to the simple shapes that Q500 planes are, which have much cleaner aerodynamics and less wing area. They use the same basic Nelson engine used in 428, but the engine is tuned to turn a much smaller prop at a much higher rpm. These planes can fly in excess of on the course. Because of their limited wing area however, Q40 planes must fly a larger arc around the pylons to conserve energy. Although faster, they ultimately fly a larger course. The best times for a 10 lap 3 pylon Q40 race are very close to the same in 428. F3D is the fastest class in "glow-powered" pylon racing. These planes reach speeds of over 100 m/s (225 mph) on the race course. The race course is the same as in AMA 424 or AMA 428, but there are few limits on the airframe and engine. The maximum engine displacement is .40ci, ignition must be a glowplug, fuel must be 80% methanol/20% castor oil, all else is free. There are airframe limits on wing thickness, fuselage dimensions, and weight for safety reasons. All this results in an extreme racing class, where R&D, trial and error, science, and piloting skills meet to create a very fast and exciting sport. Park flyers and micro planes Park flyers are small, primarily electric-powered planes, so named because their size enables some of them to be operated within the confines of a large public park. The smallest park flyers are called micro planes, and are slow and docile enough to fly within an enclosed area such as a gymnasium or even a living room. Because of their size and relative ease of setup, ready-to-fly park flyers are among the most popular class of RC aircraft for beginners and advanced pilots alike. Advanced electronic and material technologies have even brought forth high-performance, park flyer sized "3D-flyers", or fully aerobatic aircraft capable of extreme high g maneuvers and even nose-up hovering. Once the exclusive realm of giant scale, 3D flight is now possible both indoors and out with certain park flyer aircraft. Park flyers have created an inexpensive and convenient way for beginners to get involved in the hobby of RC flight. The modern materials used in the simple construction of these aircraft make field repairs possible even after significant crash damage. Their small size and quiet operation make it possible to fly them in residential areas.