Should I cut out the sides around the pump to get more water Flow around the inlet? I’m finding that when I turn the pump on to 100% I get a spray out of the outlet instead of a nice solid stream. Would that cause this issue?
Spray is good, it’s a higher flow rate than the solid stream. I recommend hose clamps on the pump outlet tubing and hose to restricter
Great minds think a like. I put pipe clamps on both my ships today. can we nerd out of pumps for second? Why does the higher pressure/spray mean a higher flow rate? To my uneducated pump mind a spray would mean that air is filling that space?
well, @notSoGnarly and I did a bunch of testing using that exact pump and motor on various voltages.... I'm sure he could drop in with our data
The higher flow rate is from the pump spinning faster from higher power brushless motors. The power consumed for the higher speed goes up proportionally to the speed change, to the third power (going twice as fast consumes roughly 8x more power, for some portions of the pump curve). To your question of why the flow ‘separates’ and becomes more of a spray than a stream, I would guess it has to do with the velocity of the water going through the center of the restrictor and the angle of the converging and diverging portions of the restrictor so the water can’t ‘stick’ to the increasing diameter portion from boundary layer deterioration
When I asked to nerd out you went all out. So what your saying is the volume coming out has nothing to do with the visuals of the water stream...
"Yes" I would still remove material around the pump body to allow more water to collect in/around it, especially with a nice high perf brushless setup. I experimented with a bunch of different things before settling on what I'm now offering as the SJS pump. I've found that, especially with faster brushless motors, moving up to 1/2" vinyl outlet tubing vs the hobby longtime standard of 3/8 does result in a slight performance bonus. The length of the vinyl also will have a noticeable impact on the pump visual. Matt Andrew's Baden with an SJS pump and about 3~ inches of vinyl creates a massive pressure washer stream at full power. It's downright impressive, arguably usable as an offensive unit. My Jean Bart's same exact pumps with about 6" and 9" of vinyl produce very solid garden-hose looking streams.
Well it sounds like I have another winter project to put on the list for the Biz. My outlet pipe is about 3" long but the old brass style.
Yeah, a little more room around the pump body may help. You've only got gravity and atmospheric pressure moving water under the housing and into the impeller area. If you recall, my Big Gun Mikasa (with brushless pump and a 1/4" outlet) was effectively only limited by the area around the pump. It was so limiting that I had to replace an entire section of the hull just to get better flow.
So what your saying is make the area as big as possible? Im going to get this cut out and you guys are going to be in real trouble then... LOL
"Yes" Water channeling and creating a sump for the pump are a bit of an acquired art. I don't think I've even really figured it out. But you absolutely want the pump sunk as low as possible, with a nice basin around the pump for water to collect. In my most modern kits, I use a 3-3.5" diameter circle centered on the pump motor shaft as the cutting tool to create the pump basin, if that gives you an idea to aim for.
Cool. I was curious how big it should be. In the Bismarck, I feel quite confident I could get 3.5" in there.
Keep in mind this is 1 person's build technique, you might end up with 15 answers to this question. Taking spy photos from build threads and in person at battles is key when it comes to specific build techniques like this topic.
Sure. I understand. I am taking it as a starting point and can adjust as new (maybe better) information presents itself.
lemme show ya what I'm doing for the Dale Earnhardt Project. it's very similar to what Will does, because he gave me the ideas I ran with. so I build the hull completely separate from the internals. it allows me to try really strange things and still not futz up too much. so here's what it looks like without the hull so I have the forward pump up on a 3/16" high platform right at the end of the water channeling. the aft pump is at the lowest aft-most part of the hull and the area around both pumps acts as a sort of "Parlor" with all of the sides sloped toward the aft pump. the hydrology of the hull says "you go there, sloshy stuff", and there is plenty of sloped room in there forcing water to the pump to keep it from stalling out. The elevated forward pump (The pump will be a bit further aft than in the below screenshot, Lads. I'm still dialing in this gut sled) is elevated on the advice of @Beaver . The general jist can likely be explained better by the Northeast guys since they invented the idea, but in practice the forward pump is the "Giver da GOOSE!" pump, which will keep her alive after I spend an entire sortie trying to do something terribly stupid like sink @Bob with my wal-mart brand Nagato
That is quite the setup. I am distracted by this image. I understand whats going on with the slopes. But whats up with the "pockets"? Wont those trap water?
they're pockets for ballast. in the form of Lead birdshot mixed with epoxy. they'll be completely filled in and flush with the rim
