Starting a New Arguement

[Blackhawk]

That's because you haven't added any throttle for altitude. We are discussing control use in flight.

 

Crank your airplane and pull away from parking. Turn yoke to taxi to runway. Hit FBO building instead. How about some common sense?

You mean you have not traded chemical energy for potential or kinetic energy. The chemical energy can be traded for either kinetic (speed), or potential (altitude), or both. All the different types of energy can be traded as aerobatic pilots know quite well.

Again, trying to say it's "either/or" has probably led to the demise of more pilots than any other confusion in aviation.

[Hank]

Correct! Sitting still on the ground is a zero-energy position, quite unlike flying around the pattern where you need to dissipate both kinetic and potential energy in a controlled manner over a fixed distance [from where you are to the runway with only reduced kinetic energy, which will be brought to near zero by your preferred turnoff.

[PTK]

Control rate of descent with power and pitch for airspeed.

I pick the airspeed I want for the particular conditions and stick with it. Always being careful not to slip behind the power curve and low.

By definition a lot of power is needed to overcome induced drag as the angle of attack increases. Getting behind the power curve all the available power will probably not be enough to maintain altitude and avoid a stall. The only way out is to decrease AOA and go around. Better not be too low!

[spaz]

I think the argument should be over spelling...since you want to argue

[drapo]

For me it is this:

To control airspeed I use pitch

To control altitude (during an approach) I use throttle

Actually the opposite of you Bob!

Yves

Ditto!

[WardHolbrook]

Since there has been a lively discussion on another thread about bank angle and the base turn, I found myself tempted to stray off the thread but have resisted.  Instead I'll start a new one.  Here are the questions:

 

What do you use to control airspeed?

What do you use to control altitude?

How do you control your flight path in the base turn?

 

I'm in the throttle controls airspeed, pitch controls altitude camp.  If I run out of one, the other has to control both (ie full power climb or idle descent).

 

I am fully aware that a change in one will almost always require a change in the other, depending on what you are trying to do.

 

For the base turn I look for a sight picture.  If I'm high I put the nose down to maintain my desired flight path.  If I'm fast or slow I use the throttle to fix it.  And along that line, if I'm high but on speed, I know that when I lower the nose to get back on the path, I'm going to have to reduce power to avoid getting fast and vice versa.

 

Let the mud slinging begin.

 

Bob

 

If you don't know the correct answer to pitch/power question you need to ask your CFI for a refund.

 

How do you guys fly an ILS?

[Hank]

 

How do you guys fly an ILS?

 

I set power for the speed I want, and trim to descend. If I get too fast, I raise the nose; if I get too high, I reduce power slightly.

 

Same as in the pattern--pitch for speed, power for altitude.

[yvesg]

+1 that.  First thing I did 4 years ago when I was in late process of purchasing N10933 before I even had it to do to start Mooney transition training - I purchased Don Kaye's video on landing. Its wonderful esp for me in repeatedly over many days to develop the correct sight picture.  It really helped ease my transition smoothly.  I never actually met you Don but I feel like at one point you sat to my right during my transition.  Thank you!

Well spent few bucks on his video folks!

Erik, if you want to meet Don, join the Mooney Caravan. He was there the last few years.

Yves

[schule]

Sometimes, maybe, and it depends.

Looking forward to watching The Theory of Everything. A zero-energy position is a relative situation I would hypothesize.

The MAPA course is good for learning pitch vs power power settings. Remember though too much of one without the other can lead to disaster.

[alex]

So many AoA haters, what gives?

[WardHolbrook]

I set power for the speed I want, and trim to descend. If I get too fast, I raise the nose; if I get too high, I reduce power slightly.

 

Same as in the pattern--pitch for speed, power for altitude.

Hank,

It's tough to hand fly an ILS approach any smoother than an autopilot can, unless you're using a flight director. In either case - autopilot or flight director - you track the localizer with the ailerons, fly the glideslope with pitch and speed is controlled with power. Personally, I think that method is the one to use regardless of what you're flying - from a Cessna 172 to a Boeing 747. Granted, doing it the way you were taught works OK in small GA aircraft, but if you ever get a chance to fly anything larger - twin turboprops and above - you'll find that that your method simply does not work very well. 

 

If you refer to page 4-6 in the FAA's Instrument Flying Handbook, you'll find the following:

 

Pitch/Power Relationship

An examination of Figure 4-8 illustrates the relationship between pitch and power while controlling flightpath and airspeed. In order to maintain a constant lift, as airspeed is reduced, pitch must be increased. The pilot controls pitch through the elevators, which control the AOA. When back pressure is applied on the elevator control, the tail lowers and the nose rises, thus increasing the wing’s AOA and lift.

 

Under most conditions the elevator is placing downward pressure on the tail. This pressure requires energy that is taken from aircraft performance (speed). Therefore, when the CG is closer to the aft portion of the aircraft the elevator downward forces are less. This results in less energy used for downward forces, in turn resulting in more energy applied to aircraft performance.

 

Thrust is controlled by using the throttle to establish or maintain desired airspeeds. The most precise method of controlling flightpath is to use pitch control while simultaneously using power (thrust) to control airspeed. In order to maintain a constant lift, a change in pitch requires a change in power, and vice versa.

 

If the pilot wants the aircraft to accelerate while maintaining altitude, thrust must be increased to overcome drag. As the aircraft speeds up, lift is increased. To prevent gaining altitude, the pitch angle must be lowered to reduce the AOA and maintain altitude. To decelerate while maintaining altitude, thrust must be decreased to less than the value of drag. As the aircraft slows down, lift is reduced. To prevent losing altitude, the pitch angle must be increased in order to increase the AOA and maintain altitude.

 

This also answers Bob's original question. The answer to which is, "It all depends."   

 

Ward

[WardHolbrook]

Easily proven: set 23", 2400 rpm. Trim for level flight. (Trim = pitch)

Reduce power 2". Don't touch anything else.

Airplane descends, airspeed stays the same.

Therefore power = altitude

And pitch = airspeed.

All that proves is that aircraft will tend to maintain the last speed they were trimmed for. What if you adjusted pitch to maintain a constant altitude and pulled power? Airplane maintains altitude and airspeed decays. Therefore power = airspeed and pitch = altitude.  

[WardHolbrook]

The autopilots in our planes use pitch to stay on glide-slope, because they do not have access to power.  

 

When hand-flying an approach use power to control rate of decent and trim for desired airspeed adding small pitch adjustments as needed and your workload becomes much easier. 

Even jets with autothrottles fly the GS using pitch and adjust power for speed. Your subscribed technique only works with the smallest of aircraft. Using pitch for glideslope and power for airspeed works for all aircraft from C172s to Boeing 747s. 

[M016576]

Airspeed... Speed.... What a bad word to describe what is really an angle of attack... And altitude is a poor way of describing rate of descent.

Pitch, in and of itself sets the optimal angle of attack. Thrust controls rate of descent.

You can pull back on the stick and *temporarily* decrease rate of descent... Or vice versa, but that's not a steady state condition. Really it all occurs in a three part correction: a deviation is noticed, so power is adjusted to adjust rate of descent. That comes with a mandatory pitch correction to recapture the optimal angle of attack, and as that attitude is set, a third, final airspeed correction to establish the new glideslope (VSI).

That's how I was trained, anyway, as a Carrier pilot, and I find those principles work very well for GA as well.

[M016576]

Even jets with autothrottles fly the GS using pitch and adjust power for speed. Your subscribed technique only works with the smallest of aircraft. Using pitch for glideslope and power for airspeed works for all aircraft from C172s to Boeing 747s.

. Kind of.. Depends on how you look at it... It's chicken and egg- you must change the thrust setting when you change your attitude, and vice versa, or you won't be maintaining a stable AoA. The auto throttles on the F-18 held AOA constant based on a pitch input to "move" the velocity vector. When you "moved" the velocity vector with the stick, the throttles would make multiple corrections (albeit small) to capture onspeed aoa. You do the same thing in a mooney when making glideslope corrections, but at amuch slower rate...

The corrections are interdependent on one another- the error that drove you off glideslope could have been thrust, or lift or both. So the appropriate corrections could be either to bring you back down onto glideslope. The autopilot and auto throttles react to keep you where you need to be... But they aren't proactive: so in that respect you are correct- autopilots are typically programmed to handle just G/S and Azimuth... Where the autothrottles have to do the "heavy lifting" of keeping the jet onspeed (at the optimal angle of attack).

[ArtVandelay]

Easily proven: set 23", 2400 rpm. Trim for level flight. (Trim = pitch)

Reduce power 2". Don't touch anything else.

Airplane descends, airspeed stays the same.

Therefore power = altitude

And pitch = airspeed.

If power controls altitude then I assume you give it throttle to flare during landing?

I look at it another way, response time. Effect of changing throttle is slow, since airspeed doesn't require a quick response I use throttle, altitude control requires quick response, I use pitch.

[Andy95W]

Pull onto the runway.  Push and pull the yoke. Nothing happens. Airspeed does not increase.

Pull onto the runway. Pull the yoke. Nothing happens. No power = no altitude.

Since this has now turned completely ridiculous, of course everyone agrees that power & pitch, altitude & airspeed are all interrelated and manipulation of one affects the others.

For myself, I'll stick with Wolfgang Langewiesche and his book _Stick and Rudder_.

[WardHolbrook]

. Kind of.. Depends on how you look at it... It's chicken and egg- you must change the thrust setting when you change your attitude, and vice versa, or you won't be maintaining a stable AoA. The auto throttles on the F-18 held AOA constant based on a pitch input to "move" the velocity vector. When you "moved" the velocity vector with the stick, the throttles would make multiple corrections (albeit small) to capture onspeed aoa. You do the same thing in a mooney when making glideslope corrections, but at amuch slower rate...

The corrections are interdependent on one another- the error that drove you off glideslope could have been thrust, or lift or both. So the appropriate corrections could be either to bring you back down onto glideslope. The autopilot and auto throttles react to keep you where you need to be... But they aren't proactive: so in that respect you are correct- autopilots are typically programmed to handle just G/S and Azimuth... Where the autothrottles have to do the "heavy lifting" of keeping the jet onspeed (at the optimal angle of attack).

I was just trying to keep it simple. Most light aircraft pilots don't understand AoA and have never flown with one. That's why I referenced the Instrument Flying Handbook - The most precise method of controlling flightpath is to use pitch control while simultaneously using power (thrust) to control airspeed.

[Oscar Avalle]

In the pattern, pitch for speed and power for altitude. 

[Jeff_S]

At the risk of moving this thread in a different direction, I will loudly assert that there is only one "e" in argument!

 

Flame on.

[aviatoreb]

At the risk of moving this thread in a different direction, I will loudly assert that there is only one "e" in argument!

 

Flame on.

 

I let it go - I figured Bob must be from England or someplace else where they don't talk Murican proper.  And I thought maybe we were talking about aeroplanes or something.

[Marauder]

At the risk of moving this thread in a different direction, I will loudly assert that there is only one "e" in argument!

Flame on.

And to move this argument even further off track; "I just fly the airplane".

[Marauder]

I was just trying to keep it simple. Most light aircraft pilots don't understand AoA and have never flown with one. That's why I referenced the Instrument Flying Handbook - The most precise method of controlling flightpath is to use pitch control while simultaneously using power (thrust) to control airspeed.

Hey! I resemble that remark!. Actually, as a light aircraft owner and with an AoA installed, I have begun to see the"light". That said;

My conclusion, "it's the man, not the machine" -- Chuck Yeager. Take a look at this video at roughly 2:15.

http://youtu.be/MSWz55b_jtE

[wishboneash]

 

 

If the pilot wants the aircraft to accelerate while maintaining altitude, thrust must be increased to overcome drag. As the aircraft speeds up, lift is increased. To prevent gaining altitude, the pitch angle must be lowered to reduce the AOA and maintain altitude. To decelerate while maintaining altitude, thrust must be decreased to less than the value of drag. As the aircraft slows down, lift is reduced. To prevent losing altitude, the pitch angle must be increased in order to increase the AOA and maintain altitude.

 

 

I look at this differently and I have had discussions with some CFI/CFIIs on other forums on this topic. If you are maintaining level flight and at say 100 knots and want to increase your airspeed (let's say to 120 knots), the first thing you do is pitch down to increase airspeed (from the original premise that pitch controls airspeed and power controls altitude). As soon you do that, you are moving into a higher energy regime (i.e maintaining same altitude but demanding 20knots more airspeed). If you don't do anything about it (i.e. add power), you are going to go down. It has nothing to do with the fact that you pitched down that you are going down. It has to do with total energy. So you add power to maintain the altitude.  On the ILS you may be going down at 500fpm at say 90 knots, if you want to go slower, you pitch up. Now you have too much energy (same rate of descent desired), so you cut some power until you see the same -500fpm again. I think for long term stable flight this is the right way to fly and there is no confusion on what controls what. It is always pitch for airspeed and power for altitude. As Langewiesche in Stick and Rudder points out, you can achieve anything short term by pitching up or down to change your altitude but that is not a stable situation. I will stick with Langewiesche says and ignore what CFIs say if anything different from this! In practical flying it has worked perfectly for me and it has made me a better pilot. I have an AoA as well which is nice to have and definitely has some benefits in high work load situations.

[Immelman]

Hey! I resemble that remark!. Actually, as a light aircraft owner and with an AoA installed, I have begun to see the"light". That said;

My conclusion, "it's the man, not the machine" -- Chuck Yeager. Take a look at this video at roughly 2:15.

 

Gen Yeager's comment just made my day, right there. Know your machine!!