Faster than the wind

[Leafy]

Thanks guys,

I’m now convinced that PM exist. I’m sure that it’s just a matter of time before it becomes a reality. We have our differences but we’re all here on PM forum and not mainstream forum. Hopefully I have no more reason to get excited about PM. Farewell.

[WaltzCee]

gravity acceleration like downwind one side and upwind the other , but our way to interact with gravity is through weight .

I added a silly diagram here ,it does not represent a mechanical design , it just represents a point , I think the forward push (I used thrust from a propeller for example) must be greater than the total drag induced , so that drag and thrust can cancel but enough push remains left over to prevent bearing friction from stopping the "pendulum" so it may cross over past 12 with velocity intact , however my idea was (if possible) to use drag force (air resistance) instead of propellers linked to wheels somehow... anyway its a long time ago and I dumped that idea because i could not figure out how.

Rather than a propeller, why can't the RKE of the wheels/weight be harvested to cause the wheel to go from an unbalanced state to a balanced one.

[WaltzCee]

I meant from a balanced to unbalanced then balanced, every 180°

[johannesbender]

yip a propeller would need some serious thrust , more thrust than total drag + total wheel and bearing and roll frictions + gearing frictions ,plus enough left over to push it across 12 with surplus , that's not happening :)

In and out of balance , yes the dream the glory the magic , however unattainable to us thus far or as far as I'm aware of ,by now I am so negative towards weight systems that attempt to move mass in and out for torque though , perhaps something else ...

Of course its not unattainable to have force/energy to rotate / move a wheel , that's easy , the problem is having force/energy to continue doing so , just like its easy using weights to do exactly that (as in rotate a wheel albeit not much) what moves the weights back...

[Tarsier79]

https://youtu.be/QTF5kw51H60

[WaltzCee]

It is cool

Доброго дня
Принцип работы:
Винт с самого начала служит тормозящим парашютом, из-за этого скорость вращения конструкции с калесом не соответствует скорости вращения нижнего ведущего диска,
колесо из-за этого набирает скорость и раскручивают винт ,
Но в начале совпадает по направлению движения с нижним диском.
Далее создаётся тяга достаточная для изменения направления движения всей верхней конструкции.
Если смотреть относительно нижнего диска, то при старте вращения нижнего диска скорость верхней конструкции сразу становится не равной ей, то есть отрицательной.
Далее винт набирает скорость, скорость машинки растёт, и в какой-то момент, наблюдателю кажется что скорость вращения становится равной нулю, А на самом деле скорость просто постоянно увеличивается отрицательно вращению диска

Have a nice day
Principle of operation:
The screw from the beginning serves as a braking parachute, because of this the speed of rotation of the structure with the wheel does not correspond to the speed of rotation of the lower drive disc,
The wheel therefore gains speed and unwinds the propeller,
But at the beginning coincides in the direction of movement with the lower disk.
Then it creates enough thrust to change the direction of the entire upper structure.
If you look relative to the lower disk, when you start spinning the lower disk, the speed of the upper structure immediately becomes unequal to it, that is, negative.
Then the screw gains speed, the speed of the machine grows, and at some point, it seems to the observer that the rotation speed becomes equal to zero, but in fact the speed just constantly increases negatively to the rotation of the disk

very cool

[johannesbender]

well , if you increased the arm length further out and placed the prop out there , you would increase the leverage from the point of thrust towards the wheel/weight/gear , however I guess since the velocity would be higher it means drag would be higher too .

[Fletcher]

Hey jb et al .. your 'prop on a stick' would work well if moving the prop on a vertical pendulum in still air was really OU.

Because the Lift Force is far greater than the cumulative Drag Forces in a rotation, if you have an efficient aerofoil.

Here's an animation of an old sim I made 17 years ago based on such an idea as yours - the "Drop-Wing" (sim slightly updated and included).

I had done at the time an extensive analysis of the America's Cup yachts and their VMGs - and it was faster than the wind IIRC. That lead me to DDWFTTW carts and the Blackbird etc etc.

It had me scratching my head about whether it could be OU - to be so it would have to work in still air and have excess KE/momentum. That seemed a bit of a stretch but worth an investigation and ultimately we simmed it and then built it over a period of about 18 mths.

Bottom lining it .. ground speeds are faster than the wind speed - given that stabilized speed is reached when total Drag forces equal Thrust Forces (equilibrium). But it wasn't possible in the real-world in STILL AIR (it needed the wind to BLOW).

The sim showed an excess impetus over tdc - it used standard industry equations for LIft and Drag forces e.g. used by NASA and in wind tunnel testing etc. The sim was one shot only because I couldn't design a ratchet to reset. Anyways your prop idea could also have a similar type of "pull-mech" or mesh-cogs etc.

ETA : the sim shows 2 parallel wings that Lift Force closes together when released. These forces (Lift (green) and Drag (red) are cloned in real time onto the disk wing shape to show its ability to pull the disk around thru the geared pull-mech and rod. That was to cope with 3D movement in x,y, and z plane at the same time.

...............

Last week I built a second Savonius wind-mill here at home - they are Drag type wind turbine i.e. no or little aerodynamic Lift. Therefore they can't over-rotate and can only rotate at the wind speed (good for exposed areas). The upshot being that 2 carts could be lined up on a salt lake - 1 with prop drive and 1 with a Flettner (Savonius) type drive https://en.wikipedia.org/wiki/Flettner_rotor i.e. drag only drive verses aerodynamic Bernoulli contribution to ground speed. I would say the Savonius type couldn't go above wind speed.

Anyhoo .. the sim investigation showed promise but the real-world build was a bit of a lame duck - reason being that there are about 5 main theories of flight, and they are all models - none are completely accurate but the best physicists and engineers can come up with. None imo are capable of producing OU except in sim-world like mine did.

When I get time I will put together a simple sim to show clearly what I mean when I say they can't be OU, with an example.




................

[johannesbender]

Yes Fletcher , one thing i have learned is the lesser the angle or time you have available to apply a force to , to boost a "pendulum" over the top , the more the force must be , at 180 degrees from 12 to 6 you are already down at half the circle which reduces the time and angle and increases the amount of force needed to apply from 12 to 6 to go over 12 from 6 to 12 , if you sim a simple pendulum just to see how much force is needed to reach 12 with full friction and resistance etc you will see how the energy requirements goes up for lets say half a circle and one quarter of a circle or 30 degrees of a circle etc.

ETA: This ties back to the normal OB designs too.

[johannesbender]

Do i think the cart design shown in the video and applied vertical could be ou or pm ? Never did , but i think it might perhaps be able to attain the same effect with gravity, thats why i made the drawing however i think a steaight vertical drop would be a better comparison, i cant say i believe that it would 100% work , i think it would take a high drop such that a cart would have plenty of time to accelerate and spin up the blades , but could it do so before terminal velocity , it would be interesting to see .

[Senax]

https://youtu.be/QTF5kw51H60

Interesting find. Thanks.

[Senax]

...
Bottom lining it .. ground speeds are faster than the wind speed - given that stabilized speed is reached when total Drag forces equal Thrust Forces (equilibrium). But it wasn't possible in the real-world in STILL AIR (it needed the wind to BLOW).
...

Quite so.
And for the BW to work it needs the Gravity wind to blow.
Fortunately in the real world it always blows.

[Fletcher]

Do i think the cart design shown in the video and applied vertical could be ou or pm ? Never did , but i think it might perhaps be able to attain the same effect with gravity, that's why i made the drawing however i think a straight vertical drop would be a better comparison, i cant say i believe that it would 100% work , i think it would take a high drop such that a cart would have plenty of time to accelerate and spin up the blades , but could it do so before terminal velocity , it would be interesting to see .

When I get time I will put together a simple sim to show clearly what I mean when I say they can't be OU, with an example.

I hope you find this sim interesting .. this is a do-over of a sim Rainer and I did way-back-when - it isn't encouraging as you will see. Two "wings" are dropped vertically in a gravity field - One is the very aerodynamic Gottingen profile (blue) and the other a red rectangle shape tho it could be a spear/triangle shape etc .. point is it has no aerodynamic features. They are for direct comparison of forces and force development.

Both Lift force and Drag force (equations) are functions of the Velocity squared relationship - the Lift force plot shows this best i.e. exponential increases/growth with velocity in Still Air conditions (which doesn't make any sense).

To check I plotted KE's of both at the same or similar vertical height lost. You can see how ridiculous it gets at a glance or follow the Outputs. Blue KE is orders of magnitude greater than the Red "Wing" KE ( mgh = m 1/2 v^2 .. or .. mgh = KE ) for a similar height loss.

The L & D equations work well in the linear wind testing tunnel situation - they are accurate predictors of forces etc. That doesn't translate to still air environment and free fall etc or rotating enviroment.

IOW's this proves to me that the L & D equations, altho they show the possibility of extracting OU or PM as a model of indicative behaviour they are just not accurate enough for all situations.

Fwiw .. I moved to Fiji in 2010 when the sims had been completed. Rainer and his model making friend built the "Drop Wing" and tested it etc. Mainly to humour me I think lol. I had to know whether it was a dead duck or had some life in it with a swift kick ;7)

Having been a former pilot I knew that when you put power on and raised the nose to climb attitude the climb rate did not keep increasing or go exponential etc - the airspeed steadied out and the climb rate stayed the same .. thrust = drag. That didn't deter me from investigations all-the-same.

This sim proved to me that the Laws of Thermodynamics held true. Nothing can be got from or for Nothing.




....................

[johannesbender]

Fletcher ,i see yes quite interesting ,as long as you have airflow from movement through the air and angle of attack (aoa) aren't past stall angle you dont need wind really blowing as wings can produce lift in still air if they have movement though.

Interesting that you managed to sim the wing on that trajectory because it would have flopped over without stabilizers and correct cog vs wing lift locations (joke) , ofcourse I imagine its a flying wing type of sim for simplicity , I can see it sims lift and drag properties of the profile , guess you simmed for a particular wing aspect ratio , I know how wing performance drops with scaling down to model sizes , i was scratch building a 2m fokker dvii (biplane) at one time and the upper main wing took me a few months but i would not settle for smaller , never finished her though.

Well all interesting , imo no wing would produce ou though.

Also that's me a little while after the cord was pulled, what's better than flying with nothing but earth underneath you and being able to freely view around you, but let me tell you free falling is a wild experience though haha :)

[Fletcher]

Fletcher ,i see yes quite interesting ,as long as you have airflow from movement through the air and angle of attack (aoa) aren't past stall angle you don't need wind really blowing as wings can produce lift in still air if they have movement though.

Yes, a plane or helicopter (lifting surface) can "glide" in still air conditions. We had a saying when trouble struck - "convert speed to height" to give you more time to sort out options. Worked well in the cruise, you could gain height but lost speed. I could never go from a glide configuration, pull up, and get the aircraft to gain more height than when I set up the glide for range.

Interesting that you managed to sim the wing on that trajectory because it would have flopped over without stabilizers and correct cog vs wing lift locations (joke) , of course I imagine its a flying wing type of sim for simplicity , I can see it sims lift and drag properties of the profile , guess you simmed for a particular wing aspect ratio , I know how wing performance drops with scaling down to model sizes , i was scratching building a 2m fokker dvii (biplane) at one time and the upper main wing took me a few months but i would not settle for smaller , never finished her though.

Well all interesting , imo no wing would produce ou though.

It was the Gottingen profile Coefficient of Lift 1.02 and Drag 0.003 (approx 34:1). The sim didn't flop or pivot coz I loaded the L & D forces at mid stations, with no torque. So aspect ratio wasn't required for the demo.

Yes, scaling is problematic in aerodynamics. Relatively speaking the smaller the wing the bigger the air molecules. A C Kermode "Mechanics of Flight" (instructor pilots bible) has a whole chapter on it and Reynolds numbers IIRC.

You should finish her - they are so much fun especially if radio controlled. Personally I'm waiting for the "Hoverbike" to become mainstream lol. That'll be a hoot.

Well all interesting , imo no wing would produce ou though.

Totally agree ! Still Air or Not !

It was a fun sim to build and investigation because the equations showed the gate was open even if in reality it was firmly closed lol.

But easy to see how the BB etc (or America's Cup Cats) can double or trebble the wind speed buoy to buoy. Just Low drag and big Thrust factors that eventually equalize at a ground speed or Velocity Made Good (VMG) greater than the wind speed

ETA .. LOL, that made me smile. Nothing like jumping out of a perfectly good plane. Done it once or twice. Novice only so no long free-falling but would love to do it again.