FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1913
1913 - 0154.PDF
l/ycS FEBRUARY 8, 1913. ARMY MONOPLANES REPORT. THE report is now published, dated December 3rd, 1912, of the Departmental Committee appointed to inquire into and report upon the causes of the certain accidents to monoplanes of the Royal Flying Corps and upon the steps, if any, that should be taken to minimise the risk of flying this class of aeroplane. The following is the report:— To the Secretary of State for War, 1. The Committee appointed in the early part of October "to inquire into and report upon the causes of the recent accidents to monoplanes of the Royal Flying Corps and upon the steps, if any, that should be taken to minimise the risk of flying this class of aeroplane," submit the following report:— 2. The specific fatal accidents to which the terms of reference were understood to relate occurred in September of this year to Capt. Hamilton, with Lieut. Wyness-Stuart as observer, atGraveley, near Hitchin, and to Lieut. Hotchkiss, with Lieut. Bettington as observer, at Wolvercote, near Oxford. Particulars of the accident to Major Gerrard on September 13th, 1912, were, however, laid before the Committee, and inquiry was also made into the circum stances of this accident, which, fortunately, was not attended with serious consequences to the flyer. 3. The Committee had before them the reports on the first two accidents, made very shortly after their occurrence, by Maj. Sykes, Commanding the Military Wing of the Royal Flying Corps, and the report on the accident to Maj. Gerrard made by Capt. Paine, Commandant of the Central Flying School. A report on the Oxford accident was made on October 8th, after careful investigation, by the Public Safety and Accidents Investigation Committee of the Royal Aero Club, and copies of this report were kindly furnished by the Club. Col. Holden, Chairman of the Accidents Investigation Committee, also attended before this Committee and gave valuable information as to the evidence on which the report of the Accidents Investigation Committee was founded. 4. The Committee also visited Larkhill and examined there a number of the monoplanes in the possession of the Royal Flying Corps. Officers and members of the Corps attended and gave evidence as to the accidents, and as to questions which arose in connection with the examination of the machines and other matters. The evidence of a number of other witnesses,* some of whom were eye-witnesses of the accidents, while some had inspected the' wreckage of the machines after the accidents, has been taken. Representatives of the British and Colonial Aeroplane Co., the Deperdussin Co., and the Gnome Engine Co., attended and gave assistance to the Committee in regard to the objects of the inquiry. 5. In pursuance of the chief purpose of the inquiry, as set out in the terms of reference, the Committee have given careful considera tion to special features characteristic of the monoplane which may affect its safety. The conclusions and recommendations of the Committee with regard to these follow later ; it will be convenient first to deal with the three accidents investigated. 6. The Graveley Accident.—The machine destroyed in the accident at Graveley was the Deperdussin monoplane which received the 2nd prize in the Military Aeroplane Competition. It was fitted with a 100-h.p. Gnome engine. Some particulars as to the earlier part of its flight on the morning of the accident are given in Major Sykes' report. From this it would appear that over Stevenage the engine had been stopped, and the machine was planing down. A few moments before the accident it is stated by an eye-witness that he saw it make a somewhat steep dive and then flatten out again with the engine running. Almost immediately afterwards pieces were seen to fall from the machine, which, from the description given of their appearance, are inferred to have been portions of the cowl. The next moment the left wing collapsed, and the machine fell, apparently nearly vertically. The collapse of the machine was accompanied by a loud noise. 7. The parts of the machine found in or near the line of flight included : — Some broken tappet-rods. An aluminium packing piecs from between the plate by which the outside left wire is attached and the main spar of tie wing. Portions of the engine cowl. Two front chassis struts. The following is a list of the witnesses examined : Graveley accident, Mr. R. L. Charteris. Col. R. Whigham. Maj. H. R. M. Brooke- Popham. Lieut. G. de Havilland. Serjt. F, Ridd. rard. Oxford accident. Accident to Maj. Ger Col. H. C. L. Holden, C.B., Maj. Gerrard. F.R.S. Lieut. C. Randall, R.N. Maj.H.R.M.Brooke-Popham. Capt. C. R. W. Allen. Capt. R. R. S. Rowell. Lieut. G. de Havilland. Serjt. F. Ridd. The following also gave evidence :— Lieut. Fox. Mr. L. Coanda, representing the British and Colonial Aeroplane Co. Lieut. J. C. Porte, representing the British Deperdussin Aeroplane Co. Mr. R. Bertaux, with Mr. G. Holt Thomas, representing the Gnome Engine Co. 8. On examination of the machine on the ground it was found that the upper wire, on the left wing, carried to the furthest point of attachment from the body had been drawn from its ferrule and was loosely coiled nearly twice round the engine ; the corresponding lower lift wire had come away, the bolts in its attachment to the spar having been sheared through. Seven or eight tappet-rods, in series, were found to be broken, and the valve rockers and brackets were bent backwards, as if while the engine was revolving they had struck some fixed part of the framework, some of them being fractured. The star-shaped frame in front of the engine, carrying the third, front, bearing had been torn away. One blade of the propeller was embodied in the ground nearly to the boss. The engine could not, therefore, have revolved after it struck the ground, and the damage to the engine above described must presumably have occurred in the air. The other blade of the propeller was broken, and a V-shaped piece, some 2 ft. long by 3 to 4 ins. wide at its widest part was missing. In spite of inquiry and diligent search along the route followed this piece has never been iound. 9. From the information before the Committee it has not been possible to determine definitely the primary cause of the accident, but all the evidence points to the probability that it arose from some damage to the engine or its mounting, or to the propeller. It may have originated in fracture of some part of the engine, possibly a tappet rod. The valve rocker may then have swung out and fouled the cowl, the clearance being small. * Parts of the cowl found were scored heavil)' on the inside, and in one place there was a hole right through it. Assuming that from some cause the cowl was caught by the rotating engine, the remainder of the accident admits of explanation. Stays to* the mast to which the upper wing wires were attached came forward in this machine to points immediately above the cowl. One of these forward stays may have been forced back, putting a strain on the outer wire above the wing and drawing it out from its attachment. The shear ing of the bolts of the attachment of the outer lift wire may have occurred immediately after, or may have followed owing to flapping of the wing. From the National Physical Laboratory report, and from the evidence of the representative of the Deper dussin Co., it was clear that the wing would not then be able to bear the stresses falling on it. The wing would thus give way and the machine fall. The noise heard was probably caused by the tearing away of the cowl or the breaking of the wing. The loose upper wing wire at some period became coiled round the engine. 10. A possible alternative explanation is that vibration of the engine may have been set up, whether from fracture of the propeller or other cause, such as the method of supporting the front bearing. The detachment of a piece of the propeller of the size above indicated would give rise to considerable vibration in the engine and its supporting framework, which would probably be quite sufficient to do serious damage to the light frame carrying the front bearing and to account for the tearing away of the cowl and the subsequent collapse of the machine. No reason for the initial fracture of the propeller can, however, be suggested from the evidence before the Committee. The method in which the engine was mounted in this machine has also been carefully investigated. This more general question is dealt with later. 11. Such parts of the engine as were available were sent to the National Physical Laboratory for examination. These did not include, however, the fractured tappet rods. The engine was much damaged, and it was impossible to determine what part of it might have fractured first. 12. The Oxford Accident.—The inquiries of the Committee have confirmed the account of this accident given in the report of the Royal Aero Club. The circumstances may be briefly stated. The aeroplane was one of two Bristol monoplanes which passed through the military trials and obtained a prize of .£500. The engine was an 80-h.p. Gnome. The aeroplane was seen flying over Port Meadow, Oxford, at a height of about 2,000 ft. The engine was then shut off, and it began to plane down, apparently in a normal manner. When it reached a point distant about 600 ft. from some trees bounding Port Meadow, and at a height estimated by an eye-witness as about 700 ft. (500 ft. in Royal Aero Club report), the descent became much steeper, and at a height of about 200 ft., almost over the trees, the fabric of the right wing burst, or the rear portion of the wing gave way, and the machine fell. 13. A steel strap from the machine was picked up in Port Meadow, about 330 ft. from the point where the aeroplane struck the ground. A number of pieces of wood, fragments of the wing, were also found in Port Meadow in the vicinity of the strap. Some * The minimum amount of clearance on the machine is stated by the Deperdussin Co. to have been iTs^ ins. This agrees with the amount measured on the similar machines at LarUhill, in which the clearance between the valve- rocker and the bottom strut of the noseplate is if ins. The valve-rocker strikes this strut when swinging free from the tappet rod. 154
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
