30 August 2017
+VIDEO Why would you locate the engine of a light aircraft on top of the wing instead of in the conventional position on the nose? Well, according to Italian designer Alfredo di Cesare, there are at least six good reasons why he has done just that on his latest aircraft, the JetFox FX1.
This isn’t Alfredo’s first aircraft with the engine mounted above the wing. His first was the JetFox 91, built in 1991, which sold 160 units. Then the JetFox 97 in, er, 1997, which also sold well with 180 aircraft sold. They were followed in 2005 by the JetFox GT, which was also available as a floatplane.
So, the JetFox FX1 is the fourth generation aircraft from Alfredo’s company, InnovAviation, based on Italy’s east coast. It has been engineered to take advantage of all the lessons learned from the earlier aircraft and optimised using computer-aided design (CAD).
Those six reasons to mount the engine high:
1 Improved forward visibility No prop or bulky engine cowling to obstruct the view.
2 Comfortable cabin with less noise and vibration. With the exhaust pipe above the wing, the FX1 is also quieter for people on the ground.
3 Accelerated Lift & Control Response. With the propeller close to the wing, it directs accelerated airflow over the wing (‘accelerated lift’, a phenomenon common to twin engine designs), enhancing take-off performance. This effect also tames departure stall characteristics, contributing to the FX1’s forgiving flight qualities. In a similar way, the propeller is also closer to the vertical and horizontal stabilizers and associated control surfaces (rudder & elevators) for enhanced control response.
4 Centre of Gravity & Balance. As with mid-ship engine placement common for exotic sports cars, the FX1’s engine mass is closer to the aircraft’s centre of gravity, decreasing the aircraft’s moment of inertia for faster response in the pitch & yaw axes. For the roll axis, raising the engine to the level of the wings on a high-wing design increases roll response.
5 Safety In the event of a nose-first accident (as most are), the forward impact is transmitted to the airframe. The FX1 cockpit is surrounded by a cage of welded steel-alloy tubes wrapped in a carbon-fibre structure of strength and rigidity. In aircraft with the engine in the conventional position, the impact is taken by the engine which can then move backwards.
6 Ready for floats Another advantage of the FX1’s engine location applies to the float-plane application, where the engine and propeller are located far above the water, allowing the FX1 to serve as a very capable amphibian.
InnovAviation
2 comments
Good job.
Do you have plans for building it