New car project TC6-C
 

I've just about finished the design for my new car project, thought I'd post a pic before I make the first prototype as I'm sure you guys will spot something I've missed ;)

The aim of the project was to centralise the weight in both X and Y directions, without raising the CoG or comprimising the suspension or chassis flex, which are key parts of TC design. Every manufacturer that's tried to centralise the mass has pretty much failed, primarily because it's not really possible with a full-size Lipo. But with shorty lipos it's finally possible to meet all of the requirements without comprimise.

The end result is that the overall weight is more compact in all directions, and the CoG is actually lower as the motor can sit right down into the chassis. The symetrical design also makes for much more even corner weights. And the motor torque reaction is more central, although I'm not sure that's significant with lightweight brushless rotors.

Okay, I know some are going to say "oh my god its got 3 belts it will only do 2mph". If I was racing slow blinky classes this might be a concern, but I run boosted, and with boost the car is still accelerating at the end of the straight. So the speed of the car is mainly determined by car weight and motor torque, not minor variables like belt drag.

The suspension, steering, main bulkheads and diffs are all standard TC6 items. The motor mount, layshafts, layshaft mounts etc are off various other cars (mostly XRay T2 and T3R; XRay change their car every year so they have a nice parts bin to choose from, and the old silver parts look fine against the TC6 blue :D).

The next stage is to make a prototype fibreglass chassis to confirm that the WD is as expected and that everything fits fine. Then I'll get Fibrelyte to make the final carbon chassis and top-deck (the top-deck isn't in the attached image).

http://www.rc-timing.com/other/TC6c_Layout1.png

Looks Good! Keep us updated on how the prototype runs.

go for a E4 instead of TC6.
E4 is much closer to your design....

How do you plan on running a topdeck with that layout Dale? I mean the layshaft mounts are inline with your bulkheads so will cause an obstruction unless you will be running them at a different height to the main topdeck or are you going for a tub chassis? Also what about symmetrical chassis flex, you will have more hardware fixed to the right hand side of the chassis.

The plan is for the top-deck to go over the layshaft mounts and motor mount, without bolting to them. The XRay mounts are very low (about 22mm high) so will be miles away from the top-deck (30mm high) and not interfere with it. On the TC6 I don't run the bolts into the layshaft mounts, so the new car will use the same number of top-deck bolts as the TC6.

Symmetrical flex is certainly a concern, and is something that will need to be checked on the first mock-up. It should be possible to measure it using clamps, ballast and a dial gauge. All of the mounts are as short as possible, and are not bolted to each other, so I'm hoping the effect will be minimal.

I would love a carbon tub chassis, as it makes sense with the motor moved inboard, but it's a bit outside the budget :cry:

I've now got the first draft of a top-deck (image attached). Still needs to be made a bit prettier, and I think it's too wide at the front and too narrow at the rear, but it shows the general idea. The top-deck goes around the motor and over the top of everything else.

When drawing this I realised that I needed to lower the front layshaft so that the top-deck could go over the pulley, otherwise I ended up with a very narrow, ugly top-deck at the front. This also has the advantage of lowering the CoG, and I moved the layshaft mounts slightly to fit a U-shape lipo holder, keeping things more symmetrical.

I also narrowed the chassis to 88mm (the previous design was 92mm, the TC6 is 96mm), which should give a lot less rubbing than a standard TC6.

The weather looks to be warming up so hopefully start construction soon :nod:

What's a sentry?

Novak Sentry data logger. Records motor RPM, current, voltage, G-force and some other stuff. Can also be used to get laptimes for practice sessions which is perhaps the most useful feature.

So a useful bit of kit that I wanted to make sure would still fit.

what software do you use for those drawings?

Draft It from here:

http://www.cadlogic.com/cadsoftware.aspx

There's a free version that works well for basic drawings. The upgrades are well worth it to get layers, views, exports and more advanced drawing features.

My 5 cents:
- search for Qcad (dxf files),
- 3d t-flex (it has Student license, just register and download).

Draw 2d files in Qcad, in t-flex build 3d models, connect parts ;)
2d dxf files can use for CNC job. (My F1 are done like that)

Simple and "no money" ;)


Anyway, I wait for final product and some info from tests, how it works.
And how it made faster driver.

Regards!
Michal

Finally got started on the construction of the TC6-C. Quite a productive day, got the mock-up chassis drilled and cut, as well as the carbon front layshaft brackets done (used to lower and offset the layshaft). Also trimmed the Xray bulkheads and motor mount to size.

Doing a mock-up has already proved beneficial; the motor mount needs moving by 2mm to get the motor CoG onto the centre line of the chassis (hence the spacers in the picture between the motor and the mount).

Next stage is to sort out the layshafts and pulleys properly (I don't think BluTac will quite hold up on track ;)), then create a jig to test the chassis flex is even left to right. I doubt it will be; the plan is to create some cut-outs around the layshaft bulkheads to put some flex back into the right side of the chassis.

A few more pics. I'm keeping the TC6 single-point steering for now, just using a post attached solidly to the chassis with no attachment to the top-deck. Mostly because the top-deck won't be going over the top of the steering post!

Good luck!

this fiber glass was cut on cnc?

ps: It's pushing me to made home cnc ;)

With the placement of the motor and rear pulley assembly, it appears that you will be very limited in the amount of space for motor adjustment/gearing selection.