Tag Archives: 1930 airplanes


In 1994 I bought a handsome collection of short biographies of aviation pioneers, from which I quote:

The Wing Man: David R. Davis – 1894(?) – 1972  [1]

“David Davis grew up as a sickly child who was advised to spend as much time outdoors as possible. While a young man, he was sent on an educational camping trip with a tutor, during which they retraced the route of Lewis and Clark. [2]   When he was fifteen he moved to California with his mother. Their home was near Los Angeles where [aviation pioneer] Glenn Martin was experimenting and Davis would often help Martin ground-handle his plane.
“In 1911 Davis made his first flight and four years later he bought his first aeroplane. During World War I he served in the Army.  After the war he became a barnstormer before joining with Donald Douglas in 1920 to start the Davis-Douglas Airplane Company  [Davis put up $40,000.] This venture failed and Davis was completely wiped out with the Stock Market crash in 1929.”

About the period with Douglas, Oliver E. Allen writes in “The Airline Builders“:[3]

“…In 1920 Douglas was ready to start his own firm. He went to Southern California with less than $1000 because he felt at home there and one could fly there all year. It was however a bad time to start an aircraft factory anywhere. Douglas tried to borrow money everywhere, until a friend introduced him to David R. Davis, a well to do young man from California who wanted to have an airplane built for a non-stop transcontinental flight.”


“The two men founded the Davis-Douglas Co. and rented an office. Afterwards they moved to a loft over a lumberyard in Los Angeles. There they constructed the Cloudster. This airplane had one unique property: it was the first plane that could transport a load greater than its own weight.  During the first [attempt of the] transcontinental flight the [Liberty] engine broke down and Davis had to crash land at Fort Bliss (Texas). In 1923, when he was ready for a second attempt, two army officers had already completed the non-stop flight with a Fokker T2. Davis lost interest and withdrew from the company…”

Quoting again from Longyard:

“…Davis took an everyday job to support his family but he never gave up his penchant for airplanes. He tried to develop a variable pitch propeller, but lack of funds hampered his efforts. By the late 1930s, he had developed a theory of aerofoils that he thought could greatly increase the efficiency of wings. He tested model sections mounted on a borrowed car.
Through Walter Brookins, he was able to convince Reuben Fleet [of Consolidated Aircraft] of the possibilities inherent in his new wing. Fleet had a wing section tested at the California Institute of Technology where the scientists said the wing was an impossible 102 percent efficient. They disassembled their windtunnel to see what was wrong! Fleet ordered that his next flying boat be built with a ‘Davis Wing’ – a million dollar gamble. In 1939 this plane [the Corregidor] was flown by an amazed test pilot who said it handled like a fighter.”

Altogether not a very complete picture of what exactly went on with the Davis-wing. Remember this was the time before Google, Internet and Wiki. In those days one had to search in libraries and magazines. So imagine what a surprise it was when one day in 1996 I found a letter in the mail from my old friend of Canadian days John Galipeau, whom I had not seen for thirty years. He had heard of my interest in the Davis wing and he had visited the San Diego Air & Space Museum, where he had found fresh information for me, such as the photograph of two of the principal actors shown above: Donald Douglas and David R. Davis.

to be continued…

[0] Picture of Cloudster is shown at the top of the article. Note the big belly needed to store all the fuel.            Pic credit: Wiki
[1] The collection of short biographies is from: William H. Longyard, “Who’s Who in Aviation History“, Shrewsbury, Airlife, 1994.
[2]  Two famous explorers, who were sent out by Thomas Jefferson in 1803 to find a route from St.Louis to the Pacific Coast.
[3] Chicago, Time/Life, 1981, here translated from the Dutch edition.



I got interested (again) in aviation history when I bought thirty years ago at a jumble sale an old scrap book with photographs of the Dornier Do-X. The Germans have always been very proud of that boat, but of course in 1932 it failed dramatically where five years earlier Charles Lindbergh had succeeded without apparent effort: a simple non-stop jump across the Atlantic. I wondered why this could be so and started to read (+ collect) books about 1930-flying boats and airliners. What were the factors that determined their long-range performance? How fascinating that era was!
Next I got into a correspondence with a certain Don Middleton, a British aviation journalist, who had stated in an English monthly that the amazing long range of the Consolidated Catalina patrol boat was due to its ‘Davis-wing’. Based on general data from Jane’s ‘Fighting Aircraft of WWII’ edition I undertook to compare four contemporary transport planes: the Douglas DC-3 and DC-4, and the Consolidated Catalina and B-24 Liberator, and proved to him that Catalina’s extreme performance was based on two factors: its light construction (empty weight approximately 50% of take-off weight) and its slow cruising speed, which was right at the optimal economic flight point (maximum  CL/CD ratio). The other three planes, for commercial or operational reasons, all cruised faster than their most economic speed and as a consequence had a comparatively shorter range. The Cats were slow, real slow, to the exasperation of their crews. However, slowness could also be advantageous: they were able to shield the ships they were escorting by circling tightly around them, outmaneuvering in this way attacking German and Japanese aircraft that were much faster.

The PBY Catalina had no Davis-wing and I think I proved it, but Middleton never entered into a serious discussion and suggested I submit my paper to the Royal Aeronautical Society, which of course was a bit much. Later on I learned he disliked smart asses like me who argued from theory: he had been a skilled aircraft worker at de Havillands himself and a RAF engineer during the war.
Of course the Davis-wing was used on the B-24 Liberator. Next blogs will summarize what I know about it. The inventor, David R. Davis, [1] appeals to me because he was obviously a maverick: he worked outside the official circuits of Universities and NACA. Apparently he had a mind of his own. As a result however, descriptions of his work are hard to find in official literature (like Abbott & Doenhoff; maybe Durand mentions him?). Apparently his wing had extreme low drag at small angles of attack (laminar flow?), which is remarkable, because long range (like Catalina’s) is usually associated with low engine power and therefore relative large angles of attack. So there were things here which were not quite clear to me. I wanted to know more about the wing profile: it must have been very thin with maximum depth near the middle of the chord. How can thin wings be made strong enough for long spans? This was the state of my comprehension until I found more information.

[1] A word of warning: there have been other aviators of fame with the name Davis. So is our man not to be confused with the unfortunate pilot Noel Guy Davis, who crashed short after take-off for a trans-Atlantic flight in 1927, aboard a Keystone Pathfinder (N-X179) airplane called American Legion.
[2] picture: PBY5 Catalina; credit: Wiki.


In the 1930’s the above traffic situation occurred frequently in the canals of Amsterdam: the Fokker Aircraft factory was located in Amsterdam North, a residential and industrial section of town without an airfield, while Schiphol Airport was to the south of the city, on the bottom of a reclaimed lake. For flight tests newly built Fokkers had to be transported through the wondrous and winding canals of the old city. Sometimes, after heavy rainfall, Schiphol was too marshy and flight tests had to be relocated to Welschap, near Eindhoven, a distance of 70 miles or so to the south.

You can read about the tests at Welschap in the revised ‘album’ of Erich Schatzki’s life, when you click here:  alifeofflight2.pdf

Erich Schatzki loved the new country that he had settled in for a short interval of time. Relentlessly moved on by the unfolding of history, events took him eventually to the United States and then to Israel and back again to the USA – like a pendulum, going multiple times back and forth.

For the new data which I was able to add to the earlier description of Schatzki’s life, I am indebted to my old friend Wim Snieder, the writer of the only comprehensive bibliography of Dutch aviation history: “In Vogelvlucht” / Geannoteerde bibliografie over de Nederlandse luchtvaart, vanaf 1784. Uitgever; Canaletto/Repro Holland; 486 pages, ISBN 9789064697340

1939: Erich Schatzki Album


As a little boy in Holland I was enraptured by the original shape of the Fokker G-1 fighting plane of 1939. A few years later I became a (small) close witness to the atrocities of the war, as some of my schoolmates and good neighbors in the street where I lived in Amsterdam were deported because they were Jewish. (They never returned.)
Dr.Erich Schatzki

While living now in California and enjoying my own ‘Indian Summer’, I found on the web the designer of the G-1, Erich Schatzki. I also learned that he was a Jewish exile and that he and his family had been on the run for the Nazi’s since 1934. I set out to find more facts about his life.
I have collected these in an ‘Album’, a collection of factual items and a description of some of the fascinating people that he met in his long, adventurous life.

I have added my findings in a new file on my website today. If anybody can tell me more, or if somebody wants to correct an error, please leave a note!



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:



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.


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.