Some of the key benefits of turbo-props over the more mainstream turbo-fans will be discussed, including; reduced fuel consumption, reduced exhaust emissions and lower operational costs. Furthermore, for military purposes in particular, the thrust available allows take off and landing on a much shorter runway/airstrip than a turbo-fan aircraft would be able to achieve.

The key design considerations for composite propeller blades will be explored. These include high strength to weight ratio, high fatigue resistance and damage tolerance. A composite blade also offers the significant advantage of being largely repairable where a metal blade may have to be replaced. As a primary structure of the aircraft, no fatigue or other structural failure is permissible. Composite blades are subject to stringent certification to evaluate the structural integrity, the detail of which will be outlined. Dowty Propellers are responsible for this certification and testing of the propeller, much of which is done in-house.

The composite blade manufacture involves a number of different materials and techniques. The processes explored include dry-fibre preforming of carbon and glass fibre, polyurethane foam injection, over-braiding and resin transfer moulding (RTM).

New areas for growth will be outlined, including un-ducted fans, as well as a discussion on potential new markets. Furthermore, developments in materials and processing will be explored with a view to future automated composite propeller manufacture.