The collection owns a genuine Bleriot (Channel) Type XI, built in 1909 by Louis Bleriot himself. The aircraft is in wholly original condition, aside from having been re-covered, and having a small main undercarriage modification; and has its original Anzani 3 cylinder motor. The aircraft has been in Shuttleworth hands since 1935 and has been maintained in flying condition since 1936, when it was flown by Richard Shuttleworth himself at the Royal Air Force Display. Since then it has appeared at many air displays both before and after the Second World War.
Because of the low power and the uncertainty that the motor will continue to run for more than a couple of minutes at full power, the flying of the aircraft is limited to hops lasting the length of the airfield only. Let us now look at this fascinating machine in detail, and see what a typical flight consisting of three of these hopsisjike.
The aircraft is a wire-braced monoplane, with single tail and rudder surfaces. The wings are heavily cambered and are supported by king posts above and below the centre section. Through this structure also go the wires which are used to warp the wings for lateral control. The fuselage is an open lattice construction of wood, wire braced; and the pilot sits in a splendidly uncomfortable wickerwork seat just abeam the wing trailing edge. As a concession to decency, the sides and bottom of the fuselage are covered with a loose canvas snap-on cover as far back as the seat, but aft of this, where side covers would help to supplement directional stability, they are absent. There is no fin, and the rudder is extremely small. The tailplane is unusual in that it also has heavy positive camber and that the inboard portion is fixed. The elevators are mounted outboard of this fixed portion and comprise the whole tip each side. They are hinged roughly at mid-chord and have a very large range of movement. The undercarriage is a tailwheel design, with bungee springing, and has the unusual feature that all three wheels castor freely, against a light spring force.
The pilot’s controls are a little peculiar to the modern eye, but they work in a conventional fashion. The control column is pivoted at its base, and moves in the normal sense for lateral and longitudinal control, but to confuse the issue it has a large fat-rimmed wheel mounted flat on top, which has no function other than to act as a handgrip, and does not turn or do anything else interesting. The rudder bar is smooth wood with no foot restraint, and operates over an uncomfortably large range, so that in use the pilot risks sprained ankles, or worse still a loss of control when one foot slips completely off. What passes for the throttle is mounted on the right-hand side of the control column, beneath the wheel, and is, in fact, the ignition advance and retard. This works in the reverse sense from normal in that pulling it aft towards the pilot increases power, and vice-versa. To complicate the issue, it has a ratchet which locks it on and which has to be released before power can be reduced. This successfully governs the motor from a slow tick-over at about 300 rpm to its maximum of about 1,000 rpm; at which, in its present condition, it yields just about enough of its normal 25 bhp to lift the aircraft off the ground and to fly at about 10 feet in ground effect.
The motor is a three cylinder fan formation, with the included angle of the outside pair roughly 120°. Construction is approximate, to say the least, and the angle between each barrel and its neighbour is different, which makes timing something of a problem. Lubrication is by a total loss castor oil system, fed through an adjustable feed cock from a pressurized tank. The tank pressure is pilot-generated by a hand pump, and of course, feed rate tends to vary with pressure; although the aim, if a hand can be spared, is to maintain 2 psi. Each cylinder barrel has a ring of ventilation holes cut about half-way down the stroke, so that the exhaust gases can be vented direct to the air, in addition to a normal exhaust pipe from the head. This feature, intended to supplement the inadequate exhaust valves, is useful in that combustion can be seen, and mixture strength thereby checked, and very nearly lethal in that it guarantees that the pilot operates throughout in a haze of castor oil mist and exhaust fumes. Having extremely uneven firing intervals, the motor has to have an enormously heavy crankshaft cum flywheel, in addition to the propeller, and even with this the vibration level is high. However, the airframe is so flexible that this scarcely matters in the structural sense, but the pilot is aware of it from time to time as his vision blurs perceptibly. An exhaust valve lifter, necessary to stop the motor, an ignition switch and a fuel cock quite out of the pilot’s reach complete the cockpit picture. Note, if you will, that no instruments at all are fitted aside from the tank pressure gauge.
The first problem that faces the Bleriot pilot is how to get in. The one footstep provided is way out of reach, and every time he leans on the aircraft or catches hold of it to try to climb in, it is apt to sidle away on its castoring undercarriage. Getting in is one of the most difficult parts of the flight, and one sometimes wonders if it ought not to be made impossible. A ladder and a helpful engineer are the solution, however, and once in only the discomfort, exposure and the fact that most things are out of reach are disconcerting. The next stage, the ritual of starting, can now begin.
Since the carburettor is always full open, liberal flooding is necessary, together with priming into the inlet ports, before a start can be considered likely. The trembler coil ignition is then connected to its batteries, and the propeller turned over a few blades to suck the mixture in. Meantime, to take his mind off the fuel pouring out of the carburetter, the pilot pressurizes the oil tank and sets the advance and retard about one-third from the most retarded position. The propeller is now set carefully on compression and, on a call of ‘contact’ from the engineer doing the start, the pilot switches on the single ignition switch. The propeller is swung and, if everything has been done correctly, and the old girl feels like it, the motor fires and we are in business. A blast of cold air comes back from the propeller and at once the pilot has to lower his goggles. Shortly after, the first of the second-hand castor oil begins to arrive in the cockpit area, and the feed is adjusted so as not to oil up the plugs. At this stage the ignition is advanced so as to increase power and make sure that all the cylinders fire and get warm. For some reason, there is a lazy pot on this Anzani — the starboard one — and if it is run for any length of time from cold on two, the third will never cut in. We then have to stop the motor and change the plug for a hot one and try again. It is better to avoid this rigmarole if possible as there is no guarantee it will fire at all the second time, and the engineers do not like it. Once satisfactorily warmed, however, a brief run-up is done to check by ear that all is well, and again to adjust the oil feed; then power is reduced, the chocks waved away, and we are ready to taxi.
The Bleriot is never flown in winds in excess of five knots for reasons of low control power, and for the same reasons we also only taxi in light winds or flat calm. Even so, directional control is so poor that wing handlers are required to do more than taxi in a straight line, or to negotiate any sloping ground. The sloping ground problem arises from the fact that all wheels castor freely, against the weak spring centring system, and so the system generates virtually no side force. Put the aircraft sideways on a slope and it will set off sideways downward at once, unless the pilot can turn it to head up the gradient, and with poor directional control this is often not possible. With understanding handling, the main taxying problem becomes keeping the motor running hard enough to prevent plug-oiling without achieving too high a speed, and not prolonging the process so much that the motor overheats.
Because of the poor directional control, no attempt is made to take off crosswind, irrespective of runway direction. With the aircraft lined up exactly into wind, therefore, one of the handlers holds on to the tail and the motor is run-up to full power, and the oil pressure and feed-rate checked. When all is to his satisfaction, the pilot raises one arm, holds it out parallel with the ground, then drops it smartly to his side. Upon this signal the handler releases the tail, the aircraft rolls gently forward, and the flight is about to begin.
In the few seconds before the aircraft reaches flying speed, the pilot has an opportunity to check the oil feed and by the clouds of oil rushing past him decide perhaps to vary the rate or not. The decision is a hard one, because time is short and the oil cock very nearly out of reach. Assuming all is well, however, and the pilot can still see through his goggles, the tail is raised as a fast walking pace is achieved, and at a slightly nose up flying attitude the gentle acceleration continues until the aircraft lifts itself off the ground. No airspeed indicator is fitted, but 25 mph is probably a fair estimate of flying speed for this aircraft. Even at this modest pace the airfield looks extremely small, and once a wheel height of ten feet or more is achieved, smaller still. The first priority is therefore when and how one is going to get it down again, and unless the pilot is careful the first flight is apt to be over before he has had time even to consider the question of how the aircraft handles. The most striking impression of the aircraft is the large elevator hinge moment, in the nose up sense, which requires a constant 10 lb push force on the stick to hold level flight. A moment’s inattention and the aircraft will abruptly pitch up, and be a great deal higher and be flying a great deal more slowly than the pilot would wish. Luckily, the elevator control is relatively powerful and precise. This high and slow situation cannot be maintained, however, as the motor gives insufficient power to fly out of ground effect and provided prompt action is taken to prevent a possible stall, no harm is done and the aircraft sinks sedately back down to a wheel height of about twenty feet. By this time most of the airfield will undoubtedly have been used up, and it will be time to land, and to begin the long taxi back to the start point for the next hop. As we have never stalled the aircraft, either deliberately, because we cannot achieve a safe height to do so and because the aircraft is virtually priceless, nor accidentally, nothing is known about its behaviour in this regime.
During the next take-off the pilot notices that the elevator push force develops very early in the roll and that once the tail is lifted, a slight relaxing of this forward pressure will allow the wheels to leave the ground a little earlier than if the aircraft is left to itself, and so save precious distance for the flight. There is a limit to the gain to be had from this technique, however, and should the incidence increase too much, acceleration is slowed and the distance once again increases. The best conditions seem to occur at a point just about when the tailwheel would begin to touch. Once airborne again, the heavy vibration is noticed, and a glance at the blurred structure shows just how out of balance the motor is. It is time now, however, to explore the control power, before we run out of airfield, and to see where the limits of controllability might be expected to lie. A small lateral input each way shows that roll power is low, and one rapidly progresses to full deflection, and this yields a delayed and very low roll rate which is also very difficult to stop. At this stage it is apparent that any gust-induced roll disturbance is going to be very difficult to handle, and that some help will clearly be necessary. Therefore, rudder inputs are tried, so as to generate sideslip, and to see if this induces a roll rate. The rudder itself is also found to be weak, even with full slipstream over it, and although sideslip does eventually result, the secondary roll rate developed by it is also very low. It is now clear that the major problem axis of the aircraft is the roll, with directional following it a close second, and we redouble our determination not to fly other than in calm conditions. Once again, however, the end of the airfield approaches and it is time to land.
During the taxi back to the other end of the airfield, it is apparent that a slight wind has got up, and directional control of the aircraft becomes awkward, giving the handler a hard time keeping the direction constant. Also, the motor is showing signs of overheating, so the oil rate is increased slightly and tank pressure restored to 2 psi. Fuel is still not a problem, as we started out with five gallons, which should last for a couple of hours or more, and the sight glass in the tank confirms this. Now also the continuous exhaust fumes are starting to have an effect, and the pilot is covered with a thin film of castor oil. Before the next hop, the goggles must definitely be cleaned, and it is also decided that this will be the last hop in this series, and that on this mainly the landing will be explored.
In the air again, it is soon obvious that the power from the motor is decreasing and that the first landing is coming up fairly soon, like it or not; and that there may not be power available for a second. Nevertheless, rather than let the aircraft sink on itself, power is reduced, and it is surprising how quickly one has got used to the reversed sense of the power lever. At once the nose pitches up again as the slipstream reduces, and with a smart forward stick input the descent is started. The touch-down follows seconds later, and it is a relief to be able to release the forward pressure on the control column for a second. The geometry of the machine is such that without even trying, a three-point landing results, and there is therefore no need to lower the tail. The disadvantage is that as soon as power is reduced in these circumstances, directional stability also is reduced sharply and controlling the roll-out becomes a full-time task. The castoring undercarriage, so soft and gentle in touch-down, now becomes an additional hindrance because even if the aircraft heading can be changed, the lack of sideforce on the mainwheels means that probably the machine will simply crab and maintain its original direction. Opposite wing warp sometimes helps, but in the extreme the pilot has to take refuge in the low speed and just to hope that the thing will stop before he hits anything. In the interests of flight safety we have limited the castoring ability to a fraction of its original value by a wire tie, but the problem still exists.
Power is at once applied again, however, to attempt another hop and landing, and proves to be still sufficient to lift the aircraft a foot or two off the ground. Since distance is very limited, an immediate and final landing is called for, and so for an experiment this time power is abruptly reduced to the idle setting of about one-third advance. The result is an instantaneous speed loss and a much more crisp pitch-up than before. Before there is time to counteract this, the aircraft has landed again, untidily, a little tail-wheel first. Also, a fairly abrupt swing has developed which needs full rudder and a little burst of power to correct, but all is well, and the gentle roll-out is completed some 100 yards short of the boundary, where the handlers turn the aircraft round for the journey back to the flight line. Plainly, the gentle reduction technique is, as expected, the best, and this is obviously the one to be used in the future.
The feeling of well-being and worthwhileness which is always present after a successful flight is never more obvious than now. Not only have we flown, but we have had the unique pnvilege of flying a genuine Bleriot monoplane, in very nearly the exact configuration and circumstances that Louis Bleriot himself might have done. With all its peculiarities and shortcomings, this has been as it always is, a wonderful experience. It is true that wing warping will never replace the aileron, and that one has been smothered in oil, and breathed exhaust fumes for half the time, but this has not detracted one bit from the delight. One can only be grateful for the experience, and wonder at the courage and resource of a man who could design and build such a machine, and eventually attempt and conquer the Channel in it.
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