I'd heard that there was a real difference in the glide ratio of a plane with a wind-milling prop as opposed to one with a stopped prop, and thought I'd test it to find what the story was for my KR...because I figured it'd be good to know some day. So one calm morning I climbed to 10,000' and noted altitude, compass heading, direction, speed (best glide being about 80 mph), and then started a timer and pulled it back to idle. I glided all the way down to 2000' maintaining 80 mph all the way down (pretty close, anyway), and stopped the timer. Then I landed, replenished the two gallons of fuel I'd used, climbed back to 10,000', took the same heading, started the timer (same heading and altitude), and switched the ignition off to get a dead prop. Because I have a high compression engine with a short, light, prop, the engine doesn't windmill at any speed that I've tried, but certainly not at 80 mph. Again I glided down to 2000' , stopped the timer, and divided out the numbers. They were almost identical, and certainly within the range of any kind of measurement error. I only mention this for informational purposes, as it may come in handy someday for similar KRs. Another useful tidbit is that the glide ratio for my heavy KR2S is just over 12:1 (12 miles horizontal for every mile of altitude).
I'm guessing that a low-compression O-200 with a larger and heavier blade might continue to windmill with the engine off, but I've never tested that scenario. I'm sure somebody else on the list has, however. Mark Langford, Harvest, AL ML at N56ML.com www.N56ML.com
