Design



		Design Performance Objectives The Jefferson Jyrodyne™ will offer significant improvements in safety, maintenance costs, and speeds over the VTOL aircraft available today, and it will do a better job of it than any other of the VTOL designs currently under development. The prototype is a slow, simple trainer that is similar in concept to the Cessna 150 or J3 Cub.

		Safer Operations The helicopter flight envelope had major areas in it where failure of the engine will result in an uncontrolled crash when autorotation cannot be implemented in time. The Jefferson Jyrodyne™ design will not have any areas in its flight envelope where a single engine failure will result in an uncontrolled crash. The VTOL propulsion is enclosed, so there are no rotor or tail boom strikes possible under any flight conditions.
		Reduced Maintenance Costs Helicopters have many limited life, expensively machines and heat-treated components, which must be replaced after only 1000 hours of flight. Vibration and fatigue is a serious and continual problem because of the inherent design. The Jefferson Jyrodyne™ design utilizes off-the-shelf industrial components and will circumvent the short life of the helicopter components by operating as a conventional aircraft during most of its mission hours as an aircraft.

		Higher Speeds Since the Jefferson Jyrodyne™ can operate as a conventional aircraft; it has none of the theoretical forward speed limitations so true of the helicopter or other rotorcraft. It is possible to eventually build a supersonic Jefferson Jyrodyne™.

The Jefferson Jyrodyne™ has a large rotor mounted horizontally inside a shrouded duct in the center of the fuselage. There is a tractor propeller mounted above and behind the shrouded duct. The drivetrain contains two engines, and two clutches. Both engines drive a common driveshaft. The clutches are located along the driveshaft, with one transferring power to the tractor propeller, and one to the horizontal rotor. For vertical takeoff, the power is transferred to the horizontal rotor. Once airborne, the Jyrodyne is tilted forward, which causes it to move forward. At about 30 mph, the wings will support the aircraft, and the power is then transferred to the tractor propeller. The Jyrodyne then flies like a conventional aircraft.


			The photo on the left shows part of the drivetrain. The two clutches are shown in the center. The tractor propellor clutch and sprocket is on the right, with the clutch for the rotor on the left.





On the right, is the part of the drivetrain not shown in the first photo. A 90° bevel gearbox is located on the right, with a special device called a “Flexidyne” located on the left. It mates to the large rubber coupling shown at the left in the first photograph.

The Jefferson Jyrodyne has multiple lifting surfaces:

A canard at the front of the aircraft A lower biplane wing with flaps An upper biplane wing with ailerons A full span elevator, divided into three sections During VTOL operations, positive lift from the front quadrant of the bellmouth shroud During transition operations, positive lift from the front quadrant of the bellmouth shroud, and no lift from the inboard sections of the upper biplane wing

The combined effect of all of these lifting surfaces provides unprecedented aerodynamic control to the pilot.

				The Jefferson Jyrodyne's™ mechanical components are all industrial or aircraft grade. The drive sprockets are hard anodized aluminum, containing steel or stainless steel Sprague clutches or multidisk clutches. Drive belts are Kevlar-reinforced. The bearing and gears are Timken, mounted in CNC-ed aluminum copies of Dodge pillow blocks. Thrust bearings are double row tapered roller bearings. The gears in the aluminum housed bevel gearbox are Timken spur gears. Couplings utilize high strength polyurethane male inserts in matched female connectors. The keyed driveshafts are 7075-T6 and 6061-T6 where needed.


	[right picture] 4 blade tractor propeller sprocket, driveshaft, bearings and mounting assembly

The Jefferson Jyrodyne™ structural analysis used finite element analysis for most of the design work of main aluminum structures, and also the composite parts. Some of the larger models took several hours to run, and many combinations of loads were evaluated. The structure shown in the drawing above is that of the passenger fuselage part of a single seat version.




This drawing is of the composite bellmouth for the ducted fan shroud.




While the Jefferson Jyrodyne™ will fit in a “Tee” hangar, it requires a slightly modified Tee hangar similar to those used for floatplanes. The first hangar was also subjected to detailed stress analysis prior to construction.