F103GT chassis
After 2 long weeks of waiting, the new chassis arrived. It's inspired on the 'old' F103 formula one chassis - with a bunch of options included: doubledeck chassis, active front suspension, ball bearings, height-adjustable gear case. Also, the newly designed rear diff / wheel hubs are really cool. The differential has some new parts, it has (nearly) no slip.
I want to make my 100+ km/h car out of this chassis, but it will take some work. Some optional parts were added from the go: carbon rear shaft (not available for F103GT yet), titanium screws, small size servo, 63T spur and 24T pinion. This is the most radical gear ratio possible with this car - unless you modify the gear box... Hmmmm... Contemplating...
The new rear suspension: made to fit touring car rims. The spur is from my old F102 chassis, the diff pressure plates are from my old F103. Also note the cooling-holes in the motor.
The body on this chassis. It's too wide for the wheels, but other than that, it fits nicely. To build a decent dragster, I should lengthen it a bit.
Chassis-overview: I removed the pressure-plates and damper, and replaced it with a solid rod. Note the position and mounting method of the antenna.
I made an 8 cell pack with 2/3 cells, 1200mAh. I'm not sure if these can deliver the power I need when I need it - but, when charged, they deliver 12V...
My brake fets on the Novak 410 HPC are probably shot - they will need replacing... I also need to find a decent shottky diode. This one started smoking after 30 sec at full throttle. :s
Comparison: My TBO2R car wheighs in at 1580 grammes - ready to race. This chassis, in combination with 8 2/3 cells, is 1053 grammes. This should make a big difference on a fast track.
This should make it move... 9D motor, with 1:2.625 gear ratio... Also, the wheels have a larger diameter than the old F1 tyres. So torque will be low - but top speed huge!
Stuff I need to do:
- Buy & fit telemetry system
- Add aluminium motor mount
- Find a decent shottky diode or change ESCs
- Find and fit decent gripping tyres
- Possibly get a new, lower body
- Possibly a new, longer chassis, an improved upper deck, and a trich to make the front end of the chassis stiffer... Plans are being made - designes are being... Well... Designed.
Cranking up performance
Now, if I want to get a 100+kph car, I will need an accurate reading of its actual speed. So I bought the Venom speed meter, which is sort of a mini-telemetry system for RC cars.
I installed the magnet on the rear axle, and glued the sensor to the rear of the gearcase. It works!
I narrowed down the front tyres to about 1.4 cm.
Titanium screws all over (when possible)
Pretty radical gear ratio: 1:2.52.
Global overview - for now
First test of the speed meter, placed on top of my workbench (no resistance, drag, etc... ) with a nearly dead battery: 166kph. Of course, this is completely free-running, and proves nothing. I need to get it out to my testtrack pretty soon.
To decrease wind resistance, I also added a new body: Audi R8C. It's a lot lower than other touring car bodies, so should inclease speed. I'm just not sure what it will do for my downforce... Some pics for now:
First Test Run
I gave the car a quick test run, I was too curious as to the result. Here it is:
(Picture taken with cellphone-cam...)
103km/h! I succeeded! Now I'm just going to see if there's any more speed I can get out of it. To do this, I will need to move the car's weight a bit more to the front, to keep the car more stable. I will design a custom chassis to provide more rigidity and probably add a 7th cell. I also need to add active cooling of some sort to keep the speedo cooler - after about half a pack it shuts down - overheating protection. Will also add an aluminium motor mount.
I also repeated the test of the free-running car, but this time I used a fully charged pack. The result: 190km/h!
I had one crash during testing, at about 80 km/h. Result: lots of scratches on the body and spoiler, and a severely damaged antenna pipe. Other than that the car was fine.
If anyone else has suggestions on speeding it up, please post them onto my forum, or send me a mail. Thanks!
Another global pic, also taken with the cellphone-cam...
Okay, got it up to 104 that time, check out the movie!
108kph achieved!
Some more improvements: I added my spare Spektrum receiver, so I can use the short antenna. This will lower center of gravity, decrease drag, and lose weight.
Top of the antenna sticks out just a little...
Looks a lot cooler without the antenna. The spoiler will be replaced by a lexan model to lose some more weight and hopefully add some rear grip.
Even more radical gear ratio: hoping to be able to hit 115+ with this...
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