My final 2010 Truck Trial vehicle, built in less than single week after the previous vehicle failed. Features full pendular suspension, 4×4 drive, lights and opening doors, bonnet and rear board.

Datasheet:

Completion date: 03/09/2010
Power: electric (Power Functions)
Dimensions: length 48 studs / width 26 studs / height 27 studs
Weight: 1.985 kg
Suspension: pendular, stabilized with shock absorbers
Propulsion: 1 x PF XL motor geared down 5:1
Top speed: uknown
Motors: 1 x PF XL, 1 x PF Medium

When I decided to abandon my Fiat SPA35 model, it was just a week before the Truck Trial race and my first decision was to pass on driving this time and to only take care of filming. Shortly after, I changed my mind and decided to try some simple 4×4 vehicle, just to drive something in the race. The vehicle was intended to combine the advantages of my two previous Truck Trial vehicles – Hummer H1 and Jeep Wrangler Rubicon, while also learning from Fiat’s failure. I wanted to try to model another famous 4×4 vehicle, so the classic Land Rover series 2 (dating all the way back to 1958) was pretty much an obvious choice.

While the complete model appears much like a Hummer/Wrangled hybrid on the outside, it was internally much closer to the Fiat model. The chassis was built completely with studless parts and used large Technic turntables to hold suspension modules in place – both solutions tested in the Fiat for the first time. The Land Rover shared engine location, gear ratio and wheels with the Wrangler and a studfull body with the Hummer. In fact, the Rover used studfull body around a studless chassis, whereas Wrangler used studless body around a studfull chassis.

The suspension has undergone some major changes in comparison to the version used in Fiat. The front axle was reverted to the version used in the Wrangler, and then a single turntable was attached behind it and the steering system was additionally reinforced. Both drive and steering were transferred through the turntable – steering by a solid driveshaft and steering by am empty differential sitting on it. The rear axle was built from a scratch between two turntables. There was no gearbox, and – just like in the Wrangler – the drive motor was located above the front axle, right under the bonnet. The racing rules we use state that every model has to be equipped with a piston engine of accurate configuration and placement, unless the actual drive motor is located where the original engine is. Thus, locating the motor under the bonnet meant that no piston engine was needed in the model, which saved space, weight and drive motor’s power. The steering was controlled by a single PF Medium motor geared down 15:1 and located low in the chassis, in front of the rear axle. The entire underside of the chassis was covered with studless parts, in order to create a single smooth surface that was unlikely to get  stuck on an obstacle, and in order to lower the centre of gravity as well.

Knowing that my Wrangler model had abundance of torque, I wanted the Rover to be much heavier.  Our racing rules take power-to-weight ratio of each individual model into account, therefore more weight at the same power means more points. Thus, I wanted the body to be massive, but at the same time it was my goal to keep the model’s centre of gravity low, despite its significant ground clearance (up to 7 studs under cabin’s floor). Therefore especially the lower portion of the body was built so densely that model came out almost undamaged from some crash tests I conducted later.

The body was equipped with a pair of opening doors, an opening bonnet with a spare wheel fixed on top of it (a common sight in early Land Rover versions), and opening rear board with the IR receiver attached to it. Most of the Land Rovers can be accessed from the back by a single door, and a board is a rarity. I chose the board over door because this way the IR receiver was more exposed, and could be pulled out from the cabin’s inside to some extend if needed. Moreover, the rear part of the cabin has been adapted to house a camera. Due to weak mounting points, this solution worked well only on flat, level surfaces, as proven during the race.

It should be noted that the model’s body was inaccurate: the front radiator grille should be put further back under the bonnet. I couldn’t model it because of the frame that braces the suspension module of the front axle. Moreover, inspired by the Inception movie featuring a tracked Hummer H1, I have created a simple set of four tracks for the Land Rover. The tracks and wheels could be easily swapped in the chassis, and while I did not intend to use the tracks outdoors (our racing rules don’t allow tracked vehicles of any kind), I have used these to drive around my apartment. The general performance was apparently inferior with tracks on, and in particular the traction was much worse than it was with wheels.

The completed model weighed a whopping 2.1 kg until I removed ballasted bricks that were mounted under the bonnet in order to shift the centre of gravity forward. It reduced model’s weight to just below 2 kg, and I decided to leave it like that because there was no time left for changes. The model performed well at this weight, it experienced no mechanical failures and displayed superb traction, but it was obvious that it will be struggling against its own weight.

Land Rover was warmly welcomed by other contestants because of its look and its very short building time. It performed well in the race, no mechanical failures occurred, but its weight turned out to be a real problem. The model ran out of power to climb on several occasions, and toppled over once. It ended up at the last place in the race, much to my disappointment. Yet still, other drivers and viewers were greatly impressed by its look, which led me to believe that it would be a waste to take it apart, and that the model should enter our last 2010 race on October, with open body design that should significantly reduce its weight.

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Datasheet:

Completion date: 18/04/2010
Power: electric (Power Functions)
Dimensions: length 47 studs / width 24 studs / height 23 studs
Weight: 1.224 kg
Suspension: pendular, stabilized with 2 shock absorbers per axle
Motors: 1 x PF Medium, 1 x PF XL

After the disappointing failure of my Tatra T815 truck, I was left with less than two weeks time until the next race. Re-using Tatra was out of the question, so my only option was to build some simple and small 4×4 vehicle. Since our current rules allow this type of vehicle into competition, I decided to model the iconic Jeep Wrangler in the acclaimed Rubicon version. It was built in roughly 4 days.

The basic rule of this construction was to keep everything as simple as possible and to reduce the weight to minimum. This is why the body was built with the new Technic panels, which provide the best combination of stiffness and lightness. Both front and rear axle are built entirely with liftarms, but the frame that connects them is built with Technic bricks. The reason to use bricks was that I wanted to build a roofless version of the Jeep in order to obtain low center of gravity, and since the sides of the cabin are made of single panels, the whole model had to be kept together by the cabin’s floor. Therefore there are bricks in the floor, that provide excellent stiffness and robustness while keeping the floor thin.

The chassis, which weights just 0.75 kg, consists basically of the studfull frame connected with studless axles. Since there is very little space in front of the front axle, both drive and steering had to be transferred to the front axle from behind. This was achieved by placing a 16-teeth gear with a clutch on the driveshaft – this gear works as an idler gear between two other gears, thus transferring the steering independently to the drive. Front axle is compact but massive, strong enough to handle much heavier vehicle, and it’s bottom is entirely covered with liftarms to prevent it from getting stuck on an obstacle. It should be noted that both axles use knob wheels instead of differentials, and both are portal axles with an integrated 3:1 gear reduction. Each axle is stabilized by a pair of short shock absorbers located between the axle and the frame for maximum structural integrity. In order to minimize the effect of central driveshaft’s torque tilting the body, which occurs when only pendular axles are used, the axles are stabilized with the hardest shock absorbers available. The rear axle is built around the 7×5 liftarm frame and is not covered from below.

The model is driven by a single PF XL motor with a total 5:1 gear reduction, and the motor’s location is strictly related to our current rules. Our rules state that every model has to be equipped with a piston engine whose set-up and location are consistent with the original engine. This rule, however, can be omitted if the drive motor is located exactly where the original engine is. This is Jeep’s case – the PF XL motor occupies exactly the same place that is taken by the original engine in a real Jeep, hence there is no need for the piston engine and the model can be simpler and lighter. You can see the top ends of the front axle’s shock absorbers next to the motor. It should be noted that the PF XL motor actually touches the front axle, but because it’s located in the center of the chassis and because it has a round shape, the axle can still oscillate under it. Such a trick was necessary to fit the XL motor under the bonnet.

The steering is controlled by a PF Medium motor with a 9:1 gear reduction. The motor is located between the seats in the cabin, and the steering wheel is connected to it. The cabin has a safety cage built on top of it, which is strong enough to survive a turnover without any damage. Finally, there is the 8878 rechargeable battery box and the IR receiver located over the rear axle, as a counterweight against the PF XL over the front axle.

One special feature of the bodywork is a droppable modules design. The obstacles used in our races are often larger than the ones the real vehicles are designed for, so the usual practice to handle this difference is to increase the model’s ground clearance. I wanted to avoid it, however, to keep the Jeep’s center of gravity as low as possible. It meant that some parts of the body are very likely to touch the ground e.g.  when the approach angle proves to be insufficient. Therefore I designed a number of body elements as independent modules that would fall off when stressed, on assumption that it’s better to drop something than let it get the whole vehicle stuck. The list of droppable elements includes front and rear bumper, rear spare wheel and front mudguards. The sides of the cabin are somewhat elastic too. This design is also helpful when the front wheels’ steering lock makes them collide into some parts of the body.

The model turned out to be pretty stable, with a well performing suspension and an excellent amount of torque available. It was my goal to prefer the torque over speed, since I did not want the model to get stalled under any circumstances while its speed didn’t seem crucial. This is second model of a Jeep used in our races, and it’s much different from its predecessor, the Jeep Willys built by Atr. Among other things it is heavier, larger and slower. Observing the two models compete against each other and comparing their performance will be certainly a great experience.

The main disadvantage of this model is its size. The standard scale used for vehicles in our races is 1/13. I was in hurry while building the Jeep, so I picked up the wheels I found most suitable and scaled the whole model accordingly to their size. Eventually it turned out to be in 9/1 scale which is much different from the required one, and will probably result in letting this model race outside the official ranking (in a so-called ‘open class’). Still, building and testing this model was a valuable experience, and driving it in a race will be so too. It was also acclaimed by other builders and race contestants for its look, its authenticity and its performance. If it turns out to be successful in the race (meaning that it suffers no fatal malfunction and doesn’t end up last), I will prepare and publish a complete step-by-step instruction for it, as well as schemes of front and rear axle along with their individual instructions.

Update: since the Jeep performed well at the race, the instructions are under the photos.

Photos:

Full instruction with parts list:

Photo-instruction for the whole model:

Videos:

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Model of a classic hotrod. Features full independent suspension, rear axle drive, functional steering wheel, V8 piston engine, openable doors and custom stickers.

Datasheet:

Completion date: 26/07/2009
Power: electric (Power Functions)
Dimensions:  length 51 studs / width 30 studs / height 22 studs
Weight: 1.78 kg
Suspension:  full independent
Motors: 2 x PF Medium, 1 x PF XL

I have previously created a numer of variations on the ever-popular hotrod theme, until recently, having bought the Technic Racing wheels with the substantial help from donors, I have decided to finally build a classic hotrod. It was inspired by a number of hotrods built for the drag racing, and especially by the Wild Thing based on a Chevrolet Independence.

My important point of reference was my own model built eight months earlier, called the Flamboyant Hotrod. I wanted to explore the direction it set, that is a relatively small, short vehicle with curved sides, but this time I wanted it to look much more realistic. I was so pleased with the final effect that this is actually my first hotrod without the word “hotrod” as the part of its name – I felt that the type of the car is finally clearly apparent.

The front part of the vehicle was kept as simple as possible, and I think it served it well. The V8 piston engine was fitted with a large front fan and two side turbines – all of them moving together with the pistons. It should be, however, noted that I cared little for the realism of the engine design, so it has some features of a real engine, but is mostly made up. Since the engine was complex, and the drive motor was located far from it, I decided to do something very inappropriate and use an extra motor only to drive the engine. It is a blessing in disguise that both motors are coupled and hence both have their speeds controlled remotely, which looks particularly spectacular for the engine.

The cabin houses a drive motor, two IR receivers and the 8878 rechargeable battery, along with a simple interior. Both doors are openable, and the receivers are located at the rear windshield, under the roof, which causes some difficulties with the model’s remote control. Two notes about the cabin’s look: firstly, the rear part of it may look odd, because I intended it to appear as if the rear mudguards have been removed along with the adjacent body panels. It was actually the only way to fit the rear suspension and big rear wheels in. Secondly, the cabin is entirely black and only decorated by stickers. That is because I wanted the body to look sort of shabby, and the stickers seemed the only way to obtain that.

The suspension system is based closely on the solutions from the 8448 set, with rear axle driven through a differential of a new type, with a bracing I have developed some time before. The rear axle was also deliberately made wider. The steering system is quite typical, with a safety clutch and a functional steering wheel. The transmission system is trivial, and consists of a single PF XL motor, a single gear and a single differential. Since the motor already required much space inside the cabin, and I had the speed-control enabled handset at my disposal anyway, I didn’t feel it necessary to make it any more complex. Finally, the 8878 battery is located in the trunk, and it’s small dimensions are very useful here. There is a small flap on the side of the trunk that allows to turn the battery on or off.

The model, which took me only one week to build, enjoyed a good reception. Despite the technical simplicity, it was acclaimed for its classic look and for its impressive piston engine.

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Model of a classic Morgan 4-4. Features full suspension, remote drive & steering, functional steering wheel, lights, manually opened doors and manually adjusted seats.

Datasheet:

Completion date: 03/01/2009
Power: electric (Power Functions)
Dimensions:  length 48 studs / width 17 studs / height 16 studs
Weight:  1.39 kg
Suspension:  front – pendular without shock absorbers/ rear –  independent
Motors: 1 x PF Medium, 1 x PF XL

From time to time I am accused of ignoring aesthetics for the sake of functionality. These accusations are still present, even though the influence of LUGPol users made me pay much more attention to aesthetics than I used to do earlier. With this model, I wanted to answer this kind of accusations, and to prove that I can build a good-looking medium size car model, despite the failure the Cobra model was.

The front part of the car was the biggest challenge. I have developed my mini pendular steered suspension module specifically for this model, and managed to contain it under the narrow, low bonnet. The steering lock was greatly limited by the mudguards. Steering was controlled by a PF Medium motor with a safety clutch, thanks to which it was possible to use driver’s steering wheel instead. The drivetrain was very simple, and consisted of a PF XL motor driving the 3-studs wide differential. There was no rear axle, however, and instead the rear wheels were suspended on dragged longitudinal rocking levers. This solution provided better stability than a pendular suspension could provide (no torque effect), as well as more internal space for the battery box behind rear wheels. The only drawback was the robustness and stiffness of the rear suspension, which were worse than in case of a pendular one. The PF XL motor was located under the seats, and the IR receiver was put between them.

The look of the model was fairly accurate, with a number of minor concessions to the functionality. Namely, the front mudguards were not fully covered, but had holes behind the headlights, to preserve internal space for the front wheels’ movement, the tresholds on the sides of the car were taller than they should be, in order to contain all wires inside the chassis, and there was an opening atop the rear part of the body, which provided access to the battery box switch. Given the size of the model, I consider these concessions acceptable.

The model was well received, partially thanks to the mr Fluffy’s great work on modeling. Some of the people following my work called it a rehabilitation after the Cobra failure. Additionally, it was my first construction published at LUGPol outside the Technic section – I’ve chosen the Model Team section instead.

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Video:

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Media reference:

Klocki

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A simple buggy. Features 2-speed remotely controlled gearbox, live rear axle and lights.

Datasheet:

Completion date: 23/11/2008
Power: electric (Power Functions)
Dimensions:  length 47 studs / width 25 studs / height 25 studs
Weight:  1.08 kg
Suspension:  front: independent with shock absorbers / rear: live axle on shock absorbers
Motors: 2 x PF Medium

A simple sandrail (subcategory of buggies), built basically to test my live axle concept. A live axle is an axle that has no fixed attachment to the frame of the vehicle. Instead, it is connected by a system of links and supported by shock absorbers. Live axle suspensions are usually complex, but offer very good stability and excellent performance, comparable to those of a typical independent suspension. And just like the independent suspension, live axle does not let the vehicle’s weight affect the drivetrain, which means that it performs better in heavy vehicles that the pendular suspension does, because the weight doesn’t generate extra friction on the drivetrain components (except wheels, of course).

In Lego, a very complex live axle systems exist, with probably the most extreme example available here. Therefore my goal was rather to create something as simple as possible. I ended up with an axle suspended on 4 links and a driveshaft only – a solution that turned out to blend simplicity with reliability pretty well. It had two minor drawbacks: it was slightly affected by the driveshaft’s torque, just like the pendular suspensions are, and the driveshaft could be theoretically affected by the vehicle’s weight to some extent while maing a turn or climbing certain obstacles. Despite that, this suspension system worked far better that I could expect.

Another noteable feature was the use of the direction sensitive gearbox I have developed earlier. It was braced by liftarms here, and allowed the vehicle to be driven only forwards. It did work as expected, but the liftarmic frame turned out to be somewhat loose, and did not deliver the kind of performance that traditional bricks could.

The model was built with minimal attention to the aesthetic side, I just wanted it to look realistic, not pretty.  Therefore I’ve used rather unusual palette of colours, and did not intend to film the vehicle. The LUGPol community, however, showed much interest in the suspension concept, and persuaded me into filming it, so I’ve eventually published a video titled Live Axle, to emphasize the fact that it was the suspension concept that was important, not the actual car.

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A classical HotRod. Features full independent suspension, V12 piston engine, lights, openable doors, and 2-speed manual gearbox.

Datasheet:

Completion date: 12/11/2008
Power: electric (Power Functions)
Dimensions:  length 50 studs / width 29 studs / height 20 studs
Weight:  1.68 kg
Suspension:  full independent with shock absorbers
Motors: 2 x PF Medium

I’ve felt unsatisfied in the HotRod area after finishing my Hot Black, and in the area of cars after finishing my disastrous Cobra. That is why, having found a proper inspiration, I decided to build another HotRod, with focus mainly on the aesthetics, but with functionality in mind as well. It resulted in a model that I consider one of my prettiest cars. It was fitted with a full independent suspension based largely on the 8448 set’s components. Steering and drive were both controlled by PF Medium motors, thanks to which I was able to include the entire mechanics inside the car’s chassis. The battery box was located at the back, behind the seats, with the IR receiver between them.

The body of the car used a large number of slopes, curved slopes and tiles. I tried to make it appear a bit ‘chopped’ in the front part of the vehicle. Both front & rear lights were present. The steering wheel was non-functional, as I didn’t want to make the front of the car too complicated. To diversify the look of the rear of the car, a small box built with half-stud-offset technique was added between rear lights.

The model enjoyed a good reception, but didn’t get much attention. I, on the other hand, very much liked its silhouette, which appeared to me free from any technically imposed deformations.

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Most unfortunate result of my fascination in vintage cars. Features full suspension, lights, illuminated engine, electrically opened driver’s door, and a functional steering wheel.

Datasheet:

Completion date: 07/09/2008
Power: electric (Power Functions)
Dimensions:  length 63 studs / width 18 studs / height 15 studs
Weight: 1.95 kg
Suspension:  pendular with shock absorbers
Motors: 2 x PF Medium, 1 x PF XL

Fascination in vintage cars prompted me to build a car inspired by the legendary AC Cobra. Upon assumption that the shape of the car’s body is too complex to be exactly modeled, I decided to completely ignore dimensions of the original car. It resulted in a disaster, as the car turned out to be way too long, not similar to the actual Cobra, and plainly ugly. I published it anyway, only to demonstrate a number of technical solutions.

The narrow front pendular suspension design was a novelty at the time for me. So was the use of the Lego fiber optics to create illuminated engine bay. The car performed not too well, as the suspension lacked stability, because all axles were pendular with only one of them driven. There is nothing I can say to make this construction appear successful. It still shocks me to see that some people actually like the way it looks, whereas I consider it an obvious failure.

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Another HotRod-like car. Features V12 piston engine, remote drive and steering, and remotely folded roof.

Datasheet:

Completion date: 16/06/2008
Power: electric (Power Functions)
Dimensions:  length 51 studs / width 20 studs / height 18 studs
Weight: 1.7 kg
Suspension: none
Motors: 3 x PF Medium

This is somewhat strange construction. It resulted probably from the feeling that my HotRed has been underestimated, so I decided to create a version with the body built from regular bricks and more focus on aesthetics than on the functionality. The functionality has been actually severely crippled, as this car has not only the gearbox, but even the suspension and the functional steering wheel removed – quite a rarity among my cars. Except for drive and steering, the vehicle was fitted with a simple folded roof, controlled by the third motor. It has been ugly in my opinion, and had little relation to the real HotRods. However, the effort I put into building its bonnet resulted in an experience that was very useful at my later models of American trucks.

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]]> http://sariel.pl/2009/01/hot-black/feed/ 5 http://sariel.pl/2009/01/dragster/ http://sariel.pl/2009/01/dragster/#comments Mon, 05 Jan 2009 18:29:25 +0000 Sariel http://sariel.pl/?p=244

Very simple lightweight car, built exclusively for speed tests.

Datasheet:

Completion date: 18/05/2008
Power: electric (Power Functions)
Dimensions:  length 41 studs / width 26 studs / height 16 studs
Weight: 0.94 kg
Suspension: front – independent / rear – dragged axle
Motors: 3 x PF Medium

A very simple construction, built exclusively for speeding. Very softly suspended, it is driven by two PF Medium motors, that don’t use any real drivetrain, but are connected directly to the wheels, and together form the rear axle. To make both motors drive in the same direction, I have connected them two different IR receiver outputs, which resulted in the addition of a second receiver used for steering, as the PF switches were not yet available at the time.

It was built with little concern for aesthetics or robustness. The look was completely different from what you can expect a dragster to look like, and the rear wheels were falling off from the motors from time to time. It was, however, as fast as it could to be controllable inside my apartment, and provided a lot of fun while drifting. I do not consider it to be a limit of speeds possible with the PF system.

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]]> http://sariel.pl/2009/01/dragster/feed/ 10 http://sariel.pl/2008/12/hotred/ http://sariel.pl/2008/12/hotred/#comments Tue, 30 Dec 2008 11:37:16 +0000 Sariel http://sariel.pl/?p=186

Another take on the subjects of HotRods. Features full independent suspension, V14 piston engine, functional steering wheel and a 4-speed manual gearbox.

Datasheet:

Completion date: 01/03/2008
Power: electric (Power Functions)
Dimensions: length 52 studs / width 28 studs / height 19 studs
Weight: 1.34 kg
Suspension: full independent
Motors: 1 x PF XL, 1 x PF Medium,

Probably my first serious attempt to build a good-looking car. While it’s been largely inspired by the 8448 set, the basic concept was to create vehicle that appears like a ‘hotrodized’ Bugatti Type 35. I have been quite happy with the aesthetic side of the model, and hence the first wide use of post-processed photos.

The construction is, I believe, not typical for me. While I usually tend to create large, massive, complex vehicles, here the idea was to use only as many parts as necessary, and to keep in mind how every single part reflects on the look of the whole car. I like to think that it’s been built in a temperate way, and avoided excess of any kind.

The vehicle offers a number of features uncommon for its size. The suspension system, entirely independent, is taken from the 8448 set, with some minor modifications that increased the ground clearance and made the rear axle slightly narrower, simplied and stronger. The drivetrain is somewhat unique, not just because of the presence of a 4-speed gearbox, which has already been used in my earlier front loader model, but mainly because of location of the drive motor. An easy and popular solution involves locating the motor ahead of the gearbox and rear axle. Here, the motor is located right behind the rear axle, the drive is transmitted over it to the gearbox, and then finally to the axle’s differential. Please note that the V14 piston engine in front of the car is driven via the gearbox in a realistic way: that means, it works at the same speed regardless of the gear selected, including the idle gear. I consider it a realistic technical detail, and I’m using such a solution always when a gearbox and a piston egine are involved. The entire drivetrain mechanism is compact and strong, and has spared a great number of space in the chassis. Its diagram can be found among the photos below.

Other features include a functional and adjustable steering wheel, as well as a V14 piston engine. The car was fitted with a V12 version first, but there was still some space left, and I thought that some extend in the engine size is quite characteristic for HotRods. Some V14 engines did, in fact, exist, although they have been only used in a few planes, and none in a car as far as I know. Theoretically it should be perfectly possible to do that, as there are even some examples of aircraft engines used in WW2 tanks.

Photos:

Video:

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Media reference:

The Brothers Brick

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]]> http://sariel.pl/2008/12/hotred/feed/ 7 http://sariel.pl/2008/12/roadrunner-buggy/ http://sariel.pl/2008/12/roadrunner-buggy/#comments Tue, 30 Dec 2008 09:50:37 +0000 Sariel http://sariel.pl/?p=165

Small, simple lightweight buggy. Features full suspension and rear axle drive.

Datasheet:

Completion date: 20/01/2008
Power: electric (Power Functions)
Dimensions: length 37 studs / width 22 studs / height 26 studs
Weight: 0.86 kg
Suspension: front – independent / rear – dragged axle
Motors: 1 x PF Medium, 1 x PF XL

This project was intended to test what speed can be achieved with a PF XL motor, and additionally I was hoping it could drift a bit. There is a differential with 4 bevel gears in the rear axle (a technique developed by LUGPol user Aro_kal), and the gear ratio accelerates motor’s output speed almost twice. The buggy proved to be fast and manoeuvrable, but a bit too slow and to heavy for drifting (probably in part because of the battery box over the rear axle), unless it was given rear wheels without tires and placed on some tiles instead of a regular floor.

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]]> http://sariel.pl/2008/12/roadrunner-buggy/feed/ 6 http://sariel.pl/2008/12/hotrod-4wd/ http://sariel.pl/2008/12/hotrod-4wd/#comments Tue, 23 Dec 2008 16:06:51 +0000 Sariel http://sariel.pl/?p=44

First attempt to build a HotRod and make use of the 8880 set suspension parts.

Datasheet:

Completion date: 22/05/2007
Power: electric (wire-controlled) / pneumatic (fed from internal manual pump)
Dimensions: unknown
Weight: 1.55 kg
Suspension: full independent with shock absorbers
Motors: 1 x RC, 1 x 2838
Pneumatics: 1 circuit with an airtank

My first attempt to redesign the suspension of the 8880 set. I have improved the suspension travel distance, steering lock, and mounted the shock absorbers in such a way, that they could be easily set at a different angle or replaced with absorbers of the same type but different hardness. The car is fitted with 4 wheels drive (quite unusual for HotRods), 2-speed manual gearbox (using a transmission driving ring)  and a V12 piston engine. Very unique feature is a pneumatic brake, using a large manual pump, a valve, an airtank and a small pneumatic cylinder. The pump is mounted under the body, to imitate part of the exhaust system, and the cylinder is hidden inside the openable trunk. Its working principle is very simple – there is an axle behind the rear suspension, connected to the drivetrain, and it has a wedge belt wheel with a tire on it. When the brake is activated, two liftarms are pneumatically pressed to the sides of the tire, causing the motor to stall due to increased resistance, and thus stopping the car in an effective but gentle way. I was afraid of damaging some drivetrain parts while braking, hence the use of a tire as a ‘muffler’ between the brake and the actual drivetrain.

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