Sunday, 21 November 2010

Modifications from the Balsa USA Stearman kit

The Stearmans are built from Balsa USA kits but have had some modifications to make them lighter and more detailed.

Holes have been laser cut in the fuselage formers, the tailplane, fin and wing wherever possible.  This reduces the weight which is especially important in these models because the rig and wingwalker add quite a lot of weight. 

To get the best performance we need to keep the weight as low as we can, whilst not compromising the strength of the structure.

The tailplane was made removable to make the planes easier to transport.  Both planes are transported in one van so they take up less space with the tailplanes off. Carbon fibre tubes are used to join the tailplane.  Elevator servos are in each half of tailplane

The Breitling team use Super Stearmans which have more flying wires than the Stearman so extra mounting points were fitted to attach the additional flying wires.  Hard mounting points also had to be added to attach the wingwalker's rig.

The spar size in the wing was reduced by half and webbing used to make the wing as light and strong as possible. The square aluminium tubes in the kit were replaced with round ones and are not glued in.  That way they are easy to remove so make transportation easier.

To match the full size planes that the models are based on top ailerons have been fitted and the bottom ailerons reduced slightly.  There are several configurations of top ailerons across all 4 planes that are either finished or in construction.  Some top ailerons are nearly the same size as the bottome ones and others are smaller. These reflect the full size configurations.

The nose has been shortened so the prop hub is in the correct line. A completely new cowl was made and starts from the cabane struts. On the full size the cowling was a modified Beech.  New wheel spats were made to the correct shape and a new spinner was made.  The spinner on the Super Stearman is a Harvard.

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