Performance Rotorcraft/Configurator Worksheet

[ptc-5479339]

Performance Rotorcraft

The perfornance rotorcraft mathcad worksheet asks for a minimum airfoil drag.

Is this in regards to the propeller and if so how is it calculated?

This worksheet calculates power consumption for forward flight, vertical climb, etc. However, it seems that the calculations are based around only one motor with one propeller lifting the entire vehicle takeoff weight.

On the multirotor there are six motors providing thrust to lift the entire vehicle weight.

[ptc-5237290 · Accepted solution]

The minimum drag or zero-lift drag (Cd0) is a characteristic of the airfoil. Each airfoil has a certain Cd0 value. Depending on the type of airfoil you select, you can look up the Cd0 value from standard published data e.g. few good sources of airfoil data are:

http://aerospace.illinois.edu/m-selig/ads/coord_database.html

http://airfoiltools.com/airfoil/naca4digit

A common airfoil is NACA 0012. It has a Cd0 of 0.008.

The calculations in the worksheet are based on one main rotor. If you have more than one main rotor (like in a multi-rotor configuration), same mechanism is used for calculations, the power required gets multiplied by the number of rotors.

Please feel free to let me know if you have any other questions.

Thanks

-Dr. Khalid

khalida1@erau.edu

[ptc-5479339]

Is the airfoil we are selecting meant to be the shape of the propeller blade?

Thanks

-Derek

[ptc-5237290]

Derek,

Note that a propeller blade can use any type of airfoil. Typically the twist distribution, taper ratio and prop size have a bigger impact on thrust and power than the type of airfoil used for rotorcraft blades.

Thanks

-Dr. Khalid