FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1971
1971 - 2786.PDF
1014 FLIGHT International, 23 December 19/'I Man-powered flying as a sport By Dr K. SHERWIN* I T is NOW TEN YEARS since the first true man-powered flight took place, when the Southampton University aircraft covered a distance of 50yd from take-off. That we should now be in a position to discuss practical man- powered aircraft suitable for sports flying is an indication of the many developments that have taken place since then. The ten aircraft of differing configurations, and with wingspans ranging from 64ft to 120ft, which have achieved man-powered flights are described in Table 1. None of these aircraft has complied with the require ments of the Kremer competitions that initially defined their performance criteria. There are several reasons for this, but the major one is the increase in power required for the climb. All the aircraft listed in Table 1 would need to fly at, say, 2ft-3ft altitude for most of the course in order to take advantage of ground effect, then climb back to the 10ft required at the finishing point. Power for climbing can be related to the cruising power and the angle of climb & by the simple relationship: — climb = "cruise I 1 L/D X £ ) 57-3/ so that with an L/D ratio of 50-plus, as achieved by the later types, the climbing power for a 1° climbing angle would be approximately twice that for cruise. 'Department of Mechanical Engineering, Liverpool Unversity Table 1 Wing Aspect Empty Flying Wing Span area ratio weight weight loading Country (ft) (sqft) (lb) (lb) (Ib/sqft) Sumpac 80 300 Puffin I 4 330 Puffin II 93 390 Linnet I 73 288 Linnet II 3 280 Linnet III 83 325 Linnet IV 79 — Malliga Aircraft 64 262 Santa-Meada OX-1 73 290 Weybridge Aircraft 120 480 156 17-9 30 0 128 118 140 105 99 111 119 113 122 269 267 290 230 225 232 237 239 245 276 0-90 0 81 0-78 0 80 0-80 0-72 0-91 0 85 0-57 First take-off by the Malliga aircraft was in July 1967. That flight covered 150yd at a height of lft-2ft In this respect the later £5,000 Kremer competion in which competitors have to complete two "slalom" runs is in reality probably more difficult than the £10,000 Kremer competition which retained the initial figure-of-eight course- It should not be inferred from these remarks that the Kremer competitions constitute an impossible task, but there must be further developments before they can be won. The competitions themselves do not provide the necesary encouragement for such developments. The problem is that all the aircraft have so far been designed for a direct attempt at the competition, where the pilot is required to provide all the power for the flight unaided by any help from the atmosphere. In order to extend flights the aim of the Kremer aircraft has been to reduce power input by increasing wingspans, resulting in aircraft that are subject to the following restrictions: — (1) They can be flown only in very calm conditions, either at dusk or early in the morning, so limiting flying experience needed for competition attempts. (2) They can be entrusted only to expert pilots, so possibly limiting the power available for propulsion. (3) Projects can be attempted only by large, dedicated groups. It is estimated that the Wey- bridge aircraft involved 10,000 man- hours of construction time. (4) Such aircraft require that large workshop/hangar and flying-field facilities are readily available. The last two restrictions obviously limit the number of such aircraft that can be built and, because of the present difficulties of the aerospace industry, future attempts at building aircraft of the size of those of the Weybridge or Toucan groups are not envisaged. UK UK UK Japan Japan Japan Japan Austria Japan UK First flight 1961 1961 1965 1965 1967 1970 1971 1967 1970 1971
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
