Le Magicien d'Oz

("the Wizard of Oz")


As you probably know, an ounce (symbol: oz) is a mass unit still used by some tribes who have not enjoyed the international metric system yet. One ounce approximately equals 28,35 grammes (Nota: there is another variety, the Troy ounce, which also approximately equals 31,10 grammes and could allow some modellers to play with mass measurements...).

Twenty-eight grammes, did you say? It is less than 31 grammes (of course...), Miss Daisy's mass, the mini-Indoor from the Dutch Rick Ruijsink. Nothing more was needed for the now well known "Twisteuse French team" (J.M. Piednoir, G. Jumelin et J.Y. Martin) to decide to go down below this magic number.


Magic? Ounce? oz? The name was then obvious, it will be "Le Magicien d'Oz" ("The Wizard of Oz") and the specification very simple: a mass of 28 grammes and a wing loading of 3 g/dm2 to be a slow-flyer. Why 3 g/dm2? Very simple! Because 3 g/dm2 equals 1 oz/sq.ft (another barbaric unit used by the same tribes). A "Magicien d'Oz" to the power 2 in a way...



Obviously, you have to keep it light! The fuselage is a triangular beam (30x20 mm measured at the leading edge) made of 3 carbon rods (diameter 1mm). Almost everything else is lamellated, that is to say 3 layers of 5/10 mm balsa and 2 layers of carbon tissue. The frame (fuselage, leading gear, wing, control surfaces) weighs 10 grammes. The receiver, the speed-controller and the two actuators are all home-made and weigh 5 grammes total. The motor (HS80 servo motor) weighs 2 grammes and is fed by 2 NiCd 50 mAh cells and a DC/DC converter (2,2V to 5,5V).

Mass analysis:

Technical data:

  • Completed wing: 3,5 g
  • Elevator: 1,3 g
  • Rudder: 0,7 g
  • Sub-total for wing and control surf.: 5,5 g
  • Fuselage: 3,4 g
  • Gear + 2 wheels: 1,1 g
  • Sub-total for fuselage: 4,5 g
  • Motor and gearbox 1/6,6: 3,3 g
  • Prop. 145x70: 1,2 g
  • Sub-total for motorisation: 4,5 g
  • ESC JMP: 0,2 g
  • Rx FM 41 MHz with quartz: 1,9 g
  • 2 servos (actuators): 2 g
  • Control links: 0,3 g
  • DC/DC converter: 1,6 g
  • 2X50 mAh battery: 7,6 g
  • Sub-total for radio: 13,6 g


Magicien d'Oz


G. Jumelin, J.M. Piednoir, J.Y. Martin



Wing span (mm):


Length (mm):


Wing area (dm2):


Mass (g):


Mass (oz)


Wing loading (g/dm2):


Wing loading (oz/sq.ft)



HS80 servo








JMP-France special

NiCd battery:

2x50 mAh


TOTAL 28,1 g

  • Structure, receiver and servos: 14,2 g
  • Motorisation, speed controller and battery: 13,9 g

The Wizard of Oz has been described by Dick Miller in Flying Models (May, 1999 issue).

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