FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1957
1957 - 1855.PDF
FLIGHT, 20 December 1957 FLYING THE CARAVELLE . . . 290 kt at 13,000ft, thereafter holding it at that figure up to cruising levels. Engine r.p.m. are held at 7,100 up to 30,000ft, then increased slightly (to 7,250) until the desired cruise alti- tude is attained. Initial rate of climb is about l,500ft/min (with a jet-pipe temperature of 580 deg C) and service ceiling is in the region of 42,000ft. Spiral stability is positive in both cruising and approach configurations. In approach and landing configuration the unaccelerated stalling speed at gross weight is about 90 kt, and one finds that a slight tendency to drop a wing can be easily counteracted by use of aileron. At all altitudes, and with any e.g. position, a slight reversal of stick forces occurs at approximately 100 kt. This is not caused by instability, but by airflow changes, and an automatic trimming device now counteracts it, so that the pilot is not aware of the effect. The trimmer is capable of cancelling-out stick forces at any e.g. position and airspeed. Trimming is accomplished by varying the datum position of the jack which applies artificial-feel loads to the control column. The control system [described in detail in Flight for May 27, 1955] is fully powered, with two independent hydraulic supplies; there is no means of reversion to manual control. Asymmetric power produces no yaw, because the thrust lines pass through the e.g., and no trimming is required to counteract yawing or rolling moments. By using the sensitive and effective trimmer it can be established that the Caravelle is longitudinally statically stable in all configurations and e.g. positions. A standard climb to 33,000ft covers 220 miles, takes 40 min and uses 4,400 lb of kerosine. Between 33,000 and 38,000ft, cruising speed at 7,250 r.p.m. settles at 390 kt with a fuel con- sumption of 4,400 lb/hr. At 32,000ft, cruising speed is 400 kt and fuel consumption 5,000 lb/hr. Maximum level speed at 20,000ft is 270 kt I.A.S.; and in this condition dynamic stability remains good, even with acceleration from 1.5 to 2 g. Decreased temperatures at the higher altitudes cause a slight control friction, but effectiveness is not lost and the stick continues to return to neutral even after being sharply dis- placed. The layout of the air-conditioning and pressurization system was described in detail in Flight for May 27, 1955. In practice one finds that the indicators and controls are well positioned and the system as a whole effective. Sea-level 945 A plan view which is likely to become symbolic of European short/ medium-range jet airliners in the years ahead. "Flight" photograph cabin pressure can be held up to 18,000ft, which allows the maximum rate of descent of 5,800ft/min to be used without causing discomfort to the passengers. A standard demand- regulator oxygen system is fitted for the crew; and the "blinker" indicators are well placed for easy observation when necessary. Pressurization, air-conditioning, anti-icing and fuel system are controlled from panels distributed around the co-pilot's seat. The highest Mach number reached during my test was 0.84 at between 35,000 and 40,000ft. The only compressibility effect was a slight buffeting which began at a Mach number of 0.82; and there were no pitching tendencies other than those caused by the normal changes in static stability follow- ing increase in speed. Airbrakes, which may be used at maximum Mach number and I.A.S., extend in three seconds but cause a certain amount of vibration. Reduction of power is also an effective way of reducing speed. Aileron effective- ness is maintained at all speeds and Mach numbers. A typical let-down from 38,000ft to 5,000ft is made without airbrakes at a constant 216 kt in 36 min, covering 150 miles and using 660 lb of fuel. Standard reserves permit 45 min holding at 10,000ft, a missed approach and a diversion of 150 miles, using 6,600 1b of fuel. During the approach and landing one finds that flap and undercarriage extension cause negligible trim changes, and the airbrakes remain very effective. The normal approach is made with power at 1.5VSL (135 kt). Small power-variations produce only small results, but a strongish ground effect in calm conditions distinctly assists the pilot in rounding out. In power-off approaches or strong winds this effect dis- appears. From the 4,500 r.p.m. approach setting, full power can be reached in five seconds and acceleration is then suffi- cient to re-establish safety speed very rapidly. With the tail braking parachute the landing run can be limited to 1,800ft; without it, at a weight of 86,000 lb and in standard atmos- phere, the ground run is 2,160ft. At 66,000 lb the run is reduced by 650ft. [A full structural description of the Caravelle, with cutaway drawing, first appeared in Flight for May 20, 1955. The electrical, control, fuel and air-conditioning systems were described in the following issue; and later information has been summarized in the issues of July 6, 1956, and November 1 this year.—Ed.] Tucked closely in to the centre-line, the Caravelle's Rolls-Royce RA.29s minimize the yawing effects of asymmetric power. Nosewheel-steering permits satisfactory ground-manoeuvrability.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
