2015: ATERRISSAGE – HAPPY LANDING

Hold fast to dreams For if dreams die Life is a broken-winged bird That cannot fly. Hold fast to dreams For when dreams go Life is a barren field Frozen with snow. Langston Hughes
Huntington Beach,  California

The Ocean,

the beginning and the end.

479px-Maxwell_B-24
Consolidated B-24 Liberator

I wonder who will be coming to pick us up.

This big boy from San Diego?

It has a wonderful wing.  Its hull is from a flying boat.

It can’t land here. Just casing the place, I suppose.

Flugzeug Blohm & Voß BV 238 V1
Blohm & Voss BV-238 (100 tons)

The biggest one built in Germany, in Bremen, during the war.  It might be able to land here.

Rumor had it that Der Führer was planning to escape with it to Argentina.

I bet its designer, Dr. Vogt, never thought he would end up close by here, in Santa Barbara.

Martin M130
Glenn-Martin M-130 Clipper

The best one ever built.
It conquered  the Pacific

Latecoere 521 Flying Boat12A

As Boeing knows: never underestimate the French

H-4_Hercules_2
Hughes / Kaiser HK-1 Spruce Goose

This one is retired now in Oregon.

Pity it never really flew.

400px-Australian_pelican_in_flight

This one still flies.

May it outlive us all.

Au Revoir!

Ω

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1934: A PLANE IS NOT A SHIP

Revolutionary Sikorsky S-42 (1934)
Revolutionary Sikorsky S-42 (1934)

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.

Ugly Short S-14 Sarafand (1932)
Ugly Short S-14 Sarafand (1932)

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)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.

Phoebastria_albatrus (picture: Wiki)
Phoebastria_albatrus (picture: Wiki)

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.

for the full text of Igor Sikorsky’s lecture, click:  https://ritstaalman.files.wordpress.com/2014/12/sikorskya.pdf
see also Part III of Early Atlantic Airliners:  ATLAIRpart3
for books on the conquest of the Atlantic by air: http://www.Lindbergh-aviation.de atta12e9

1933: High Fashion in Wings

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.

picture by Monica Staalman
picture by Monica Staalman

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.

this magnificent picture is from NASA, via Wiki. See note below
this magnificent picture is from NASA, via Wiki. See note below

“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.

1933: Aka Flug Stuttgart F-1 Fledermaus, design Willy Fiedler

1933: Aka Flug Stuttgart F-1 Fledermaus, design Willy Fiedler

See also:

https://earlyflightera.com/from-fledermaus-to-polaris/

http://en.wikipedia.org/wiki/Wingtip_device

http://en.wikipedia.org/wiki/Wake_turbulence where you will find:

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.

1919: ELEMENTARY NAVIGATION FOR AIRCRAFT PILOTS

June 1919 Crowd awaiting departure of Alcock and Brown from St John's NFL
June 1919 Crowd awaiting departure of Alcock and Brown from St John’s Newfoundland  (source Wiki)

Found in the unsurpassed archives of FLIGHT magazine April 17 1919:    (http://www.flightglobal.com/pdfarchive/index.html)

  • 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. “

  • Captain Brown
    Lieutenant A.W. Brown (1885-1948)
  • 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 William Alcock 1892-1919

    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.

    Vickers Vimy at the ready in St John’s Newfoundland, June 1919

    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.’

    HOWEVER:
    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.”

    800px-Alcock-Brown-Clifden1
    Alcock and Brown: landing in a marsh at Clifden, Ireland

    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.

    The Start from St John's
    The Start from St John’s, Newfoundland

    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.”

  • 773px-Salon_de_locomotion_aerienne_1909_Grand_Palais_Paris
    First “Salon_de_Locomotion_Aerienne”_1909_Grand_Palais_Paris
  • 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.
  • [picture credits:  http://commons.wikimedia.org/wiki/Main_Page]

1930’s: LIGHT METAL WINGS II

1890: the Wing Otto Lilienthal used
ca 1890: the Organic Wing Otto Lilienthal used

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.”

Northrop N9MB as seen at the Air Museum Planes of Fame in Chino Ca, where it is flown regularly.
Northrop N9MB Flying Wing as seen at the Air Museum Planes of Fame in Chino Ca, where it is flown regularly.

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.”

Northrop wing with skin removed showing longitudinal stringers [from: WoodToMetal.pdf  SI 94-7718]
Northrop wing with skin removed showing longitudinal stringers [from: WoodToMetal.pdf SI 94-7718]
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.“

Douglas DC-3
Douglas DC-3

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]

Detachable wing of DC-3
Detachable wing of DC-3

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.

Part of the KLM protocol for dis-assembling wing of Douglas DC-3
Part of the KLM protocol for dis-assembling wing of Douglas DC-3


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.

http://www.airnieuws.nl/phregister/476/luchtvaartnieuws.html
http://www.airnieuws.nl/phregister/476/luchtvaartnieuws.html

1930’s: LIGHT METAL WINGS I

main spar box Boeing
picture source: navyaviation.tpub.com

“…The ability of sheet metal to carry an increasing load after it had begun to buckle – which in conventional structures was regarded as failure – was crucial to the development of metal airplanes. It had first been discovered in 1925 by Dr.Herbert Wagner, who was then working for the Rohrbach Metall-Flugzeugbau in Berlin, Germany, but his findings were not published until 1928 in English by NACA. Northrop’s work was done independantly. Wagner went further than Northrop in his analysis of the way in which a thin sheet of metal behaves when supported at the edges, as it is in airplane structures, and he evolved the theory of the diagonal-tension field beam to explain it. This theory, and elaborations of it, formed the basis for the development of a/c structures from the mid 1930’s onward. But it was not applied to the early Northrop airplanes or the Douglas DC-1-2-3. Northrop’s construction gave a good enough ratio of strength to weight for these airplanes, and the use of Wagner’s theory would have added to the complication and cost of design…”

The above quotation is from: Ronald E.Miller; David Sawers, “The Technical Development of Modern Aviation” (Routledge & Kegan Paul: London; 1968) p.65
In August 1933 Paul Kuhn  wrote an explanation of Wagner’s theory as NACA Technical Note No. 469 “A Summary of Design Formulas for Beams Having Thin Webs in Diagonal Tension”,  Langley Memorial Aernautical Laboratory. Washington,. A copy of this paper may be downloaded from the Herbert Wagner page on this website.

1890: THE TIN AIRSHIP

SCHWARZ, David
Born: Zalaegerszeg, Hungary, 20 December 1850
Died: Vienna, Austria, 13 January 1897
Timber merchant; airship designer
SCHWARZ, Melanie: his wife and business partner
SCHWARZ, Vera, their daughter; opera singer

SchwarzAirship FotoHungary

A tin airship was brought to flight by David and Melanie Schwarz from Agram, Dalmatia (now Zagreb, Croatia). At the end of the nineteenth century, it was they who built the first metal airship in the world. The story is well documented by now (see links below) but remains remarkable because they were the predecessors of Graf von Zeppelin, who is generally assumed to have been the first to build the historic metal steerable, lighter-than-air vehicles that now carry his name.
It is also remarkable because here a woman played a decisive role in the construction of a flying machine. (In the first half century of aviation history there have been a good number of courageous and successful female pilots, I know, however, of no other example of a woman who was involved in the business of building a flying machine, nor have I ever heard of major contributions in this field by ladies such as Mme Blériot, Mrs. Boeing or Frau Heinkel…)
scaled-209x400-David-Schwarz-und-Frauy

The husband, David, was a man of some importance, a timber merchant who every year spent long months in the forest, overseeing logging operations. His desire was for a magical, mighty machine that would be able to lift the cumbersome trunks of trees straight up and out of the hilly terrain. His thoughts materialized into the design of a rather large metal cylinder, filled with hydrogen gas. The pressure inside the vessel would equal the outside air, so as to avoid extreme forces on the shell. In order to be able to levitate, the total construction, plus its load, would have to be lighter than the air it displaced, according to the Law of Archimedes.
Being an avid reader of technical books, he had learned of the miraculous metal aluminium (or aluminum in English speaking countries), known since 1825 as silver-from-clay. As Wikipedia states: “Aluminium is the third most abundant element (after oxygen and silicon), and the most abundant metal in the Earth’s crust.” Yet it proved extremely hard to extract from its host, the ore bauxite. Indeed, the first small quantities produced were so costly that they were used only for art objects and expensive cutlery at the court of Napoleon III.

404px-Eros-piccadilly-circusX
Aluminium Eros at Piccadilly Circus London, ca. 1895

Production on an indutrial scale had to wait until in 1886, when Charles Martin Hall in Ohio, USA, and Paul Héroult in France invented the electrolytic process of refining aluminium at practically the same time, using an electro-oven.
       This development was only possible after the perfection by
George Westinghouse (and predecessors) of the electrical transformer, a device that could deliver to the oven extremely large currents at low voltage. The oven required a vast amount of electric power, which had become available on an industrial scale after Man had learned how to build hydro-electric power stations (for instance at Niagara Falls, 1895 and Neuhausen Switzerland, 1888). The production of relatively cheap aluminum became from then on feasible and Schwarz’s dream came into the realm of reality.
It goes without saying that in order to become truly dirigible, his tin cylinder would also need a motor with propeller and rudder (although for lifting tree trunks out of the woods a cable balloon might have served the purpose). The practical, portable combustion engine was put on the market around 1885 by Gottlieb Daimler and Carl Benz.
Summing up, we may say that the light-weight metal steerable airship could not have been built before 1890 and that Schwarz’s invention represented the cutting edge of technology.
Schwarz first approached the Austria-Hungary War Ministry, but received little interest in his ideas. He found more resonance in Russia and a first attempt by him to build a metal airship was made in St.Petersburg. When these attempts failed Schwarz returned to Zagreb.

Zagreb Trg1880

In 1894 he got involved with the German entrepreneur Carl Berg from Ludenscheid, Westfalen. Carl’s firm specialized in the production of aluminum flat sheet and rolled shapes with various profiles. The factory obtained raw metal from the first European aluminium smelter in Neuhausen, Switzerland (1888), later known as Alusuisse. Berg saw great potential in Schwarz’s project and decided to help him transform ideas into hard reality. In fact, it was Berg’s engineers who made the definitive calculations and ultimate design for the airship. On paper it looked sort of like a giant spray can lying on its side: a cylinder with a flat bottom and a conical point. An open gondola hanging from the cylinder would hold the pilot, the Daimler engine (16 hp) and the steering controls. Via belts the engine drove no less than four propellers, one of them a horizontal one to aid levitation. According to one account the ship measured 38 meters (125 ft) from tip to tail; its diameter was 12 meters (40 ft). The aluminium skin was 0.2 mm thick (equal to four sheets of kitchen aluminium foil) and riveted air tight on a skeleton of thirteen aluminium hoops and longerons of angle profile. Important: at the highest point of the cylinder was a hydrogen release valve that could be opened from the gondola.
Berg and Schwarz came to the agreement that Berg would assume all further costs. He would produce the parts that were to be assembled under the supervision of Schwarz at Tempelhof Airport in Berlin.  It took till the summer of 1896 to get the metal airship ready. Then it was discovered, during the last preparations for the first flight, that the so-called hydrogen gas supplied by a German chemical factory was not of sufficient purity; its specific weight was not low enough in comparison with the air it was displacing and so the loaded airship would not float upwards. Further tests had to be postponed.

Ehrengraeberjuedx
Central Cemetery of Vienna – Israelite part

To the great dismay of his family and business associates, David Schwarz was hit by a fatal stroke while in Vienna on the 13th of January, 1897. The Jewish community of the city of Vienna gave him a funeral with all due honor and a monument at the Zentralfriedhof of the city.
Carl Berg feared he was now stuck with a bizarre and rather fantastic-looking aluminium cylinder whose inventor and promoter had taken his leave forever. However, high-quality hydrogen gas was delivered in Berlin at that same day and Melanie Schwarz came to the rescue. Contemporary sources state that she was a “delicate yet unbelievably energetic lady”. Apart from caring for her family she had always assisted David in his endeavors. Everybody was surprised when she took charge of the project. The preparations for the first flight were resumed resolutely. She engaged a Mr. Jagels, a military man who had, as he said, some experience in ballooning and who was prepared to wager his life for a modest compensation .

Berlin_Tempelhofer_Feld_1907 (1)
Berlin: Tempelhof Field

Filled with almost pure hydrogen gas, the tin cylinder finally elevated itself from German soil in the presence of a vast crowd on the 3rd of November, 1897. A hard and cold wind blew from the east. Jagels had practiced ballooning under simple circumstances; now it was demanded of him to observe a multitude of variables such as wind, altitude, obstacles, engine revs and desired course, while at the same time handling the engine, the drive belts and the rudders.
The ship did lift off, but thereafter things went wrong. The drive belts jumped from their wheels, the propulsion failed and the little ship was carried off, out of control, by relentless and swirling winds to a height of more than four hundred meters. Caught in a basket and at the mercy of the elements, this height is frightening to even the most obliging person and it is understandable that Jagels did the only thing that he could possibly think of: he yanked hard at the cord that opened the safety valve. Unfortunately, just like Blanchard ninety years earlier, he let too much of the good gas escape. The ship, suddenly having lost its buoyant force, dove down and, zigzagging like a punctured child’s balloon, struck the earth at an oblique angle. Fortunately, the skipper was able to jump just before the metal cylinder flattened the gondola against the ground and so saved his dear life.
Melanie showed a remarkably modern talent for public relations. She dispatched the following telex to Carl Berg:
“HYDROGEN FILLING AND LIFT OFF  FULLY SUCCESSFUL” STOP
“SHIP ATTAINED 1000 FT MADE 2 TURNS” STOP
“DRIVE BELT PROBLEM CAUSED PREMATURE LANDING” STOP
“SHIP DAMAGED” STOP
“JAGELS UNHURT“ STOP
“MELANIE SCHWARZ“  STOP

idem1897

Unfortunately, this diplomatic account of affairs could not withhold Berg from withdrawing from the project. He had the remnants of the ship melted. (One of the curious properties of the new metal was that it could be completely recycled.)
Melanie appeared one more time on the stage of history when a certain Count von Zeppelin approached Carl Berg to embark with him on a new project for a metal airship. “This ship will be completely different. It will have an exo-skeleton of aluminum girders that will be covered by  watertight fabric. The gas will be held inside in a row of conventional balloon bags.” Berg was highly interested but felt himself tied by contract to the Schwarz estate. To nullify the obligations, the following proposal was made to the heirs: during a three-year period the Schwarzes would be paid the equivalent of 15,000 Reichsmark, with a royalty of 10,000 Reichsmark for every airship delivered, with a maximum of thirty airships. To their surprise, the generous offer was turned down by the guardian of the Schwarz children, Herr Czillac from Fiume. This male meddling infuriated Melanie and she personally made an appearance at Berg’s headquarters. She was willing to tear up the contract for an immediate payment of 15,000 Reichsmark. “Cash in hand,” she must have reasoned, “that silly old fool Zeppelin won’t ever amount to anything!”
In hindsight, this is a shame, of course, because the thirty airships mentioned in the proposal would already be built by Graf von Zeppelin before 1915, and the previously mentioned three hundred thousand Reichsmark would have been just the sort of money that a mother-alone-with-children could have put to great use.

Epilogue

800px-Wien_-_Staatsoper_(2)
Vienna Staatsopera

All together we may safely state that Melanie did well in the end. Her daughter Vera Schwarz (188?-1964) became with dedicated maternal care a famous soprano, appearing in all the major opera houses of Europe and the United States, often together with Richard Tauber. From 1938 to 1948 she lived in exile in the U.S. Upon her return to Vienna she became a sought-after teacher, giving well attended master classes.
In 2011 a street in Vienna’s 23rd district was named Vera-Schwarz-Gasse in her honour.

Schwarz

http://austria-forum.org/af/Wissenssammlungen/Biographien/Schwarz,%20Davidhttp://www.zeit.de/wissen/geschichte/indexhttp://www.zeit.de/2013/34/zeppelin-erfindung (david schwarz)http://www.britannica.com/EBchecked/topic/1350805/history-of-technology/10452/Petroleumhttp://de.wikipedia.org/wiki/David_Schwarz:

http://en.wikipedia.org/wiki/David_Schwarz_(aviation_inventor)
http://en.wikipedia.org/wiki/Vera_Schwarz

ARENSE, J.L. : Zeppelins en de Luchtscheepvaart”
De Bataafsche Leeuw: Amsterdam
1990   ISBN 90-6707-250-8

“The Metal Airship” article in: Aviation Enthusiast, July 1992

FOR BOOKS ON AIRSHIPS:
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airplane construction interbellum – like Rohrbach and many other pioneers