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Buddy Trainer connectors

Have you ever wondered what pins are used on the Buddy Trainer connectors?

Trainer Plug Pinout Diagrams
( From Back Side)

Futaba Square

5 Pin Din

5 Pin Din
(Ground on Shield)

6 Pin Din
(Ground on Shield)

6 Pin Din

7 Pin Din
(Ground on Shield)



4 Pin Mini Din 

Aircraft Center of Gravity

Enter the variables at left using the same units for all entries.
    For an aircraft to be stable in pitch, its CG must be forward of the
    Neutral Point NP by a safety factor called the Static Margin, which
    is a percentage of the MAC (Mean Aerodynamic Chord).
    Static Margin should be between 5% and 15% for a good stability.

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Choosing The Correct Prop For Electric Motor




MOTOR LIMITS THAT ARE NOT TO BE EXCEEDED; these are given by the manufacturer and they are:


  1. Current.
  2. Wattage.
  3. Maximum RPM of the motor.


Selecting a prop is determined by considering;

  1. Wattage limits of the motor,
  2. Revs per volt of the motor,
  3. Current limit of the motor,
  4. A relationship between Watts, RPM and Prop sizes,
  5. What is to be expected of the aircraft, and,
  6. The formula W (Watts) = V (Volts) Multiplied by I (Amps)


For example if the motor power specification is 400 watts at maximum of 40 amps and the shaft speed is 2,000 revs/volt, the voltage required to use the motor at maximum power and current simultaneously is determined using the formula transposed as V=W/I and dividing the 400 watts by 40 amps, giving 10 volts. Ten volts determines the RPM of the motor at 20,000 RPM Referring to a prop/power chart, a prop size in the vicinity of 7 by 4 is required to absorb 400 watts of power at 20,000 RPM. This may be OK for a small fast flying aircraft but be unsuitable for other aircraft.


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Flight Checklist

Flight Checklist


Weight and balance

Is the model too heavy?

Is the center of gravity within the range shown on the plans?

Is the model balanced side to side? (right and left wings of equal weight)



Are all flying surfaces at the proper angle relative to each other?

Are there any twists in the wings? (other than designed-in washin or washout)

Control surfaces Are they all securely attached? (i.e. hinges glued, not just pushed in) Are the control throws in the proper direction and amount? (usually indicated in the plans) Control linkage Have all linkages been checked to make sure they are secure? Are all snap-links closed? Have snap-links been used on the servo end? (They are more likely to come loose when used on the servo)


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