Experimenter

October 2013

Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.

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The Sam LS courtesy of a classic heat muff; it is possible (though not official) on experimental versions to use coolant or even oil heat courtesy of the Rotax engine. same as the very large Diamond DA50 or Zenair STOL CH 850, all of which use big engines and carry at least twice as many people. (Note: A King Air 350's cabin—not cockpit—is 54 inches wide, including the aisle!) About That Tandem Cockpit Everybody knows that most people want to sit side by side in an airplane, but the tandem cockpit has some advantages, particularly in comfort and efficiency. First, efficiency: Not only does the cross section of a tandem cockpit allow a smaller fuselage frontal area, the added length of the fuselage can permit better ballistics and a proper taper to the tail. As for comfort, a relatively narrow fuselage is quite wide for a single person. (There is a minimum: The Rotax engine is 22.7 inches wide, after all; and it needs a little clearance.) To have shoulder room equivalent to that in the Sam, a sideby-side cockpit would have to be 52 inches wide—about the The cockpit layout is classic: center stick; the throttle, choke, and "mags" are on the left; the right side provides the perch for the trim position indicator; and on the floor on the right is the fuel tank selector valve. Aircraft systems and power information and typical primary flight display information are displayed front and center, on the 10-inch Dynon screen. Standby instruments— airspeed, altimeter, vertical speed, and turn coordinator—flank the Dynon, with the radio just below it. But ultimately for an airplane, it's about the flying, and for that, I rely on experts. Test pilot Rafael Langumier started his description of the walk-around (preflight) with this: "Starting from the cockpit, counterclockwise, the pilot can check everything easily. The hinges, rods, and connections are easy to check. The landing gear is very simple, and the fuel quantity can be checked visually and verified on the Dynon." Access to the engine oil reservoir also is easy, without the need to remove the upper engine cowling. Rafael also likes "the easy access to the cockpit provided by a step in front of the left wing." He said, "With my chute and my helmet I can be seated without contortions. Every control falls to hand in a comfortable and natural position so that the pilot can keep his right hand on the yoke and play with the Dynon or switches with the left hand, even during critical phases of flight (like the approach)." Te Sam's robust landing gear and step. Te gear can be encased in wheel pants for a sleeker look and a bit more airspeed. Rafael next went through the flight envelope, starting with normal phases of flight such as takeoff, climb, cruise, descent, approach, and landing. Takeoff on a cool windless day, without flaps, calls for rotation at 47 mph, and the Sam breaks ground at 53 mph; the takeoff run is under 400 feet. Rafael said, "I didn't find any difficulties in flying the Sam. The rudder needs a little pressure during the climb, but it disappears as speed increases, until in cruise, you don't need rudder pressure to keep the ball centered." Stick forces, he said, are similar to what "we should find on certified aircraft. For example, controlling the Sam on the lateral axis requires two pounds of pressure. For the pitch control, about three to four pounds are necessary. This gives the Sam a good control on the roll; the pitch control gives the pilot the ability to maintain altitude easily, and the electric trim is helpful so that the pilot can fly hands-off." Roll rate is demonstrated at 18 degrees/second. Construction of the Sam is simple and classic. Shown here are the wing attachment points. [Note: this was a ft-up only; washers are installed in actual assembly.] 24 Vol.2 No.10 / October 2013 Rafael conducted stalls and steep turn stalls. He said, "The Sam stalls without buffet warning; but the nose drops when Photography courtesy of Sam Aircraft

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