HANGARS AND AEROPLANES AS SEEN BY A PILOT whose machine is climbing after a take-off from Heston Airport, Middlesex. The aeroplane is to the right of the buildings because taking-off directly over obstacles is avoided as far as possible. Wind direction is indicated by a wind-stocking flying at the top of a short mast. On the ground to the right of the buildings is the special clock which is easily read by pilots in the air.
WHEN his initial training in the air is completed and he has learnt how to turn an aeroplane, the flying pupil is ready to proceed with training in circuits. The circuit is a most important part of his tuition. It is not a separate item such as turns or gliding; it combines all that the pupil has already learnt and a great deal more besides. The circuit begins with taxying and ends with a landing; it is really a complete short flight.
A circuit may be divided into four sections: taxying, take-off, approach and landing, and they follow one another in this order. The instructor will deal with each section separately; but, as soon as the pupil has grasped one section, the instructor will pass on to the next. This is because the pupil can practise the preceding section or sections while learning the next. For instance, while learning about the take-off, the pupil can practise taxying, because a certain amount of taxying has to be carried out between each landing and the next take-off. Taxying is the moving of an aeroplane on the ground. Turning an aeroplane while taxying can be achieved in three ways, according to the design of the particular aeroplane. In most trainers it is carried out by the use of the flying controls - the rudder, ailerons and elevators. The rudder, however, is the most important in taxying. The second method - applicable to some machines - is to have a steerable tail skid working in conjunction with the rudder for purposes of manoeuvring. The third method of steering an aeroplane is by wheel brakes.
If the machine is one without a steer-able tail skid or wheel brakes, the procedure for taxying is as follows: The instructor and pupil take their places in the aeroplane, the engine is started and the chocks are removed. The pupil is now told to open the throttle slowly until the machine begins to move, and then to keep it straight with the rudder.
The pupil will soon find that coarse use of the rudder is necessary because its turning effect is entirely dependent on the stream of air provided by the propeller. To turn to the right the rudder is put full right and to turn to the left it is put full left. At the same time it is necessary to open up the engine more. As soon as the aeroplane begins to turn, the throttle may be closed a little and some of the rudder taken off. Turns should not be sharp. Speed must be kept low in all taxying.
The turn may be assisted, if the machine is moving across wind or into the wind, by putting the stick over to the opposite-side of the direction of turn. In a left turn the stick is put to the right, the left aileron goes down and acts as a wind brake on the left of the machine, thus helping it to turn.
When the machine is being taxied with the wind this effect will not occur. It may even be better in this instance to put the stick over to the side to which the turn is to be made. An important point when taxying with the wind is that the stick should be put forward. This lowers the elevators and the following wind then presses the tail on to the ground. If the stick were not put forward, or if it were held back a little, the wind might tend to lift the tail and tip the machine on to its nose. In a machine with a steerable tail skid, the stick should be put forward for the same reason when taxying down wind. Generally, however, taxying with this type of skid will be easier. The use of the ailerons is not necessary, and movements of the rudder will be considerably smaller. In no circumstances will the pupil be allowed to try to move the rudder until the machine is well under way. To do so might injure the rudder-control mechanism.
THE IMPORTANT POINTS OF A CIRCUIT are illustrated in this diagram. To emphasize these points, the size of the aeroplane has been exaggerated. Rules of the air require that the machine shall maintain a straight glide for at least 300 yards before reaching the boundary of the aerodrome. There is no objection to the final turn into wind being made at a greater distance than 300 yards.
Before a pupil attempts to taxi a machine with wheel brakes, the brake control mechanism is explained to him. Generally there is a hand lever which, when pulled back, puts on the brakes of both wheels equally; moreover, when the rudder is moved it puts the brakes on independently. To turn to the right, right rudder is applied. This brakes the right wheel and the aeroplane will turn easily, though a little extra throttle will probably be required. The hand brake lever is put in the off position before taxying.
At first the pupil will think an aeroplane is clumsy when it is moving on the ground. But, after all, it is not a car, and is not meant to travel quickly when on the ground. Fast taxying is usually bad airmanship.
The pupil is now ready to learn about the take-off. This will require all his concentration at first, but is not difficult.
First, the meaning of air speed has to be grasped. The air speed of a machine, when the wind is blowing against it, is the sum of its own speed over the ground and the speed of the wind. When the wind is blowing with the machine, the air speed is the machine’s own speed less the speed of the wind. When there is no wind, the air speed is the same as the ground speed.
Take-off into Wind
The aeroplane must attain a certain air speed - say 45 miles an hour - before it can fly. If there is no wind, it must move over the ground at 45 miles an hour before it can take off. If there is a wind, the take-off is always made with the machine facing into wind. If the wind is blowing at 15 miles an hour, the aeroplane will attain its air speed of 45 miles an hour when it is moving over the ground at only 30 miles an hour. In the instance quoted, if the machine took off with the wind it would need a ground speed of 60 miles an hour; a longer take-off run would thus be necessary, there would be more strain on the undercarriage, and faulty flying would be more likely to prove dangerous.
Before a take-off the machine is taxied into a position facing, the wind, and near to the edge of the aerodrome so that the longest possible run into wind is available. Should the engine cut out just after the take-off, the pilot will then have the best chance of landing again before the boundary of the aerodrome is reached.
The pupil will learn to do three things before beginning to take off. He will see that the tail trimming lever is forward, he will look ahead to see that no other machines are in his path, and he will look up in the air behind him to see that no other machine is coming in to land. If another machine is about to land the pupil’s duty is to wait for it before moving forward.
The positions of flaps and brake levers will also need checking on machines fitted with them. On some machines with flaps, these are kept in the up position for the take-off, and in others - such as the Miles Whitney Straight - they are put into an intermediate position. To take off, the throttle is pushed right forward and kept pushed forward. At the same time the stick also is put right forward. As soon as the aeroplane has gathered a little speed the tail will rise. As the tail rises the stick is allowed to come back to the position at which the aeroplane is in a level attitude. If the stick were kept forward, the tail would rise higher and higher until the aeroplane went over on to its nose. On the first few take-offs, the instructor will tell the pupil when the tail is at the correct height; after that the pupil should be able to judge the height for himself.
While the machine is running over the ground before gaining flying speed, it must be kept level in a lateral direction by the use of the ailerons. The pilot must also keep it on a straight path, by aiming at some point on the aerodrome boundary, and making use of the rudder. At first, coarse use of the rudder will be required, but less and less rudder will be needed to keep the machine straight as speed is picked up.
Most biplane trainers lift themselves off the ground if the tail is at the right height. With monoplanes it is generally necessary to ease the stick back slightly when sufficient speed has been attained. When the machine is airborne it is kept level until it is travelling fast enough to permit the best climbing angle to be taken up by the pilot.
Climbing is continued until a height of 200-300 feet is reached. At this height the machine is put level and the throttle closed until normal cruising revolutions are reached. Then a wide turn is made to bring the machine down-wind. The instructor will now tell the pupil to fly straight until he is well to the leeward of the aerodrome, maintaining a gentle climb the whole time. Here the instructor will take over and land the aeroplane.
After two or three attempts, the pupil will be able to make a passable take-off, and instruction in the approach can be begun. The approach in modern conditions is somewhat different from that taught a few years ago. Then, S turns to lose height while approaching the aerodrome were permitted; now, they are barred at public aerodromes because several machines may be gliding in at the same time. Further, the use of the engine while gliding in is quite common today, especially with large commercial machines. The pupil will be taught the following procedure.
When the machine is 300-400 yards to the lee side of the aerodrome, it is turned across wind, the throttle closed, the tail-trimming device pulled right back, and the normal gliding angle taken up. At a height that will permit the aeroplane to land about one-third the way across the aerodrome, a gliding turn into wind is made. A steady glide is then maintained, dead into wind, until the machine is 20 feet from the ground, at which height the landing is begun.
It is one of the rules of air traffic that the final turn into wind shall be made at a distance from the aerodrome boundary of not less than 300 yards, and that the machine shall thereafter be kept straight. Considerable practice is needed before the right height at which to make the final turn can be accurately judged.
Allowance has to be made for the strength of the wind because the stronger the wind the smaller the distance covered by an aeroplane for a given loss of height. The pupil should always make the turn into wind at such a height that he is sure he can reach the aerodrome without using his engine. This makes good practice for a forced landing that might be made necessary by engine failure. At this stage of his training the pupil cannot be allowed to emulate the type of landing so often made by commercial pilots in which the engine is used during the final straight approach.
A MILES HAWK MONOPLANE climbing up from Reading Aerodrome, Berkshire. The name of the aerodrome is visible in large letters on the ground. The names of commercial aerodromes are marked in this manner with chalk or concrete letters let into the turf. In this picture the pilot is flying solo, a stage which is soon reached once the pupil is thoroughly proficient in the making of circuits from the point of taxying into position to the completion of the landing.
In making sure that he has sufficient height to clear the boundary of the aerodrome, a pilot may find he is coming in too high on his final glide. This means that he will land so far down the aerodrome that the machine will be in danger of running into the far boundary. The term “overshooting” is applied to this situation. The pupil will be taught to sideslip in such circumstances.
The sideslip is a means of losing height rapidly without gaining forward speed. To put the machine in a steeper than normal glide will not help when overshooting, because speed will be gained; and on getting near the ground the machine will have to be kept level for a long way to lose this extra speed before a landing can be begun. A normal sideslip is achieved by putting on bank in either direction. Then, to prevent the nose from dropping, opposite rudder is applied. In a sideslip to the left, right rudder is used. When gliding into wind, it is best to begin to apply the rudder first, so that the nose of the machine slews out of wind a little. To stop such a sideslip, the nose of the machine is brought back into wind by use of the rudder and the controls are then centred. While gliding across wind it may become obvious to the pilot that he will glide too far towards the right of the aerodrome before he is low enough to make his final turn without risk of overshooting. In this instance he may sideslip while gliding across wind. To do this, bank is applied first, and then opposite rudder to keep the nose from getting too low.
An advantage of sideslipping in this position is that the sideslip can be converted into the final turn into wind. In a left-hand circuit - and circuits are generally left-handed - this sideslip will be to the left. By changing from the right rudder of the sideslip to left rudder, the sideslip will change to a left-hand turn into wind. By suitably adjusting the amount of left rudder, a sideslipping turn may be made which will lose further height.
A Perfect Landing
If the machine has flaps these may be put down while gliding across wind or while gliding into wind. Once they are put down they should be kept down until the aeroplane has landed.
Landing an aeroplane is the least easy part of learning to fly. Many pupils reach this stage quickly and then find that they “stick” at landings for a comparatively long time. The pupil should not let this worry him if it should occur. Perseverance will produce the judgment needed to enable him to get the tail down at the right moment to make a good landing. In a perfect landing the aeroplane is stalled an inch or two above the ground with the wheels and tail skid on the same level. It then runs on to the ground with no possibility of bouncing up again. To achieve such a landing the final glide into wind is continued steadily as explained for the approach, until the aeroplane is about twenty feet above the ground.
At this height a gradual easing back of the stick is begun. The movement has to be extremely slight at first, or the aeroplane will level out and then start to rise again. The gentle easing back of the stick is continued until the aeroplane is about a foot above the ground and gliding along level with the turf. Almost immediately the machine begins to drop on to the ground, and this is prevented by pulling back the stick more and more.
This pulling back of the stick increases the angle of incidence of the wings and so provides greater lift for a short time. This lift holds the machine off the ground until it eventually stalls. The aeroplane still has a certain amount of forward speed after it has touched down and has to be kept straight by coarse use of the rudder until a standstill is reached. If the aircraft has brakes, these may be gently applied to shorten the run.
Although the easing back of the stick during the landing is a continuous and progressively faster movement in an ideal landing, the pupil will be taught to make distinctly separate movements at first. Looking about thirty yards ahead, over one side of the machine, the pupil will find that the grass suddenly begins to become distinct.
DE HAVILLAND HORNET MOTH TWO-SEATER in which the seats are arranged side by side in a cabin. This machine is popular with private owners and is suitable for training purposes. It is equipped with wheel brakes. The engine is a Gipsy Major, giving 130 horse-power and providing a top speed at sea level of over 120 miles an hour. The indicated stalling speed is low, being 40 miles an hour.
At this point the instructor says “Check”, over the telephones, and the slightest backward movement of the stick is required. At about ten feet the pupil will be told to “check” again. This time a little bigger movement is required. Soon afterwards the instructor will repeat “Back” three or four times, with increasing emphasis to indicate bigger and bigger movements of the stick. The stick should be as far back as it will go when the machine touches down.
During early landing practice the pupil will make every kind of mistake possible. This is inevitable until he begins to gain a good judgment of the height of the machine, its speed and angle in relation to the ground. If the stick is pulled back too far at first, the machine will rise again, and then try to stall ten or twenty feet above the ground. The instructor will prevent it from doing so by opening up the engine. Another fault in landing is stalling the machine on a level keel but a foot or two above the ground. It then drops heavily, and the undercarriage is in danger of being damaged. A third fault is not getting the stick back soon enough or sufficiently. The machine touches the ground wheels first while it still has flying speed, and may bounce into the air again.
During the final glide, before beginning to land, the pupil is taught to check that he is dead into wind. If he is not, he will be drifting to one side or the other. Drift can be noted by looking at the ground, first over one side of the aeroplane and then over the other. The gentle turn, to bring the machine properly into wind if it is drifting, must be made properly, with the application of bank as well as rudder. There is a tendency for a pupil to want to make this small correcting turn by using the rudder only.
Later in his tuition, the pupil will be taught how to turn a landing which starts badly into a good one. At his present stage of progress, however, if he has any doubts about a landing, the correct thing to do is to open the throttle fully, make another circuit and begin the landing over again. In these circumstances, if the machine is fitted with flaps, no attempt may be made to raise them until a good height and speed are reached.
After his first few lessons in landing, the pupil will do all the flying of each circuit right from the point where taxying begins until the landing is completed. He will not be prompted in any way by the instructor. He is now reaching a stage when he has to rely absolutely on his own judgment. The instructor will intervene only if a dangerous mistake is made. Other mistakes are pointed out on the ground after the pupil has landed.
Except for an occasional interval to practise steep turns or to provide some other change, the whole of the pupil’s lessons are now devoted to circuits. He will get to know every building, field and haystack in the neighbourhood of the aerodrome. He must, however, avoid picking out landmarks over which to make his final turns before landing. The wind may change while circuits are being practised and to fly by landmarks might cause incorrectly performed out-of-wind landings to be attempted.
HOW AN AERODROME WOULD LOOK TO A PILOT gliding across wind before turning into wind for a landing. The height at which the turn into wind is made is largely dependent on the strength of the wind. The stronger the wind the higher the machine should be when the final turn is made. When gliding in a strong wind, an aeroplane covers less ground in losing a certain height than it would in a gentle wind. The name of this Kentish aerodrome -Lympne - is visible on the ground.