David First off range figures are VERY misleading. ANY aircraft can be shown to have a long range for its type if the engine is run slow enough and the basic tank large enough. MOST of the time you will find that max range figures are derived from an economy cruise setting of the engine, at an altitude of usually at least 8000 feet, with a combination or even a cruise prop for best performance that way, in single engine fixed pitch prop planes. This test flight is NOT done at max cruise speed, which yields quite different results as many pilots have found out over the years. In the case of the Corvair, if you pull it back to say 50% power, around 1800-2000 rpms, and fly along at 85 to 90 knots, then you should be burning 3 to 4 gallons an hour based on the information gathered from Joe Horton and Mark Langford and Bill Clapp when they fly. Flying faster costs more, from their numbers 70 to 75% power is closer to 5 to 6 gallons an hour, and pushing it up to near full power is closer to 7 to 8 gallons and hour. Once in the air at altitude, although there are alot of factors, at the risk of over simplifying, your range then becomes a math calculation of how long you will be able to fly, fuel on board, how fast, and what your groundspeed is. The higher the farther you will go in most cases (disregarding differences in wind at different altitudes).
As far as changing the spar goes, check the archives for information on the effects of longer wings; there have been LOTS of discussions on this. Then you will need to consult some good engineering/aviation design software. Lengthening the spar without making it larger in the middle sounds to me like asking for trouble, BUT I am not an engineer, so consult the software and those who know for answers BEFORE cutting any wood. The Dan Diehl wings skins is the longest I have heard of the wings being without modification, and it does not effect the original spar. The new wing requires the spar to be taller, but not longer... Colin Rainey First National Mortgage Sources Lending Solutions in All 50 States 386-673-6814 office 407-739-0834 cell brokerpilot9...@earthlink.net
