How much effort to lift a human being?

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    Human Lift
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Discussion Overview

The discussion centers around the theoretical considerations for lifting a 180 lb person using a propeller system, specifically focusing on the size of the propeller and the power requirements of the motor needed to achieve this lift consistently. The scope includes mechanical principles related to flight mechanics and static thrust calculations.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant queries the size of the propeller and the motor power required to lift a 180 lb person 30 ft into the air consistently.
  • Another participant suggests that the inquiry may relate to building a specific type of lifting device, though this is not confirmed.
  • A participant clarifies that they are interested in a theoretical approach using a two-bladed propeller.
  • One participant recommends using a "static thrust calculator" to determine the appropriate sizes of propellers and motors.
  • A later reply references mechanics of helicopter flight, providing equations for induced velocity and power needed for lift, along with an example involving a small helicopter's mass and rotor diameter.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the specific propeller size or motor power needed, and multiple approaches and suggestions are presented without resolution.

Contextual Notes

The discussion includes assumptions about air density and the mechanics of flight, which are not fully explored or defined. The calculations presented depend on specific conditions that may not be universally applicable.

Quinton Powell
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What size propeller is required to lift a 180 lb person 30ft into the air consistently? Also, how powerful would the motor have to be to lift itself, the propeller, and person?
 
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Are you trying to build something like this:
SafetyDropDevice1799664Diagrams-500px.jpg
 
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Not quite. I am looking for a 2 bladed prop. This is a theoretical question at this stage.
 
I think you can google "static thrust calculator" and find what size of propellers and motors are available.
 
From the Wikipedia page on mechanics of helicopter flight:

For stationary flight, out of ground effect, and for a helicopter weight F

cdd56de2fb1d84301b85a40a64a5f08a.png
where
f7f177957cf064a93e9811df8fe65ed1.png
is the air density.
The induced velocity needed for lift will be:

c156e32e0ff208f5a8d8e08077c3f67b.png

and the power (called induced power) :

37f0f92dbf516491e96abca115e01ac8.png
.
For example, in the case of a small helicopter of 700 kg mass and a rotor diameter of 7 m:

aa19a1fb9f74bc6fabff04d9edff75ae.png


= 60 kW = 80 hp

.
 

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