Wow, this almost to new humberism level, but not quite. There is no tailwind at the propeller, unless you are actually using that term as a pilot would. In which case, absolutely right, and it is that tailwind and the reduced power requirement because of it, that enables the cart to work.
When the wind is not following a ddw path, there is always a component of the wind that can power the cart. That is the basis of all fttw sailing.
That component is not within a ddw claim, no matter how you try and turn it on its head. That wind will be incident upon the propeller, and can affect its performance to the detriment of benefit of the cart. It is to the benefit as all charts show. The highest rates of acceleration are when the wind is not ddw.
Forces are frame invariant, as is rotational power.
Blah...blah... you are not in a position to make edicts concerning frames of reference, and the existence of angular motion rules out inertial frames.
It is a complex topic, that is more than simple-minded "thought experiments" of "backwards" roads.
And the F is the same in all frames.
For our purposes, Newton holds. If they were differences of force between frames, that would not be the case.
The cart experiences force F, as a result of the headwind. That is met via the wheel, by the same force at
the ground, and so power is F*Vcart.
It is quite clear that if you dip your hand into a river, the force against it is related to the velocity of the water relative to the bank. The work required to walk along the river bank while doing so, is related to that force, and hand's velocity relative to the bank. Same with the cart and the headwind.
The power is provided by thrust from the prop, and that drag power must come from it directly, and not just the force derived as you and Spork have incorrectly done.
Fault this, or concede.
F_Drag = K*Vhead^2
Power_Drag = K*Vhead^3
Pcart = K*Vhead^2*Vcart.
Yep, it's just too bad that the drag the airfoil sections produce always leave them with a net force pointing to the rear. And I have done the polars for those airfoils, and I know this for a fact.
Total nonsense, and you are far from being an aerodynamicist.
On the one hand, you make the claim that the prop gains energy from the wind, but somehow want to ignore the fact that it spends half of its time in wind that considerably faster than recorded. Simple exponential gradients do not apply in variable winds.
The vane shows that the wind is constantly and very rapidly, changing. There will be air currents in 3 dimensions, and the cart can exploit both horizontal and vertical gradients. A balloon in such winds would be seen to rise and fall in response to the vertical gradients.
You can assert this all you want, but until you can actually explain it, it remains fantasy.
I don't need to, because the burden of proof is upon the claimant. Why else would trials have been necessary? But, the trial data shows that the cart is better when not ddw, and NALSA's Steve Smith thinks crosswinds and gradients may be power the cart.
The cart's ddw math fails, and that is why you are trying to introduce spurious claims to cover the holes. Working the data is no substitute for a failed theory, and may no stand on its own.
There is no turbine torque above wind speed. only the power demand of the prop.
Then no tailwind at all. Good. That leaves you with no power source, but any lateral component from the incident wind can power the cart. If there is incident wind from the rear, which is certainly the case as the wind data shows, its effect on the turbine will be less than if the cart were ddw or
closer to ddw. The turbine force will fall as the cart moves away from ddw.
The power is related to cos^3 of the angle, and will be zero at 90 degrees. The lift force on the cart will increase, as the opposing turbine force falls.
That isn't the part that was wrong.
So far, bluff denial.
The record run clearly shows the cart's acceleration falling as the cart enters the record window. The acceleration levels are too small to be accurately recorded by the GT31, but what data there is, by no means shows that the cart is better ddw.
The acceleration data is derived from the GPS speed, and that has been shifted via filtering and/or other means, so that the drop in wind speed may be exploited. The wind changes later on in the window than is indicated by the acceleration derived from the cart's speed or other data averaged to match.
There is another Lycossys instrument that has improved capacities for measuring acceleration. The changes are extensive.
GT32-50 is a new instrument that combines GPS-Doppler with inertial navigation technology and magnetometer to enhance measurement of motion. GT32 contains two GPS-Doppler engines and 3-axis alias-free DC accelerometer sampling at 50Hz (providing 150 acceleration samples per second), all logging to SD card in compact binary format.
GT32 has evolved from GT31 and can be described as "9 instruments in one", all fitting into a single GT31 case and sharing one SD card. In essence, an additional hardware module has been fitted inside GT31 to extend its capabilities. This extra module comprises an autonomous gps-Doppler engine, three DC accelerometers 3D magnetic compass and a thermometer.
GT32 is aimed for people who want to measure jumps and acrobatics or carry multiple GT31 units in their effort to improve motion measurement accuracy. GT32 is cheaper and more compact than two GT31 instruments. In addition, GT32 offers possibilities that are beyond reach of a pair of GT31 units, such as higher bandwidth and detection of angular orientation (yaw, pitch, roll angles) of a moving craft, or in sport for example.
