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Brabham BT3

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I originally built this to compete in the 2020 Tasman Proxy series, obviously with all that has happened that didn't happen so with the 2021 series being planned I thought it would be a nice thing to get the car finished, 




Just a couple of the car.....


As in previous years the car features the FF050 motor with 9:24 off set SlotIt inline gears, Pauls tyres all round and all up it weighs in at around 55 grams.


Initial testing saw the car lapping around my place at 4.7 or so which although a little off the pace from 2019 still fairly okay, hopefully further tidying up may see the car a tad quicker.




Not too sure if this car will front the 2021 grid as I have a Ferrari 158 on the jig and that is now half done, 


Funny thing that once I got back onto the build I'm all refreshed and looking forward to getting the Ferrari done with a Honda RA271 also planned,


Hope you like the pics



Edited by terry
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No problems









Its a bit mucky, maybe I should have given it a bath before I took the pics!

Edited by terry
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Looking at the pics I should explain the idea around my decision to put in a pivot,


I was thinking that a little bit of flex would be desirable, although some would argue that these little cars don't respond to that I still wanted to see for myself with this build,


The pivot arms can vary in diameter and for this build I used 1.2mm thick piano wire, in hindsight I maybe could have gone down to 1mm diameter, I don't get too much movement in this chassis, certainly not as much as I was hoping for, although the car does run quite nice.

For an alternative feel I am in the midst of another build and in this build I will go for a 1mm torsion bar set up.

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Nice build, Terry...


I couldn't but notice that the red glow has started on those rear urethanes.

John Warren

Slotcars are my preferred reality

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Hi Terry, torsional flex in a chassis is a good thing, as it lets the chassis load progressively in a corner, and you will  find all "high end" scratchbuilt chassis incorporating it. It is equally important to engineer in the correct amount of flex, and as a general rule of thumb,.....the quicker the motor, the stickier the tires, the faster the track, the stiffer the chassis...With the opposite being true of course.

The FF050 motored F1 cars with their skinny tires, low powered motors, and,  racing on club tracks can be quite "soft" indeed, and to be honest your 1.2mm torsion bars are massively thick/stiff. I find that most of the scratchbuilt "Flexi board" chassis that I have seen in either proxies, club racing, or, brought into the shop, have been far too stiff.

In similarly motored chassis, I have never used anything thicker than.032 (.8mm) and this was with very long bars.....most typically I use bars between .025 and .030, depending on their length.


Chris Walker

A couple of shots of some F1 chassis using "thin" torsion bars...............these have all won the  proxies they ran in.









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