FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1964
1964 - 2272.PDF
FLIGHT International, 20 August 1964 287 A European approach to the V/STOL transport: the Short PD.55, with four R-R Darts and 24 RR.I62 lift jets, which was an entry in the N&MR-4 competition produce the jet-lift aircraft illustrated on the last page of our drawings. Last October it was agreed by the British and Federal German Governments that Hawker Siddeley's former D.H.129 design team should collaborate with Dornier-Werke in a joint development programme. The Government agreement was signed on April 13, and is aimed at "expanding the Do31 programme in such a way as to suit the purpose of the two Governments con- cerned." The cost of the study is being shared by Britain and Germany. This collaboration will certainly improve the Do31 (one advantage may be the use of the Hatfield-developed lift pod with RB.162s lying on their sides), but the British participation appears to be for mainly political reasons. The RAF has never expressed interest in the NBMR-4 specification, which is too small for its own require- ment. The latter, OR.351, calls for an optimized aeroplane able to replace the motley collection of Transport Command equipment already in use for tactical purposes, whilst retaining a ferry range long enough for it to fly out from Britain to any theatre overseas. This calls for an aircraft as big as a C-130, and the Air Staff were most anxious for it also to have rough-field STOL performance and the highest possible transit speed. The answer was an all-jet machine with blown flaps and vectored thrust. Such an aircraft appeared a logical development for military forces, but it was obvious that it would be too large for the European nations and uneconomic for civil operators. The stage inevitably seems all set for another short-run programme up at the top of the learning curve, but OR.351 appears so vital in the context of Britain's responsibilities to quench brush-fire wars that we have no option but to go ahead and build it. We may be sure nobody else will build it for us. In March 1963 the contract award for the Hawker Siddeley 681 was announced. The Avro Whitworth Division are responsible for this aeroplane, which will be powered by four Rolls-Royce Medway turbofans with switch-in deflectors. Each engine will have an initial thrust of some 17,5001b, and considerably more powerful versions are in prospect. The 681 should be an exceedingly flexible aircraft, carrying very heavy loads when flying from runways, yet able to operate with reduced payload into unpaved strips only a few hundred feet in length. Provision for in-flight refuelling is obvious, and it is understood that the 681 is also being designed for ultimate VTOL operation using lift-jet packages beneath the wings, should a requirement arise for such capability. It is unfortunate that the US Air Force has at present no require- ment for such an aeroplane; practically all the MATS airlift operates from high-strength runways with a minimum length of 6,000ft. There is a limited need in the US for a V/STOL transport, but this would not have to be as large as the 681 and the Vought/ Hiller/Ryan XC-142 tilt-wing may well prove adequate for all three US Services. The XC-142A has been built as part of Support System 478A for the all-weather supply of troops and combat equipment under assault conditions, and weighs no more than 34,0001b (100 miles mission radius) to 38,0001b (300 miles) in VTOL operation. The much larger BLC-130 blown-flap conversion of the C-130 was not adopted in America, although British Aircraft Corporation proposed it in a modified form to meet OR.351. Apart from the Douglas C-133, which was bought in small numbers principally to carry ballistic missiles, the most productive aircraft in MATS service are the fan-powered Boeing C-135 and Lockheed C-141, both of which can carry payloads of the order of 90,0001b over intercontinental ranges. The only obvious short- coming of these aircraft is that they cannot accommodate a number of important items of military equipment; the Boeing has a side loading door 10ft 6in above the gound and the Lockheed has an internal cross-section only 10ft 3in wide by 9ft lin high. MATS needs a bigger aeroplane, and for at least 18 months studies have been in hand which began as relatively conventional CX-4 and CX-X enlargements of the C-141 and by the spring of this year had led to a variety of advanced CX-HLS (heavy logistics support) schemes embracing various types of laminarization and boundary- layer control and specifying four or six high-ratio turbofans in the 30,000 to 40,0001b-thrust class. The required load is 100,0001b in a space 100ft by 16ft by 13ft 6in. A Belfast with a 15ft body plug, a new wing and BS.100 engines could meet the require- ment beautifully, and at minimum cost; but this aeroplane is not American. Intense activity during the past six months has now resulted in the programme being reoriented to a more urgent time-scale, with consequent elimination of the features requiring a long lead-time. In April the USAF Systems Command awarded three-month study contracts to Boeing, Douglas and Lockheed-Georgia for the CX-HLS airframe, and to General Electric and Pratt & Whitney for a suitable powerplant. Pratt & Whitney, incidentally, have centred their studies on the relatively conventional STF-200 turbofan with a hot/cold ratio of two, while GE have concentrated upon the GE1/J1 with twin gas generators driving a single-stage fan with a ratio of ten; in some of the studies with the 24,5001b- thrust GE engine the gas generators would be mounted inside the wing, driving the ducted fan hung behind the trailing edge. There have been scores of CX studies, and an indication of the numbers involved is provided by a Lockheed proposal dating from April: with the P&W engine a 700,0001b aircraft could carry 130,0001b payload 4,000 n.m. cruising at 440kt at 30,000ft, or 100,0001b payload 4,690 n.m. at 360kt; with the GE engine the same aircraft could carry 100,0001b payload 8,630n.m. at 360kt (a 24hr endurance) or 9,000 n.m. at 440kt. ~~In view of the fact that it is widely felt in the Pentagon that there should be as many CX-HLS aircraft as there are C-141s—of which there are 132 currently on order—the US airframe industry regards the programme as one of some consequence, particularly in view of its obvious potential interest to commercial operators in the next decade. On August 3 Douglas announced that they had joined forces with North American Aviation to improve their chances, NAA having the role of major subcontractor and also assisting Douglas in the HLS design and development phase. A decision on the powerplants and airframes will have to be taken very soon if the resulting aircraft is to become operational at the desired date of June 30, 1969; and it may well be that long before this date the US Department of Defense will be well ahead with a draft specifi- cation for a fully-laminarized successor with a range greater than 15,000 miles. A gentle note to end on: a BUI33 Jungmeister recently photographed amid a verdant setting in the land of watches, chocolate and winter sports. The same air force also trains on the Mirage III-BS
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
