If pitch = speed, and throttle = altitude...

[KevinAu 441]

And now we move on to the non-idealized discussion where all the vectors are not found in their usually depicted locations.

 

I've been through this debate with LAadsmson many times before. But you make a great observation right off the bat. All his arguments are based on lift and gravity pointed in directions other than opposite of each other and perpendicular to the chord line or with the aircraft being supported by the ground. Wait till he goes inverted.

[n4gix 4,947]

FWIW Kevin, I promoted your excellent precis to the Tutorial section for archival and future reference.

 

I might add too that while both "techniques" are technically correct, the technique you are advocating at least has the major benefit of consistency under all circumstances, with "muscle memory" always commanding the correct response. This in and of itself recommends this technique during abnormal conditions.

 

The other technique requires "mental memory/judgment" that under stress may very well result in a poor/incorrect evaluation and response being made.

[KevinAu 441]

Thank you. This was just how it was explained to me when I learned to fly and how I passed it on to my students when I was a cfi. It is not meant to be rote technique but as an understanding of what each control does so that the pilot can naturally do the right thing.

[OmniAtlas 93]

Thank you all for the educational lesson and your insights. Cheers

[LAdamson 240]

Wait till he goes inverted.

I admit, than in my flying days, I did make it a point to take aerobatic courses. My own plane was semi-aerobatic. Unlike a Pitt's it gained too much speed on the down line. I must have done something right, as I'm still here...

[japascoe 98]

I've been through this debate with LAadsmson many times before. But you make a great observation right off the bat. All his arguments are based on lift and gravity pointed in directions other than opposite of each other and perpendicular to the chord line or with the aircraft being supported by the ground. Wait till he goes inverted.

 

Conversely your arguments seem to be based on assuming the aircraft jumps between equilibrium situations. It probably is the best way to understand the proper flying technique, but it does skip over some of the physics of the problem.

 

Starting from straight and level in equilibrium, increasing thrust will produce a forward acceleration (as thrust no longer equals drag), this will increase airspeed, increasing lift. Lift is now no longer equal to weight, producing an upward acceleration (i.e. you start to climb). Simultaneously the increase in airspeed will increase the drag, while the change in your flight path vector will likely change your angle of attack, again changing lift and drag, etc. Eventually that will all stabilise out and leave you in a new equilibrium situation. I'm not a good enough flight dynamiscist to reason out what that new equilibrium would be, so I'll defer to your experience that it is indeed a steady climb.

 

Note that I'm an engineer, not a pilot, so I'm approaching the problem from a different angle (understanding all the physical details, versus understanding what the practical effect of manipulating the controls is). In my experience many arguments about 'what really happens' are cause by people not being clear on what assumptions they are using and/or using different levels of detail. See also the debate on what really causes lift .

[KevinAu 441]

Conversely your arguments seem to be based on assuming the aircraft jumps between equilibrium situations. It probably is the best way to understand the proper flying technique, but it does skip over some of the physics of the problem.

 

Starting from straight and level in equilibrium, increasing thrust will produce a forward acceleration (as thrust no longer equals drag), this will increase airspeed, increasing lift. Lift is now no longer equal to weight, producing an upward acceleration (i.e. you start to climb). Simultaneously the increase in airspeed will increase the drag, while the change in your flight path vector will likely change your angle of attack, again changing lift and drag, etc. Eventually that will all stabilise out and leave you in a new equilibrium situation. I'm not a good enough flight dynamiscist to reason out what that new equilibrium would be, so I'll defer to your experience that it is indeed a steady climb.

 

Note that I'm an engineer, not a pilot, so I'm approaching the problem from a different angle (understanding all the physical details, versus understanding what the practical effect of manipulating the controls is). In my experience many arguments about 'what really happens' are cause by people not being clear on what assumptions they are using and/or using different levels of detail. See also the debate on what really causes lift .

Of course you are right that I am focusing on the steady parts of flight for the purposes of better understanding. Of course I have to leave parts out, I mean I didn't even describe a deceleration or a descent in the above posts, let alone the brief transition between phases. Don't you think my posts are long enough? I will say that as far as human perception goes, the transition from adding power to the climb or need to push forward on the stick to hold altitude and accelerate is instantaneous. On the PFD of my aircraft, there are trend indicators that show where your altitude and airspeed will be in 6 and 10 seconds, respectively. When I pull back on the stick, the 'worms' as we call them, extend out simultaneously in opposite directions. There is no delay where the airplane takes a few seconds to think to itself that since speed is decreasing, I'm feeling less drag, ooh I should start a climb now. It just shows a deceleration and a climb simultaneously. The equation for lift only has parameters for Cl, air density, speed and wing area. There is no parameter for some sort of reaction delay for continued momentum, which is one of the things that LAdamson has been focused on. This reaction delay that he uses as part of the reason for pitch for altitude really seems like a projection of a human trait onto physics.

[Christopher Low 5,331]

Airliners with their slats and flaps extended and not 30 knots below their ref speed...are examples of aircraft that make their landing approaches this way

 

I bet they felt that one all the way from San Francisco.

[Brett_Henderson 5]

Terminology is important in this discussion.. most importantly, the difference between, "cause" and "control", and the difference between, "altitude" and "vertical speed"

 

Pitch causes AoA  hence controls airspeed...

 

Power causes thrust hence controls vertical speed (not altitude)..

 

Of course , all of this assumes an aircraft in flight.. not an aircraft on the runway, before any AoA change can happen (or like our poor, comic pilot trying to cause a change of AoA, planted on a runway).. lol

 

A similar set of physical facts apply to our other, oft-debated topic.,, constant-speed props. A prop blade's version of airspeed (RPMs), is controlled the blade's AoA (pitch)...the prop blade, "pitches" for the selected "speed" (RPM).. And a prop blade's version of vertical speed, is thrust.. which is controlled by power... changes in power do not change RPMs, they "control" thrust.

[fppilot 4,339]

Still amuses me to this day that back when I taught ground weather school to Army pilots it was the rotary wing pilots that grasped these concepts and their relationships first.