Pitch & power debate

[Bernoulli]

Ok... Iknow I might be opening a can of worms with this pitch and power question because I know people have been taught all different ways... but , here goes:
Do you pitch for airspeed and power for altitude or vice versa.
I was finally taught by a guy who has been instructing for over 40 years and he saysthe following:
You always will use power for airspeed (such as shooting an approach) except for three situations. You will pitch for airspeed when you have no power left... so that means when you are either climbing with full power or when you have no power... such as an engine out situation. The only other time you will use pitch for airspeed and power for altitude is in very slow flight... like when you are dirty & close to stall speed. He says, other than slow flight, if you have extra power you always use that power for airspeed and use pitch for altitude. What do you think? Thanks in advance for all replies.

 

[LimoDriver]

I think your instructor is correct. I've always thought the "power for altitude and pitch for speed" argument was a little absurd - like instructors were just trying to say that what appears to be obvious is not always obvious.

You always have to use a combination of pitch and power to put the airplane where you want it at the airspeed you want. what's the big deal???

 

[siucavflight]

I teach my students the pitch for speed and power for altitude. I do not however believe it. But that is what the examiners want them to know.

 

[mar]

In ten words or less: It depends

I don't have the energy to rehash all of the aerodynamic principles but think of it this way.

Back side of the power curve (slow): Power for alt; pitch for airspeed.

Front side of the power curve (fast): Power for speed; pitch for altitude.

You know it's true. You do it all the time. Think about it. Draw out a power/lift/drag curve.

Fly safe.

 

[Timebuilder]

Let's say we are in an airplane.

All I can control is the yoke (pitch) and all you can control is the throttle (power).

No matter what, I can always control the speed of the aircraft. You add power, I add pitch, we are still going slow. You take power away, I pitch down, I can make us go as fast as I want.

I however cannot make us climb one foot until you add power, and we will have a very hard time making a decent with power applied, as Vne will happen very quickly if you add power to keep me from decending.

That's why it is taught that way.

 

[lookup]

Timebuilder...

I thought the pleebs (including all of us at one time) were taught that so we didn't kill ourselves when we got WAY behind the power curve (ie. any flight profile in a Tomahawk)...

 

[oldp3guy]

Timebuilder: "Let's say we are in an airplane. All I can control is the yoke (pitch) and all you can control is the throttle (power).
No matter what, I can always conrol the speed of the aircraft."

This one's been around for longer than I can remember.

Tell you what; you hold that yoke forward and when we get to V1, call it out and then I'll add power and we'll climb out of here!

 

[Deftone45075]

That was funny oldP3guy!

How about considering pitch + power = performance. You need both to climb, and both to descend.

Without changing pitch (to relative wind) if you reduce power you WON'T slow down. You'll lose altitude.

You change one and you change the other. They both work together until you reach certain extremes as stated in the first post.

 

[bobbysamd]

Seconded

You always will use power for airspeed . . . .

. . . and pitch for altitude.

Your instructor is absolutely correct. Think about it this way.

How do you make the airplane climb? You point the nose up. How do you point the nose up? With pitch.

How do you make the airplane go faster or slower? You add or reduce power.

Those who believe that power controls airspeed should consider a Learjet. If you add power to a Learjet without adding back pitch it will go down.

This principle will work in any airplane you fly and not soley in spamcans. Not only is it correct, it is the FAA party line.

The exceptions that your instructor cited are also correct. In slowflight, you are in the region of reversed command - or, as Mar put it, backside of the power curve. Look for the chart in your Flight Training Handbook or Pilot's Handbook of Aeronautical Knowledge.

 

[Loafman]

Let's say we are in an airplane.

All I can control is the yoke (pitch) and all you can control is the throttle (power).

No matter what, I can always control the speed of the aircraft. You add power, I add pitch, we are still going slow. You take power away, I pitch down, I can make us go as fast as I want.

I however cannot make us climb one foot until you add power, and we will have a very hard time making a decent with power applied, as Vne will happen very quickly if you add power to keep me from decending.

That's why it is taught that way.

Ok, We're in an airplane. Sitting in postion on the runway. You pitch for Vr and see if we accelerate.

 

[jergar999]

I have two things to add here:

On final to a runway with the airplane trimmed for hands off flight at the proper airspeed the desired glidepath (and therefore altitude) can be acheived by the use of throttle alone.

If I trim an aircraft in cruise flight to maintain altitude and then add or reduce power I can't maintain altitude without a pitch change.

Admittedly, the theory of pitch for airspeed and power for altitude doesn't always hold true but understanding the direct and indirect effects of power and pitch in all flight conditions helps to develop good habits with power and speed management in students.

 

[jayme]

Loafman says:

"Ok, We're in an airplane. Sitting in postion on the runway. You pitch for Vr and see if we accelerate."

I say :

"OK, we're in an airplane. 10,000 feet in the air. I pull the power to idle and see if we slow down (without messing with the yoke)."

There's a reason gliders can't take off without a tow. Even if I put it on the back of a truck and speed down the road at 100 mph, that glider isn't going to make it more than a couple hundred feet off the ground.

 

[dash8driver]

i think we all agree that in the end, it takes a combination of power + pitch to get the desired effect. i also believe that its broken up like that to be taught to instrument students. it makes it easier for some students to perform when its separated out, rather than having them pushing and pulling the yoke/throttle trying to get some kind of combination to work. then as they fly, more and get more experience they are able to use a combination of both.

kind of like the basic instrument scan being a place to start to teach you how to start scanning your instruments. then later you use a scan that your experience shows works best for you.

 

[Super 80]

I used to instruct in the F-4. One of the "new fangled" gadgets the pilots from UPT (undergraduate pilot training - USAF) had to get used to compared to the T-38 was the "tone."

The T-38 had a simple AOA device for the final turn out of the overhead, or on a straight-in final: a green (if I remember right) circle in the middle, and two red arrows pointing to it, one above pointing down, and the other below pointing up. If you had the lower arrow pointing up lit, you weren't max performing the jet, if the circle was lit, you were right on, but if the upper arrow was lit, you were pulling too hard and were in danger of stalling. The USAF had lost quite a few T-38's and pilots, both students and IP's, from stalled aircraft in the final turn, and this device was put in to assist in understanding how the aircraft was performing. Now for the rest of the story:

Coming into the F-4 from the T-38 was like going from a 70's MGB to a Chrysler Imperial (of the same era) with power steering, power brakes, push button automatic, automatic headlight dimmers and an assorted number of extra gadgets and systems designed to make the only airplane in Air Force inventory that wasn't designed to fly easier for the pilot to operate. One of those gadgets was an aural tone for being "on speed."

"On speed" meant that you were established in the correct AOA for maximum lift of the wing. The early hard wing (blown too with BLC - boundary layer control, hot bleed air off the compressor section [that led to some great airplane fires because there was about 2000 pounds of fuel in each wing] which was deactivated later on) was set at 19.2 units. Don't ask me what a unit was, this is a McDonald Douglas product and their engineering is kind of quirky. Later on, the Air Force put F-106 equalizers on, the slats, and the AOA curve for maneuvering was adjusted upwards and "on speed" became 25 units for air-to-air, but the engineers kept the same attitude for landing so you wouldn't scrape the tail at 19.2 so with the gear down, the tone switched back to the hard wing scale.

If you think this is all confusing, that's how it was to anyone coming out of UPT and Fighter Lead-in too. The tone would come on at 15 with a slow beep. At 17 units it would beep faster and raise a notch in tone. At 19.2 it was steady and a note higher. At 21 it make a ringing tone at a higher pitch and at 22.3 it would reach its highest frequency of rinnging and set off the "foot shaker" - the left rudder pedal would vibrate. (If you think this is a stupid way to build a jet, you're right in some ways, but then again, this was the last jet designed with a slide rule and a drafting board out of the 50's.) (The Russians were a little less forgiving to the pilot, they had a "knuckle rapper" on the stick of their MiG-23.)

Well anyway, this led to a lot of people "landing short" in actual IMC weather conditions. They'd pull the power back on the straight in PAR, ILS or Tacan get the tone and follow the tone right into the ground and make another smoking hole. So I'd take the kid out as part of the syllabus on the Transition rides (where it was just one jet for aircraft handling characteristics) and have the guy configure at altitude and establish a 700 fpm descent on speed. Then I'd tell him to pull the power to idle and maintain on speed. The VVI would be somewhere around 3500 down. Then I would tell him to push the power up to MIL (100% no afterburner) and hold on speed, and the jet would climb at 3500 fpm or something like that all while maintaining the tone.

This would impress them that holding "on speed" was no magical cure-all, especially in the weather for instrument approaches. The simple rule on final was your speed was 155 plus your gas. You established this and would get a tone, and then adjust your glide path control with power. Of course you can "pitch" the airplane in the direction you want to go, but if you don't do the power, you're not going to be "on speed." I would do both to ease the process and still do today when flying an ILS (110.3 and 174 on the inbound to 17C at DFW) in the Super-duper 80.

When I took my son out for his first airplane ride in a C-152, we got established in the working area, I set the RPM at 2300 and told him to hold 90 knots. Then I chopped the power and told him to maintain 90 knots, and we pointed down at a good clip. Then I pushed it all the way in and we held 90 knots and we started to climb. I then repeated this exercise with him holding the aircraft wings level at 60 knots. I then set one power setting and told him to go for different airspeeds. Eventually, each one would establish some sort of equilibrium (although not necessarily level). My son got the picture; you power up and down and hold your airspeed with pitch. He looked over my shoulder just now as I was typing this out. I explained to him what I was doing and he said the amazing part was that he understands it.

Now if you're going along level and you want to speed up and maintain level flight you're going to push it up to go faster. But in order to maintain level flight, you have to "plane" out the aircraft to maintain level flight. Once you reach a new equilibrium between thrust and drag, everything will be in balance again, but your trim will be farther forward. The old 727 would actually get to zero pitch (nose in the hole) around .84 mach.

Of course, you can always trade airspeed for altitude and visa versa. This is one of the beautiful lessons of aviation that nothing is free, but you can make "economic" choices.

But I think a basic understanding of power for altitude and pitch for airspeed will help the pilot out in a situation where he is below on his glide slope in the weather so his first reaction is to add some power as he pitches up a little, reacquires his desired slope, notches back the power to something a little more than he had before as he pitches over to keep the GS centered.

And if I'm fast on the glide slope (as I usually am) I'll notch the throttles back and have to increase my pitch to maintain the slope and catch the airspeed with power again on the backside, but I'm changing an equilibrium here like with pushing it up with level flight. The two are interrelated.

But if you only understand power for airspeed, you're just driving a bus and not flying an airplane.

That’s my 2 cents with a buck twenty-five thrown in for extra measure.

 

[Ty Webb]

The exception to the rule for me was approach in a Sabreliner. It had very minimal flaps, so your final approach was at a pronounced nose-up attitude. You simply set an attitude for your speed (pitch) and maintained your rate of descent with power.

It made "no flap landings" in other jets very simple- it's what I was basically used to, anyway!

 

[Caveman]

This topic is the abortion issue of aviation. Whatever side of the fence you are on it's unlikely that anyone will change your mind.

As for me it's real simple. Point it where you want to go and use power to decide how fast you want to get there. I was originally taught to fly using the pitch for airspeed method and I got by but I wasn't very precise. Later a CFI with about 15K+ dual given taught me how to really fly an airplane using the pitch for attitude/power for airspeed method and it made a world of difference.

The power for airspeed method works best when power is variable and available.

The pitch for airspeed works best when power is not variable or available.

In other words if I'm a glider by design or by circumstance, I'll pitch for airspeed. I have to, there is no other choice. Otherwise I'll use power for airspeed and point the airplane where I want to go.

 

[bobbysamd]

Pitch v. Power for altitude v. AOA

Extremely interesting and entertaining post from Super 80!

I do know that many jets have an AOA indicator and you essentially fly AOA in the pattern. It's almost six of one and half a dozen of another.

 

[rettofly]

i think we all agree that in the end, it takes a combination of power + pitch to get the desired effect.

The combination of pitch and power is always applicable. I used to draw the analogy to driving a car up or down a hill. If you're going up (pitch) you need to step harder on the gas (power), and vice versa to maintain a given speed. Worked great for pre-solo and instrument students.

 

[Mickey]

You're at flight idle descending at 210KIAS and ATC says slow to 190. What do you do? I usually PITCH the nose up a little bit.

If you lose your engine(s) and have no power you will eventually lose altitude but, you can choose what airspeed you are flying at by adjusting your pitch.

 

[Mickey]

I'm descending at 210KIAS and power at idle. ATC asks me to slow to 190. I PITCH the nose up and get the desired speed.
I'm climbing out at 280KIAS and climb power and ATC asks for 300 or better, I PITCH the nose down a bit and the airspeed goes up.

I'm in level flight and ATC gives me a climb, I add power.
ATC gives me a descent, I reduce power.

I remember watching this guy in training 10KIAS fast on an ILS.
It goes something like this....He goes "I'm fast," and pulls the thrust levers back (by the way, he was one dot low). He then says "I'm low," and pulls the nose up. The trend indicator on the airspeed tape draws a pink line down and the instructor starts giving him vocal encouragement which proceeded to get louder and louder until the instructor took control of the aircraft.
This is a real story and a good example of how we have to tie it all together. In this situation all he had to do was pitch the nose up a bit to give up 10 kts and he would have gotten back on the glideslope.

Take care and please...have some fun out there.