Tuesday, 13 May 2014

Lates update for the SV-10 II

I have gone back to the original plastic suspension blocks instead of aluminium because after a while, the suspension pins will stick with the aluminium pieces and will be almost impossible to remove them, so its back to short camber links. I also re designed a version 2 chassis to fix the problems the first version had.
I also reduced the chassis width from 90mm to 70mm, increased thickness from 2.1mm to 2.4mm, and changed the battery mounting. The result is a narrower, stiffer chassis, with VBC modern floating servo mount, to allow the chassis to flex evenly both ways. I also finally figured out what was wrong with my rear TRF 417 gear diff with steel gears. The steel gears were beginning to grind each other, so I tried putting plastic gears for the outdrives and using steel for the small gears, it worked like a charm, the diff is now super smooth. Tested the car yesterday, and with all this new innovations added, the car handled like a dream yet again.
Probably the biggest difference was the flex characteristics. So how does it drive really?
The front ride height is 5.5, and the rear at 6, with the rear having more droop than front. Front springs harder than rears. I found that the car is very stable and transitions very quickly in sudden turns, sometimes it feels unstable in one particular turn, but however my worries are unfounded as the car still held its line well even with the old tyres. At certain corners the car understeered off power but this is probably the track surface which gave a lot of traction at that area. In a nutshell, the faster I nailed the throttle, the more it understeered, the slower I went the more the steering. This is how I like my car to handle, stable and easy to drive. The flex is now even on the left and the right, and this design has really paid off. I studied this layout against some other centralized designs by ds24, daleburr and a german guy who centralized his HB TCX , and found that they made fundamental mistake in the motor mount. In order to centralize the motor, they mounted the motor mount on the right side. This limits the flex on the right side, and also the middle belt would tweak the chassis under acceleration and braking, that's why most of these designs dont work so well.

Top view

The VBC floating servo mount, notice it overhanging from the narrow chassis.

The belts and diff had to be flipped because the servo and esc had to change sides.

at the track before testing

Just before I scratched the chassis. Look at all the screws position, notice they are completely symmetrical. This ensures the flex of the chassis is symmetrical and even.

Its always satisfying to get a great result out of one's own design. This car drives like a dream.


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