Savouring the Supermarine Spitfire

Flying the Spitfire

Back in the 1940s, a young fighter pilot would probably qualify on the Spitfire within a period of only a few months, having trained during this time on types such as the Tiger Moth and Harvard. Once qualified on type, he would then almost immediately be engaged in major air battles. My own route to the cockpit of a Spitfire was somewhat longer, almost 25 years to be precise from my first aircraft solo. Nevertheless, when the opportunity arose it was immediately obvious to me that the wait had been worth it. The Spitfire is a real pilot’s aeroplane and an absolute delight to fly. These days, it is important to preserve these now relatively rare and valuable aircraft and so flying time is still strictly limited to that required to maintain a sensible level of currency to display the aircraft safely. However, when the chance of a flight does arise, it is always an unforgettable experience.

The Spitfire saw considerable development during its Service life, later marks being far more powerful and heavier than the earlier versions. As larger power plants were installed, the Merlin engine being replaced by the mighty Griffon, it has been said that some of delightful handling characteristics and simplicity of operation of the earlier marks were lost. The Collection aircraft is a relatively early version; a Mark Vc, powered by a 1600hp Merlin 45 engine. This variant was a ground attack version, characterised by the combined armament of canons and guns and an engine capable of producing high levels of power at low level due to a modified or ‘cropped’ supercharger. The aircraft also flew with ‘clipped’ wing tips at Old Warden in recent years. These were used operationally to reduce drag at low level, although the the wing tips were again were returned to the characteristic elliptical shape when the aircraft was recently used during the filming of ‘Pearl Harbour’. For me, the Mark Vc is characterised by her simplicity of systems and superb handling characteristics, making her one of the ultimate pilot’s aeroplanes.

After a brief walk round to check that all is in order, the cockpit is entered from a walkway on the left wing. The cockpit is small but relatively well laid out (cockpit ergonomics had not really been invented in the 1940s!) and once strapped in tightly there is a real feeling of becoming part of the aircraft. The cockpit is almost entirely original although there is the provision of a small electrically powered oil pump to supply oil to the camshafts before the engine is started. If you are close to the aircraft before start-up, you will hear this pump being operated just after the external ground power is plugged in. The pump is a later modification and is required as at Old Warden the engine may stand for a couple of weeks or more between outings during which time oil will drain down from the top of the engine. In WW2 such breaks were rare, and if necessary, the pre oiling would be conducted by the mechanics removing rocker box covers or attaching oil supply tubes to the front of the rocker cover. Obviously this is an impractical way to operate the aircraft nowadays when flown at widely spaced intervals. The Spitfire Vc only has a single radiator positioned under the right wing. On the ground it is also partially obscured by the undercarriage leg and thus it is possible to overheat the engine if it is started too early before takeoff. You will notice therefore that the Spitfire is usually started up and then taxied fairly quickly to the takeoff point. After a few simple checks, including the pre oiling described above, the engine is primed with 4-5 strokes of the fuel priming pump whilst the ground crew turn the engine over by hand. With the control column held hard back to prevent the tail rising as the engine starts, the booster coil and start button are pressed and the Merlin bursts into life with a characteristic crackle and growl. Ground power is then removed and after a few more simple checks we are ready to go.

The aircraft is easy to taxy and is fitted with pneumatically powered differential brakes. However, there are traps for the unwary. With the tail down the view directly ahead over the engine cowling is almost non-existent and you will see the pilot weaving the aircraft and leaning out from the open cockpit canopy to clear the way ahead. It was not unknown for careless pilots to unwittingly taxy Spitfires into obstructions on the ground. It is also important to keep the control column hard back whilst taxiing and limit the amount of power used. If this is not done, a bump combined with braking could cause the tail to rise with the risk of a propeller ground strike. At the holding point, I hold the brakes on hard and increase power slightly to check the magnetos (2 independent ignition systems) and exercise the RPM lever. This controls engine RPM by varying the pitch of the propeller blades using oil pressure. It keeps RPM to acceptable limits and prevents engine overspeed. By exercising the mechanism, I ensure that the oil in the propeller mechanism is fully warmed and that I will not get a propeller overspeed on takeoff. With a cautious eye on the radiator temperature, which at this stage will be rising quite rapidly, I complete the pre takeoff checks and line up for takeoff.

I normally takeoff with the canopy open, which is a safe position in the case of an accident, and as the power is increased the noise of the Merlin only a few feet in front rises to a deafening crescendo. It is important to feed in power relatively slowly, so that speed can increase and rudder effectiveness can become established before the aircraft is subjected to the torque of the engine at full takeoff power. The rotation of the propeller causes Merlin powered Spitfires to swing to the left on takeoff and I initially use fairly harsh rudder inputs to prevent a swing developing. At the start of the takeoff roll, with the tail down, a swing can be hard to detect and so I glance to the side of the runway in the 2 o’clock position to check that we are tracking straight. The swing is caused by the torque reaction of the engine causing the left wheel to dig in slightly, by yaw from the spiral airflow over the fin and by gyroscopic precession as the tail is raised. As speed increases, I can ease the stick forward to raise the tail and for the first time I have a clear view ahead. The Spitfire is very light in pitch, and I take care not to over control and risk a prop strike. The correct attitude is with the horizon just not visible over the propeller spinner and I work hard to hold that attitude whilst keeping straight and checking that I have correctly set the takeoff power setting of 9 psi boost. It soon becomes apparent that the aircraft is ready to fly and I ease her into the air at about 70mph. After takeoff it is necessary to change hands on the stick to raise the undercarriage and again there are a couple of traps for the unwary. The throttle friction must be set extremely tight prior to takeoff, otherwise when the throttle is released to raise the undercarriage, the engine vibration may cause the throttle to close (or the RPM lever to retard) with an embarrassing loss of power at a critical stage of flight. The undercarriage itself is hydraulically powered but operates with a complicated system of chains and cams between the selector lever and the jacks and if it is not moved with the right cadence it is possible to jam the mechanism. This is bad news as a partially retracted undercarriage will blank the radiator and quickly add a rapidly overheating engine to the pilot’s undercarriage problem. With the undercarriage retracted I bring the power setting back a little to the display setting of about 7 boost and the RPM back to about 2600RPM. The rudder trim, which was set fully right to help counteract the takeoff swing, is returned to neutral and after a quick scan of the engine instruments (oil pressure and radiator temperature in particular) I slide the canopy forward and am ready to start the display.

The display is generally flown with a constant power setting although the throttle may just be moved forwards slightly to increase power towards the top of looping manoeuvres. The aircraft is extremely responsive about all axes with a good roll rate and a very light feel in pitch. In pitch there is excellent feedback to the pilot if he is approaching the accelerated stall in the form of a progressive ‘clatter’ felt throughout the airframe. I aim for a smooth display, trying to allow one manoeuvre to flow into the next. The engine does not like negative g and so the display is flown with positive g throughout. Later Spitfire variants, including ours, had modified carburettors to overcome the problems of fuel starvation under negative although we still restrict the aircraft to positive g to maintain oil pressure and to help extend engine life. There is no g meter in the cockpit although I limit the display by feel to about +4g to reduce wear and tear on the airframe. With so much power available, the aircraft requires smooth rudder inputs to remain in balanced flight as speed varies but in practise this is easy to achieve. During the display, the speed will vary between about 100mph and 300mph with 260mph being a sensible minimum for pulling into vertical manoeuvres. The altitude will vary from a minimum of about 50ft to about 2000ft agl. The Spitfire is one of those aircraft where the pilot really gets to feel part of the aircraft he is flying and she is a superb aircraft for low level aerobatics. Although not part of a normal display routine, the stalling characteristics of the aircraft at low power are benign with good stall warning and little tendency for a wing drop, despite the highly tapered wingtips. However, care must be taken with a power on stall, which can cause a rapid rate of roll to develop.

After the display, it is important to throttle back gently to preventing damaging engine backfire and to allow temperatures to stabilise within the engine, which will have been working hard for the previous 5-10 minutes. The undercarriage is lowered at about 140mph as late as possible on the downwind leg of the circuit (to prevent radiator overheating) and I aim to start a curved final approach from abeam the landing threshold at 100mph. This is important as the view from the cockpit becomes poor again as the aircraft is slowed into the landing attitude and it is easier to keep the touchdown point in sight from a curved approach. The pneumatically powered landing flaps are lowered about half way around the finals turn. Once lowered, they block the radiator outlet and so if lowered too early they can cause the engine to start to overheat. I aim to cross the threshold at 75mph and the throttle is closed as the aircraft settles into a (hopefully!) smooth three-point landing. The landing is probably the most difficult aspect of flying the Spitfire, purely due to the extremely poor view over the nose. Once on the ground, the pilot must respond rapidly on the rudders to keep tracking straight, with gentle braking used to assist steering as required. However, once again care must be exercised to prevent a propeller strike if harsh braking is used. The engine is shutdown quickly when on the chocks, as the temperature will again be quite high by now. The aircraft is then once again returned to the engineers and I give feedback on how she has performed. Some times, if radiator temperature is approaching the limit during taxy in, you may see the pilot stop and shut down early.

The Spitfire should be flying for your visit to Old Warden today and hopefully this article will have given you some insight into the operation of such an aircraft. Unsurprisingly, she is one of the most popular aircraft amongst the Collection pilots and we hope you enjoy watching her as much as we enjoy flying her.
Enjoy the display!

Trevor Roche
Oct 2004

Trevor Roche