Fijon FJ9 Project

Page 1: Assembly

The FJ9 comes in a rather non-descript box with some very strange wording. It refers to this as a "counter-peptide" drift car by which I assume they mean "counter-steer". Counter-steer isn't a very good term either because it has naught to do with counter steering (which is a real thing). In the context of an RC drift car it just means that the rear axle is geared higher than the front. The parts inside are divided into bags as shown.

Here you can see some of the glorious parts. On the left are an unreasonable number of machined aluminum parts, and on the right are a ridiculous number of laser cut carbon parts. Everything is carefully bagged. Zoom in and behold the glory.

Here are some more detail photos of the hardware and mechanical parts. Pretty much everything is machined aluminum or steel. Hardware is divided into seven numbered bags.

The rear shocks are fairly traditional but use a lot of parts as you can see. Shock body, caps, rod end, and spring perches are all aluminum.

The front shocks are very unusual for RC but very normal for cars. These are real MacPherson struts which means that the shock serves double duty as both a damper and a steering knuckle. The rod turns within the barrel when the car steers. The upper end has no lug but instead bolts directly to the chassis with a round plate (like the real thing)

Now we can start the rest of the front suspension. The steering system uses aluminum dual bellcranks with ball bearings and a carbon cross member. The lower suspension arms are also machined aluminum with spherical balls for kingpin joints. The balls on the front side sit on carbon plates and are for the connection of drag links.

The whole gearbox is located above the front axle and is driven by belts. We start with what is effectively a flywheel and shaft attached to the forward bulkhead which then bolts to the front carbon chassis plate. This plate incorporates the front bumper. The bulkhead supports the front end of the lower suspension arms, and the rear ends are supported by pillow blocks. The rear side of the flywheel shaft has the pinion gear for the front ring gear.

Oddly enough, the only plastic parts on the model are the gears. There is no differential so this ring gear just drives a locked spool supported by ball bearings. The support blocks span the front axle and support the rear half of the front bulkhead.

These pictures show the temporary motor I installed while waiting to decide on a power system. There is no motor pinion, instead the motor shaft support a small pulley. This pulley drives the large pulley which goes right to the front wheels. The second smaller belt will end up driving the rear axle.

Behind the motor we see another belt which transfers power back down to the car centerline for the prop shaft which will go to the rear wheels. It might appear to have two identical pulleys, but they actually have a 1.3:1 ratio and therefore send 30% overdrive to the rear axle. Those belts are tight and put a lot of side load on that axle so it is important the axle be supported at both ends. On the right you can see the front support as well as the drag links attached to the lower suspension arms. You can also see a small bearing which acts as a belt tensioner.

There's probably no reason this front fascia support needs to be aluminum, but I'm OK with it. It will indirectly be supporting the top ends of the front shocks. Remember, there are no upper suspension arms with a Macpherson Strut suspension, but the steering links and knuckles have been added.

I chose a 10.5T Hobbywing brushless motor for this car, but the available space was so tight than I had to mill away a pocket in the rear closure to get it to fit. Once installed, you can hardly tell I changed anything. The belt drive system has quite a bit of drag so it takes some non-trivial throttle to get things spinning even without wheels attached.

The rear carbon chassis plate is huge. It's the single largest bit of RC carbon fiber plate I've ever seen. It is so choice. The guards you see toward the back are the supports for the transverse mounted battery. The battery is a standard stick pack size, so that shows you how wide the plate is. The aluminum bit is a lower suspension arm support.

The rear lower arms look much like the front with the spherical ball joints and carbon drag link plates. There is no toe angle on the hinge line.

The rear spool is enclosed in a box which incorporates a slight incline on the drive cup. Like the front, this is a locked spool with no differential.

Here you can see the incline on the rear prop shaft which allows it to pass over the battery tray. Two vertical carbon plates are then installed to form a chassis center channel. You can also see the carbon shock and body supports in the rear.

Now the rear upper suspension arms have been installed. The length of these can be adjusted to vary camber angle. The rear drag links have also been installed.

Now that's a lot of carbon. Even the wheel arches are carbon fiber. This is also the point at which the rear wheel hubs and shocks are installed as shown on the right.

Finally the front and rear halves of the chassis can be connected together. To complete the chassis a pair of seats and dash board are installed. These are transparent polycarbonate parts which I painted black. The kit did not come with wheels or tires so I used some that I had from another car as a start.

This part is the only one that caused me a problem during assembly. This is a clamping 12mm drive hex, but the clamping face was so thin that it deformed instead of clamping. I had to replace it.

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