New Water Pickup Prototype

[riksorensen]

So here we go...
It is a new and hopefully improved way of feeding your FEs with a high PSI water flow for cooling....
Before I explain... Here is what I know...

• More PSI = More Flow
• Greter Tube Diameter = More Flow and Volume (Provided there are no bottlenecks in the design)
• Faster and greater flow volume = Better cooling
• A colder motor = More power and less energy consuption
• Air in cooling/water lines is not great

Anyway... so I JB welded a 5/32 brass tube to the back of my HK Genesis and wrapped it around and underneath...
It should offer awesome waterflow into the boat with very minimal extra drag as the tube is tucked behind the rudder..
Additionally, it should improve the flow of water over the rudder at it will now have a rounded trailing edge...
This is just to compliment and run parallel with the rudder internal water inlet...
I will be using both... The new mod for the motor and the other for the ESC...
Im not sure if I will put 90deg fittings on top of the rudder or leave it with direct nipples in parallel...

Just looking for some feedback...

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[Fluid]

The drag penalty probably outweighs any tiny increase in power. The drag will be greater than about any other water pickup design. Drag comes from the rounded back of the rudder and the large tubing sticking down at the thinnest part of the rudder. Too, handling would be affected on some hulls. A far better method is to incorporate flush pickups in the bottom of the sponsons - easier to do on flat-bottomed sponsons rather than the high-deadrise of the Genesis sponsons. Virtually no drag and at a high pressure pickup point.

If you were having cooling issues due to an inadequate water supply then maybe the big tubing mod will help, but inadequate water is not the usual cause of overheating - excess amp draw for the system is.


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[riksorensen]

A large part of the resistance of a rudder is created by the vortices, similar to miniature whirlpools that form when the water flows across the faces of the rudder building pressure on each side. As this pressurised water flows over the trailing edge of a common RC Boat rudder (square edge) it creates drag and turbulance. Ideally a rudder would be an elongated teardrop shape... In lieu of the original rudders fundamental design, rounding the trailing edge will reduce turbulance and thus reduce drag...
The tube in this design is .2mm narower than the rudders maximum width, not greter in any way. This addition rounds the trailing edge of the rudder in a perfect semi-circle.
I agree in part that "inadequate water is not the usual cause of overheating - and that excess amp draw for the system is." However, more water and less amp draw combined can increase performance per-se.

Attached is a rudimentary topographical diagram of the revised rudder design with subjective water flow analysis...
The third diagram would be a somewhat ideal rudder profile modification...
rudder hydrodynamics 1.jpg

[Fluid]

You have spent a lot of time trying to subjectively prove a fallacy. You are assuming that our rudders are somehow like "wings". While fully submerged rudders may have less drag with your ideal configuration, surface piercing rudders with a "streamlined" shape have significantly more drag and will cause handling issues due to the 'wandering effect' such a rudder produces. All the R/C boat record holders use wedge-shaped rudders, there is a reason for that. But don't believe me. Below is a technical paper which has been out for over a decade, peer reviewed, and still accepted. Re-invent the wheel if you want, I'm just trying to point you in the right direction.

http://rcboat.com/527_3.pdf


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[riksorensen]

You have spent a lot of time trying to subjectively prove a fallacy. You are assuming that our rudders are somehow like "wings". While fully submerged rudders may have less drag with your ideal configuration, surface piercing rudders with a "streamlined" shape have significantly more drag and will cause handling issues due to the 'wandering effect' such a rudder produces. All the R/C boat record holders use wedge-shaped rudders, there is a reason for that. But don't believe me. Below is a technical paper which has been out for over a decade, peer reviewed, and still accepted. Re-invent the wheel if you want, I'm just trying to point you in the right direction.

http://rcboat.com/527_3.pdf


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I stand humbly corrected and enthused at the theory and physics behind it...

I will re-mod the rudder with sharp square trailing edges and lean out the intake...

Thanks for the info!!!

Lovin it

[dasboata]

OMG your could of done a better job, have some pride in your work if you going to place a picture on the internet

[icelert]

P6250063.jpg

Nothing wrong with this rudder!

[JackBlack26]

The second to last picture shows the tube is off center. To someone with OCD, it drives me nuts!

Also, that was a good read, Fluid. Thanks for the link!

[riksorensen]

The second to last picture shows the tube is off center. To someone with OCD, it drives me nuts!

Also, that was a good read, Fluid. Thanks for the link!

I'm with you on the OCD

It has been modified even more, especially after fluids summation...

I will post pics tomorrow...

It now is centered and it tapered underneath as well as having a square trailing edge...

Stay tuned