Ok, so we may have made our kart design a little Big. Unfortunately, we are stuck with the design now as the rules for the Red Bull soapbox states the exterior look of the vehicle must remain the same. The chassis can be changed, but overall length/ width has to remain the same.
The first drawing is an overhead view of the basic layout of the floor chassis, seating arrangement, and somebody bits. Thanks to your advice from an earlier post, wheels will now be 14'' pit bike wheels instead with 15mm axles. Stub axles we plan to use. Cant show the steering parts as I’m not sure of their dimensions fully yet.
Aerodynamic drag is by far the largest factor affecting a carties top speed, but how big an effect is it? I've been doing some maths and have come up with some interesting typical figures. The three sources of drag on a cartie are;
- Aerodynamic drag
- Rolling resistance
- Wheel inertia
Rolling resistance is almost constant at all speeds, and wheel inertia actually decreases as speed increases (or - more correctly - as acceleration decreases), but aerodynamic drag increases as the square of the speed. It starts off very low, but soon becomes the dominant factor.
It seems to me there are a few things that people commonly do when building their first cartie which, with the benefit of hindsight, they probably wish they hadn't done. Here are a few of the common "learning opportunities" I've spotted;
At the risk of giving away all my secrets... here are some of my favourite places (mostly on eBay) for finding parts for my carties;
Bankrupt Bikes - forks, wheels, frames, swing arms, etc.
Kart Parts Direct - track rods, steering columns, etc.
Bike Bits and Leisure - another good source of 20" BMX wheels on 14mm axles
Kart seats direct - Caliba Kart seats
McGill Motorsport - Huge range of rose joints
Bike Care - dual pull brake lever
Small Bikes NI - drift cart "butterfly" steering wheel