Windmill or Wind Turbine- powered boats: how many are out there, and are they viable?

No they don't. A pushing prop is self stabiling so needs no support other than a tiny shaft. It has large forces causing it to align with the flow. I have pushed a boat over 15kph with an unstrutted prop on an 8mm diameter aluminium shaft that is 4ft long from the point of support. See the attached.

Rick W.

 

Rotary Sails and Man Powered Vehicles

(I use the word "man" as the short form of human. It has nothing to do with gender: male, female and etc.) Any sexists aboard?

General notes:

A self pitch adjusting Rotary Sail has much less drag in a gale force wind than can be expected from a bare mast and rigging.

The supporting mast should be mounted on a suitable axial mounting and balanced to the vehicle centre of pressure, i.e. over the centre of pressure of a keel or fin and midway on a land vehicle.

My Trailer-Tri, "Thrippence" had its rotor mounted on a car wheel hub with a drum brake to lock it in one position for maintenance.

The directional fin was mounted clear of the wind shadow of the rotor.

I left the rotor freewheeling in gales or when at anchor or ashore, it has little adverse drag and only turns at a moderate pace when idling.

The rotor must be easily disconnected from the drive.

Immediately a load is applied it begins to work and believe me, its a powerful beast if mis-handled.

A small high-speed rotor is powerful. Low cost blades need only be 9 inches or 0.3 meters in length for recreational craft, or nthey can be large enough for ship propulsion.

Blades made from carbon fiber or injection moulded plastic should have a flexible reflexed trailing edge.

Rotor blades can have an integral shaft with bearings mounted axially along the centre of pressure.

A small high-speed flywheel in a Hydrogen filled casing would be beneficial, but any form of flywheel regeneration will improve the utility of Rotary Sails.

Ripple-capping air lubricated boats have low drag and are easy to make.

Streamlining of the vehicle is important.

Study original Albert Hickman Sea Sled. (A fast row-boat.)

Happy experimenting. Cheers, Lin

 

ok call me walt vernes de la pancha but on windmills how about CR props in a savonius rotor
with a split but 100% frontal inlet, size of a radar or cooky tin and just to trickle the battery's

 

Hi Pete:
I think your video is just fine. I must have looked at it 7 times.
Richard

 

Hello Duma Tau My sentiments exactly, that why I go for Rotary Sails! Cheers, Lin

 

Hell Rick, I thought you were after performance as shown in your video of a sreamlined yellow crocodile. The craft show is a slow boat. Good fishing. Cheers, Lin

 

Hi Jehard:
You omly get gyroscopic effects with a self powered turbin such as a helicopterñç: but not with a passive system such as a windmill generator
or a gyroglider (which I built and flew).
Richard Miller

 

Hi Jehardiman:
You omly get gyroscopic effects with a self powered turbin such as a helicopter: but not with a passive system such as a windmill generator
or a gyroglider (which I built and flew).
Richard Miller

 

Hi Rayk:
I would like to echo Windmaster´s sentiments: I too have built 2 (1 meter) models and they both sailed directly into the wind (with less speed of course) but still made foreward progress at a practical pace.
Richard Miller

 

You missed the point. You will always have processional effects in 2 of the three axies depending on the axis of the rotor (maybe all 3 if you have a strange arrangement). Indeed, the effect was used in the Baden-Baden to reduce roll and pitch, and is still used in motion damping systems. The larger the mass inertia of the rotor, the larger the effect. Some small demo models have shown very pronounced effects.

 

John
I can vouch for the gyroscopic forces. I was supporting the thrust load on a 2.2m 2-bladed turbine in wind around 35kph (tip speed around 8X wind) and the reaction to positional change was substantial.

Rick W.

 

Are you talking about contra or counter rotating props?
http://en.wikipedia.org/wiki/Contra-rotating_propellers

http://en.wikipedia.org/wiki/Counter-rotating_propellers

 

Richard Miller

The site is on You-Tube. It takes a few mins. to surpass the speed of the wind but it does eventually get there.

 

Richard
I have played around with the idea a long time ago before I knew how to design blades with any precision. I did get a small model to progress into the wind. I now have quite good performance prediction methods based on proven propeller/turbine models and have made many high efficiency water blades and one set of high efficiency air blades. You will see in a earlier post that I am now working on electrically coupled air and water twisted foils.

The things that you need to understand.
1. Gearing. The system works because of gear ratio between the turbine and propeller. The turbine must be higher geared than the propeller. By gearing I am refering to the overall ratio that includes mechanical, electric or hydraulic connection and the pitch of the twisted foils. So if you have mechanical connected twisted foils with a ratio of 1:1 and you are going upwind then the air turbine will need a pitch of say 1m and the water propeller will need a pitch around 0.5m for a practical system. You might need to give the turbine a kick if the wind is light.

2. Efficiency. The required gear ratio is a function of the overall efficiency. The best result I can achieve is that the effective pitch of the turbine is 1.6X the propeller. However you need reasonably strong wind for this to work as the efficiency of the air turbine, of the size we are considering, is low at low Reynolds number. Also high aspect blades are more efficient than low aspect blades. Generally two or three bladed high aspects foils, as you see on modern wind turbines, will give the best result. You can get efficiences close to 90% for each twisted foil. My water twisted foils are similar in shape to air twisted foils as seen in the attached photos.

3. Upwind/Downwind. Upwind the air foil is the power collecter and the water foil is the propulsor. Downwind the air foil is the propulsor and the water foil is the power collector. For beam wind, the air foil is the collector and the water foil the propulsor.

4. Power Transfer. Nothing is free and the system losses result in greater power transfer within the system than the power required simply to propel the boat through the water. It means the propeller (air or water) is larger than required if you were not tapping power form the other medium.

5. Twisted Foil Interconnection. To get the best result from the system you need to be able to change the effective gearing between the foils. Going upwind the air turbine needs around twice the effective pitch of the water propeller. Downwind the situation is reversed. So you need to have mechanical adjustment of gearing through a selectable gearbox or pitch change. Modern electrics enable very wide change in gear ratio between the two foils through electronic controllers and this is the path I am going down. There are more components and associated losses but the system has advantages beyond the gearing aspect. It also allows simple power storage so when the wind is very strong you can store energy rather than depowering or waste energy trying to go faster. You can supplement power collection with solar cells and you can collect energy when moored.

If you want to have a go at building a system I can provide high efficiency blade design to suit your conditions. I would need to know some detail on the size and shape of the intended hull and the method of interconnecting.

Even a small (say 2m diameter) air turbine is a serious piece of machinery once windspeed builds. The tip velocity on a high efficiency blade will be around 8X windspeed so it has large kinetic energy even if built from lightweight materials. There are also substantial gyroscopic forces once it gets going.

Rick W.

 

If I may say so, you have'nt made this very clear. Talking about pitch you have got to say what diameter you are using. With a "twisted foil" pitch is obviously the best description, since the blade angle changes from root to tip. But I have found the turbine blades don't need to be twisted anyway so a simple angle is enough of a description.
Sorry - the term "twisted foil" is not a very good one since the air blades I use are not twisted - sorry to be pedantic!