et's design a British coach to beat the Continentals
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Shake off the `charabanc
outing image,' says D.Lloyo
THE TYPICAL British touring coach is still basically what it has always been — a lorry with a passenger body on it.
But I believe that a new super coach, a British Premium Specification Coach, could be built, and at not too 'great a cost. It is certainly needed, both for the home market use and for export.
Depending on the amount of money available, I suggest three stages in the development of a new coach.
The first one is simply a modification of a current model, eliminating some obvious shortcomings.
For stage two we move into higher gear altogether. It only needs an operator with national pride to make this specification a reality to prefer using a British vehicle to a foreign one.
This stage two coach would be as good as the best Continentals — at half the price. But development costs could make ,building the prototype more of a patriotic venture than a financially viable one.
For the third stage, the Moulton coach (CM July 30) is so far ahead of the competition that it is difficult to understand why a manufacturer has not taken it up.
To develop the Moulton coach into an export winner would cost only a minute fraction of the hundreds of millions poured into bankrupt companies.
The second stage is to build a new coach, using components already in production, or nearly so.
This involves using a current heavy-duty chassis, but with improved cooling, brakes, suspension, power weight ratio, transmission, steering and tyres, and a body considerably modified to improve silencing, cooling, heating, demisting, luggage space, access, ground clearance, seats and driving controls.
Interior noise
" Some development costs, largely to solve the problem of excessive interior noise, are involved.
For stage three the prototype coach built by Moulton Developments Ltd appears to be the ideal basis for development.
Each stage can now be described, but first the present, rather complicated, position regarding official regulations covering coach design and construction must be considered.
The Department of Transport .says that the PSV (Conditions of Fitness, Equipment and Use) Regulations 1972, are still and will remain fully in effect.
ECE Regulation 36, describing uniform provisions concerning the construction of public service vehicles, is sponsored for the United Nations by the UK and France.
It is not effective in Britian, and countries who ratify ECE Regulation 36 will be able to "E" mark coaches which comply with this regulation, either for use in their own country or for export.
However, ECE Regulation 36 does not cover the full requirements for the UK, and therefore a number of conditions of Fitness Regulations will still need to be complied with before an operating licence can be issued.
For the immediate future the vehicle builders in this country will therefore have either to meet the Conditions of Fitness Regulation 1972 or meet ECE Regulation 36 plus various Conditions of Fitness requirements. The ECE Regulation 36 includes additional regulations covering loading conditions, number of passengers carried, strength and a multi-function emergency switch. It also requires a minimum of five exits, including emergency exit windows, on coaches with more than 35 seats, plus one escape hatch in the roof.
Stage one is the modification of a current model and, as the Duple or Plaxton bodied AEC Reliance or Leyland Leopard is the mainstay of many of the largest fleets, it is a logical choice for the basis.
The first stage coach consists only of bodywork modifications and simple mechanical modification to such parts as the cooling system. Although opinions about appearance are subjective, my experience suggests the Panorama Elite I body was considered the best looking in recent years.
The large windows of the Panorama Elite, particularly when on a 12-metre body, were much admired overseas, and the simplicity of line and front and rear treatments were bet than most.
However, the Supreme w its deeper windows, does seem so attractive. Sol details, like the locks and 1 deep dirt trap footwell rou the pedals (when on a Reliar chassis) are poor.
On the Dominant II body, t small rear window destrai from the appearance and Ithe disadvantage -imports when overseas -that it is r interchangeable with the wir screen.
Considering, therefore, Dominant! body, the suggest specification includes: Seats not more than 49 in a 12-mel or 41 in a 10-metre to all( adequate knee room for t longest legs, with enough roc to fit seats with a limited ran' of back adjustment -f example, Chapman or similar But it must be emphasis' that headrests should definitE not be fitted as they block tl view. The predominant uph( stery colour should be a restf one like green. Picnic tabf and large ash trays are useft they must be so designed t they are not a safety hazard he event of a crash. Rooflights: Passengers fer badly from the heat in hot ather, so extra rooflights uld be fitted, four between existing five in a 12-metre, 3 of which would be an ape hatch to comply with E Regulation 36.
VVith eight rooflights open at front, enough air should be ioped in when moving to ip the interior cool, and the rmost rooflight opens at the ;lc to act as an air exit.
Fine wire mesh in front of the ,flights keeps insects out, i these extra rooflights would p prevent the interior of the ich heating up like an oven en parked in hot sunshine. Doors: Most Continental iches have rear passenger ars, but they seem to be out favour in the UK. As well as icker access, a rear door riinates the chaos which iays results if passengers are ding or unloading hand 'gage.
One with fold down steps jid be fitted on the nearside the second window from the k.
The right-hand emergency Dr has to be within 10ft. of
rear of the coach to comply. :h Section 23(5)(d) of the CoF • gulations 1972, but there ,uld be a second right-hand or, also with fold-down steps, mediately behind the driver. Idio and public address:_ d usual system fitted to tish coaches is of poor ality, typical defects being or reception on the radio of ;tent stations (partly due to
pathetic little aerial); interence from electrical equipmt, particularly fluorescent hts; and feedback from the crophone through the loudDakers.
The radio should be in front the courier seat to comply th Section 37 of the CoF gulations 1972, which says it the tuning knob must be t of the reach of the driver_ The right-hand drive mirror ould be moved from the ngerous blind spot position, d the left-hand mirrors, one tin and one slightly convex, ould be mounted on a Bed-d lorry-type folding 0 bracket
that they can be seen 'ough the passenger door. The present fashion of Dunting left-hand mirrors for3rd is stupid, as forwardpunted mirrors are of little use bad weather because no ndscreen wiper cleans to the treme edge of the screen, and ay are more vulnerable to
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damage when manoeuvring in a tight space.
The output from the air blowers in the luggage racks should be increased, so that there is a better cooling when the coach is not moving or only moving slowly.
This could be done by putting in a blower box at each end of the racks, instead of one in the middle, so that the air flow is doubled.
To facilitate loading cases and cleaning out the luggage boot, a part of the luggage boot floor and centre section of the rear bumper should hinge down.
At present, because of the difficulty of cleaning the luggage boot without a vacuum cleaner, it usually is not done and passengers' cases get' scratched.
One final modification, not bodywork, would be to 'fit it' an extra large radiator, or possibly two standard radiators, under. the front of the coach.
These would be connected in series with the existing floor radiator and a thermostat controlled fan such as the Dynair which is an option for Leyland Leopards, used If the extra radiators provide enough cooling to keep the fan cut out, except in heat waves, there would be a useful reduction in noise.
The second stage coach
The first stage coach will have better engine and pas senger cooling, access and seats than most current models. It will also be quieter when the engine fan is not working.
But to improve chassis features — brakes, suspension, power weight ratio, transmis sion, steering and tyres — and bodywork features (heating, demisting, ground clearance and luggage space) as well as trying to reduce interior noise to an acceptable level, it is necessary to proceed to the second stage of a new coach.
This is one with the chassis based on an AEC Bristol or Leyland frame and the body based on the modified Duple Dominant of the first stage.
If integral construction is used, then a rear-engined coach is preferred because it is easier to reduce interior noise. But, with a separate chassis, the underfloor lockers are awkward to use, so a mid-engine is better.
The AEC has the advantage over the Leyland PSU5/4R or Bristol of fewer installation problems.
If a Leyland TL12 engine is used a Reliance 6U37R frame strengthened to transmit the torque from a 220kVV (295 bhp) engine, is the basis for the second stage coach, suitable for 12-metre bodies.
There is no 11-metre version as this size, although very popular, is an unfortunate compromise, having the running costs of a 12-metre with fewer seats.
Engine .
An engine in the 220kVV or 300bhp class is required if the premium specification coach is to compare in terms of power weight ratio with the top Continental luxury touring coach. This is the Mercedes Benz 0303 powered by the 0M403 vee ten engine rated at 240kW (320bhp) and resulting in the truly Teutonic power weight ratio of over 20bhp per ton or about 15kW per ton with a 12-metre, 53-seat body.
However, many German coach operators prefer the less expensive 0303 with PM402 vee eight engine rated at 190kW (256bhp). A road test and operational trial of both manual and automatic transmission versions of this model appeared in CM October 10, 1975.
British-built engines comparable with the OM 403 include the Dorman and General Motors turbo-charged vee eights, the Cummins NT 335, 350 and 400 and the Rolls-Royce Eagle 320 and 340, with the Leyland TL 12 as a less powerful alternative but comparable with the OM 402.
Of these, the vee eights have high specific fuel consumption, and the Cummins with 140mm (5.5in) bore have a high combustion noise level, so for the second stage coach, only the Rolls-Royce and Leyland engines are considered.
The advantage of the TL.12 is that it is based on the AV 760 engine and has the same cylinder block, so development of a horizontal version to fit the 6U37R frame should not be too expensive.
However, the Eagle engines have more power available when required for hill climbing or overtaking, and are quieter owing to the smaller bore and lower maximum engine speed.
The main advantage of the Eagle engine is the considerable sales appeal of "powered by Rolls-Royce.This power unit would be the first choice in 240 or 225kW (320 or 340bhp) form for the 12-metre, with the Eagle 265 for the 10-metre coach.
Transmission
The high-power weight ratio eliminates the need for a multi-speed gearbox or twospeed axle. An ideal transmission for the premium specification coach would consist of a five-speed, semi-automatic gearbox with a ratio spread of about 6 to 1 and torque capacity of 1180N m (870 lb ft) driving a single reduction back axle with a lockable differential, and a ratio which gives motorway cruising speeds at the most enconomical engine speed, I there is no SCG fluid clutch sufficient torque capacity.
Thus the gearbox sugges. for the 12-metre is the S5-150 which is a five-spei synchromesh. gearbox with ratio spread of 5.1 to 1 anc torque capacity of up 1470Nm (1085Ib ft). An portant advantage of t gearbox is that it can supplied with a Fichte! u Sachs WSK 400 torque c( verter and clutch as describ in CM January 2, 1976, input torques up to 1225rN (905 lb ft), giving consideral protection to the drive line, well as the smooth accelerati which is very important passenger comfort. For t 10-metre the gearbox would the four-speed S4-100, cc pled to the WSK 400.
Brakes
Good brakes, for use emergencies only, are the mc important safety feature, alo with suspension, steering a tyres.
The dual full-air system the AEC Reliance is satisfactoi as long as the severe chas vibration, which accompani anything more than light use the footbrake, can be elimin. ed Strengthening the 61„13: frame for the Leyland TL 12 Rolls-Royce engines should al achieve this. A good retarder also important The other requirement I the second stage coach brakii system is a Dunlop Maxar anti-skid device on both axle The Maxaret is well known anti-jack-knife device for ;iculated lorries, and Dunlop ys that is is not yet available fitting to an existing coach. it it could be incorporated at a initial design stage of a new adel.
It must be wired so that it Dcl u I ales the Telma when in e.
uspension
If the coach can always run Ily loaded on reasonably good ads, conventional semi-ellip; springs with shock absorbers e satisfactory. However, if the lach is running only partly Ided, there can be consideraa pitching on all but the loothest surfaces. In this case ' suspension is required.
eering
Power steering is essential, cause with manual steering a ver would have no chance of aining control in the event of ront tyre blow-out at speed.
res
ith a 53-seater, fully loaded, ing a long motorway run in a atwave, the tyres get so hot t it is doubltful if the 10.00 x (11.00 x 22.5 metric) size d on AEC and Leyland ches is sufficient.
It would be a good idea, refore, to use oversize tyres, ely 12 00 x 22.5. Advanes include a better ride and ater safety margin, but more ortant the lower pressure larger area of contact give roved braking.
dywork and silencing
Basically, a Duple Dominant I body with modifications listed under the first stage, plus an additional major modification to improve silencing.
This consists of raising the body by the amount by which the wheel arches intrude and filling the space with sounddeadening material (acoustic .cladding) over the major noise producing machinery such as engine, fans, transmission including rear axle, exhaust and air intakes.
There would be acoustic cladding on the side panels so that engine noise reflected off the road surface would not be transmitted to the inside of the coach. The present space above the engine would be retained for cooling air.
The amount by which the body is raised will be more than the usual wheel arch intrusion because of the 12.00 x 22.5 tyres, but it could be even more if it is found that a layer of accoustic cladding inside the wheel arches reduces tyre noise.
Any means of reducing tyre noise should be investigated because, when both engine and wind noise are reduced, tyre noise becomes the main component of overall noise.
Exhaust noise could be reduced by increasing the size of the silencer and leading the exhaust pipe to the back of the coach, instead of finishing it at the rear wheels.
The Dominant has a steel sub-frame to comply with ECE Regulation 36, but this requirement seems to be a crime example of bureaucratic legislation.
A crash which involves the coach turning over is a major accident, fortunately very rare in the UK, and it makes more sense to concentrate on safety features intended to help avoid accidents — hence the emphasis on brakes, steering, tyres, suspension and controls.
In any case, a sub-frame strong enough to support the weight of the chassis in a crash would be so heavy that the coach would be top heavy. Very dangerous!
Heaters and demisters are not very important in a coach used only in summer, but forone used all winter — as the premium specification coach would need to be used to recover its high cost — something better than heater boxes is required.
A better idea would be a continuous box running the whole length of the side of the coach at floor level and against the side, with the air outlets pointing towards the centre of the coach. The heat exchanger would be a long narrow radiator inside the box and the motors to provide the air flow would be under the floor.
If the coach has to be parked for any length of time in cold weather and kept warm — if waiting for a theatre of night club party for example — a hot water heating system is no good.
Choices include Webasto derv-fired heaters already used by some operators, but there must be a heater on each side of the body, not just one side, and this uses a lot of side locker space.
Another choice is electric heating, the current coming from the 10kW generator used to drive the fan. This would be driven, when the coach was parked, by a donkey engine in one of the side lockers._ Demisting of side windows with cold air does not work, but it might if the air was hot, so a heating element is included in the luggage rack air boxes.
Since side-window demisting would be required only when the vehicle was moving, or about to move, this heater could be electric.
Alternatively, double glazing could be used, but the thickness of the units must be kept down because it will come off the interior width. With double glazing, the second stage coach qualifies for the maximum four stars under the German Bus Komfort Star rating (CM December 27. 1974).
Windows
Darkened or reflecting glass side-windows should not be used. They stop passengers taking photographs from the coach.
The specification of the second stage coach is intended to eliminate as many possible disadvantages of present-day British coaches while retaining the advantages.
But, to keep development costs down, it is based on the traditional concept of a coachbuilt body on what is virtually a lorry chassis and thus some of the disadvantages inherent in this system of manufacture will remain.
it is, in effect, still applying "lorry thinking" to a passenger vehicle.
The body is basically a Duple Dominant I, but the use of this body means that wind noise at motorway speeds will remain high.
Third stage
It would be possible for the third stage to develop a new low drag body for the second stage chassis, but this would be another intermediate design, and, as the third stage is intended to be the final version of the coach, it is better to make this a completely new design. concept — not bound by traditional principles — as was done with the Leyland National bus.
Various projects, such as the Duple "pusher bus", have been described in the trade press_ and the one which appears, on paper, to be a potential winner and which already exists in prototype form, is the Moulton coach.
The low unladen weight of 7.4 tonnes (7 tons 6cwt), low axle weight and drag factor of 0.4, together with the 90 per cent retardation and Hydragas suspension sound particularly advantageous, while the use of components from current British Leyland commercial vehicles should keep production costs low.
The Hydragas suspension, together with an eight-wheel configuration using 9.50 x 17.5 wheels, is said to give a better ride than a Rolls-Royce Silver Shadow.
The power weight ratio is low, but this could be increased. The appearance• needs improving but this, too, should also be possible. Appearance, says the description of the prototype, can be modified to suit prevailing fashions.
Thus a production version of the Moulton coach should provide passengers with a much improved level of comfort — so important on long-distance tours — and meet the requirements for a premium specification coach for the foreseeable future.
The much modified conventional coach (second stage) would be for use until sufficient numbers of the Moulton coach were available, and until sufficient service experience' had been obtained with them. The second stage coach could be in production by 1976.
The first stage is a short-term stop-gap which could be introduced in 1977, and subsequently would be produced for use on tours which did not justify the much more expensive second stage coach.
However, some informed guesses can be made on the basis of the cost of extra components added to the standard specification.
The cost of uprating a Reliance chassis, to include a 340bhp engine, appropriate cooling system and frame torque converter, 55-150 gearbox, Maxaret and air suspension is about £4,500. If the same amount is allowed for the extra cost of the raised and modified body compared with the basic Duple Dominant I, ,then the 12-metre second stage coach will cost £9,000, plus development costs, more than the standard Reliance/ Dominant. For the 10-metre with 198kW (265bhp) engine, this figure could be £.8,000.
The amount to be added for development depends on the anticipated volume of production. This can be estimated only by speculation • about the number of very expensive coaches used by British operators, which could be between 30 and 40 for touring applications, with possibly between 10 and 20 prestige vehicles — say 50 altogether.
Leyland points out that any estimate of development costs made without a cost study programme would be, at the very best, a wild guess. Taking a round figure of £100,000 as an example, the cost per coach is £2,000, so the 12-metre second stage coach would cost £11,000 more than the standard model.
To put this figure in perspective, it must be related to the amount it adds to the cost of a seven-day tour and, assuming an 80 per cent load factor, that is 40 passengers per week for 20 weeks per year for five years. Every £1,000 added to the cost of the touring coach adds 25p to the tour price. so £11,000 adds £2.75p, but VAT and interest charges increase this to about £3.40.
Operating costs of the premium specification coach should be about the same as a cheaper model if the higher insurance premium is balanced by improved reliability.
For similar routes and running times fuel consumption would be slightly less, as turbocharged engines are more efficient than naturally aspirated. £3.40 is about 5 per cent of the tour price as, at 1 976 prices, very few seven-day tours cost more then £70.
A quality tour would cost more than this, because it would stay in more expensive hotels and provide better meals. The price would probably be in the £80 to £90 range and the proportion due to the use of a premium specification coach would be less than 5 per cent.
These prices refer to British tours, but Continental tours are more expensive, the extra cost of the coach becoming insignificant. Also, the luxury coach is more important on Continental tours because more travelling is included.
The 80 per cent load factor could be achieved if the tours were advertised with the emphasis on quality rather than price. The third stage Moulton coach could well cost less than the second stage coach, because of the extensive use of components from commercial vehicles already in production.
The price of the British premium specification Coach should also be compared with that of leading Continental models, in particular the Mercedes Benz 0303.
There are numerous versions and several sizes of 0303, but the most popular in Germany is the 12-metre, 53-seater, with the OM 402 engine. This costs about 200,000Dm (£50,500) with no extras, but to the usual minimum touring specification it is about 230,000Dm (£58,100).
This would include a refrigerated drinks compartment, the comprehensive Blaupunkt "entertainment centre' and manual transmission by a ZF six-speed gearbox.
Extras like air conditioning, and the most expensive seats with special covers and adjustment for width as well as back angle, increase this to about 260,000Dm (£65,650), while the most expensive versions with the OM 403 engine and all the extras cost over 300,000Dm (£75,750). The sinking pound increased this from £50,000 when the 0303 was first announced (CM October 11, 1974) to over £75,000 two years later. A cheaper version of the 0303 is a 10-metre, 43-seater, with automatic transmission and the OM 402 engine, for 180,000Dm (£45,500).
The layout of mechanical components in the rear engine compartment and having only four grease nipples, makes servicing easy, but the main operating economy is the anticipated long engine life. Based on 0302 experience 350,000 to 400,000km is expected per engine, while up to 600,000 to 700,000km is possible.
The British premium specification coach at £38,000 costs a lot less than the 0303 at 1977 prices, and the long-term running costs of the British coach are even more favourable.
Rolls-Royce anticipates a life of 600,000 miles from an Eagle engine with a top and overhaul at between 300,000 and 400,000 on heavy truck use, which is more arduous than coach use.
Since few touring coaches run more tham 30,000 miles a year, a 20-year-life is possible, provided the interior is thoroughly cleaned every year and furbished occasionally. Alternatively, the coach could be sold for a good price after 10 years.
The second stage chassis with TL 12 engine, less sopl ticated transmission such as Fuller T0-905B with 3.70 r axle or TO 905F with 4.11 r axle, cart springs, and 12-m( 75-seat high floor body like Duple Goldliner or Plaxt Viewmaster, would make ideal vehicle for UK expr service work.
The improved reliability high mileages would give lo\ long-term costs, so it is un. tunate that the operators large fleets of express vehic cannot afford the initial cost, increased volume of product of the chassis would reduce price of the premium specifi tion coach.
The main aspect which r tricts high capital investment modern vehicles is low prc ability arising out of charg prices which have not kept with inflation.
To take just one examr excursions from South Yo shire to the East Coast resc and other popular destinatio were provided by United Mc Service. in 1939 at mos between 10s and 12s 6d.1 same excursions now run National Travel (North East) c between £1.50 and £2.E while private operators char even less!
Coach operators need shake off the ''charabanc o ingimage and charge realis prices to attract passeng( prepared to pay more to travel a better vehicle.
Another reason is the ext mely conservative outlook of t British commercial vehic industry. A proposal to mar facture a premium specificati coach would be answered wit -Why bother to introduce a ra model for a small home markt It is too expensive, and a operator who wants such vehicle can buy a foreign one.
They might go on to say th they can still sell their existii models, conveniently forgettii that they have lost export mr kets because they sell outdate vehicles.
It should be possible to ma a prototype second stage coac Leyland has said it could put price and delivery date on Reliance chassis fitted out described after undertaking detailed study of the propo tion, while Duple would quc for a suitable body, although n for delivery before 1978, owii to full order books.
Duple also wants it mai clear that this article in no vv gives details of any suggest( development plans for ti Gold liner.