>Firstly, at altitude your MTOW is always going to be reduced over the MSL >maximum. Extending the wings may well compensate for that, but then you are >going to get a higher drag, requiring more HP to overcome it. Peter Bancks. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Your max takeoff weight is reduced only if you don't have enough POWER to drag the aircraft into the air. Longer wings should help the climb rate and the penalty for the longer wings will be felt primarily in the cruise mode and is probably not more than a few miles per hour. Larry Flesner (CONTINUED BELOW) +++++++++++++++++++++++++++++++++++++++++++++ >Secondly, and of greater concern, the higher altitude will also affect the >level of control authority, so while you may well get off the ground on that >hot day at your high altitude strip with a moderate load, you may find that >you lack sufficient elevator authority to get out of ground effect, and even >though you may have sufficient lift from your wing extensions, and power up >the yazoo from your turbo'ed engine, you are still going to trip over the >boundary fence because you are stuck in ground effect. >It's overcoming that ground effect that is going to be the reall isue for >you, not the horsepower of your engine. >Peter Bancks. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ It would appear to me that you have some misunderstandings on aircraft performance at higher altitudes. I would hope you clear them up before flying your KR. The single most important factor affecting performance at altitude is POWER. At 6000 feet you've lost 6 inchs of manifold pressure and a considerable percentage of the POWER output. When flying jumpers to 10,000 feet I can watch the manifold pressure drop with altitude. Starting at 30 inches at takeoff and dropping to 20 inches at 10,000 feet. I'm guessing I've lost more then 33 percent of my power. The airplane, however, flies just fine, even with 3 jumpers hanging out on the wing strut. My KR flies exactly the same at 6000 feet wheather I'm climbing with full power or decending at idle. Aircraft control with the control surfaces (rudder, elevator, ailerons) is a non-issue. The reason you hear of aircraft not being able to climb out of ground effect is again related to POWER. Ground effect is generally the distance of 1/2 the wingspan above the ground where the wing is much more efficent. It takes less POWER to fly the aircraft in ground effect. You can get youself into a situation where you can take off and fly in ground effect but can't climb above that because you don't have the POWER. Climbing out of ground effect has nothing to do with elevator authority but rather with the ability of the engine to generate enough POWER to pull the wing through the air at a speed that generates enough lift to climb. If you want better performance at altitude you need either more POWER or less weight so you don't need more POWER. Larry Flesner
