Ideas on
Page 59
Page 58
Page 60
Page 61
Page 62
If you've noticed an error in this article please click here to report it so we can fix it.
Ai
Lispension
Italian ( New TJ Extend vehicle Manufacturers Develop Springing : Larger Makers to Increase Potential Markets
An F. Moon, A.M.I.R.T.E. T_HERE is ample evidence at this year's Turin international Motor Show—the 10th since the war and the 40th in the series—that the Italian commercialvehicle industry is becoming well established in the forefront of European design techniques, preceded only by Britain and Germany. The -Show, which was opened on November 5 in the presence of the President of the Italian Republic, Sig. Giovanni Gronchi, and closes next Sunday, contains a greater number of exhibits than before.
Reporting on last year's Show, I paid particular attention to the Ceat and Pirelli-Saga air springs, which were seen on the respective stands of these tyre manufacturers and were fitted experimentally to a few of the exhibits. Fiat were known at the time to be experimenting with these springs, particularly the Saga Elipress type.
This year Fiat announce one new passenger chassis,, and a derivation of an existing one, which are available with Saga Elipress air suspension. There is no question of these being experimental applications, because I "visited the Fiat_ commercial-vehicle works and saw these chassis coming off the production line.
Ceat rolling-lobe air springs are used in conjunction With Fiatrunning gear :in , two niakei of Integral coach—the Menarini Monocar and an S.C.A.L.L.'design. Both these vehicles incorporate Fiat 306/2 -mechanical units and the S.C.A.L.L. is interesting for its use of combined semielliptic and air. suspension at both .axles.
Air suspension is a feature. also of the new Latta Fraschini underfloor-engined passenger chassis which. B24 together with an 8-ton truck, comprises the first commercial vehicle (other than one prototype which was never put into production) to have been built by this concern since their merger with Breda at the end of the war. From the look of these two exhibits, it would seem obvious that Isotta Fraschini are determined to re-enter the market as far ahead of the more established manufacturers as possible, because their new passenger chassis incorporates several advanced features.
Viberti, who last year exhibited applications of Ceat air springs and the interesting Pogioli plastics suspension, do not appear to have undertaken much development work with either of these two systems. The only air-sprung Viberti vehicle is an articulated bus in one of the outside parks, which is equipped with Ceat springs.
Other new models to be seen at Turin include several Fiat trucks of 5-, 6and 8-ton capacity and a lightweight underfloorengined passenger chassis based on 4-ton truck units. The Lancia heavy-duty 4 x 4, medium-duty Esadelta and the multipurpose Jolly 1-ton chassis are also new, O.M. break fresh ground with the Tigre S rear-engined passenger chassis with a new supercharged engine, the supercharger of which can be engaged or disconnected at will. Viberti 180 VF 4 x 4 tractor and dumper chassis are other new products.
A demand by Italian coach operators for air suspension is made fairly obvious by the number of pasSenger-vehicle exhibits so equipped and this tendency was confirmed to me by one of the Fiat engineers. A possible incentive towards the rapid adoption of air-sprung coaches is the large number of American tourists who tour Italy by coach each year. Indeed, several of the bodywork exhibits based on conventional chassis were intended solely for carrying American visitors and, as most Americans are by now fully aware of the advantages of air suspension, it is only to be expected that they should demand such high standards in countries which they may visit. 'This demand will most probably materialize in Great Britain also before much longer.
The Fiat air-suspension system is possibly unique in its use
as standard of the Saga Elipress spring. This was fully described in The Commercial Motor on December 27, 1957. It consists essentially of a light coil spring embedded in the walls of a helically contoured rubber cylinder. The principle is that the unladen weight of the vehicle is supported by the coil springs and additional weight is accommodated by admitting air into the cylinder.
Once air has been admitted, the springs act like normal air units, but when the vehicle is empty they are not in circuit with the rest of the air-pressure system and, indeed, cannot be brought into circuit until the driver has pressed a button on the instrument panel. When the vehicle is travelling completely empty. it has solely coil-spring suspension with slight rubber damping. This in turn allows the use of quick-acting levelling valves which will react smoothly under full load, but would cause harsh suspension characteristics when running unladen if they were in circuit under such conditions.
In the case of the 306/2 application, the existing chassis frame has been retained and has been modified only to the extent of having radius-arm brackets and supplementary crossmembers. The front suspension consists of four radius arms, two below the axle and two above, and four Elipress springs, one ahead of and one behind the axle on each side. Two telescopic dampers and two Magneti Marelli levelling valves are employed and transverse axle location is given by a conventional Panhard rod. The axle beam is a standard Fiat assembly.
A similar sort of layout. has been employed at the rear axle, using the same number of rods, springs, dampers and levelling valves, which gives a desirable degree of standardization between the front and rear suspension components. Because
a26
of the location of the springs relative to the axles, all vertical loadings are directly absorbed by the,springs and there is little tendency for road shocks to be transmitted through the radius arms to the frame and hence to the body.
The new Fiat 309 chassis also is available with this Elipress air suspension and, like the 306/2 chassis, is an underfloorengined design, the principal difference between the two types being in respect of size. • Whereas the 306 model has a wheelbase of 18 ft. 5 in. and an overall length of 35 ft. 6 in., the 309 has a wheelbase of 15 ft. and an overall length of 27 ft. 4 in,
Even smaller is another new Fiat passenger chassis—the 314. This has a wheelbase of 12 ft. 4 in. and an overall chassis length of 22 ft., but, like the larger models, it is an underfloorengined design, although air suspension is not offered. The
314, which is suitable for bodies with up to 40 seats (including gangway seats), uses the mechanical components of the C 40 N normal-control 4-tonner, the 4.6-litre 90-b.h.p. engine of which has been modified for horizontal mounting. • Like the 4-ton chassis, the 314 has, a five-speed synchromesh gearbox. Suspension is by semi-elliptic-springs with telescopic dampers at both axles and the chassis is rated for a gross vehicle weight of 8 tons. It' therefore has no direct British equivalent, .for our on chassis of this weight rating are longer.
Of the' several new Fiat goods vehicles, the smallest is the -C 50 N normal-control 5-tonner, which is essentially an uprated version of the C 40 N 4-tanner introduced last year. The principal differences arc in respect of springs-and tyres.
Of slightly heavier capacity are the new 642/N6 and 642/N6R fOrWard-control 6-tonners, which have a similar cab to that of 'the larger Fiat forward-control vehicles. The heaviest new Fiat goods chassis is the 6821N, which is rated for a solo weight of 81 tons and has a 200 b.h.p. turbocharged engine, which normally develops 150 b.h.p. without turbocharger.
Thus the present Fiat goods range now extends from the 1-ton forward-control models introduced last year to maximum capacity tractors with engines of up to 200 b.h.p, It is significant that because of the low cost of oil fuel in Italy, all these vehicles, except for the 1-tonners, have oil engines. This trend is general throughout Italy.
Next to the Fiat exhibits in order of importance and interest are the new Isotta Fraschini models. The more advanced of these is the D 160 A underfloor-engined passenger chassis. The essential features of this design include a six-cylindered directinjection 10-litre horizontal oil engine which, with turbocharger, develops 185 b.h.p. at 2,000 r.p.m. This is unitmounted at three points over a Z.F. Hydromedia automatic gearbox. A novel feature of the engine installation is the use of a thermostatically controlled hydraulic fan drive--a valuable power-saving feature.
A two-piece propeller shaft takes the drive from the gearbox to the heavy double-reduction rear axle and at the centre bearing there is a drum transmission brake. Z.F. hydraulically assisted steering is employed and the chassis frame, which is notable for its clean layout and flat top flanges, is welded, with a maximum side-member depth of 9 in. and with channel reinforcement over the engine.
The air suspension employed is of interest, because of its simplicity. At the front a conventional beam axle is rigidly mounted to rear-pivoted radius arms, with lateral location by a Panhard rod. Two Firestone double-convolution bellows units are employed, these being made under licence in Italy by Pirelli-Saga. The springs are immediately above the axle beam. There is a levelling valve controlling each spring and ahead of the axle beam there are two rather small telescopic dampers, whilst inboard of the springs are robust rebound check rods.
Simplicity in the rear suspension is derived from the use of light semi-elliptic springs to provide axle location and torque reaction. additional reaction being given by radius rods pivoted to the top of the axle tubes. Four bellows units are carried on long square-section beams, which are located outside the semi-elliptic springs. Beyond the bellows at front and rear are telescopic dampers, and a levelling valve controls each side of the rear suspension system. The rear layout in particular shows much originality of thought, and subsequent development should reveal it to be as effective as certain more elaborate systems.
The new goods chassis introduced at the same time by Isotta Fraschini employs several common units, including a vertical version of the bus power unit (but without turbocharger), its rating being 155 b.h.p. A Z.F. S8160 eight-speed synchromesh gearbox, with air-assisted change, is employed, and the rear axle is similar to that on the passenger chassis. A hydraulic steering servo is incorporated and the chassis, known as the D 160, is rated for 14 tons solo weight, giving a payload capacity of about 8i tons. It is seen with a Borsani forward-control cab with sleeping bunk.
The most impressive Lancia exhibit is the new 506 4 x 4, which has obviously been produced with the object of interesting the military authorities. One of the more unusual features of ,this design is the use of a 6.78-litre six-cylindered petrol engine mounted beneath the cab floor at an angle of 30° to the horizontal. This unit produces 170 b.h.p. at 3,000 r.p.m., although another version is to be made with a 195 b.h.p. output for greater speed.
Double-reduction axles are employed at front and rear, and the main 'gearbox is unit-mounted with the auxiliary and transfer gearbox amidships. Conventional semi-elliptic springs are used and, carrying its full cross-country load of 5 tons, the 506 is claimed to be able to ascend a 1-in-2 gradient.
In common with Fiat, Lancia are extending into the mediumcapacity goods range and an example of this is the Esadelta 5-77tortner. It is unusual, for an Italian vehicle, in having a two-speed axle. The 8.25-litre six-eylindered oil engine develops 115 b.h.p. at 1,800 r.p.m. A maximum speed of 42 m.p.h. is claimed, together with a gradient ability of 1 in 31.
The smallest addition to the Lancia range is the Jolly—a forward-control 1-tonner with Appia engine and running units. The Jolly is a similar type of vehicle to the Fiat 1-tonners. In appearance it is generally similar to the British B.M.C. and Thames 15-cwt. models and it is suitable for use as a van, pick-up, bus or ambulance. The short. gear lever mounted on the top of the engine cowl, close /o the steering wheel, obviously gives a more direct action than a conventional steering-column gear change.
Most interesting of the O.M. exhibits is the Tigre S. which. like the larger Super Orione passenger chassis, is a rear-engined design with a-wheelbase of 16 ft. 3 in. and is suitable for 33-ft. bodywork. Its unique feature, however, is the use of a fourcylindered four-stroke oil engine with an P.M.-designed supercharger. This raises the output of the engine from 105 b.h.p. to 135 b.h.p. and the supercharger can be connected or disconnected at will by the driver, so that it need not be used except when road conditions demand extra power.
The helical-lobe supercharger is controlled eleetropneumatically, being driven from the engine timing gears by a small hydraulic coupling with a dog clutch. In addition to increasing the horse-power, the supercharger raises the torque output of this 6.8-litre unit from 305 lb.-ft. to 400 lb.-ft. The engine is mounted longitudinally at the rear of the frame and to reduce the rear overhang the radiator is mounted transversely alongside it, resulting in some lengthy belt drives to the fan.
Viberti, who at recent Shows have always provided the main mechanical interest, have a fairly orthodox collection of exhibits this year. Interest is centred upon the 180 VF 4 x 4 dumper and tractor chassis. This has. an O.M. 180 b.h.p.. oil engine and both the driving axles are robust double-reduction units. The suspension at the rear consists of short semi-elliptic springs, free to slide at both ends, with axle location by radius arms and trunnions. It is not clear what the payload rating of this new chassis is, but the dumper exhibit had a body of some 9or 10-cm-yd, capacity.
The air-sprung articulated bus exhibit shown by Viberti employs Fiat 306/2 mechanical units and is similar to other Viberti vehicles of this type. In the smaller field, Viberti are building integral vans with side sliding doors and Lancia Jolly running units.
H29 Among the body exhibits, the two most interesting are integral vehicles incorporating air suspension. Of these, the Menarini Monocar is the more conventional, the basic design being some 18 months old, although the exhibit is the first one to have been fitted with air springs.
The Monocar employs Fiat 306/2 running gear but, unlike the original Fiat chassis, has Ceat air springs. The front axle is located by a Panhard rod and two pairs of parallel-link radius arms and there are four air springs. At the rear the axle is carried on two long beams, each of which has an air spring at its outer ends. The layout is similar to that employed on the Guy air-sprung chassis. The Menarini Monocar has an unladen weight of 7 tons and the exhibit has 61 seats.
More unconventional is the S.C.A.L.L. 51-seat integral design. This also uses Fiat 306/2 running 'units, but stainless steel has been employed extensively in the construction, and the suspension layout embodies Saga Torpress bellows-type.air springs working in conjunction with light leaf springs which provide the axle location.
Unusual body features include the two three-piece doors, which have extremely large glass Panels and only slender supporting frames, and full air-conditioning equipment.
Italian coach styling generally has stepped up appreciably over the past few years and the use of chromium plating and • polished aluminium is now kept to a minimum. Despite this —or because of it—some most pleasing frontal stylings are to be seen at Turin, making a welcome contrast with some of the more flamboyant front ends to be seen in other parts of Europe, including Britain.
Macchi, who make German Bussing buses under licence in Italy, show front and rear air-suspension units which they will, presumably, be offering on future designs. These have been imported from Germany for the Show and, although the rear suspension is similar to that seen at Frankfurt in 1957, the front system is now of a similar layout to that used at the rear, consisting of long beams with an air spring on each end. The original Bussing front suspension with air springs had radius arms, and springs mounted directly above the axle beam.
Among the trailer, exhibits, Bartoletti show two unusual trailers in which the suspension consists of semi-elliptic springs with Firestone Airide bellows-type air springs replacing the rear shackles. The point of this installation is a little vague, except that possibly the air springs provide all the suspension when the trailer is running unladen.
Adige show a trailer with an experimental suspension system which is presumably the cylindrical type that they exhibited last year. Zorti have a 91-ton four-wheeled drawbar trailer with Neidhart torsional rubber suspension, the wheels being carried on trailing arms in the manner of the Austin Gipsy layout. An unusual 24-ton low-loading trailer is exhibited by Bertoja. The 2-ft. 5-in.-wide outer sections of the deck can be expanded outwards by 1 ft. on each side to accommodate extrawide loads, the fully extended overall width being 10 ft,