skylor
Well Known Member
****THIS THREAD IS NOT ABOUT ENGINE OUT TURN-BACKS ON TAKEOFF. PLEASE DON'T BRING IT UP!****
This evening I went up to find the High Key and Low Key numbers for my RV-8.
Previous discussions about this subject here:
Rocket Glider
And here:
High Key approach in a -10
Admittedly this is something I should have done many years ago. Somehow I never seemed to remember to do it or find the time for this. Recent reflections of a fatal accident of an acquaintance (not in an RV) that occured about a year and a half ago finally convinced me to go do this.
For the test, I climbed to 4500’ msl (4400 all) above my home field, entered the “upwind,” pulled the mixture to idle cutoff and established stabilized best glide (95 - 100 kias) straight ahead until 4000’ and then entered a 45 degree banked turn. I maintained the turn at the same speed through 360 degrees, noting altitude at the 180 and 360 degree points. At these conditions, the altitude loss at 360 degrees ( high key) was ~ 1150’ and ~ 550’ at 180 degrees (low key). I repeated this 4 times and the results were very consistent. I ran an additional attempt (actually, my first one) at 30 degrees bank and the numbers were ~ 1450’ and 750’ for high key/Low key respectively.
My RV-8 is equipped with a stock IO30-A1B6 (angle valve) and 74” Hartzell blended airfoil constant speed propellor. I ran all tests with the mixture at idle cutoff, the throttle fully retarded, and the prop control full forward.
I recommend testing this yourself in your own aircraft.
Skylor
****THIS THREAD IS NOT ABOUT ENGINE OUT TURN-BACKS ON TAKEOFF. PLEASE DON'T BRING IT UP!****
This evening I went up to find the High Key and Low Key numbers for my RV-8.
Previous discussions about this subject here:
Rocket Glider
And here:
High Key approach in a -10
Admittedly this is something I should have done many years ago. Somehow I never seemed to remember to do it or find the time for this. Recent reflections of a fatal accident of an acquaintance (not in an RV) that occured about a year and a half ago finally convinced me to go do this.
For the test, I climbed to 4500’ msl (4400 all) above my home field, entered the “upwind,” pulled the mixture to idle cutoff and established stabilized best glide (95 - 100 kias) straight ahead until 4000’ and then entered a 45 degree banked turn. I maintained the turn at the same speed through 360 degrees, noting altitude at the 180 and 360 degree points. At these conditions, the altitude loss at 360 degrees ( high key) was ~ 1150’ and ~ 550’ at 180 degrees (low key). I repeated this 4 times and the results were very consistent. I ran an additional attempt (actually, my first one) at 30 degrees bank and the numbers were ~ 1450’ and 750’ for high key/Low key respectively.
My RV-8 is equipped with a stock IO30-A1B6 (angle valve) and 74” Hartzell blended airfoil constant speed propellor. I ran all tests with the mixture at idle cutoff, the throttle fully retarded, and the prop control full forward.
I recommend testing this yourself in your own aircraft.
Skylor
****THIS THREAD IS NOT ABOUT ENGINE OUT TURN-BACKS ON TAKEOFF. PLEASE DON'T BRING IT UP!****
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