THE TAIL-SPIN

Evening Post, Volume CIX, Issue 43, 20 February 1930, Page 21

THE TAIL-SPIN

TERROR OF AIRMEN

CAUSE' OF DISASTER

Most people have the wrong idea of the so-called "tailspin," that condition of no control into which it is possible for the best of pilots to have his aeroplane go, suddenly and without warning. H. B. Miller tells readers of the "Scientific American" (N.Y.) in a recent issue of that journal, just what v "tailspin" really is and how it occurs. "The 'tailspiu' is not necessarily dangerous, and is preventable," writes Lieutenant Miller.

An observer of the so-called "tailspin," had he a knowledge o£ aeronautics, would notice two peculiarities of the "dive," wo are told; first/ that immediately preceding the disaster, the nose o£ the 'plaue rose abruptly, and, secondly, that the ship ■ifcer. began to rotate either right or lett Alrfit ivs longitudinal axis. These symptoms show clearly that the crash was caused by a "spin." The original name for this manoeuvre was the "tailspin." This is a misnomer. People are led to believe that the tail ot the 'plane is downward during the spin. This name was derived from the fact that •when the 'plane is in this condition of no control," the tail of the 'plane whirls dizzily around the engine end. The name "spinning nose dive" is more indicative of the ship's true action. During the spin, the nose of the plane is down about 70tleg below the horizontal. The 'plane then spins.or whirls around a vertical axis which usually intersects the ship between. the pilot and the engine. Sometimes, however, this axis is projected a considerable distance forward ot the 'plane. Thus, a flat projection or the 'plane's spinning area may be quite large. It resembles closely the whirling descent of a maple leaf. . Aeroplanes are supported during flight by the reaction on their wing surlaces ot the passing air currents. These currents are created by pulling the 'plane forward through the air by means of a power plant operating a propeller. Gravity may be used for the same purpose by gliding-the 'plane. Altitude, o£ course, must be sacrificed in this case. An aeroplane must move forward at more than a certain speed to maintain itself in the air. < The minimum speed at which any type of 'plane will support itself m the an is called its "stalling speed." It the speed of the 'plane is reduced below this Critical or stalling speed, it will fall^ like any object that is heavier than air. Due to the peculiar arrangement of wing and tail surfaces, it rotates as it falls. This is the 'Toss of flying speed is brought about in various ways. Generally, it is a result of climbing the 'plane too steeply. The encine may not have sufficient power to lull the Wo forward at flying speed at this extreme climbing angle. Or perhaps the t>ilot is climbing his ship to the utmost! but still at flying speed. Suppose the engine fails for any one of a dozen reasons With no power to pull it forward at this steep angle, the 'plane immediately loses its slight safety factor of forward speed. It whips off into a spin before the pilot is able to nose over in.order to pick up flying speed for a sate glide. These two conditions cause practically all crashes on the take-off. . ■_ The cool-headed and proficient flyer keeps his-ship's nose low until lie has gathered safe flying speed. ,Theji,and only then, does he begin to gam altitude. If his engines should cut out, he has sutficient surplus speed to place his ship in a' safe glide preparatory to landing. Every 'plane has a definite glide ratio. The average ship will have a ratio, of approximately seven to one. .In other words for every foot ot altitude the 'plane has, it will glide forward seven feet If the 'plane is 100 feet in the air, 'it will glide to a point 700 feet away, providing, of course, that there is no wind. The glide of a power-operated plane cannot be "stretched." That is, it can glide only a certain horizontal distance lor a. riven altitude. If the engine is stopped while in the air, the 'plane can land no farther away than the point where his safe gliding angle intersects the ground. It is unfortunate if he is too tar away from a good field. THE SAFETY RANGE. Suppose the novice aviator is in a 'plane havine a glide ratio of seven to one. lie is at an altitude of 100 feet with his propeller stopped. The only good neld .is •900 feet away. In an effort to force the 'plane to glide farther than it actually, can, he pulls the nose of his ship higher and higher in order to flatten out the glide and thus reach the field. Eventually he will lose flying speed, and spin to the ground. This condition of flight provides practically all the crashes during a landing when "the 'plane suddenly dived to the Another prolific cause of spins is the "skidding turn" at a low altitude. A ■'plane must be banked m proportion to the radius of its turu. A blindfolded passenger would be unaware of ii properly executed turn. If a 'plane is not banked sufficiently, it will skid around a turn exactly as a swiftly moving automobile skids outwardly around a sharp corner. As the 'plane skids it presents a projected area of its fuselage broadside to the direction of flight. This sudden resistance causes -the 'plane.to lose part of its forward speed. I£ this condition is aggravated the 'plane will lose flying speed and lall oil into a spin. ■ These, in short, are the causes ot most accidental spins—and crashes. Since all this is known, why doesn't the pilot watch his speed carefully? The landing and takeoff period of flight is a busy one for the pilot. His attention is on many different things at once. He must watch closely for other 'planes and obstructions. The result is that he may not observe the flying speed of his ship closely enough. Shortly after the war the favourite and most dangerous stunt of aviators was the "chandelle." This is an extreme climbing turn from a take-off. The list of pilots who lost flying speed and "spun" in doing this unnecessary manoeuvre is long, indeed. It is forbidden at all regulated airports. A straight steep climbing take-off is nearly as dangerous, and equally useMost newly-hatched pilots are obsessed with the necessity of showing off their recently developed skill to the admiring throngs. It is much safer to observe the skill of these new pilots from the ground than from their rear cockpits. The adjective "fatal" has been unconsciously attached to the word "spin." Spins are dangerous under an altitude of 500 feet, because it usually takes ■ several hundred feet in which, to recover control of the 'plane. ' This results in the axiom that the first 500 feet is.the most dangerous part of flying. This is true for the untrained pilot. An experienced pilot will not allow the 'plane to approach a stalled conditioii. TRAINING FOR TROUBLE, The training o£ all aviators should cover ■the spin thoroughly. The student should be.placed in them often until'he'can unconsciously recover from them. He should be taught the warning signals that accompany a stall. They are so numerous that a pilot must bo absent-minded, iudeed, who does not heed them and take action. When flying, the interplane brace wires have a clear whistling sound. The 'plane is stable, and the pilot, through his control stick, can feel a distinct air pressure on the control surfaces. In addition, here is generally an airspeed meter to give him his actual speed through the air. When the 'plane begins to approach a stalling point the wires no longer sing merrily—the old saying is that "either the wires or the angels will sing to you!". No longer is the ship a steady platform. It shakes and trembles. The controls are sloppy and loose. No air pressure can be felt on them. The s^vly moving ship no longer responds readily to the controls. The airspeed meter will indicate clearly a dangerous flying speed. All these warnings fairly shout out to the pilot. He who tails to interpret them correctly is improperly trained or indoctrinated. In either case he is a menace to the further development of aviation, and should not be permitted to fly.

For the properly-trained pilot, recovery from a spin is very easy. He simply neutralises the controls and throttles down the engine. To come out quicker, he dives the ship and applies the rudder opposite to the direction of the spin.

Various devices aye being developed to do away with this danger. The success of these inventions has been varied, and the final mechanical solution of the problem Has not been reached as yef;, T(W J»ostj

efficient method of eliminating this menace is the thorough training of pilots. The anxious mother who admonished her eon that if ho was determined to be an aviator he must lly slowly and low, did not know her aeroplanes. No one has ever gone into a spin from too much flying speed. Beware of your fricud who wants to take you up to prove that he can fly. Is he a good flyer?' Certainly, for didn't he solo, just last month in the remarkable time of two hours and thirty-five minutes' dual instruction! Let him thrill someone else. Instead, drive out to some legitimate and 'well-managed airport. Take your flight with a recognised organisation. Enjoy your ride with Hie assurance that the company can afford to hire only good pilots. i