The FIAT G.95 project

In the early 1960s, NATO put out a requirement for a supersonic V/STOL fighter-bomber. The requirement, NATO Military Basic Requirement (NMBR) 3, did not specify a technical solution to the problem of V/STOL, just the type of plane (fighter/bomber) and the capabilities (supersonic, VTOL). This wasn't the first NATO sponsored competition; the preceding NMBR-2 gave birth to the G.91, a successful plane in the role for which it was conceived, but the competition itself was not a success, as only Italy and Germany ended up buying it; other NATO members either ignored it or opted for other aircraft instead.

Before the NMBR-3 requirement was published, at FIAT, aircraft designer Giuseppe Gabrielli, was already at work for a G.91 successor; among the features of this aircraft, there was STOL capability. The plane, code named G.95, was similar to the G.91Y (a twin engine version of the G.91), with a pair of auxiliary jets located in the fuselage near the center of gravity and with the nozzles canted 45° downwards, providing both thrust and lift at the same time



When Fiat entered the NMBR-3 competition, Gabrielli altered the design to make it a true VTOL. The fuselage grew wider, the space between the two main engines and air ducts being occupied by four lift engines, two fore and two aft of the center of gravity and with fuel tanks in between them. This concept was code named G.95/3



To make it truly a supersonic design, however, more powerful engines were needed; these took more space, weighted more and, in turn, also the lift jets needed a boost. The result was a long and slender aircraft, with a very noticeable wasp waist and with a total of six lift jets (three fore, three aft) code named G.95-6 but also colloquially known as the 'Flying sausage'.





Neither this nor the other projects for NMBR-3 competition looked very promising. In fact the idea of obtaining a supersonic VTOL for NATO languished: Hawker will eventually build the Harrier, a subsonic design, while Dassault's Mirage IIIV did reach Mach 2 but, with eight lift jet engines, it was a nightmare to maintain, not to mention that the dead weight of these auxiliary engines meant that fuel and weapon load had to be reduced accordingly.

The story was not over for the G.95, because the Italian air force awarded FIAT a contract and funds to study a viable successor to the G.91 with V/STOL characteristics. It would have been a less ambitious plane, capable of only Mach 1.1-1.3 at maximum but still good enough, maybe, to pick the interest in other NATO countries. Gabrielli thus scrapped the design of the G.95-6 and went back to an early design with looked easier to implement, and that would have met all the requirements of the Italian air force: the G.95-4 This plane went back to use 'only' four lift jets, but they were located at the center of the fuselage. To validate the design, FIAT even built a 'flying test bed'





Unfortunately little progress was made after that. Since the idea of a supersonic VTOL was hard to die in certain NATO circles, FIAT then decided to join forces with German Focke Wulf and to work on another design, the VAK 191B, which, at last, was realized in 3 prototypes. Nothing came out of it or, rather, it should be said that the collaboration between FIAT and some German industries paved the way for the creation of an European consortium which realized the Tornado and later yet another European consortium which built the Eurofighter.

PS: Most of the pictures were taken from here: Sixties Superfighters: The Original JSF- the Italian V/STOL FIAT G.95 'Resistenza'

That was an interesting post. I never would have known about these v/stol designs. Thanks.

Of all the mentioned designs, only the Harrier went past the prototype stage. It may be an overlooked factor, but the Harrier is also the sole aircraft among the many VTOL designs which doesn't use additional lift jets and that is able to use all the thrust produced by the engine either for lift or for moving forward. Even the new F-35B has a large ducted fan for generating additional lift that becomes basically dead weight once it is airborne (and it also takes a lot of internal volume).

Interesting post, not read much about the Fiat G.95 design; thanks for sharing. To add to this very informative thread, a little bit of British V/STOL history in connection with NMBR-3...

msxyz said:

Of all the mentioned designs, only the Harrier went past the prototype stage.

Click to expand...

Just to clarify, the Harrier that went past the prototype stage was not offered as part of NMBR-3, the Harrier that went into RAF service was developed as a private venture from the P.1127 V/STOL testbed and was developed for military use as a formal replacement for the Hawker Hunter in RAF service. The Hawker Siddeley aircraft that was designed for NMBR-3 was the P.1154, which was originally going to be called the Harrier, but it was cancelled at the same time as the TSR.2 in early 1965. The P.1154 was to be a supersonic thrust-vectoring jet that was to be built in two separate variants, a single-seat low-level strike fighter for the RAF and a two-seat carrier-capable high altitude interceptor for the Royal Navy, but the two roles were quite divergent and neither party could make up their mind what they wanted for the project. After the RAF pulled out, the navy did so too and the project died. The navy bought F-4 Phantoms once the P.1154 was cancelled.

The P.1127 on display at the Science Museum in London, which was designed as a testbed to trial vectored thrust, initially for the P.1154 programme, but from which the Tripartite Kestrel and the Harrier originated. The P.1154 was going to be bigger than what became the Harrier, which in its GR.1 first production variant differed little from the P.1127 in size, but was a world away in complexity.

DSC_0193

A crappy photo of a model of the P.1154, this is in Royal Navy colours but it is the RAF single-seater in configuration. The Harrier inherited the P.1154's nav/attack system, the Ferranti INAS, the first fully pre-programmable nav/attack system that enabled a single pilot reading information from a moving map display and true HUD (the A-7 Corsair II had a similar set-up). The TSR.2 was also to be fitted with INAS, had it been put into production.

P.1154

The P.1154 was to achieve supersonic flight through plenum chamber burning (PCB, igniting the exhaust gases inside a plenum chamber) in its cold section nozzles, the two front ones, but problems arose over temperature control within the two separate nozzles, basically, the thing was put into the too hard basket. Here's pictures of the Bristol Siddeley BS.100 engine that was going to be installed in the P.1154, on display at the FAA Museum at Yeovilton.

BS100 i

The forward nozzles where the PCB was to take place are to the right. A Harrier was tested on a static rig fitted with PCB for a future supersonic STOVL test, but again, the concept was too difficult.

BS100 ii

The aircraft that 'won' the NBMR-3 specification was the Mirage III/V Balzac, seen here on display at the Musee de l'Air at Le Bourget, but this aircraft had its own issues. Note the jet-lift engine inlet doors above the fuselage.

Musee de l'Air 72

Aaaand, just for kicks, here's a picture of the Rolls-Royce RB.108 jet-lift engine fitted to the Mirage III/V, this one was fitted into a Gloster Meteor testbed behind the engine, at the Newark Air Museum.

NAM 69

Meteor FR.9 VZ608, the RB.108 testbed. This wasn't designed to actually achieve vertical flight but tested the thrust output of the engine.

NAM 87

These engines were also fitted to the Short SC.1, which was a direct lift pioneer research aircraft, which advanced the concept as pioneered by the Rolls-Royce Thrust Measuring Rig, the (in)famous 'Flying Bedstead' the first air breathing aircraft to carry out controllable flight using vertical downward thrust alone and fully controllable by vectoring thrust out the long pipes at the device's extremities, the same concept the Harrier uses to manoeuvre in the hover, only the 'puffer' nozzle controls are connected to the normal flight controls, simplifying the operation - the true genius of the Harrier. Here's the first TMR and the Short SC.1 on display at the Science Museum in London. The TMR was powered by two Rolls-Royce Nene engines, one of which can be seen at left. First flying in 1953, the TMR was designed around the theories of famous jet propulsion theorist Dr A. A. Griffith, who, back in the '20s and '30s had some extraordinarily complex and far-reaching ideas for gas turbine propulsion, many of which were truly far fetched and would not have worked in practise, but this one actually worked.

DSC_0167

The Short SC.1 mounted on the wall and missing a wing, I'm sure they could have displayed it better than this. Built by the Short Brothers factory at Queens Island, Belfast and first flying in 1957, the SC.1 was the first V/TOL aircraft to have a fly-by-wire control system, thrust from the lift engines to the rear horizontal flight engine was electrically signalled through the thrust lever in the cockpit, enabling a seamless transition from vertical to horizontal flight, which isn't as easy as it sounds.

Short SC.1

Four of the five RB.108 engines, which is probably why the jet is mounted on the wall, the fifth provided rearward thrust fed by the intake at left and exhausting out the rear, although it too was mounted inclined in the rear fuselage.

Short SC.1 lift engines

Oops, got a bit carried away...