There are many answers for this question but none of them are specific. I need to find the exact relation between the lift force of a propeller of specific pitch, attack angle , dimensions and material with torque to be produced in a propeller at a specific speed at a certain altitude of a vertical take-off and landing aircraft to hover and fly forward. Can some experts in the field derive this relation.

  • $\begingroup$ Such details are often found in propeller maps, these relate prop beta, advance ratio, efficiency, power coefficient and static performance. This is propeller specific. $\endgroup$ – 0scar Mar 11 at 12:04
  • $\begingroup$ thanks for replying. And is there any webpage to find such propeller maps ? $\endgroup$ – Mohammed Siddique Mar 11 at 15:44

The relationship of torque produced by the engine and lift force will be the drag of the rotor. Increase in lift force by increasing rpm or AOA will require a proportional increase in power output from the engine. Air density also plays a role.

With a common helicopter, torque is counter balanced by increasing or decreasing torque of the tail rotor.

  • $\begingroup$ Thanks for replying @RobertDiGiovanni, Can you please put that into a formula considering all proportionality constants and what if an electric motor is used to drive the rotor? $\endgroup$ – Mohammed Siddique Mar 13 at 14:29
  • $\begingroup$ @Mohammed Siddique using an electric motor is a good idea. Starting on a small scale, power input, lift and torque are easily measured. $\endgroup$ – Robert DiGiovanni Mar 13 at 16:04
  • $\begingroup$ Well, I am designing a Motor and, i have calculated the Lift force to be produced by the rotor, i just need to figure out how much torque does my motor should produce to achieve that lift. Can you help me @RobertDiGiovanni. $\endgroup$ – Mohammed Siddique Mar 13 at 16:22
  • $\begingroup$ Not without knowing the lift/drag ratio of the airfoil you are using for your rotor. Depending on the drone, you may be able to "reverse engineer" from existing drones (at the hobby store). $\endgroup$ – Robert DiGiovanni Mar 13 at 20:43
  • $\begingroup$ How is lift/drag ratio depends on torque!? Can you explain me a little further. @RobertDiGiovanni $\endgroup$ – Mohammed Siddique Mar 18 at 8:23

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