Radio-controlled cars? Des voitures radiocommandées ?

During last month’s Rally Sweden, our colleague Julian remarked that the WRC cars have at least eight antennae on their roof. We tried to find out more…

With all these aerials, the cars resemble radio-controlled models in a toyshop. But what purpose do these eight (at least) antennae serve. Xavier from Ino2 Systems explains...

We begin the guided tour with the patch attached to the front-left: “This antenna is for live video. It is connected to a unit beneath the driver’s seat which records footage from the on-board cameras. These images are transmitted to a helicopter which forwards them to a radio relay airplane, which sends them to Rally TV headquarters. It’s quite complex because the helicopter needs to be at a precise distance from the rally car.”

The white patch on the other side is the GPS tracker antenna provided by SIT. It enables the car’s location to be monitored for safety reasons and functions in association with the bigger aerial that has a power output of approximately 1 Watt. The signal is sent to a radio relay airplane which flies over the rally route at an altitude of around six or seven thousand feet. It takes the signal 250 milliseconds to reach the plane. The rearmost antenna on the car functions in GSM and GPS modes to provide a back-up tracking facility should radio signal be lost.

A GSM aerial for the crew’s cell phones is located at the roof’s centre. Most of the factory cars also have an Iridium satellite phone aerial, and some even have an antenna for data logging purposes (vehicle location, speed, etc.).

Last but not least, the antenna at the rear is for the teams’ own communications. The signal passes via the radio relay airplane and each team uses a specific frequency. “The positioning of the antennae is very important because the roof, like the rest of the car body, is a ‘ground mass’ (electrically conductive surface). To prevent interference and optimise performance, you need to comply with the ‘inverse square law’. There used to be lots of interference because the aerials were too strong, but technology has moved on and today’s transmission quality is far better using less power.”

Au dernier Rallye de Suède, notre confrère Julian nous a fait remarquer que pas moins de huit antennes étaient fixées sur le toit des WRC. Alors on a voulu en savoir un peu plus.

Ainsi équipées, on dirait des modèles radiocommandés vendus dans les magasins de jouets. Le toit des WRC engagées en Championnat du monde des Rallyes FIA est bardé d’au moins huit antennes. A quoi servent-elles ? Xavier (Ino2 Systems) nous a tout expliqué.

Commençons par le patch noir fixé à l’avant gauche. « Cette antenne sert aux retransmissions vidéo en live. Elle est reliée à un boîtier situé sous le siège du pilote qui enregistre les images des caméras embarquées. Elles sont envoyées vers un hélicoptère qui les transmet ensuite à un avion-relais lequel les envoie à la régie. C’est assez complexe car il faut que l’hélico se trouve à une distance bien définie de la voiture. »

Le patch blanc situé de l’autre côté est une antenne GPS fournie par la société SIT. Elle sert au tracking des voitures et donc à la sécurité. Toutes les voitures en sont équipées. Ce patch fonctionne avec la plus grande antenne qui est une antenne-radio émettrice d’une puissance d’environ 1 Watt. Elle envoie le signal à un avion-relais qui survole la zone du rallye à une altitude de 6000 à 7000 pieds. Il faut 250 millisecondes pour que le signal parvienne à cet avion-relais ! L’antenne qui se trouve plus en arrière du toit fonctionne en mode GSM et GPS. C’est une doublure du système tracking décrit précédemment en cas de perte du signal radio.

L’antenne fixée au milieu du toit est une antenne GSM pour le téléphone du pilote et du copilote. La plupart des voitures d’usine sont aussi équipées d’une antenne Iridium (téléphone satellite). Certaines voitures disposent également d’une antenne réservée aux acquisitions de données. Ce n’est pas de la télémétrie comme en circuit, mais elle permet de transmettre des données comme la situation précise du véhicule, sa vitesse…

Enfin, l’antenne située à l’arrière sert aux transmissions radio internes à chaque équipe. Les signaux d’émission/réception passent par l’avion-relais et chaque team dispose d’une fréquence qui lui est propre. « Le positionnement des antennes est très important car le toit, et l’ensemble de la carrosserie, servent de plan de masse. Pour un fonctionnement optimum et éviter les interférences, on doit respecter la règle dite du « carré de l’antenne », c’est-à-dire un carré dessiné autour de l’antenne si on la mettait à l’horizontal. Jadis, il y avait souvent des interférences car les antennes étaient trop puissantes. La technologie a évolué et les transmissions sont aujourd’hui bien meilleures à faible puissance.»

RED HOT CHILI CUSTOMS F650

Who knew that a BMW F650 could be stripped-back and rebuilt into something quite so retro? We were certainly caught off guard when this bike came in. Another Dommie, we presumed – from the thumbnail images anyway – then we clicked. So, our ‘year of the Tracker’ continues with a new donor platform, put together by Red Hot Chili Customs in Poland.

Red Hot Chili Customs are based in Szczecin, on the Polish-German border, just 140km from Berlin. “We’re building and trading oldschool bikes. It’s our love and work in one. It’s really cool that we can do what we love.” Amen to that.

It’s not too surprising that we thought the bike was a Dominator (at small scale) as the build was inspired by the Kiddo Motors Dommi – a bike that had plenty of coverage and well-earned acclaim. Like the Honda, BMW’s bike is a 650cc single in a double cradle spine frame with monoshock at the rear. The main difference is watercooling, which usually means more rpm and more punch. The models were also around at similar times – this donor is from 1994; an F650ST.

The customer for the build was Maciej Zatonski who rode the bike all through Asia and we’re told he was lucky to get it home in one piece. He wanted to rebuild the bike after 76,000 hard kilometers, but nicer, and “a little more handy“.

“We start work as always, reassembling all the unnecessary stuff and leaving only the rolling chassis. The next step was to find the right fuel tank which should work with a scrambler-look and fit onto the angular frame.” The Honda FT500 had the perfect shaped tank, which just needed a new petcock and new mounting points welded to the frame.

The front light is the Trial Tech Eclipse and the silencer is Leo Vince made for an XR650 while the front header pipes are stock which were polished to reveal the bare metal. The rest is all custom build by the RCHC crew. As with all proper pro builds the bike was assembled and test-ridden before being stripped, sand-blasted, then powder-coated or painted.

We always ask if the builders are happy with their handiwork. “Oh yes! The bike is lightweight, powerful, mothafucka!! We’ve love it, and Maciej also!” I think that’s pretty unequivocal. We like it too. We’d like to see more F650s get this treatment, and it’s good to see a knew donor appearing in the scrambler/tracker stable.Now we’ve lot of work with other classics, so stay tuned! To the next build!

See more from Redu and the crew at Red Hot Chili Customs on Facebook, their Website, and here on The Bike Shed.

FOTO-GUTEK

Rocket Supreme motorcycles: We have lift-off, with a twist

Picture your dream custom motorcycle – anything, be it a scrambler, a café racer or a thoroughbred sports bike. Got it? Well then let Rocket Supreme make it a reality…

At Rocket Supreme there are no rules. The folks at the Barcelona-based shop are happy to work with whatever you’re willing to bring to the table. And even if you’ve got nothing in mind, its own creations, the Big Joe I and Little Joe II – so named after some of the first and most innovative space vehicles to blast off from Cape Canaveral – provide the perfect starting block to build on.

Bespoke motorcycles, handmade from carbonfibre

Each motorcycle is bespoke, handmade from carbonfibre by a crack team of experienced and award-winning design and creation specialists, between them boasting over 20 years of experience. You can be as involved in the build process as you please. Fancy checking in on your creation and giving it a test-drive? Absolutely. Prefer to keep in touch via telephone or email? Not a problem.

A passion for quality craftsmanship

Rocket Supreme is offering some of its bikes in the Classic Driver Market. The team is composed of real riders, with real passion for quality craftsmanship. 

Photos: Rocket Supreme

Rocket Supreme bikes can be found for sale in the Classic Driver Market.

HOW TO BUILD A CAFE RACER

By Charlie Trelogan | On Cargo Collective

I’m a car designer by trade: I spend my time working out how to make machinery look as good as it can. Designers are creative people by nature, so we crave the opportunity to be as free as possible in our work. We also have many parameters, tests and boundaries to refer to, to make sure we deliver the best possible ‘product.’

These guidelines are just that—guidelines. Designing a café racer is as much about art as science, and each bike is different in its own way. It reflects the environment, the era and the owner of the bike. Yet there are things we can do to ensure that the result will look solid and professional.

I’ve been influenced by motorbike design for several years, and have built my own café racer. I based it on the same observations that I’ve sketched out here. Hopefully they’ll inspire some fellow builders to invest time into the aesthetics of their project.

To illustrate my points, I’m using the Bike EXIF calendar cover star: Mateusz Stankiewicz’s Honda CX500, built in conjunction with the garage Eastern Spirit.

THE FOUNDATION The foundation contributes most to the structure, direction and general ‘easiness on the eye’ that makes a bike a café racer. First, the simple stuff. Café racers are defined by the flat line that runs front to back, giving an uncompromising look and lending strength and speed to the design. It’s a good idea, though not vital, that this line remains uninterrupted. (The perfect example of this rule being broken well is the Wrenchmonkees’ Laverda 750.)

This line is the first one your brain will ‘see’ and will guide your eyes along the length of the bike. If there are kinks and breaks then it eliminates continuity and, like bumps in the road, makes the experience uncomfortable. This powerful base sits above two fairly evenly sized wheels.

THE ‘CUT-OFF POINTS’ These lines are the wheel centerlines. Anything going beyond these lines will serve to make the bike seem ‘odd.’ Too much over the rear wheel will make the bike seem rear-heavy and poorly planned. It’s quite common for bikes to do this, however, and it’s not a big deal if crossed over by a small amount—as in our example.

If you do go too far over, then minimize the depth of the seat or cowl. There’s nothing worse than a big cowl hanging over the back end of the bike. The front is less of a problem but front fenders cut on this line look best.

HEIGHT LIMIT Just as important as the cut-off points. The height limit gives a planned look to the design. Defined as the highest point on the fuel tank, anything protruding much above this point will take away from a café racer’s sleek and streamlined looks. It will also serve to make your bike look more like a tracker and less like a café bike. Keep it low and keep it clean. Combined with the cut-off points, this imaginary box should contain all the major elements of your design.

THE ‘BONE LINE’ Hugely important in car design, it is very important here as well. The bone line serves to describe where the widest point of your bodywork is. This is where your reflections on your seat, tank and lamp will fall. Think of the ‘bone’ as the 3D brother to the more 2D foundation line. They work together as a team. Here the center of the lamp is right on the bone line: A great decision that ties the whole upper together.

If you get anything right it should be this. It immediately makes the bike look like it really belongs together and is not just a jumble of parts. Next time you see a bike (or indeed a car) you like, take some time to see if it has this central ‘bone’ and where it sits. This Honda is a perfect example and, though it’s not the first thing you might realize you see, it’s why this is not just a good bike, but a great one.

THE VISUAL WEIGHT This is where the main ‘mass’ of the bike is, and it can be split into two parts. Firstly, the main mass is the engine—including the cylinder/crank/gearbox, or anything towards the front of the subframe. This is your tank parameter. A tank longer than this will look overly big and heavy, and a smaller tank will look like the bike has outgrown it—almost bobber-like.

Secondly, and just as importantly, is the axis of the visual weight, seen here in the middle. This is usually defined by the middle of the engine, or more accurately, the middle of the cylinder/piston. This will define the ideal shape of the tank. The peak of the tank should fall right on or very close to the axis. It is amazing how much more robust and ‘sporting’ a bike looks when this is incorporated into the design.

It applies equally for bikes such as Hondas, Kawasakis and Yamahas that have inclined engine blocks. The axis still falls through the middle of the cylinder at that angle. The result is that these Japanese bikes look better with tanks that peak towards the very front of the bike and taper off towards the rider.

THE SWOOP Ideally you want the seat and the tank to look like they belong together. We can do this by making sure the curve of the tank flows into the curve of the cowl. This will make it look almost like the tank and the seat were once a single piece of metal, and someone scooped out a place for a rider to sit. It makes it look intentional and tight.

PRIMARY ANGLES Often overlooked, the differing angles on a frame with those of the forks, shocks and other parts can make a spaghetti of lines which could ruin all your hard work. Be considerate of them when adding new parts. Here this bike has a brand new subframe to clean up the wobbly CX500 original. The builder has very cleverly matched the angle of the front fork, making it look cohesive. Angles are something we take great care of when designing cars too.

SECONDARY ANGLES Even in small areas, the builders have tried to make parallels of two or more angles on different parts. This is some subliminal stuff right here. You might not notice it—but you can bet that your brain does on a certain level.

FORK DISTANCE Keep the front wheel as ‘tucked in’ as possible. It gives a bike a ‘pouncing’ and aggressive stance. I know a fork swap might seem like a good idea, but don’t make it look like a chopper, OK?

I have seen bikes that match this guide to the letter that look great. And I have seen bikes that disregard them totally, and still look amazing. Following these guidelines will give you a base on which to work and help understand why a bike looks like it does.

Once aware of these ground rules, it’s up to you how you choose to stick to them—or break them.

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