For the past couple of years, RV manufacturers have been proposing an innovative solution to ICE and EV range loss from towing a heavy camper. Airstream, Dethleffs, Lightship, and Pebble all believe in a future where trailers have electric drivetrains, thus helping their tow vehicles reach their destinations more easily and with more range. It’s a new technology, but an old idea. Back in the 1960s, Land Rover and a couple of British trailer companies experimented with the idea of a powered trailer. These essentially PTO-driven trailers had shafts and differentials, ensuring the trailers weren’t dead weight behind the truck. They also turned a four-wheel-drive truck into more or less a six-wheel-drive articulated truck.
The powered trailer is a weird part of motoring history. These trailers were built to solve a problem that has plagued trailers since the dawn of towing. When you tow a trailer off-road, it’s unpowered heft that your tow vehicle has to pull through the terrain. That’s fine until that giant weight gets you stuck somewhere. That creates a mess where you have to free both truck and trailer, which could be extremely difficult if you’re somewhere remote.
Powered trailers from British companies Rubery Owens and Scottorn Trailers Limited were supposed to solve this problem. These trailers connected to the Land Rover 109 and then later, the Land Rover 101 Forward Control British Army truck to create one articulated 6×6 truck. However, these trailers didn’t catch on, and now they’re an obscure piece of history.
Military Duty
These trailers and the trucks that towed them are examples of innovations created because of military demand and are closely related to the development of the Land Rover 101 Forward Control. According to the book Encyclopaedia of the Modern British Army, the development of the 101 Forward Control began in 1967. Back then, the Ministry of Defense had a desire for a heavy-duty truck that could be deployed by an aircraft and could carry either a 1-ton load or eight soldiers.
At the same time, the Army also wanted the truck to be equipped with a power take-off so that the truck could haul a powered trailer, effectively making a 6×6 vehicle. That trailer had a 1-ton capacity as well. The Army’s idea was that the Land Rover could carry soldiers and their gear while the trailer would carry the 105mm shells for the 105mm Light Gun carried in the consist.
As the Encyclopaedia of the Modern British Army continues, the development of the 101 Forward Control was carried out by Rover as well as MVEE. Prototypes were built in 1968 and 1972 before full production began at the Land Rover factory in Solihull in 1974. The Land Rover 101 Forward Control is a pretty awesome truck in its own right. The truck derives its name from its forward control configuration as well as its 101-inch wheelbase. Making the truck a forward control vehicle helped save space when the 101 was in an aircraft. That short wheelbase also helped the truck traverse rough terrain.
Power came from a 3.5-liter Rover V8 rated for 135 HP and 205 lb-ft of torque. Those ponies were sent through a four-speed manual to a full-time four-wheel-drive system that featured a vacuum-operated center differential lock and a two-speed transfer case. Other gear included 12- and 24-volt electrical systems, live axles, and recirculating ball steering. Put another way, these were built to be durable gun tractors to serve the British Army through existing and emerging conflicts.
Reportedly, Land Rover 101 Forward Controls were given tasks such as towing part of the British RAF Rapier guided missile system, hauling 81mm mortars, and towing the powered trailer with its equipment. Other 101FCs found roles as radio vans and even ambulances. Despite the truck’s versatility, just 2,669 101FCs were built until 1978. Thankfully, these trucks were sold as surplus and have ended up in the hands of private individuals. In their place were new Land Rover Defenders and Pinzgauer trucks.
But what about those trailers?
The Powered Trailer
Developed alongside the trucks were the trailers that the PTO units from the trucks would power. Rubery Owen and Scottorn Trailers Limited both created powered trailers that could be hauled behind a Land Rover with a PTO. I could not find much history on Scottorn Trailers aside from the fact that the company goes back to the 1960s and as of today, it no longer exists.
Rubery Owen still exists and was started in 1884 by John Tunner Rubery and brothers Thomas and Samuel. The company is known for producing steel parts and components for a vast variety of industries from roofing to bicycles to cars. At one point, Rubery Owen had a portfolio of over 12,000 different parts, which required 15,000 workers across 88 subsidiaries in five continents to assemble.
For the most part, these trailers were nothing special. They featured welded steel chassis, and steel cargo boxes, had roughly 8-foot beds, and a total length of around 10 feet. The trailers from both manufacturers were made to haul 1,500 pounds. Scottorn published a brochure advertising its Bushmaster power trailer as turning a Land Rover into a 6×6 vehicle. The backside of the brochure touted the trailer as being able to carry cargo, but also for applications such as a portable generator, a 200-gallon fluid tank, a portable welder, or as a portable compressor.
What changed the game was how the trailer moved. Attached to the power trailers was a Land Rover axle with a differential. That axle then connected to a central PTO coming off of the Land Rover tow vehicle. Land Rover FAQ, one of the only resources on these trailers, describes how the trailers worked:
The trailer drive for the trailer was a PTO that attached to the rear PTO hole on the back of the transfer box. From there two propellor shafts connected at a strut bring the drive to a coupling that passed through the rear crossmember. The trailer connects to the 101 via a male bit that fits into female receptor on the crossmember. The two are held together via a perimeter chain system. The trailer tongue is articulated to allow the trailer to pitch up and down, rotated left and right and twist clockwise and anti-clockwise in respect to the 101. This is a “treble hooks joint nose coupling”. A Scottorn Bushmaster advertisement claims that this coupling allows articulation 60 degrees in all directions. To achieve this, there are two universal joints betwen the male coupler and the solid part of the trailer tongue. Then the drive passes through a bearing, and through two more universals to get down to the differential. The differential is the same Salisbury as found on 101FCs. The tires and rims are the same too.
Here, our David Tracy provides an image of what a central power take-off looks like, at least on a Jeep:
Now, you might have seen that brochure and feel like pointing out that the trailer is not attached to a Land Rover 101FC. As Land Rover FAQ explains and the brochure shows, one Scottorn version of the powered trailer was first developed long before the 101FC for the Land Rover Series IIA 109. Still, the trailer operates on the same concept. Reportedly, prototype versions of the powered trailer were able to be used only in low range, but later versions would be able to be used with both speeds.
It’s noted that the trailers worked their best when the 101FC and trailer combination traversed situations where an unpowered trailer would bog down, such as sand. Where an unpowered trailer got stuck, the power trailer got the rig through. The power trailers also had quirks. Allegedly, one time a 101FC hooked up to a power trailer attempted to make a sharp turn. The trailer overpowered the truck, tipping it onto its side. Apparently, recovery was as easy as putting the truck in reverse and using the trailer to pull the truck back onto its wheels.
Here’s a power trailer in motion:
It is unknown how many of these trailers were built or for how long. It is known that the powered trailer was dropped from the official specification for the 101FC, and reportedly, they did not see a ton of military action. The fact that there are barely any pictures at all of these trailers also suggests a low production count. No videos exist of Land Rover power trailers, either. One potential explanation for the demise of these trailers was the aforementioned rollover. Another explanation was an alleged high cost of manufacture. Neither has been confirmed.
What I do know is that the Land Rover 101FC wasn’t the only truck to get a powered trailer. The ZIL-137 6×6 Soviet military truck also had a massive four-wheeled powered trailer that effectively turned the rig into a 10×10 truck. I’m sure there are others out there.
Could This Be Useful Today?
While it’s unlikely you’ll ever see a Land Rover power trailer, perhaps this could be an idea for today’s technology to take advantage of. I’ve already written at length about RV companies that are putting EV powertrains in campers. In these cases, the manufacturer is trying to save range that would normally be lost from towing a large trailer.
However, I could see this working for off-road trailers, too. The use of EV technology would mean that you don’t have to drive a tow vehicle with a PTO. It also means you could engage the trailer’s drive system only when you get stuck, potentially reducing the hazard of the trailer pushing your tow vehicle over. Or, perhaps as alleged above, maybe the trailer could even help you free your rolled 4×4. Powering an off-road trailer could mean your trailer is just as capable as your off-road vehicle, which sounds sweet.
Either way, Land Rover’s short affair with powered trailers is fascinating. They were built to solve a problem that exists today, but for whatever reason, just didn’t work back then. Could it work today?
While the article mentions the trailers being used with the 101FC and the 109, the two photos and the diagram from the Scottorn leaflet show the trailer attached to an 88″ Series II or IIA.
Interesting Things I Know About The M561 Gama Goat
My first association with the Gama Goat began in 1976 in Bamberg, Germany. The unit I was assigned to had literally dozens of them. My Survey platoon had three of them, all built-up with a wooden shelter on the cargo trailer. This allowed us to keep valuable equipment secured.
The Gama Goat was very maintenance intensive and when done properly were fairly reliable. To ignore any of those steps was to invite disaster. One point was a series of access ports on the bottom of the sealed compartments. These allowed access to u-joints, suspension components, and even changing the oil in the engine and drive train. These needed to be opened up after every major roadtrip or field exercise. Of course opening them up meant that the seal got a lot of use and often failed and were always on back order.
Changing the oil required a very specific amount of oil of course. Combine that with oil dispensed from a 5 gallon pail meant that amount was seldom optional. Oil filters were also on back order meaning they often didn’t replaced when needed. Checking and filling of the drive line components was a huge pain in the ass, due to inaccessibility.
Tire pressures were also critical, but guess what item of equipment wasn’t available other than at the Battalion level? A freakin’ tire gauge!
The washing of the Gama Goat was very labour intensive, requiring the removal of cushions, etc. Then off to the wash rack where high pressure hoses blasted every surface internal and external, resulting in gallons and gallons of water to accumulate in the hull, which then had to be drained or pumped out with the bilge pump. Oh, and if there was some errant piece of trash floating around, the pump would become blocked, requring a trip to a higher level of maintenance to repair it.
And while I’m thinking about it, those access ports and empty spaces below deck, the same applied to the trailer portion. Forget that, and you could end up with a very tail heavy water logged cargo box out back.
On a positive note, performance was good, fuel mileage acceptable, and the electrics throught were pretty much problem free.
And finally, while that Detroit diesel would burn gasoline, it was in a very limited amount. More than a gallon or so out of 40 and you would be shooting blue flames (literally) and speeds far beyound anything the desingers ever had in mind. Ask me how I know!
If I think of more, I will pass it along.
Lots of PTO powered trailers on farms, and for logging. In France they mainly seem to date to the 1980s for collecting wood, and still work — it is not fancy engineering.
Been in a tractor getting wood with one — with about 10 tonnes on a slippery clay road. When started to slide alarmingly, in went the PTO and up we went with no problem.
The owner made sure to disengage the PTO as soon as the surface improved, he was worried about the diff on the trailer…
For farms it is mainly liquid muck spreaders which have them — heavy when full and the work is mainly done in winter.
While these are fine and dandy, they don’t give you any more power. Some other fine people had a different take, and built these crazy contraptions: https://www.curbsideclassic.com/blog/vintage-trucks/truck-history-freightliner-power-dolly-a-helper-engine-on-a-second-semi-trailer/
Yes. The Sherp Ark 3400 10WD.
https://youtu.be/cqdXeg48FSQ
I have seen guys build homemade versions of these trailers for farm use. If the trailer bogs down, you can just pull the lever and activate the PTO.
Earlier tractors rand the PTO from the transmission so they only worked while in gear and had no freewheeling (or overrun) so if the PTO was on and you tried to stop, your implement could push you. Later tractors incorporated an overrun clutch and ran the pto directly from the engine.
“Allegedly, one time a 101FC hooked up to a power trailer attempted to make a sharp turn. The trailer overpowered the truck, tipping it onto its side”
That was more common than you think, my dad saw it happen quite a few times in his time in the army in the 60’s. He saw a few Privates put their 109’s or Unimogs on their sides when learning to drive.
I’d say that these are what is mentioned in the video, driven trailers, since they are powered by the tow vehicle and have no power source of their own.
There’s a little bit of the powered trailer in this video at around the 8.35 mark:
https://www.youtube.com/watch?v=DJzz8aU3Ztw
Plus all manner of PTO accessories being used. Essentially turning the Land Rover into a tractor.
Love all the guys in white shirts and ties, especially the one greasing earthmoving equipment who one-ups the rest by wearing white coveralls!
That was the first thing that I noticed too!
Plus no PPE other than gloves and tucking your tie into a gap in the buttons of your shirt.
That Land Rover 101 Forward Control! I love beautifully executed artistic styling as much as anybody, but what an almost perfect combination of Less is More, an instinct for good proportions (e.g. the sides and rear of the load bed) and functional beauty. Yum!!
Our garbage trucks use a PTO system. Instead of a system for powered accessories, the engine runs a smaller shaft that runs the hydraulic pump for all the hydraulic functions of the compactor (ejector blade, sweep blade, tote lifter, kick bar, winch cylinder, etc). These setups sometimes require the pump system be shut off before driving lest one overrev the pump and cause mechanical failure.
Not the coolest application I’ve ever seen for a Land Rover PTO, however. That would be an ice cream maker.
I have seen one used to power a circular saw, at least 1 metre in diameter.
Temptation was to rev the motor to really get it spinning — logs screamed to the high heavens as they went through…
And my brother as a farm manager, had a Landrover 90 with a PTO, and with a little bit of being young stupidity, managed to use the hand throttle with rachets as a cruise control…
Doing Laguna Seca with a Goat
In the fall of 1979 I was stationed at Fort Ord, California which of course is/was next door to Laguna Seca raceway. My job in the Army was that of Chief Surveyor and we did a lot of training up and down the state of California to include Fort Irwin and of course our own backyard at Fort Ord. Truth be known there really wasn’t not much left to survey on post but it was a good place to go out and goof off all day while staying out of trouble. This included driving up and down tank trails, creating our own trails and just in general burning diesel fuel for the fun of it.
One day we found ourselves in the extreme southeastern corner of the post when we heard the sound of high performance engines running up and down the scale, some baritone others nearly soprano. It was an awesome sound and we immediately went to investigate. Driving our trusty Gamma Goats across barren scrub we popped over a hill and there laid out before us in all its early beauty was Laguna Seca. This was of course well before it became an international fixture on the race scene. Brightly colored flashes of light preceded these awesome sounds as small agile cars slithered around the corners. There was a heady aroma of half burnt racing fuel and the sharp almost toxic smell of castor bean oil that was a incredible mix with the dry sage and desert dust.
We parked our goats above what I later learned was the infamous corkscrew and watched for well over three hours. Finally just as the less mechanically inclined of my surveyors were beginning to push for me to take them home, the last of the cars left the track. After a short while we observed them being loaded onto trailers and beginning to follow the gravel road away from the track.
I contemplated the situation for all of five minutes before deciding to take the plunge and dare the gods to turn on me. I signaled for my drivers to fire up the goats and with my goat in the lead, we scrambled down a rugged escarpment and onto the track at the base of the corkscrew. I radioed everyone to take the goats out of six wheel drive and drive with “all due caution!” Now Goats won’t drift but they will howl and believe it or not are actually fairly stiffly sprung which in turn meant that if you had selected the proper gear going in, you could come out of a tight turn with a big shit eating grin on your face.
As we roared past the pit area belching black diesel smoke we were horrified to find that we weren’t alone at all. Rather there were a few stragglers and track marshals wandering around the pit area. As we bellowed past they gave us an astonished look and began madly waving their arms. I figured our best course of action was to continue on around the circuit and be a hasty retreat the way we had come in.
As we began the plunge down the corkscrew I was amazed to see a corner worker furiously waving a green flag at us and indicating that we should continue on the track. We ended up making three full trips around the circuit before finally departing for the hills. In the months ahead, I revisited the track several times but never had the nerve to try another lap. Wish I had.
More Sea Stories available on request!
PS For clarification, I was dual service, serving 9 years in the Corps before transfering to the Army to save a marriage. Fiftyseven years later, it was a good trade.
I think for off-road campers it could make a ton of sense with a BEV drivetrain, especially with an integral solar setup and or a ranger extender ICE engine.
However Trailer weight is a big deal, especially off road. I’d go with the lightest battery pack I could get away with for such a thing.
I believe powered trailers are a pretty common sight on forestry tractors, same principle just bigger
Sidenote that has very little to do with anything. PTO – Power Take-Off. PTU – Power Transfer Unit (i.e. a transfer case for transverse AWD cars). I got schooled on mixing up those terms once. This article doesn’t make that mistake, but I have in the past called PTU’s PTO’s. Different animals.
Let me be the 1st old Marine to introduce you to the Gama Goat https://en.wikipedia.org/wiki/Gama_Goat If you want more personal details, just ask!
(raises hand)
Tell us! It’s cool stuff—and personal experience is even better.
(also raises hand)
Seconding TOSSABL’s request! The coolest vehicle I got to play with was driving an old M35A2 deuce-and-a-half in Kuwait. That shift pattern has to make sense to someone; but I’m not that someone yet…
While people always gush about German engineering, I am frankly more impressed with the audacity of British vehicular design philosophy. Sure, you can lampoon Lucas Electrics as the runt of the litter. But in general, British stuff will indeed work to task. More or less as intended. Sometimes the less rather than the more of course. Still.
My understanding is that, while British stuff often works to task, that often wasn’t the case with British workers—depending on the task
to be fair, with the habit of drinking small beer all day continuing as a tradition long after the water was safe to drink, it’s kind of understandable. And, if I had to build some of the shite BMC workers toiled on, I probably wouldn’t have much will to live, either 🙂
Small beer only helps so much. It’s a pint of the real stuff come whistle time.
I think the combination of tail wagging the dog handling and high cost and complexity killed the PTO driven units. Increased helicopter lift capacity was also a factor. Both the Landrover 101 and the 88 Lightweight were designed with removable body panels to keep the base vehicle within the lift capacity of a Westland Whirlwind and then the British bought CH47 Chinooks with a 28,000lb lifting capacity and could sling load a Scorpion light tank.
surprised my dad never tried this with the back half of a late 60s c10 that became a trailer.
Also the idea of the Hägglunds bandwagon fron the 70ies 😎
That was a much more successful concept, and updated version is still available and widely used.
I loved these things! My brother used to be in the UK Royal Marines, and my favorite part of visiting the base for “family day” was that they’d drive you around the site in one of these. I’m sure they didn’t move quickly, but it sure felt like they did!