OT: Can a wind powered land craft go faster than a tail wind speed?...

[Rick C]

On Wednesday, December 22, 2021 at 9:31:03 PM UTC-4, Jasen Betts wrote:

On 2021-12-23, Rick C <gnuarm.del...@gmail.com> wrote:
Has anyone tested an upwind version?
I\'m faily sure it\'s been done.

I searched \"propeller car upwind\"; this was on the first page:

https://www.youtube.com/watch?v=F7PNSyAfCjk
If the wind is pushing it downwind the wheels will turn the prop in the opposite direction to go downwind.
Yeah but the gearing between the \"fan\" and the wheels is such that the
fan has machnical advantage over the wheels (for downwind the wheels
have the mechanical advantage). thus the \"propeller\" (actually impeller or turbine in this case)
turns the wheels driving the vehicle into the wind, and at the same
time increasing the amount of wind encountered.

It\'s not so much the gearing specifically, it\'s the prop pitch being almost feathered. This creates very little drag and the force downwind is very slight. So the force rotating the blades can move the car forward.

If the car is pushed upwind everything turns the right way, but how
does it get started?
The wind turns the propeller
Even then, I\'m not convinced the details work.
The only way I could make the idea work in my head for the downwind
car is to consider the gearing to turn the prop slower producing more
force than the force on the wheels to start the whole thing.
If you reverse that gear ratio I don\'t see how the thing can work.
The prop would exert less force because of the constant power through
the gear train.
Consider the case where 1000 turs of the propeller cause 1 rotation of
the axle, clearly it\'s at-least possible to travel upwind at some (low) speed

Only if the wind force on the prop (drag) is less than the force from the wheels. I see where this is possible. I suppose that once again, the speed is only limited by the losses in the system. This also shows the vehicle can be moving in any direction relative to the wind. Interesting. It would require a lot of phone and electric lines to be buried or raised, also streets widened. Tough to pass. lol

I wonder if that guy on eevblog has figured out any of this. He sure seems dead certain none of this works. He is invoking pressure storage of energy and claiming you can only go a short distance. At one point I was trying to get him to not say people were incorrect in talking about \"rate\" being a time factor in regards to power vs. energy and he completely refuses to understand. I got into the conversation and compared power:energy to speed:distance at which point he started talking about relativity... Really? Relativity???

--

Rick C.

-+- Get 1,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209