FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1956
1956 - 0221.PDF
Capt. Raymond Waski (above left) is the 57th Squadron's engineer officer and test pilot and has over 1,000 hours on craft's engines can be lowered and swung out from their mountings with a cable and winch (as shown above right), s< other parts can be reached without unshipping the engine entirely. Scorpions. The air- so that flame cans or The Black Knights of Keflavik laid on every possible facility, including some excellent weather,that rare Icelandic commodity, and the glacier of Myrdalsjokull. It is just as forbidding as its name. Flying the T-33 with ourcameraman who had been fitted for the occasion with a splendid scarlet hard hat, was Capt. R. Palumbo. Leading the formationof three F-89s was Lt. H. A. Chapman with Capt. Zeagler as observer, while Lts. A. H. Uhalt and D. A. Vogt flew in Nos. 2and three positions. In their rear cockpits were Lt. G. R. Wharton (a new pilot having a check ride) and Lt. D. J. Chaney.They all tore off to the glacier of the unpronouncable name and there followed McLaren's instructions to allow him to obtainthe fine photographs published here. I retired meanwhile to the pleasantly warm maintenancehangar and talked to Capt. Waski and the Northrop technical representative about the Scorpion. Many jokes are cracked aboutthis aircraft, and it has a number of curious nicknames, though none of these has stuck as the name "Gooney Bird" has to theDakota. This is probably because the 89 has not seen service in large numbers and is a quite straightforward machine. Fromsome angles, however, it looks ungainly and some people assert that the mainwheels were taken from some of the older loco-motives of the Atchison, Topeka and Santa Fe railway. It weighs 37,000 lb all-up, has a wing-span of 57.8 ft, and ispowered by two Allison J35-A-37 engines, each fitted with a high-altitude afterburner. At 14,800 lb the maximum staticthrust available is not high, so it is standard practice to use the afterburners at take-off. Without them, the ground run is con-siderably increased. But, considering the F-89's size and date of design, its per-formance is quite sprightly. The service ceiling is something over 40,000ft, which height is quickly reached. The airbrakesare in the form of split ailerons, called decelerons, which for braking power might be the envy of the pilot of many anotherjet aircraft. In the compressibility zone, they also have an ex- cellent stabilizing effect. The 89 is a big aircraft by any standard and everything on itseems to be big, except the engines. Much more powerful units have, in fact, been experimentally installed in individual aircraftand have proved successful, but the original contract stipulated the J35; and even the F-89D, which is several thousand poundsheavier than the C, will soldier on with the 7,400 lb maximum thrust of that engine. The outboard mountings have been arrangedas swinging drag-links which can be quickly released so that each engine can be swung some way downwards and outboard on acable-and-winch installation controlled by a hydraulic hand-pump in the rear cockpit. Access for maintenance is therefore veryeasy and the "hot parts" can be pulled for the 100-hour over- haul without completely unshipping the engine. The cockpits are pressurized and air-conditioned to a differentialof 5 lb/sq in for normal flights and 2.75 lb/sq in for combat situations. Temperature is thermostatically controlled, so thatvarious parts of the ram-air heat-exchanger and cooling turbine installation in the after-fuselage are cut out as more and moreheat is called for from the charge air which is taken from the eleventh stage of the port engine compressor. The forward radarcompartment is pressurized by a separate system but is neither heated nor cooled. Wing and tail leading edges can also be pro-vided with hot-air de-icing from bleeds at the eleventh stage ot both engine compressors, the air being afterwards dumped over-board. In addition, the engine intake cone and inlet guide vanes are provided with ice protection. As can be expected on a radar-equipped aircraft, the electrical system of the F-89 is extensive. Each engine carries a 28v D.C.generator and a 120v generator, the latter serving the radar. There is a 5,000vA, 400-cycle, 115v, single-phase inverter for the radar,with a l,500vA spare inverter working from the 28v supply. Two 500vA, 400-cycle, 115v, three-phase inverters provide a supplyfor instruments and other services. Panels on the nose can be removed to give access to most of the radar equipment, and theradar central can be wound up out of its compartment by a worm- screw gear located there. The scanner is mounted behind a com-paratively small radome in the extreme nose. The armament of the F-89C consists of six 20mm cannonteiredin the sides of the nose, and all links and cases are collected in chambers underneath the installation. The aircraft is also fittedfor 16 HVAR air-to-ground rockets on eight rails under the wings, but this armament is unlikely to be carried. The latest F-89 is arocket-firing intercepter and has greatly enlarged wing-tip pods housing Mighty Mouse rockets in their forward sections, the aftersections being retained as 300-gal fuel tanks. There is provision for an autopilot, but none was fitted at the time of our visit. Whilethe early 89 has the E-l fire-control system, the latest mark has the E-5 control and E-l 1 autopilot which combine to allow auto-matic collision-course interception. Later still the F-89 will be fitted to carry three Hughes Falcon guided missiles under eachwing. Fuel capacity is quite large, as befits an aircraft of this size.Called sump tanks, and each holding 101 U.S. gal, two fuselage tanks feed directly to the engines, and two further tanks in eachwing, called auxiliary 1 and 2, hold 107 and 267 gal respec- tively, while the tip tanks hold 304 gal each. This brings thetotal capacity to approximately 1,540 U.S. gal. The latest F-89 carries a further 300-gal tank in the fuselage nose, replacing theguns which are deleted in favour of rockets. It is noteworthy that the Scorpion carries no less than 900 lb ofballast in the extreme nose, just behind the radar aerial compart- ment; and even with the extra tank there, this ballast is retainedin the rocket-armed version. It acts on a moment arm of some 200 inches from the e.g. Fuel control is quite simple, from acontrol panel on the left-hand console of the cockpit. The pilot normally selects "all tanks," after which fuel is automaticallypassed from one tank to the other until it reaches the sump tanks; otherwise he can select each tank individually and cross-feed ifnecessary. Fuel quantity is measured by capacitance gauges in pounds. The tip tanks are not jettisonablc, but their fuel can bequickly dumped in emergency. This also applies with the enlarged rocket-pack tanks of the latest F-89, but this versioncarries yet further fuel in two 300-gal under-wing pylon tanks. These are jettisonable since the attachments are also designedto accommodate bombs or further rocket pods. The average sortie time of the early types of F-89 is aboutone-and-a-quarter hours, but the additional 900 gal now to be carried should increase this period quite considerably. The lateraircraft will also have single-point pressure refuelling to shorten turn-round times.The Scorpion is something of a monster even in its hydraulic system, though it seems that the hydraulic power source is notquite up to the demands of the services when these are all oper- ated together. Each engine carries a multi-piston, variable swash-plate hydraulic pump with a maximum delivery pressure of 3,000 lb/sq in; at 80 per cent r.p.m. the flow is 6.95 gal/min at2,600 lb/sq in. The port pump supplies power for one half of the flying controls and the utilities, while the starboard enginesupplies the other half of the controls. Undercarriage, wheel- brakes, flaps and decelerons are hydraulic, with a bungee-and-gravity standby for the undercarriage, compressed-air emergency
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
