The actual structural design of the Lear Fan is conventional, with parts made from graphite composite instead of metal. The wing has the usual spars and ribs, and inside the fuselage are the normal stringers and longerons. Everything is black instead of teen zinc chromate primer color that adorns the aluminum inside traditional airplanes. The Lear Fan is held together by adhesives, so no rivets mar the perfectly smooth surfaces.
Controls and systems in the Lear Fan are conventional, with purely mechanical flight control actuation. Although the horizontal tail is shaped like a V. its control surfaces are not ruddervators, as found on the Bonanza, but simply elevators.
Cabin measurements of the Lear Fan are about the same as those of a 90 Series King Air, although the Lear Fan baggage area is not as convenient to reach. Standard seating is for six passengers and two crewmembers. There is to be a private lavatory and refreshment center.
Projected Lear Fan performance is no less than spectacular, with a maximum cruise speed of 350 knots expected. In an engine-out situation, without asymmetric thrust or the drag of a dead engine and the displaced rudder needed to fly a straight line, Lear Fan engineers expect a 1,400fpm single-engine rate of climb, and a single-engine service ceiling of 29,000 feet.
A Lear Fan's fuel efficiency should be phenomenal, too, if weight goals are met. At maximum gross weight the airplane is projected to cruise at 300 knots for 1,800 nm with reserves, obtaining about eight nm per gallon. No turbine-powered airplane can come close in fuel efficiency. None of this performance comes cheap. Its present $1.6 million price tag will be escalated with inflation between order and delivery; that base price is expected to climb again soon. Initial purchasers got their orders at $850,000 with no inflation escalator.
For all its promise and accomplishments so far, however, the Lear Fan is only beginning. The entire FAA certification process is ahead, and, given the current climate within the FAA, it will be tough for the Lear Fan to stay on schedule for fall 1982 deliveries. The second preproduction aircraft won't be completed before this summer. Two complete aircraft must be built and then tested to their structural limits to demonstrate the strength of the airframe.
The Lear Fan will be certificated under the same FAR Part 23 rules that govern any piston or turboprop airplane weighing less than 12,500 pounds. - No airplane that relies heavily on graphite composites has yet been certificated, so the task of demonstrating the strength and durability of the material falls totally on the Lear Fan. The FAA attitude, LearAvia people say, is positive, but there are many questions. The graphite composite material is impervious to corrosion, but -what are the effects of sun, moisture and lightning strikes?
Graphite composite does not flex, so fatigue is not a problem. But are there other wearing and aging factors? Nobody knows for sure. Conventional radio antennas will not work on a nonmetallic surface and the effects of precipitation static on a nonconductive airframe- are not fully understood. And certificating a turboprop to Flight Level 410 will be a new experience for everyone. -
It's easy to look at the Lear Fan now and imagine all the hurdles ahead. But for Moya Lear, J.S. "Torch" Lewis, the vice president, and the others who have been at LearAvia from the start, it is much easier to look back and see how far they have come: to look at the half-full glass rather than the one that's half empty. That's the way Bill Lear would have looked at it, anyway.