Quote:
Originally Posted by Harri Pihl
Yes, and that is what I have been saying all the time.
What I do is that I convert the power (W) to the force (T) according to propeller efficiency (n) and speed (V):
T=(n*W)/V
And your failure is that you don't understand that this means that the force (thrust) varies with speed at constant power. Lets quote the Hamilton Standard Red book:
As I have explained my knowledge, and noted that the Hamilton Standard Blue Book has the same equation on page 109, as well as explained what it really calculates, perhaps you can answer my questions now? |
Harri - you have been very evasive about zero Velocity Thrust as well as explaining why the 'practical' approach to calculating high Hp/low velocity thrust equation doesn't work... or more to the point what is missing from the Trust discussion.
Could you please answer the questions?
Why the Thp equation breaks down at low speeds
What the Real Thrust of the Engine/Propeller system is at zero Velocity and max power is comprised of.
Is there a propeller drag at zero velocity?
Does propeller drag increase as freestream flow increases
Does exhaust Thrust increase or decrease or remain the same, with increases to velocity of the freestream?
If exhaust thrust remains the same at all speeds, where did you incorporate that in your Force balance equations for Cdi and Cdo = Thrust
Is Thrust Net Thrust (Total Thrust - Propeller Drag) or Total Thrust in the Thp equation.
What is your approach to calculate Thrust, or Net Thrust, or??, if different, and how does your 'new' approach work at both high speed, low speed and zero velocity?