Assembling the Gearbox Assembling： For installation, set 2mm screws to the front plate first. Assemble all the parts with a propeller and secure both end screws of the driveshaft. Check if it is spinning smoothly. Flat head screws of the post between the plate, should be secured at last. Balancing the propeller： Before balancing the propeller, remove the pinion gear or release the motor from the spur gear, so that the propeller can be spun freely. (It may be difficult, depending on the Airplane's structure.) 1) Set the gearbox with the propeller in position and ready for use. 2) Remove the pinion gear or release the motor. 3) Run the motor at low RPM to give some vibrations to the fuselage. 4) Then the propeller's off balance can be seen more apparently. (It may be difficult while the bearings are new, because of the viscosity of grease.) 5) Carefully balance the propeller. The test airplanes with the gearbox Masahiro Kadokura, as the leader of electric pattern flight in Japan, has been flying those two test airplanes equipped with the gearbox codeveloped with 50-Products. OK model Navigator 25 ARF that has been converted from gas to electric power. Battery: 10-cell 2400mAh Ni-cd Weight: 2000g.(4.41 lb.) Wing area: 30sq.dm.(456sq.in.) Motor: Speed 500 class, LT212 Gear ratio: 106:18 = 5.89:1 Prop: APC 12*8 RPM: 7500rpm. Experimental Funfly No 1. Battery: 7-cell 2400mAh Ni-cd Weight: 1080g.(2.38 lb.) Wing area: 33sq.dm.(501.6 sq.in.) Motor: Speed 500 class, L212 Gear ratio: 106:20 = 5.3:1 Prop: APC 13*6 RPM: 6800rpm.(initial) For sport flight, around 4:1 gear ratio is mostly used at present.The further stage of development is that more than 5:1 gear ratio would be necessary. Main reasons are as follows: １）　When the input wattage is the same, possibly larger diameter propeller would produce thrust more efficiently. ２）　When the motor size is the same, higher rpm would produce more power. Since the torque per revolution is limited, by the force of the magnet, the power is produced in proportion to the rpm, as it is the product of torque and rpm. It is not that simple in reality, but quite surely the higher rpm motor will be used, as the battery's improvement in the future. Sample installation.

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