Straight talking on the Roadtrain
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EYLAND'S new vehicle Roadain — or T45 — has been a mg time coming. At various ages of its development LV's tanagement told us "We will at be hurried: we are going to at this one right — down to the st piece of paper — before we unch it."
During the development CM as been with the vehicle at ayland and in Canada we've riven it on a short appraisal an. No one outside Leyland has aen able to subject it to a road ist as severe as our longstance route.
We knew enough about T45, ad its developments, to put the uestions fleet engineers and aerators would ask given the lance.
Last week we met represenitives of Leyland's managetent in London at a round table ,scussion.
Our guests were Chris hristianson (marketing tanager, Leyland Vehicles), revor Longcroft (product affairs tanager), and Jim Mason (chief igineer, vehicle engineering, ayland Vehicles). The round ible was chaired by CM's 3sistant editor John Durant, ad CM experts Graham Montomerie (engineering editor) ad Tim Blakemore (technical Titer) asked some searching uestions.
im Blakemore: lany operators will ask, at the utset, what is the exact price of 45 Roadtrain?
hris Christianson: he list price is £24,995 B: How long do you expect to .old that price?
Until our next price inrease, which will be within hree months, but certainly hrough the public launch ,hase.
'B: The 1628 is the first of the 45 range; how many do you nticipate selling in the first ear?
:C: We plan to sell 1000 in le first 12 months and we have lready sold 250 before the lublic launch.
iraharn Montgomerie: ; it possible for you to predict ow long you anticipate connuing demand for Marathon fter the T45 launch?
:C: Marathon will continue in redominantly proprietary enire (Rolls and Cummins) form ar approximately 12 months. 1M: When, if at all, are you oing to fit proprietary engines the Roadtrain range?
X: The engineering pro
gramme has included work on fitting of proprietary engines and they will be made available within the first 12 months of the public availability of T45. Trevor Longcroft: Marathons will continue with proprietary engines for 12 months. Then, as proprietary engined T45s come on stream, we will phase out proprietary engined Marathons.
GM: When we talk about proprietary engines we can anticipate the makes, but which ratings will you be offering?
TI: I don't think we want to go into that at the moment.
CC: We will reflect the basic market share of the proprietary engine suppliers in the fitment pattern of the proprietary engined T45.
JM: The T45 vehicle packaging is such that we have tried to make it as flexible as possible to accept different engine installations. The frame is profiled down and is broadened at the front. There is a large amount of room in both the engine bay and under the cab.
GM: That's fine from an engineering view, but from a marketing point of view, are you going to offer the higher-rated Roils and Cummins engines which you didn't do when you went proprietary for Marathon? CC: The market then was really more into 260bhp. The engineering programme incorporates the higher-rated proprietary engines, but I wouldn't want to offer proprietary engines unless we had to. We may have a different market strategy for the fitment of proprietary engines in Roadtrain than we have in Marathon. It may be made more difficult to have a proprietary engine in Roadtrain, so we may have some form of price disincentive.
TB: What exactly are the differences between TL1 2 engines in Roadtrain compared to Marathons? JM: Very broadly they fall into three areas. They are changes relating to performance. This is a reduction in engine-governed rpm, better torque back-up, or Flexitorque, this is related to fuel-injection equipment and turbocharging. In the second category we have improved the durability and reliability of the unit and there are quite a number of small changes there. Then there is a third category of change to suit the installation of the engine in T45. For instance, we wanted to mount the fan midway between the crankshaft and the waterpump so we had to produce a special fan drive.
GM: You have got seven per cent more bearing area on the crankshaft; how have you achieved this, is it diameter or length?
JM: That claim is something that we wouldn't, from an engineering point of view, really push. I wouldn't pretend that that's a change that we can sell the TL12 engine on.
GM: T45 has a non-aggressive appearance. Is an operator influenced by "non-aggressive" cab styling?
CC: Not very much. I think he judges a vehicle on its performance and the whole-life operating costs. The impression T45 gives is very modern. The fact that it is also non-aggressive is a secondary issue. I think it has dated a lot of other cab designs.
TB: One of the claims made for the cab is that its drag coefficient is 30 per cent less than an equivalent cab. What is the actual figure for the T45 drag coefficient?
JM: We have to be very careful when quoting drag coefficients that we compare like with like. On comparison tests, you can compare the C40 cab, with, say, the Ergomatic cab on Marathon. The difference in C40 is 0.64, and Marathon round about 0.89.
TB: Is this with the tractive unit on its own?
JM: Yes. Just the cab.
GM: You say the cab reduces wind drag by up to 30 per cent but you don't say compared with what. Do you mean 30 per cent better than a Marathon or 30 per cent better than an Fl 2?
JM: Were comparing with Marathon because we have those results. We haven't built a quarter-scale model of an Fl 2 or a MAN or any other make.
GM: How relevant do you feel the drag coefficient of the unit on its own is compared with its use in normal operation? I ask this because Volvo has come up with interesting figures in relation to the F88 and F10 cabs. As a solo vehicle, the F88 drag is superior to the F10, but when its coupled up to a tilt trailer then the F10 is better. Does that apply to the Leyland?
JM: Yes, It's bound to. What you couple to makes a considerable difference to what the Dye ra I I drag of the vehicle is. A aox-type refrigeration trailer Nith a fridge unit on the front las a big influence. The in4uence of box trailer height is .:onsiderable.
GM: You've angled the rear of :he cab forward — has this made any measurable difference to its 3 erodynamics?
JM: The cab was angled essen:ially for the compatibility of unit :o trailer. We didn't gain any ;ignificant aerodynamic advan:ages nor did we lose anything. :C: A lot of the wind tunnel Nork was done with built-in air ieflectors which Jim may want :o comment on.
/RC That was part of the deveopment programme. We're always looking at ways of mproving the aerodynamics of )udits. We've done a lot of wind unnel work ourselves and Ne've reached some interesting conclusions, but I'm not going to talk about them now!
TB: Did your market research show that angling the cab was significant for a number of operators who had vertical articulation problems?
JM: No. The consideration was cab space, and the clever bit about T45, compared with everybody else's vehicle, it that we've created more room in the cab. It's long enough to stow an occasional folding bunk and at the same time pick up 30 and 40in overhang trailers and couple within 15m. Not many vehicles can do that.
GM: In the gearing specifications, the highest available axle ratio only gives 64mph top speed. That's still over the legal limit, but in terms of effective engine speed for economy at motorway road speeds isn't it on the low side? I would gear for, say, 68 and road-speed-govern back down to 62.
JM: We set the top speed of the vehicle at that point and developed our driveline from there. It was a strategy that we felt reasonable to adopt in line with our aim of conserving fuel. We didn't believe that we should be gearing the vehicle for a 75mph top speed.
TB: You say you ruled out automatic and semi-automatic gearboxes on the grounds that long-haul vehicles spend 90 per cent of their time in top gear. Wouldn't that be a good reason for having a single-reduction rear axle and a direct top gearbox to improve efficiency? JM: No. You have to be careful when you assume that a singlereduction axle is going to give you benefits. This is not proven. What you must be concerned with is providing overall gearing to best suit the characteristics of the power unit. We can do that with the Spicer gearbox and the Leyland axle so then all you've to be concerned about, if you can gear the driveline correctly, is the hub reduction axle. Is it less efficient than the single reduction axle and are you losing more through it? We can't differentiate between single and hub reduction axles on efficiency.
TB: Not even if it's combined with overdrive gears rather than a direct top gearbox?
JM: You get back to gearing again. The overall gearing has to match the power unit. Maybe you can gear a vehicle without an overdrive, with a direct top if you have a suitable rear-axle ratio and a suitable torque characteristic from the engine. So it doesn't follow that you can pick .up any power unit, stick an overdrive box on it and a singlereduction axle and get the best benefits of fuel economy. What we are concerned with is a total matching of the complete driveline and that's where we've put our efforts. We've done a lot of work on that, and have now developed a very successful computer program. We don't any longer have to indulge in trial and error. The computer program is correlated with some of the field tests we're doing. We can input to that and very quickly find out the ideal, driveline situation.
TB: You've done that with the single-reduction axle and came up with the answer that there is no significant difference?
JM: In the early programme of T45, we had a single-reduction axle as part of the programme and then we were able to replace it in favour of our own hub reduction axles.
GM: When you tested the axle: for relative efficiency, did yoi :test them on their own or as par of the total driveline? Is th( 'difference that you can' measurepurely on the basis o axle against axle or is the non measurable difference takinc. the whole drive into account? JM: We've looked at it loctl. ways and we really couldn't fin( much difference.
TB: Other manufacturers seen to have found the opposite There has been a trend to offe single-reduction axles on th( basis that they are mon efficient.
JM: Our view is that th( efficiency differences that w( measured are within ex perimental error and that view i! supported by other manufac turers of hub-reduction axle who are concerned about claim: that single-reduction axles givE a much better performance. 1/114 haven't found anything tha leads us to believe that we nee( to design single-reduction axles GM: Operators say the onh reason you offer the hub reduction axle is because it's ar in-house product.
JM: I think that's probably true but it's a very good in-housE product.
GM: Still on the subject o. drivelines, did you go for thE Spicer because it was a spline: or because you wanted tha• particular gearbox?
JM: We started off the pro gramme with an open mind or transmissions, and since WE don't manufacture a suitabk transmission ourselves WE looked at Fuller, Spicer and ZF The Spicer choice resulted from our driveability concept. T4E was designed very much arounc the driver, and it was our vien that the splitter gearbox pro. vided driveability advantagnE
/er the range-change box. We 'en began to look for a suitable >litter box which was durable id reliable. We fitted someling like 25 Marathons with picer boxes operating in the eld with selected companies id they performed exceptio311y well. All of them have done rer 100,000 miles with no real roblems, so we were very appy that they were suf.3iently reliable and durable for le product. It's much easier for le driver to know where he is ith a splitter gearbox and just be able to flip a switch for the nailer motorway gradients.
B: What is the major selling oint for T45?
C: One of the most conspi„IOUS advantages of the vehicle its weight — its very light. It is le lightest 40-tonne tractive nit available on the UK market ld for those operators who are ayload conscious, then that is a reat incentive. However, a ehicle has to appeal to the river as well. Some unionised rivers have a very significant
in what is bought. There)re, the internal treatment, low oise level, and other human factors are important. So with low weight, good basic vehicle performance, specification, and the driver package that we have, T45 is a very attractive combination.
GM: One point I would like you to clarify on the T45 specification relates to kerb weight. You quote this with fuel, oil, and water on board. How much fuel is included?
JM: It's a full tank.
TB: Maintenance times are claimed to be sigificantly reduced on T45. Could you give us some examples?
CC: There were very stringent service times set for T45 across all major and minor service requirements. That includes engine out, clutch change, and brake reline. We met a lot of the targets, but at the end of the day it's sensible to come up with a package which in certain areas is a compromise. So, while a competitor's clutch, for example, may be easier to remove, we win on other exchange times.
JM: The programme was set up so that, on the very early prototypes, we did what we call SAM exercise which is a -service and maintenanceexercise. Our service department and fitters took units out, and we decided whether the resultant serviceability was acceptable. One example is the engine bay and the way the frame is profiled, and the amount of room there is to get at components. The engine bay without a crossmember interfering with the underside of the engine was another significant move but it gave us a technical problem. We solved it in terms of frame structural integrity because we were interested in achieving low service and maintenance costs. Here we refused to compromise.
TL: The time for a clutch replacement is 5.95 hours. For a brake reline including removal of wheels, shoes, relining the shoes and replacing everything, the time is 7.95 hours for the front axle and 8.5 for the rear. GM: How much of Marathon is in 145 totally unchanged — or has it all been modified in some way?
JM: The experiences of Marathon construction are embodied in T45. Take the engine — TL1 2 — obviously that has a lot in common with the T45, and the rear axle too. The changes are in the cab, frame, suspension, steering, even the wheels — they arb spigot mounted.
GM: Do you obtain greater spring control with shackles rather than slipper ended springs?
JM: We are very interested in ride on this vehicle. It was one of our major objectives. Our major concern was to keep the driver happy and one of the ways you can do that is by stopping his inside shaking about all over the place and his head wobbling. We put a lot of effort and money into ride. One of the things we found giving us inconsistencies in the ride pattern was slipper hangers because of the frictional differences you get in the slipper arrangement. You can start off with a slipper arrangement knowing the surface finish of the spring, and the hanger. You can grease that or put in nylon and produce a spring control rate that matches the vehnle. Our tests showed that the matching deteriorated with wear. In the end, for consistency, we went back to the shackle arrangement. If you service and lubricate the shackle, the dynamic characteristics of the spring remain as designed.
TB: Will it be your policy to choose the components, or will you go the American way where the operator specifies precisely what he wants?
CC: it's interesting that, in most countries in the world, the market leader has his own engine and his own gearbox. If you lbok at the world markets there ate relatively few proprietary packaged trucks which are market leaders. We are an engine manufacturer, an axle manufacturer and a vehicle manufacturer so we have a vested interest in selling our own components which package into a very good lorry. However, there is a demand from some operators for
Cummins or Rolls engines, for instance, and we're able to satisfy that demand. In some cases this is not via our main product range, but through our Special Vehicle Sales operation, and that's the way we will probably satisfy the demand from operators for ''specials''. s a simple convenient device which gives the operator what he wants at no cost to others.
TB: But if somebody comes in now and says they want to take T45 with, say, a Rolls engine in six months time will you accommodate them?
JM: We would be able to accommodate them. We have a plan which says that a proportion of our production will be for proprietary engines.
GM: Why did you go for wedge brakes?
JM: When we looked at the vehicle which we were designing for the 1980s, we were concerned to keep up with the trend towards legislation which looked as if it was aiming towards either some sort of mechanism for measuring brake wear or some monitoring device on brakes, the option to a monitoring device being an automatic adjuster. So, that was one aspect, that we had to bear in mind.
We then looked for a highperformance brake and, of course, Twinstop gives twin leading shoes. We were also looking at how we could reduce maintenance on brakes. The operator shouldn't have to tinker with and adjust his brakes every six weeks or whatever, he should be able to run with them between MoT testing, on an annual basis.
TB: Do operators feel the same way? Don't they feel that they would prefer to adjust the brakes every couple of weeks?
JM: The input we have is that they prefer not to do anything with the truck really except to have it in once a year, steam clean it, go through it, check it, reline if necessary, get the Department of Transport Certificate, and operate it for another year. That's the situation we are working to. We don't go along with the philosophy that says that you can park a 40-ton rig on one axle and so that was a definite requirement for us, we needed to park on front and rear axles. On a cam brake you have got a very large actuator on the front The twin wedge brake gives us the advantage of having smaller actuators. These smaller actuators and smaller movements mean a reduction in the required air capacity or, if the present capacity is maintained, there is more back-up from it. Operators told us they were looking for more progressive braking, high-rate braking, and so we made the decision to go with them. To sum up, the wedge, when compared with the cart: brake, comes out on top. TB: Do you appreciate that you have probably got quite a bit of operator resistance to overcome because of past experience with both automatic adjusters and Nedge brakes?
JM: Yes, we know there'll be some resistance to wedge Drakes. But we argued that if we Nere going to put wedge brakes pn T45 they had to be right. The ast thing we can afford to do is 3ut a vehicle in the field with Drakes which could be conJemned. To be sure we didn't fail here we set up an intensive Jser trial programme with both Rockwell and Girling on twin Nedge brakes. We converted aver 20 Marathons to both the Spicer box and the twin wedge Drakes. We also put twin wedge Drakes in other fleets using the 3uffalo and Bison. Whereas the Spicer gearbox was very suc-. ;essful, unfortunately in the intial stages we didn't enjoy the ;ame success with the twin i'edge brakes.
3M: At the Roadtrain concept itage no twin wedge system as suitable; now you are using me. Could you enlarge upon his?
JM: What that statement refers o is that when we tried the vailable twin wedge systems, :hey didn't meet our standards. GM; So you were going by your 3wn tests and not operator ex3erience?
JM: Yes, most suppliers are the same, every day of the week you get somebody walk through the Joor with the most tested, proven and reliable component in the workf. All you have to do is put Leyland on the front of it, snd we seem to get difficulties hat others don't.
rB How would an operator (now if the automatic adjustnent wasn't working?
IL: Although we say they don't nave to adjust brakes, I don't :hink we'd ever endorse a policy Nhereby the operator doesn't lave regular inspections of his vehicles.
GM: But that doesn't fit in with
The Leyland Christianson. Jim's policy of going from one MoT test to the next without doing anything to it.
CC: Within that period of course there is routine servicing at 6000-mile intervals. At the service you certainly can top up and adjust elements of the vehicle so you would never go more than say six weeks or so without having touched it.
JM: The mechanism is such that it is difficult to see how it really could not self-adjust without there being a significant problem with the brakes, which would mean the driver would notice it in performance.
TL: Would that argument apply to any other sort of selfadjusting brake?
JM: Yes, absolutely. .
GM: The secondary system has got full braking on the front and partial braking on the rear. How is that achieved?
JM: Halfway down the chassis you'll notice a plate of relay valves for the apportioned system. It's not magic, it's a case of just making sure that for a particular application you get a certain amount of air pressure to the appropriate activators, and you can do that by balancing valving within the valve supply body.
GM: Isn't it going to cause problems having a battery of valves? Don't they need adjusting or checking at regular intervals?
JM: This comes back to our service and maintenance concept. We felt that it was better to have a valve pack where you would go straight to it rather than have the valves scattered about the chassis. There are no more valves than there would be on any competitive vehicle, it's just we've grouped ours together. It gives the advantage that we can package the valve set of equipment and our biake designers have been through that. We've set up a rig at the plant and can build the package up, clamp it on the test rig, and run all the tests through it. This makes sure that all those valves are operating correctly and get ting input/output. We can . effectively monitor the most problematic side of the brake system. We run tests at the end of the line to make sure the connections are good.
GM: Are there any extra maintenance requirements for this batch of valves? Is there something the operator needs to set himself?
JM: Not at all. It's a characteristic of the valve and he wouldn't need to do any more maintenance than would normally be the case with the present air valves supplied by any of the suppliers you could mention.
GM: This system either works or it doesn't work. How does the operator know if he's still on the same proportioning system? Could it not happen that he's going to end up with partial braking on both axles or full braking on both axles?
JM: The vehicle does have a load sensing valve for its normal braking applications, and that's well-organised technology. We believe the test work we've done allows us to select the best load sensing valve that there is in terms of reliability, durability and consistency. What you are asking is about a failure on the secondary braking. There is no reason to think that this valve will be any more unreliable than any other brake valve: it uses conventional valving techniques. So your question really turns into "how confident are your manufacturers that the air valves you put on your vehicles actually will continue to perfori in the way they are set up to' We are very confident.
TB: With the next models c 145 range that will be intr.( duced, can we expect any majc changes from the 1628?
CC: We've already had a majc change of direction before T4 Roadtrain, which was Landtrai of course. This was launched fc third-world markets throug overseas distributors las November. The C40 can an will extend progressively OVE the next two and a half year Graham asked "Coul somebody put a T45 cab on Marathon?" It's impossible t put a cab on a chassis withot, major development work on th steering and suspension at th front end, but it will take plac as we replace the other vehicle in the range over the next tw years. What we've done at th moment is to replace th Marathon cab. The nex building brief is to replace th Ergomatic cab and then replac the replacement.
TB: It has been suggested ther is something more radical in th 145 range. What I'm getting E is the 1628 typical of the rest c the T45 range?
JM: I would say yes for the nex four to five years.
TB: You are saying the 14! concept goes beyond th immediate future?
JM: Yes, what you are snmp! now is the C40 cab. We hay. advanced vehicle concept which we will launch when th, market's ready to receive them TB: This presumably is after th, 145. So a natural cycle time, sheet-metal replacement MI reduce rather than increase thi time scale?
JM: Yes, but we haven't sai4 that the cab module or cab .sys tern we've designed is con strained to the sort of -configure tion and plan of the type you se, now.
TB: How many advanced on gineering ideas did you have fo 145?
JM: It isn't possible to list them GM: Do you expect any resist ance from the operators ,t( printed circuits?
JM: The electrics of the T45 ar( based on our wish to improv( the reliability of electrics ir general. I don't care whether it': a Leyland, Mercedes or MAN We all do reliability studies or competitive vehicles. To reducE that slice of it to nought is noi possible within one stage. What Leyland is aiming at with T4E it to increase our slice of the cake