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Glenn, Here's some useful information: First, the type certificate aircraft specifications list the allowed props. These tell what props you can use but only list the allowed range of static rpm (full power with zero wind). To look in the appropriate aircraft specification for your model, scroll down to the bottom of the page and click on the correct link then look for allowed propellers. http://edburkhead.com/Ercoupe/coupe_maintenance.htm Here's a general performance chart from Paul Prentice's book (posted by permission): http://edburkhead.com/Ercoupe/enginepropeller_efficiency.htm For the Ercoupes with the C-85 engine, here are some basic pitch comparisons: 7146 extreme climb prop - static rpm right at limit, climb pretty good even at 1400 lb. gross weight. 100 mph cruise speed at 2400 rpm 7148 climb prop 104 mph cruise speed at 2400 rpm 7150 "normal" prop - climb insipid IMHO - good for a model C or CD flown within 1260 lb. - may be OK for heavier planes flying over the great plains. 108 mph cruise speed at 2400 rpm 7152 "cruise" prop - climb rate is above legal minimum (which isn't saying much). If flown heavy, I've had people tell me their plane climbed like a skunk and cruised like a skunk. They didn't have enough power to turn the prop up to speed to get the possible 112 mph cruise speed. Others have owned this prop without complaint. I think it may be nice on a plane flown very light, such as under SP rules but no promises. I liked having the 7146 because I'm heavy and often flew in the upper ranges of gross weight. In addition, I get airsick easily and like the ability to climb above the bump layers. Also, it did well for me going out west, over the mountains, (flying solo). It may have only cruised at 100 mph, but I flew from coast to coast with this prop. I think I've heard that a prop may only be repitched twice. For what it's worth, that's my information and opinion. Ed Burkhead http://edburkhead.com ed -at- edburkhead???.com (change -at- to @ and remove "???") ============================================================================== To leave this forum go to: http://ercoupers.com/lists.htm
