apexlined Posted November 25, 2010 Share Posted November 25, 2010 What the meaning power off stall and power on stall? Quote Link to comment Share on other sites More sharing options...
tenten Posted November 25, 2010 Share Posted November 25, 2010 "Power off" stalling speed by definition is: The minimum speed at which the aircraft is controllable with deceleration not greater than one knot per second and with flight idle thrust at the stalling speed. This type of stall normally encounters during descending or approach to landing. While "Power on" stalling speed; Is the minimum speed at which the aircraft is controllable… while thrust power at maximum at the stalling speed. This type of stall normally encounters during take-off, climb, or go-around when higher than normal pitch-up is used. The “recovery procedures” to regain aircraft control slightly differ for each of the two types of stall. Quote Link to comment Share on other sites More sharing options...
BobWoods Posted November 25, 2010 Share Posted November 25, 2010 Just what it says, the IAS that the plane will stall with throttles at flight idle vs the throttles at take off setting Quote Link to comment Share on other sites More sharing options...
RavenFE Posted November 30, 2010 Share Posted November 30, 2010 A power-on or power-off stall will occur when the critical angle of attack of the wing is exceeded and the wing is no longer producing lift. Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted November 30, 2010 Share Posted November 30, 2010 A power-on or power-off stall will occur when the critical angle of attack of the wing is exceeded and the wing is no longer producing lift. With power on (max power on engines) the prop will blow (more) air over the wing vice power off "less" air being "blown" over the wing. 120,000 aircraft wings level, power off stall speed is 95kias, power on stall is 78kias (max effort take off is 1.2 power on stall or 93kias) Quote Link to comment Share on other sites More sharing options...
AMPTestFE Posted December 1, 2010 Share Posted December 1, 2010 With power on (max power on engines) the prop will blow (more) air over the wing vice power off "less" air being "blown" over the wing. 120,000 aircraft wings level, power off stall speed is 95kias, power on stall is 78kias (max effort take off is 1.2 power on stall or 93kias) Of course, those numbers are probably for what...50% flaps? I'm here to tell you that you can fly an H3 100% flaps below what the IAS indicators will read (<60kts). Quote Link to comment Share on other sites More sharing options...
Railrunner130 Posted December 1, 2010 Share Posted December 1, 2010 I'm amazed by how low a speed the wings will lift. Thankfully, I've never had to experience liftoff below the "rotate" speeds. It's like a giant Cessna. My $$ says that if it were to come down to it, a Herk will come really close to the Cessna speeds. Quote Link to comment Share on other sites More sharing options...
AMPTestFE Posted December 1, 2010 Share Posted December 1, 2010 Close, but not quite....but we didn't try it at really low gross weights either! We were testing what the 8-bladed props would do to the stall characteristics at different configurations. We were 100% flaps, gear up (CB pulled to get rid of horn), and power at 10,000inlbs. She broke loose into a stall somewhere between 50 & 60 kts. Don't care to repeat that...ever! Quote Link to comment Share on other sites More sharing options...
Jake Posted December 1, 2010 Share Posted December 1, 2010 I think the 2 closest full power on stalls I know about are the dyess bird that went down at Pope in '88 (I think) when the parachute for the heavy came out the crew was at full power and essentially they flew it to the groound (where they pancaked). For the stall they were not able to produce enough thrust to get speed but they had enough to not plummet to earth. The other was the power on stall in afghanistan with the MC that went into the hill. Even in in that extreme pullup they lost speed but had enough lift to break their fall - so-to-speak. While a power on stall is a horrible thing to speak of - the Herk is the plane to be in. BTW all the charts for power on stall are estimated..... Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted December 2, 2010 Share Posted December 2, 2010 Of course, those numbers are probably for what...50% flaps? I'm here to tell you that you can fly an H3 100% flaps below what the IAS indicators will read (<60kts). YES 50%... It was to make a point and the only reference to Power ON stall is in the Takeoff and Obstacle clearance speed calculations... 100% flaps more "wing", same wind, more lift ='s slower speed.... Quote Link to comment Share on other sites More sharing options...
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