Links to competition classes

S9 Gyrocopter Duration

The fourth of the duration classes is in many ways the most challenging. Launched as a normal rocket at apogee the rotor blades are ejected from within the 40mm body tube and must unfurl and begin spinning to slow the decent of the model. The maximum time per flight is 180 seconds and, as with the other durarion classes the event is made up of three rounds, with the best cumulative score taking the gold medal.

Rotor blade design is key to this class. Short blades spin faster and make for a simpler design. Long blades, where they fold in half to fit in the rocket body, are the most popular at the moment. They are unfurled and held in place using the power of elastic bands. The blades are must usually made of balsa wood, although the British team are developing carbon fibre blades. By using carbon fibre a more consistant aerofoil can be acheived, ensuring equal lift from each rotor, and a perfectly balanced rotor head.

We have also been experimenting with some advanced aerofoil designs used on the new generation of wind turbines. The problem with these is that they spin so fast that they either "wind up" the model causing it to become unstable or they spin into the ground. Never the less this is a class in which there is much scope for R&D to build better models.