and carbs electric motors have different rotor and wire configurations that make more power. Yes a smaller size motor can make more power in wattage but like cubes there is a limit.
So do we consider a total rework of FE classification? "What if" you use volts and size. Without designations consider these limits
36X60mm - 4S single motor
40X82mm - 4S single motor
40X74mm - 6S single motor
40X110mm -6S single motor
Unlimited class no motor size limit & twin power allowed 6S-10S, total weight under 24lbs wet,
5 power options and then hull variations Cat Mono Hydro OB Tunnel Sport Hydro and Scale. Hydro 1/10 1/6 1/8th??
Twin Cats 4-6S? 36 & 40mm?
Archive records and start over.
Ok flame suit on.
Mic

Much of motorsports uses cu. in. as the base classification then restricts fuel and intake to level things. Not sure how Formula E cars regulate maybe someone will chime in.
 

RaceMechaniX

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Comparing ICE's with FE's is a fruitless discussion for our hobby. If we want parity in a FE class we need to implement an electronic power limiter. This is a simple device placed in between the ESC and battery and interrupts the ESC signal from the receiver. A shunt measures current and voltage tap measures voltage, multiply to get a power. You can choose whether it has a hard cut off or start's pulsing the output. Similar devices exist for pylon racing, but would need some modification for boats. Neu Motors sells an energy limiter for F3E pylon racing which is close and probably could be modified in software to work. Are we all willing to pay $75 per limiter? If we want parity in performance the answer should be "yes".

Allow any new model boater to run without a limiter for club racing or fun runs and clubs can police when limiters are needed. For large races, Nationals and record trials a limiter is required and visually teched for tampering.

I am 100% against changing any other class besides P-ltd. Putting length and diameter limits in the other classes nullifies 90% of the FE boats I run.
 

HTV Boats

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OK the power limiter is not really available and needs modification. How do we tech it? Will there be different current limits in P,Q,S and T? Some car classes have a blinky light on the ESC which I understand may blink and not limit. Do we need a $75 (est) unit for each boat we run or does it adapt to several hulls. Would it not be easier to limit battery capacity?
I understand length and diameter would change a lot of existing boats. I also don't think purpose of racing is parity. Innovation drives most racer I know. We all want an edge and it has to be somewhere without shooting fish in a barrel.
I appreciate your knowledge Tyler though we are not on the same page. I personally would welcome a reliable limiter but not sure many will pony up the extra.
Mic
 

HTV Boats

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Could you not achieve the desired result with limiting the esc rating?
The issue with ESC become manufacturers specs and over rating. Make a dedicated ESC list and we find better cheaper options we can't use while the ones on the list aren't made anymore. Tylers current limiter is a better option.
Mic
 

LohringMiller

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I keep saying that an easy way to limit current is to limit prop diameter. Power absorbed changes as the FIFTH power of diameter. A very small diameter change results in a big power change. At a fixed voltage that limits power. Pitch has a much smaller effect. This rule has been tested in electric 1/8 scale racing. Below is a graph from my P limited rigger. I'll run a different prop next race and compare the result.

Lohring Miller

P spec 6-2021.jpg
 

RaceMechaniX

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Why do we need to change Q, S and T? If I proposed changing all of the outboard classes you would be equally frustrated. Let's stick with limiting this discussion to P-Ltd.

An electronic limiter is not far off. We would just need to ask Neu to modify the software to replace the Watt-min to a Watt limiter. The limiters are supposed to be tamper proof, but I agree there are ways of potentially cheating.

Do we want a low cost entry level class or do we want a power parity class where setup and driver skill are emphasized? A low cost entry level class is only needed for club level racing. Clubs have classes for stock UL-1's, stock Motley Crue's, SV27's and so on. That's great for introducing and getting new boaters hooked and further involved. A "spec" class with an electronic limiter would be closest to emphasizing setup, skill and driving and allow maximum freedom to run different power systems so long as they all are choked by the same device.

Limiting battery capacity is a weak argument just like limiting ESC current to a nameplate rating. I can put anything I want on a sticker. To tech battery capacity we would need to charge and discharge a pack. Who wants to do this? Also do you allow larger capacities for offshore?

Using battery mass is a better metric to tech since it's also easy with a scale.

The greatest downside I have seen with battery mass or capacity limits are people will run the batteries down to the ragged edge and beyond. Now you burn down boats and open a large safety issue which I am sure both IMPBA and NAMBA would like to avoid.
 
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HTV Boats

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I don't know what you could do to tunnels to kill them. Kinda self fulfilled prophecy. I understand wholesale changes and have Q and T equipment. S is not run anywhere other than records. Actually S in my mind would be better than Q as I have a ton of 4S packs to run in series/parallel. easier on the ESC than Q.
From what I see around the country Q and larger boats exist but don't gather in numbers. I have 2 large hydro's and other than records no where to compete. Last local race I signed up in Q mono to make the 3 boats and one dropped. 6 local Q/lim tunnels started the race. I guess I am looking at what it takes to get numbers on the water over a few elite boats. Besides causing trouble and rebel rousing I spend a bit of time promoting and holding FE events. I hope I am giving more than I am taking for myself.
Mic
 
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HTV Boats

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Before I take a needed nap I want to address battery limit. It is in the Namba book with no criteria for inspection other than sticker value. Not good.
I though about a way to enforce an energy limit and weight though not perfect makes the most sense to me. Right now I see P/L run with 5000-10000ma. 5000 was kind of the norm but then 6600 and I could come in with cells above 3.8v easily. Then prop up and go to 10000. OOps motor smoke. Well if you over push performance this will happen. I have seen a lot of puffed cells but the fires I have witnessed came from CHARGING. Back to burn down. If you haven't carefully pushed limits in a setup and seen smoke you probably don't see many podiums.
Asking a racer to pull his batteries to weigh them is no where near asking him to remove a motor to tech. That and battery safety says you should not charge them in the hull.
So now is weight perfect. No but easily enforced and does limit heat race speed. It also allows record setups where they belong, that won't make 6 heat laps. For the sake of argument rather than even use a MA # I threw the dart at 600grams for P/L I looked at numerous brands and found most all quality brands were around 5000-6000ma. Some low C over 7000ma combinations exist but I would not run them. Example Roaring Top 4S batts.
70c 5000ma 523 grams
70c 5500ma 563 grams
70c 3300ma X 2 - 6600ma 358g X 2 =716 grams
35c 3300ma X 2 6600ma 288g X 2 = 576 grams
3 choices under 600g here.
I have 45c 5000ma packs in parallel that are 2-3mph slower than my 5000ma 70c pack. Not a double blind study so look at what you use and some other brands and see what you would put in your boat with an arbitrary 600g limit. Add 10g grace so you don't need to de solder connectors.
If anything maybe we will conclude roads that should not be traveled in this discussion, pros and cons.
Mic
 

T.S.Davis

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We tried the RTR thing like Tyler suggested. Eliminates the "something for everyone" factor. Vets get bored and quit running them. Then you have a new guy show up wanting to get started. He buys the RTR and there are no heats for him.

Mic, I'm not being obtuse but you aren't thinking that a complete revamp is necessary or more importantly possible are you? IMPBA can't/wont respond to what it's membership is actually doing let alone a complete flush of all the FE classes with a replacement. You have a better chance of curing cancer my friend.

Even if you could work out the limiters..........you would need a decade+ of data.........apparently. Maybe if it was a gas class you could run a year trial just based on an idea but not FE. Doesn't work that way for us. Plus a single manufacturer providing limiters? That always works out.

The battery weight thing becomes - replace the shrink, shorten the wires, lighten up on connectors, ditch any velcro. I could see guys soldering connectors right to the tabs with no wire and maybe kapton tape.

Hey, that reminds me. I'm fire protection engineer. Can anyone explain to me how batteries charged in an open top vessel that I can grab with my bare hands and throw is less safe than charging them on a plastic table right next to that same vessel? One of those hmmmmm things that has puzzled me for some time. Doesn't matter I guess. Do what yer told mister.
 

RaceMechaniX

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The only time I have seen capacity limits become a challenge was in NAMBA racing for 4 min timed offshore. P-Ltd was the only class where 10,000mAh was enough to make 4 min with the same setup for heat racing since the motor was the limited to around 90-100A before it would cook. Every other class including N2 needed every mAh to finish the 4 min race. Puffed batteries were almost guaranteed if you were competitive. Fortunately we don't run 4 min timed offshore races but once in a blue moon.

NAVIGA used battery mass limits for the a period of time and as Terry described guys were removing shrink, connectors were directly soldered to tabs and bare minimum insulation. They found a 35C battery with the highest energy density was the best balance, but they burned quite a few batteries. They are now testing a similar energy limiter to what is being using in pylon racing. Everyone uses a standardized 6mm connector so limiters can be exchanged if disputed and they are building a simple LED system to check after a race if the energy limit was exceeded.

I for one use multiple sets of batteries per boat for a race weekend so I am not fast charging a recently run set and potentially damaging the cells or worse catching fire. There is plenty of opportunity to run a cheater pack in some rounds where I am less likely to be teched.

I do think FE can shelf N-stock, N2 and S and keep P, Q and T.
 

Mike Hughes

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Thank god I dont run electric. Too much to keep track of...............oh wait.......I have 1/10 scale. oooooopsy. LOL I will let you guys figure it out.
Mike

PS I remember the OG days of brushed nicad set ups. GOOD TIMES
 

kyleboyer

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It never fails. There is always someone out there, who feels the need, to regulate you. "Hey! She can't do that! Shoot her or something!"----Nute Gunray
 
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Christian Lucas

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Hi,
there are allways two way . The better is to use a limiter like Tyler say, i have the limiter form steve Neu and test it with the pylon limits . No problem to use them right out the box and to have a fun racing event.
The other is only to limit the batterie pack waight , number of cell and cappasiti 1P is enough no need of switching twin pack parallel.
From NAVIGA i know that some competitor from eastern staate charge the batteries to a higher voltage. every 0,1 Volt offers higher cappasity that count when running the finals. To prevent the pack to explode they put the pack inside a steel or carbon case. Hey, do you want a spezial safty garde at ebery event ? i think no.
And Lohring the newer motordesigns can do a lot moore than today motors . We can switch the number of pole during operation , reduce the loss in all magnet parts rise efficancy , so the powerlevel will by high at every part or full load operation. See the new small dia Lehner outrunner that can easy handle 500 Amps at 15 Volt at 94% efficancy . This motor turn a Octura 2267 at 24000 rpm 7500 watt or 5,5 horses. You know Jörg Mirkwitschka and his spezial made batteries . So currently many batteriy manufakturys develop low resitance batteries as they use them for breaking recovery in cars , i know this from Bosch having such batteries and other car companys do this like VW and BMW .

Happy Amps Christian
 

HTV Boats

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Racers are always going to push rules to the limits and that is part of why we all do this. I have no delusions on a total revamp just opening up a thought process of what might work. Here's what I see so far
Even though people will try to reduced battery weight it still puts a limit to energy available. So you find a pack that's 800ma higher and shave off 30grams to make it pass you still only have only gained a slight edge that time spent with a prop might have given more.
Props don't come in many pitch variations at any given diameter and would inhibit performance on some hulls. A certain style like scale can get away with it but you might need several diameters and blade area for the variations from tunnel cat mono and various hydro's. I am not a fan of prop restriction as I feel they are critical to setup.
Motor dimensions (at least in P) seem to be somewhat accepted vs removing and weighing one.
Limiters have and do work but add expense and hardware that can create more issues. Again do we need different limits in every class or is this just a P/L solution. Then what is the chosen limit, will it take 10 years to argue and decide amps 80 90 95 100 105? Then does the chosen limit affect motor selection. Is it cost effective and incumbent to growth. Do we all need new motors.
In the above so far and you had to choose what would be easiest to implement and tech after the race what would be your 1st choice. 2nd?
'N classes are not run enough even in records so they don't affect much. S & T could be combined easily rather than drop S. Call it U class and that has a natural unlimited ring rather than open. If you look at records S & T are a toss up and there are 8S controllers that work less amps than Q. That and the multitude of 4S packs in most racers inventory make it an easy step up class.
A plastic table is not a good charge surface or is strapped in a boat. But with the lack of incidents so far (knock on wood) we are growing lax on safely charging not in a fire proof container. Add inside a trailer and the best practices are not followed. It will take a serious injury to wake us all up there. I am guilty as anyone here. If anything comes out of this tread maybe this will make it a positive step.
Mic
 

jevmax

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Feb 12, 2004
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231
3AM you wake up to "P" and your mind goes WTF

Anyway I hope we can open up and share some ideas and viewpoints on "power" how it's determined and how it relates to boat racing classification.

This is my conception and not gospel by any means so feel free to jump in anywhere.
Internal combustion falls in two categories, glow fuel Nitro and spark ignition naturally aspirated Gas. Class structure is done with Cu. In. limitations. (.20-.40-.60 and up & 27-36)
Letters and numbers different in IMPBA and NAMBA but very similar limits.
Only limit on Nitro is size without certain fuel additives. Gas uses size pump gas and from what I see NAMBA is piston port and IMPBA allows 2 & 4 stroke.
Cubic inches are maximum using variations of bore and stroke. Naturally aspirated means no blowers or turbos. Compression not specified or port configuration other than NAMBA gas piston port. Power is brake HP and torque affected by engine internals.
( I guess Don Huff is working out a turbo nitro motor but that's another discussion)

So now how does the motor sports world and model boats define electric power classification? You lead with Voltage and restrict with length limits where applicable. Two motors no problem, wait not in IMPBA "P". No consideration for size (other than hull length) You can run a 40X100+mm motor in NPQS&T. Power is watts and you get more watts with motor size than just increasing voltage. Manufacturers rate power in watts and it sure looks to me that larger dimensions make more power. A 40X92mm motor has more power potential than a 36X74mm can size. Much like a 350 Chevy can make more power with cam and carbs electric motors have different rotor and wire configurations that make more power. Yes a smaller size motor can make more power in wattage but like cubes there is a limit.
So do we consider a total rework of FE classification? "What if" you use volts and size. Without designations consider these limits
36X60mm - 4S single motor
40X82mm - 4S single motor
40X74mm - 6S single motor
40X110mm -6S single motor
Unlimited class no motor size limit & twin power allowed 6S-10S, total weight under 24lbs wet,
5 power options and then hull variations Cat Mono Hydro OB Tunnel Sport Hydro and Scale. Hydro 1/10 1/6 1/8th??
Twin Cats 4-6S? 36 & 40mm?
Archive records and start over.
Ok flame suit on.
Mic

Much of motorsports uses cu. in. as the base classification then restricts fuel and intake to level things. Not sure how Formula E cars regulate maybe someone will chime in.
I don’t understand the motivation for changing any of the rules pertaining to FE. I have never agreed with nor understood the rationale behind having length limits in each NAMBA class, but having no length limits in the nitro or gas classes.
 

Mike Yount

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FE Rules.jpg

I don’t believe it would be a total revamp of the rules. The change puts the restrictions where it belongs, the motor, not the hull length.

This is how I think the rules should look like. Note: The actual motor sizes I pulled out of thin air. They would need to be adjusted

Twins would add both motors together for total motor volume. Also it doesn’t matter if there’s a new smart motor or what. If it fits in the total volume it’s good. It’s kind of funny how the volume of a diameter and length is similar to bore and stroke……. or is it? I’m against mixing nitro and electric, but the simplicity and popularity of nitro is for a reason. Heck the motor volume could be specified in volume (ex: 3.75 in cubed, 5 in cubed, and so on…) No difference, that way people could experiment with different diameter to length ratios.

As always RTR classes should always be fostered and encouraged, just at the club level.
 
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