A most elegant — and forgotten — Rutan-led design for a two-seat general aviation pusher...

The Scorpion team (minus , a.k.a. the "Mojave Eight": Oldham, Schirra, Mackerodt, Davisson (top row); Chrsitensen, McCandlish, Cole, Tristani (front row).

The PM Scorpion as it appeared on the cover of Popular Mechanics, cover date August 1987.

Customer:Popular Mechanics

Type: general aviation canard twin-pusher

Powerplant:2 x high-performance twin rotary engines

Significant date:1987

The Scorpion resulted from a project by the Popular Mechanics magazine to gather a think tank of experts to design "the Piper Cub for the next dozen generations." Gathered at Scaled Composites for a day, under the auspices of Burt Rutan, were Navy test pilot Wally Schirra, aviation entrepreneur Frank Christensen, commercial airline captain and former Navy test pilot J. P. Tristani, aviation illustrator Mark McCandlish, and the magazine's own journalist and pilot Fred Mackerodt, editor-in-chief Joe Oldham and Science/Technology/Aerospace editor Tim Cole.

All these experts hadn't come just to design a plane, but with the conviction that the aviation market was seen as ailing and their reflections might lead to a cure. The number of student starts had declined steadily, not to mention the number of new pilots who bought small planes. The appalling increase in the cost of flight instruction and training aircraft was part of the problem, as well as FAA certification costs and product liability insurance. The motto was to design an airplane of the future that would be "revolutionary instead of evolutionary", in other words, to start from a clean slate instead of relying on existing designs.

The guidelines set for the new design were as follows: a revolutionary design, to be an entry-level training platform removing all hardware barriers between flight and the average man on the street — the most user-friendly airplane ever designed. The team was unanimous that the aircraft had to be a two-seater. However, disagreement rose as to whether the seat should be arranged in tandem or side-by-side. Burt Rutan made the case for staggered seating instead, which presented many advantages: among these, it kept the fuselage narrow and gave both passenger and pilot plenty of elbow room.

Once the staggered seating was chosen, flight controls and the instrument panel were discussed. It was decided to opt for side-sticks for both pilots.As the instrument panel was seen as a major reason so many people don't learn to fly, the approach was to create a system that boiled down every single piece of important information to one visual display easy to decipher. The heart of the Scorpion's avionics would be a pair of inexpensive microprocessors. The displays wouldn't be numbers or figures, just simple graphic designs conveying all the necessary information. The fly-by-wire mentality that permeated the discussion was carried through to its logical conclusion when it was suggested to use fiber optic cast into the structure for primary control.

As soon as the discussion moved to the outside of the plane, both Rutan and McCandlish started sketching. The guidelines the group laid down for the design of the airframe structure were fairly simple: Keep the parts count low to aid in manufacturing and reduce expense. Keep it small, and make it a visual grabber. The propeller was tried on virtually every part of the plane. Finally, it was decided to put a pair of lightweight, inexpensive engines on the wing trailing edges, as close as possible to the fuselage to limit asymmetrical thrust with one engine operative. This cleaned up the nose of the airplane dramatically, and high-aspect ratio canards were fitted to help with stall and center of gravity control and to lower the parts count too.

The wings were given a modicum of forward sweep to allow the main spar to pass completely aft of the cabin area while keeping the wing's center of pressure located correctly in relation to the airplane's center of gravity. Because of the centerline landing gear arrangement chosen, negative dihedral was added to keep the wing tips close to the ground so that tip-dragger outrigger wheels could be fitted.

There wasn't much doubt that the Scorpion would be made of some sort of fiber synthetic. The primary goal was, once again, to keep the parts count and labor costs low. Frank Christensen opted for a skinned-foam process and others discussed ways in which integral structural parts could be molded in The airplane would be made in large sections, like a plastic model kit: Two halves for the fuselage, another two halves for the wing, etc.

In its blue-sky delirium, the group ignored product liability and other issues and concentrated on the machine itself. As Christensen pointed out: "All the things we've talked about are possible. The injection-molding concept for the airframe panels is here. Certainly, the electronics are easy. All that stuff is here in one form or another. The engines could be here soon." FAA certification would still be necessary and it would be expensive, as would be liability insurance.

Population: not built

Specifications: 200-mph top speed

Crew/passengers: 2


- "Wings for Tomorrow", Popular Mechanics, August 1987
- "Scorpion Revisited", Popular Mechanics, January 1988

Before the final configuration for the Scorpion was chosen, several configurations were considered. "Burt was frantiically producing the visions that raced through his mind—he averaged a new airframe design every 90 seconds."