Military Pilot Training In The Jet Age

The Jet Provost and Vampire Jet Trainer
The Hunting Percival-de Havilland Partnership. Royal Air Force adopts new all-through jet training system

With the advent of turbojet-powered fighter aircraft, it became apparent that jet-powered training-aircraft would be required to enable the new generations of pilots to be made familiar with the special handling characteristics of jet aircraft, under the direct supervision of qualified flying instructors. The quickest way to produce such a trainer is, naturally, to modify to dual control some existing single-seater aircraft but, as is to be expected, these adaptations are seldom acceptable as more than a temporary measure pending the production of aircraft designed to meet the highly specialised requirements of flying training.

A variety of jet fighters were modified to become dual advanced trainers but, at best, they suffered from the inherent difficulties associated with these conversions and, in general, they have been excessively expensive to operate.

One of the first jet advanced trainers specifically designed for the work was the de Havilland Vampire T.II which, although bearing the name .. Vampire and having a strong family resemblance to the earlier Vampires, was, in fact, an entirely new design. As a matter of historical interest the T.ll was a de Havilland private venture; an addition to the long list of successful military training aircraft provided by the British Aircraft Industry from its own resources.

The Vampire Trainer, by replacing piston engined Advanced Trainers in the pre-wings military pilot training curriculum, provided the pupil pilot with conversion to jet techniques and experiences in high-altitude, high-speed jet flying while still in the care of the flying instructor and the flying training organisation. It has proved most economical by comparison with other advanced jet trainers.

In the Royal Air Force (and later in various other air forces) the stage of training preceding the relatively advanced Vampire T. ll was filled by the Hunting Percival Provost. Although this trainer was powered by a piston engine of some 550 h.p. and was far more comprehensively equipped than the earlier elementary trainers, it possessed such docile handling qualities that ab initio training presented no problems. This private venture aircraft has proved a highly successful and popular trainer in the ab initio and basic roles.

The Provost/Vampire syllabus of some 230 flying hours was divided approximately 50 per cent. on each type. This, of course, was a great advance in that it gave the pupil about one half of his pre-wings flying in a jet trainer ; there still, however. remained the fact that during the early half of his training be was learning various techniques completely inappropriate to jet aircraft.. These techniques had to be forgotten and new ones learnt when he advanced to the vampire T II which meant that a relatively costly advanced advanced jet trainer was being used to teach the basic principles of jet flying and the real danger existed of the pupil reverting to the earlier learnt methods in emergency in jet aircraft. Many accidents to jet aircraft have been traced to this cause.

It is obvious that piston engined training in Air Forces rapidly becoming preponderantly equipped with jet-powered operational aircraft is a definite liability; nevertheless, the prospect of carrying out the entire military training syllabus in jet aircraft was at one time thought by many people to be impracticable. The turbojet engine had, from its inception, prepared to be inseparable from ultra-high performance fighting aircraft and there was considerable opposition to the idea of ab initio training on jets Hunting Percival , having experienced precisely the same kind of opposition in regard to the Provost because of its comparatively high power, weight and complexity, were convinced that their knowledge of training requirements warranted their decision to design and build an ab initio jet trainer.


The result has been the Jet Provost - yet another British private-venture trainer. - Over the past two years the -Royal Air Force has been training on the Jet Provost/Vampire sequence with outstanding success. Of fifty pupils, the large majority of whom had no previous experience whatever, forty-nine have flown solo. Thirty-five without previous experience have flown the Jet Provost solo after an average of 10 hours 10 minutes dual instruction, the shortest time being 7 hours 5 minutes. Fourteen, with varying amounts of previous experience on light aircraft, averaged 7 hours 25 minutes dual, the shortest taking 4 hours 55 minutes. Far from presenting difficulty, the dual instruction required before solo is approximately one-third less than on the piston Provost, and the graduation standard has improved immeasurably. The pupil quality has been very highly commended by teams of examiners from the Central Flying School, R.A.F. and from the Training Examining Squadron of N.A.T.O.

The entire training has been with jet power; the pupils have formed no undesirable piston/propeller habits ; they have had nothing to unlearn, and nothing to break the smooth continuity of their training. Because the need to learn jet conversion halfway through their training has been removed, it has been possible to reduce the hours spent on the more costly advanced stage and, to a lesser extent, the overall flying hours pre-wings, with the result that the cost per pupil trained is actually less than when the piston engined first stage is employed (see Fig,J) , If this is true where the Vampire is used, it is clear that an even greater saving is effected where the more expensive converted operational jet fighters, such as the Lockheed T.33, are in use as Advanced Trainers. The fact that the Jet Provost has been ordered by the Royal Air Force, at the time when economy plays such a large part in our national outlook, speaks for itself, and it also shows their complete confidence that this aircraft will not only be used with the present Advanced
Trainer but will also phase into the more advanced trainers of the future .

The Jet Provost has now proved itself capable of taking the pupil from the very beginning of his pilot training and through at least two-thirds of the pre-wings syllabus. By its use the training types of aircraft can be limited to two only and the cost of spares, special tools and ground equipment, and the technical training of maintenance staffs kept to the absolute minimum. 'A multiplicity of aircraft types in any flying organisation is extremely uneconomical and should only be tolerated where it is completely unavoidable. Naturally there are occasions when an air force is financially unable to discard elementary piston engined trainers while they are still capable of performing a service. In such cases the Jet Provost performs an intermediate role between the elementary and the advanced stages, Its ability to undertake many of the functions, including conversion to jet techniques, as satisfactorily as, and far more cheaply than advanced jet trainers, enables the numbers of the latter type of aircraft to be strictly limited to those required for high-speed , high-altitude training, the only roles for which such aircraft are essential. If, as the existing fleet of elementary trainers diminishes by normal wastage, it is replaced by additional Jet Provosts, the two-stage training scheme will eventually supersede the transitional three stage method.

It is important to appreciate that the Jet Provost is the only jet trainer in existence actually carrying out the ab initio and the intermediate combined roles. Other jet trainers designed as jet conversion, or intermediate trainers, have been tried out experimentally in the ab initio role but ab initio solo has only been achieved at the expense of frustratingly long hours of dual instruction (see Fig. 2). This is not surprising since these aircraft have been designed for performance and for a training function not requiring the docile and safe handling qualities and the low speed circuit characteristics which are so essential in a first-stage trainer. It should be noted that the use of an intermediate jet trainer of this character perpetuates the need for a primary trainer and the consequent wasteful three-stage training scheme.

The very rapid progress made by pupils in the Jet Provost which, hour for hour, puts them so far ahead of piston-trained pupils, is largely due to its excellent climb which has greatly raised the altitude at which practice flying is normally carried out (see Fig. 3). The earlier 5/8,000-ft. practice layer has now moved up to 15/20,000 ft. with a corresponding relief in air space congestion and an increase in safety. Furthermore, the higher altitude is much more in conformity with the conditions to be experienced in the later training and in the operational sphere.

Thus the use of jet power from the beginning has, in one step, removed two training barriers - that of the transition from piston to jet, and that of low level to high altitude flying.

The adoption of the nosewheel tricycle retractable undercarriage removes yet another barrier, since the pupil will continue to handle this arrangement throughout his career. Also it enables practice landings to be of the roller (touch-and-go) variety in the ratio of about four rollers to one stop landing. This greatly speeds-up landing training, reduces congestion on the ground, and wear and tear on brakes and tyres.

Few tasks make greater demands on an aircraft than that of initial pilot training, subjected as it is to handling by the complete novice, and a far higher ratio of landings to hours flown than any other aircraft. The fact that the first Mk. 1I Jet Provost delivered to the Royal Air Force carried out 975 instructional landings in 338 hours with no trouble whatsoever, is an indication of the rugged nature of the structure, and the thought and care given to the need to reduce maintenance to the absolute minimum.

The maintenance problems associated with training aircraft are in a class of their own, and because the Jet Provost is the third consecutive type of ab initio trainer supplied to the Royal Air Force by Hunting Percival, this company is in a unique position to appreciate them. Built into the Jet Provost is the knowledge gained from many hundreds of thousands of hours of training flown by the company's. products in widely varying conditions throughout the world.

Trim, purposeful and workmanlike, The Royal Air Force has used the Jet Provost over the past two years. It has proved outstandingly economical and the graduation standard has been exceptionally high. The neat appearance of the Hunting Percival Jet Provost is very much in its favour, This pair, widely used for demonstration purposes, does not carry the more usual Royal Air Force roundels.

As may be expected the freedom from vibration of the turbojet engine very considerably increases the serviceability of instruments and radio. Also the relatively simple engine demands very much less maintenance than does the piston engine with its associated constant-speed propeller mechanism.

 

Contemporary 50's De Havilland Vampire Advertisement

The prolonged pupil training trials carried out by the Royal Air Force with the Jet Provost/Vampire T.11 sequence, before the decision to adopt this method of training, has removed the question of its practicability from the realms of theory; they have demonstrated in a decisive manner the desirability from every aspect of all-through jet training, given tried and suitable training aircraft.

The cost of modern operational aircraft is such that only the very best available training equipment is good enough. It is in this category that the Jet Provost belongs.