On Wednesday, December 22, 2021 at 8:01:02 AM UTC-4, Jasen Betts wrote:
> On 2021-12-21, Rick C <gnuarm.del...@gmail.com> wrote:
> > On Tuesday, December 21, 2021 at 5:57:31 AM UTC-4, David Brown wrote:
> >> On 21/12/2021 02:44, Rick C wrote:
> >> > I say yes. I haven't watched the video, but looking at the
> >> > contraption and seeing how it would work says to me that it can
> >> > indeed go faster than the wind without tacking.
> >> >
> >> > https://www.youtube.com/watch?v=jyQwgBAaBag
> >> >
> >> > I didn't shorten the URL to avoid the wrath of sed.
> >> >
> >> > I recall watching a scene in a sci-fi show where they were flying a
> >> > solar wind powered craft. They talked about the high speeds they
> >> > could achieve as if they were tacking or something, but unless they
> >> > had invented an æther rudder, they were smoking wacky weed.
> >> >
> >> I believe the force of the wind on a propeller works in much the same
> >> way as on the sail of a boat that is tacking. If that is correct, a
> >> propeller based car can go faster than the wind, precisely because it
> >> /is/ tacking - even when the car is going in a straight line.
> >>
> >> It is also possible for a propeller powered car to run directly into the
> >> wind.
> >
> > You might actually give that one a bit of thought. Look at the two cars and consider the detailed forces and how they are generated. I think you will find it's the same car and always goes downwind, just with more or less efficiency, i.e. forwards or backwards.
> If you change the gearing so the propeller/impeller screws into the wind faster than
> the wheels work against the ground it will go upwind. If you set it lower
> than the wheels, downwind.

Has anyone tested an upwind version? If the wind is pushing it downwind the wheels will turn the prop in the opposite direction to go downwind. If the car is pushed upwind everything turns the right way, but how does it get started? 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.

--

Rick C.

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On 2021-12-23, Rick C <gnuarm.deletethisbit@gmail.com> wrote:
> On Wednesday, December 22, 2021 at 8:01:02 AM UTC-4, Jasen Betts wrote:
>> On 2021-12-21, Rick C <gnuarm.del...@gmail.com> wrote:
>> > On Tuesday, December 21, 2021 at 5:57:31 AM UTC-4, David Brown wrote:
>> >> On 21/12/2021 02:44, Rick C wrote:
>> >> > I say yes. I haven't watched the video, but looking at the
>> >> > contraption and seeing how it would work says to me that it can
>> >> > indeed go faster than the wind without tacking.
>> >> >
>> >> > https://www.youtube.com/watch?v=jyQwgBAaBag
>> >> >
>> >> > I didn't shorten the URL to avoid the wrath of sed.
>> >> >
>> >> > I recall watching a scene in a sci-fi show where they were flying a
>> >> > solar wind powered craft. They talked about the high speeds they
>> >> > could achieve as if they were tacking or something, but unless they
>> >> > had invented an æther rudder, they were smoking wacky weed.
>> >> >
>> >> I believe the force of the wind on a propeller works in much the same
>> >> way as on the sail of a boat that is tacking. If that is correct, a
>> >> propeller based car can go faster than the wind, precisely because it
>> >> /is/ tacking - even when the car is going in a straight line.
>> >>
>> >> It is also possible for a propeller powered car to run directly into the
>> >> wind.
>> >
>> > You might actually give that one a bit of thought. Look at the two cars and consider the detailed forces and how they are generated. I think you will find it's the same car and always goes downwind, just with more or less efficiency, i.e. forwards or backwards.
>> If you change the gearing so the propeller/impeller screws into the wind faster than
>> the wheels work against the ground it will go upwind. If you set it lower
>> than the wheels, downwind.
>
> 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.

> 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

Now think aboput it this way, there is some gear ratio where the converted
propeller torque exactly matches the axle torque, with this gear ratio the
vehicle is immune to the wind and doesn't need a parking brake. you can
push or pull on the front of the car and only feel the friction (and
innertia), not the wind.

If the ratio is increased the axle torque produced by the propeller is
insuficient to hold the car stationary and it travels down wind with a
mechanical assist from the wheels driving the propeller

If the ratio is reduced instead, the propeller now drives the wheels
and the car travels upwind, with a wind enhancement due to its
direction of travel.

Ideal shapes for impellers and propellers are similar but probably not
the same, but there is presumably some compromise shape that can travel
in both directions given suitable gear ratios (or perhaps adjusatable
blade pitch).

--
Jasen.

On 2021-12-23, Rick C <gnuarm.deletethisbit@gmail.com> wrote:
> On Wednesday, December 22, 2021 at 8:01:02 AM UTC-4, Jasen Betts wrote:
>> On 2021-12-21, Rick C <gnuarm.del...@gmail.com> wrote:
>> > On Tuesday, December 21, 2021 at 5:57:31 AM UTC-4, David Brown wrote:
>> >> On 21/12/2021 02:44, Rick C wrote:
>> >> > I say yes. I haven't watched the video, but looking at the
>> >> > contraption and seeing how it would work says to me that it can
>> >> > indeed go faster than the wind without tacking.
>> >> >
>> >> > https://www.youtube.com/watch?v=jyQwgBAaBag
>> >> >
>> >> > I didn't shorten the URL to avoid the wrath of sed.
>> >> >
>> >> > I recall watching a scene in a sci-fi show where they were flying a
>> >> > solar wind powered craft. They talked about the high speeds they
>> >> > could achieve as if they were tacking or something, but unless they
>> >> > had invented an æther rudder, they were smoking wacky weed.
>> >> >
>> >> I believe the force of the wind on a propeller works in much the same
>> >> way as on the sail of a boat that is tacking. If that is correct, a
>> >> propeller based car can go faster than the wind, precisely because it
>> >> /is/ tacking - even when the car is going in a straight line.
>> >>
>> >> It is also possible for a propeller powered car to run directly into the
>> >> wind.
>> >
>> > You might actually give that one a bit of thought. Look at the two cars and consider the detailed forces and how they are generated. I think you will find it's the same car and always goes downwind, just with more or less efficiency, i.e. forwards or backwards.
>> If you change the gearing so the propeller/impeller screws into the wind faster than
>> the wheels work against the ground it will go upwind. If you set it lower
>> than the wheels, downwind.
>
> 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.

> 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

Now think about it this way, the wind blows on the propeller and
creates a torque in the propeller shaft and also a force on the
vehicle, the force on the vehicle creates a torque in the wheel axles.
There is some gear ratio where the converted propeller torque exactly
matches the axle torque, with this gear ratio the vehicle is immune to
the wind and doesn't need a parking brake. you can push or pull on the
front of the car and only feel the friction (and innertia), not the wind.

If the ratio is increased the axle torque produced by the propeller is
insuficient to hold the car stationary and it travels down wind with a
mechanical assist from the wheels driving the propeller

If the ratio is reduced instead, the propeller now drives the wheels
and the car travels upwind, with a wind enhancement due to its
direction of travel.

Ideal shapes for impellers and propellers are similar but probably not
the same, but there is presumably some compromise shape that can travel
in both directions given suitable gear ratios (or perhaps adjusatable
blade pitch).

--
Jasen.

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