Pump Jet Kilo

[crazy ivan]

BD, can you post a

BD, can you post a copy of that to You Tube? All I see here is a blank screen that has the Photobucket logo in the upper corner, and arrows in the bottom corners, all flashing rapidly.

[bigdave]

Maybe it's time you upgraded

Maybe it's time you upgraded from the Commodore-64 to a real computer!! Ha!! BD.

[crazy ivan]

Unless you're buying, Buddy, that

Unless you're buying, Buddy, that is so-o-o-o-o-o NOT gonna happen!

[Larry Kuntz]

Great video Big Dave. I

Great video Big Dave. I think I actually saw some water at the bottom of the frame. I told you to throw Steamboy in the pool, then we would have some great underwater video.
Patti's speedboat looked great in the video.

[seahorse]

hey, I got your "steamboy"

hey, I got your "steamboy" right here

I can see there are lots of experts out there with the Oregon digital camera. Having it strapped to a pole inserted in the water is no picnic. It's not like your looking through a view finder so there is no way to adjust any distances or to properly track a sub.

I was able to take great shots of Larry's Akula and Don's Boone. Dave kept getting to close to the camera. I guess he wanted a close up

[pirate]

I understand the funnel confusion

I understand the funnel confusion Dave, I had it on my Seawolf and Virginia. But in reality, that is what creates a higher pressure of the water going out than coming in, as in a jet engine. Especially since there's no heat source to expand the flow going through, as on a jet engine. The thrust out has to be greater than the thrust in, the more compression you get with the taper, the more efficient the propulsion. Think of it like a fire hose nozzle. The key is to have a power source and prop that can work to force the higher pressure.

I think I was fighting the same issue with mine, but when I used a more efficient prop inside, the funnel effect did increase the thrust. The problem is the scale I think. I'm thinking as things get bigger, the returns get greater. Maybe it has something to do with the size of the water molecules—they're much larger in comparison to a small scale propulsor than a large one.

Anyway, I'd keep the funnel effect, but concentrate on using a more efficient prop than an accurate to scale one, then I think you'll get better results—I did.

But even so, what it looked like in the video you were getting a lot of speed, especially for scale.

Pete

[bigdave]

I agree with you Pete.

I agree with you Pete.
I need more bite to my impeller.
I do think the PJ on the Alrosa is more of a Jet Pump than a Pump Jet. I am not sure if the terminology is correct.
The JP is meant to accelerate the water to push against water or air like a jet engine. The PJ is meant to move larger quantities of water but at a slower speed to push the sub or boat.
The taper on the Alrosa is much steeper that the Seawolf. More of a funnel effect.
Here are some shots of my impeller and the inside of the JP. The impeller is just too small to push enough water. The Alrosa in the video is going much slower than it looks. BD.

[bigdave]

Here is another video I

Here is another video I just uploaded. Watch the bottom of the screen again. You will see the Alrosa get passed by the much larger Holland and get sucked into her wake. I finally break free and head off to the right and end up bopping the side of the pool. As usuall!! BD.