W&B 4-3

Figure 4-2. CG of a trike. CG Aircraft CG • CG is under wing hang point for level flight. • Center of lift is directly above CG, above the wing hang point for level flight. Thrust line is typically designed to be at vertical CG. Fuel tank a Repairman: Light Sport certificate, and (in some cases) by their pilots and/or owners. Weight and Balance Aircraft such as balloons, powered parachutes, and WSC do not require weight and balance computations because the load is suspended below the lifting mechanism. The CG range in these types of aircraft is such that it is difficult to exceed CG limits. For example, the rear seat position and fuel of a WSC aircraft are as close as possible to the hang point with the aircraft in a suspended attitude. Thus, load variations have little effect on the CG. This also holds true for lighter-than- air aircraft, such as a balloon basket or gondola. While it is difficult to exceed CG limits in these aircraft, pilots should never overload an aircraft, as doing so may cause structural damage and/or failures. Weight affects performance; therefore, pilots should calculate weight and remain within the manufacturer’s established limits at all times. WSC Aircraft WSC aircraft are one- and two-place aircraft that exceed the criteria of an ultra-light vehicle but do meet the criteria of an LSA. The definition for WSC can be found in 14 CFR part 1. A WSC aircraft used for sport and private pilot flying must be registered with an FAA N-number, have an airworthiness certificate, a pilot’s operating handbook (POH), and/or limitations with a weight and loading document aboard. As mentioned earlier, WSC aircraft are commonly called trikes. These aircraft have few options for loading because they lack places to put useful load items. One-place trikes have only one seat and a fuel tank, which means the only variables for a flight are amount of fuel and weight of the pilot. Two-place trikes can accommodate a pilot and a passenger. This version may have a small storage bin in addition to the fuel tank. The most significant factor affecting the weight and balance of a trike is the weight of the pilot and, if the aircraft has two seats, the weight of the passenger. The trike acts somewhat like a single, main-rotor helicopter because the weight of the aircraft hangs like a pendulum under the wing. Figure 4-2 shows a two-place trike, in which the mast and the nose strut come together slightly below the wing attach point. When the trike is in flight, the weight of the aircraft hangs from the wing attach point. The weight of the engine and fuel is behind this point, the passenger is almost directly below this point, and the pilot is forward of this point. The balance of the aircraft is determined by how all these weights compare. The wing attach point, with respect to the wing keel, is an adjustable location. The attach point is moved slightly forward or slightly aft, depending on the weight of the occupants. For