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]
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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