I've been looking at the sport pilot standard. To be a light sport aircraft you have to meet the following criteria for an airplane since its original certification:
1) Max takeoff weight 1320 pounds (600 kg) 2) Max airspeed in level flight with maximum continuous power (VH) of not more than 120 knots CAS under standard atmospheric conditions at sea level. 3) Max stalling speed or minimum steady flight speed without the use of lift-enhancing devices (VS1) of not more than 45 knots CAS at the aircraft's maximum certificated takeoff weight and most critical center of gravity. 4) a maximum seating capacity of no more than two persons, including the pilot 5) a single, reciprocating engine, if powered 6) a fixed or ground-adjustable propellor 7) a nonpressurized cabin, if equipped with a cabin 8) fixed landing gear The only criteria that are not obviously passed (with the fixed gear version) are the VH and VS1. VS1 45 knots translates to 51.785 mph. the RR website says the KR2 and 2S stall at 52. My calculations indicate 51.5 for 900 pounds using a CL value of 1.7. (The CL value was computed based on weight, wing areas, and stall speeds posted on the RR website.) At a gross weight of 1050 lbs, Bill Marcy computed a stall speed of 59.1 mph based on a maximum lift coefficient of 1.454 for the RAF48 airfoil. The new airfoils have a CLmax value between 1.15 and 1.28 (http://www.krnet.org/as504x/design.html). The old airfoil has an advantage of a higher CLmax translating to a lower stall speed. Can anyone confirm that their plane will actually fly at the 45 knot limit? VH Many posts have stated the 200 mph number RR publishes is unrealistic and a few indicating it is possible to reach 200 with a big engine and lots of drag reduction. Can we get some actual numbers from people flying behind VW engines? I expect the Corvair and O-200 planes probably have too much power to be limited to 120 knots. If your plane does meet light sport aircraft spec with a VW, installing a Corvair and finding out you fly too fast would permanently remove you from the LSA category even if you reinstalled a VW. -- wesley scott k...@spottedowl.biz
