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Hi all, I just had a question for the group to see if this was a common 'feature' of the Mooney POH. I'm a new owner of a 1969 M20G and was reading the POH to find out what my Vx, Vy would be at KSLC (4200'). I looked in the performance section and found a table (in my POH, on pp 6-5) that listed various Rates of climb in Feet per Minute(FPM) and Miles Per Hour (MPH) against Altitude. It also had one column of Best Angle of Climb in MPH against Altitude. It took me a while to notice but the best angle of climb speed was the same, at 82 MPH, for every altitude from Sea Level (SL) to 13000 feet. In my head I thought that made sense as pressure decreases with Altitude and the speed(over the ground) for angle of climb would increase as my altitude increased etc. Not well thought out I know, but being lazy I didn't think about it further. Today I noticed that another section (under 'CLIMB' on pp 3-14, NORMAL PROCEDURES section) of the POH has this quote in it "The speed for maximum angle of climb (for obstacle clearance at full power, gear down, and flaps set at TAKEOFF) is a straight line variation from 81 MPH IAS at sea level to 72 MPH IAS at 10,000 feet." Well, I thought to myself, that doesn't jive with what is in the performance table! What the <insert expletive of your choice here>. Went to google and started a little research on Vx and how to calculate etc. Found a good article (IMHO) here. (http://cospilot.com/documents/Why Vx and Vy Change with Altitude.pdf). SO my question - The only difference between the two recommendations for Vx is that in the performance table, the conditions are enumerated to be GEAR UP, FLAPS UP and the speed for Vx is a constant 82 MPH without variation for altitude, while in the NORMAL PROCEDURES the conditions are defined as GEAR DOWN, FLAPS SET FOR TAKEOFF, and then Vx is a variable speed between 81 and 72 MPH. - What speed do I use? Is the performance table set to 82 for best cooling or something? Do different configurations affect the variable speed of Vx? Why is Vx variable in one configuration and not in another when it would seem to me that Vx should just vary with altitude. What am I missing here? Cheers Cam