The world's first seven-blade propeller has been installed on 75 Pilatus PC-12 aircraft across Europe and the US. The installation of the Silent 7 MT-Propeller sets new limits for certain applications, exceeding the performance of five-blade propellers.
The advantages of The Silent 7 are that certified take off performance is improved by 20 per cent with improved climb and cruise; there is a very low, jet-like level noise both in the cabin and outdoors; and it has very smooth operation.
The STC for the Pilatus PC-12 with the Silent 7 MT-Propeller meets the highest noise regulations in European countries for unrestricted airport operations.
In April 2023, the PC-12 STC combined with the seven-blade MTV-47 propeller was again updated to reflect the improvement in certified performance in the AFMS, reducing the required take off length by approximately 20 per cent compared to the original certified data. Already converted PC-12 aircraft can receive the latest certified performance range of MT propellers.
The company also manufactured its 100,000th blade in May 2023. Because of their natural composite construction, the blades are much lighter than aluminium propeller systems and have a higher vibration dampening coefficient compared to foam core composite blades. By this they also reduce vibration because the composite material does not support harmonics. No restricted rpm ranges, red bands for those blades on certified installations.
The blades have an unlimited blade life, because they can be brought back to the exact factory dimensions during overhaul. Even after a ground strike, the blade tips can be rebuilt to the new original dimensions. The first MT-Propeller blades, manufactured in 1981, are still in service.
Their light weight makes it possible to add more blades to a propeller system, which means that three-blade conversions, for example, can run more quietly than large two-blade systems, and in addition, smaller propeller arc disks have less drag than larger diameter propeller arc disks. Even seven-bladed propellers for turboprops are now available with lower loads on the engine during operation, compared to classic propeller systems.