Posted for bbriton@telusplanet.net:

Marshal, Jim

I agree about not necessarily taking the IVPT to the full stall in testing or at any time.  I am converting my piston to turbine right now.  Even the piston I never took to stall on my own.

I did however have the set up the AOA properly from the last owner.  These AOA'a that we use need to be set up inflight.  Some of the set up regimes are very close to stall speed.  Does anyone have data as to what their actual stall speeds are clean, dirty, max gross?  I guess the piston speeds should be very close, but is their any indication that it is higher?

Barney Briton


[If you're using one of JIm Frantz's AOA indicators, and if it was calibrated properly by the previous owner, the data it displays will still be correct for your turbine installation.  Jim's instrument actually measures the angle-of-attack on the wing, and as long as the airfoil hasn't changed the critical angles of attack (flaps up and down) haven't changed either.  If you'd like to test its voracity, do an approach to stall maneuver and insure that you're getting the "Angle angle push" annunciation well in advance of the stall... I suspect the (pro) indicator will show an angle indication of about 12 degrees (120 on the display).  You can also test the L/D max indication by doing some gliding GPS runs with power at idle to verify you're getting max range (L/D max = engine out glide) ... I realize this will be a bit different in an actual power off situation, but I suspect you'll be within a knot or two of actual.  You can also simulate some approaches at altitude to insure that the picture you fly during an actual approach is the same one you'd be comfortable with closer to the ground.  The AOA manual has all the testing instructions...  I hope this helps.

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