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Chilli
12-02-2013, 12:55 AM
New issue of the Roostertail is online. We have new FE safety rules pertaining to class voltages during record trials events. There are also some rules proposals to vote on. Thanks to Chris Harris the National FE director and Doug Smock the records director for their work!!

http://www.impba.net/attachments/article/152/D13%20EE%20Final.pdf

HOTWATER
12-02-2013, 05:45 PM
Hopefully online voting will be up on the website soon!

don ferrette
12-04-2013, 12:51 PM
The on line voting on the IMPBA web site is now available but you must be registered on the site. If you are not registered yet please do so not only to vote but the web site holds a vast amount of good information for IMPBA boaters. Also even though a number of the rule proposals to vote on are regarding IC power they are still important and I'm hoping all will vote on and support the proposals especially the strut location on sport 40s. That is the only class that currently does not allow transom mounted struts like every other sport hydro class in the IMPBA does and I'd like to see consistency among those rules. Thanks in advance to all members who take the time to vote and make their voice heard. :smile:

keithbradley
12-05-2013, 02:06 AM
Thanks to Doug, Chris, and all others involved in getting us a solid standard for starting voltage in FE classes. This was greatly needed IMO not only in regards to the integrity of our records, but as a means of simplifying what was a somewhat confusing classification. 4.23v/cell is straight-forward and completely reasonable. :thumbup1:

I would like to ask, to any onlookers who might have the info:

Does the -17% figure still apply to minimum voltage, or is the minimum voltage for a class just based on the upper limits of the next lowest class?
For example, Q classes are limited to 4.23v * 6 (25.38v) max. Does that mean that the voltage parameters for S are 25.39v-33.84v? It may seem like an odd question, but it's not unlikely for a Q boat to run 5s, or a S boat to run 7s, T boat to run 9s, etc.

Doug Smock
12-09-2013, 08:38 PM
Thanks to Doug, Chris, and all others involved in getting us a solid standard for starting voltage in FE classes. This was greatly needed IMO not only in regards to the integrity of our records, but as a means of simplifying what was a somewhat confusing classification. 4.23v/cell is straight-forward and completely reasonable. :thumbup1:

I would like to ask, to any onlookers who might have the info:

Does the -17% figure still apply to minimum voltage, or is the minimum voltage for a class just based on the upper limits of the next lowest class?
For example, Q classes are limited to 4.23v * 6 (25.38v) max. Does that mean that the voltage parameters for S are 25.39v-33.84v? It may seem like an odd question, but it's not unlikely for a Q boat to run 5s, or a S boat to run 7s, T boat to run 9s, etc.

Thanks Keith and Mike!
Not a odd question at all Keith.
Here are the new class voltages that will appear with the update of the rulebook. The +/- 17% will go away.

N- 3.7 to 8.46
P- 11.1 to 16.92
Q- 18.5 to 25.38
S- 25.9 to 33.84
T- 33.3 to 42.30

keithbradley
12-09-2013, 10:32 PM
How are the lower limit numbers determined? I can't seem to find a pattern that fits all classes...
The T range seems tighter than the other classes for some reason. For example, you could run 7s at as low as 3.7v/cell in S, but a 9s setup with cells at 4.1v each would not qualify for T.

If I follow the pattern for classes N through S, T should be 33.3v to 42.3v. Are you sure that wasn't a mistake?

Doug Smock
12-09-2013, 10:42 PM
Are you sure that wasn't a mistake?

I was just making sure you were paying attention.:wink:
See above:beerchug:

T.S.Davis
12-10-2013, 03:39 PM
Question.

With NAMBA, if I have a 33.5" boat and I drop 5s in....it becomes a Q boat. Is that how it works in IMPBA too?

Fluid
12-10-2013, 03:53 PM
Not in IMPBA Sport Hydro. Your 5S boat would be illegal to race in any Sport Hydro class.


.

Chilli
12-10-2013, 04:08 PM
A Q Sport Hydro has to be greater than 34 and up to 40 inches in length to be legal in the IMPBA. All other Q classes just have the 40" max.

T.S.Davis
12-10-2013, 08:32 PM
Think I got it. Lower limits on the sporties.

Makes sense to a degree. All the boats will be similarly sized and powered. Provides parity and that scaley "look". I know the "look" factor has always been subject to debate but I'm okay with it.

Shooter
12-11-2013, 07:33 PM
Does IMPBA have a (transom)/(sponson ride width) ratio rule? I just layed out a Whip 40 and it calculates to exactly 0.65. (8.5"/13"). This is at the exact minimum limit for NAMBA!

Chilli
12-11-2013, 08:49 PM
From the IMPBA rule book, Section J: http://impba.net/attachments/article/132/Sec-J,_Fast%20Electric%202013.pdf
The width of the bottom of the transom must be 65% or more of the width between the forward riding surfaces. On a shovelnose hull that has a tapered transom bottom the 65% rule will apply to the hull bottom at a point three a one half inches forward of the transom.

keithbradley
12-12-2013, 12:38 AM
A Q Sport Hydro has to be greater than 34 and up to 40 inches in length to be legal in the IMPBA. All other Q classes just have the 40" max.

What's the reasoning behind a minimum hull length in sport hydro?

T.S.Davis
12-12-2013, 08:48 AM
I can't speak for IMPBA but I do remember the conversation back when we were cooking limits.

Sport is thought of by some as a watery version of scale. Full bodies hydros that look similar in size and shape. Less restrictive than scale but still sorta scale looking. Hence the ratio limitations we have in NAMBA. We were trying to keep the riggers out of sport hydro.

When we chose not to have the lower limit in NAMBA we were thinking that guys could cross over. Maybe run 6s in a P boat so a traveler could run another class. The reality seems to have dictated otherwise. A 33" hull on the power that's available in at 6s simply will not finish. In traffic after maybe 2 laps of chop......not gonna happen. So nobody messes with it.

The only place I think you might be able to exploit the lack of a lower limit is SAW. Once upon a time there was a Q Sport saw record in IMPBA that was set by a little tiny sport shovel. It held for years. I'm guessing they were trying to avoid that.

Wild speculation on my part. Maybe Doug will remember.

Doug Smock
12-12-2013, 04:52 PM
I can't speak for IMPBA but I do remember the conversation back when we were cooking limits.

Sport is thought of by some as a watery version of scale. Full bodies hydros that look similar in size and shape. Less restrictive than scale but still sorta scale looking. Hence the ratio limitations we have in NAMBA. We were trying to keep the riggers out of sport hydro.

When we chose not to have the lower limit in NAMBA we were thinking that guys could cross over. Maybe run 6s in a P boat so a traveler could run another class. The reality seems to have dictated otherwise. A 33" hull on the power that's available in at 6s simply will not finish. In traffic after maybe 2 laps of chop......not gonna happen. So nobody messes with it.
The only place I think you might be able to exploit the lack of a lower limit is SAW.
Maybe Doug will remember.

I think you're on it Terry.
This came up recently and I couldn't remember. Went hunting and couldn't find anything specific.(never want to go back there BTW) I had a conversation with a senior racer this week that remembers it like you do.

Doug

don ferrette
12-12-2013, 08:01 PM
There is one proposal #13-011 up for vote that even though it pertains to sport 40, the nitro version of Q sport hydro, I would like to ask that the IMPBA FE racers vote and vote YES to this and support it. Why? Out of the eight sport hydro classes for FE, nitro and gas in the IMPBA it is the only one that does not allow transom mounted struts. There are many of us that would like to see this brought in line with all the others for the sake of consistency in all our sport hydro classes. I tested it both ways that last time I owned a sport 40 and found no significant advantage either way. Please take a moment and vote in support of this proposal. :cool:

keithbradley
12-13-2013, 01:07 AM
The only place I think you might be able to exploit the lack of a lower limit is SAW. Once upon a time there was a Q Sport saw record in IMPBA that was set by a little tiny sport shovel. It held for years. I'm guessing they were trying to avoid that.


Nobody could beat him with a bigger boat? :confused2:
Perhaps this was during a time where it was technologically advantageous to have a smaller hull? I don't know how it would be, but that's the only way it makes sense.
The only situation I can see where having a smaller hull would be advantageous is in T-cat, or perhaps other T classes, and that's really only because of the 25lb. weight limit rule. Even in this case, I don't think you could go faster with the smaller cat, but you would be able to build it strong enough to take a crash, where in the case of a Twin powered T-catamaran, coming in at under 25lbs RTR requires cutting some corners and possibly building a cat that is much weaker than preferred.

I found it interesting too that Q+ Monos, cats, and riggers can all run twins, but sport hydros can't. Apparently the sport hydro class has a coveted history in some respect.

Chilli
12-13-2013, 10:02 AM
Like the guys mentioned above. The Sport Hydro class was probably designed to be a semi scale class. That's the reason for the no twins restriction and hull dimension/cockpit rules.

I have no idea about why there are no minimums in the other classes or why all riggers can be up to 60"s, but I have allot of respect for the guys's that go fast in the smaller hulls. I believe Mike Martin's 78 mph run in P-Mono was done in a DF 26 and to me that's one of the more impressive records out there. I do like the no minimum rule for most classes. It allowed me to take a 32 inch $100 hull over 95 mph with a $100 clearance ESC and a $170 clearance motor. The lessons I learned about preparing a hull for SAW's and getting the proper set up to keep her on the water were priceless. I know it's only a matter of time before my record gets trounced by a bigger twin, but I'm proud of what I accomplished. Someone just has to put the $$$ and effort into it. To tell you the truth, I wish twins were a specialty class for the FE boats like they are in all the Gas and Nitro classes.

T.S.Davis
12-13-2013, 11:29 AM
I think that old Q sport record was set before Lipo. Dark Horse shovel on 16 sub C cells. My memory may be off on that. I actually hope it is because I can't remember breakfast from today.

Q Sport was barely even an idea before LiPo. Wasn't practical. It was on the books I do believe but nobody had figured out how to go fast on 18 cells without building a custom one off rigger. A sport40 hull like the Thomas would bake a set of 18 sub C 4200mah cells in no time.

It really wasn't until about 2009.....ish that guys started figuring out Q sport setups with Sport40 hulls. Honestly, the best setup for Q sport is still the setups that were cooked up back then. It hasn't gotten better. 1527/1y is still the perfect combo. We just have better batteries.

SAW is a different animal. I actually have a Q saw setup but I'm a'scaird.

keithbradley
12-13-2013, 02:05 PM
I know it's only a matter of time before my record gets trounced by a bigger twin.

Why on earth would you think that??? Who would do such a thing? :spy: :tt2:

I disagree with you regarding the specialty class.
I don't like the idea of exiling everyone who excels (especially when it's me).
If we want integrity in our records we need to create an atmosphere where people can reach the highest levels, not one that allows those who can't keep up to continue being competitive be weeding out the competition. It would be different if there were a bunch of people running twins in the IMPBA, creating the need for more classes, but there aren't. I suggest that anyone who believes they can't compete because they don't run twins should build one and give it a shot.

If memory serves me correctly, I recall you saying that twins don't really offer a performance advantage and are really just for bling. Do you still believe that?