Wind Power Vehicle Traveling Down Wind Faster Than The Wind

AI Thread Summary
The discussion centers on the feasibility of a wind-powered vehicle traveling faster than the wind itself, a concept known as Directly Downwind Faster Than The Wind (DDWFTTW). Participants share insights on past experiments, including a full-scale model that achieved notable speeds, and debate the mechanics involved in achieving such speeds, particularly when moving at angles to the wind. The conversation highlights the theoretical underpinnings of the vehicle's propulsion system, which utilizes wheels to drive a propeller for downwind travel and a turbine for upwind movement. Additionally, there is a focus on the efficiency of these systems and the potential for future developments in wind-powered vehicle design. Overall, the thread emphasizes ongoing interest and research in this area of physics and engineering.
  • #301
chingel said:
I mean extra energy compared to when the propeller is not spinning. When you engage the propeller, the wind also works on the propeller blade that is turning.
When you engage the propeller the wheels also start braking. To get any "extra energy" by engaging the propeller you have to multiply the wheel force, to get a greater prop thrust. It's the net force resulting from the gearing that determines if you accelerate (gain energy).
 
Physics news on Phys.org
  • #302
Unless I missed it, I do not see mention of the, different energy rate changes, as speeds increase.
Wind energy to the turbine will be a cube factor.
Friction losses to body and frame parts increase by a square factor.
The KE of all things that are in motion, increase exponentially.

I looked at the rules (just a quick look) and all energy storage methods are ruled out, but could the transmission system be electric ? Wheel generators, sending electric energy straight to a motor in the turbine ?

Ron
 
  • #303
RonL said:
The KE of all things that are in motion, increase exponentially.

It raises as the square of the velocity. I don't think that's technically "exponentially".

I looked at the rules (just a quick look) and all energy storage methods are ruled out, but could the transmission system be electric ?

I don't recall whether the current rules allow it, but we've certainly discussed that approach. I think it's fine as long as we demonstrate that we have no way of accelerating by using stored energy.
 
  • #304
RonL said:
Unless I missed it, I do not see mention of the, different energy rate changes, as speeds increase.
Wind energy to the turbine will be a cube factor.
Friction losses to body and frame parts increase by a square factor.
The KE of all things that are in motion, increase exponentially.

I looked at the rules (just a quick look) and all energy storage methods are ruled out, but could the transmission system be electric ? Wheel generators, sending electric energy straight to a motor in the turbine ?

Ron

Just to nitpick, the first half appears to be talking about the upwind turbine cart, but then you talk about putting the motor on the turbine and the generators on the wheels, which would be the reverse of what you would want to do with the upwind cart.
 
  • #305
Llyricist said:
Just to nitpick, the first half appears to be talking about the upwind turbine cart, but then you talk about putting the motor on the turbine and the generators on the wheels, which would be the reverse of what you would want to do with the upwind cart.

:biggrin: I am going to need to back off a little, this where I start getting in trouble. This is an area that starts over lapping into electric aviation possibilities in my mind.
You are correct,...but if...
Motor/generator actions can be switched almost instantly changing which and where resistance is lost or applied, as energy,... does this give some amount of micro tweaking of that leverage effect mentioned before?

Ron
 
  • #306
RonL said:
Motor/generator actions can be switched almost instantly changing which and where resistance is lost or applied, as energy,... does this give some amount of micro tweaking of that leverage effect mentioned before?

I don't think so. The most we can ask of the transmission is to transmit the power with as near as possible 100% efficiency. The leverage we take advantage of comes from the difference in velocity between surface and air.
 
Back
Top