Adding power in a Cessna lowers the stall speed by blowing air across the wings and reattaching the flow
Yes, though for a rather small amount of the span.
The benefits in stall recovery are not just about increasing the airspeed.
Absolutely. Reduction in the angle of attack will unload the wing. A reduced requirement to create lift, and reduction in drag, both of which aid in stall prevention or recovery, even if the speed has not changed at all. The effect will, however, be momentary, and speed will have to be increased before long.
That's called "induced lift". ie the propwash blows directly onto the upper surface of the wing directly creating an increased lift vector.
Secondly, AOA is measused between the relative airflow and the chord line of the airfoil. Thrust directly on the wing effectively reduces said AOA albeit on a small portion of the inner wing but never the less, just adding power alone on a wing that hasn't fully stalled may "power through" the stall. Especially since washout in a 172 means the inner wing has a slightly higher AOA to keep some aileron authority approaching the stall.
Sure wouldn't want to try it out close to the ground though. Best to stick with plan A. Check forward, max power, reduce drag...
In the approach (after descending in the Cardinal in a cruise descent at 110-120 from the high altitude across 28 miles of pitch black terrain from the north) the airport lights are very bright about a mile out (the no-flap "mistake" there) while approaching in "flat" pitch to lose the last ten knots in slowing to 75knots for the final. The slowing was in progress even before the shear zone affected the flightpath. Figured out later that from 85 to 75 it only lost about 5kt groundspeed and only 5kt more lost on the way to the "62knots" airspeed, and the AS decayed from 75 IAS to 62kts very quickly, about 23kts IAS lost during those few seconds while slowing those 10kts GS in smooth air ... thus not able to feel the decay going so-far-down/so-quick.
Yes, 'gave it max power in checking forward' there ... but figured out later it must have been down to around 59GS when at 62IAS as the extra power kicked in, then maintaining the 62kt AS during the next seconds in descent most of the way to the runway as GS climbed in knots; feels "long" / like forever as airspeed didn't rise while GS climbed. The "speed" / the GS ... the momentum .. now had to increase in the negative shear just for airspeed to hold steady, so in holding the 62kts-AS it became a 65-66kt GS (7 knots of increase from 59 to 66kts at the constant IAS of 62) as the 24 touchdownzone got closer.
The increasing "drag" was in 'check' right away, which noticeably contributed to the just-barely stabilized AS; but the increase in GS , which is the momentum increase where GS surpasses IAS, was now in progress. I suspect this is where MOST of the excess power available at the max power setting went (yes, where did all that power go ?) .. here where a near max-gross / descending aircraft's IAS can barely maintain let alone rise as the GS climbs above its IAS.
In minimizing the sinkrate in those few moments after "check forward" / "max-power" (ie lessening drag / to gain speed / to prevent stall while minimizing the nosedown action) it also becomes very obvious the alternative, the steeper pitchdown, requires too-much G-force immediately after ... ie with a premature pull-up into stall or else continuing that steeper descent angle toward the ground.
As it was, no flaring to speak of despite pulling the yoke back to nose high and tail nearly touching as mains contacted extemely hard (a very loud bang) while still at full power, a considerable height achieved in the bounce of 100ft plus while reacting to stabilize the/then unexpected pitchup from the pavement so that the go-around (767 tm) was automatic.
Few seconds and a few hundred feet further along/above the runway there immediately was the positive headwind again, a strong 'relative' increase expediating IAS-increase thru 75kts despite a steep "bounce" climb-rate, which could have easily reduced AS but was now at the positive/top side of this shear zone's transition. A very noticeable airspeed-gain as the 2 speeds (at about 200ft above the first quarter mark of the runway) reverted back ... to the groundspeed being lower than the airspeed just like before entry and to about the middle of this particular shear transition. Being very closely aligned in heading & slope to the flightpath it produced the maximum possible negative shear effect on the near max gross 177 at the same time and place in my shallow approach where I knew that 20 degrees of flap was the required procedure.
Lesson Learned: Once the decay was noticed, if I'd used the normal / steeper approach with flap deployed, it leaves 1400-1500rpm of power to add (the 177's idle descent is ~ 1000rpm) which enables the maximum possible lift production as soon as that power is added when the need arises ... as it did there ... without any warning.
Dropping the nose and at some point adding power is taught in schools,,,like landing straight ahead in an engine out situation. Once kindergarden is over and boys become men its time to talk ACTUAL recovery procedures for the specific occasion in a specific A/C. In a partial stall ( incipient) at LOW altitude, full power WILL increase the lift and reduce the stall speed, so a SLIGHT lowering of the nose, level the wings (1/4- 2 degrees?) combined with full power, ( watch the ball ) will be a better recovery procedure than what is taught at altitude to a 50 hr wonder
Just a thought, I'm no expert and I'm still learning but if you are stalling and you have a high AOA. If you add full power without lowering the nose first is there a possibility of you entering a spin especially if you aren't on top of the rudder? Correct me if I'm wrong? Would that be a reason we are taught to lower the nose first then add power.
danishroy wrote:If you add full power without lowering the nose first is there a possibility of you entering a spin especially if you aren't on top of the rudder? Correct me if I'm wrong?
Yes
danishroy wrote:
Would that be a reason we are taught to lower the nose first then add power.
Yes
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The power off stall practiced at altitude NEVER happens in a real life scenario! most accidents resulting from a stall have some power on and the ball not centred. Once the stall recovery is mastered, ALL instructors should provide real-life scenarios for the student and LEARN to recover with minimum altitude loss. If you practice getting on the rudder ( make those feet work) then, why worry about a spin EVER, it WONT happen. That's another thing ,,, In training you must force the plane into a spin ,,,, a real life spin is absolutely not going to happen the way you are being taught to enter one in training.
The 'rule" about no greater than 15 degrees bank in the circuit, to prevent a spin, for example. Not quite so simple, and the simplication is an issue.
30 degree banks in the circuit are no big deal, IMO, just downwind to base, base to final turn, keep that ball coordinated...and allow the nose to drop. It's not a steep turn excercise. Descending is ok. A steep even slightly descending turn, coordinated and well above the stall, (well above final approach speed too, in actuality) it's hard to see how that could ever turn into spin, because I'm not allowing the AOA anywhere near an issue.
Spins happen from getting too slow in the pattern, maybe too low, making the turn, plus forcing the nose to stay up. There goes the AOA. Could be a 5 degree turn if too close in the first place, or not being coordinated.
Rudder work is really undertaught, maybe its not much needed in a 172. In a 182, there is a considerable difference in rudder pressure needed for an intial left climbing turnout, vs a right climbing, at least to do it right.
Worst I ever did was VFR into IMC on my PPL solo XC. I was a nervous, shy kid, and the thought of trying to figure out who to talk to if I couldn't make it home terrified me. Combine that with a bit of youthful arrogance and invulnerability and you've got a bad situation for get-home-itis. I was on the final leg of the flight out of Gatineau and the clouds were coming down. I kept moving lower and lower until I was around 12 or 1500 AGL but the clouds were lower than that. I dodged a few, poked through a few others and suddenly noticed that the ground was gone. Fortunately I'd already done a fair amount of my instrument training. Unfortunately I was too young and stupid to appreciate the effects of being in cloud. I always told myself that I would be able to feel the plane drifting, that this whole "your inner ear adapts to being in a bank and you don't realize it" was a load of BS, and that I was better than that.
In any case, after a few minutes of watching the instruments I poked my head back out the window to look for ground. Shortly after that I came back inside and hey, would you look at that; I've got a descending right turn going. So, I straighten things out and once I think I've got things under control I take a look outside again and when I look back at the instruments after a matter of seconds I'm straight back in to that nice gentle descending turn.
Anyway, I got on the radio with Montreal Terminal because at this point I'm quite lost and ask for vectors back home. They help me out for a few minutes until I break out of the weather, with the closing remark that there is lightning activity 3 miles south and 2 miles north of me (I'm eastbound). Get back to the airport and it's dark as night with the storm closing in fast. Bombed through the circuit full throttle (in a 152), probably the most challenging landing I've ever made to this day, and at the instructions of the CFI taxied straight into the hangar because they were worried I'd get blown over if I shut down outside.
Scary story!
Similar thing happened to me, north of Baie-Comeau, shortly after my PPL. I wasn't fat on fuel, and the only other landing option was Manic-5, where I had never been, and wasn't expecting any service whatsoever according to the CFS.
"Luckily", I didn't even have a working attitude or heading indicator in the aircraft (and no GPS), and that made my decision to turn around much easier. I ended up landing at Manic-5, and we found fuel, dinner, and a bed there, so it all turned out well. I'm still wondering whether or not I would have pushed through towards Baie-Comeau had I had some instruments in the cockpit...
Just a quick question for all the guys. I have soloed and I had to put a hold on training for about a month about to start up again. When you are flying in the circuit and turning I always have to look down at the ball to keep it centered. I don't mean stare it but ill look down and see I'm skidding so I put in rudder and check make sure it's good. Now do you start to get the feel of the airplane skidding or slipping or do most of you still need to look down at th ball? Is it like a feel you build up as you fly more or do you anticipate what input will be needed and adjust as necessary?
Just a quick question for all the guys. I have soloed and I had to put a hold on training for about a month about to start up again. When you are flying in the circuit and turning I always have to look down at the ball to keep it centered. I don't mean stare at it but ill look down and see I'm skidding so I put in rudder and check make sure it's good. Now do you start to get the feel of the airplane skidding or slipping or do most of you still need to look down at th ball? Is it like a feel you build up as you fly more or do you anticipate what input will be needed and adjust as necessary?
danishroy wrote:Just a quick question for all the guys. I have soloed and I had to put a hold on training for about a month about to start up again. When you are flying in the circuit and turning I always have to look down at the ball to keep it centered. I don't mean stare at it but ill look down and see I'm skidding so I put in rudder and check make sure it's good. Now do you start to get the feel of the airplane skidding or slipping or do most of you still need to look down at th ball? Is it like a feel you build up as you fly more or do you anticipate what input will be needed and adjust as necessary?
Yes, like most things, experience allows you to better anticipate what you need.
Skids/Slips in particular are something you can feel. Try to figure out if you are co-ordinated (or slipping or skidding) and THEN look at the ball to confirm if you are correct rather than letting the ball tell you what is going on. Also make sure that the ball is in fact level when you are on level ground. It is not unusual for them to be off by a few degrees.
Rookie50 wrote:A lot of FTUisms don't happen in real life.
The 'rule" about no greater than 15 degrees bank in the circuit, to prevent a spin, for example. Not quite so simple, and the simplication is an issue.
Please, please, please, everybody stop making statements that indicate something is common to all flight schools when it may simply be an isolated incident. Or a comment that was said to one student at one time in a certain stage of their training. I do not believe it's common at all and have no experience with any flight school that has a blanket limit of 15 degree banks in the circuit. It's an insidious kind of disrespect that creeps into so many threads it seems. It's not warranted and certainly doesn't benefit anyone. If there's an issue, that would be it.
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Rookie50 wrote:A lot of FTUisms don't happen in real life.
The 'rule" about no greater than 15 degrees bank in the circuit, to prevent a spin, for example. Not quite so simple, and the simplication is an issue.
Please, please, please, everybody stop making statements that indicate something is common to all flight schools when it may simply be an isolated incident. Or a comment that was said to one student at one time in a certain stage of their training. I do not believe it's common at all and have no experience with any flight school that has a blanket limit of 15 degree banks in the circuit. It's an insidious kind of disrespect that creeps into so many threads it seems. It's not warranted and certainly doesn't benefit anyone. If there's an issue, that would be it.
Please read my comment in context, which was IMO both proper focus rudder usage and the constant reinforcement of angle of attack as primary are undertaught. I could be wrong but I'd be surprised if AOA is given more attention. I thought of that because I believe that misunderstanding has led to base to final stall spin accidents over the years.
You know, not all comments discussing and analysing training regimes at FTU's, should be taken as FTU bashing. It's not intended that way.
