thrust

Pete's Planes

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Thrust Lovely thrust. The more, the better.....Right? No.....wrong ! We often see thrust values quoted. Almost always these are for static thrust. It seems to be widely presumed that static thrust gives some indication of in-flight thrust. It does not. As soon as a model starts to move forward, its thrust reduces. As speed goes up, thrust comes down. At some forward speed thrust becomes zero. We can easily evaluate this zero-thrust speed (usually referred to as pitch speed), all we need is the propeller pitch and the static RPM.

Note that , no matter how high the static thrust, the in-flight thrust becomes zero when the aircraft flies at pitch speed.

For a given level of power, if you increase the gear ratio, you will increase the static thrust and reduce the pitch speed. [this assumes prop size adjusted, with same P/D] [ ratio = motor speed / prop speed]

Will model flyers ever take an interest in pitch speed, and forget about static thrust? I doubt it.