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Aviation History
1962
1962 - 1023.PDF
FLIGHT International, 28 June 1962 1021 AERO ENGINES 1962 General Electric J79-IIA pleted its Preliminary Flight Rating Test. GE announced this last month, and USAF Aeronautical Systems Division are completing their evalua tion of the engine concerned. The requirement of propulsion at a cruis ing Mach number of 3 (2,000 m.p.b.) has necessitated the introduction of new materials and honeycomb structures, and the overall design of the complete powerplant represents a "state of the art" advance. The PFRT was run at the RTF of Arnold Engineering Development Center according to a new schedule of 68hr which includes endurance running in a simulated cruise regime, and inlet conditions equivalent to M3 at 65,000ft were sustained for 18hr. In addition the engine "underwent about ten times more afterburner operation than was required of earlier turbojets." Prototype YJ93-3 engines have run many thousnds of hours at Evendale, and in flight beneath a B-58 in a pod which includes the B-70's HamStan intake control system. Delivery of YJ93-3s to Palm- dale, for ground running in the first XB-70. has been in progress since April. General Electric CF700-2B CF700 Essentially a CJ-610 turbojet with an aft-fan unit added, the CF700 ran in May 1960 and completed a 150hr type test in May 1961. Priced at $75,000, the CF700-2B is being promoted for a very wide range of subsonic applications. Apart from Bell (lunar landing simu lator), the only customer to be announced is Heinkel, whose 211-B1 is based upon two CF-700s in the extreme tail, the intakes for the engines and fans being in the leading edges of the butterfly tail and around the entire rear fuselage, respectively. The projected SF140 would have a zero stage and give 4,8001b. CJ610 A civil derivative of the J85, the CJ610 is now entering limited production in two forms: CJ610-1, 2,8501b thrust, 845,000; and CJ610-2B, 2,4001b, $40,000. The first signed contract for pro duction concerns the higher-thrust version, of which 100 were bought in January to power Aero Commander 1121s. Type certification came last December, and first delivery followed in April. CJ805 A commercial conversion of the J79, this engine was developed at Evendale as a complete powerplant with fail-safe reverser and "daisy" suppressor, and underwent exhaustive testing at company expense before entering service with the CV 880 in May 1960. Starting at l.OOOhr TBO, with sampling at 800, the 805-3 has advanced at the maximum rate allowed by the FAA, and TWA and Delta are being cleared to 2,000hr. The 805-3A and -3B incorporate numerous minor modifications, generally confined to blade rematching to allow a rise in turbine entry from 1,155 to 1,170°F together with attention to leakage to reduce consumption, and these engines power the CV 880M. A recent FAA airworthiness directive proposes revision to the reverser hydraulics to prevent asymmetry. CJ805-23 By adding a mechanically independent aft-fan unit behind the CJ805, GE produced an engine giving 50 per cent more thrust with 25 per cent better specific consumption. The fan is a single 48.8in wheel, incorporating 54 double-deck "bluckets" comprising an inner turbine blade working at 950°F and an outer fan portion at 200°F (these are metal temperatures). The fan is completely ducted, the cowling over it extending forward to the front of the pod on the CV 990, the only production application. Both engine and fan flows are diverted by a large clamshell reverser. The -23 first ran in 1957, entered service in October last year and is currently cleared to a TBO of 1,200hr. Minor improvements are incorporated in the engine now in service with . the 990, the -23B; the -23C is a variant tailored to the Caravelle 10A. The most serious trouble has been low-frequency fatigue in the fan, which in April led to an FAA airworthiness directive requiring blucket replacement after every 200 "operating cycles" (start-takeoff-shutdown). T58 When it first ran in 1955 the free-turbine T58 set a new stan dard for the 1,000 h.p. class, and no other engine has yet equalled its power/weight ratio or s.f.c. Key to its performance is the use of a relatively high-pressure axial compressor, which at the same time makes it fairly expensive to buy. About 830 have been shipped by the SAED at Lynn, mainly for the HSS-2, HU2K and Boeing Vertol 107 heli copters, but also for VTOL experimental machines. Some of the latter have propellers, although a true turboprop T58 does not exist outside the UK, where de Havilland make one as a version of the Gnome, q.v. The commercial CT58 costs $69,000 and is in regular service with NYA, CHA and LAA at an initial TBO of l,000hr. All CT58s are twin installations in 107-IIs and S-61Ls, and last month the FAA approved the CT58-110 to be run at take-off power for up to 30min. This special contingency rating eliminates the need to overhaul any engine exceeding normal power more than 5min and also offers benefits in safety and payload. Total T58 and CT58 time is 115,000hr, of which 65,000 is flight time. T64 Although only bought in prototype quantity, the T64 family is expected to play a major part in V/STOL aircraft of the next decade. Initially rated at some 2,800 s.h.p., the engine has so high a pressure ratio that it can compete with piston engines on a fuel-cost basis, and has an outstanding brochure performance (handsomely exceeded on test) despite the fact that it is quite conservatively designed in other respects. The Navy has put some $60m into the design, test and quali fication—including 10,000hr testing—of the T64-6 direct-drive 13,600 r.p.m. unit, the T64-2 5,200 r.p.m. turboshaft, and the T64-4 and -8 turboprops which have 1,160 r.p.m. prop shafts mounted respectively below and above the engine axis. Since most difficulty has been met with the turboprop gearbox, which has had to be redesigned in a strengthened form adding 561b to the weight, GE have concentrated upon this version in the flight-test programme, and have achieved satisfactory results with engines flying in a Caribou at Downsview since September. General Electric J85-5
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