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Driving a Universal LP2 [Aust](Bren Gun) Carrier.
This article, as with my previous "driving AFV" ones is written for those who have never had the experience. Some carrier owners are probably not going to be happy with what I say as this is a warts and all description. Everyone is entitled to their opinion. I welcome any contributions for this website on this subject.
The Universal Carrier is popularly known as a "Bren Gun Carrier". Strictly speaking, the real "Bren Carrier" is one specific variant in the carrier family of vehicles which ran from the 1930s until the early 1950s and was itself a development of the earlier (WW1 and onwards) artillery carrier/prime mover class.
The subject of this article is the LP2 fitted with a Ford side valve V8 petrol engine rated at 85Hp, 239ci. Weight of the vehicle is approximately 4 imperial tons. So you have a power to weight ratio of rougly 21 Hp per ton, which is not untypical of an armoured vehicle of that era, for comparison, a current passenger car would have around 125 Hp per ton. Not that you can really compare the 2 as the driveline of a tracked vehicle has huge amounts of frictional losses.
The vehicle is reasonably easy to climb on to from most directions. Being open topped situational awareness for both crew and those outside the vehicle is fairly good, except for rearwards and the frontal sector of the gunner's position where the armour is higher. All the usual safety considerations still apply, with the most obvious being to let the driver know what is happening around him, whether "you" are in the vehicle with him or outside of it.
Although fairly straight forward, pre-drive maintenance and preparation should be undertaken by someone familar with the vehicle, specifics would relate to track tension and assessing correct steering and brake control.
To drive the vehicle you enter via the front gunner's position and slide across into the driver's seat, the steering wheel is set too low to allow anyone but the most small and agile to hop straight down into the position. In the process you maneourve your way around the vertical steering column, gear stick and the hand brake lever. The pedals are of a design that you need to visually locate them first so that you can disentangle your feet from the various protuberances which are a part of the design, the pedals are spaced differently to modern automobile pedals. Once you have done this and have seen the layout, you are okay from then on. Unlike the Blitz truck family, carrier pedals are in the conventional order.
Requirements for starting the carrier may vary depending on model and state of preservation, but basically consists of setting the choke - located over the driver's left shoulder, setting the hand throttle (if the condition of the individual vehicle and temperature requires it), hand brake on, and gearbox in neutral.
The ignition switch, just like the Centurion, appears to be visually identical to a bakelite domestic light switch. There is a starter button on the dash. The engine takes quite some time to warm up. Being that the driving position is immediately in front of the engine, with the radiator close to the driver's left arm, means that there is quite a bit of fan and mechanical noise.
Once underway inital steering is by way of a steering wheel controlled, cam actuated, sliding centre axle, to effect track warping: this is so that there is no power wastage because of steering corrections whilst running down a straight road. Very sensible. Further turning of the steering wheel, by way of a system of rods applies the brake on the approriate side in order to tighten the turn. Braking is by conventional pedal.
The downside is that the design has no power assist so when driving on a road that does not have a constant camber eg. a bush track, a portion of the weight of the carrier must be held by the driver in order to keep the track warped and thus the vehicle heading where intended. Then when the grounds slope changes the other way, you have to wind the steering wheel through up to 1 turn to warp the track in the opposite direction. Whereas with a normal tracked vehicle you just give a pull on the steering lever every so often.
It is a tiring and high work load design. The whole mechanism, unless conscientiously lubricated and cleaned of dust and dirt (in non-army use this is unlikely) sticks, add to this the need to hold the weight of the vehicle through the steering wheel and you have a piece of engineering that until the advent of power assistance was not desireable. The German Kettenkrad uses a similar concept, but the front wheel is used for corrections and the track brakes for harder turns - there is no warp steer, and thus the Kettenkrad is much easier to drive.
When reading the above comments it is necessary to keep in mind the time period in which the carrier design came about, the severe monetary problems facing the British military, (political disinterest in armoured vehicles) and the technological limitations of that time.
Luckily for carriers, they attract a following due to their appearance, history, simplicity, size and probably most necessarily their post war use on farms as donour objects for engines and mechanicals. This meant that until the 1980s it was still fairly easy to find derelict vehicles that could be restored, mostly always missing their engine, gearbox and radiator. Quite commonly they also had sections of armour missing. The person who cut out the armour usually discovered that it had strange characteristics when hot cut, cracked when welded, was the wrong hardness and generally this ruined its suitability for the intended purpose.
As one bloke said to me 'the poms spent 30 years developing the carrier and just as they had finally go it sorted out it was obsolete'. I will however point out that from this design and the lessons learned from it the APC came about as a consequence, sometimes they need to get it wrong to learn how to get it right! Having said that, the modern APC is actually a re-think of the WW2 British habit of de-turreting obsolete US tanks, particularly the M3 Stuart series and adapting them as carriers. If you examine the steering differential of an FV-432 or M-113 you will see a direct decendant of the US light/medium tank steering, not the British carrier.
Riding in a carrier strongly reminds me of riding a rocking horse. That long track overhang before the first road wheel gives for a different ride than anything else you will have encountered! It sets up a rocking motion over even slightly rough ground and gives a very pronounced nose up on accelerating/nose down on braking effect. My experience does not indicate any sea-sick effect, more so just a "this is unusual" reaction.
Anyway, back to driving the thing. The gearbox is a "crash" type operated by long rods, so the gearchange technique is an aquired art just like with the Centurion. Due to the rods, the normal technique of feeling for when the gears are ready to mesh (as you would do in a Blitz or any vehicle with a crash box) doesn't seem to work, more a case of when all the noises sound about right, giving a good solid push or pull on the gearstick to make the change happen. Oh, double clutching is necessary. The gear stick mechanism itself has a lot of play in addition to the rod flex and tends to be quite "floppy".
As soon as you push the clutch in you are aware of the change in the background noises, you now hear the clutch throw out bearing at work.
The rocking horse ride is there, without being unpleasant, as is the track noise and drivetrain noise, you fairly quickly adjust to the fan roar. The brakes are what you would expect for a non-hydraulic system, but are assisted by the inherent drag of the driveline, thus the vehicle will quickly lose momentum on flat ground, almost instantly on an uphill slope. Of course, downhill is another matter altogether and the rule of keeping the vehicle in a low gear applies so that engine braking is available.
When it comes time to take a corner (anything other than a gentle steering correction) you turn the steering wheel to the point where the braking function is applied. Once you reach the point where the brake is applied, there is not much movement left in the steering, perhaps 30 Deg., between no braking and maximum braking. It is a brute strength application and it does not tend to elegant. Should you be on a stretch of road that has a bend that is just past the warp steering limit or a combination of side slope and bend then you have to continually apply brake steer. The downside, because of the braking effect, is a choppy series of jerks to get around the bend. Although this effect does occur with normal brake steer track vehicles, their differential steering is more suited to the application and is usually smoother as a result. I daresay when the vehicle was new, with dust free linkages and a crew who had nothing better to do than keep it in perfect condition, it could be driven with finess.
The adaptation of the Ford engine, (which had been designed for normal automotive use) into an AFV caused significant over-heating issues, which were only ever partially solved. It thus pays to be mindfull of the temperature gauge. You expect to see a carrier motor running on the high side of the temperature range, this means that there is not a lot of safety margin left should the engine have any issues (eg, age and sediment build up etc). Keep a wary eye on that temperature guage! The vehicle owner should have a good idea of the normal running temperature of his vehicle and what he is prepared to accept as maximum operating temperature. Ferrets as an example operate very high temperatures as a matter of course. In Aussie summer conditions, mine runs at around 200 Deg. F, ie., only 12 Deg. F below atmospheric boiling temperature. It rarely runs much below 160 Deg. F even in winter. As with most cooling systems, the pressure seal provided by the radiator cap does raise the boiling point a few degrees. With any of these vehicles, an idle run down of several minutes is a good idea so that the engine is evenly cooled before switching off. This prevents localised boiling within the cooling circuit and reduces the risk of warping.
The Bren Carrier is a quirky little vehicle that has a niche place in history. It is a tiring design to drive. In saying that, it is so different to most vehicles in its ride and handling and the driving technique required that it is one of those things that falls into the "to be experienced" category. They are the "poor man's tank" of the AFV world; although too heavy to move around on the back of a car trailer, they can be moved by medium truck/ medium trailer combination.
Would I line up for another drive tomorrow? Of course. Would I want to spend a couple of years crewing one every day - no way!
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