Pylon turns (the RC type) – Sooner or later in every pylon racer’s career, this subject is discussed and dissected. And there are basically two types of pylon turns, the theoretical perfect turn, and then what most people actually do. First off, the airplanes in the fast classes of racing (428 Quickie), (422 Q-40), and (FAI) are very fast airplanes by modeling standards. The 428 can do around 170 mph, while the other two fill in the gaps to 200. So they are covering around 250-270 feet per second and would need very little top rudder to knife edge the length of the race course.

BUT, testing with radar shows that flying the entire race while in knife edge results in about a 5 mph penalty in top speed. While this might also result in the shortest distance, it is not typically the course flown by the top competitors. A faster path results in the airplane flying with a bank angle of around 45 –60 degrees, and then rolling to near vertical at the turns. Now any airplane that is trimmed for level flight when the wings are level will require a slight amount of up elevator when banked to this angle, resulting in a very large radius turn (around 1800 feet) while the airplane is loaded at about 1 ½ g’s. What this looks like in the air is the airplane come out of the tight turn at the pylon with the wings near vertical, and rolls out to the 50 degree bank. Because of the release point of the elevator and the big radius flown to the other end of the course, the airplane will move about 25 feet wide of a straight line path before returning to the next turn entry point. The pilot then rolls up to the vertical and does the next turn. Do this 20 times in about 1 minute, and you have just finished a heat.

WHY? When the airplane is in the vertical, pulling g’s, it is pulling around 30 to 40 g’s which causes a great deal of drag. To lower this drag, high aspect wings are now used within the limits of the rules. But another method of reducing this drag is to cut the turn short. So an event that looks to the causal observer to be 20 turns of 180 degrees is really 20 turns of about 166 degrees interspersed with 20 turns of about 14 degrees. Since less time is spent slowing down in the high g turns, the model is able to maintain a higher average speed. Now it is true that the airplane is flying a longer path, but the difference in length is rather small.

As far as the actual bank angle in the high g turns, is it 90 degrees? I use the turns to gain or lose altitude by banking less than 90 to gain, while overbanking to lose it. One must also remember that the course is very dynamic with three other airplanes trying to fly a similar path, with corrections for them as well as cross winds included.