FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1954
1954 - 1578.PDF
It is only when other aircraft are alongside, to give it scale, that the size of the Stratotanker can be appreciated; the aircraft in the background is a new Boeing KC-97G tankerltransport which, at 173,000 lb., is hardly a dwarf. civil JT3-L engine might be re-rated to run on JP-1 kerosine. It should, at this point, be recorded that there is considerable American opposition to the use of kerosine as fuel. Whatever its advantages may be, it is considered a hazard from the point of view of explosive-vapour release at cruising height. Aerodynamics and controls.—Boeing are certain that the wing of their new prototype is the optimum form for the job. Many years ago it was seen that the B-47 wing could be improved upon, and 21,000 hr of tunnel work—with every form of wing—even tually resulted in the highly efficient wing of the big B-52 bomber. The B-52 wing itself, in fact, bears quite a close resemblance to that of the Stratotanker although the latter aircraft has a more rigid wing structure which greatly reduces droop when on the ground. Owing to this increased rigidity it has been found possible to employ fairly conventional ailerons near the wing tips; the whole control system is discussed below. Large double-slotted Fowler flaps are fitted in four sections; the slot effect being increased by providing a folding gap-strip ahead of the flap. The very high maximum lift coefficient produced by these flaps combines with a moderate wing loading to make possible comfortable operation from fields considerably smaller than are needed for the B-47, without the use of a tail parachute. This will be further assisted by anti-skid brakes and reverse thrust. The wing profile varies continuously from the root to the tip and Boeing are convinced that this is the most efficient form of wing in the world, notwithstanding xival claims by our own industry. The sharp leading edge has thermal de-icing. The entire flying-control system is manually operated. Boeing think this is very important to possible commercial operations and it is certainly a commendable achievement. Lateral con trol in cruising flight is achieved by the surfaces shown in the heading picture on page 697. Each wing carries two spoilers on the upper surface at about 70 per cent chord, their exact posi tion being very critical if trim changes and buffet are to be avoided. These spoilers are power-operated and hinge about the leading edge, to increase drag and destroy the local lift. Quite big differential movements are employed in normal lateral control. As well as their differential use, the spoilers can also be combined together for use as air brakes, ftus saving one set of surfaces over the B-52; in addition the main bogies are also stressed for use as air brakes, termed speed brakes in America. Between the spoilers, and just outboard of the flaps, small high-speed flipper ailerons are fitted to the trailing edge, and these are used for lateral control in conjunction with the spoilers. Further outboard are conventional low-speed ailerons with spring tabs, which cut in automatically whenever approach flap is selected. The tail is fairly conventional. The large fin folds flat to per mit the use of a hangar with 18ft clearance; the moving tailplane has a large trimming range of at least ± 8 degrees and probably more, and carries conventional spring-tab elevators. Landing Gear.—The sideways-folding bogie main under carriage is attached to the rear of the inner rear spar and hinges inwards to lie in the thickened wing root and fuselage. Each bogie has four wheels which are smaller versions of the type employed on the B-52; anti-skid disc brakes are fitted, together with dimpled tyres at a pressure of about 135 lb/sq in. The nose gear is a twin wheel unit with hydraulic steering; it retracts forwards and, like the main gear, is housed in a well which is covered by doors when the gear is down. Equipment.—The main cabin is 90ft long, 18ft more than that of a DC-6B. The floor is arranged to accept various types of seating, six-abreast being possible in the 130 passenger high- density version. Passenger transports would have a large number of small windows, these not only providing each passenger with some view but also being cheaper and lighter than fewer large windows. Boeing also considers such an arrangement "less apt to fail at high altitudes"; British constructors probably take a different view. The present prototype has hardly any windows at all. The main floor is stressed for cargo and the large doors show what can be done in this regard. In addition there is a big pressurized equipment and freight hold under the forward fuselage and another big under-floor luggage and freight com- (Concluded on page 704).
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
