FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1948
1948 - 0465.PDF
APRIL 8TH, 1948 FLIGHT 393 Speed Recording variation. Any heading other than that which is perpendicularto the direction of the two beams will result in flying a longer, course than that for which the speed is computed. Computedspeeds will be lower than actual speed, and will vary with heading as follows:— HEADING VARIATION ERROR IN COMPUTED SPEED 1 deg 0.015 per cent2 deg O.061 per cent 3 deg 0.137 per cent4 deg 0.244 per cent 5 deg 0.381 per centDistance between the two beams has been determined by a Coast and Geodetic survey which is accurate to one part in onemillion. Because of curvature of the e$irth, the two beams are not parallel, but spread apart slightly as a function of altitudeand beam separation. On the basis of a 10-mile beam separa- tion, this spread with altitude amounts to 151ft at. a height ol60,000ft. The beams are aligned and maintained to within ±5oft at a distance of 12.5 miles from the transmitter. Onthe basis of a course-run of 10 miles, and both beams off the maximum amount in opposite directions, this error amountsto 0.190 per cent. The error introduced by chronograph timing is ±0.008 second. On the basis of a speed of 600 rn.p.h. and acourse-run of 10 miles, this error is 0.0133 per cent, which is negligible. Using maximum errors that can be reasonablyassumed, such as 3 deg variation in heading, beam alignment in error by 100ft (two beams off in opposite directions) and a0.008 second timing error, the maximum error on a basis of 600 m.p.h; and a run of 10 miles is 0.34 per cent. The probableerror is less. The all-altitude speed course is now in operation in thevicinity of Wright Field, and a second installation is scheduled for Muroc Army Airfield, California. These facilities are to beavailable to all branches of the armed services as well as in- stitution activities, such as the N.A.C.A. iv\ THE \OIUI 1700 NORELIC French Helicopter with Unusual Features THE S.N.C.A. du Nord, in common with other sections ofthe French nationalized aircraft industry, has a number of interesting aircraft in project and prototype stages. Theconcern has recently completed a helicopter known as the Nord 1700 Norelic, which is at present undergoing flight tests. Thefirst flight of the Norelic was jnade on November 17th at Issy- 77ie research prototype of the Norelic helicopter. les-Moulineaux, and the helicopter is of single two-bladedmain rotor configuration, with a small auxiliary rotor. An unusual feature of the design is that it incorporates a pusherpropeller running in a guide cowling or shroud. This feature, in addition to providing some forward propulsion, is claimedto counteract torque reaction by means of its airflow effect on a series of large tail fins or vanes attached to theshroud. The shroud eliminates the risk of injuries sustained by persons inadvertently walking intothe rotating propeller. Construction is of all- metal monocoque type, and the Norelic providesside-by-side seating for two persons. The first prototype, depicted in the accompany-ing photograph, is intended primarily for research purposes in determining the features desirable forthe subsequent production model. The cockpit enclosure ot the prototype will eventually bereplaced by one of cleaner design, and somewhat reminiscent of that of the Bell Model 47; and thecomplicated rotor head will be enclosed in a neat fairing. The manufacturers claim that in the eventof an engine failure, and the subsequent disconnection of the power transmission, theNorelic offers a considerably lower sinking speed than many contemporary types. The estimatedperformance of the Norelic when powered by a Mathis G7R engine developing 160 h.p. at 3,1001.p.m. is: Maximum speed, 115 m.p.h.; cruising speed at 75 per cent power, 96.3 m.p.h.; maxi-mum rate of climb, 1,056 ft/min; range, 248.6 miles; maximum hovering ceiling, 5,000ft; maxi-mum ceiling, 9,842ft. AMERICAN AIRCRAFT GAS TURBINES i'T is frequently stated that this country is well ahead of all•»- others, including the United States, in the development and production of aircraft gas turbines. We believe this to be true,and facts recently published in America, the only country which offers important competition in this field, seem to confirm thestatement. In a recent review of the gas turbine position in America,our contemporary, Aviation Week, points out that the two major producers of military engines for World War II are notturning out jet engines for service. These companies, the Pratt and Whitney Aircraft Division of United Aircraft Corp.and Wright Aeronautical subsidiary of Curtiss Wright Corp., were not in on the early development of jet engines becauseall of their engineering and manufacturing facilities were devoted to piston engines. It seems that they are now spend-ing about 30,000,000 dollars in an effort to catch up on jet development. The only company which now have jet enginesia quantity production is the Allison Division of General Motors Corp., and their production engines were originally developedby the General Electric Company, a non-aviation concern. About this time last year Pratt and Whitney began toolingup for the production of the Rolls-Royce Nene, following a remarkably successful passing of the U.S. Navy's 150-hour typetest by one of these units. An important new Navy fighter, the Grumman XF9F-2, is now flying with a single Nene forpower. Reports on the behaviour of Nenes in America during the last year have been excellent. A word on definitions is also contained in Aviation Weeksuggesting that in addition to the family name of "gas tur- bine" the three more common varieties should be called"turbojet," "turboprop" and " turboramjet." A turboram- jet is a turbojet with after-burning. Manufacturer Allison Div. of General Motors General Electric Westinghouse Electric Model J-22-A-33 J-35-A-I5 T-3I-GE-3(TG-IOOB) J-30 (I9X&-2B) Type C A AP A Compres- sor Stages 1 II 14 10 Turbine Stages 1 1 1 1 Thrust Ib SX. static 4,600 3,750 500 1,603 s.h.p. — 1,900 — r.p.m. 11,750 7,700 13,000 17,000 Spec, fuel consurnpfc. Ib hr Ib thrust 1.12* 1.075* 0.768 1.15 Overall length (in) 103 145 114.5 94 Overalldiam. (in) 50.5 37.5 35 19 Weight Ib 1 1,735 2,425 1,984 718 * At Cruising power
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
