W&B 4-4

Figure 4-3. Wing attach point. Front collar Trike mast Keel nose plate Control frame apex Distance from nose plate to front edge of front collar Rear collar adjusted to eliminate gap when pivot block assembly is against front collar 501/2" to 521/2" example, if the aircraft is flown by a heavy person, the attach point can be moved farther aft, bringing the wing forward to compensate for the change in CG. Figure 4-3 shows a close- up of the wing attach point and the small amount of forward and aft movement that is available. Similar to airplanes, sailplanes, and powered parachutes, increasing weight creates increases in speed and descent rate. However, the WSC aircraft has a unique characteristic. Adding weight to a WSC aircraft creates more twist in the wing because the outboard leading edges flex more. With less lift at the tips, a nose-up effect is created and the trim speed lowers. Therefore, adding weight can increase speed similar to other aircraft, but reduce the trim speed because of the increased twist unique to the WSC aircraft. Each manufacturer’s make/model has different effects depending on the specific design. For detailed weight and balance information, characteristics, and operating limitations, always reference the specific manufacturer’s manual or POH for the make and model. Figure 4-4 shows an example of a weight and loading sheet that would be issued with a WSC aircraft. Every aircraft has its own weight and loading data that should come from the manufacturer. The example in Figure 4-4 comes from Airborne, an Australian company, named Airborne XT WSC aircraft. For additional information, refer to the Weight-Shift Control Aircraft Flying Handbook (FAA-H-8083-5). Powered Parachutes Powered parachutes have many of the same characteristics as WSC aircraft when it comes to weight and balance. They have the same limited loading, with only one or two seats, and a fuel tank. A powered parachute acts like a pendulum with the weight of the aircraft hanging beneath the inflated wing (parachute). The point at which the inflated wing attaches to the structure of the aircraft is adjustable to compensate for pilots and passengers of varying weights. With a very heavy pilot, the wing attach point would be moved forward to prevent the aircraft from being too nose heavy. Figure 4-5 illustrates the structure of a powered parachute and the location of the wing attachment. A powered parachute used for sport and private flying must be registered with an FAA N-number, have an airworthiness certificate, a POH, and/or limitations with a weight and balance document aboard. The aircraft must be maintained properly by the aircraft owner, or other qualified personnel, and have the aircraft logbooks available for inspection. Always refer to the POH for weight and balance information specifi to the powered parachute being fl wn. For additional information, refer to the Powered Parachute Flying Handbook (FAA-H-8083-29). Weight and Balance Computations (Amateur-Built Aircraft) A good weight and balance calculation is the keystone of flight testing an amateur-built aircraft. Accurately determining the aircraft’s takeoff weight and ensuring that the CG is within the aircraft’s design for each flight is critical to conducting a safe flight test The aircraft should be level when weighed, spanwise and fore and aft in accordance with the kit manufacturer’s instructions, and should be in the level flight position. It is highly recommended that the aircraft be weighed in an enclosed area using three calibrated scales. Bathroom scales are not recommended because they are not always accurate.