Water pickup drag testing

[martin]

The advantage of no water pick up in the rudder is a thinner rudder or better still a knife blade rudder producing much less drag.

[banixj]

On top speed record boat some guys use a strange cooling system, some time i read "high pressure" cooling system or air/water cooling...
No more info on the web, but tubes are so small...
Some pic there:

http://www.hpr-powerboats.com/sale/

What do you know about that?

[TRUCKPULL]

On top speed record boat some guys use a strange cooling system, some time i read "high pressure" cooling system or air/water cooling...
No more info on the web, but tubes are so small...
Some pic there:

http://www.hpr-powerboats.com/sale/

What do you know about that?

Francesco - The first boat has no water cooling installed, it does have intake ports in the sponsons.
The second boat- Air cooling (every motor has that to some point, some large motors also have fans in them)
This boat also has a 12V water pump in it, with the intakes in the sponsons.

Larry

[kfxguy]

On top speed record boat some guys use a strange cooling system, some time i read "high pressure" cooling system or air/water cooling...
No more info on the web, but tubes are so small...
Some pic there:

http://www.hpr-powerboats.com/sale/

What do you know about that?

See post #11

That's probably what your talking about. It pulls the water out as it's being sucked up. I kinda dropped the ball on this after doing the hull pickup test and seeing literally no mph difference in having pickups and not having them. I will still test the rudder pickup when I finish the test boat for that. May be a couple months However. Doing a prop wash test is not something I'm planning anymore because the in hull pickups were so efficient.

[Fluid]

The biggest problem with sponson-bottom pickups in hydros is that a SAW Hydro at speed really floats over the water, so the mechanism for water pickup doesn't exist for much of the run. The Germans and some Americans who run big cats often use a pump system as the boat rests between passes to cool things down. It works well for them, but the efficiency depends on a low water temperature. In Summer and Fall water temps are higher, meaning you can't cool things lower than the pond temperature.

In recent years hydro record holders super-cool the motor and ESC buy pumping ice water through the cooling lines prior to the run. This drops the starting temps below 40*F; by the end of a couple passes the temps are lower than if conventional cooling was used. Plus the starting temps are lower so motor and ESC efficiencies are higher. But it does limit most boats to just two passes.

Bottom line, there are miltiple ways to get there. Just like most things FE.



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