THE MAXIMUM SPEED of the Cub monoplane is 87 miles an hour; its landing speed is about 30 miles an hour. It is a high-wing braced monoplane with a forty horse-power four-cylinder engine of the horizontally opposed type. A split undercarriage is fitted and the machine is exceptionally easy to fly. Only a short take-off and landing run are required; thus the aeroplane is suitable for flying from small fields.
CONSIDERABLE numbers of light aeroplanes are sold annually in the United States of America. The long distances between many of the towns there make aeroplane travel an economical proposition, and most of the machines are bought privately. Farmers and others who may be situated many miles from a railway particularly appreciate the convenience of travelling in their own aero-planes.
One of the most popular of the light aeroplanes is the Cub, known until recently as the Taylor Cub. It is now manufactured by the Piper Aircraft Corporation of Pennsylvania, USA. These aircraft are built in large numbers and a number of Cubs have been bought by private owners and by flying clubs in Great Britain.
The rapid increase in the popularity of the Cub is illustrated by the following figures. In 1935 211 “Cubs” were produced. In 1936 an improved model was introduced; it was called the “New Cub”. Of these 550 were produced in 1936 and 727 in 1937. The 1938 model is sometimes called the “New Silver Cub”.
Unlike many of the continental light aeroplanes which have twin-cylinder engines, the Cub is fitted with a four-cylinder engine. In 1935 some models were supplied with a three-cylinder engine, the Szekely S.R. 3-35 which developed 35 horse-power.
The engine fitted by the company in the 1938 Cubs is a 40 horse-power Continental engine made by the Continental Motors Corporation of Detroit, Michigan, USA. This engine is described later in this chapter. A new Continental engine of 50 horse-power has recently been introduced. This is a similar type of engine to that fitted to the Cubs, and Cubs with this new 50 horse-power engine will be introduced in the future.
The Cub is an aeroplane of orthodox appearance and carries two people. It is in no way a “freak”, a term which might be applied correctly to some of the ultra-lightweight aeroplanes introduced in recent years. Economy and ease of flying are outstanding features. So confident are the manufacturers of the ability of the normal person to fly the Cub that in the United States of America a course of instruction in flying the machine is included in the price if desired by the buyer.
The Cub is a high-wing cabin monoplane, the two seats being arranged one behind the other. The visibility is good from both seats; it is possible to fly the machine from either seat when two persons are being carried. For this purpose dual controls are therefore provided.
On occasions when there is only one person in the aircraft, the back seat is used because the front seat is rather far forward in relation to the centre of gravity of the aircraft. If the pilot sat in the front seat when flying by himself, there might be a tendency for the aircraft to tip up on to its nose if a bad landing were made. A feature of special interest is that floats or skis may be interchanged with the wheel undercarriage. Thus the Cub may be used from tracts of water in summer and winter. Precautions are taken in the production of the aircraft to protect all metal parts, so that when the aircraft is used as a floatplane it may alight on the sea without fear of trouble from corrosion.
The airframe, except for the wing spars, is built of metal. More than 500 feet of seamless chrome-molybdenum steel tubing and carbon steel tubing are used in each Cub. The tailplane, to which the elevators are attached, is adjustable to provide fore and aft trimming. A lever to make the necessary adjustments is provided in the cabin.
The undercarriage is of the split type, the space between the main struts of which is covered in with fabric. Unusual strength is given to the undercarriage because it is realized that an inexpensive light aeroplane of this type will be used largely by pilots with little experience. The fuselage and wings are fabric-covered. The wings are supported above the fuselage by a system of steel-tube struts which form the framework of the cabin. This system is so designed that a large space may be made available for getting in and out of the cabin.
The lower half of the starboard side of the cabin hinges downwards; the upper half hinges upwards and is held by a clip to the right-hand wing. The overall length of the aircraft is 22 ft 5-in. The wing span is 35 ft 2½-in. and the overall height 6 ft 8-in. The chord of the wings is 5 ft 3-in, giving a total wing area of 178 square feet. The power loading is as much as 25 pounds for each horse-power, but this is counterbalanced by the light wing loading of under six pounds per square foot.
The useful load of the aircraft is 407 lb, so that even with two people of more than average weight on board, ample luggage may be carried. A baggage compartment 10-in by 10-in by 24-in is provided behind the back seat.
To a pilot familiar with the British type of training aircraft, the first impression of the Cub in the air is that it may be flown in a “lazy” manner; the control movements for any particular manoeuvre may be made in a leisurely way. It is this aspect of the aircraft which makes it so safe to fly. Liberties may be taken with the Cub and cause nothing worse than unpolished flying.
This aeroplane can be spun by an expert pilot, but it must be forced into the spin, if pressure is removed from either the stick or the rudder-bar during a spin the aeroplane automatically comes out of the spin. Landings are not difficult, mainly because they are carried out at a speed of about 30 miles an hour, but partly because the aircraft has little tendency to bounce or balloon. The angle of glide seems a little faster during the glide than in most aeroplanes with light wing loading. The gliding ratio is 10 to 1.
Service Ceiling 12,000 Feet
The maximum speed is 87 miles an hour at sea level; the cruising speed is 74 miles an hour. An eight-gallons petrol tank is fitted and this gives a range of 210 miles. The initial rate of climb is 450 feet a minute, but becomes less as height increases. The service ceiling is 12,000 feet.
The take-off run is 125 feet and the landing run 100 feet. Effective side-slips can be performed, although, if they are made at all steep, they tend to become crab sideslips. The stall is not obnoxious. If the aeroplane is held in a stall it performs a series of dives ending with the nose high as speed is gained and the elevators become effective again.
It is possible to fly without discomfort with the upper half of the entrance on the starboard side raised. This is a point that will be appreciated by those who prefer an open machine during hot weather.
Although the Cub is supplied in Great Britain with an instrument-board type of air speed indicator, this is not a standard fitting in the United States. The reason for this is that far more importance is placed on flying by “feel” in the United States than in Great Britain, so far as light aircraft are concerned. The Continental engine fitted to the Cub is a flat four. The cylinders lie horizontally, two on either side. The order in which the cylinders fire is as follows: First the right-hand back cylinder (looking in the direction in which the aircraft flies), then the left-hand back cylinder. The right-hand front cylinder follows and finally the left-hand front cylinder.
TWO SEATS ARE PROVIDED in the cabin, one behind the other. Access to the cabin is obtained from the starboard side, which opens up in two sections. One half hinges downwards; the other hinges upwards and is held in the open position by a clip. Dual controls are provided. The aircraft is normally flown from the back seat when there is only one person in the cabin.
The maximum revolutions a minute that the engine should be allowed to do is 2,700; the cruising revolutions are 2,250 a minute. Fuel with an octane-content number of 72 is intended to be used. This is equivalent to the average British No. 1 petrol. Every 250 hours the engine requires a top overhaul; major overhauls have to be carried out every 500 hours.
The cylinders have a bore of 3⅛-in and a stroke of 3¾-in. The compression ratio is 5·25 to 1. Dual ignition systems are fitted.
The Cub model described above is known as the J 3, or Sports Cub. There is another model made which is different in one or two details. This second model is called the J 2, or Cub Trainer. In this model the celluloid side panels may be removed to convert the aircraft into an open model for hot weather use. Another feature where the J 2 differs from the J 3 is the rudder, which is smaller on the J 2. This is a logical difference for a training machine, because most people when learning to fly are inclined to use too much rudder for various flying manoeuvres.
In Great Britain Cubs are used for training purposes at the County Flying Club, Leicester. It is significant that the inclusive rate offered by this club for training up to the pilot’s A licence is one of the lowest in the country.
A Scaled-Down Version
Early in 1938 there were six privately owned Cubs in Great Britain. One of these belongs to Charles Gardner, who won the King’s Cup Race in 1936 and 1937, and who is having skis and floats provided. Another is used by a farmer near Coventry, Warwickshire, who flies the aeroplane from his own fields.
As a high-wing braced monoplane, the Cub follows a popular practice in American private-owner types of aircraft. The Cub might be described as a scaled-down version of the general design that has been used considerably for the larger types of aircraft. The view is good from the cabin, a feature which is partly due to the high-wing design.
The performance is scaled down at the same time as the dimensions, but even so it can be impressive when the aircraft is flown solo. In these conditions the take-off and climb are rapid and the stall is even more gentle than it is with two people in the aeroplane.
Cable operation is used for the ailerons, which are of narrow chord. They are fitted in to the trailing edges of the wings and do not run right to the ends of the wings. Rubber cord is used for springing in the undercarriage. Normally a tail skid is fitted, but a steerable tail wheel may be provided as one of the extras which are available.
The front controls may be removed when it is desired to move the controls out of the way of a passenger. On normal cross-country runs petrol consumption is at the rate of approximately two and a half gallons an hour and one-third of a pint of oil is also used each hour. The oil sump holds a gallon of oil.
Among the extras listed for the Cub is a special compact parachute. Modern aeroplanes are so safe to fly and so soundly built that a safeguard of this nature is not normally necessary, but for those who fly over inhospitable country the parachute is certainly an asset.
WELDLESS TUBES are used to build up the fuselage of the Cub. Five hundred feet of such tubing are used in each aircraft. The fuselage and wings are fabric-covered. The wings are carried on top of the fuselage by a system of tubular struts which form the frame for the cabin. The baggage container, placed behind the back seat, can be seen in position in this photograph of a stripped fuselage.