Pump question

I was curious about the rationale behind the gph limit on the pump. I come from a fast gun format, so I have no experience with a rate limited pump. Why not have a restrictor and let captains decide how much space/weight via batteries/motor they devote to damage control? Doesn't a gph limit mean that a ship of size x will sink with roughly y number of holes? I'd rather have more control of when I sink/strike. Just asking, as I said I have no experience with this method of pump restrictions.
And yes, I do plan on starting a ship once my Bismarck is off the building slip. The Commerce De'Marseille.

 

I could be wrong, but I think this is exactly the point, it would more reflect what would happen in full a scale ship with x amount of displacement with y number of holes in it. Big gun tends to design rules to allow ships to "reflect" their historic ships construction, as opposed to trying to make a somewhat leveled out field such as fast gun. Fast gun rules tend to even out the ships a bit to try to encourage more different ships on the pond by making some less capable ships more r/c battle worthy. The big gun rules tend to more accurately reflect each ships individual characteristics regarding speed and armor etc. The negative effect of that is that fewer people want to build less battle capable ships.

 

I would think requiring spec pump systems would tend to even things out more that a restrictor type system, since you can get the flexibility to decide to run more ah and a robust motor in the latter. I guess I'll just have to see how I feel about it when I try it.

 

There really isn't such a thing as a spec pump. Sure, the pump housing could be the same but motors, even the same brand, make type, etc, can still vary in performance. Also, regulating the tech means inspecting the tech and trying to catch all the tiny things that can be done to make a "spec" motor perform better.

It really is easier and simpler to regulate the end result, i.e. gpm. gpm is easily measured and can be done without removing anything from the boat. Retesting is a snap for that very same reason. Regulating the output also allows more varity in pump systems. A person can go with a small motor and open outlet, or use a restriction outlet to control the gpm.

 

think im going to stick to fast gun for the moment

 

I guess it may just be that I started in fast gun, but I like the idea of a restrictor vs a gpm limit.

 

Funny, I've done nothing BUT fast gun, and I dearly wish we'd go to a gpm limit to cut down on the "superpump" tech wars.

 

What exactly is wrong with advancing pump tech? I know the point is to be able to sink boats, but at a certain point it seems like we might as well just poke ten holes in the boat before we start. Don't get me wrong, I don't want it to be who can buy the most expensive stuff for his boat, but gpm limits seem to be too much of a handicap.

 

I can't see any valid argument against gpm limits. Like stated previously, it's very easy to measure, works irregardless of what technology is running the pump or even what orifice / restrictor / outlet is used. The only ones I could see being against it are those perceiving some sort of advantage for themselves under the current rule.

 

Testing and Enforcement is significantly easier with a set diameter outlet, GPM is harder/less convenient to measure. It would also increase the amount of time spent testing on Sunday as people would have to test, adjust, test, etc till they got a flow rate that they liked. (similar to speed testing where people push to be 24.05 vs 24.3) It isn't super easy to adjust at the lakeside without an ESC, you can pinch the outlet tube or something I guess but fewer things to adjust seems like a benefit. In addition GPM limits reduce the incentive for people to tinker and experiment with new stuff which is a big draw for a lot of people. (saving 1 Ah because your pump is more efficient is way less sexy than pumping 0.5 GPM more...then again with physics being what it is we're very much at the point that to get significantly more flow the additional power required is tremendous...?yay? pump affinity laws..)

That said I think GPM aligns with how most of the other rules work better in that it regulates an end result and not how you get there (so it does get some points for allowing innovation, you just don't get too much from your innovation, not that you get a ton from your innovation with how pumps preform currently anyway...), also it sets a defined standard for what a Defensive unit is in terms of performance better than a diameter (an Offensive Unit basically being ~50 BBs) which I think is a nice to have. It would probably increase reliability since the amount of current that equipment would have to deal with would be significantly less and pumps/other parts would be stressed to much lower levels.

I'm not convinced that one is better than the other or if they are just different. Realisticlly I think the hobby would be just fine and fun to play with either.

 

I tend to agree with the gpm limit crowd. The idea is to build, battle, and sink boats, not so much design killer power hungry pumps. If the pumps were limited, it would reduce how much went into the boats just to be competitive. In my opinion it would reduce the engineering overhead and learning curve which would make it easier for new guys as well as veterans who want to build boats, not pumps. It would also help control the cost of putting a competitive boat on the water by reducing battery requirements, and controlling the cost of the pumps, and reducing the need for higher draw capable wiring and switches.

 

Patching is covered by striking when you've had enough, and I haven't seen that folks are pricing people out of competition yet ( I may be wrong, as I've just gotten back into the hobby). One of my measures of how good a battle was, besides dealing some damage and not sinking, is how hard was I to put down- did it take some effort to sink me? I don't like feeling like I'm am forced to sink after I have a set amount of belows. Not arguing for a rule change, just had been curious as to the rationale behind the different pump method.

 

At the end of the day, I see some valid points, but I'm not convinced that the gpm route is better. That being said, I've never battled with it, and so until I do, I plan keep an open mind.

 

The testing process is a bit of a concern as well from a simplicity standpoint. In the past, my pump systems have been just a switch with a servo. How difficult is it to get a pump at the right rate, and what sort of stuff is required? What the general testing procedure? Might as well plan now before I actually start my build for AOS.

 

Rationale is they think gmp limits will make everybody equal, and that good pumps are difficult or costly, or push up the cost of a ship. I completely disagree.

First, the guys who dominate the game are the ones who can hit what they shoot at. They will still kick butt with GPM limits, probably even do much better since they won't have to work as hard on any single opponent.

Second, pump housings and impellers all cost the same, Outlets and motors are the primary source of improvements lately. Outlet costs maybe $1 to make. You should have several. Brushed motors won't quite keep up with brushless in a power or efficiency contest. Brushed are cheaper per motor but a lot less reliable, they tend to burn out much more often. So burn out 6 $16 brushed motors (and sink or delay your game) over two years or use a $48 chinese brushless/esc combo and don't burn it out. Choosing brushed or brushless more a reliability issue than a cost issue. Some guys use 2 brushed motors, and get roughly the same reliability (because there are two) as a brushless and about 1.5 times more GPM capacity than a single "good" brushless. Anybody who puts a $3 brushed surplus motor in their ship to drive the pump deserves what they get. Pumps work the same no matter what batteries you put in the boat. People have been sticking lightweight but expensive NiCads or LiPo cells in ships for years. So the cost argument is completely bogus imo.