Basics of Aircraft Recognition

Like people's faces and figures, every aircraft and helicopter has its own characteristics. It may have one engine and straight wings; four engines and swept wings; a fat fuselage; a triangular wing; a sailplane on top of the fin; or, in the case of a helicopter, one or two rotors.

The basic structure of an aircraft has to be studied from the outset. Every powered flying machine (other than helicopters) has some wing form, a fuselage and a tail structure, the last mentioned having either a horizontal stabiliser and a fin, or a fin alone (as in the case of some delta -wing designs such as the Mirage and Concorde). Every wing, fuselage and tail structure differs in some respect from another, as do the engine installations and air intakes, be they for gas turbines or piston engines. It is the combination of these features with individual characteristics that makes up an aircraft's total shape. Knowledge of such shapes is the essence of recognition.

The same theory applies to helicopters, except that wings appear only occasionally in stub form, tail structures consist of rear rotors and some miniature tails, and the main rotor(s) dominate the shape.

The best way for the beginner to use this book is to look first at totally different types, say the Mirage fighter and the Boeing 747 airliner, or the Jaguar ground- attack aircraft and Chinook twin rotor helicopter. In the first case, a single engined delta wing fighter with the engine in the fuselage just cannot resemble a giant 385-seater with four jets slung under the wings. In the second case, the swept-wing Jaguar hardly compares with the Chinook, with its squat, boxlike fuselage and twin overhead rotors.

This process should be continued at random, selecting from the different sub-sections of the book.  For an understanding of aviation terminology the glossary of terms and abbreviations book can be used.

The second stage is for the reader to look at two of the aircraft in each sub-section which are similar in general layout but very different in detail characteristics. Take, for instance, the Corsair II and the Lightning in Section 1. The two wing shapes immediately strike the eye: that of the Corsair is broad in chord and moderately swept back, while the Lightning's resembles a triangle with two triangular notches cut out at the roots. The Corsair fuselage is dumpy, with a distinctive "pimple" above the nose intake. The Lightning, on the other hand, has a circular intake with a pointed centre body. Unlike the Corsair, with its simple engine and exhaust arrangement, the Lightning has two engines mounted one above the other in the fuselage and exhausting through twin afterburning jet pipes. Finally, the fin of the Corsair tapers to what looks like a curved top, while the Lightning's fin is much broader and cut sharply across the top.

After several excursions through the pages to see how shapes differ markedly or are superficially similar, the student should select his basic first 30 aircraft. If he is a member of a military or paramilitary force, he can choose the friendly and unfriendly types which he is most likely to encounter.

A mixed first 30 could consist of the following:

For helicopters an initial eight could be:

The student who wants to devise his own programme could well make his first selection from the types which fly from the nearest civil or military airfield, or both. After the first 30, a further 30 can be chosen, and so on. After the student has mastered his first 30 aircraft, he will be able to apply his self-acquired training to any types of his choice.

Throughout, the recognition of an aircraft must involve a total impression of the shape, but with certain distinctive elements borne in mind. When any aircraft appears it must be watched right across the sky so that it can be viewed from every angle.

In the air, the head-on view of an F-15 fighter looks very different to a side or plan view, possibly leading to confusion with the Soviet Foxbat. Aircraft viewed from the rear, going away, also often provide problems, as with the Mirage and Viggen. Particularly difficult are the head-on and retreating views of the transports with twin and triple rear-engine layouts, not least the Soviet Crusty and Careless airliners. The Soviet Badger and Bison bombers are easily confused at a distance, when the difference in size cannot be estimated.

Helicopters require special study as, at a distance and in poor weather, their shapes tend to be ill-defined. In certain cases very detailed knowledge of outlines is needed to differentiate between types. Examples of similar outlines are the German MBB BO105 and the Hughes 500D helicopters.

The only way to progress in aircraft recognition is to "look and learn" as frequently as possible. This means not only scanning the skies but examining every photograph or drawing in newspapers and magazines and watching for aircraft on television. A scrapbook of picture cuttings and notes is an excellent way of improving the art.

When an unknown aircraft flies over, or an uncaptioned photograph appears in a journal, note its main features and consult the appropriate section in this book. The more "mental images" of different types that can be stored away, the easier recognition becomes.

Changing outline

Having learned the flying exterior of an aircraft, the effects of external items that may be attached to it require attention. Modern military aircraft carry a great variety of external "stores": missiles, rocket pods, bombs, reconnaissance pods, externally mounted guns, electronic jamming pods and auxiliary fuel tanks, to mention a few. As an example of the resulting outline change, the podded fuel tanks under the wings of a Hercules transport can, at a distance, give the impression of six engines instead of four. Radomes and other bumps or bulges on an aircraft also change the shape when viewed from different angles.

Variable-geometry or swing-wing aircraft present problems, as moving the wings from straight to fully swept changes the outline continuously.

Finally, an aircraft preparing to land can appear completely different from its normal cruising self. For instance, a Boeing 747 cruising across the sky is not the same as a 747 on the approach to an airfield with its multi-wheel undercarriage down and massive flaps extended.

To appreciate all the changing aspects of aircraft in the air, it is essential to keep watching with the eyes or, preferably, with binoculars. When there is cloud, watch where the aircraft enters and judge where it may reappear.

Viewed from above

For the military pilot, aircraft flying below or positioned on the ground are very important. The pilot's view can be very different from that of the ground observer. It takes a sharp eye to recognise a fleeting shape parked near a hangar, in a revetment, or with its nose sticking out of a shelter. Special study is needed to separate shapes on the ground from their surroundings, and camouflage makes this even more difficult.

In the air, it is easier to recognise aircraft  seen from below. From above, aircraft blend with the terrain, particularly when they are camouflaged, or have their outlines broken up by reflected light.

Contrails

At high altitude condensation of the water vapour in the exhaust gas of an aero-engine produces a "contrail", a tell tale stream of white vapour across the sky. On a clear day it is often possible to recognise the aircraft at the head of the trail, but usually binoculars are essential. When there is patchy cloud the point of entry of the contrail should be noted to find the direction of exit. Large multi-engined aircraft make several trails which usually blend into one. With a lot of experience it is possible to differentiate between certain types, but great care is needed.

Sound

Sound is very often the first indication that an aircraft or helicopter is approaching. Weather effects and the varied abilities of human ears can however make sound very misleading. It may appear to come from completely the wrong quarter, causing the observer to miss the approaching aircraft altogether. With fast aircraft, the subject may be well ahead of its noise. Sound is nevertheless important and certain basic facts can be gleaned from it. It is usually possible to differentiate between a piston engine and a jet; a turboprop is distinctive, while the beat of a helicopter rotor sounds different from the noise of a fixed-wing aircraft.

It is important to both watch and listen in order to associate sound with a particular type. A great deal of practice is needed before making snap judgments on sound alone, and even then there is a higher chance of error.

from an Air Cadet Publication edited by G King