PPRuNe Forums - View Single Post - Throttle for speed, or stick for speed?
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Old 16th Feb 2005, 21:49
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MLS-12D
 
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Who said anything about being at the stall?
Well, fair enough: you only said "low and slow". But I presumed that you meant conditions were approaching critical ... if not, there is little point in the discussion, since otherwise anyone can muddle through with the wrong control movements, and proper training is essentially unnecessary.

ask your teenage kid what he/she thinks you should do if slow in an aeroplane!
That is not a reliable source, far less a definite one! Your comment reminds me of the following passage in Langewiesche, p.148:

You know how the controls are labled on an alarm clock or on a kitchen stove. These are arrows marked "on" and "off", "slow" or "fast", "hot" or "cold", telling the customer exactly which way to move what control in order to get what result. Well – here is an idea for one of those unflyable days at the airport; how would you label an airplane’s elevator and throttle?

Your kid brother, knowing what every boy knows about flying, will call this one easy. He will label the throttle “fast” and “slow”. Does not the throttle do to the airplane’s motor exactly what the gas pedal does to an automobile motor? And he will label the stick “up” and “down”. Does not pulling back on the stick make the airplane go up and down? It is only common sense.

Unfortunately, though, the present conventional airplane is not a common-sense contraption; and this labeling of its controls is wrong. It is wrong not only “in theory”; it is wrong also in practice. It is dead wrong; if you really did try to use the controls that way, you would kill yourself. Most fatal airplane crashes happen precisely because the pilot has the controls so labelled in his mind and tries to "elevate" himself, or at least hold himself up, by pulling back desperately on the so-called "elevator". An airplane will not go up, nor will it stay up, simply because the pilot pulls the stick back. In fact, in all the more critical situations of flight, it is all too likely to do exactly the contrary! In the glide, for instance, the farther the stick is held back, the more steeply downward will the flight path be - even though the nose may not point down steeply. In a stall or spin, the ship is dropping precisely just because the stick is held too far back! As for the throttle's being a speed control, the fact is that you can stall with the throttle wide open! Most fatal stall or spin accidents do occur with the engine running nicely at cruising throttle! In fact, when the throttle is open and the propellor blast is hitting the tail, the average airplane actually wants to fly more slowly, and will stall more readily, then with power off! In short, the elevator does not make the airplane go up or down, and the throttle does not make it go fast or slow, and your kid brother is wrong.
A similar passage appears in Leighton Collins, Takeoffs and Landings (1981), pp. 7 and 8:

Elevator versus Throttle

As you know, in recent years there has been a lot of discussion about what controls airspeed and what controls altitude. By FAA ukase (sic) we are required to think, or at least to say on our writtens, that the elevator controls altitude and the throttle controls airspeed.

I think this is a horribly dangerous concept when the chips are down, because it can cause pilots to bull back on the stick to go up, or, after an engine failure, to stay up. It is instinctive for people to think in terms of pulling back on the stick to climb or maintain altitude, because it is so logical.

The best example I know of this universal impulse came a few years back. My friend, little Helen Langewiesche, had been given a spin demonstration before soloing a glider. One evening after dinner with Helen and her test-pilot/author, Wolfgang, I asked her what she would do with the stick if ever she found herself nose-down and starting to autoroate. Her answer: "Why dummy, I'd pull the stick back all the way, because if you don't get the nose pointed up instead of down, you're going to fly into the ground". Stick and Rudder, over on the other side of the fireplace, became rigid. I paled. In the ensuing silence, Helen added, "Oh, well, yes, first it is necessary to lower the nose to get some speed, and then you can get headed away from the ground." In short, she knew better, but her initial statement revealed a universal instinct that has to be trained out of people.

A proper concept of airspeed and altitude control is important in thinking about takesoffs and landings, because these are low-altitude operations, and virtually all stall/spin/mush accidents begin close to pattern altitude. And those who, ground-shy, instinctively pull the stick back to gain or maintain altitude, go down.
Personally, I think that Langewiesche (Wolfgang, not Helen!) knew, oh, roughly 1,000% more about airmanship than you and I put together, and Chapter 9 in his classic text is definitive on the topic under discussion.
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