So what’s under that huge nacelle located between the twin fuselages that make up the Pipistrel Taurus 4? A lot! Starting with the cog-belt propeller speed reduction unit that’s mated to the water-cooled electric motor, behind and below this we find the aluminum radiator nested in the large end of a carbon-fiber P-51 style belly scoop. Above the radiator is the sophisticated motor controller (and above that is the coolant expansion tank), and located behind all this is a large ballistic parachute. Remember, this is a four-place ship, and it’s not very light.
Although the intake side of the radiator cooling plenum is reminiscent of those found on the North American P-51 (noted for exploiting the “Meredith effect,” in which heated air exited the radiator as a form of jet thrust), the outlet side of the radiator on the Pipistrel does not have any form of a plenum and will not benefit as it could if it were completely modeled after the P-51.
Viewed from the trailing edge of the huge plain flap and looking forward, we find a fiberglass battery tray that houses nine of the lithium-ion battery cells. To the right of the battery tray is a very robust electric linear actuator that’s used to operate the full-span flap previously mentioned.
As the second technician started installing battery cells, he found it easier to disconnect the flap and let it hang down, giving him better access to the battery tray.
Installing the second of nine battery cells.
The ship, as delivered to AirVenture, is intended to be solely operated by the starboard passenger compartment, with passengers only in the port side, similar to the way that those sitting in the back seat of a four-seater don’t have access to controlling the plane.
The Pipistrel Taurus 4 is a planned competitor in the upcoming $1.65 million CAFE/NASA Green Flight Challenge, slated for the last week in September 2011.