On Sunday July 5th, while enjoying my time at the beach, Daniel Boria, age 26, was floating over the Calgary stampede grounds carried aloft by 110 helium filled balloons while sitting in a lawn chair.
Our fascination with balloons goes back a long time, to Francisco Lana-Terzi [1631-1687] or maybe even earlier, to Giovanni Alfonso Borelli as decribed by that famous science (fiction) writer Isaac Asimov [1920-1992]:
BORELLI, Giovanni Alfonso
Italian mathematician and physiologist
Born: Naples, June 28, 1608
Died: Rome, December 31, 1679
“Borelli was a professor of mathematics and a friend of Galileo. His life, though not characterized by the controversies of his great friend, was not entirely smooth. In 1674 he had to leave Messina, the Sicilian city in which he was then teaching, and retire to Rome, where he remained under the protection of Christina, former queen of Sweden. (This was the queen whose eccentric habits had brought on the death of Descartes [1596-1650]. She abdicted in 1654 and was received into the Roman Catholic Church the following year, after which she settled in Rome.)
Borelli corrected some of Galileo’s overconservation. Galileo [1564-1642] had neglected Kepler’s [1571-1630] elliptical orbits, but now Horrocks [1618-1641] had extended them even to the moon, and Borelli rescued the ellipses, publicizing and popularizing them.
He tried to extend the vague notions of Galileo and Kepler concerning the attractive forces between the sun and the planets, but was not successful. He tried also to account for the motion of Jupiter’s satellites by postulating an attractive force for Jupiter as well as for the sun. In this he (and Horrocks also at about this time) made a tentative step in the direction of universal gravitation, but the theory had to wait a generation for Newton [1642-1726].
Borelli suggested (under pseudonym) that comets travelled in parabolic orbits, passing through the solar system once and never returning. (The parabola, like the ellipse, was first studied by Apollonius [261-190 BC]. A parabola is an open curve something like a hairpin.) Any body following a parabolic path would approach the sun from infinite space, round it, and recede forever. Such an orbit would explain the erratic behavior of comets, without completely disrupting the orderliness of the universe.
Borelli understood the principle of the balloon, pointing out that a hollow copper sphere would be buoyant when evacuated, if it were thin enough, but that it would then collapse under air pressure.
It did not occur to him that collapse could be avoided if a lighter-than-air gas were used to fill the sphere as, in essence, the Montgolfier brothers [1740-1810 and 1745-1799] were to do a century and a half later.”
—————–  Isac Asimov: Biographical Encoclopedia of Science and Technology (chronically ordered); 805 p. Avon Books, 1976
Sikorsky’s factory in Stratford Connecticut completed its first S-42 airliner/flying boat in March 1934 and Igor Sikorsky took at the earliest opportunity the mail boat to Southampton to promote his revolutionary clean looking flying machine in the Old World. His first stop was London where he delivered a glowing lecture with epidiascope projections to the Royal Aeronautical Society. His new ship was fast and it could move passengers far. In fact in the years that followed, Pan American Airways bought ten of them and used them to conquer the Pacific Ocean. The British aviation bigwigs and tech wizards listened in polite astonishment. Igor gave a glowing account of his breakthrough in the design dilemmas that had for thirty years produced only ugly-looking mechanical flying things with a multitude of wings, struts and wires.
Sikorsky had now created a roomy airplane with a single sleek small wing and four beautifully mounted engines. It carried 12 passengers with ease over 2000 miles and it could alight gently at 65 mph on the tops of the rolling waves. Its cruising speed was 160 miles per hour and Igor repeatedly pointed out how this speed in combination with the high wing load made for a comfortable ride, relatively insensitive to wind gusts and sudden vertical up and down air drafts.
IGOR I. SIKORSKY (1889-1972)
The British listened with polite amazement and suppressed skepticism. “We don’t really need speed”, said Mr. Horace Short, the builder of England’s famous double-breasted multi-wing lumbering patrol boats during the discussion afterwards.”When we need speed we’ll have Supermarine win the Schneider Cup or Messrs. de Havilland will build the Comet for winning the Melbourne race. We focus on other things.” He meant safety, a slow landing speed. And it must be said, his boats had an enviable safety record (but could not cross the ocean).
Mr. M.Langley inquired whether Mr. Sikorsky had used Imperial or US Gallons in his specifications. He apparently couldn’t believe the figures and the British ones were a good deal larger.
As to performance, Mr. W.O. Manning conceded frankly that Mr. Sikorsky had put the flying boats used by Imperial Airways completely out of date. He then proceeded to produce a global new design on the lines of the S-42 and showed its superiority.
Major R.E. Penney thought the secret of Mr. S.’s boat could be found in the enormous amount of detail work, the fairing up of the details so that the combined resistances had been reduced to an absolute minimum.
Mr. Scott-Hall mentioned in passing that albatrosses (the birds) had a large wing load but they had trouble getting themselves up in the air. And so there was a lot of back and forth talk about speed and small wings.
Until finally Major F. Green hit on the real issue: “Let’s not overlook the fact that a small wing saves a substantial amount of weight”. And here was of course the quintessence: instead of carrying wing, the airplane could now carry fuel and people. But even Igor did not seem to quite grasp the point. He came back to the subject of speed. “There is no doubt”, he stated, “that planes of great weight, capable of non-stop ocean flights, cruising between 150 to 200 miles per hour, can be designed at this time and be ready for service within two and a half to three years. Greater cruising speeds are possible, but the size of the earth does not warrant greater speeds. The progress of air transportation will benefit more if designers will give more attention to increased passenger comfort and ways and means to lower transportation costs rather than greater speed.”
Well now, would that really be possible Mr. Sikorsky? Are speed and economics independent quantities?
A cat is not a dog and a plane is not a ship.
We exchanged some polite remarks while we heaved our bags in the rack above us and sought our proper place. We just fitted in our seats together: the blonde lady in sweater and jeans at the window, I in the middle and to my right the middle aged guy in safari jacket with long hair in a ponytail… Then we underwent in silence the start of the machine and the handout of some gorgeous delicacies like peanuts wrapped in tiny little plastic bags.
After a while the plane had climbed to cruising height and I bent forward to the left to look out of the window. I saw an elegant upward turned wing tip against the hard blue expansion of the universe and the faintly curved horizon of our planet.
“Isn’t it amazing?” the lady smiled at me – “how we are sitting here crunching peanuts above the world?”
“It’s stunning,” I agreed. – “I was also observing the wing tip. There seems to be a fashion nowadays to bend them upward.”
“Well dear, it’s all about saving fuel you know. The proper shape may give you an extra 3 or 4 per cent range. It all counts with the present fuel prices.” (This conversation took place some years ago).
“How can that be?”
She explained: “The wings leave behind a corkscrew of whirling air, one at each side. It is an air vortex. In a way you may say that the airplane pulls the vortex forward. The bigger the vortex, the more energy it takes from the plane. With careful design of the wing tip the engineers try to make the generation of the vortex more gradual, less violent, see?” She looked at me and smiled.
“Yeah,” the man to my right added -“and these vortices are bloody dangerous for the little guy who is flying behind them. You better stay out of the wake of the big ones…”
And so it turned out to be a pleasant flight for all of us. The safari chap ordered a meal and offered me his dessert because he was, as he explained, a diabetic. The lady at the window knew more about airplanes than any of us. And I told them about Willy Fiedler who had built and flown a sailplane in 1933 with vertical wing tips and no fin at the tail. I even showed them a picture on my i-phone.
They were properly impressed.
We spent the rest of the flight with pleasurable chitchat. However, as always when flying, I lost my new friends at the Luggage Claim. If we had traveled by steamship we would probably still be in contact now.
DescriptionAirplane vortex edit.jpg (see earlier picture)
Date 4 May 1990 English: Wake Vortex Study at Wallops Island
The air flow from the wing of this agricultural plane is made visible by a technique that uses colored smoke rising from the ground. The swirl at the wingtip traces the aircraft’s wake vortex, which exerts a powerful influence on the flow field behind the plane. Because of wake vortex, the Federal Aviation Administration (FAA) requires aircraft to maintain set distances behind each other when they land. A joint NASA-FAA program aimed at boosting airport capacity, however, is aimed at determining conditions under which planes may fly closer together. NASA researchers are studying wake vortex with a variety of tools, from supercomputers, to wind tunnels, to actual flight tests in research aircraft. Their goal is to fully understand the phenomenon, then use that knowledge to create an automated system that could predict changing wake vortex conditions at airports. Pilots already know, for example, that they have to worry less about wake vortex in rough weather because windy conditions cause them to dissipate more rapidly.
ELEMENTARY NAVIGATION FOR AIRCRAFT PILOTS By A. W. BROWN
” A KNOWLEDGE of at least the elements of navigation is necessary to the pilots of modem aircraft undertaking long journeys. whether over land or ocean. On recognised air-routes over the land, his task will be made easier by the provision of land marks and lighthouses, but over the ocean, his only guides will be the wireless telegraph, or the SUN and stars. Wireless telgraphy provides an efficient and rapid means of locating the positions of an aircraft during a moderately long journey, but its reliability has yet to be proved over greater distances, such as will obtain in the Atlantic flight. On the other hand, observation of the sun or stars provides a reliable and never-failing means of position-finding, for it will be seldom indeed that aircraft will be unable to rise above any clouds obscuring the sky. It is not necessary for the pilot to know every detail of the methods of navigation in use on shipboard ; aircraft are in no danger from rocks or shoals, and have a large radius of vision, so that a high degree of accuracy is not essential. At the same time, the great speed of aircraft, and the extent to which they are affected by the wind, render necessary a system of navigation by which the position may be found at frequent intervals with rapidity and a minimum of calculation. “
From the same splendid Archives: FLIGHT magazine, June 19, 1919: THE FIRST NON-STOP FLIGHT ACROSS THE ATLANTIC WITH a British-designed and British-built aeroplane and engine, piloted by British officers, rests the honour of having made the first non-stop flight across the Atlantic. In an .Vickers-Vimy-Rolls-Royce biplane. [This] has won for them the Daily Mail prize of 10,000 pounds, the 2,000 guineas from the Ardath Tobacco Co., and 1.000 pounds from Mr. Lawrence R. Phillips for the first British subject to fly the Atlantic.….”
MESSAGE from Capt. Alcock and Lieut. Brown to the Royal Aero Club, sent off from the wireless station at Clifden :—
” Landed at Clifden, Ireland.at 8.40 a.m., Greenwich mean-time, June 15; Vickers-Vimy Atlantic machine, leaving Newfoundland Coast 4.28 p.m. (G.M.T.), June 14. Total time 16 hours 12 minutes. Instructions awaited.” AS SOON AS the formalities were completed Capt. Alcock and Lieut. Brown dismantled the instruments from their machine and prepared to make for London as quickly as possible.…
[after many celebrations in Ireland they finally arrived at the Royal Aero Club in London:]…
They were welcomed by Gen. Holden, who said: “…It was one of the most remarkable feats of this century, and one which would be remembered as long as the world lasted. It was nine years since Bleriot crossed the Channel, a distance of 20 miles. Everybody thought that a magnificent exploit at the time ; but here they were welcoming men who had crossed nearly 2,000 miles.”
Three cheers having been given for the airmen, there were repeated calls upon them to speak.
Captain John William Alcock (1892-1919)
CAPT. ALCOCK, standing on a chair, said :— ” I should like to thank Gen. Holden for the kind words he has said about Lieut. Brown and myself. I must say the flight has been quite straightforward. Although we had a little difficulty in keeping our course, Lieut. Brown did very well and steered a wonderful course. With regard to the flight itself all the credit is due to the machine, and particularly the engine—that is everything. If the engine went well there was nothing to prevent us getting across so long as Lieut. Brown was able to get his sights, and here we are.”
Lieut. Brown, who also was loudly cheered, [spoke in similar vein]
AFTERWARDS Capt. Alcock and Lieut. Brown stepped out on to the balcony, where they were greeted with loud cheers by the crowds still waiting outside, Lieut. Brown ultimately driving off to Ealing where a further reception by the local authorities was gone through.
Meanwhile Capt.Alcock, after dinner at the Club, went to Olympia to witness the great boxing match.
THE FOLLOWING is the story of the crossing as given to the Daily Mail by Capt. Alcock :
—” WE have had a terrible journey.The wonder is we are here at all. We scarcely saw the sun or the moon or the stars. For hours we saw none of them. The fog was very dense, and at times we had to descend to within 300 ft. of the sea.For four hours the machine was covered in a sheet of ice carried by frozen sleet; at another time the fog was so dense that my speed indicator did not work, and for a few seconds it was very alarming. We looped the loop, I do believe, and did a very steep spiral. We did some very comic “stunts,” for I have had no sense of horizon. The winds were favourable all the way : north-west and at times south-west. We said in Newfoundland we would do the trip in 6 hours, but we never thought we should. An hour and a half before we saw land we had no certain idea where we were, but we believed we were at Galway or thereabouts. Our delight in seeing Eashal Island and Turbot Island (5 miles west of Clifden) was great. People did not know who we were when we landed, and thought we were scouts on the look-out for the ‘ Vimy.’
“We encountered no unforeseen conditions. We did not suffer from cold or exhaustion except when looking over the side ; then the sleet chewed bits out of our faces. We drank coffee and ale and ate sandwiches and chocolate. The only thing that upset me was to see the machine at the end get damaged. From above, the bog looked like a lovely field, but the machine sank into it up to the axle and fell over on to her nose.”
It certainly was unfortunate that what looked like a good meadow from above should have turned out to be a bog. Not only did the ” Vimy ” bury her nose in it but a R.A.F.machine which flew over from Oranmore to render assistance also came to grief. Later advices indicate that the Vickers machine is not so seriously injured as was at first supposed.
DURING the greater part of the flight of 1,950 miles the machine was at an average altitude of 4,000 ft. but at one
time—about 6 a.m.—in an endeavour to get above the clouds and fog, it went up to 11,000 ft. Lieut. Brown was only
able to take three readings for position, one from the sun, one from the moon and one from the Pole Star and Vega.
On passing Signal Hill, Lieut. Brown set out a course for the ocean on 124 deg. compass course and at 3 a.m. from an observation on Polaris and Vega he found he was about 2 deg. south. He then set a course of 110 deg.
Between 4 and 5 a.m. the machine ran into a very thick fog bank, and the air speed indicator jammed, through sleet freezing on it, at 90 m.p.h. It was then that Capt. Alcock thinks the machine looped, at any rate it went into a steep spiral which only ended with the machine practically on its back about 50 ft. from the water. The machine was covered with ice, and it continually became necessary to chip ice off the instruments, etc. Capt. Alcock says that he nursed the engines all the way, and had one-third of his petrol supply left when he landed. One of the exhaust pipes blew off, but otherwise there was no trouble from the engine installation.
APPARENTLY the start from St. John’s provided an anxious time for the onlookers. The machine had a hard job to get away with her heavy load. The aerodrome level was only 500 yards long, but the machine took off at 300 yards, and just managed to clear the trees and houses. However she climbed steadily if very slowly, and when she passed over the harbour a t St. John’s had reached a height of 1,000 ft.
THE FLIGHT has shown that the Atlantic flight is practicable, but I think it should be done not with an aeroplane or seaplane, but with a flying-boat. We had plenty of reserve fuel left, using only two-thirds of our supply.”
From FLIGHT Magazine, Deceember 25, 1919: THE DEATH OF SIR JOHN ALCOCK IT is with most profound regret that we have to record the fatal accident to Sir John Alcock, which occurred on the afternoon of December 18,’ while he was engaged in taking a new Vickers machine to Paris in connection with the Salon. It appears that the machine when nearing Rouen had great difficulty in negotiating a strong wind. A farmer at Cote d’Evrard, about 25 miles north of Rouen, saw the machine come out of the fog, commence to fly unsteadily, and—it was then about 1 o’clock—it suddenly crashed to the ground.
SIR JOHN ALCOCK was taken from the wreck, but unfortunately there was considerable delay in getting medical assistance as the farmhouse near where the crash occurred is out of the way. As soon as the accident was reported, doctors rushed from No. 6 British General Hospital, Rouen, but they were too late. It is probable that an enquiry will be held by the French authorities, at which the Air Ministry and Messrs. Vickers will be represented. Arrangements are being made for the conveyance of the body of Sir John Alcock to England for burial in Manchester, his native city. The death of Sir John Alcock is an irreparable loss to aviation. His great flight across the Atlantic is too fresh in the mind of readers of FLIGHT for further reference to be made to it here, while his previous work is recorded in the pages of past volumes of this paper.
NOTE: After his record Atlantic flight, Sir Arthur Whitten Brown pursued a career in industry. He rejoined the RAF for a short period during the Second World War, but had to resign because of ill health. He died in his sleep in 1948.
When, in 1953, in my capacity of apprentice in the KLM Maintenance Service at Schiphol, I started one morning to help take off half the wing of a Douglas DC-3, I was most astonished to find that the wing of this rather famous and historic airliner had no sturdy spar in its innards, but that the metal wing cover had a seam from front to back at a position close to the engine, where it was simply bolted to the center section of the airplane.
Only recently I read that this particular construction was called ‘multi-spar’ and invented by Jack Northrop around 1930. In document 3-22(a-b) 3-22-b: Engineering Department, Douglas Aircraft Co. “Development of the Douglas Transport”, Technical Data Report SW-157A, ca. 1933-34, Folder AD-761184-05, Aircraft Technical Files, National Air and Space Museum, Washington, D.C., one can find:
“In the Douglas and Northrop types of multi-cellular wing construction, there are a multiplicity of full length span-wise stiffeners, and the fact that they have no abrupt changes or ‘breaks’ [in their extended shape] results in no concentration of stresses. With the centroids of the stiffeners located at the maximum distances from the neutral axis of the [wing] section, a most efficient structure for absorbing the bending load is obtained.”
In my interpretation this means that the outside skin of the wing (well reinforced with span-wise stiffeners) will absorb all the bending stresses and that one can dispense with heavy spars directly connected to the fuselage. The remainder of the text is too interesting to be omitted, as we, modern airline customers, only too well know how scary modern airliners sometimes flex their wings:
“In a highly stressed airplane, torsional rigidity of the wing is of paramount importance in the prevention of wing flutter at high speeds and torsional deflection of the structure must therefore be kept to an absolute minimum. When under load, there will always be some vertical deflection but this must not be excessive since a wing with large vertical deflections might cause jamming of aileron controls and by no means inspires confidence in the passengers or pilots.”
Also, vibrations can generate most annoying noise (I remember flying in the Vickers Vanguard in 1962):
“If unsupported flat metal surfaces are even moderately large, there is always a tendency for the middle of the surface to vibrate in flight, even when there is no stress. This is termed ‘oil canning’and will, in time, cause fatigue in the sheet metal and in the rivets and cause rivet heads to work and to pop off. These unsupported flat surfaces continually drum and cause a noise that cannot be completely eliminated in a cabin, because part is carried as vibration thru the structure. This is different from ‘wrinkling’of the skin. Wrinkling will be present in every metal wing with a flat metal covering taking stress. These wrinkles are deflections of the skin under load and ordinarily do not have any tendency to vibrate.”
The report continues with more on the subject of the wing design for the early Douglas airliners:
“In determining the wing construction of the early Douglas machines single, two, three and multi spar designs were considered as well as shell type and multi-cellular designs. After a thorough investigation of all types the Northrop multi-cellular wing construction was finally decided upon. This type of structure consists of a flat skin reinforced by numerous longitudinals and ribs. The bending is taken by the combination of flat skin and full length [longitudinal] stringers. Three main flat [vertical] sheets or ‘webs’ carry the shear loads. Torsion and indirect stress are carried by the skin with frequent ribs preserving the contour and dividing the structure up into a number of small rigid boxes or cells. Since the major loads are carried in the outer surface of the wing as well as in the in the internal structure, an inspection of the exterior gives a ready indication of the structural condition. The unit stresses in the material are low and therefore the deflections are at a minimum giving a maximum in rigidity. This construction has proven to be a happy medium of those considered since it combines practically all of the advantages of each; namely, very small unsupported areas, extreme lightness for its strength and rigidity; also ease of construction, inspection, maintenance and repair.“
For the early Douglas airliners:
“The Northrop wing being comparatively small, it is economical to have many of the stringers run from the top to the bottom of the wing as shear webs or spars. However, when the principle is carried out on a larger scale, as in the DC-1 with its deeper wing, it is more efficient to have only three shear webs or spars. Thus it was not necessary to evolve a new type of structure but merely to adapt a time proven type to the dimensions of the DC-1.” [end of quote]
The exterior wing was fastened to the center section with a great numbers of bolts. It was my task to receive each bolt, nut and washer that became undone and secure them in a numbered hole in a plywood board. In the end there were 20 boards with a total of 652 bolt sets. My mentors /colleagues worked according to strict KLM protocol [see the following drawing which I owe to Mr. Wim Snieder, The Hague, Holland] and had the use of an overhead crane.
We finished unbolting the [half] wing by 3 pm and went for tea, delivering on our way the boards with fasteners at Testing for examination on hair cracks and corrosion.
airplane construction interbellum – like Rohrbach and many other pioneers