Water pickup drag testing

[kfxguy]

I'm glad I made this thread. I've learned (or gained a few good ideas) a few things. I have one of those small pumps posted in the link. I may find something smaller tho.


Question. If I do a water pump, do I do a straight up and down (not angled to scoop water in) pickup on the bottom of the sponson? You guys think it would pick up water at speed?

[Turbo Dan-O]

[url]httpDan o, I have some of those fittings and they are huge. Like 1/4 Id hose fits on the nipple. Lol

Yikes, never mind!

I'm pretty sure I have seen some with 4mm outlets before though...

Something to look into later maybe.

Edit: Kintec has some with 5mm fittings. Maybe that's what I was thinking of.

[dmitry100]

kfxguy, the pick up is just a straight hole... the pump does all the work to pick up the water. Just straight up / down.

[T.S.Davis]

I actually have been thinking about this for a while but not for the friction issue. Just as a means to cool everything right after the run when I'm not really moving.

I don't think that these pumps are turning enough rpm to burn themselves up in the time it takes us to get from the bench to the pond. Experimenting at these costs wouldn't be bad. plug er and wait fer the burn out I suppose. I know our fire pumps will run for quite sometimes without a fresh supply over water. It;s pretty horrible when they fail but it isn't immediate. I'm not suggesting these are any where near the quality of a $75k pump but the theory is similar.

If the pump is self priming I don't think it matters how the water pickup is pointed. The only thing would be, can it suck water if your at speed? It may skip past the opening due to velocity.

I was thinking about using a pump and a bypass. You put a mini check valve (think aquarium check) in the bypass loop. This way high pressure water from the pickup takes the shortest route (through the system and not the pump in theory) and the pump doesn't just push water out the pickup when your at rest. This way you can get full flow from a pickup and still the benefit of a pump.

Sorta like this.....

PUMP SYSTEM.JPG

[dmitry100]

TS Davis, that's the idea of a diaphragm pump ... it can pass water as fast as the water is coming thru, ie. if the pressure of the inlet is higher than the pump, etc.

https://en.wikipedia.org/wiki/Diaphragm_pump

The gear based pumps on the other hand should be spinning really fast if the pressure of inlet is high naturally, either way it would make it easier on the motor and would probably just help spin the gears faster... I would think so anyway lol.

[T.S.Davis]

I was worried that if a geared pump were allowed to free spin with the incoming water that it may actually generate electricity. If we're running it off the RX..............maybe it's not an issue. I just don't have a feel for how much water is actually coming through our systems normally. It may be no more than the pump is capable of to begin with.

The diaphragm negates the problem entirely.

[kfxguy]

I actually have been thinking about this for a while but not for the friction issue. Just as a means to cool everything right after the run when I'm not really moving.

I don't think that these pumps are turning enough rpm to burn themselves up in the time it takes us to get from the bench to the pond. Experimenting at these costs wouldn't be bad. plug er and wait fer the burn out I suppose. I know our fire pumps will run for quite sometimes without a fresh supply over water. It;s pretty horrible when they fail but it isn't immediate. I'm not suggesting these are any where near the quality of a $75k pump but the theory is similar.

If the pump is self priming I don't think it matters how the water pickup is pointed. The only thing would be, can it suck water if your at speed? It may skip past the opening due to velocity.

I was thinking about using a pump and a bypass. You put a mini check valve (think aquarium check) in the bypass loop. This way high pressure water from the pickup takes the shortest route (through the system and not the pump in theory) and the pump doesn't just push water out the pickup when your at rest. This way you can get full flow from a pickup and still the benefit of a pump.

Sorta like this.....

[ATTACH=CONFIG]143650[/ATTACH]

I think this pump idea is great. For saw use. More of a novelty I've always thought for anything else but seeing how a two pass saw run is made where you made a pass and then left the boat sit and let the wake subside......while its sitting the temp creeps up unless you have water flow. So I thing it's going to be awesome to have on a very hot setup.

I've notice in my data logs that after I make my pass the temp creeps up. Sometimes higher than I like and if that's the case and I make pass again I could toast something. So I think it's worth doing.

[dmitry100]

TS Davis, how big of a boat are you planning to use that diaphragm pump on? It weighs about 100 grams.
If you want dimensions ... let me know.

[T.S.Davis]

Actually the spec boats are the most susceptible to heat creep at the end of a 1 mile heat than my big boats. I suppose heat is the enemy in all our boats though. The motor quality is such that I worry less about it in open boats.

Ball had mentioned in some other thread a few weeks ago that his temps climbed substantially on the way back to the bench from the pond. My thinking is that I can allow the boat to cool right there in the pond like Marty Mcfly in Back to the Future.

An extra 100 grams is a bunch. Might have to go back to a geared pump with the check. Cheap pumps and relatively small.

[kfxguy]

Actually the spec boats are the most susceptible to heat creep at the end of a 1 mile heat than my big boats. I suppose heat is the enemy in all our boats though. The motor quality is such that I worry less about it in open boats.

Ball had mentioned in some other thread a few weeks ago that his temps climbed substantially on the way back to the bench from the pond. My thinking is that I can allow the boat to cool right there in the pond like Marty Mcfly in Back to the Future.

An extra 100 grams is a bunch. Might have to go back to a geared pump with the check. Cheap pumps and relatively small.

That little pump I posted only weighs 55g. I think I'm gonna try one of those in the Rivercat.

[dmitry100]

Ts Davis, perhaps look around ebay to see if they have a diaphragm pump in a smaller size... I think I might of came across a few.

[Nikolas Andriop]

Anyway you provided me a link to this pump?

Here you are.....http://www.ebay.com/itm/Mini-6V-12V-...YAAOSwxCxT8cTB

Here is mine...IMG_6109.JPG

[kfxguy]

Check this out. If money wasn't a factor......

http://www.ebay.com/itm/231587767607?redirect=mobile

[Nikolas Andriop]

I think that isn't worth it....
It has toooo little flow rate

[runzwithsizorz]

A very old thread I had bookmarked about the subject of pumps. http://www.rcgroups.com/forums/showt...=590807&page=4