Flying Shuttleworth aircraft is challenging and different. In order to illustrate some of the differing flying techniques necessary to pilot the Collection’s aircraft, lets look at the history and specific handling qualities of three of the Collection’s classics: the Bristol Boxkite, the SE5A and the Hawker Hind.
The Collection’s Bristol Boxkite was constructed as a reproduction machine by F G Miles limited for the film, ‘Those Magnificent Men in Their Flying Machines’. The Bristol Aeroplane Company acquired the machine after filming was finished and passed it to the Collection for safe-keeping. It has remained there to this day.
Only minor modifications to the 1910 specification have been carried out; minor that is, if you consider the substitution of the Gnome rotary by a modern Rolls-Royce 0200 Continental engine a minor mod. Further, a third rudder has been added in an attempt to improve directional control and a small instrument panel has been fixed to an arm extending from the left of the pilots seat area.
From a flying control point of view, the aircraft is conventional in that it is equipped with elevators, rudders and ailerons. However, the ailerons are fitted with cables that pull them down only, so they droop at 90 degrees to the wing when at rest and take up a streamlined position as the aircraft moves. Adverse yaw is significant *. Couple this with an aircraft that is unstable in yaw and pitch and neutrally stable in roll and she can become quite a handful in anything but calm conditions.
(* Adverse yaw is a phenomena caused by the greater drag of the down going aileron when compared to that of its up going opposite number. There is no up going aileron on the Boxkite, so as right aileron only, say, is applied, the desired right roll is accompanied by significant left yaw. On modern machines, the effect is minimised or cancelled by aerodynamic fixes such as differing aileron movement, or by shaping the aileron so that it produces more drag when deflected up than when deflected down.)
Following a normal walk around where the single skin flying surfaces are checked for condition and damage and the pilot has taken great care not to garrotte himself on the plethora of bracing wires, he now has to find a way into the cathedral, or cockpit area. A leg up, or use of a ladder is essential, but the major problem is negotiating the overlong control column that falls under gravity to the rearward position – groundcrew help is often solicited to hold the offending article clear.
Once seated the rest of the procedure is straightforward, but it is imperative that all pockets are secure as no loose articles must be allowed to fall back into the propeller. It’s also a good idea to tuck the bottom of ones flying suit into ones socks to allow the greatest unobstructed area for air to flow to the engine air intake under the pilot’s seat. The engine works hard with little airspeed to provide cooling and any reduction in airflow could be significant. In fact, the mixture had to be set over rich to increase cylinder head cooling and provide sufficient flight time for filming. More recently, an electronic cylinder head temperature gauge has been fitted to allow the pilot to monitor the engine temperature in flight.
The fuel is turned on by turning a tap in the fuel line under the pilots seat, and priming is achieved by using the throttle acceleration jet. After a few turns to suck in, the switches are set to ON, the throttle is set about 0.5 inches open and the propeller is swung. More often than not, the start is immediate and a four minute warm up generates the necessary 105 degrees centigrade cylinder head temperature required prior to run up. A short taxy follows; the aircraft is quite stable on the ground and can even be steered with the use of ruder and power. Ground-crew help is only required for harsh turns and they can often be seen cadging a ride on the front skids of the chassis assembly, (early speak for undercarriage).
When lined up a final confirmation is made of engine temperatures and flight controls. The elevators and ruder are conventional, but the ailerons cannot be rechecked as groundcrew aid is required to hold them in the flight position to take up the slack in the cables. The latter are attached to the top of the over long control column and with the machine at rest, they droop over the pilots arms as they lead along the leading edge of the wing.
The carburettor heat is set cold and the throttle advanced. Initial acceleration is brisk and within a few yards, life arrives in the aileron cables and the control column gains feel. The aircraft is flown off the ground at about 35 mph and from the pilot’s point of view, this is where the work starts. Owing to the low power weight ratio and the high parasitic drag, the aircraft must be flown in balance for it to perform. Yaw instability with the adverse yaw associated with aileron movement provides an interesting exercise in piloting. A length of string has been tied to the foreplane control horn to give an indication of yaw as it takes up a position streamlining with the airflow. Pitch instability doesn’t help, but it must be tamed as it is essential to keep the speed around 35 mph for the machine to climb. So with eyes glued to the horizon, yaw string and the air speed indicator at the same time, the pilot works hard with the flight controls in an attempt maintain the necessary parameters. At about 100 feet above ground a gentle turn is commenced to fly back past the crowd. Balance is imperative as too much yaw will increase drag to such an extent that level flight may not be maintained. However, when stabilised in level flight, engine power may be reduced for the cruise to give the hard worked Continental a breather before the next turn is demanded.
Having now learned to fly the machine the pilot may now notice the incredible cockpit field of view afforded by sitting on the front of the wing. This is no place for agoraphobics. He may also try the limited flight envelope of the aircraft. It has been test flown down to 25 mph and up to 50 mph; normal flight operations are therefore, contained within 30 to 45 mph to give a safety margin. The glide with the engine off can only be described as steep and mental note is made that in the event of engine failure, the only landing ground available is practically underneath the machine – I knew the exceptional field of view would come in handy.
Now the landing approaches. It is only necessary to throttle back slightly and maintain 35 mph to achieve a rate of descent. A colleague once described the technique for bringing the Box back to earth as: "…one doesn’t land the machine in the normal sense, one just runs it aground". It’s exactly as he described, as ground effect is reached the aircraft rate of descent slows and if 35 mph is maintained the machine will just, …well, just…run aground!
The Collection’s SE5A was discovered hanging in the roof of the Armstrong Whitworth Flight Shed at Whitley, Coventry in 1955. It was restored for the Collection by staff and apprentices of the Royal Aircraft Establishment at Farnborough and flew again in 1959. Following problems with the original Hispano-Suisa engine, it was replaced in 1975 with a Wolseley Viper. Farnborough handed over their interests in the machine on 21 October 1992 and it remains at Old Warden as the World’s only genuine flying SE5A.
First impressions of the machine are that it is small, compact and it can pack a punch with its two 0.303 inch machine guns. It has a large motor and it’s heavy, especially when trying to push it out of the hangar. On climbing in one must avoid the overhead Lewis gun otherwise a scarred forehead will result. On sitting down, the compactness of the cockpit becomes immediately apparent. I’m not particularly broad in the shoulder, but the cockpit width is forced to expand slightly as my shoulders touch the coaming. Pilots during World War 1 often cut back the coaming on their personal aircraft to provide adequate room and to customise it for their own particular needs.
Before start it is necessary to pump the fuel tanks to pressure with the hand pump on the port side of the cockpit. That done, the engine is primed by cockpit hand pump, the throttle is set, the fuel and air turned on and all is now ready for the start procedure.
A starter magneto with an external handle provides a shower of sparks for the start; one ground crew swings the propeller, another vigorously turns the starter magneto and possibly a third guards the tail to prevent a nose over. As the engine bursts into life, the starter magneto is switched off and the engine revs are monitored to prevent an oil overpressure.
The heavy weight of the aircraft provides good wheel drag, which combined with a steerable tail skid and high engine power makes taxy an enjoyable experience. Engine overheating is solved by pilot controlled slats on the front mounted cooling radiator, all the pilot has to do is monitor coolant temperature and maintain it between 65 and 90 degrees centigrade by use of the slats.
Take off is a revelation. The power weight ratio is high, possibly the highest of the Shuttleworth machines, and acceleration is brisk. The aircraft breaks ground quickly and cleanly and the climb speed of 65 mph gives a high nose attitude. Control response is good in all directions, especially roll with the four ailerons. However, adverse yaw is still very much apparent. A deflection of the ailerons only produces a side slip in the opposite direction to the desired roll of such a magnitude that a perfect steady heading side slip results. No matter, the rudder is light and powerful, and great pilot satisfaction can be had striving for the correct co-ordination of flying control input to achieve perfect balanced flight.
It can now be clearly seen why the aircraft was so much loved by the pilots who flew her to war in 1918. The engine power, the control response, the gunsight in the forward view from the cockpit, the Vickers gun that protrudes from the front fuselage coaming, all combine to give the impression that this machine really does mean business.
She’s a fighter so she’s aerobatic. Again, what a delight she is to fly. Loops and rolls are performed with ease. She may be a little loose directionally, but it’s difficult to find fault in a machine that was so far ahead of its competitors in its day. Stalls are also quite benign. The stall break occurs at about 45 mph with a wings level mush. 1990 handling qualities in an 80 year-old aircraft.
A landing must follow every take off. The aircraft glides and sideslips well and the approach may be made engine on or off as required. The radiator slats are closed to prevent engine cooling and the tailplane trim is set fully back to allow full elevator movement for the round out – longitudinal trim is achieved by adjusting the incidence of an all flying tailplane by use of a wheel located on the port wall of the cockpit.
Now we must appreciate the only two handling criticisms on the machine. At round out, just before the stall, a wing may drop in ground effect. A go around must not be attempted for if the wing had touched, the aileron horn may have been damaged and roll control of the machine will have been lost or at best severely degraded. Also at touch, the fuselage inertia coupled with the sprung tail skid sometimes leads to a switch back ‘bucketing’ motion that is most uncomfortable in the cockpit. The only action the pilot can take is to ride it out with the control column held hard back. A go around attempt will only lead to a broken propeller and a shock-loaded engine. That said, most landings in the aircraft are as benign as the in-flight stall. One leaves the machine with the impression that she was way ahead of her time; a great example of British engineering at the beginning of the last century.
The Hawker Hind takes us to 1934. The Collection’s example was delivered new to the Royal Afghan Air Force (RoAAF) in 1938 where she remained until the 1970’s. The machine was kindly donated to the Collection and after an overland journey of some 6000 miles with SVAS volunteers and followed by restoration at the Collection she flew again on 17 August 1981. She was initially coloured in the markings of the RoAAF but she was later repainted and now regales in the markings of XV Squadron Royal Air Force. As with the SE5A and several other Shuttleworth aircraft, she remains the only airworthy example of her type in the world.
Walking towards the Hind one can only be impressed with the lines of the machine. What a wonderful sight she is, dressed all in silver with virtually not a straight line in view. If they look right, they fly right, and the Hind is no exception.
The route to the cockpit is interesting. Various hand-holds and foot rests are available and a little thought is required before committing oneself to the climb. There is nothing more embarrassing than ending half way up the side of a cockpit with crossed legs and nowhere to go when in full sight of several hundred spectators. It’s also important not to use the cockpit coaming as a hand-hold. It’s a light wooden fairing put in place only to smooth the airflow and fair in the pilot. In no way can it support the pilot’s weight.
When seated, the general impression is one of size. The machine is vast and so is the cockpit. The instruments and controls have been thrown in place with normal British ingenuity, but after a few moments contemplation, a certain logic does present itself and most controls and instruments come easily to hand.
Starting is normally carried out by Hucks starter, which is an external turning source based on the chassis of a Model T Ford. Priming is by cockpit hand pump and fuel pressure is produced by two gravity-fed tanks in the upper wing centre section and an engine-driven pump from the main fuselage tank. The Kestral crackles into life, the airframe vibrates, the machine has now come alive.
Warm up of the liquid cooled engine takes about seven minutes, after which the coolant temperature is pilot controlled to the same limits as the SE by manually winding the under-fuselage cooling radiator in or out of its housing. Some specific low rpm’s produce an airframe resonance and must be avoided; otherwise, the only significant starting characteristic is the warm up time.
Apart from the shear size of the aircraft, taxy provides no particular problems. The machine is equipped with compressed-air brakes operated by a handle on the control column, so ground steering is becoming easier.
Following line up on the runway, there are a few more items to check than in earlier types as the machines have now become more sophisticated. Trims, temperatures and pressures, fuel cocks and pilot’s harness are checked in turn, then its time to move. The throttle is opened slowly and smoothly to about zero boost – the Kestral is supercharged, higher boost is available, but not required. The acceleration is smooth and progressive, the controls quickly gain life and feel. There is little swing as the tail is raised, but one cannot fail to notice the random movements of the cockpit coaming fairing. Had it not been checked on strap in, it would give the definite impression that it was not attached to the airframe.
The machine flies naturally off the ground at about 50 mph and settles in a climb. Inertia around all three axes is high and the controls are not as effective as the SE5A, but the feel is good. Its a heavy aeroplane, a bomber, but the controls are well harmonised. Adverse yaw is minimal and the general impression is a great improvement on earlier types. Stalling and manoeuvring pose no particular problem, but the weight of the machine can be felt at all times. The aircraft is capable of and stressed for aerobatics, but they are not currently approved by the Permit to Fly. We must content ourselves with steep turns and wingovers, but one day…!
In flight the cockpit can only be described as warm and windy. Air from the radiator is guided into the cockpit for heating at altitude. A flap gives some control over the flow of air, but at low level in an English summer, it is either too hot or much too hot. Also, at the cruise speed of around 145 mph, the cockpit draught is at a similar speed and loose flaps of clothing or a poorly folded map cannot be tolerated
Before landing the speed must be reduced from the cruise of around 150 mph to the approach value of around 65 mph. This is easier said than done as the machine has little drag. The trim is set fully back and power reduced. Around finals, the engine is strangely unstable, it hunts, pops and farts, but it hasn’t stopped yet, neither will it, it’s just another characteristic of a 1930’s vintage fuel system that doesn’t like low power settings at low speed.
The aircraft can be landed smoothly in the three point attitude, the controls are powerful and progressive. Any swing on deceleration must be stopped instantly to prevent ground looping, but the brakes are good and the rudder powerful.
Well, that’s it. A brief sortie in three of the Collection’s classics. Each was designed for a different job in a different aviation era. Their comparative performance and handling qualities are as different as chalk is to cheese, but safe flight demonstration is possible owing to the engineering and piloting skills currently retained within the Shuttleworth Collection. This should not suggest that flight in a Shuttleworth machine is difficult, better to that it is different. Challenging, yes, difficult, no.
If you wish to see the aircraft, visit the Collection on any day except the two weeks over Christmas. If you wish to see them in flight, visit on a display day. Details can be obtained on the Collections web sight [www.shuttleworth.org], by telephone on 09068 323310 (60p per minute), or send an SAE for a program to The Shuttleworth Collection, Old Warden Park, Biggleswade, SG18 9EP. Alternatively, you can help the Collection directly by joining the SVAS (Shuttleworth Veteran Aeroplane Society), contact: SVAS, PO Box 42, Old Warden Aerodrome, Biggleswade, SG18 9UZ.
© A J Sephton