Aviation of World War II
Boeing 377 Stratocruiser
Emphasis that our friends on the other side of the Atlantic do not allow grass to grow under their feet is evidenced by the fact that they have already developed a commercial air liner from the famous B-29 Superfortress—what is more the "military" prototype of the new machine has been built and is at present undergoing test. Boeings say that "all present models of the 377 will be for military service," but nevertheless this should not blind anyone to the fact that the Americans have the first ol the greater post-war super-transport aircraft already built and flying. What is more, the Stratocruiser is a larger and more commodious and higher-powered aircraft than our British Tudor and Hermes which, one may reflect, are not yet built.
We have no doubt whatsoever that if the Government would authorise M.A.P. to give our aircraft manufacturers carte blanche (within the limits of war requirements) to produce the sort of post-war commercial aircraft they want to produce, then, within a year, we could have flying at least two, probably three, world-beaters. In the face of the sort of competition of which the new Stratocruiser gives concrete evidence, it is essential that this country of ours gets off to a start which will not penalise further our already heavily handicapped industries. Our start of this war should paint a sufficiently vivid picture of the costs of unpreparedness. There is nothing to show that post-war aeronautical rivalry will be any less cut-throat than its wartime image—if anything, the reverse is indicated.
Present Indications of Future Trends
There are so many indications of the peacetime commercial trend of the world that it would seem impossible for anyone of unveiled perception not to see the way things are heading. As an example: France is at present eager to buy American aircraft. These, we will grant, are military machines—but, we must ask, are British aircraft manufacturers so pressed that we cannot afford to supply France with aircraft for her needs? We do not need to ask if our aircraft are inferior to American types. But if France is prepared to go at once to America for her military aircraft, is there any reason why she should not do the same thing for her commercial machines? Unfortunately the answer is No. America has more to offer than we have, and we have no reason to believe that we can give the U.S. any start she wants and still beat her. We must repeat: in the face of the sort of competition of which the new Stratocruiser gives evidence, we cannot afford to rest on our laurels. There is no such thing as loyalty in commercial warfare—a bitter lesson which, seemingly, many people have yet to learn.
The new Boeing machine is a direct development of the Superfortress, having the same wings, tail unit, and landing gear, but, following the Avro precedent, has an entirely different fuselage which is 12ft. longer and of more than double the volume of the B-29's. Many outstanding claims are made for the aircraft, and presumably, justification for the operative figures advanced has been given by actual test—it is to be hoped that such is the case, as a great deal can be evolved by judicious use of a slide-rule and a little wishful thinking.
Nevertheless, the direct operating Vost is quoted as being 1 cent (0.557d.) per passenger/mile for ranges of the 3,000-mile order. This passenger/mile cost is an almost ridiculously low figure, and we must assume that by the phrase "direct operating cost" Boeings mean the bare running cost without regard for the cost of maintenance, crew salaries, nor any of the other multifarious charges consonant with the operation of commercial aircraft. However, no matter whether the figure is but the bare running cost, it is still a very low one and furthermore, one that would appear difficult to match, let atone beat.
On top of this, the Stratocruiser is claimed to have a normal cruising speed of 340 m.p.h. with a maximum of 400 m.p.h., and an operating range (with "abundant" fuel reserves) of 3,500 miles. This would allow nun-stop flight between New York and London or New York and Los Angeles without difficulty, and at a speed faster than the economical cruising speed of a Mosquito!
The performance is made possible, according to the makers, by virtue of the Boeing 377 low-drag wing and other aerodynamic advancements already proven on the Superfortress. Engines are said to be of 2,800 rated horsepower with 3,500 b.p. for take-off, and although mention is not made of their make, one may hazard a guess that on the Boeing precedent of the Fortress, Clipper, Stratoliner and Superfortress, they will be the new 18-cylinder units recently announced by Wright. Flight on three engines only is claimed to be,possible at 20,000ft.
Pressurised, Two-deck Fuselage
As the machine is intended for operation at altitudes up to 30,000ft., the fuselage, except for the lower rear cargo compartment, is pressurised to a value equivalent to atmospheric pressure (but not temperature) at 8,000ft. For descent, regardless of the aircraft's rate of descent, the cabins pressure is increased at a slow, measured ratr in order to maintain passenger comfort.
Precedent for the two-deck fuselage arrangement is given in the Curtiss-Wright 20 model, but Boeings have gone rather further—as, of course, the size of their aircraft allows them—and utilise both decks for passenger accom modation, the floor which spans the inter-section of two eccentric circles which make the fuselage cross-section providing a strong lateral tie against internal pressure. Pressure difference between 8,000 and 30,000ft. is no less than 6½ lb./sq. in., which, when acting over the entire area of the fuselage surface, gives a total of a good many tons, and there is no doubt that the tie provided by the floor of the upper deck is a very valuable stressing quan tity. The lower section has a diameter the same as that of the B-29, whilst the upper section is somewhat larger with a diameter of 11 ft.
Boeings claim that the two-deck layout, by allowing three cabins, permits unusual flexibility in arranging the aircraft to meet various operational conditions. Three alternatives are listed : —
(i) High speed, low fare, transport for 100 passengers in the three cabins. Ample space for cargo and luggage is said to be still available, and, as the passenger capacity is approximately equal to that of two modern-type (American) streamlined railway day-coaches, and fares could be made sufficiently low, operators could compete for this big field of traffic.
For additional cargo space, one lower cabin could be devoted to cargo, giving an extra 750 cubic feet of space, but reducing the passenger capacity to 86.
(ii) Luxury sleeper with 72 day seats or ; rear lower cabin furnished as , and the lower forward cabin used as galley, crew quarters and cargo hold. This arrangement is for long trans-ocean flights. By using the lounge for additional passengers, the day-time capacity could be increased to 86.
(iii) All-cargo transport with a drive-up ramp to the rear, and internal cargo-handling equipment. This version gives a usable cargo volume of 3,000 cubic feet and a maximum cargo payload of 35,000 Ib. It is claimed that the direct operating cost of this model will be about 5 cents (2.8d.) per ton/mile. Again, an amazingly low figure which, to say the least of it, appears optimistic.
Dimensions of the Stratocruiser are: Wing span, 141ft. 3in.; length, 110ft. 4in.; height, 33ft. 3in. All-up weight is given as 130.000 lb., and with a wing area of 1,735 sq. ft. (aspect ratio is 11.5) this gives the very high wing loading of 74.9 lb. /sq. ft., but take-off is presumably assisted by special flaps as used on the Superfortress. Take-off power loading would be 9.28 lb./h.p.