Allan Winn/Bristol - Bremen
FOR 26 YEARS, THE JOKE was that every Airbus had its first flight on a Boeing wing - as a collection of components carried in one of the consortium's Super Guppy outsize transporters. (It was not strictly true - the first two A300s did not, and since 1996 an increasing number of components have been flown on the new-generation Airbus A300-600ST Beluga.) Nevertheless, the history of Airbus is linked with that of the Super Guppy, which has in effect been the string which tied the production plants of the partner companies together.
It is a part of history which came to an end on 24 October, when Airbus' remaining Super Guppy made its final flight, from Toulouse to Bristol, then Bremen and on to its final resting place at Daimler-Benz Aerospace's (Dasa's) Finkenwerder plant at Hamburg. Flight International was invited to join the Bristol-Bremen leg of this historic flight, to sample a unique style of flying for the last time.
The Super Guppy was developed by Aero Spacelines of Van Nuys, California, around the Boeing Model 377 (C-97 Stratocruiser) airframe, originally as a means of transporting rocket stages for NASA's Apollo space programme. In essence, the top of the Stratocruiser's "double-bubble" fuselage was chopped off and a new, larger-diameter top bubble installed. In practice, it was a lot more complicated than that. By cannibalising several C-97 airframes to build each Super Guppy, extra fuselage and wing sections were added to lengthen the fuselage by 10.2m (33.4ft) and the span by 4.6m. The new upper fuselage had a maximum floor length of 34m, of which 9.75m were in an area of constant cross-section with an internal width and height of 7.62m. The forward part of the fuselage was separated, just behind the cockpit, and arranged to hinge so that, with some effort, it could be swung to one side to allow large loads to be slid into the cargo area.
PRESSURE BULKHEAD
The hinged forward part of the fuselage was given a new pressure bulkhead (incorporating an access door into the cargo area which, naturally, could only be opened while the aircraft was depressurised), enabling the cockpit and the lower forward part of the fuselage to be pressurised. The original 2,425kW (3,250hp) Pratt & Whitney R4360 Wasp Major 28-cylinder piston engines were replaced by Allison T501-D22C turboprops, each delivering 3,665kW.
Airbus Industrie eventually operated four Super Guppies, employing them to move major components of the Airbus range of airliners between the factories of its four partners. Originally, the aircraft were flown by Aeromaritime (part of UTA) crews and maintained by UTA, but since 1989 the Super Guppies have been crewed and operated by Airbus itself.
The first two Super Guppies (377-SGT-201 and 202) were built by Aero Spacelines at Santa Barbara, being delivered to Airbus in 1971 and 1973 respectively. Airbus later found that it needed more than two such aircraft, and arranged for UTA to build two more under licence to Tracor Aviation (as Aero Spacelines had become) at Le Bourget in Paris. These latter aircraft, redesignated 377-SGT-Fs, were delivered in 1982 and 1983 respectively: in 1982Airbus negotiated the right to build a third 377-SGT-F, but this (which would have brought the fleet to five) was never converted.
In the 26 years for which they served Airbus, the four Super Guppies amassed a total of 47,150h flying time, and carried almost 100,000t of components around Europe.
First impressions on approaching a Super Guppy now are of how short the aircraft seems compared to modern large transporters, yet how imposing it is when seen from the front. Crew access is via a swing-down door/stair low on the right-hand side of the aircraft just behind the nosewheel. This leads into a lower compartment from which a vertical ladder leads up through a trapdoor into the flightdeck.
SPACE AND LIGHT
The overwhelming first impression of the flightdeck is one of spaciousness and light. It is lit by no fewer than 13 large transparencies on two tiers, with a further two eyebrow windows which are blanked off by padded covers. The lower tier of transparencies is at knee level to the seated crew, affording them a superb view downwards to the front and to each side.
The crew itself has a vast amount of room in which to work. The captain and first officer sit well inboard of the sides of the fuselage, with access to their seats being around the outside rather than through the centre. On the left, just behind the captain's left shoulder, is a jumpseat which resembles more than anything a revolving, metal typist's chair. There is a similar space on the right-hand side in which another jumpseat could be installed. Behind and above the two pilots sits the flight engineer, with a large console carrying the major propulsion controls in front of him, and the major engine instrumentation on a vertical panel to his right.
Behind this spacious area in the Guppy is a further crew area, arranged in a "club-four" layout of airline seats each side of a large table. Behind the captain is a shelf for a very 1940s electric water-boiler - the in-flight catering.
While the flying controls are pure Stratocruiser, the flight- and engine-instrumentation reflect the mid-life conversion which the aircraft underwent - and where it underwent it. As one of the UTA-converted aircraft, the final Super Guppy, F-GDSG, has flight instruments specified for the Sud Aviation Caravelle, while the engine instruments are all specific to the old-style Allison T501 turboprop (complete with engine torques measured in thousands of lb-in, for instance). The flying-instrument panel is deeply cowled to shield the instrument faces from reflections of light from the large area of glazing: to render them readable, they are front-lit by a most agreeable pale-blue light.
The other controls form a reminder of the era in which the Stratocruiser and its B-29 forebear were designed. Above the captain's head is a massive red lever for locking the control surfaces. To his left, mounted vertically on a pedestal which looks like it was stolen from a motor launch, is the full-circumference nose-steering wheel, with its engage-disengage lever below.
The stretched wing is a long way back on the similarly stretched fuselage: from either of the pilots' seats only the outer engine and wingtip are visible on that side. Looking upward and outward from his seat, a pilot can just see the start of the swelling of the bulbous fuselage above the original cockpit roof.
THE LAST FLIGHT
Engine starting is done through fuel and ignition switches mounted on an overhead panel: the immediate surprise as this takes place is how quiet the flightdeck is as all four propellers come up to speed. At idle (70% RPM) the big Allisons burn an indicated 295kg of fuel each, showing just 1,000lb-in at torque.
After a long taxi back down Filton's undulating runway, at last the big aircraft was turned: nose steering disengaged, and there was a deepening of note as power and prop levers were advanced. Progress, even at an all-up weight of 55,720kg with just over 9,500kg of fuel or just over 21t below the MTOW of 77,110kg, is best described as stately - more a gathering of speed than an acceleration until, at around 110kt, the ground started to drop away.
The initial surprise of quietness on the flightdeck was confirmed as the Super Guppy climbed away at 150kt (280km/h): propeller synchronisation would put most modern turboprops to shame, with not the slightest hint of a beat. By 6,000ft (1,800m), the aircraft was sustaining 185kt, and climbing at 1,500ft/min (7.62m/s), with the Allisons delivering 15,000 of their maximum 25,000lb-in of torque.
One thing becomes obvious as the Super Guppy climbs and speed starts to build: this bulbous craft is strictly Mach-limited. The placard on the instrument panel says it all: above 14,000ft, maximum allowed indicated airspeed drops by 4kt for every 1,000ft. At 6,000ft and 185kt, there was a healthy 35kt margin available; by 18,000ft there was only a 25kt margin above our 170kt speed; but at our final cruising altitude of 21,000ft, there was just a 5kt margin between the 180kt chosen and the 185kt limit.
Cruising at that altitude, the engines were sipping 500kg/h each, with torques back to 9,000lb-in. In the left-hand seat, pilot Daniel Tremosa demonstrates that even in today's computer-dominated skies, Super Guppy crews continue to track their fuel consumptions with quaintly named poids-air miles charts (which confirm flight engineer Gérard Le Gall's predictions of an average 2,270kg/h fuel use).
IN CONTROL
Then it is time for Flight International to borrow the right-hand seat from chief pilot and operations director Paul Urset. With the big, comfortable chair pulled forward and its height adjusted, all of the initial impressions of the superb view through the extensively glazed nose are confirmed. Straight ahead and to the right, both up and (especially) down, it must be a view unmatched in a large transport, with almost no nose forward of the windscreens (and none of it visible to the pilot). Even across the cockpit past the central instrument panel, the view is infinitely better than in many modern types.There are, however, no eyebrow windows above the main side windows, so visibility to the side in steeper turns is not great.
The Guppy was flown entirely manually throughout the flight, so it is just as well that, although the flying controls look ancient, they provide a surprisingly modern feel. The ailerons are high-geared, but light and very accurate, providing a quick and predictable response to even the smallest of inputs. Straightening the nose against a crosswind with rudder as we settled on to a new course showed that control to be heavy but, again, accurate and powerful. In pitch, there is greater inertia, perhaps accentuated by the presence of the large fuselage. The feel is there in the elevators, with no apparent lost motion, but the Guppy seems to take a couple of seconds to respond to a control input, so that the first few movements bring a fear of undamped pilot-induced oscillation. Pitch trim, via a large trim wheel alongside the seat, is extremely sensitive, with only the tiniest of adjustments sufficing. With all that mastered, however, the Guppy is an enjoyable machine to control - but not one to relax with, needing fairly constant inputs to maintain course, height and speed. Ah, yes, the speed. With that tiny margin between cruise speed and Vmo, there is no chance of nodding off as the clacker warning regularly intrudes on the quiet of the flightdeck.
With the professionals back in control, we began our descent into Bremen - the last stop before F-GDSG reached its final resting place at Finkenwerder. With the power levers back, and propeller pitch back to 50% from the cruise setting of 70%, fuel flows dropped to their idle figure of 318kg/h, and torques to a negligible 2,600lb-in, leading to a 2,000ft/min descent. The Guppy's Stratocruiser forebear was notorious for its nosewheel-first landings - which Tremosa says is the only method for getting the aircraft on to a short runway. On Bremen's adequate length, and with the Guppy empty, a more conventional attitude could be adopted for the final touchdown after a steep final approach.
Flight International left the aircraft there, with just one short hop to Hamburg left in its flying career - the last-ever flight by a Super Guppy in European airspace. Just one of the four Airbus Guppies is left flying: Number 4, the last to be converted, is back doing what the aircraft was originally created for - flying parts for NASA. This time, it is for the International Space Station. In Europe, the Guppies have been replaced by faster, bigger and twice-as-productive Belugas - and no more does an Airbus first take wing courtesy of a Boeing.
Source: Flight International
