Throttle and elevator - which does what?
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Oh my Gowd I can hardly believe some of the comments in this thread! Mickey Mouse school of flying comes to mind 
Just imagine a bike sitting on a pivoted straight construction! Wind the construction forward and the bike will roll forward, wind it back and lo and behold the bake will roll backwards keep it horizontal and you are not going anywhere.
What is controlling speed? Now add an engine to the bike and the bike can move under power when the construction is horizontal it can even climb if you wind a slope uphill into the equation! Wind in too much and the poor little engine will not cope.
Wind the slope forward engine, bike and your weight and you will accelerate like mad.
Conventional peddle bike you are the engine. You peddle like mad uphill you sit there doing nothing downhill.
Aircraft! No rule in isolation is correct! Low powered draggy aircraft with novice pilot and pitch becomes more relevant for speed but pitch is purely the throttle which allows you to tap into the potential energy in the airframe!
Its that energy which gives the speed, The Elevator is just the throttle!
High powered aircraft power can become more relevant but you are regardless managing the energy available to you from the engine and airframe to achieve a desired effect.
So think two throttles two energy sources and both are available to you to use!
The glider on a no lift calm day only has one energy source and that is from the airframe by trading altitude for energy which gives enough speed for the wing to fly. The elevator is the throttle to that energy source! push forward and the speed will increase pull back and it will decrease! pull back too far and that energy will climb the aircraft.
In a typical low powered draggy trainer the biggest danger with novice students is keeping them away from stalling the aircraft. In these aircraft pitching for speed becomes more relevant as with little engine power available there is a danger of the student gettting into a high drag high AOA situation with minimal power which is a lethal combination so teaching them to pitch for speed is vital although only part of the true picture and principal.
For more advanced experienced pilots they will use a combination of both energy sources sometimes more from one source sometimes more from the other sometimes some of both, sometimes none from one all from the other and visa versa hence why I prefer the description of energy management.
Its energy which always gives you speed its the throttle AND elevator which controls that speed as well of course as drag that is available to you
Pace
Just imagine a bike sitting on a pivoted straight construction! Wind the construction forward and the bike will roll forward, wind it back and lo and behold the bake will roll backwards keep it horizontal and you are not going anywhere.
What is controlling speed? Now add an engine to the bike and the bike can move under power when the construction is horizontal it can even climb if you wind a slope uphill into the equation! Wind in too much and the poor little engine will not cope.
Wind the slope forward engine, bike and your weight and you will accelerate like mad.
Conventional peddle bike you are the engine. You peddle like mad uphill you sit there doing nothing downhill.
Aircraft! No rule in isolation is correct! Low powered draggy aircraft with novice pilot and pitch becomes more relevant for speed but pitch is purely the throttle which allows you to tap into the potential energy in the airframe!
Its that energy which gives the speed, The Elevator is just the throttle!
High powered aircraft power can become more relevant but you are regardless managing the energy available to you from the engine and airframe to achieve a desired effect.
So think two throttles two energy sources and both are available to you to use!
The glider on a no lift calm day only has one energy source and that is from the airframe by trading altitude for energy which gives enough speed for the wing to fly. The elevator is the throttle to that energy source! push forward and the speed will increase pull back and it will decrease! pull back too far and that energy will climb the aircraft.
In a typical low powered draggy trainer the biggest danger with novice students is keeping them away from stalling the aircraft. In these aircraft pitching for speed becomes more relevant as with little engine power available there is a danger of the student gettting into a high drag high AOA situation with minimal power which is a lethal combination so teaching them to pitch for speed is vital although only part of the true picture and principal.
For more advanced experienced pilots they will use a combination of both energy sources sometimes more from one source sometimes more from the other sometimes some of both, sometimes none from one all from the other and visa versa hence why I prefer the description of energy management.
Its energy which always gives you speed its the throttle AND elevator which controls that speed as well of course as drag that is available to you
Pace
Last edited by Pace; 4th Jul 2013 at 09:03.
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Power + Attitude = Performance
With the combination of a power setting and an attitude the A/C will achieve a specific performance, simple as that.
Keep in mind performance is judged by lateral, vertical and linear (airspeed) quantities and not just one individual parameter.
So changing just one variable in the above equation will affect the performance in more than just one parameter, if you want to adjust speed but want to keep ROD/ROC constant both attitude and power must be adjusted to get that performance not just one alone.
What dose this all mean? well both throttle and yoke can change air speed and vertical speed, keeping in mind that when used independently or uncoordinated there will be a secondary, possibly unwanted or opposite effect as described in many of the previous posts.
Whatever action comes first it is the combination that gives us our performance be it what we want or not.
With the combination of a power setting and an attitude the A/C will achieve a specific performance, simple as that.
Keep in mind performance is judged by lateral, vertical and linear (airspeed) quantities and not just one individual parameter.
So changing just one variable in the above equation will affect the performance in more than just one parameter, if you want to adjust speed but want to keep ROD/ROC constant both attitude and power must be adjusted to get that performance not just one alone.
What dose this all mean? well both throttle and yoke can change air speed and vertical speed, keeping in mind that when used independently or uncoordinated there will be a secondary, possibly unwanted or opposite effect as described in many of the previous posts.
Whatever action comes first it is the combination that gives us our performance be it what we want or not.
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Then ATC controls the speed innit.
Many times ATC have given me an instruction I cannot comply with or attempt to comply with but cannot then its a matter of telling them "no can do" !!!
Not much to do with the thread but added it anyway as ATC do not ultimately control the aircraft. You do
Last edited by Pace; 4th Jul 2013 at 13:16.
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It may be useful to consider what the throttle and elevator actually control.
Throttle (to a very close approximation ) controls the rate chemical energy is removed from the fuel tank and added as mechanical energy to the aircraft.
Elevator sets the Cl and Cd, changes in which generally exchange kinetic and potential energy. This also changes the rate of energy dissipation. For many speed ranges this is a rather marginal effect, however well above or below best glide, the effect can be very pronounced (I.e energy dissipation at Vy, Vbg, Vx will all be much much lower than Vso-20%)
The kinetic energy can be exchanged most quickly but is generally most limited in supply.
My instrument instructors tended to teach the lazy mans approach of trim for the air speed you want, use power to adjust your overall ROD (energy dissipation rate in this case), use small elevator input to address short term transients in energy dissipation (I.e. a transient move above GS due to a gust or air column off the parking lot)
Throttle (to a very close approximation ) controls the rate chemical energy is removed from the fuel tank and added as mechanical energy to the aircraft.
Elevator sets the Cl and Cd, changes in which generally exchange kinetic and potential energy. This also changes the rate of energy dissipation. For many speed ranges this is a rather marginal effect, however well above or below best glide, the effect can be very pronounced (I.e energy dissipation at Vy, Vbg, Vx will all be much much lower than Vso-20%)
The kinetic energy can be exchanged most quickly but is generally most limited in supply.
My instrument instructors tended to teach the lazy mans approach of trim for the air speed you want, use power to adjust your overall ROD (energy dissipation rate in this case), use small elevator input to address short term transients in energy dissipation (I.e. a transient move above GS due to a gust or air column off the parking lot)
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Oh my Gowd I can hardly believe some of the comments in this thread! Mickey Mouse school of flying comes to mind
It is brilliant, I have learned that if I push on the stick the cows get bigger quicker than they get smaller if I pull. Eventually!!
