Monday, May 10, 2010
FLYING THE D.H. 88 COMET RACER
THE DH-88 COMET ONE OF MY FAVORITE OF ALL AIRCRAFT.. BELOW ARE A FEW STORIES ABOUT THE COMET AND HOW TO FLY IT.
A. E. CLOUSTON
NAVIGATING the D.H. Comet across the world is a step outside the normal run of flying. Yet, provided you stick to three or four hard-and-fast rules it is no superman's job.
I would not consider taking it on without the set of instruments we took to New Zealand and back. I must have two big, plain-faced P.4 compasses aboard, well swung
and tested. The cardinal secret of Comet navigating is never to deviate by a degree from your
compass course.I always keep my Sperry directional gyro set at o. When you get tired
after hours of blind flying the markings in degrees on the gyro become a bit blurred and impossible to keep a course on. The big, round o requires
much less concentration. The particular Sperry we had in Australian Anniversary was the best one I've ever flown on On the New Zealand trip it sometimes went two hours without resetting. Besides the directional we carried two lateral Sperrys, all three being
driven off the port engine vacuum pump. For safety, in addition, we had a Reid and Sigrist turn-and-bank indicator driven off an external venturi. There is safety in numbers. In the Comet, in really blind conditions, iced-up instruments mean jumping out. I fly with two good watches on my wrists and an aircraft clock in the dash. One watch and the clock are set to G.M.T., and all navigation is timed on them. The other watch is set to local time, wherever I am. The general scale of our maps was 16 miles to the inch, sometimes 63 miles to the inch, and across Australia and over the Tasman Sea my map and charts were scaled down to about 150 miles to the inch. Now for nagivation itself. Working out the course from A to B, I take the direct bearing and mean variation, and set that course off on the compass. I have never yet allowed for wind drift in the Comet, not even when I have known there to be a strong cross-wind blowing. It has been my experience that meteorological reports of weather for
2,000-mile stretches at 7,000ft.—the Comet's operating height—cannot be trusted. The upper winds have always turned out to be different from the way they should have been. It was in the Johannesburg Race, 1936, that I discovered drift can be ignored in machines that cruise at
around the 200 m.p.h. mark over several thousand miles. In twelve hours' flying cross-winds will practically always cancel themselves out. When Ricketts and I started away on our first unfortunate crack at the New Zealand trip in February we found ourselves at one point over Europe 40 miles north of our course. We just kept to our compass course, and three hours later, after blind flying, we were 30 miles south of it. I never correct such flying for drift—I wait for the correcting wind to turn up a little farther on. Whenever possible, I check up my position on definite landmarks like rivers, mountains and islands, and keep marking my position on my maps. At night, unless there is a strong moon, there is scarcely anything to be seen.
Over 2,000 miles probably half of the course is under cloud. And, in any case, crossing a country like India by night brings up very little indeed to check your position on. Through the
dark hours I just sit on my compass course, speed, height and time. I try whenever possible to schedule my refuelling stop for daylight. It is madness to go off for ten hours' flying
and then expect to find an aerodrome in the middle of a strange country like Australia, Africa or India in the dark. One should be able to owe accuracy in navigating to one's own confidence in course-keeping. Sometimes I have wanted to think my compass was out 20 or 30 degrees when mountains, or snow peaks, or islands sticking out of the sea have given me a cross-bearing a bit different from that which I had expected. But in every case I have stuck to my original course, and the good old P.4 has turned out_ to be right. I would trust a properly swung and adjusted
compass for a month. When I get a definite check by landmark (confirmed by a second check) I work out ground speed and keep on working it out. I keep applying the result of my little arithmetical sums to the distance still to go. Flying up to 1,61.0 miles across open sea, as we did to New Zealand, we found that wind direction as shown by sea spray was frequently entirely different at our 7,000ft. We always kept to that height, no matter what storms lay in front. I only fly round cloud patches over land, and when I am fairly certain of where I am. If you begin to make five-mile detours over the sea your landfall after 1,000 miles may be very different from the one neatly drawn on your map. We had one or two tastes of ice formation, the worst over the 1,000-mile desert stretch between Cairo and Basra. In just over three minutes one thick, heavy bunch of cumulus clouds over this stretch ruined the aerodynamical qualities of the Comet, loading us with two to three inches of ice on the wings and tail. The pitot head was frozen up, and the only instruments that continued to function were the Sperrys. When thus flying blind and
iced-up, it calls for considerable concentration to keep level with no air-speed indicator to help.
In severe tropical storms and bumps at 200 m.p.h. blind flying instruments in the Comet are only just readable. Crossing the Timor Sea we were compelled, Sutton--harnessed as we were, to shield our heads from the roof with air cushions. Then at Charleville, Central Australia, two of the Qantas pilots told us they liked the Timor because there were no
bumps to worry them there! Fortunate mortals, they fly with radio, and can, and do,
detour twenty miles to get round a bumpy area, while poor record-breakers, if they
would make their proper landfall, must plough straight ahead and take whatever's
coming to them. Landing the Comet is a matter to be dealt with in sequence. I like to arrive over my aerodrome and make four or five circuits before I land. It is not an easy aeroplane to see out of, and I like to have everything under control and observation.
First the engines are cut down to about one-third throttle, dropping speed down from 200 to about 130 m.p.h. Then the undercarriage is wound down. It takes 141 turns of the hand wheel to get the undercart extended, and the wheel can only be turned about a tenth of a revolution with each movement. It takes four or five minutes to do the job calmly and efficiently. Next the airscrews are put into fine pitch, speed cut down again to n o m.p.h. and the flaps brought on. They are intensely stiff, and take just about all your strength to bring down. Then round to land in a very wide approach turn with throttle is half open. I take her.
Both pilots wore Irvin seat - pack - type parachutes. There is a small luggage space behind the rear seat. The main fuel tanks (128 and no gallons; are in front of the pilot, and there is a 20 gallon tank aft. round to have at least a mile in which to fly in to land at hot, sandy aerodromes. It is my opinion that one should on no account try to put the Comet down in a pretty three-point landing. It is the only aeroplane I know that must NOT be landed that way. It must always be a slightly " wheel " landing. If a three-pointer is tried, the Comet won't sit down on three points; she will just balloon off into space again.
Landing is not easy, but taking-off fully laden from tropical aerodromes is a major problem. The machine is excessively tail heavy and very prone to swing. If it develops a good swing you catch it early with the motors and, if need be, the brakes as well. The fact that you can see nothing ahead adds to the difficulties. The engines are opened to half-throttle to allow them to start turning evenly and get the machine rolling nicely, and then increased to wide open. Partial swings can be corrected, if you catch them in time, by juggling the throttles only. The brake lever is left a quarter on. The brakes themselves are not working in this position unless the rudder bar is brought into play, when they work as another check on swing. The tail will show no sign of coming up for two or three
hundred yards, as full-load acceleration is so slow. But once the tail is lifted the Comet, as clean as a knife, has An unorthodox snapshot of Clouston and Ricketts, amusingly suggestive of the famous painting, "The Death of Nelson." They are watching the Comet being prepared in the works of Essex Aero Ltd., at Gravesend. acceleration of a positively amazing order if it is held in flying position.
In spite of the apparent speed, it has to be held down the full length of the runway. If you try to lift it off before it is ready it will simply sit back again on its tail and slither—
on into the hedge. There is no normal sensation that you are about to fly as the Comet approaches the boundary. You must allow it to run and run until just before the hedge, when the stick is eased back. Then it will have attained about 90-95 m.p.h., and will fly off soggily! After the first upward climb it must be eased down slightly, and the airscrews put into coarse pitch after the undercarriage has passed the
half-up position during retraction. And so up to 7,000 feet in a long, gentle climb at 140 m.p.h. on the clock. Probably our most moving take-off was from Charleville, homeward bound. We had tanked up to 200 gallons for the hop across 1,700 miles of featureless Australian desert to Darwin, when closer inspection by car of the 830-yard runway caused me to order 40 gallons to be pumped out
again. ] Normally I must have 1,000 yards for safety, and in tropical heat something like 1,700 yards. With the 40 gallons removed • we just cleared the hedge, after one second's suspense when the machine sank a few feet after being pulled off in the last five yards of available space.
" It was in the Johannesburg Race, 1936, that I discovered drift can be ignored in machines that cruise at around the 200 m.p.h. mark over several thousand miles.'' " One should be able to owe accuracy in
navigating to one's own confidence in coursekeeping. . . . I would trust a properly
swung and adjusted compass for a month," " It is my opinion that one should on no account try to put the Comet down in a pretty three-point landing. It is the only aeroplane I know that must not be landed
that way. ' " We had one or two tastes of ice formation . . . In just over three minutes one thick,
heavy bunch of cumulus clouds . . . ruined the aerodynamical qualities of the Comet, loading us with two or three inches of ice on wings and tail. "
IF, as they say, long-distance record-breaking is dead, the
D.H. Comet's latest effort seems to prove that it won't
lie down. Messrs. Clouston and Ricketls, indeed, have
made it sit bolt upright.
In the process of travelling from England to New Zealand
and back, 26,500 miles, in three hours less than eleven days
(a steamer would take 80), they have established ten " records."
official and/or unofficial. Their flight :
Is the first direct round air trip to N.Z. and back.
Beats Miss Batten's (Gull) England-N.Z. time of n
days, 1 hr. 25 min. (October, 1937).
Beats Miss Batten's 5 days, 13 hr. 15 min. homeward
time from Port Darwin to England (October, 1937).
Breaks the record set up in the Comet in 1934 by
C. W. A. Scott and the late T. Campbell Black for the
return trip from Australia, though net their outward figure
(2 days, 4 hr. ^^ min., London-Melbourne), in the Mac-
Cuts three days off the Australia-and-back time of 13!
days by Cathcart Jones and Ken Waller (Comet) in 1934.
Break:. The records England-Sydney, Port Darwin-
Sydney, and Sydney-New Zealand
It is, of course, hardly fair to make comparisons with Miss
Batten's records, achieved solo in a single-engined machine.
Actually, four of the new figures will, it is hoped, be recognizable
by the F.A.I, as coming in the capital-to-capital category:
London-Sydney, 80 hr. 56 min.
London-Blenheim (N.Z.), 104 hr. 20 min.
Blenheim-London, 140 hr. 27 min.
Sydney-London, n o hr. 22 min.
It is thought likely that the F.A.I, will be prepared to recognize
any aerodrome in New Zealand as a capital for such purposes.
Blenheim—where F/O. Closton's family resides—is
at the northern end of the South Island.
Out and Home
The story of the outward journey was told last week. After
an abortive attempt a few weeks earlier, which ended in
Turkey with a damaged undercarriage, F/O. A. E. Clouston,
with Mr. Victor Ricketts as co-pilot, took the four-year-old
Comet off from Gravesend at 8.17 p.m. on Tuesday, March 15.
He put it down at Blenheim 4.57 a.m. on Sunday, March 20.
At 10.2 a.m. G.M.T. the next day the machine was in the
air again on its return trip. Sydney was reached at 4 p.m.
(another Tasman record). At 3^39 a.m. on the Tuesday they
left for Darwin reaching there at 2.-59 pm. They took off
for Surabaya (Java) at 1.32 p.m. and left Singapore at 5.47
p.m. next day, Wednesday. Karachi was reached, via Calcutta
and Allahabad, at 1.42 a.m. on Friday. They left at
2.58 a.m. for Basra, which was attained that ‘afternoon, while
the opening ceremony at the new airport was in progress
They were off again at 10 p.m. on their final and hardest
stretch—3,200 miles in 19 hours, with only very brief refueling
stops at Cairo and Marseilles, and no food or sleep. Croydon
was thankfully reached at 5.40 p.m. 011 Saturday. Set down thus in bare figures, that it may be kept on record, the story of the
flight sounds, perhaps, prosaic. But against this background may be pictured
the actual sensations of» the two men who made it; the ten-hour 2,000-mIle
stretches, sometimes protracted to 12 hours by head winds ; the incessant roar,
scream and bumping in the cramped tandem cockpit; the desire for sleep ; the
anxieties of taking-off from small aeiodromes in "thin" tropical air v.ith
nearly a ton of petrol; fog, cloud and thunderstorms, all of which were encountered.
These things considered, one may marvel at the enthusiasm of people
who will do them—and it so happens that quite " un commercial " enthusiasm has
played a large share in the present flight.
The D.H. Comet, before rebuilding by Essex Aero, Ltd., for the Damascus
Race had Gipsy Six R. engines; it now has Gipsy Six Series II
engines with D.H. v.p. airscrews. The machine is mainly of
"wooden stressed-skin" construction, with metal fairings.
The equipment for the flight included : Instruments by .Sperry, Smiths. Short and Mason, Reid and Sigrist.and Record Electrical Company. Instrument panel by Essex Aero. Ltd.
Controls by M.H.C.. Ltd. Switches, lighting, etc., by Eotax. Harley
lauding light. Accumulator by Dagenite.
Aircraft Components' undercarriage. Tyres and wheels hy Dimlop.
Brakes by Bcndix. Steel tubing by Accles and Pollock. Timber by the
I/oudon Plywood and Timber Co. Aluminium by the British Aluminium
Co. Elektron by ¥. A. Hughes and Co. Kxhaust manifold material hy
Henry Wiggin and Co. Finish by Cellon. Safety glass by Triplex and
Splintex. Rhodoid roofing. Irvin parachutes. Sloseley air bags.
Gipsy-Six Series II engine with D.H. v.p. airscrews. Superfiexit oil
piping. Sparkina plugs by K.L.G. Claudel-llobson earburation. Wellworthy
piston rings. Magnetos by Euston Ignition Co. Oil organisation
by Wakefieid. Fuel organisation by Anglo-American Oil Co. and their
associated companies abroad. Preparation of machine by Essex Aero,
Ltd. Flight sponsored by Sydney Daily Telegraph
FOLLOWING so magnificent a flight as that achieved by F/O A. E. Clouston and Mrs. Kirby-Green in the De Havilland Comet it is difficult to know which
To praise first, the skill and endurance of the pilots Or the faultless behavior of t h e aero plane and engines. Though recognizing that the figures should not be
"officially" compared, it is interesting to observe that the out-and-home journey to the Cape, taking 5 days 17 hours 28 minutes from Croydon to Croydon, did not merely clip a matter of hours off the existing record set up by Mr. H. L.
Brook, but no less than 3 days 16 hours 2 minutes. On the outward trip, as reported fully in Flight last week, the Comet, now called The Burberry, set up a new record of 45 hours 2 minutes, this being 1 day 9 hours 24 minutes better than
Miss Amy Johnson's time. Then, on the return journey, a
record time of 57 hours 23 minutes was achieved, 1 day 14 hours 57 minutes better than Mr. H. L. Brook's figure. Large sections of the flight were made by night, and praise is due for the very great navigating skill displayed. Landings
were made using only the large Harley light in the Comet's nose, aided in some cases by the moon. On the return journey the pilots were showing signs of
fatigue, although they experienced better weather. Some of the high-altitude aerodromes in Central and South Africa had made take-off with big loads of fuel more difficult, and at Cairo the Comet was put down only on the third attempt,
owing, it is understood, to dazzle from the instrument panel lights.
The arrival at Croydon at 3.23 on the afternoon of Saturday, November 20, was triumphal if not so rowdy as on previous occasions. A large force of police and a long wait in the cold had thinned the crowd to a safe number of friends and
A short history of the Comet's previous successes appeared in Flight last week. Since the Istres-Paris-Damascus race in August the very full wireless equipment (including generator and converter) has been removed, giving a weight saving of
In its original form the Comet had two Gipsy Six R engines, but for these were recently substituted two Standard Gipsy Six Series II engines with 1,000-size D.H. v.p. airscrews. The use of v.p. airscrews is almost essential on a machine combining
speed and range. The all-up weight in this case is increased by about 1,000 lb., which means an added 1,300 miles in range, while the cruising speed is improved by 12per cent,roughly the difference between 190 and 210 m.p.h.
THERE and BACK
The Fine Croydon-Cape-Croydon Flight of FO. Clouston and Mrs. Kirby-Green
in the D.H. Comet : 14,700 Miles at 189 m.p.h. Average
The fuel capacity is a little more than in the original form—
123 + 108 + 25 gallons, with an additional 8 making 264—sufficient
for 13 hours or 2,800 miles.
When the Series I engines were fitted, under the direction of
?ir. R. J. Cross, of Essex Aero, Ltd., a modification of the
cowlings was necessary to suit the spinners of the 1,000 hp
v.p. airscrews. Other modifications include an additional
Vickers' fuel tank vent in the cockpit where i t could not ice up
as in the Damascus race, and strengthened shock-absorber
units to stand up to the increased loading. The extra vent
proved essential on certain sections of the trip when ice formed
very quickly and the engines showed signs of getting starved.
Six thermos flasks for beef tea, brandy and milk, etc., and
Moseley " non-surging " cushions added comfort to the trip,
and a little room in the nose for a change of clothes, food,
spares and papers was greatly appreciated.
During the whole flight there were only two slight mishaps.
On the outward journey a delay of 7 hours occurred, due to
trouble in getting permission to take off, and on the return
a delay of 8 | hours occurred at Broken Hill while small adjustments
were made and further "permissions" were obtained.
Flying Officer Clouston specially praised the Wakefield
Organization, which gave valuable aid on the flight. Among
the detailed items of, equipment which played their part in
securing the success were:—
The D.H. Comet: Smith's air-speed indicator, altimeter and oil pressure.
temperature, boost and petrol pump gauges, rev. counters and tach ; Reid and
Sigrist turn and bank indicator; Sperry artificial horizon and directional gyro;
Kollsman sensitive altimeter; Weston intake thermo-couples and oil temperature
gauges ; Short and Mason and Husun compasses ; Harlev landing lights ; lelcta
M.K.C. controls; Dagenite batteries (Peto and Radford); Super Bexit oil pipinn:
Petroflex petrol piping ; Vickers petrol cock ; Dunlop tyres; Berulix brakes;
Cellon finish ; British Aluminium tanks and cowlings; RenokU and Aeries and
Pollock steel tubing ; Rumbold upholstery ; small parts by Brown Bros. (Aircraft)
Air Materials and Mosers ; Skef ko ball races for undercarriage ; Hoffman ball races
for controls. ..
The D.H. Gipsy Six Engine* : D.H. v.p. airscrews; High Duty Alloys and Sterlme
Metals piston forgings ; Motor Components valves ; Sterling Metals bieKtron
castings for rocker boxes and crankcases ; Mills alloy cylinder heads; Sailers
valve springs ; English Steel Corporation crankshaft; Hoy't white metal bearings.
Eyre Smelting Company's steel-backed bearings; High Duty Alloys connecting
rods; B.T.H. magnetos, K.L.G. bottom-seating plugs; Hobson carburetor,.
Auto lean filter; Rotx starter; British Insulated Cables and B.T.H. camps.
Coopers and Hall and Hall gaskets; Wellworthy piston rings; Rotax vacuran
pump ; Amal flame trap and fuel pump ; Pinchiu Johnson paint; Simms con,
lings ; Esso fuel ; Wakefield Castrol oil.