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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