The Electric Class Structure

[forresterace]

AN OVERVIEW OF ELECTRIC CLASS STRUCTURE

Letters of the alphabet are used to indicate the maximum number of cells allowed in the class. Each letter is spaced in 6 cell increments over the previous class.

M - 4 cells

N - 6 cells (actually this means 5-6 cells since the use of only 4 cells would not be allowed)

O - 8 cells (7-8 cells)

P - 12 cells (9-12 cells)

Q - 18 cells (13-18 cells)

S - 24 cells (19-24 cells)

T - 32 cells (25-32 cells)

I'm not sure why the use of R was skipped.

In 4 cell and 6 cell classes, the use of the number 1 or 2 after the letter indicates the classification of Stock or open motor legality. Number 1 means Stock Motor Please note that this means the Roar Stock ferrite magnet car type motor only using bushings (no ball bearings). The number 2 designation indicates Open motor any type, bearings and magnets.

e.g. N1 - 6 cell stock motor

N2 - 6 cell Open motor

M1 - 4 cell stock motor

M2 - 4 cell Open motor

All other cell count classes ( O, P, Q, S, & T) are Open motor classes. The only exception is the Spec Motor class - LSH (Limited Sport Hydro). This is a 12 cell sport hydro class using a standard spec Motor (700 size)

After the cell count letter (and any motor designator) comes the hull type description.

Mono (the same definition as nitro classes)

Hydro (usually riggers but also any hydro, mono or cat hull)

Sport Hydro (same designation as nitro)

Offshore (Deep Vee Monos and Cats - stepped hulls are allowed)

NOTE :

These cell count classes are based on current cell chemistry available (Nicad and Nimh) which have a nominal cell voltage of 1.2 volts per cell. Very soon, the class structure is going to have to be changed to specify maximum voltage rather than the max number of cells. This is due to the coming new cell technology of Lithium Polymer cells (LiPo or LiPoly) which have a nominal cell voltage of 3.7 volts per cell. I think that their widespread use in boat racing is still a couple of years away due to limitations in discharge rate and high cost. These factors are changing very rapidly, however.

 

[Kevin Whitehead]

Doug,

That is not nearly as confusing as it could be.

Let me mix it up a little bit.

M Classes are 1-4 cells

N Classes are 1-6 cells

Yes, there is some overlap.

T Class goes up to 32 cells

R was likely skipped because of the potential of it being confused as P when read (just a guess) ;D

These are the NAMBA rules. IMPBA may vary a bit.

KW

 

[brooks93]

Doug good info

one thing though a stepped hull can run in hydro class's a also

 

[Grimracer]

Doug and gang

I took one look at the post and knew that #1 its looked like way to much information and #2 there is no way im going to grasp that info regarding me making the step to FE racing.

Information overload.

I think its nuts for both nitro, gas and FE that we have to use a letter descriptor and then qualify that with a real description. Why do we not just simplify the description? I mean for the FE dude that has been in it for sometime this is not a problem but just go to the LHS and ask for a mono that can run in the N class and I bet you get a big HUH? Not picking on the FE dudes as be have the same problem B Tunnel..what is that?..

I think that we leave it because "its always been that way"... Crazy if you ask me. Unless you are from the old school of Free Flight most have no idea where the letter descriptors cam from..

Sorry boaters but we need a CHANGE…Oooo that six letter word..lol

Grim ;D

 

[Paul Pachmayer]

Hey Guys,

I would agree with Mike, the letters to someone on the outside looking in is confusing. Took me some time to sort it all out when I first started in FE. Now it seems simple but in the begining :-

What's worse is trying to figure IMPBA FE classes, YIKES!

Personally I would still like to see a FE only Org. but......

Paul.

 

[forresterace]

OK Guys

We're agreed that letters don't relate to class specifications whether it's IC displacement or number of cells/voltage, but you have to have some descriptor.

This is the perfect time to have a good look where electric power (battery) technology is going and for once look ahead instead of working like crazy to maintain the status quo , otherwise we definitely going to get caught with our pants down ???

Soon battery technology (chemistry) is going to make using the number of cells to describe maximum pack voltage impossible to tech. Who know what cell chemistry is coming down the pipe right after LiPoly cells and what their nominal cell voltage will be. There seems to be a small grudging agreement that we are going to have to use maximum pack voltage as the class designator but there has been next to no discussion of how that could be implimented and how it will affect our class structure. There seems to be absolutely no movement within NAMBA to initiate this change before it becomes a disaster.

There are lots of points to consider before proposing a change so it's time we racers got talking about it. If we are going to change class specs, we should make sure that this proposal covers more than just the next level in cell chemistry (LiPoly) and cover all possible developments for a significant period of time. No sense in having to change it again in 2-3 years. Let's look ahead as far as we can and try to allow for all possible advances.

I don't think there is any question that pack voltage will continue to be the best measurable quantifier of battery pack performance. Remember, the key word here is measurable. Up until now, we have used nominal cell voltage (1.2 volts per cell) as the standard measure. We were lucky the this was the same for Nimh cells as it was for Nicad ones. LiPoly cells have a nominal cell voltage of 3.7 volts. What do you suppose future cell types will be? Another big problem here that I see is, just how useful (and measurable) is Nominal Cell (or pack) Voltage. How would you go about teching a boat for pack legality? A fully discharged cell (under no load) will read nominal cell voltage. How practical is that to tech on raceday?

A fully charged cell (off the charger) will read a higher than nominal cell voltage. I think that Nicad and Nimh packs will generally stabilize around 1.45 volts per cell fully charged and I have read that LiPoly cells, fully charged are about 4.23 volts. Perhaps Steve Hill could shed some more light on these numbers. This pack max voltage could be relatively easily measured prior to a heat race and if the correct values were chosen, could be valid as class designators for quite some time to come no matter what battery technology.

This might also be a perfect opportunity to have a serious look at the number of voltage classes that we have with the idea, perhaps, of reducing the numbers some by combining voltages. I have some further ideas in this direction but first I'd like to get your opinions and observations so far.

Comments.....

 

[Grimracer]

Can voltage be regulated by the ESC?

If so you might be able to use this to manage voltage. Maybe you could say 12 volt hydro? I know its not this easy but you get the idea.

You could then just check the ESC to see if its the RC Hydros (Hi Andy) 12V special (mythical) ESC..

You do know that i have no idea what the heck im taking about and am most likely talking out my ..... but if i can click a switch on someone else...

Grim

 

[Kevin Whitehead]

If you try to use controllers to limit voltage to the motor, the problem is just moved from batteries to controller.

Controllers can be modified by knowledgeable people and some are even now capable of having their operating parameters changed in seconds, via computer interface.

Also, controllers are generally usable over a range of classes (i.e. 6-12 cells or 6-24 cells), to place upper limits on them would immediately render all (or most) ESCs out there obsolete. It would also raise the cost of racing by requiring a specific controller for each class.

If some part of the sytem is to be specified, it should be the lowest cost part of the system.

In the future, specifying batteries (as motors have been done in LSH class) may be the only way to insure that everyone is close to equal.

With the ever-changing battery technology that is likely in the future, spec'ing a particular type of battery (right down to brand and model number) and periodically reviewing (and revising if necessary) the spec'd type, may be the only way that competition can be preserved.

KW

 

[sjslhill]

IMPBA:

L - 4 cells

The rest are the same except for motor differences.

AN OVERVIEW OF ELECTRIC CLASS STRUCTURE

Letters of the alphabet are used to indicate the maximum number of cells allowed in the class. Each letter is spaced in 6 cell increments over the previous class.

M - 4 cells

N - 6 cells (actually this means 5-6 cells since the use of only 4 cells would not be allowed)

O - 8 cells (7-8 cells)

P - 12 cells (9-12 cells)

Q - 18 cells (13-18 cells)

S - 24 cells (19-24 cells)

T - 32 cells (25-32 cells)

I'm not sure why the use of R was skipped.

In 4 cell and 6 cell classes, the use of the number 1 or 2 after the letter indicates the classification of Stock or open motor legality. Number 1 means Stock Motor Please note that this means the Roar Stock ferrite magnet car type motor only using bushings (no ball bearings). The number 2 designation indicates Open motor any type, bearings and magnets.

e.g. N1 - 6 cell stock motor

N2 - 6 cell Open motor

M1 - 4 cell stock motor

M2 - 4 cell Open motor

All other cell count classes ( O, P, Q, S, & T) are Open motor classes. The only exception is the Spec Motor class - LSH (Limited Sport Hydro). This is a 12 cell sport hydro class using a standard spec Motor (700 size)

After the cell count letter (and any motor designator) comes the hull type description.

Mono (the same definition as nitro classes)

Hydro (usually riggers but also any hydro, mono or cat hull)

Sport Hydro (same designation as nitro)

Offshore (Deep Vee Monos and Cats - stepped hulls are allowed)

NOTE :

These cell count classes are based on current cell chemistry available (Nicad and Nimh) which have a nominal cell voltage of 1.2 volts per cell. Very soon, the class structure is going to have to be changed to specify maximum voltage rather than the max number of cells. This is due to the coming new cell technology of Lithium Polymer cells (LiPo or LiPoly) which have a nominal cell voltage of 3.7 volts per cell. I think that their widespread use in boat racing is still a couple of years away due to limitations in discharge rate and high cost. These factors are changing very rapidly, however.

 

[sjslhill]

"A fully charged cell (off the charger) will read a higher than nominal cell voltage. I think that Nicad and Nimh packs will generally stabilize around 1.45 volts per cell fully charged and I have read that LiPoly cells, fully charged are about 4.23 volts. Perhaps Steve Hill could shed some more light on these numbers. This pack max voltage could be relatively easily measured prior to a heat race and if the correct values were chosen, could be valid as class designators for quite some time to come no matter what battery technology."

This is exactly correct.

OK Guys

We're agreed that letters don't relate to class specifications whether it's IC displacement or number of cells/voltage, but you have to have some descriptor.

This is the perfect time to have a good look where electric power (battery) technology is going and for once look ahead instead of working like crazy to maintain the status quo , otherwise we definitely going to get caught with our pants down ???

Soon battery technology (chemistry) is going to make using the number of cells to describe maximum pack voltage impossible to tech. Who know what cell chemistry is coming down the pipe right after LiPoly cells and what their nominal cell voltage will be. There seems to be a small grudging agreement that we are going to have to use maximum pack voltage as the class designator but there has been next to no discussion of how that could be implimented and how it will affect our class structure. There seems to be absolutely no movement within NAMBA to initiate this change before it becomes a disaster.

There are lots of points to consider before proposing a change so it's time we racers got talking about it. If we are going to change class specs, we should make sure that this proposal covers more than just the next level in cell chemistry (LiPoly) and cover all possible developments for a significant period of time. No sense in having to change it again in 2-3 years. Let's look ahead as far as we can and try to allow for all possible advances.

I don't think there is any question that pack voltage will continue to be the best measurable quantifier of battery pack performance. Remember, the key word here is measurable. Up until now, we have used nominal cell voltage (1.2 volts per cell) as the standard measure. We were lucky the this was the same for Nimh cells as it was for Nicad ones. LiPoly cells have a nominal cell voltage of 3.7 volts. What do you suppose future cell types will be? Another big problem here that I see is, just how useful (and measurable) is Nominal Cell (or pack) Voltage. How would you go about teching a boat for pack legality? A fully discharged cell (under no load) will read nominal cell voltage. How practical is that to tech on raceday?

A fully charged cell (off the charger) will read a higher than nominal cell voltage. I think that Nicad and Nimh packs will generally stabilize around 1.45 volts per cell fully charged and I have read that LiPoly cells, fully charged are about 4.23 volts. Perhaps Steve Hill could shed some more light on these numbers. This pack max voltage could be relatively easily measured prior to a heat race and if the correct values were chosen, could be valid as class designators for quite some time to come no matter what battery technology.

This might also be a perfect opportunity to have a serious look at the number of voltage classes that we have with the idea, perhaps, of reducing the numbers some by combining voltages. I have some further ideas in this direction but first I'd like to get your opinions and observations so far.

Comments.....

 

[CySlyde]

thabx for explaining this class stuff... i always got lost, now maybe i'll be able to plan a good FE... just outta question where do dual motors come in in the class structure? and how aout gearing?

thanx

-=cy

 

[Dan Chase]

All other cell count classes ( O, P, Q, S, & T) are Open motor classes. The only exception is the Spec Motor class - LSH (Limited Sport Hydro). This is a 12 cell sport hydro class using a standard spec Motor (700 size)

Doug, there is another exception,

ECO- 6 cells submerged prop 19t Limited Modified Motor.

Other exceptions to the letter designation.

OPC- 12 cells tunnel hull with open outboard motor & Drive

1/10 Crackerbox- 6 cell flat bottom with ROAR stock motor

Good thread guys! I have been lobbying for years to do away with the letter designation, I spend more time explaining classes at our club races then I do racing! It took me a full year before I knew the class with out doing my alphabet and counting on my fingers and toes!

Added, Ooops, OPC is P OPC Tunnel.

Can we make this anymore confusing?

 

[Kevin Whitehead]

thabx for explaining this class stuff... i always got lost, now maybe i'll be able to plan a good FE... just outta question where do dual motors come in in the class structure? and how aout gearing?

thanx

-=cy

M,N, Crackerbox, LSH, maybe ECO(?) classes: One motor only

O,P,Q,S,T: Any number of motors

All classes (except Crackerbox): Any gearing desired

1/10 Crackerbox: No gears - Direct drive only

KW

 

[Dan Chase]

ECO is also single motor only.

 

[LOU]

Hows this look for a transition plan. Since Li po's will have more capacity they get the the lower voltage.

Was N- 6cell, 6 nicads 8.7 volts- 2 series li po 8.46 volts-- Class name--N

Was P- 12 cell, 12 nicads 17.4 volts-4 series li po 16.92 volts--Class name-- P

Was Q- 18 cell, 18 nicads 26.1 volt-6 series li po 25.38 volts--Class name--Q

Was S-24 cell, 24 nicads 34.8 volt-8 series li po 33.84 volts--Class name --S

Was T- 32 cell, 30 nicads 43.5 volts-10 series li po 42.3 volts--Class name--T

???

LOU

 

[guiri]

I think there are some safety concerns to be overcome with LiPo's before we can think of making packs up of 10 in series and 4 or 5 in parallel to be able to deliver the current required. If it happens during a run, then there'll be plenty of water : but accidents seem to have happened to fliers of some experience while charging or transporting packs.

In the hurly-burly of racing and the general pressure of competition, damage, which perhaps only subsequently turns into a disaster, may arise. Until the safety issues are addressed, a limit on the watt/hours available might be advisable.

 

[LOU]

Hey Guri 10S ??? : I agree but this is ment to get people thinking about class specification by volts rather then # of cells.

How about

N being 9V

P being 17V

Q being 26V

S being 35V

T being 43V

Of course T,S,Q would probly remain Nicad or Nimh until Li po tech caught up

 

[forresterace]

OK Pete

Now you're starting to think more logically and better grasp the task at hand. However, your still missing one of the concepts that I threw open for consideration - consolidating classes.

We are never going to be able to reduce the number of different hull classifications. Each style - mono, sport hydro, rigger (hydro) and Offshore have their own following and nobody is goin to give them up. The only possibility to reduce the number of combinations is to reduce the number of voltage groups. Why do we need six different voltage ratings (N,O,P,Q,S &T)? Let's face it, 4 cell was a momentary blip on the horizon - never to be seen again.

How about if we reduce the voltage-based classes to four?

Proposal:

Class I - 11 volts max (fully charged pack)

Class II - 18 volts " "

Class III - 27 volts " "

Class IV - 47 volts " "

 

[Kevin Whitehead]

How about if we reduce the voltage-based classes to four?

Proposal:

Class I - 11 volts max (fully charged pack)

Class II - 18 volts " "

Class III - 27 volts " "

Class IV - 47 volts " "

Why 11V max?

That would form a freaky 7 cell set-up for the sub-C users.

9V max would keep the 6 cell set-ups intact and the LiPos would still fit right in at 8.46V.

What other battery technology is just over-the-horizon?

Is there another technology that could eclipse LiPo before a solution to the current-handling problem is solved?

KW

 

[Andrewg]

why introduce lithium poly into the race classes at this stage

let the price fall a little then take it up