Water pickup drag testing

[jaike5]

Some of the guys up here in the great white north think out side the box .... well several boxes ! JB weld/epoxy brass tubing down the back of the rudder( clean and ruff both surfaces) with just a hair past the bottom of the rudder or less. worked very well for Marc Andre's p-hydro
Cheers, Jay.

[kfxguy]

So if. you want to make a good test try a knife rudder in this cat

Scared to. It's dialed in nicely and if I decrease rudder drag it's likely going to blow over.

[grsboats]

So if. you want to make a good test try a knife rudder in this cat

[kfxguy]

Travis I always run riggers and can tell you that using a knife rudder on my saw nitro and FE boats there is significant difference in speed....I'm curious to see in your boats too .Gill

Let me give you a nice laugh. 100. Mph. Saw. Boat. Rudder. Lmao

Look how long

[grsboats]

Travis I always run riggers and can tell you that using a knife rudder on my saw nitro and FE boats there is significant difference in speed....I'm curious to see in your boats too .Gill

[Hotrods]

[kfxguy]

Ya lets see info on all three. Ya know placement of the j-tube makes a lot of difference too for oval racing I try to get a little closer to the hub and SAW's it is out and higher. I was weighing S-15 props to day, every little thing adds up.

I'll be able to do the bottom pickup test this weekend. Probably be next week before I can do the prop wash vs rudder pickup. I really need to set a boat up that has all of them.

[kfxguy]

I think the lowest drag water pickup system is the raindrop pickup with a reversed raindrop outlet. The water rushing past the outlet (on the left of the picture) sucks the water out by creating negative pressure in the line, thus negating the positive pressure drag, on the pickup.
You just can't see if the system is blocked or not while the boat is running. Very common in Europe.

Holy damnit. That's a good idea. Thanks for that! I've seen the gundert ones but I like this much better. My builds are now going to change a bit. I guarantee that's the least drag setup there.

[RandyatBBY]

Ya lets see info on all three. Ya know placement of the j-tube makes a lot of difference too for oval racing I try to get a little closer to the hub and SAW's it is out and higher. I was weighing S-15 props to day, every little thing adds up.

[785boats]

I think the lowest drag water pickup system is the raindrop pickup with a reversed raindrop outlet. The water rushing past the outlet (on the left of the picture) sucks the water out by creating negative pressure in the line, thus negating the positive pressure drag, on the pickup. Well, to some extent at least.
You just can't see if the system is blocked or not while the boat is running. Very common in Europe.

[Mxkid261]

Curious to see what you find, I put sponson pickups in my rivercat this past weekend after I fixed the front seam

[dmitry100]

kfxguy: If you want to give it a shot with good pump-- I can give you a link to a good one. Cheap too.

[NativePaul]

I am interested to hear the results of the tests.

While not perfect, I think taping up the hull bottom pick up will be a good enough test.

I suspect the vast majority of the drag from a rudder pick up comes from the thicker blade rather than from the pick up itself, do you have a thinner wedge the same size that you can swap it with?

Can you t ry both behind the prop, and above the prop pickups, I think there will be a big disparity between the two.

[Turbo Dan-O]

[kfxguy]

Top SAW's (142mph+) in Germany do not use our standard "raindrop" water pickups -- they instead use plain small 3mm holes but with the assist of water pumps. Would not doubt if a water pump would help with the drag in general. Scooping up water like a rain drop style pickup would technically create drag right... but how much drag exactly?

I'm going to find out