Paddle wheel help

Re. paddles with disc sides; in this video at about 4 minutes is a boat with disc paddle wheels. Considering all its disadvantages (short fat hull, trimmed down by the stern, over immersed paddles, and the rudder consists of two discs either side of a rudder post at the bow) it goes very well.

On the other hand a parachute shape has a higher drag coefficient than a flat disc or rectangle so maybe the perfect "float" should be hemispherical or half round gutter section?

 

Lots of speculation.
Tests might be of a lot more help, and really help develop the boat quicker than just trials on a boat.

I had some friends build a human powered boat years ago.
Catamaran hulls, 4 bicycle riders as "motors", an 8' x 8' wheel at the stern (I don't know how deep the blades were), fixed blades.
From reports it went about 30 mph, was so fast eventually no competitors would show up.
It also sounded like a shotgun when each paddle entered the water.
Pretty extreme, but it worked well.

As has been said, you have too much wind drag and not enough paddle.

Surely there is some actual research to be found?

Good luck. As you can see, there is lots of interest.

Just another speculation, would an airfoil section work best?

 

Wow! That's fast, even for a bicycle on land.

 

In the video above there's an awful lot of water being raised up and flung away wastefully. If the wheels didn't have sides the water could have exited sideways as soon as the paddles left the water. It's obvious that by lifting water only to allow it to fall back with gravity is a waste of energy.

 

They don't have to be slow;
World's Fastest Paddlewheel Boat (Part 4) - YouTube

 

Kinda-sorta? Can't recall how this turned out.
Pedal Boat Design https://www.boatdesign.net/threads/pedal-boat-design.11932/

 

The ultimate high speed paddle wheel



To be made into a "boat" , perhaps a set of inflatable collars to keep it afloat when lift is lost.
A question that comes up would be " Would it be able to achieve planing if starting out in the water? Ie the collar placement to ensure a proper paddle depth


With this long track, the majority of the paddles are operating mainly horizontal with a low percentage of paddles (at a particular instance) either lifting water at exit or pushing water down at entry.

I would imagine that the paddles are between 2 to 3 inches.

Another query, is it possible to use this style of track propulsion between two hulls, with say 6 inch paddles?

 

This was a fascinating thread to follow, great online collaboration, and innovative work. I think life got in the way of realising a build in the end, but well worth a read.

 

Waste or counter productive? Thinking about the physics here. As long as the mass being ejected (water) is ejected towards the rear, it aids in forward propulsion. Water that spills out to the sides does not do that.

If you are losing water out the sides or creating non-directional turbulence around the submerged floats, then only the movement of mass at the rate of the turning wheel that is caught between float paddles will contribute to forward motion.

If, the mass that is being caught between the floats is directed by side covers to only ejected reward, then both mass and acceleration towards the rear would increase through centripetal force. The water in the center of the wheel would move outward to replace the water being lost by angular momentum like an impeller.

Maybe a good design would integrate hull form to guide water to the center of the side wheels and add its mass to the directed rearward thrust.

 

Seems like we're creeping up toward something that works like a Tesla turbine.

Cheers,

Earl

 

Bicycle speed record for one person is 183 mph, but some would consider it cheating the way it is done. But I don't see how anything similar could be done with a drag boat?

 

Will,
There was a reported 30' rooster tail when at full speed.
These were 4 dedicated road bike racers who provided power.
Moving as fast as they were they covered the course in a short time, so they could sprint.

 

I rebuilt the paddlewheels (doubled the paddles and made them deeper) I felt a definite difference in smooth operation but the speed seemed to stay the same. Right around 2mph if my app is to be believed. Here are some videos from out on the lake. Would love feedback from you guys

 

That is a very modest speed on the paddlewheel.
No real disturbance of the lake surface.
Can't be pushing much water.

Larger diameter and speed would help.

As I remember seeing Mississippi River paddlewheel boats, there was a lot of disturbance out the back of the wheel and the rpm on the wheel was much higher.

 

Allright, I like it.
Higher RPMs will get you going, if you get much bigger with the wheels it'll start to look funny.
Yes, larger diameter helps, but yours are big enough considering boat size.