2,239 research outputs found
Towards the tumble resistant microlight
No full textThe tumble mode is a pitching departure from controlled flight which leads to a pitch autorotation that is generally unrecoverable – resulting in vertical ground impact, usually preceded by in-flight breakup (the mechanism for which, surprisingly, can sometimes prevent loss of life). This was identified in work led by the British Microlight Aircraft Association beginning in 1997 as a response to a number of fatal accidents in Rogallo winged microlight aeroplanes, although the tumble is also known to occur to hang-gliders. This paper explains how this class of aeroplane is controlled, and how it has been found that they can enter the tumble mode. The mechanism by which the tumble can be entered is described. This has led to work showing how flight testing can be used to establish and demonstrate resistance to tumble entry – particularly important with increasing number of very high performance flexwings. These flight tests will be explained, together with the significance of the results. Recent accident investigation work has also shown a new mechanism of tumble entry, through partial failure of the A-frame structure and the pitch-trimmer mechanism. Also described is a possible relevance to well known historical accidents to flying wing aeroplanes– specifically the YB-49 and dH-108, and discovered data on the characteristics of the BKB-1flying wing glider; are also described
Use of airborne vehicles as research platforms
No full textThis is the accepted version of the following chapter: Gratton, G. 2012. Use of Airborne Vehicles as Research Platforms. Encyclopedia of Aerospace Engineering, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/9780470686652.eae604/full. Copyright @ John Wiley & Sons 2012.The use of aircraft is often valuable to position airborne sensors or to conduct experiments in ways not possible purely on the ground. An airframe, typically an older one, must be selected then adapted to the role – likely to include inlets, windows, structural changes, power supply, computing and data recording capacity, and likely the provision of external hardpoints. Once the research vehicle is created, the instruments on board will require calibration, either in isolation or by intercomparison against already calibrated instruments on board another aircraft. This calibration process will continue throughout the life of the airplane. Additionally, an operating organization must be created and obtain any necessary organizational approvals. For some specialist applications, unmanned aerial vehicles (UAVs) may also be used, which carry some special considerations of autonomy and interoperability, but similar concerns of instrument, vehicle, and operational integrity
The tumble mode - where test pilots fear to tread
No full textFollowing a fatal accident in 1997 and identification of common patterns in several (usually fatal) previous accidents the AAIB (United Kingdom Air Accidents Investigation Branch) asked the BMAA (British Microlight Aircraft Association) to pursue a course of investigation into the tumble mode, which had been attributed as the primary cause of that fatal accident.
The tumble mode is a peculiarity of weightshift controlled aircraft - that is flexwing microlights and hang-gliders. It is a departure from controlled flight leading to a nose-down pitch autorotation: pitch rates of 400°/s are known. When a tumble occurs in a microlight aeroplane, it is rare for the crew to survive and loss of the aircraft is universal
Gratton-Wilson, W A S, VX10607
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/388664Surname: GRATTON-WILSON. Given Name(s) or Initials: W A S. Military Service Number or Last Known Location: VX10607. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 2701.211434
Item: [2016.0049.20957] "Gratton-Wilson, W A S, VX10607
A theoretical and experimental appraisal of airworthiness evaluation techniques for small light aeroplanes
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by the University of Southampton.A thorough evaluation of the airworthiness of a manned aircraft is vitally important, regardless of the size or function of the aircraft. However, the methods used in light and particularly microlight aircraft certification were largely based upon rules of thumb or methods better suited to larger, higher energy, aircraft programmes.
A programme of research has been carried out to develop means by which microlight aircraft certification could be carried out appropriately to this class of aircraft.
The stall and immediately post-stall behaviour of an aircraft are shown to be a function of the deceleration rate prior to the stall; therefore it is necessary to use a representative deceleration rate when determining the acceptability of stall and post-stall handling qualities. This research has found means by which the range of deceleration rates likely to be seen in a particular type can be estimated, so that flight test programmes can ensure these rates are included, and thus aircraft are confirmed to have acceptable stalling characteristics.
Weightshift controlled microlight aeroplanes, using a Rogallo type wing, rarely show a conventional (square law) relationship between stalling speed and loading; the reason being identified as aeroelastic deformation of the wing with loading. A means by which stalling speed may be estimated for such aircraft at a variety of loadings has been developed. This will allow designers the maximum flexibility in determining operating limits and shows how the stall speed at various flight conditions may be predicted in aircraft operating documentation.
The spin is a serious and potentially fatal mode of flight; a spinning evaluation, even for non-aerobatic aeroplanes, is therefore essential. A best practice has been developed and tested for the spin-resistance or spinning evaluation of microlight aeroplanes, including equipment, aircraft and crew preparation, and reporting. The developed methodology is shown to be successful, using the results of certification flight test programmes, and the in-service safety record of aircraft which had been evaluated using these methods.
The tumble mode is a little known mode of departure from controlled flight experienced by weightshift controlled microlight aeroplanes. It has been a very significant factor in fatal accident records, being non-recoverable without the use of external safety devices. The mode consists of a nose-down autorotation at a rate of up to 400°/s. The tumble entry mechanism is explained, and advice to operators developed which should prevent tumble entry. Evidence is shown of the nature of the developed tumble – both modelled and through wind tunnel results, which explain how the autorotation occurs. It is also shown how this theory may be applied during testing of an aircraft to develop a tumble resistant aircraft
Gratton, G A, VX18091
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/388663Surname: GRATTON. Given Name(s) or Initials: G A. Military Service Number or Last Known Location: VX18091. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 40768.211433
Item: [2016.0049.20956] "Gratton, G A, VX18091
Gratton, J W, QX16802
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/388661Surname: GRATTON. Given Name(s) or Initials: J W. Military Service Number or Last Known Location: QX16802. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 33602.211431
Item: [2016.0049.20954] "Gratton, J W, QX16802
Horne, Gratton Dennis, TX8103
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/393300Surname: HORNE. Given Name(s) or Initials: GRATTON DENNIS. Military Service Number or Last Known Location: TX8103. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 19436.214069
Item: [2016.0049.25593] "Horne, Gratton Dennis, TX8103
O le fagu aitu
No full textOriginally published in Samoan in 1891 with title: O le fagu aitu.
"Sa tusia e R.L. Stevenson, O le tusi tala lea sa Maliu i Vailima, Tesema 3, 1894"--Cover.
A story written by the author who lived in Vailima, for the Samoan "Sulu" First printed in the 'Sulu", May 1891. Translated by the Reverend Mr. Gratton
Translation of: The bottle imp
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