Mack RS786LST with Fruehauf tanker, Scale 1:13
'Rubber Duck' from the movie 'Convoy'


Mack_RS700L This is my fourth truck in the scale 1:13, and the idea to built this truck came up a long time ago. Actually I have thought about building this truck all since I saw the movie for the first time, many years ago. I think that most trucking fans, find this movie and this truck very special.
Since I now have the experience from three other trucks, I found it the right time to try to realise this old idea to create this, to me, legendary truck; The Rubber Duck, black Mack.
The model has in both ways been easy and hard to built. Easy in the way, that American trucks are much simpler than European trucks, not as compact and complicated. Hard in the other way, because it was impossible to take a piciture of the original truck to check a detail. All informations had to be found in the movie, and on different homepages, made by other fans of the movie, and the truck.
Besides that I have bought a lot of special bricks to make it look as close as possible to its legendary original truck.

I hope that you will enjoy my description of the project, as much as I had enjoyed building the model.

The Movie

First I will make a short resume and description of the movie, to those who do not know it, or need a refresh of the story.

The Movie CONVOY, produced in 1978, directed by Sam Peckinpah, with the actors Kris Kristofferson, Ali MacGraw and Earnest Borgning in the main casts, is one of the best, if not, by my oppinion, the best, trucking movie ever made. In 1976 C.W.McCall recorded the song Convoy which the movie are based on. To make it fit a bit more to the story of the movie, some of the text were changed a bit to this.

The movie begins in Arizona, with the black Mack, driven by the main cast, 'Rubber Duck' highballing over the pass. A while after a Jaguar starts to catch up, driven by the other main cast, Melissa.
The situation is complemented by the song 'Convoy' from C.W.McCall.

Melissa drives up by the side of Rubber Duck (RD) and starts to photograph him, then they meet a police car, which has to go out in the dirt to avoid a collision. RD stops the truck, and the police officer talkes about a heavy fine, but when RD tells the officer that the lady in the Jaguar didnt have any pants on, then the police officer starts to chase her instead.

RD drives along, and soon he cathes up by his old partner 'Love Machine/Pig Pen' played by Burt Young and 'Spider Mike' played by Franlyn Ajaye. The talk on the CB, and races a bit, unfortunately the sherif 'Dirty Lyle' played by Ernest Borgnine, tricks them into a speed trap, and they has to pay a fine.
After that they go into a truck-stop, to get something to eat. 'Dirty Lyle' comes by, and starts to bother 'Spider Mike' and attempts to arrest him for vagrancy. It ends up in a big fight, two more police officers join, and soon the whole cafeteria is ruined, and the 3 police officers lies on the floor.

Movie_clip Movie_clip Movie_clip Movie_clip
The 3 truck drivers, plus some other, which joined the fights, hurry to drive avay from the cafeteria, to cross the stateline, and thereby avoid to get caught by the police. The lady with the Jaguar, are also at the cafeteria, since her car broke down, so she join RD in his truck.

With the cop in their tail, the trucks cross the border to New Mexico, more trucks join the convoy, and more cops starts to chase the trucks.

Dirty Lyle tries to stop the convoy with helicopters, road blocks, etc. but nothing works, the trucks keeps on going.
Soon the army starts to chase the convoy too, but before that, the truckers gets the change to talk to a governor, Jerry Haskins, played by Seymour Cassel, which offer to talk the truckers case and present it to the senate, and thereby avoid the army to blow up the convoy.
Movie_clip Movie_clip Movie_clip Movie_clip

Meanwhile, Spider Mike has been beated and put into jail in Alvarez (Texas), since Dirty Lyle hopes to trap RD to come and free Spider Mike, and thereby get caught by Dirty Lyle.
When RD hears about this, he starts to drive to Alvarez to free Spider Mike, but he is not alone, 8 of the other truckers follow him, to help free Spider Mike.
The city of Alvarez gets ruined by the 9 truckers, and finally RD and Pig Pen runs into the jail house, where Dirty Lyle gets hurt, and they can free Spider Mike.
RD claims that the conflict between RD and Dirty Lyle, now is over, but Dirty Lyle is not satisfied, he wants to beat RD. Again he traps RD, by cutting the other trucks off, and RD comes alone to a bridge, heavely armed by tanks and jeeps by Dirty Lyle. RD tells Melissa to get off, and he hammer down the Mack and highballs out on the bridge. He hides below the dashboard, well protected by the engine. When the trailer is hit by bullets, and the 10.000 gallons of nitromannite explodes, he turns the Mack out the side of the bridge, into the water, and everything turns quiet.
Movie_clip Movie_clip Movie_clip Movie_clip
Subsequent, the governor makes a memorial speech to honor the driver who satisfied his life to a case so important, the governor promices to present the case to the senate. Meanwhile a small bus goes by, where RD sits on the back seat with a patch over the eye, waving to Dirty Lyle, and saying 'Quak Quak', '...who sad a Duck could't swim!'. Dirty Lyle starts to laugh, and realises that he cant beat the legendary Rubber Duck - Ten Four.

The Original Truck


The truck in the movie is owned by Rubber Duck him self (Martin Penwald), under the company name, 'R.D.Trucking - Inc. Albuguerque'.
The truck is a standard American '18-wheeler'. i.e. a tractor with tandem, and a 2 axle semi-trailer.

In the movie a total of 5 truck is used as the 'role' of the black Mack, I have decided to built the one, mostly used in the beginning of the film, when it is still intact.

The Tractor

It is a 1977 model, Mack RS786LST, which was new when they started to shoot the movie, delivered by a dealer in Albuquerque, (New Mexico) specially equipped with a bull bar, and a raised fifth wheel, to accomodate the Fruehauf tanker.
Through the movie the truck was hardly damaged, and finally used to the first scenes in the final bridge scene, but the truck actually survived and was later preserved at a museum.

Here are the data I have found of the tractor.
Mack RS786LST


1977 Mack RS786LST


Mack ETAY676 283 hp "Tip Turbine" turbocharged inline 6, diesel


Fuller RT9510 10 speed Roadranger


220" (frontaxle to center of tandems)


60" from Able Body Company, with cut-out right corner for the exhaust


Mack 38,000# Camelback

Rear axles

Mack 38,000#


"budd" style 10R22 tube-type, black paited rims, with w/2 holes.

The name "Tip Turbine" is a model description of the first attempts to make an intercooler. The problem with a turbo, is that the intake air gets really hot by the turbo, which spoil the efficiency of the engine, therfore they tried to cool this air, by a second air intake, directly bypassing the turbo. Thats why you can see two intake pipes from the air filter on this truck.

The Trailer


The trailer is a standard Fruehauf tanker, with a standard American configuration, i.e. two axles placed in the very rear end of the frame. It gives a good stability, but takes more room in the corners.
Unfortunately I havent found much data of the trailer, I only have the data from the film. In the movie it is mentioned that the trailer carries 10.000 gallons of Nitromannite, equal to 38.000 liters.

Below a few pictures from the movie.

Movie_clip Movie_clip Movie_clip Movie_clip

I hope that I have now given you the necessary background for you to understand why I think this truck is special and in a way deserves to be built.


LEGO model

As I briefly mentioned in the beginning, this model has both been an easy and a hard model to built, compared to my other models.
I have in a way experienced that an American truck is simpler, ment in that way, that all the components are not as compressed and linked into each other as on an European truck, thereby you can concentrate on building one component at a time, attach it to the frame, and then move on to the next one.
On the other hand, it has been hard to find the necessary material and information to built some parts. The truck is so old, that I had to find a lot of data and pictures by truck scrappers. But it has also been a funny challenge.
In regards to the color, the truck has been easy to built, you can find almost any bricks in black, only the chrome parts has been hard to find and expensive to buy, but I think the overall result is close to the original truck.
The trailer was also interresting to built, it should have been in silver, but this is not available in LEGO, so instead I used the new light bluish gray, and I think it is ok. But enough about that, now to the more detailed and technical explanations.

The Tractor


The truck is built as a 6x4 configuration, which means a tandem tractor, with a normal stearing front axle, and two driven rear axles. A typical American configuration, with the axles placed all in front and rear of the chassis. In the front the engine is placed below the hood, behind that the very narrow drivers cabin, and behind that, a large sleeper.


The chassis is built of to longitudinal frame sections, with supports in between. The frontaxle is made as the original with 2 longitudinal leaf springs and shock absorbers, the front wheels can turn and they are equipped with an Ackermann connection to turn the innermost wheel more than the outer to give the right direction when turning.
The two rear axles is equipped with driven tandems, working differential, and propellershaft to the gearbox. The axles are equipped with a Mack Camelback suspension, named like that, because the springs has the shame as the back of a camel.
Above the most rear, rearaxle, the fifth wheel is placed, moved very long to the back, because of the Fruehauf semi-trailer. Behind the sleeper, a small pin for holding the airhoses and electric wires for the trailer is mounted.
At the very rear, two mudflaps are mounted with the classis Mack Bulldog, and the text, 'The Greatest Name in Trucks' plus a licenceplate and rearlights.
On both sides of the chassis behind the frontwheels, you can find batteryboxes, two airtanks, and a fueltank in both sides. The fueltank is also equipped with stairs for entering the drivers cabin.

Mudflaps Tandems Holder_for_airhose
Tank Batterybox Frontwheel


The engine is made of 3 parts, the block with gearbox, inlet- and outletsystem.
The engine is a straight 6 with working crankshaft and pistons. On the rear is the gearbox, where the rotation from the propeller shaft is directed to the crankshaft. The engineblock is equipped with cooler, manifold (inlet and outlet) turbo, and the special 'tip turbine' intercooler.
The intake system starts at the right side of the hood, in the large airfilter, from here the air is sucked in via two pipes to the engine. One of the pipes goes through the turbo, and from this to the special intercooler, on the top left side of the engine, which are cooled by the air from the other pipe from the airfilter.
The exhaust goes from the turbo, out on the right side of the engine, under the drivers cabin, and out on the right side behind the drivers cabin, and up through the large chromed muffler on the front corner of the sleeper.
Other details to be mentioned, diesel-pump, starter, generator, oil-filters, steering wheel axle, and a lot more.
Access to the engine is possible by removing the bullbar, and tilt the hood, which are supported by a wire, when it is fully open.
Since the engine is not to be seen in the movie, I have found the necessary data and pictures on the internet from truck scrappers.

Hood_open Airfilter Exhaust
Bullbar Engine_left Engine_right

Drivers cabin - outside

On the front of the frame, the bumper is mounted, seperated in two pieces, an upper and a lower. On these the bullbar is monted, in a way so it can be removed to tilt the hood.
The bumber also carries the 4 licenceplates, different plates to different states where the truck is approved in.

The hood includes, besides covering the engine, also the two front mudguards, front lights, and side blinkers. On the top front, a small duck is mounted in the film.
On front and side, signs with 'MACK' and the type 'RS700L' is placed.

The drivers cabin is, compared to European standard, very narrow, not much wider than a normal car. In both sides there is of course a door, with handles, and mirrors with long CB antennas. Behind each door a chromed bar is mounted to support the driver when he enters the cabin.
On the doors you will also find stickers with company name. On the roof is mounted 5 lights, horns and large spoiler.

Right-side Left-door Mirror
Roof Overview Licenceplates

Drivers cabin - inside

Inside the drivers cabin, I have also tried to built as many details as possible.
The seats are black, with vertical stripes, imitating the original leather seats.
The dashboard is brown, like the wood in the original. To the right of the driver, three buttons are placed (a red, yellow and blue) which are the breaks.
On the gear lever, a small button for the range gear is mounted. Above the windscreen, you will find two sun-visors, and the CB radio in the middle.
Its a little hard to see on the pictures, but right above the window at the drivers side, a small wire for the compressor horn can be seen.
Inside light are in the back of the roof.
Besides from all this, some stuff are placed in the windscreen, the drivers log-book, (with a truckpicture), and a sign with the text 'Yes - on prop 14', referring to a political bill, number 14.

Things_in_the_windscreen' Radio Dashboard
Wire_for_horn Door


Behind the drivers cabin, the large sleeper is mounted, it is seperately monted, not like European trucks, where it is integrated in the drivers cabin.
This cabin is in the original truck, 60 inch long, which makes good room for the driver. This cabin is equipped with a large bed, closets, different stuf like stereo, different personal stuf for the driver, fire extinguisher, a number of different lights, and a closet with coat hangers. It took a lot of time to go through the movie to find all these details. I also found to funny texts inside the cabin.

'My Take Home Pay, Wont Take me Home' and 'Truck Drivers are Great Lovers'.

Outside the sleeper is equipped with emergency doors, and small closets under the bed.
On the side of the sleeper, signs for approvals for different states, and companyname for the sleeper is placed.
On the back of the sleeper, 3 workinglights are mounted, and some bars for the driver when he detach the trailer.

Right-side Left-side Text_seen_from_left
Inside_seen_from_left Inside_seen_from_right Text_seen_from_left Company


Final data for the tractor.



59.0 cm


19.2 cm


33.0 cm


43 cm (front axle to center of tandems)

Building time

App. 100 hours

Here are a few extra images of the tractor from different angles.

Finished Finished Finishedg
Finished Finished Finished



The Trailer is a standard 2 axle Fruehauf tanker, with a capacity of 10.000 gallons. Built with 2 axles at the very rear end.
The most difficult part to built of this tanker, is definately to get the right shape of the tank, but more about that later.


The trailer has a small frame underneath the tank, it is not for supporting the whole trailer, since the tank is self-carrying, but instead to be able to mount axles, support legs, spare wheels, etc. on the trailer.

The chassis is built with two longitudinal frames, which has a small bend over the fifth wheel, to fit the height of the tractor.
In the front of the frame, the pin for the fifth wheel is mounted, this part is reinforced, since around half of the weight of the trailer is concentrated in this point. Right behind the bend in the chassis, the support legs are mounted, they are functional by turning a small handle, on the right side. They can be lovered, and raise the trailer, so the tractor can drive away.
Behind the support legs, you will find the spare wheel.
And behind that, in the rear end of the trailer, the two axles are placed, with double tyres. The axles are built with brakes, dampers, and suspension to look like the original. At the very back, the rear bumber is found, including mud flaps, lights, warningstripes, etc.
Pin Support_legs Spare_wheel
Rear_axle Rear_axles Rear


The tank itself, was the hardest part to built on the trailer. It is important to get the right shape, to make it look natural and similar to the original. I used some screenshots from the movie, to find the correct shape and to make a profile of the tank, which I could scale to 1:13 and transfer it into a profile in LEGO studs.
I considered different possibilities for creating the shape in LEGO, my first thought was to make a frame, and place plates around the whole tank, with the studs out. Another solution is to built horisontal, and use a lot of hinges to make the round shape. The last possibility I could come up with, was to built it in normal bricks. I found it the best solution, since it gives a good LEGO look I think, specially in this large scale.
I have used a lot of 'jumpers' i.e. 1x2 tile with a center stud, thereby it is possible to built with half a stud of resolution, which gives smaller steps, and better look. I have used around 3400 of these jumpers for the trailer!

The tank is also equipped with a lot of accessories:
On front, top, the attachment for airhoses and electric to the tractor is mounted. On the side of the tank, 6 marking lights can be seen.
In both sides, in the rear end, a long tube is placed, which can contain hoses for unloading the trailer.
On the right side there is a ladder to make it possible to crawl up the trailer, to the loading cover on the top.
At the very rear end, bottom, an unloading tube, and a tap for opening this is placed, and becides that, some lights, licenceplates, different signs for the tank and trailer properties.
Some of those signs can also be seen on the side of the trailer, to warn about the volatile chemicals inside the trailer.
Couplings Cover Tube_and_ladder Warning_signs
Tap_and_tube Profil Licenceplates Rear Profile


All the stickers used for this truck is made by a good friend of mine Flemming Pedersen, which can make such kind of printing. I have drawed all the signs myself, and then he have printed them.
Unfortunately I could not see in the movie, what the small lettering on the licenceplates said, therefore I contacted JBot Decals, who have made a full set of decals for the truck in different scales. He have made a lot of special stickers for different models, including this trucks, but because I had to go to en exhibition I could not wait for the stickers to arive from Canada, I asked if he could help me with the lettering on the licenc plates, and he was very nice to give those to me.
The quality of his work is very good, so I can highly recommend to contact him, if You need some stickers for a model.


The final data for the LEGO model.



129 cm


19.2 cm


33 cm

Building time

App. 125 hours


October 2005 - April 2006


A small conclusion to this special project; It has been a different experience to built this truck, maybe because the truck is so special to me, it has a large history.
The amount of work to find the information of the truck, watching the movie many many times has been funny, and different compared to my other models, where I could just go and take a photo more, if I needed a detail.

I am very satisfied with the model, I think I have succeded in giving the model a little of the very special apperence and history this truck has in this movie.
I hope you have enjoyed reading my description of the model. If you find some parts which I should have misunderstod og forgotten on the model, you are very welcome to contact me.

I have a lot of pictures of the model, below I have put a few of them. If you like to see more of the model or the original truck, dont hesitate to contact me.

Rubber_Duck Rubber_Duck Rubber_Duck Rubber_Duck
Rubber_Duck Rubber_Duck Rubber_Duck Rubber_Duck


Since I have used a lot of internet sites to find information for this model, I think I will mention some of all those great sites which fans around the world has made to honor this truck and movie.

CONVOY's Rubber Duck Mack Truck Great site with a lof of info of the Mack truck.
CONVOY 1978 Fan-site Fansite with info, posters, models and a lot more.
Rubber-Duck-Trucking A copy is about to be built of the truck.
CONVOY The Movie Great site with information of the movie.

Highresolution pictures

After request I have placed some highresolution pictures of the model. App. 500kb each.

Rubber_Duck Rubber_Duck Rubber_Duck Rubber_Duck
Rubber_Duck Rubber_Duck Rubber_Duck Rubber_Duck