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DUTCH WELCOME AIR SPRING NOVELTIES

EVER since the 1957 Frankfurt Show, air suspension has been the chief talking point at most European commercial-vehicle exhibitions, including, of course, last year's London Show. The 40th R.A.I. Show, which 6pened in Amsterdam last Friday and closes next Sunday, reveals a greater number of different suspension layouts than has probably ever been gathered under one roof. Air-suspension systems from Germany, Great Britain, Holland and Italy provide numerous contrasts in design, ranging from simple semi-trailer installations to strangely complex bus-chassis applications.

There is widespread enthusiasm among Dutch goods and passenger-vehicle operators for air suspension, so this Show gives plenty of encouragement for them, but the general feeling is that caution must be exercised at this stage, as many of the systems are undoubtedly untried experimental layouts which could prove unsatisfactory and unreliable. Nevertheless, semi-trailers with air suspension have already been sold in Holland in appreciable numbers, and are proving successful in many instances, leads having been established by D.A.F.—who exhibited an air-spring trailer at Frankfurt in 1957—and Netam, who have developed a conversion system for passenger vehicles also. This year's R.A.I. Show is expected to be the last in the present six-acre building, work having commenced on a larger establishment a little farther from the centre of Amsterdam. Of the 185 entries from 10 different countries. Britain and Germany head the non-Dutch vehicle exhibits, each being represented by 17 makes, with the U.S.A. having eight makes, France four, Eastern Germany three, Sweden two, and Italy, Austria and Switzerland one each. All told, there are 76 chassis, body and trailer makers represented, backed up by about 100 accessory and garage-equipment exhibitors.

The growing importance of the R.A.I. commercialvehicle exhibition is accerktuated again by the absence of a Brussels Show, this normally being the first Show in each year This, combined with the natural attraction of the Dutch markets for all European makers (stimulated by thoughts of a free-trade area) makes the Dutch Show

one of the most important exhibitions regularly held in Europe, the international flavour being more pronounced than at any of the other Shows. Over 102,000 people visited the last R.A.1. Show in 1957, and an even greater number is expected this year.

Despite the attraction provided by the air-suspension novelties, there is a great deal of interest in the more conventional exhibits, and a large number of the chassis shown has not been displayed in Holland previously. Of the British exhibits, all were seen in London last year other than a few specialized export models, these including

a normal-control Albion Reiver six-wheeled goods chassis; a Guy Warrior with Invincible Mark 11 cab, A.E.C. oil engine and a gross-train-weight rating of 25 tons; Austin and Morris 5and 7-ton chassis rated for 6and 8-ton payloads respectively; and a long-wheelbase Scammell 25-ton prime-mover with automatic coupling gear.

New Dutch exhibits include several D.A.F. chassis, trailers and engines; two Verheul goods chassis which result from the amalgamation of this body concern with the Kromhout chassis makers; Van Twist chassis assembled from Seddon components, some of which have Brockhouse automatic transmission; and a widely varied assortment of trailers, many with air suspension.

The D.A.F. concern is making great technical advances, and that this policy is paying off is shown by the sales figures for last month, D.A.F. sales accounting for 32 per cent. of the Dutch market, with Bedford second at 12 per cent.

An important innovation affecting the D.A.F. heavy-vehicle range is the introduction of the 1800 series of four-wheelers, developed principally for tractor use at 28 tons gross. The 1800 models have a turbo-charged version of the Leyland 0.350 oil engine which D.A.F. build under licence. The B.S.A. turboblower raises the gross power output from 120 b.h.p. to 165 b.h.p. at 2,400 r.p.m. and the torque peak from 275 lb.-ft. to 348 lb.-ft.

The D,A.F. 1500-series 7-tonners are replaced by the 1600series 8-tonners, these being available with either the D.A.F.built Leyland engine or a new 155 b.h.p. six-cylindered petrol engine. This petrol unit, together with a 135 b.h.p. version and a 100 b.h.p. oil engine, has a bore of 100.6 mm., which is standard throughout the whole D.A.F. engine range, allowing manufacture to be done by the same machine tools.

The 100 b.h.p. oil engine and the 135 b.h.p. engine are offered in the 1300-series goods chassis, which are rated at 10 tons gross weight, and the 13-series normal-control 91-ton-gross models. The previous versions of these chassis had either the Perkins P6 oil engine or the Hercules JXC 102 b.h.p. petrol engine, these two units now having been dropped by D.A.F.

Although two air-suspension systems are used on D.A.F. trailers, conventional suspension is retained on all their powered chassis, but this has been subject to recent modifications. The changes include the use of rubber inserts at the ends of the spring leaves, greasing points for dirt exclusion.at the sliding end of the springs, and rubber pads at the helper-spring brackets. A multi-pull hand brake has been introduced, and cab modifications include the use of a new front grille and a hinged switch panel on the dashboard which gives quick access to the fuses and wiring.

New D.A.F. Suspension

The D.A.F. trailer exhibits include a single-axle semi-trailer with independent air suspension, using General Tire and Rubber air pillows and anti-roll triangulated trailing arms in a similar layout to that employed on the tandem-axle suspension intro duced 18 months ago. .

The new Verheul goods chassis have attracted great interest, particularly in view of their stylish looks. These models are assembled by Verheul from Kromhout units and the range consists of normal-, semi-forwardand forward-control fourwheelers and semi-forwardand forward-control six-wheelers, gross ratings ranging from 25 to 38 tons in the case of tractor models, with payloads of 7+ to 15 tons for the load.carriers.

All the new chassis are powered by the Kromhout 140 b.h.p.

oil engine, and six-speed gearboxes are fitted. The chassis specifications generally follow conventional lines, but the cabs are of interest, the same basic cab being used on all chassis types, in the manner of the Guy Invincible Mark II cab. In all applications the cabs arz mounted high to give a level floor and small engine cowl, but this does nothing to assist access from ground level! Whatever their practicability, however, the cabs are certainly smart, as might be expected of a longestablished passenger-bodywork concern. nother new Verheul model is the Panorama VB59 coach, tble for its modern lines and generous glazing. Various body :s are offered, ranging from 48-seaters to 40-seaters with bar toilet. Thus bodies can be mounted on most types of ;sis or a coach can be supplied with integral construction. A :1 touch is that the windscreen and rear-window glasses are rchangeable, so that in the event of a broken windscreen a window could be installed as a makeshift.

,ustin 3-ton forward-control chassis form the basis of two ler new Verheul projects, a 23-passenger bus and a 640t. van being offered by the Austin agents, R. S. Stokvis Zonen N.V., Rotterdam, as standard models.

n air-suspension system is shown on the Verheul stand, having been developed. by Netam as a conversion unit for -spring chassis. The front spring-hanger brackets are tned to form the pivot points for fabricated trailing arms, qt consist of short leaf • springs clamped to cranked arms. the rear ends of these arms are Continental double-conlion bellows, above which are located the surge tanks. conversion looks a particularly simple method of applying suspension to existing vehicles.

!though the merger between Verheul and Kromhout ially means that the name Kromhout will disappear from cies, a normal-control Kromhout tractor is exhibited on Verheul stand. The disappearance of this name is corn;ated, however, by the appearance of a new one—AS. .is on a six-wheeled forward-control chassis built by nidt's Autoand Motorhandel, Amsterdam, who are lmins agents. The new vehicle is made up from a used .sis in which has been installed a Cummins N.H.-180 b.h.p. oil engine.

onsiderable ingenuity is to be seen on the stands of the ;ft trailer and equipment manufacturers, although most of novelty is centred on air suspension. Several mannurers—Broshuis, Burg. Pacton and Zwalve—show tandem axle semi-trailer installations using General air pillows and the General system of axle by several British companies.

This type of installation, however, is not popular with some Dutch operators because of its comparative lack of roll resistance, an important consideration in the case of tanker trailers, and to overcome this defect Burg have modified the system by incorporating an electrically controlled series of compensation valves which ensure that any tendency for the trailer to tilt is immediately corrected by raising the air_ pressure on the lower side. This Burg trailer has no dampers, which suggests that the electrical compensation can give a damping effect also.

General air pillows are also used by Netam (in addition to D.A.F., whose systems have already been described), and the Netam installation is interesting in that it has self-steering axles. Although the resulting system is somewhat complicated compared with the normal General layouts, close inspection reveals that it is more simple than initial impressions imply. Netam have found it necessary to offer this steering axle arrangement because their normal steelspring trailer bogies also have steering axles, and the installation allows sideways movement of just over 3 in. at each axle.

To do this. Netam mount the General air pillows inside two deep channelsection pressings, and below the pillows at each side, there are light leaf springs which provide the necessary lateral location whilst still giving the self-steering effect. The roll problem is catered for by the provision of a pendulum valve, which is stated to give satisfactory roll compensation as shown by experience with trailers of this type which are already in service.

There are several trailers equipped with Continental bellowstype air springs, including a Netam four-wheeled model with independent suspension employing a system of trailing arms with the bellows behind the wheels. Another important Netam development is the use of German Saalmann hydrostatic drive equipment on a Henschel concrete agitator, the SaaImann pump being driven off the front of the engine crankshaft, whence the fluid is piped to a hydraulic motor situated under the agitator. drum. This layout dispenses with the need for an auxiliary engine and simplifies mounting to varying types of chassis.

Continental bellows are employed on a Zwalve four-wheeled trailer also, but in this case there are four bellows per axle, these acting on a floating cross-beam to which are pivoted the rear ends of 1-section trailing arms on which the axles are trunnion-mounted. This installation should give good anti-roll stability as it enables the pairs of bellows to be located directly behind the wheels. Lateral location is provided by Panhard rods.

General Tire and Rubber diaphragm springs appear on a Burg four-wheeled trailer, the only instance of the use of this type of air spring on a trailer. As with the Netam layout, the springs are mounted at the rear of trailing radius arms with the axles immediately ahead of them. A Pacton fourwheeled trailer is shown with Dunlop air springs, a trailing-arm layout being used.

Whilst it is obvious that concerns like Netam have devoted considerable time and energy to the development of airsuspension systems, Netam themselves have another string to their bow in the shape of the French Coder progressive rubber suspension which was introduced for the Paris Show last October. This is being made by Netam under licence.

Of the German exhibits, the two most interesting models are the Magirus-Deutz and M.A.N. passenger chassis, both of which have somewhat complicated " open-type" tubular chassis frames and air suspension. The M.A.N. bus, which was seen in prototype form in Frankfurt in 1957, uses Continental diaphragm-type springs, the independent front suspension layout being similar to that of the Guy Victory air-sprung disc-braked chassis, which is also on display. The rear suspension consists of radius arms, approximately 10 ft, long, with diaphragm units behind the axle, and to lower the frequency each rear spring has a large surge tank directly above it. This M.A.N. 760110C1 chassis, generally, looks extremely complicated, and servicing might prove awkward, but despite this nine have already been ordered by a Dutch operator and there are many in use in Germany,

Unusual Front Suspension

The Magirus-Deutz OS-5506H chassis, which has a Deutz V6 125 b.h.p. air-cooled oil engine mounted at the rear and is intended primarily for integral construction, also features independent front suspension, the system employed being more than a little unusual.

The front wheels are carried on the outer ends of transverse swinging arms which are crossed, so that the pivoting points of each arm lie on the opposite side of the chassis from their respective wheels. Outrigged from the frame at each side are brackets which carry Continental bellows-type air springs, and fore-and-aft location and braking-torque reaction are provided by forked radius arms. The use of the crossover layout ensures maximum possible length of swinging.arm to give a large radius of movement when the wheels are deflected.

At the rear there are four Continental bellows, one ahead of and one behind the axle at each side. The axle itself is carried on tubular longitudinal members, at the ends of which are the bellows, and torque reaction is provided by two light radius rods below the axle and a two-leaf longitudinal spring running across the top of the axle. This leaf spring additionally provides a measure of lateral location:. About 90 of these MagirusDeutz buses are in operation in Hamburg.

Another new German exhibit is the Hanomag Kurier forward

control 2-tormer. The chassis layout of the Kurier is reminiscent of the Thames and B.M.C. forward-control light vans, in that the engine and radiator arc set back in the chassis

c22 frame to lie behind the centre line of the front wheels. Being a bigger vehicle, however, good use of this is made by providing a third seat over the engine cover and a clear floor from door to door, the gearchange being on the steering column.

Another interesting light German vehicle is a special version of the Volkswagen carried out by Pon's Automobielhandel NN., Amersfoort. The conversion has resulted in a large-capacity van primarily for bread and biscuit delivery, and the wheelbase has been increased to 11 ft. 2 in., enabling a 320-eu.-ft. body to be mounted, as-opposed to the 170-cu.-ft. body fitted as standard.

On the Ford stand there is the first presentation of a new German Ford van based on the Taunus I7M estate car. This is a particularly attractive vehicle, rated for a payload of ton, and the powei. unit is a 1.698-litre 67 b.h.p. petrol engine which drives through a three-speed synchromesh gearbox. The van body follows typical American lines of having a steeply raked top-hinged door.

Swedish vehicles are particularly popular in Holland, and the two main Swedish manufacturers—Seania-Vabis and Volvo —have large stands.. The principal Scania-Vabis exhibits are the new L.75 models which, like their predecessors, are normalcontrol vehicles but have a new 10.26-litre six-cylindered directinjection oil engine which develops 165 b.h.p. at 2,200 r.p.m.

The L.75 range includes fourand six-wheeled prime movers and tractors and was briefly dealt with in The Commercial Motor dated January 2, 1959. The standard Scania-Vabis cab itself is little changed, but is extremely popular in Holland because of the degree of comfort it gives, particularly in cold weather.

Sr:ania-Vabis are fortunate in having extremely lively Dutch distributors—Adr. Beers, N.V., Rijswijk—and they have done several conversions of the L.75 chassis to forward-control, normally fitting de Graaf cabs. When formulating this conversion it was originally Beers' intention to try to fit a tilt cab, Mr. Beers himself having built a tilt cab well before the war, in advance of any of the American designs. This was ruled out because of the price and possible complications, but good access to the engine has been achieved by mounting the radiator on vertical hinges, so that by releasing a budget lock the whole radiator can be swung to one side without disconnecting any hoses.

New Differential Lock The Beers' stand features several of the running units from the Scania-Vabis range, including an air-operated differential lock which can be fitted in any of the Scania-Vabis singleor double-reduction axles. The 6 x 4 chassis exhibit, in fact. has this differential lock in both its axles and in the third differential so that under very had conditions the drive to all four wheels can be locked.

The standard of bodywork to be seen among the bus and coach exhibits is, if anything, of an even higher standard than is normally to be seen at the Dutch Show. Styling is generally restrained without being too plain and the interior finishes are particularly luxurious. Typical of this is the latest Konig Riviera coach, an example of which is seen on a Sean ia-Vabis front-engined chassis. This 41-seater has individually adjustable seats, and passengers in the seats next to the windows have the added luxury of little side-tables each carrying a reading lamp on a flexible stem. Plastics trimmed panels are used extensively by KLinig and most of the other bodybuilders. 'A Roset coach, also on a Scania-Vabis chassis, has a high general floor line with a drop section at the rear which houses a lavatory, refrigerator and additional luggage capacity. The four rear pairs of seats face each other and can be arranged to form two single beds. Each seat has a microphone with which passengers can make contact with the courier at the front of the coach. As with the Ktinig body, there arc individual reading lamps, and folding tables are fitted. .

Features common to many Dutch coaches are the use of paired headlamp layouts and deep rear windows. In many cases the rear roof panels are carried out for a few inches over these windows to form a slight peak, styling also to be seen on modern Italian private cars, whence the idea was probably taken.

Goods bodywork also is showing increased signs of the use of plastics, and one of the Pacton trailers is exhibited with Blipol colour-impregnated plastics sides and tailboard. Several of the refrigerated vans have plastics interior panels.