Chilton Aircraft


  Pre-war articles on the Chilton Monoplane
Something Big in a Small Way - 1938 High Performance in Minature - 1937

More Power For The Chilton - 1939
Really Practical - 1938

Sporting Flying - 1939
Chilton Flying Instructions - 1937

Carden Aero Engines - 1935
Train Aero Engines - 1936

Popular Flying - 1938

Something Big in a Small Way

The Aeroplane - January 19th 1938

On one of Decembers few decent flying days the Hon A.W.H. Dalrymple flew the Chilton monoplane over from Hungerford to Hatfield, and I had a few enjoyable minutes in the best ultra-light aeroplane I have yet flown. Photographs of it appeared in The Aeroplane of December 8th 1937.

A sweeping statement like that calls for definition of the standard of comparison. In short, it appealed to me as having better performance in general, combined with real flyability and short-landing characteristics, than anything else in its power class and the soundness and finish were unusually good.
When I say they started with a considerable handicap in the Carden motor I refer to its weight and that alone. What with radiator, plumbing, water and oil the power plant accounts for a good 180 lbs. In working order, and at 32 h.p. the power to weight ratio has a rather grim figure of 5.62 lbs. per h.p. This is a nasty jolt to the designer, who probably thinks wistfully about steam, and also calls for greater strength and weight in the airframe.
The latter consideration is less than might be thought, as Mr. Dalrymple pointed out, a wing spar can be made twice as strong for a very few extra pounds of wood. The Chilton wing has withstood sand tests up to a factor of 12 or thereabouts before collapsing, Nevertheless the power loading works out at nearly 25 lbs. per h.p. in spite of all the trouble taken to keep the airframe light, and as the wing loading is about 9 lbs. per sq. ft. the performance of the finished machine is a real achievement.

The Chilton is called by its builders “a real aeroplane in miniature” and this is a fair claim. Among the characteristics of a real aeroplane is a dislike of small spaces which is almost prohibitive and the Chilton runs true to type in needing a real aerodrome for take-off. It will land very short, which is the main thing, but in its class we long for a “paddock performance”.
It looks like an aeroplane, the design is really clean and well finished, without external control wires. Is striking resemblance to a well known type is conveyed by a remark of an onlooker at Hatfield as it taxied up: “Blimey, the ‘Awks had pups!” Inside the attractive finish is still apparent. The instrument board is very car-like, and the throttle is worked French fashion, pull to open, push to shut - by the familiar push-pull knob as on the dash of an 8 h.p. Ford. The oil and water thermometers are combined in a neat single instrument particularly easy to read.
A normal stick and rudder pedals of the sailplane type are used. Entry is slightly awkward, which will not matter in the least to the pilot of this sort of single seater, but the seat is comfortable and when both flap doors are closed there is a notable absence of draught.

The Carden motor has dual magneto ignition, and started at once to idle with the smooth quietude so noticeable in these little motors. I have flown behind them in three other ultra-light types and always felt happy about them. One may say that a power to weight ratio of more than 5 lbs. per h.p. ought to mean reliability at least, and in a motor which must be cheap as well it probably does.
The Chilton has no brakes or steerable skid, but can give points in ground manoeuvrability to many which have. As Mr. Dalrymple taxied in I was sure he had brakes because his steering was so positive among the puddles.

At the take-off I found the tail came up quite well but I made rather a long business of it. One does not like to lift new types off in a stalled condition until one knows what the taper does to the ailerons. I should think it was nearly 200 yds. before it lifted cleanly at 45 m.p.h. The best climb is about 60 m.p.h., but as it was bumpy I held 70 m.p.h. at first. I was perfectly astonished at the height to which one had to pull the nose to bring the air speed down to so m.p.h. With 30 h.p., and heavy at that, one expects to nurse both speed and height with great care, but the Chilton seemed not to mind, and took me to 2,000 ft. in five minutes.
For climbing there is no substitute for surplus power. The process is a matter of sheer foot pounds over and above the urge needed merely to fly and maintain height. The latter is helped enormously by clean design, and the fact there was enough h.p. surplus from a very moderate allowance of 30 to lift some 600 lbs. 2,000ft. in that time is greatly to the credit of Messrs. Dalrymple and A.R. Ward the joint designers.
Immediately on letting the nose down the speed picked up and quickly reached 100 m.p.h. I eased the knob into the dash until the motor settled down to the cruising r.p.m. of 3,100, the maximum is 3,400. The air speed reading was just under 100 m.p.h., but I could get this speed by using another 100 r.p.m. The motor was quite decidedly one of the smoothest I have ever sat behind, and although its stub exhausts sound rather dreadful from the ground I really noticed nothing unpleasant from the cockpit. The absence of vibration means a lot.

Both water and oil were at very reasonable temperatures after the climb, so I did a flat out stretch at an airspeed reading of 110 m.p.h. The controls are brisk, personally I should say they were just too much so for a beginners. They remind me rather of the Comper Swift except that the elevators are just as snappy ailerons and rudder. This is the sort of aeroplane one would get very fond of indeed but it is not entirely restful for map reading, etc.
There is no hunting or instability when the feet are taken off the rudder pedals, and perfect turns can be made on the stick alone, an excellent performance for a shortish machine, and proves a good air flow over the fuselage.
The stall without flaps comes at a reading of 44 m.p.h., from an average of three attempts, and always follows a drop of the right wing. Recovery is instantaneous, and I am told that this is true of spinning either way. I did not try.

The flaps which open easily by means of a hand lever on the right have four positions to choose from. When fully open they postpone the stall to below 40 m.p.h. and make quite a steep glide out of what is ordinarily a very flat approach indeed. The landing is easy enough, but the sensitivity of the elevators inclines one to pump handle if clumsy from flying machines with slower reactions.
Mr. Dalrymple was puzzled at my suggestion that responses were too brisk for beginners. He explained he had flown it first when he had only forty hours solo and had noticed nothing very difficult. He intended it for beginners rather than old hands. Perhaps he is right. After a fairly mixed experience one is very apt to judge wrongly just what the beginner will find easy and what will disconcert him. An aeroplane like the Chilton, which seems to have no vices but needs flying, keeps the mind on the job, and that may be as good a safety device as a spurious fool-proofness. The Chilton costs £315, and I still cannot imagine how they do it on the power.

F.D. Bradbrook

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High Performance in Miniature

Some Comments on the Chilton Monoplane - Cruising at 100 m.p.h. on 30 b.h.p.

Flight December 30th 1937

After little more than half an hour’s flying in a new type it may seem somewhat presumptuous to make any comments on its handling and general qualities. One the other hand, initial impressions are those which really matter, since, after several hours experience, one becomes so a accustomed to a particular machine that it is difficult to remember and to analyses flying impressions as such. However, it was necessary to be content with a little plain circuit flying - which, at least in visibility of two thousand yards order, leaves one’s mind free to consider a flying machine simply as a machine and not as a navigational implement.
Probably the first reaction of any person on being told of a machine which actually cruises at something rather better than 100 m.p.h. on less than 30 h.p. is that such a performance must somehow be paid for, either in a high landing speed, or in some vicious characteristic. In fact, the Chilton is perfectly normal in all its habits and it lands, with the assistance of split flaps, at a good deal less than 40 m.p.h.

It's flying characteristics might be likened to those of any high efficiency low wing monoplane, built to a small scale. Furthermore, the machine has a good rate of climb which is sufficiently good to remove any of those tree-scrapping illusions from which one suffers in many ultra-lights, the makers figure of 650 ft/min. is certainly not an optimistic invention. Provided that one has a properly instinctive realisation of the moment when a machine is ready to fly, the take-off, too, is quite short in distance, though moderately protracted in time. In fact, and according, as might be expected, to the purposes for which an owner requires such a machine, he can always by a change of airscrew, obtain a superior take-off and climb at the expense of cruising speed.

The machine which I flew was fitted with a compromise in airscrews, and although it is never possible to guarantee indicated speeds, the machine reached its 100 m.p.h. quite quickly after leveling off, and comfortably held 95 m.p.h. on very little more than 3,000 r.p.m. - 300 r.p.m. less than normal cruising. The best climbing speed appeared to be 60 m.p.h. The Ford engine is a comfortingly smooth means of propulsion, and at no time did the water temperature gauge reading exceed 85 deg. C.

In the matter of controls the Chilton is light and positive, and the machine, so to speak, demands that every turn should be a steep one. A couple of near vertical rounds was my closest approach to aerobatics, if some flat side-slipping is discounted. This last manoeuvre the machine does well and properly, though the speed cannot be kept below about 65 m.p.h. With three position split flaps, however, the need for such height losing tactics is not really obvious and the best way of approaching without a motor would be to play tunes on the flap lever between the first two notches, and to apply it fully just as the boundary has been crossed at 60 m.p.h. or so. With the flaps right down the gliding angle is steep enough to suit anyone - and with flaps up it should be possible to cover a couple of counties downwind from 2,000 ft. Until the true air-brake, independent of lift flaps appears, all split flap controls should obviously have a series of positions for different circumstances.

Whether or not I was being too cautious with an elevator control which I knew to be very sensitive at low speeds, or whether the view of the ground as the tail goes down is an awkward one until the pilot becomes accustomed to it, the fact must be admitted that my first landing was a thoroughly bad one. I was a wheeler for a start, a slight ridge or a gust sent me flying again, and the results were made even worse by the accidental use of the engine at the wrong moment. The useful width of the undercarriage and its four inches of travel saved the day (i.e. one of the wing tips) and this minor experience proved that the Chilton would take at least something of a hammering that might be provided by a thoroughly raw novice. The next two landings were irreproachable, so I am ready to take all the blame.

The accidental throttle motion was indirectly caused by a control system which works in the opposite direction to normal. This is a purely personal arrangement with this particular machine, and at no other moment did I object to the fact that the dashboard control must be pulled rather than pushed - the idea being to have the plunger out of the way when closed. The use of glider type or harmonium rudder pedals is quite another accidental feature which, consequently, may hardly be criticised, though paddling is thereby encouraged, full leg rudder bar movement certainly provides one with more definite control. Any other machine (a second one is coming along now) may have a standard throttle movement and a normal rudder bar at the discretion of the purchaser. The next machine, too, will have the flap lever on the left side of the cockpit, where it may be moved without changing the stick hand.

It is obviously impossible to deal adequately with the characteristics of an aeroplane in a few hundred words. Let the Chilton be temporarily explained as the useful result of a real endeavour to produce an economical, and properly finished machine with normal characteristics, yet an outstanding performance.

“Indicator”

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Really Practical

Out and About in the Chilton Light-weight : Cruising at 100 m.p.h. on 30 hp :
Safe Characteristics

Flight July 7th 1938

Late last year I spent a short period in the air with the prototype Chilton monoplane and felt at the time that here was a machine which, though economical in first and later costs, was yet entirely fit for serious use. Unfortunately, the particular day was by no means ideal for trying out any new machine - let alone one about which, in view of its quite exceptional performance, I felt a certain, perhaps, justifiable timidity. There are ultra-light weights and ultra-light weights. A low cloud ceiling effectively prevented any attempt to discover exactly what happened to the machine near the stall and, as the Chilton is intended for the novice and the expert, its slow speed characteristics seemed after all, to be the very ones which would make or mar it as a flying machine.

However a week or two ago, I had an opportunity to renew my acquaintance and flew the machine for about three hours in good weather conditions. This, too, was the first of the production models, in which one or two minor improvements had been incorporated. Gradually during the three hours, I gained more confidence, not only in the machine, but in the power unit which as a converted car engine, might otherwise cause the prospective owner some slight misgivings. The Chilton-Ford engine continued to perform with monotonous smoothness and regularity, and furthermore, I found on a trip down to the south coast and back again along the line between Lympne and Tonbridge, that the Chilton’s cruising speed really is 100 m.p.h., as nearly as makes no matter.

In the course of this cross-country flying the machine was not by any means kept on a steady course or at constant altitude, yet the inclusive average over the out and home run was in the region of 88 m.p.h. On the only soberly flown section of the route I timed the machine over a distance of ten miles, the wind was almost across my track and the distance was covered in a little over six minutes - a time which gives a speed figure of about 95 m.p.h. This was at an engine speed of 3,400 r.p.m., which, with the particular airscrew in use seemed to feel about right.
Actually, the unit, at least according to the Ford people, is perfectly safe up to about 7,000 r.p.m., not only, therefore there is little danger of over revving on a dive, but this high limit also permits variations in cruising engine speed to suit the slight differences in airscrew design which so often appear in the small sizes. At 3,400 r.p.m. the throttle was approximately half open, though without a manifold pressure gauge it is not possible to calculate the amount of power which is being taken out of the engine.

For those who still consider that this engine speed is somewhat high for reliability, it is worth remembering that it is merely equivalent to the normal top gear cruising speed of the Ford Ten car. Since the modified Chilton engine has a special cylinder head and a special forged crankshaft, with of course an airscrew thrust race, there is every reason to suppose that the unit should be adequately reliable and hard wearing judged by aircraft standards.
Practical tests with the engine have in fact included 100 hrs. at 4,000 r.p.m. (full throttle), and examples fitted to Drones have done up to 250 hours without requiring anything more than routine adjustment. Naturally enough, it is possible for the radiator water to reach an unnervingly, but nevertheless perfectly safe high temperature if the engine is badly over driven. The Chilton has a temperature gauge on the dashboard, and in normal cruising flight in mid-summer the temperature did not exceed 95 deg. C. which is just about right for efficiency.

I have concentrated rather on the engine side of the business because this, I feel, is one which may be doubted first of all by the prospective owner, however much he may like the Chilton as a flying machine pure and simple. Except for what is perhaps an over light rudder, it is impossible to make any complaints about the adequacy of the Chilton’s controls at any speed from 40 to 140 m.p.h.
At the stall, with flaps up, the machine tends to drop its nose a trifle while one wing falls away very gently, and in these circumstances the rudder becomes the master control, the merest touch keeping the machine level at an indicated speed of less than 40 m.p.h. With the flaps down the actual stalling speed is lower and the machine appears to remain quite stable and under full control with the stick held right back. The Chilton flies and turns perfectly on ailerons alone.

The wing section is a modified Clark YH, and is such that the machine has really thick wing characteristics. It must be hauled off the ground, but even at very low speeds there is absolutely no tendency for a wing to drop suddenly. There was very little wind when I flew the machine out of Gatwick, but the take-off run was measured at approximately 80 to 90 yards over a particularly hard and consequently bumpy surface.
The ground angle of the Chilton is somewhat sharp and full rearward stick can be used for landing without the risk that the machine will touch tail first. In fact, at any other position of the control at the moment of touch-down the result can be a slight but harmless wheeler.

Frankly, I cannot for the life of me see why anybody should find any serious difficulties in either the flapped approach or the landing itself, though one or two pilots appear to have succeeded in breaking the unfortunate aeroplane by tactics similar to those of a badly trained soloist, and others, upset perhaps, by their nearness to the ground at the moment of landing, have failed in their attempt to break the machine by dropping it from considerable height. Nobody, however have been hurt.
My own reactions, as a very normally experienced amateur, is that Messrs. Ward, Dalrymple and others must have been singularly unlucky in their encounters with interested amateur aeroplane tasters. Both Ward and Dalrymple flew the machine safely and successfully after about 50 hours solo on other types - and neither of them would pretend for a moment that they were born birdmen or any nonsense of that sort.

Undoubtedly, on a cross flight, the pleasantest feature of the Chilton is the extraordinarily good view obtainable from the cockpit. This excellence, coupled with the machines general controllability, possibly provides the only real source of danger to the person who actively enjoys flying, one is sorely tempted to fly at aero altitude, and even the best of eyes occasionally miss such obstructions as power pylons and chimneys. However, a resultant write-off could not be considered as a fault of the machine. The screen is a perfectly normal one, yet by chance or otherwise there is practically no draught and for nearly an hour I flew without goggles, which are only necessary when one’s head is popped out of one side or the other for some reason.

The structure is perfectly conventional and much stronger than is actually necessary for the stresses likely to be imposed. The ply for instance, is certainly thicker than stress considerations require. Anybody who has seen Mr. Porteous demonstrating the Chilton can have no doubts about either its controllability or its strength. Encouraged by the sight of his evolutions I even went so far as to do a couple of loops myself. The available power, though more then adequate for normal purposes, is of no particular use during such a manoeuvre and it is necessary to obtain a little more than 130 m.p.h. if one is not to risk dust and fuel discomforts resulting from a suddenly reversed load at the top of the circle.

Although the Chilton is produced in standard form with the modified Ford engine it has been stressed to take any unit with a power of 50 h.p. or less. The calculated figures for the machine fitted with, for instance, a 44 h.p. inverted Train engine, include a maximum speed of 125 m.p.h. and a cruising speed of 112 m.p.h., the rate of climb is then 1,000 ft/min against the standard figure of 650 ft./min., and with this engine extra tankage can be arranged for a non-stop range of 1,000 miles. In the normal form the Chilton has the very adequate range of 500 miles.

“Indicator”

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More Power For The Chilton

Fighter-like Performance for Train-engined Version - Unchanged Characteristics

Flight - 24th August 1939

Quite a number of pilots, both experienced and inexperienced, have now flown the little Ford engined Chilton single seater. Those who have not been initially terrified by the somewhat diminutive size of the machine, and those who have had the opportunity, in any case, to get to know it, all agree that it is by way of being a very remarkable little aeroplane. Not only are the handling qualities exceptional at all speeds, but the machine is reasonably vice-less and, even with the low power to weight ratio of the water-cooled Ford engine, the take-off run is short, and the climb safely useful.
Judging from the manufactures experience, there is no need to feel any doubts about the capacity of the Ford engine, both in the matter of long distance reliability and performance holding. In fact the Chilton has shown designers what can be done even with an engine which can hardly be considered as efficient from the flying point of view.

However, those who want a real aero engine can now buy the Chilton with a 40 hp Train engine. Though giving more power, this engine is actually lighter than the Ford and, to mention a superficial and unimportant matter, has considerably improved the lines of the machine. The Train 4T engine is an inverted four-in-line air-cooled unit, the most interesting feature of which is the over-head (or under-head) camshaft, which is driven by bevel gearing directly from the rear of the crankshaft. The maximum rated output is 44 hp at 2,350 r.p.m., and the Chilton people, who partly disassembled their first example, say that it is very sturdily built. Dry, the Train weighs a little over a 100 lbs., against the 130 lb. Of the converted Ford engine - which delivered a maximum of 33 hp at the less airscrew efficient speed of 3.500 r.p.m.

Without actually leaping straight from the Train engined machined machine to the one with the Ford engine, and there was no example of the latter available when I flew the new type, it is not possible to say that the new engine makes no difference to the handling characteristics. Certainly, however, these seemed to be just the same, though the lower weight of the new engine may possibly have very slightly altered the stalling characteristics. These are still safe enough, but the full stall arrives a little more suddenly and the left wing drops away. The Ford-engined version stalled on a level keel.

Needless to say, the new engine makes a considerable difference to the performance. In the Folkstone Trophy race three weeks ago the prototype averaged 126 m.p.h. round the triangular course with a 15 m.p.h. wind blowing. Allowing for the fact that Mr. Dalrymple probably dodged the wind as far as possible, this figure, with the necessity for tight turns, means that the ordinary maximum is at least 130 m.p.h. On the airspeed indicator, which had been checked, the machine cruised (2,050 r.p.m.) at a little over 110 m.p.h. at 2,000 ft., after making allowance for height error, this gives a cruising speed of about 115 m.p.h. - which is certainly quite good enough on a great deal less than 40 hp.

During a trip from Marlborough to Lands End, back to Hungerford and Marlborough, with a great many sight-seeing deviations, pauses for minor aerobatics and an unswung compass, the crow flying distance of 415 miles was covered, including take-offs, circuits, climbs, descents, and landings, in an inclusive time of 4 hr. 25 mins. This provides a good steady 96 m.p.h. out and 92 m.p.h. home. The fuel consumption worked out at less than 3 gallons an hour, which tallies fairly well with the official figure of 2.75 in ideal cruising conditions.

Most remarkable of all however, is the initial rate of climb. The maker’s give it as 1,000 ft. per minute, and without a stop watch it was not possible to check this figure. However I found that just four minutes was taken to climb to 3,000 ft. on full throttle without seriously attempting to hold the best climb speed. Curiously, enough - though the fact may be an illusion - the take-off run does not appear to be very much shorter than the Ford engined version.
Obviously, with more power and more effect airscrew it must be , and the probability is that the rather higher cowling line and the slight initial difficulty in settling the machine down on a straight course during the take-off contribute towards this affect - in other words, I was not making it fly as soon as it could have done. Not unnaturally, there is a fairly pronounced swing to the right during the take-off. This does not occur when the throttle is first opened, but as the machine gathers speed and the airscrew becomes, consequently, more efficient. There is ample rudder to correct the swing, but newcomers should be prepared for it, and try not to take-off in a series of over corrected swerves. Actually the undercarriage is so wide that it is difficult to imagine that any catastrophic results would occur even during the most careless and unhappy departure.

The majority of my take-offs and landings were made from the Earl of Cardigan’s little field, which is used by Chilton Aircraft as their nearest landing ground to Hungerford. The ground there is distinctly rough - so much so that a passage over it in a car at 30 m.p.h. is a terrifying and back braking experience. But this field, with its odd approaches and small dimensions, at least gave a very good idea both of the safety of the take-offs and of the initial climb, as well as the way in which the Chilton can be bought into a spot landing without the use of any such old fashioned aids as side-slipping. The split flaps on the machine have half a dozen positions, and the best way of graduating an approach is to go round in gentle turn while applying more and more flap as conditions appear to demand.

In five approaches and landings in flat calm conditions over a useable run of rather less than 400 yards there was never any necessity to use the motor or to go round again. It is quite safe to glide the Chilton at a little more than 50 m.p.h., gathering perhaps, a little more speed before final touch-down, though in windy conditions either more speed or less flap should be used. The more efficient airscrew, even at tick-over speed, tends to extend the landing run, but there should be no need to fit brakes to this version of the machine. On the ground in ordinary conditions (there was a 15 m.p.h. wind blowing at another aerodrome visited), it is fully controllable on rudder and slipstream alone, and only with half a gale would it be necessary to have someone on the wing tip.

There is no need to emphasize the remarkable handling characteristics of the Chilton, since these are much the same as before - though the additional power gives aerobatically inclined pilots a chance to carry out some fairly extreme manoeuvres without loss of height.
This fact has already been shown at one or two flying meetings. But it is, perhaps, necessary to mention once again the tidiness of the layout. Though extremely small, the cockpit allows ample room, and everything is placed where it should be placed. Furthermore all of the fittings are rigidly attached, and even the necessary pipelines and other items are neatly installed and do not obtrude. Other light aeroplane manufactures may usefully glance over the Chilton.
It is both possible and practical to fly the machine without goggles, though advisable to use them during take-off and final approach, as it is then sometimes necessary to look fairly well out beyond the little screen. There is a usefully large luggage locker immediately behind the seat in which any ordinary case or cases can be strapped. There are map holders on each side of the cockpit. Finally the Chilton designed aerobatic harness may also be used as a lap-strap for normal flying.

Tony Taylor

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Chilton light monoplane - General flying instructions

The following are the flying instructions issued by Chilton Aircraft:-

A large proportion of the following instructions are in no way special to the Chilton, and would not be considered worth mentioning except for the fact that there are many differences of opinion on the subject of monoplane flying technique, which is not yet standardised to the same extent as the flying of the older conventional flying club biplanes.

Take-off.

Like most other low wing monoplanes, the Chilton will not take off of its own accord but must be gently eased off the ground after a suitable distance has been covered. The air speed indicator does not give good indication of when this point has been reached, which must be decided by one's own judgment, taking into account both strength of wind and load carried. If the aeroplane starts to bounce during take-off run, violent corrections should be avoided.

Climb.

Stalling speed without flaps is 40-42 m.p.h.

Steepest climb is at about 45-48 m.p.h.

Fastest rate of climb is at 60-65 m.p.h.

It is usually best when taking off to start to climb at a speed of about 50 m.p.h. but then to let the speed gradually rise to about 60. One should not climb at the lower speeds until used to the machine, and the airspeed must in any case be watched very carefully. When taking off from a small space it appears to be better to climb steadily as soon as a safe speed has been reached, rather than to keep the aircraft low, gain speed and zoom. This is especially true on a windy day when the slower and steeper one climbs the more assistance one can obtain from the wind

General

Flying In bumpy weather any small aeroplane gets tossed about more than a large one. In the Chilton it seems best to make practically no conscious effort to correct bumps, when one rapidly ceases to notice them. In actual fact, owing to the reasonably heavy wing loading and also owing to its low build, the Chilton can be used in quite strong wind and under conditions when most other light aircraft would risk being blown over.

Cruising speed

There is a considerable difference between individual propellers as to the number of revs per minute required to give the same cruising speed. Generally speaking it is best to keep at least 300 revs below the maximum obtainable. 100 revs makes a very large difference in the power being taken from the engine, and consequently in the petrol consumption. The normal power output at cruising speed is 23-24 h.p., and the corresponding fuel consumption is usually 1.7-1.8 gallons per hour. Consumption at full throttle is about 2.75 gallons.

Indicated cruising speed will usually be less than a 100 m.p.h. For true air speed add 11/2 m.p.h. for each thousand feet above sea level.

Approach and Landing

The normal type of approach, carried out with flaps down throughout, seems to be the easiest, although some pilots prefer to approach without flaps and put them down just as they reach the aerodrome boundary. Others make a habit of undershooting and motoring in on the engine. This is a very easy method and is standard practice on multi-engined aircraft with high landing speeds. It is not however, necessary or desirable on a light aeroplane with a low landing speed. In any case, the secret of getting an accurate approach is the use of a steady and constant gliding speed. The Chilton can be side slipped effectively, but with flaps down this is never necessary, as height can be lost very effectively, by gentle gliding turns.

Under forced landing conditions or whenever a really accurate approach is required, the following is recommended. Apply flaps half-way and make a very careful approach at a steady gliding speed of about 50 m.p.h. The final hedge or other obstruction should be passed over as close and as slowly as can be judged with safety, and the flaps should at that moment be applied fully. By this method it should be possible to come to a standstill about 100 yards beyond a normal sized hedge or fence.

The best approach speed under normal conditions varies from about 50 m.p.h. on a calm day to 60 m.p.h. in quite a strong breeze. The life of the flaps will be considerably prolonged if they are never used at speeds of more than 60 m.p.h., though no actual harm is likely to be done at speeds under 70. The use of the flaps in their fully down position is not recommended when landing in either a very strong wind or up a steep slope.

As regards the landing itself, it is perhaps better to make wheel landing rather than a dropped one, as there is a little tendency to bounce in a flapped machine. Should one wing drop as the aircraft stalls, apply opposite rudder. At this very low speed the rudder is more effective than the ailerons.

Mixture (Altitude) Control At heights of 3,000 ft. and over, the engine may show signs of a rich mixture either by misfiring or by black smoke from the exhausts. The mixture can then be weakened by careful use of the control. This should not be pulled out any further than necessary, and should on no account be allowed to cause a falling off of the engine revs. This would indicate that the mixture was far to weak and might cause overheating or serious damage. It is essential that the mixture control be closed before closing the throttle. Otherwise the engine might stop whilst gliding down or landing.

(a) Starting the engine when cold

1. Pull out the choke control to close fully.
2. Retard ignition by pulling out the control slightly more than a quarter of an inch.
3. Open throttle about 1/16".
4. Suck-in by turning propeller over 8-12 compression's.
5. Switch on left (retarded) switch.
6. Swing propeller smartly to start.
7. Push in choke immediately.
8. Advance ignition and switch on both mags.

Most people find it easier to switch on both mags immediately, and not bother about turning one off. The engine starts better this way, but there is more tendency for it to kick unless it is swung very sharply

In cold weather these engines like the mixture to be very rich indeed, and like to have the propeller swung as sharply as possible. If the mixture becomes to rich, the engine will indicate this by sneezing. If it does this twice consecutively, or chokes out after starting, open choke fully and the engine will nearly always start if swung again without delay.

If the mixture becomes altogether to rich, switch off, open the throttle and suck out the mixture by turning the propeller backwards over about 8 compression's in the usual manner. Then start again as before.

(b) Starting engine when warm.

1. Pull out choke fully.
2. Open throttle about 1/16".
3. Suck in by turning the propeller over 4 compression's
4. Push in choke.
5. Switch on.
6. Swing propeller smartly to start.

(c) Starting engine when hot.

1. Set throttle.
2. Switch on.
3. Swing propeller sharply to start.

Method (c) is really only used in warm weather or when the engine has only been stopped for less than a minute.

It is advisable always to use chocks when starting the engine, and also to see that the control column is not right forward.

If starting becomes difficult, check contact breaker points and sparking plugs. Set plug gaps to 0.014". The engine starts better on both magnetos and fully advanced, but tends to kick if swung to slowly

Engine Temperature:- The water temperature under cruising conditions varies from 80 centigrade in winter to 90 - 95 in summer, and shows little tendency to vary widely from these figures. When gliding down from a considerable height, it is desirable to give a short burst of throttle every 2,000 ft.

Oil:- Only light grades of oil should be used of viscosity S.A.E. 40 in summer and S.A.E. 30 in winter. The latter is unfortunately seldom obtainable at aerodromes, owing to the use of air cooled engines. The pressure when cruising should be 20 - 25 lbs/sq.ins.

The capacity of the sump is just over 1/2 a gallon. The dipstick is marked with an F (full) and an L (low). These are the Ford markings and are only correct if the level is taken with the aircraft in flying position. There is nearly 2 pints difference between these two marks.

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Sporting Flying

A Single Seat Train-er : Good looks on a small scale

The Aeroplane - September 7th 1939

The Train motored Chilton looks like its predecessors but is even cleaner in the nose cowling and also happens to have a very high finish. These things, and the general scale and clean lines of the machine, can be well seen in this picture. Soon after the victory of the Train motored Chilton Monoplane in the Folkstone Aero Trophy Race I flew it, by courtesy of its parents and guardians the Hon A. W. H. Dalrymple and Mr. A. R. Ward.

The 30 hp Carden Ford motored Chilton I knew of old and admired. As the air cooled four in line Train is lighter than the Carden Ford and 25% more powerful I hoped to find all the Chilton Merits intensified accordingly. The machine itself is quite unusually good, orthodox with being ordinary. Its performance on 30 hp and its general handling are remarkable.
The Train motored version is a most attractive little machine, highly finished in Black with white trimmings. The cockpit is a bit compact for a large person but quite comfortable. The luggage locker is behind the seat, which hinges forward to get at it. There is also a shelf for small articles behind the pilots shoulders and two map pockets beside his calves.

There are no wheel brakes and steering on the ground is not quite so easy as with the Carden. More motor is needed and the rolling speed tends to go up. One gets a foretaste of the general liveliness. The tail comes up at once when the motor is opened out. Queerly enough the take-off is not what one might expect from the extra power and larger airscrew. Small airscrews are very critical of the smallest variations and another may give very different results. The best I could do was 120 yards, but it should be under the 100.

The climb is excellent, the weather was rough and the ceiling low, but I think 750 ft. per minute a fair estimate for full load.
Some people object to light controls and lively response, and the Chilton will not be their choice. On the other hand it has no vice whatsoever, and as supremely controllable aeroplanes have a proportionate capacity for rousing affection the little Chilton is already gathering a band of enthusiasts. I incline to be one of them.

So small a machine naturally gets tipped about in rough weather, perhaps not more than a larger, but more abruptly. If one lets the Chilton do its own wallowing the motion becomes much easier. At first I failed to realise it flies itself quite reasonably, through leaving the stick just off centre.
What little control friction there is, is then enough to prevent the dihedral from being fully effective. There is not enough dihedral to make good turns on rudder alone. Directional stability is very good, and turns on the stick, with feet off the rudder bar, are steady and accurate. The outlook is excellent, for the nose is fine and neither it nor the wings cut off any important amount of view.
The windscreen is small, but flying without goggles is comfortable provided no attempt is made to look round it. There is no necessity for that, even in rain.

The craft averaged 126 m.p.h. in the closed circuit course Folkstone race at an air-speed reading of 135, so the error cannot be great. At normal cruising r.p.m. of 2,050 the reading was 110, and the throttle was more that half closed to produce these figures. The consumption is said to be slightly more than two gallons per hour, so the mileage is cheap enough.
In bumpy air the stall without flaps seemed to be about 50 m.p.h. and with the flaps about 40. In one patch of still air gliding turns at 45 m.p.h. were quite comfortable. The flaps operate mechanically, without much effort, are powerful as brakes and do not change the trim.

The feel of this machine gets one into an aerobatic frame of mind which is improper under low bumpy clouds. When a clearing appeared I went quickly to 3,000 ft. to start with a loop. When just nicely into it I remembered that the 40 m.p.h. stall which I had in mind, was with flaps, so perhaps 110 was to low a starting speed. In absent minded eagerness to get over the hump I drew a bit more G with the lively elevator, thereby raising the stalling speed to 60 m.p.h., at which reading I was precisely upside down.

That piece of ham-handedness and ham-wittedness bought its own quick cure for misguided exuberance. The Chilton did a brisk flick roll upwards into an horizonless world. The behavior of aeroplanes in spins leaves me cold, but for the readiness of the Chilton to stop spinning I have the warmest approval. Not having spun involuntarily for some years I realised later that it was a refreshing experience at 3.000 ft. Incidentally I have seen this machine do all ordinary aerobatics very charmingly.

The Marlborough aerodrome of Chilton Aircraft is conviently athwart the railway line, which enters a tunnel just there and brings the Bradshaw-pilot in much more certainly than a VHF beacon. It is not Hunterised, and slopes in several directions to fences which I find too near. A south wind blows over it into a valley and makes a down-draught which wafts the casual visitor temporarily out of sight below, whence he emerges at full throttle to drop over the fence among the haymaking.

The impression is perhaps rather jaundiced, but the Chilton made no difficulty about its native sod. It had been there before, whereas I had not.
The empty weight is 385 lbs. And the all-up weight 650 lb. The difference accounts for a pilot of reasonable weight, 10 gallons of petrol and ordinary luggage. The range is more than 400 miles at over 100 m.p.h., to be conservative. More than one single seater has been produced which did very little more on twice the power, and sold for much more than the £375 which the Chilton (Train) costs.

F. D. Bradbrook

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Train Aero Engines

Translation from the French Radio Contact Aviation - May 1936

Following too many flying incidents and accidents in the new-born aviation, due to engine failures, it appeared to me as a basic question for private aviation to find a reliable engine, easily maintainable, of low cost, of low fuel consumption, for if the amateur demanded an authorisation for the engine as for the airframe, I asked for the exclusive use of approved engines, for the reason that many pilots were saved by there engine and more numerous still that killed themselves due to mechanical failure at a critical moment. And although this note is several months old I thought that it would be useful to all people interested in flying more especially as the TRAIN 40 CV is engaged in the Augers 24 hour race (1936) by different constructors, we will be able to judge from an approval on the test bed that would otherwise have to be approved in flight I will return to this question later.

A telephone call told me that the first engine for general aviation was in the process of finishing its approval tests and it is why I proceeded to Courbevoie, in order to attend the last C.I.N.A. approval test of the 40 CV engine.
Four inverted cylinders specially designed for aircraft by the old established firm of "Etablissements Train". It is the first engine approved from the well known family of engines comprising 2 cylinder, 4 stroke 20 CV; 4 cylinder 40 CV; 6 cylinder 60 CV commenced by this firm.

Received by M. Train I explained the object of my visit.
"The engine that you have come to see running", he told me, "is on the point of finishing its approval tests. Up to the present it has successfully passed all the different tests, power, slow running etc. and at present it is finishing its 50 hour endurance test".
The needle of the rev-counter, that I am looking at, seems to be stuck at 2,300 revs. The inspector of the S.F.A. records on an official test sheet the readings, every ¼ hour, on the different instruments on the test bed as well as the consumption's.

It is not the rush of air or the deafening noise of the exhausts, nothing betrays the operation and my hand resting of the test bed feels no abnormal reaction. The engine exhibits the correct characteristics for one that has run for 50 hours.

Here are some figures recorded on the official bulletin:

Nominal Power : 40 CV at 2,300 rpm
Actual Power : 44 CV at 2,300 rpm, the recorded rpm varies between 2,300 and 2,307
Fuel Consumption, min : 227 grams per CV hour - max. : 234 grams per CV hour
Oil Consumption, min : 9 grams per CV hour - max. : 13 grams per CV hour

M. Train invites me to have a look at the manufacture. There, I watch the machining of the cylinders carried out on automatic lathes that receive the die-cast rough parts in the form of a tubular steel billet weighing about 17 kg's, and when completely turned is reduced to a weight of 1,600 grams. It is then, 15 kilos 400 grams that the different automatic lathes must remove from each cylinder. If we take into account that the cylinders are nickel-chrome steel, heat treated to a tensile strength of 110 kg, we realise how much metal must be sacrificed in making an operation long and costly to obtain lightness and strength. It is the same for all the parts that I saw machined. To obtain lightness, it is necessary to use high strength steels and to machine it out to the least recess to achieve all that is absolutely necessary regarding the rigidity of the part.

The crankshaft is a one piece high strength steel stamping that is completely machined. The 4 crank-pins and the 5 bearings are drilled and bored, the webs are milled so that all unnecessary material is eliminated. In comparing the 4 cylinder crankshaft "Train Aviation" with the one for the same capacity car engine we realise that the price of the "Aviation" crankshaft is 5 times that of the "automobile". Also it is not surprising that the "Aviation" engines are, in general quite lightly priced.
The design of the engine is based on numerous inverted in line engines built as much in France as overseas, such as the Gypsy engine for example, the type of engine that has proved itself in aviation and has bought to it certain refinements such as control of the valves by overhead camshaft.

It is then a 4 cylinder inverted inline engine with a total capacity of 2 litres, air cooled with a forced air flow to the rear cylinders. It weighs a total of 48 kg's. including the propeller hub. The fuel mixture is supplied via a AMAC carburettor and ignition is by a S.A.G.A magneto. On request the engine can be provided with twin magnetos. The oil circulation is ensured by the high capacity pump; all the parts such as the valves and seats are pressure fed. They are controlled by an overhead camshaft of a new design that it is not permitted to describe, the crankshaft runs in 5 bearings and the con-rods of die cast duralumin (alloyed with antimony). The whole is supplied with the oil to the tinniest detail.

Being very communicative with M. Train, I left the machine shop to go to the assembly building. Around me the fitters busied themselves with the meticulous care of the engines. Some work on the assembly of certain sub-assemblies, such as those including the crankshaft and con-rods, whereas others finish the assembly of the complete engine before running in. A certain number of aviation engines are in the course of assembly including the 2 cylinder 20 CV, the 4 cylinder 40 CV and the 6 cylinder 60 CV, constituting a complete range of engines for light aviation.

"The engines you see in the course of assembly" M. Train told me, "these are destined in part for aircraft manufacturers for their tests and on the other hand, as we want to be able to deliver rapidly the engines that have been ordered from us, it is necessary that before increasing sales, we would make a drive and would deliver in the first place the orders that we have in hand".
"Finally, we only want to sell the engines of which the prototypes have been approved and you can say no aviation engine will be sold if it has not been accepted by the official authorities, according to the acceptance conditions of the C.I.N.A., normal category. This guarantees that the engine delivered conforms exactly to the approved prototype".

The judicious reasoning reminds me that the 'Certificate of Air worthiness' and the obtaining of the first sale, if it is to be maintained, can only succeed if the engine with which the aircraft is equipped has been approved. The Air Minister in his wisdom, has given temporary authorisation for flights of certain aircraft fitted with non-approved engines, because he did not want to slow down the development of popular aviation, but to avoid serious accidents only aircraft with approved engines will be able to fly in France and the users will not be able to reproach "Etablissements Train" for having sold them an engine that is not approved.

M. Train, that was in his time a forerunner of aviation, built his first aircraft in 1911, reckoned at lengths that if a car or motor cycle engine could at a pinch have some minor faults, it is not the same for the aircraft engine which must be delivered to the user perfectly run in and be absolutely reliable. The least imperfection, such as the tightening of a piston or a momentary slight loss of power could be the cause of grave or possibly fatal accident.
The official and rigorous inspection of the manufacture of aero engines, now in effect, is indispensable for all engines, if we want to avoid accidents prejudicial to light aviation. Passing in front of the test house, the 4 cylinder engine had just been stopped after having successfully completed its 50 hour endurance test.
Impressed with what I had seen, especially with the conscientious way in which the work was carried out by "Etablissements Train" I promised myself to return to see the 20 CV twin cylinder which will be a good engine for aviators and aviator mechanics.

Alege

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Popular flying 1938

An Economical, High Performance Monoplane,
Powered by a Converted Motor-car Engine

The lower the cruising speed of an aeroplane , the greater the effect of wind speed on the mileage that the aircraft will cover in an hour. If the cruising speed is 60 mph, a wind speed of 30 mph will give the aeroplane a ground speed of 90 mph when it is traveling with the wind. Against the wind the ground speed will only be 30 mph. This speed is less than that averaged by the majority of cars on the road and is of little use for air touring. An aeroplane with a cruising speed of 100 mph would be able to cover the ground at 70 mph even against a wind of 30 mph. The percentage increase in speed when flying with the wind would not be so great with the faster aeroplane, but the more practical aircraft is the one that is able to maintain a reasonable speed whether it is high performance of an essentially useful aircraft, apart from the economy of its maintenance and running costs. Many ultra-light aeroplanes are designed as an expensive means of getting into the air for local flying. The object behind the Chilton monoplane, which can correctly be called an ultra-light aircraft, was to design what the makers described as " a real aeroplane in miniature".

Aircraft of the Chilton type and other similar single seater ultra-light aeroplanes are exempt from the normal Certificate of Airworthiness procedure applying to all other aircraft. This cheapens their construction and maintenance, because adjustments and repairs do not have to be carried out by engineers holding Air Ministry licences. The question of safety of this class of aeroplane is left in the hands of the company which underwrites the necessary third party insurance. Third party cover is required before the Air Ministry will issue registration letters for the aeroplane. The insurance company is naturally careful to insure that the aircraft covered is competently built and designed. The Chilton Monoplane is a low wing aircraft with a four cylinder engine, spats and split trailing edge flaps. Aircraft of this class are not officially permitted to perform aerobatics, but the Chilton Monoplane, to ensures complete safety, is stressed to a degree suitable for aerobatics. It is of wooden construction, with plywood covering for the greater part of the wings and fuselage, the control surfaces are fabric covered.

The speed ratio of 3.3 to 1 is obtained with the aid of the flaps, which permit a landing speed as low as 35 mph. The maximum speed is 112 mph and the cruising speed is 100 mph. The use of the flaps also steepens the glide of the aeroplane which because of the clean design, is particularly flat without the flaps in use.

There are intermediate positions for the flaps between closed and fully down, and they may be moved during the glide to control overshooting or undershooting when approaching the aerodrome. The flaps start at the ailerons on either side of the aeroplane, and are continuous for their whole length passing underneath the fuselage. The flaps are not used during take off which is however, as short as 80 yards. The landing run is only 50 yards. The fuel consumption is 1 ¾ gallons per hour when cruising at 100 mph, and the running costs are estimated at less than a halfpenny a mile. The range of the aircraft in still air is 500 miles. The wingspan is 24 ft. the length of the aircraft is 18 ft. and the height is 4 ft. 10ins. The unusually wide track of 6ft. for a small machine assists stability when landing. The wing area is 77 square ft. with an all up weight of 640 lbs. gives a wing loading of approximately 8.3 lb to the square foot. Although the maximum all up weight is 700 lb., 640 lb. is the maximum normally desirable. This weight is made up as follows: weight of aeroplane empty 395 lb. pilot 160 lb. luggage 20 lb. and fuel 65 lb. There are four inches of spring travel for the wheels, which have low pressure tyre, the tailskid is sprung. The control cables are enclosed and the ailerons are fully differential. That means that when the stick is put over towards the right, the left aileron is only slightly depressed, while the right one is raised considerably. There is thus, for example, little of that aileron drag to the left which would tend to turn the aeroplane in a direction opposite to that desired when a turn to the right is made.

The engine unit is a converted Ford 10 engine. This is a water cooled, four cylinder, four stroke unit. Dual ignition is fitted, and the developed horse power is 32 at 3,500 rpm. The engine is fitted in an upright position in the nose of the aircraft, with four short exhaust stubs projecting through the right hand side of the cowling. The radiator is fitted immediately below the engine, an oval opening in the front of the cowling allowing the air to reach it. The weight of the engine is 141 lb. including the two magnetos, the airscrew hub and eight sparking plugs – two to each cylinder. Many of the parts of the engine have been altered. An aluminum head is fitted and also a special crankshaft with heavy duty ball bearing to take the thrust of the propeller. A number of subsidiary light alloy castings are used to reduce the weight. The bore of the cylinders is 63.5 mm and the stroke of the pistons 92.5 mm, this gives a total engine capacity of 1,172cc.

Although the cockpit appears small from the outside of the aeroplane, the pilot finds there is ample room when he is seated. The cockpit is comfortable and well protected by the windscreen. Two of the features first noticed when the aircraft is taxied is the smoothness and comparative quietness of the engine. These qualities are largely due to the high number of revolutions a minute at which the engine develops its maximum power. Taxying is particularly easy, the aircraft answering the rudder almost as though wheel brakes were in use, the wide track makes sudden turns quite safe.

Like the majority of clean, low wing monoplanes, the Chilton requires an easing back of the stick to lift it off the ground as soon as flying speed is attained. With the tail up in the position of level flight, the view from the cockpit is good and encouraging for a pilot with but little experience. In spite of the high performance of this aircraft, it is not designed as an expert’s aeroplane, it has a sensitive response to the controls, but is easy to fly. The throttle works in the opposite direction to those on most British aircraft, it is pulled to open and pushed to close. Pilots who are used to the orthodox arrangement, however do not find this disconcerting, because the shape of the Chilton control is unusual. Instead of being a knob topped lever, it is a disk shaped button on the instrument panel. The best climbing speed is about 60 mph after the aeroplane has been cruising level at 100 mph, the nose of the machine has to be pulled up surprisingly high before the speed drops back to this figure. At this speed the monoplane climbs at a rate of 650 fpm.

All the controls are powerful and response to them is immediate. Side slipping is possible, although it cannot be performed as steeply and slowly as on, say, a training biplane. This however, is normal with a clean monoplane, and is no drawback when flaps are provided which have four different positions. These provide the best way of shortening or lengthening the glide of the Chilton during an approach. Without the flaps in use the aircraft will glide flatly and would float a long way across the aerodrome before a landing could be accomplished. With the flaps fully down the rate of sink is rapid and the forward touch down speed slow. The two intermediate positions provide an advanced form of glide adjustment which is not found, even today, on a great many full size and expensive aircraft.

If the aircraft is bought in slowly with flaps down, the landing has to be made quickly at the end of the glide because of the rapid sink. Most pilots find the machine easiest to land when the flaps are right down, and they bring it in faster than necessary, or if they bring it in with the flaps set in the position before the fully down one. It is largely a matter of the type of aircraft with which the pilot if familiar. In a single seat aircraft the pilot has to find out the landing characteristics for himself, because no dual instruction is possible. But several pilots with well under fifty hours solo flying experience have successfully flown the Chilton Monoplane. The wing construction is of the cantilever type with two box section spars. The wings are in three parts. A centre section with parallel leading and trailing edges is let in to the underside of the fuselage and has the undercarriage attached to it. The two outer panels are tapered and are detachable from the centre part. The fuselage is a semi monocoque ply covered wooden construction with spruce longerons. The cross section of the fuselage is rectangular, with rounded top ply decking. In the same way as the throttle control, the rudder controls are unusual so far as most power aeroplanes are concerned. The rudder controls, of the pedal type, are hinged to the floor of the cockpit, and are similar to those often used on sailplanes. It is unusual features such as these, both visible and unseen, which give the Chilton its individuality. The aircraft is the successful outcome of an attempt to produce a safe, high performance monoplane with a low powered engine. Two young designers, the Hon A.W.H. Dalrymple and Mr. A.R. Ward, were entirely responsible for the design of the Chilton Monoplane. Both had previously studied aircraft design and construction at the De Havilland Aeronautical Technical School at Hatfield, and the Chilton aeroplane is the first one to be built to their designs. Work on the design was begun early in 1936, and in May of that year the firm of Chilton Aircraft was formed to build the prototype machine. The prototype was flown in April 1937 and work on the production models began soon afterwards. In August 1937 the firm took over the production of the Carden Ford aero engine – the unit with which the Chilton Monoplane is powered.

The aircraft has been designed to be strong enough to take power units, other than the Carden Ford, with horse power up to 50. The designers have considered fitting a 44 hp inverted Train engine. It is calculated that with this engine the cruising speed would be increased to 112 mph and the maximum speed to 125 mph. The climb is calculated as an extraordinarily good figure of 1,000 fpm.

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Carden Aero engines

Carden Aero Engines was formed in 1935 by Sir John V. Carden Bt., Technical Director of Vickers-Armstrong, who's name is associated with Carden-Lloyd Tanks, Tractors and Carden Light Cars. After the death of Sir John in an airline crash in December 1935, the company was taken over by Carden-Baynes Aircraft Ltd. In 1937 it was acquired by Chilton Aircraft, which produced the engine for its own needs. The engine is a four cylinder four stroke which has as its basis the 10 h.p. Ford Model 'C' type automobile engine.

The following is a copy of the Carden Engines sales literature:-

The first Flying Flea to leave the ground in England was Carden engined and has since been proved to have an appreciably better performance than the French original.

Reliability

In the past the amateur builder, when and where permitted, had a difficult time of it with unsuitable engines, so a superstition has grown concerning most sporting types of aviation to the effect that forced landings must be expected and do not matter providing the machine is easy to fly and lands slowly. This is wrong, no aviation whatsoever can tolerate unreliable engines.
Fortunately reliability can be achieved nowadays without the great cost of a specially designed aero engine. The modern motor car whatever its price, is a miracle of efficiency and dependability mainly because the huge output of the popular makes and severe competition, both enable and oblige the manufactures to spend millions on research and development. Their engines can be adapted to the air requirements and by this simple means aviation reaps the benefit of more time and money in development than has gone to the best specialised aero engine in the world.
The name Ford is deservedly world famous for outstandingly reliable motor cars at low price. The general design and a number of parts used in the Carden engine are those of the 10 h.p. Ford. This power plant delivers its 30 h.p. at 3,300 rpm, on the road these revolutions can be maintained for days on end and failure is almost unknown among thousands of cars. In the air its cruising speed is 3,000 r.p.m., the load and revolutions being practically steady, thereby giving the engine and its bearings ideal conditions in which to work. Four cylinders provide the safety factor of a reserve of useful power in case of a failure in one cylinder. With less than four cylinders, failure in one spells the finish of all propulsion, whereas three out of four are still useful to stretch the glide and negotiate a landing. The use of many Ford parts is a guarantee of low price as well as good quality.
The Carden engine costs £51-10-0 including the airscrew hub. Owing to its design it requires no special engine bearers and as the oil is carried in the sump no separate oil tank and connections are needed. A suitable radiator, water pump and connections cost £3.10.0 and the airscrew, which is directly driven costs £5.0.0 The total of £60 for a completely equipped propulsive unit cannot be equalled for anything like the equivalent assured performance and staying power. Dual ignition is somewhat rare in such a small engines, but a second magneto, plugs etc. can be supplied for an extra £8.10.0

Installation

The self contained engine is bolted directly to the wooden fuselage and no metal bearers or mounting are required. The radiator can be mounted wherever it is most convenient and connected on with suitable hose, as a built in pump assures water circulation whatever the radiator position chosen.

Maintenance

The Ford engine is designed for hard and continuous work in unskilled hands, so frequent top overhauls are not required. When however they do become necessary, the sidevalve design and the easily removable alloy cylinder head makes the operation quick and cheap. Such parts as pistons, valves etc. are standard Ford components and are therefore cheap and universally obtainable.

Weight

In assuring complete reliability concession has been made in the Carden engine in respect of weight. In its present form it weighs 145 lbs dry and with radiator and connections and water this figure works out at about 160 lbs. Further reductions will be made gradually, but in the meantime there are savings in compensation, such as direct drive airscrew weighing 2 ¾ lbs., no separate oil tank, no special metal mounting, and a low fuel consumption which does much to balance the extra weight of the water cooling which makes it possible.

Running Quality

Years of research and expenditure have been devoted to making the motor car engine as extraordinary smooth and quiet as it is today. To see and hear the Carden engine in an aeroplane is a revelation to those who are accustomed to more orthodox types and has caused much astonished comment. Even with its usual unsilenced exhaust of an aero engine it is remarkably quiet, and only those who have known the nerve racking effects of long journeys behind open exhausts will appreciate this merit at its true value. The four cylinder design naturally has overwhelming advantages for quiet and smooth running compared with fewer cylinders.

Starting

Light and easy starting is combined with a perfect and silk smooth tick-over.

Some applications

The Carden engine lends itself to the design of a variety of types.

High efficiency single seaters will produce excellent performance on 30 h.p., and many designs have been produced to give 100 m.p.h. sometimes more. An example of this is the "Tips" designed by Mr. Tips of Fairey Aviation Co. Belgium which has a speed of 90 m.p.h. on about 25 h.p. The lack of a suitably designed and reasonably priced engine has prevented the wider use of such types with modern devices for additional efficiency.

The excellence of the pusher type of aircraft for pure pleasure flying, particularly with its perfect forward view is combined with low wing loading and easy flying qualities, provides a big opening for the quiet and reliable Carden engine. The B.A.C. Drone is a good example of this type of aircraft, and the engine ideally adapted for it.

Amateur built single seaters are typified by the famous "Pou du Ciel" or "Sky Louse". This is the best known design for amateur building, combining great simplicity, rugged strength and inherent safety. Possessing these three qualities in outstanding degree the Carden engine is the perfect power plant for such aircraft and its ample out-put compensates for the lack of sheer aerodynamic efficiency in the "Flea".

Carden Engine Specification

Type. - Four cylinder in line four stroke water cooled.

Cylinders. - Bore 2.5" (63.5mm), Stroke - 3.64" (92.5mm). Capacity 71.55 cub. ins. (1,172cc) Monobloc casting with detachable head and "Electron" cover plates.

Pistons - Aluminum alloy - 2 compression & 1 oil control ring

Crankshaft - Four throw carried on three main bearings, with a thrust ball race fitted behind the propeller mounting flange.

Valve gear - Standard Ford side-valve gear.

Lubrication - Full pressure feed by submerged gear pump to crankshaft main bearings and connecting rod bearings. Gudgeon pins and cylinder walls splash lubricated. Oil capacity of sump four pints.

Ignition - Dual magnetos, BTH type AG4

Carburation - Up draught carburettor, Zenith type 24U, fuel supplied by one AC mechanical diaphragm fuel pump operated by the camshaft.

Cooling - Water circulation by pump with separate header tank and radiator.

Weight - Dry no water or oil 145 lbs.

Petrol consumption - 0.53 - 0.54 pints per h.p. hour.

Performance - Normal output 32 h.p. @ 3,300 r.p.m. Maximum output 33 h.p. @ 3,500 r.p.m.

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