Reference Library

Under construction

Technical deep dives

Paul Martin on props, motors, etc.

• tbd

• tbd

Batteries

TBD: https://www.facebook.com/photo/?fbid=4847037825319536&set=g.668143127181552

Motors

• Brushless Motor Fundamentals

• Motor mass, size, and waste heat

• Stator laminations: Without super thin stator lams, efficiency suffers at high RPMs. Since thin stator lams are expensive, cheap motors (e.g. Freerchobby) use 0.35mm lams. Eddy losses in the iron stator core induced by the magnetic field switching as the rotor magnets fly past are proportional to the square of the lamination thickness x the square of the rpm. This explains why motors with thick stator lams generate excessive heat without going any faster. One notable exception is the inexpensive Turnigy Rotomax 150 which uses 0.2mm lams.

Props

• Paul Martin’s documentation

• 4th root equation

• Dr. Raynor’s equation

• eCalcs

Calculators

Motor

• Static thrust and horsepower

  • https://www.poweredparagliders.com.au/Calculators/Static_Thrust_Calculator.htm

  • http://www.csgnetwork.com/directhpthrustcalc.html

  • https://rcplanes.online/calc_thrust.htm

Formulas

• Kv(v) = RPM

• max kw - (.30) = max continuous power

• Motor efficiency: Used power - heat. Heat is P=i squared * amps (resistance squared times amps)

Propeller

• Prop pitch recommendation (for cruise?) based on RPM, airspeed, and prop length. You can also view the tables

• Theoretical speed

• Propeller Tip Speed Calculator

• Mejzlik calculators for disk loading, dynamic thrust, static thrust

Aviation

• NASA’s calculator for Cl, Cd, Drag, L/D (applet)

• Climb angle

• Glide distance, ratio, angles, trajectory

• Over 50 Aviation Converters and Calculators

Entire power train

• e-calc calculator

Metals

https://www.onlinemetals.com/en/weight-calculator

Flying strategies

• Best climb angle and speed

  • Flying, energy, power

  • Related forum discussion

Materials

Carbon fiber vs Aluminum