Leyland Royal Tiger Questions

[boronia]

Thanks RK215

That is certainly an interesting concept. Thanks for the details, I can have some fun now trying to fathom out exactly how it would have worked.

Perhaps Leyland didn't have much faith in its linkage system??

[Herbert]

A former MTT Fremantle Depot driver mentioned to me recently that Royal Tigers originally had air-assisted gears, but I simply assumed he was referring to Worldmasters. Turns out he was in fact referring to "proper" Royal Tigers. Obviously something went wrong at some stage and the air-assisted mechanism must have been removed.

[Herbert]

Stumbled across this photo today: a Leyland chassis on display at the 1951 Perth Royal Show. My guess is it is Perth's first Royal Tiger:

<img src="http://perthbus.info/METRO-ROYALTIGER-1951A.JPG">

Sorry, the original is not high enough res to be enlarged.

[Dennis96]

IIRC was synchro gearbox, which to my teenage logic of the time seemed a backward step, coming after the Guy Victories with their two pedal CAV "mono" control.

[mrobsessed]

Far more fun when they ran out of synchro!

[RK215]

Stumbled across this photo today: a Leyland chassis on display at the 1951 Perth Royal Show. My guess is it is Perth's first Royal Tiger:

It certainly looks like a Royal Tiger, with those chassis outriggers. It's hard to tell for sure, but it also looks like an early model with left-hand handbrake lever. At least, there is not a lever visible to the driver's right.

Cheers,

[RK215]

Far more fun when they ran out of synchro!

The original Leyland 4-speed synchromesh gearbox was reputedly a bit troublesome in its early days, although perhaps more so in the vertical-engined models.

The second iteration (with synchromesh on 3rd and 4th only, but with constant mesh rather than sliding mesh on 1st) appeared around 1955, after Royal Tiger production had ceased. However, it would have been used on the Leopard, Royal Tiger Cub, and eventually on the Tiger Cub. Presumably this was an improved version.

Cheers,

[RK215]

Thanks RK215

That is certainly an interesting concept. Thanks for the details, I can have some fun now trying to fathom out exactly how it would have worked.

Unfortunately, the Leyland brochure is of little help in this regard. However, my best estimate is that a longitudinal air cylinder with bidirectional piston was used, which provided assistance to the fore and aft movement of the selector rod. Control would have been by a bidirectional “lost motion” valve connected in the linkage ahead of the air cylinder. Most likely the valves were not graduated, but were of the simple on-off type. And as with air-assisted handbrake mechanisms, the air would have been “dumped” once the selector rod was at rest with the gear engaged.

Cheers,

[RK215]

I have recently obtained a slightly earlier brochure for the Royal Tiger, dated September, 1950. If anything, this makes an even bigger feature of the air-assisted gearshift than the July, 1951 issue. An acceleration curve is shown and it is claimed that the gearchange is twice as quick as with a conventional gearbox. The pictures show the outline of the air-assistance unit more clearly than is the case for the later brochure, but the internal workings are not revealed. There is a cutaway illustration of the gearbox itself, albeit without power assistance unit. This seems to be the “standard” diagram that Leyland had previously used in Tiger and Titan publicity material. (Actually, essentially the same diagram appears to have been used in later literature, even after Leyland redesigned its 4-speed synchromesh gearbox.)

It seems reasonable to suppose that the Royal Tiger was fitted with the air-assisted synchromesh gearbox from its initial release in April, 1950. Even so, I have a brochure for the Leyland-MCW Olympic dated April, 1950, and this makes no mention of the air-assisted gearbox, nor is it apparent in the illustrations. The original Olympic used the same mechanical components as the Royal Tiger, but was announced a little ahead of it, late in 1949. (The Olympic Series II, dating from circa 1955, used Worldmaster components.) So considering the Olympic/Royal Tiger as a single model family, the air-assisted gearbox was not an original release, but was evidently added fairly early in its production life.

Even so, it must have been a conscious stopgap or rearguard action from Leyland, considering that many of its export and some of its domestic customers would have preferred epicyclic transmissions, which its competitors AEC, Daimler and Guy could all offer. Leyland’s planning for the Pneumocyclic gearbox surely started soon after the Royal Tiger was in production, maybe even earlier. What is a little curious, then, is that once it was available, it was never made a regular production option for the Royal Tiger. As far as I know, the initial release was for the Tiger Cub, for which a separate suffix number was applied, i.e. PSUC1/3. Then followed Pneumocyclic-fitted Titan PD2 and OPD2 and Tiger OPS4 models, again with unique suffix numbers. (The Tiger OPS2 and OPS3 did not survive into the Pneumocyclic age.)

One can speculate that “official” Pneumocyclic-fitted Royal Tigers were not offered because Leyland did not wish to pre-empt the imminent Worldmaster launch, for which the two-pedal concept was a major feature. Still, as previously noted, that did not stop the sale of “special” Royal Tigers with Pneumocyclic gearboxes. For example, in South Africa, Johannesburg had an early prototype and Pretoria had a fleet.

Cheers,

[Dave Wilson]

t been reading that 1939/40 Annual report of the Melb and Metro 51?

[boronia]

Further to Dave's question re the Panda, my resources claim only one Panda was ever made. But LT got 88 u/f chassis 1937-9 (TF class), which were designated FEC, which I guess was "Flat Engine Cub" (the CR class were REC=Rear Engine Cub), but not Pandas??

[RK215]

Production of the Leyland Olympic underfloor chassis appears to have kicked off in 1949 so:

1) How soon after the War did Leyland get into underfloor development
2) Did Leyland call on the Panda design for the Olympic chassis
3) Was the Pneumocyclic box available when the Sydney OPSU1s were ordered in 1951?
4) Is it known whether Leyland aggressively pushed its underfloor range overseas in C 1950-51?

I don't have definitive information on all of the above, but here is what I know or have deduced:

1. Pretty much right away, although the primary job right after WWII was to restore production, and export as much of it as possible. The horizontal O.600 engine was developed very early on, and was available by 1947-48.

2. Probably in a general sense, although it did a lot of updating of its designs circa 1946-47 which resulted in the OPD2/OPS2 series, and also the BUT ETB1 trolleybus chassis (another very good design of the period). The Olympic and Royal Tiger used essentially the same generation technology.

3. No. The Pneumocyclic was announced later in 1953, as an option for the Tiger Cub. Leyland had previously been anti-epicyclic transmission, having developed its torque converter pre-WWII and its synchromesh gearbox just after. It fitted AEC preselector gearboxes only at customer request/insistence. But it must have seen the writing on the wall, and I wouldn't be surprised if the Olympic and Royal Tiger were designed from the start to accommodate the Wilson gearbox. I don't know when Leyland first started work on the Pneumocyclic, but I would guess around 1951. But it (and the corresponding AEC Monocontrol also announced late 1953) was hardly a new idea. SCG had developed the internal pneumatic direct selection concept, with direct or electric control in the late 1930s, and had applied it to the larger railway and off-highway gearbox sizes. It just remained for SCG to apply the same technology to the smaller automotive-size gearboxes, and that was more-or-less inevitable as soon as post-WWII conditions allowed. Whether AEC and/or Leyland pressed SCG into completing the work, or whether they just picked up on its "natural" timing is unknown to me. The only "new" ideas were Leyland's pedestal and CAV's miniature electric gate.

4. Very much so. And one of its main competitors was AEC. Leyland picked up a very early large Royal Tiger order for Cuba (620 in total), and hordes of Olympics and Royal Tigers went to Argentina and Uruguay. Over 6000 Royal Tigers were built by the time it ceased production during 1955. The Royal Tiger comprehensively beat the AEC Regal IV in the export market, then Leyland sealed its "win" by doing an early update (the Worldmaster) to what was already probably the best British underfloor chassis. AEC didn't do its update (to the Regal VI) until late 1960; by then it was too late. Notwithstanding the customary commentary about lack of a rear-engined double-deck chassis being AEC’s undoing, I think it more likely that AEC's fate was sealed in the Regal IV vs. Royal Tiger "battle" of the early 1950s. True, its Reliance did better than Leyland's Tiger Cub in the UK domestic for a while (until the Leopard PSU3 in 1961), but that may have just hidden the underlying situation and inevitable end.

Cheers,

[Dave Wilson]

Thanks .

[Herbert]

I'm keen to learn more about pre-Bourke St bus deliveries (ie how many were AECs in any case?) and more about the alleged dispute between Bell and AEC's agent. If AECs were chosen, at that stage wouldn't they be more likely to be Regents with 7.7l engines & mechanical pre-selectors as per DRTT, rather than Regent IIIs?

Some other possible factors regarding choice of marque may include tram-replacement schemes in the UK which Bell may have come across in his 1935 tour - were there not instances where Leyland torque-converters were seen as providing an easier transition for tram drivers to omnibus drivers?

As for Risson & AECs, I wonder what impact his military service had on that, particularly in the Middle East where, according to AEC's own Contribution to Victory that marque was held in very high regard by officers of Risson's rank.

[Dave Wilson]

Hi Herbert

next issue of Australian Bus will deal with MMTB 1935 -40. Keith Kings and myself. Heaps of photos.

[RK215]

Thanks very much RK 215 - do you think the 1939 MMTB order is likely to have been a Panda? the report does refer to a "pancake" type engine suggesting the LT TF class type chassis as mentioned by Boronia.

Here, I think, we enter the realm of speculation. With the Tiger FEC and Panda, Leyland had demonstrated underfloor-engined technology that it could have used for a production export model. With the Gnu, it had also indicated its interest in transit type chassis with extreme front entrance. But even more so, Leyland was quite early with transit-style trolleybus chassis, and as far as I know had built more of these than any other UK manufacturer. Against that background, my pick for the most likely form of an export underfloor-engine chassis in 1939 would have been two axles, extended front overhang, wheelbase around 16’6” and overall length around 32 feet - or the motorbus counterpart to the transit version of the TB5 trolleybus. It might have had the torque converter transmission. Given that LT’s Tiger FEC fleet had the AEC air-operated preselector gearbox that might have been fitted had MMTB so insisted. But it’s only a guess.

The Gnu and Panda took the 3-axle form only because of the restrictive UK regulations of the time, wherein 2-axle single-deckers were limited to 27’6” overall length. Yet the Gnu not only presaged the Bedford VAL, but also the trambus layout, which didn’t surface again in British practice until the Guy Victory Trambus model of the late 1950s. And the Tiger FEC and Panda probably created post-WWII expectations. Many UK operators undertook only limited single-deck bus fleet renewals in the late 1940s, awaiting the arrival of the expected underfloor models. The same may have been true of many non-UK operators. As an example, I recall seeing an Auckland Transport Board (blah) report from circa 1946-47 in which it called out the American-style transit bus as its desired vehicle for tramway replacement purposes. It made the comment that similar trolleybus chassis should be readily available from UK builders; it might be a while before suitable British motorbuses were available. It did note, however, that the British motorbus, with diesel engine and fluid transmission, was a very efficient unit. At the time, many North American buses were still gasoline powered, and many still had manual transmissions, the torque converter type being relatively new. And even the combination of the Detroit Diesel two-stroke engine and torque converter transmission must have seemed quite fuel-hungry. blah opted to await the availability of underfloor-engines motorbuses before placing any large orders, whereas it was quick to order transit-style trolleybus chassis.

Regarding the AEC vs. Leyland debate, I suspect that a poll of 12 different people is likely to elicit 13 different responses. AEC certainly did get it right in respect of the fluid flywheel/Wilson gearbox combination and air brakes, although that combination was probably as much LT-driven as AEC-driven. Leyland miscued quite badly on that front, yet one cannot overlook the fact that many UK operators continued to specify synchromesh (or constant mesh) for their urban buses well into the 1960s, and that AEC had to add a synchromesh option in the early 1950s. Some operators even specified vacuum brakes into the 1960s. (First job of the morning in the engineering offices of those operators must have been to buff-up those metaphorical rear-view mirrors!) Leyland seems to have done better in engine design terms – for example, I think that the O.600/O.680 family would usually be seen as being better than the 9.6/11.3 and AH590/AH690/AH691 families.

Cheers,

[Dave Wilson]

Thanks again RK 215. I note that torque converter transmission was available at least as early as the Leyland TD-3 model . When did the first preselector appear - was it with the early STLs? Were air brakes and air actuated preselect boxes introduced with the prewar RT or STLs? Did Leyland therefore resist the preselector gearbox as an option because of its torque converter transmission.

[RK215]

The approximate chronology was as follows:

1930 – Daimler introduces on its bus chassis the combination of fluid flywheel and Wilson gearbox with preselective control.

1931 – AEC starts using Daimler-origin preselector gearboxes.

1934 – Leyland introduces its torque converter transmission, based upon Lysholm-Smith patents.

1934 – AEC starts manufacture of its own preselector gearboxes.

1939 – AEC introduces the air-operated preselector gearbox to bus applications with the early RT. It had previously experimented with vacuum operation, and the air-operated gearbox had been used earlier than 1939 in railway applications.


This shows that AEC and Leyland followed quite different pathways when it came to solving the problem of simplifying gearchange operations. Leyland’s approach was more radical, essentially eliminating gearshifting almost completely.

Up until 1939 at least, Leyland, having chosen its pathway, had little reason to reconsider, except where customers like LT required something different.

After WWII, Leyland did not offer the torque converter option on its buses. A few such transmissions were built for railcar applications, but in 1953, when the rail traction division of BUT was formed, the latter organization adopted the SCG direct-selection Wilson gearbox as its standard, replacing both the Leyland torque converter and AEC air-operated preslector types that it inherited. Whether that was technically the best choice is debatable, but given the commitment to Pneumocyclic/Monocontrol on the bus side, it was probably inevitable. A few years later, the Lysholm-Smith transmission was reintroduced to British railcar practice by Rolls Royce, with its license-built Twin Disc models.

By 1945, what was perhaps just discernible in 1939 had become very evident, and that was that most of Leyland’s customers, domestic and export, did not want the torque converter transmission. Here is where Leyland major an error of judgment, I think, in putting all of its eggs into the synchromesh basket. It would have done better to offer an air-operated preselector option on the PD2/PS2, etc. range. In any event it had done the basic engineering for the LT RTL and RTW models. Setting up for in-house production – rather than buying from SCG or AEC – should not have been too difficult. Even had it been a bit hesitant in 1945-6, around 1948 Guy acquired an SCG license and offered the preslector option on the Arab III, which then meant that all three of its significant competitors in the heavy-duty bus field

As a counter-argument, one can point to the sales success of the Olympic and Royal Tiger as an indication that the synchromesh transmission was hardly an inhibiting factor. But then how many customers, particularly those not big enough to demand special treatment, bought these models in spite of their transmission, simply because they were otherwise very good? Evidence of that is that its Royal Tiger customers flocked to the Pneumocyclic-only Worldmaster when it was released, and to the best of my knowledge, none asked for special fitment of synchromesh transmissions.

The curious thing is that at the time that Leyland was abandoning the Lysholm-Smith transmission for buses, it was set to become the new standard for North American city buses, courtesy of GMC and Spicer. The GMC V-drive version (including an overdrive variant) lasted until the late 1970s, when it was superseded by the Allison V730. Quite a few other bus/bus transmission builders used the Lysholm-Smith transmission at various times, too, including I think FBW, Fiat, Scania and ZF. So Leyland had pioneered the use of what was to become a successful idea, but not one that appealed to most of its customer base. Post-WWII, those that wanted it had to ask for special variants. I think that Leyland fitted Spice torque converter transmissions to Olympics from as early as 1950, which is perhaps a little ironic.

Cheers,

[Dave Wilson]

It would seem that AEC had access to the Daimler preselector because of its partnership under the ADC banner. This partnership of AEC-Daimler, I think was dissolved in 1931. AEC manufactures its own preselectors from 1934 (presumably with LT orders for STLs as impetus) and moves into air actuated preselecs in 1939 for the RTs. Its got me curious now as to what brought about dissolution of ADC.

The Melbourne Tramways Board had a number fo ADCs delivered in the late 20s and one single preselector was acquired in 1935 - a Daimler COG -5. The Chairman of the MMTB allegedly fell out with the Australian AEC agents and no more preselectors (and no AECs) were acquired until 1951. I wonder if the fall out was over rights to or cost of the preselector box.

Did Daimler, therefore, ever utilise the air operated preselector box or did it persist with the mechanical/hydraulically assisted versions

[mrobsessed]

The AEC synchro boxes fitted to Reliances (if they were the same ones intended for the Regal IV) were a nice box, with about the same shift effort required as the Leyland box fitted to the Leopard L1. The gate was very close together with reverse at the top and a crawler at the bottom left side of the H.

[Dave Wilson]

I drove L1 Leopard ex Punchbowl 4489 from Blacktown to Tempe in 1986.
from memory it had a very cramped driver's area. Steering was very heavy and reverse gear position was diabolical. In fact it almost got to the stage of not moving the bus due to the reverse gear problem. Then suddenly it clicked in and we were right. On the road it performed quite well, all forward gears being quite positive to find. The bus also had grunt. On the other hand, driving ex Pioneer Reliance 634, I found the gear positions less positive but steering very negotiable.I found the same with an ex Canberra, ex Red Top Reliance'I had a go at' in the late 70's.

4489 was sold as a caravan to the Central Coast, regrettably.

[mrobsessed]

Dave, you'd probably remember the ones I am talking about at Dion's, ex-Rowes group. They were beautiful buses, fast (especially with a Beattie's or Hill's bus on their tails) smooth and with good bodywork. The same gearboxes were fitted to most of Rutty's Royal Tiger Cubs and some of those ex-UK John J. Hill, later Smithfield re-bodies (the ones they didn't destroy by putting pneumos in). They were worse with worn synchros than as constant mesh.

[Dave Wilson]

I only remember them laying around out of use, never rode one.

[boronia]

The curious thing is that at the time that Leyland was abandoning the Lysholm-Smith transmission for buses, it was set to become the new standard for North American city buses, courtesy of GMC and Spicer. The GMC V-drive version (including an overdrive variant) lasted until the late 1970s, when it was superseded by the Allison V730. Quite a few other bus/bus transmission builders used the Lysholm-Smith transmission at various times, too, including I think FBW, Fiat, Scania and ZF. So Leyland had pioneered the use of what was to become a successful idea, but not one that appealed to most of its customer base. Post-WWII, those that wanted it had to ask for special variants. I think that Leyland fitted Spice torque converter transmissions to Olympics from as early as 1950, which is perhaps a little ironic.Cheers,

Back in the mid 60s I had a drive of one of the ex-MMTB TS7Cs at Lithgow, with a view to purchasing one. While the performance on flat ground was reasonable, it was absolutely useless on anything more than a mild gradient. I can also remember a couple operated by Tamarama Bus Co a few years earlier struggling on the hills around Bondi Junction and Bronte. Perhaps Leyland's design was not very efficient in terms of power transmission, without any form of gearing to better use the limited engine output. I assume this would be why many of the buses fitted with this from new later got manual box upgrades.

Perhaps it was subsequent customer fear of fluid transmissions that turned them away from "experimenting" with another version so soon after. I would suggest that in the late 40s/early 50s traffic congestion was nowhere near as bad as today, and the need for a more expensive (to buy and maintain) gearbox wasn't a high priority.

[Dave Wilson]

Boronia - I'm pretty sure none of the MMTB half cabs (or dds) were upgraded to constant mesh but certainly the Sydney deckers were.