These are instructions for the basic components of constructing a kart on which to mount an engine, in this case I used a miniature jet-engine that I had previously created, and therefore those instructions will not be included in this, but rather will be linked to below.
Step 1: Acquire Jet-Engine
To build a Go-Kart powered by jet engine, naturally it would require you to have a jet engine available to use. This is not a very common thing to have laying around in a garage, so more likely than not you will need to make one. I have another Instructable posted with the instructions of how I build my jet engine using a turbo charger. If you want to try and build your own of this project that would be the place to start. Rather than go through all of those steps again, there is a link to my previous upload included in the introduction.
Step 2: Designing the Frame
Excluding the propulsion system, the most central part to this and any vehicle is the body as it must support all of the other components and the operator. For this frame I started with ---foot sections of steel with a 90 degree bend and two pieces of 3 foot, 1/16 inch thick steel square tube. This is somewhat thin an because of this rather difficult to weld as you can easily melt straight through it. Ideally I would use thicker (1/8 in by 1.5-2 in diameter) stainless steel round tubes for the frame, but due to budget constraints (I don't have much of one left) I cant do that. With carefully welding, and more reinforcements the thinner regular steel will work fine.
I took the longer steel bars with the bend in them and laid them out in my work space, with one side laying flat, and the vertical side on the outside. (This can better be seen through pictures). I have these two longer bars parallel and 2 feet apart. I then cut 1 foot off of each of the 3 foot square tubes, so that I had 4 pieces total, 2 at 2 foot length and 2 at 1 foot length. I then laid the 2 foot sections in between the longer bars, perpendicular to the bar and parallel to each other. I have the tube sections set in about 8 inches from the edge, so that the longer sections stick out past the shorter ones on both sides.
This makes up the initial layout for the frame, however for any structural integrity to be maintained additional cross pieces need to be added. I chose to use more 90 degree angled bent bars, cut to form triangles to strengthen the frame, and flat bars welded to these triangles to provide a surface on which to mount the various fixtures of the kart.
Step 3: Wheel Assembly/Axle - Rear
Because the main propulsion source for this vehicle is jet propulsion, for the rear I used none moving axles held in place with locking mechanisms that hold the axle, bolted through plates attached to the frame and wheels with bearings inside of them, allowing them to spin freely on the axle. I used 1 foot long by 2 inch wide by 1/4 in thick bars of steel as the places through which to drill holes allowing the locking parts to fit through. These bars were welded to the thicker 90 degree bend steel sides of the frame, as it gave a long surface to weld to, allowing for a strong bond.
Step 4: Wheel Assembly/Steering System - Front
The steering system operates using free spinning wheels on either side, mounted to pivot points on either side which are then attached to the rods connected to the steering column. The pivot points have a shorter axle, 8 inches attached them, one on each side, for the wheels to sit on. The pieces that pivot with the axle rods attached to them are 4 inches long, with a 1/2 in hole in each side of the, through which, on one side a 7/16 bolt runs all the way through the body and bolts the pivot point to the chassis. Through the other hole, a connecting rod is bolted on, which allows the pivot point to me manipulated via a side to side motion of the rod, and this is done on both sides. The inside ends of these rods, which are the parts that connect to the steering column, are then connected to each other by a 6 in long flat metal bar, with holes in the either end to accommodate bolts. This makes it so that when the center point of this bar is shifted side to side, it shifts the rods side to side, and thereby turns the wheels. The last part of this is to set the steering column in place, and use one last flat steel bar, connected through a hole in the center of the plate that is attached to the rod, to connect the column to the rods. This last bar of steel acts as a level, when it is rotated about one end point, the end attached to the steering column, it allows the opposite end point to move side to side a few inches either direction. This provides the sideways motion needed to shift the connecting bar between the rods, and allows the steering column, and therefore the steering wheel, to turn the wheels.
Step 5: Mounting the Engine
This is actually a rather simple step, if you have no intentions of removing the engine and remounting it to something else at any point. On my engine I have a base plate made from 1/8 in thick steel, and I chose to simply weld this directly onto the back of the kart, where I had made a platform for it. Ideally in mounting the engine, you would want to leave a space for the fuel and oil tanks, and the pumps for them to fit close by. I have a gap behind and under the seat open for this purpose, but as the design of the frame is rather flexible, it would depend mostly on how the frame is built.
Step 6: Attaching the Seat and Additional Cross Pieces.
Right now, aside from the supports on the ends that brace the areas where the wheels attach, there is no support to hold the center together, and prevent flexing and bowing. This must be added for structural integrity and also as a location to mount the various other parts of the vehicle, such as the seat. There is some variety to how this can be done, for example, using triangular structures provides the most strength, and having tubes or angled pieces rather than flat bars will prevent sag across longer pieces. Using cross pieces that just lay perpendicular to the sides of the frame also has its benefits, as this allows square components such as the seat I have to be attached more easily. This is what I chose to go with, while also reinforcing it with triangular pieces. I used 90 degree bend steel bars with flat bars laid next to these, welded together along their length, and welded to the frame at the ends.