The folks at Adam Aircraft don't particularly like it when their new airplane is referred to as a "push-pull," the most common (and cleanest) name attached to the Cessna Skymaster that made its debut about 40 years ago. The concept of centerline thrust, tandem power, was actually patented by Claudius Dornier in 1937 and developed during World War II.
Maybe "tandem twin" can be made to stick. Whatever, Adam Aircraft has created a twin built mostly of composites that looks back a bit but that is all new and optimizes the concept of the tandem twin, the power available and the current technology.
The airplane pictured and flown is the second Adam A500 built by the company. (Scaled Composites built an initial proof-of-concept airplane that looked similar but really wasn't.) The first Adam-built airplane has been retired to static test, and flight testing is continuing with this second airplane. A third airplane is now being built and may have flown by the time you read this. The third airplane will be the first to fully conform to production standards.
A lot of people have seen the Adam A500 at airshows, in a crowd. The airplane has a different personality when you see it alone, in a hangar or on a ramp. Everyone agrees that it looks bigger. It is. With a 44-foot span, 36.7 foot overall length and 9.5 foot height, it compares dimensionally with a Cessna 421 and is substantially larger than the four-seat Cessna Skymaster. The size is enhanced by the fact that it has more pieces than a conventional airplane. The booms are large and gracefully shaped as they arch up to the horizontal tail, which is high above the power pulses from the props. The tail is quite shapely and couldn't have been as nice had the airplane been made of metal.
The wings are nicely shaped, too, and have removable leading edges for access to control cables and TKS deicing components. The horizontal tail also has a removable leading edge. The TKS system was recently chosen as the ice protection for the airplane after Adam considered deice boots and other ice protection technology.
It apparently made more sense for the control surfaces to be metal, so they are. Different things affect designs in different ways because in transport airplanes a first move to composites has been in control surfaces.
The airplane I flew had a removable door with no hinges and no steps. It was not pressurized and may never be. It did not have nosewheel steering as the production airplane will have. Nor did it have cabin heating or much of an interior. The two seats installed, in the cockpit, were fixed, not adjustable. The airplane was being operated as an experimental, approved by the FAA for market survey work but restricted to day VFR conditions.
The two A500s have flown more than 200 hours, but there is much flight testing left to be done, and the FAA will want data from testing with the fully conforming third airplane. The airspeed envelope had been examined out to 180 knots indicated airspeed, which is well within the green arc on this particular airplane. Airspeed limits will be established in the final testing phase.
