Paddle wheel help

Discussion in 'Boat Design' started by G4s1198, Dec 6, 2021.

  1. alan craig
    Joined: Jul 2012
    Posts: 340
    Likes: 106, Points: 53, Legacy Rep: 14
    Location: s.e. england

    alan craig Senior Member

    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?
     
    Will Gilmore likes this.
  2. upchurchmr
    Joined: Feb 2011
    Posts: 3,275
    Likes: 252, Points: 83, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    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. :D

    Just another speculation, would an airfoil section work best?
     
  3. Will Gilmore
    Joined: Aug 2017
    Posts: 766
    Likes: 319, Points: 63
    Location: Littleton, nh

    Will Gilmore Senior Member

    Wow! That's fast, even for a bicycle on land.
     
    portacruise likes this.
  4. Andrew Kirk
    Joined: Jul 2021
    Posts: 56
    Likes: 41, Points: 18
    Location: Chorley UK

    Andrew Kirk Pedal boater.

    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.
     
  5. rangebowdrie
    Joined: Nov 2009
    Posts: 162
    Likes: 60, Points: 28, Legacy Rep: 10
    Location: Oregon

    rangebowdrie Senior Member

  6. clmanges
    Joined: Jul 2008
    Posts: 529
    Likes: 110, Points: 43, Legacy Rep: 32
    Location: Ohio

    clmanges Senior Member

    Tiny Turnip likes this.
  7. Barry
    Joined: Mar 2002
    Posts: 1,647
    Likes: 372, Points: 83, Legacy Rep: 158

    Barry Senior Member

    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?
     
    Last edited: Dec 17, 2021
    fallguy, DogCavalry and hoytedow like this.
  8. Tiny Turnip
    Joined: Mar 2008
    Posts: 815
    Likes: 244, Points: 43, Legacy Rep: 743
    Location: Huddersfield, UK

    Tiny Turnip Senior Member

  9. Will Gilmore
    Joined: Aug 2017
    Posts: 766
    Likes: 319, Points: 63
    Location: Littleton, nh

    Will Gilmore Senior Member

    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.
     
  10. Earl Boebert
    Joined: Dec 2005
    Posts: 391
    Likes: 62, Points: 28, Legacy Rep: 302
    Location: Albuquerque NM USA

    Earl Boebert Senior Member

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

    Cheers,

    Earl
     
  11. portacruise
    Joined: Jun 2009
    Posts: 1,339
    Likes: 125, Points: 63, Legacy Rep: 218
    Location: USA

    portacruise Senior Member

    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?

     
  12. upchurchmr
    Joined: Feb 2011
    Posts: 3,275
    Likes: 252, Points: 83, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    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.
     
  13. G4s1198
    Joined: Feb 2020
    Posts: 23
    Likes: 2, Points: 3
    Location: Nj

    G4s1198 Junior Member

    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
     

    Attached Files:

  14. upchurchmr
    Joined: Feb 2011
    Posts: 3,275
    Likes: 252, Points: 83, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    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.
     

  15. rangebowdrie
    Joined: Nov 2009
    Posts: 162
    Likes: 60, Points: 28, Legacy Rep: 10
    Location: Oregon

    rangebowdrie Senior Member

    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.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.