We have been on an Alaskan cruise for the last two weeks. This was our first cruise and we had a great time. I have always thought of Alaska as a wild exotic far away place, a frontier at the edge of no where. It is! We flew in a plane over Mount Mc Kinnley, went whale watching, flew in a bush plane to watch the bears dine on the Salmon run, road a boat on a glacial fed river to view Eagles and Moose. We saw glaciers and Sea Lions and snow capped mountain ranges. But one of the things that I found most interesting is panning for gold. We visited a gold mining operation that was also used as a tourist attraction designed to familiarise you with gold mining. After a short train ride through the mine there was a demonstration on sluice mining method after which we were each given a small bag of pay dirt to try and remove the gold from the dirt and rock by means of panning. Gold is at least 10 times heavier than other rock and minerals so the idea is to wash the lighter rock and dirt out of the pan and leave only the gold to be harvested. I got most of the lighter minerals and rock out of my pan and then let one of the experienced assistants finish the final panning. Here is what gold looks like after panning. These are flakes of gold but no nuggets. But gold is gold. I now understand what "Gold Fever" means. I am ready to stake a claim somewhere.

It has been a hot summer so far and the heat makes it difficult to work in the garage with my small fan. Twenty years ago that would not have a lot of effect on me. But this is not twenty years ago so I have learned to pace myself.

We have come to the point in this project where we must decide exactly how to transfer power from a gasoline motor to the drive sprockets and chain. There are many options to be considered and I have thought about them all or at least as many of them as I know about. The main ones are as follows:

1. Friction clutch with chain drive.

2. Batteries with electric motor drive.

3. Hydraulic drive.

Each method has its' positive as well as negative features. We could have a really long dialog about all of the different methods and how to achieve them but I am not an expert so I will list the criteria that I am trying to achieve in this project and some of the reasons for my choice.

I would like to achieve the following:

1. Moderate speed and power. ( what does that mean?)
2. Efficient speed control.

3. Smooth power transfer from engine to drive train.

4. Easy and efficient reverse.

5. Good brakes.

Using a friction clutch that attaches to the engine shaft would be the most simple way to go but then there would be no simple way to incorporate a reverse of course unless you want to buy an expensive reversing gear box. If you just want something that goes forward and goes fast then the friction clutch or torque converter would be the way to go. But I want this cart to travel at a safe speed for beginners and have a way for them to back up without having to get out and push the cart backwards. This could be achieved by using a transaxle and transmission from an old riding lawn mower but I want a little better performance than that would supply. Besides we are a little past the stage of easily incorporating a transaxle into our design. I like the idea of an automatic transmission. Hydrostatic hydraulic drive for tractors and lawn mowers is an efficient way of eliminating gears and special clutches from the drive system. Basically you just push the accelerator pedal forward to go forward and push it backwards to go in reverse. I have decided to use my limited knowledge of hydraulics to build a drive train from readily available common components in order to achieve the goals listed above. I have tried to research this method on the Internet but cannot find very much where this method has been used for a go cart. Most of the time that means it probably is not a good method. But I like a challenge. I suppose only time will tell if it works well or not.

The first thing that needs to be determined is what performance criteria you are looking for. Then you must choose the components that will both meet those performance requirements as well as work in a balanced proportion with each other. The following rough sketch is the basic set up for our system. I will probably need to make changes as the actual fit up of parts continues.

The following photo shows the individual drive components.

The following is a disc brake that will be incorporated into this cart. It came off of a prior project that I plan to rebuild in the future using the drive axle from the old golf cart I disassembled.

The following photo is the hydraulic motor I have chosen. It is described as a Dynamic low speed, high torque hydraulic motor. 11.85 GPM( gallons per Minuit) 2050 PSI. It has the following performance and dimensional specs:

Fully reversible, 4 bolt mount,1 in. x 1 3/4" long shaft has 1/4" key way, 1/2" NPTF( national pipe thread female) ports. Orbiting gerotor principle. 880 maximum RPM. Maximum torque of 885 inch pounds. Maximum flow of 11.85 GPM. It weighs 13 pounds. It is available at Northern Tool under item# 1040 and costs $180.00.

As you can see it is an expensive item. But it does take the place of friction clutches and other secondary gear reduction. For anyone who may be interested I will give you the calculations for the hydraulic drive system later on.

I plan to use a good Honda gasoline motor that will start every time you pull the starter rope. I would like to have an eclectic start but I figure that the girls will only ride under close supervision so there will always be an adult to start the engine. When they get older they will be able to start it themselves. The plan is based upon the power of a 5 horse power engine that has a maximum RPM of 3600. I am concerned that 5 h.p. may be a little underpowered so I will have to do a little more thinking on this.

The following is what is referred to as a Love Joy coupling. It is a flexible joint used to connect the hydraulic motor to the jack shaft that turns the drive sprocket. The white part is a hard rubber cushion that absorbs shock from the torquing of the motor input shaft. You cannot tell it from this picture but everything has a 1/4" key way to hold it stationary on the shaft.

Here is the 1" jack shaft or drive shaft that will turn the drive sprocket and also the brake disc. In this picture I did not have it turned so that you could see the key way but it has a 1/4" key way that runs the entire length of the shaft.

We will use two one inch pillow blocks like this one to support the shaft.

The following shot shows the components as they will be oriented in their final orientation. Yeah my writing skills are really on it today. The brake disc on the end of course will be turned sideways so it can slide onto the shaft.

The first thing we need to do is build a mounting bracket for the hydraulic motor. As you can see the motor is designed to be mounted using four 3/8" bolts. The shaft is one inch diameter but there is a raised step on the outside that measures one and three quarters diameter. I do not have a 1 3/4" drill bit and they are expensive. Besides it probably would not fit in the chuck of the drill press. So what do we do.

Thank goodness for the bi metal hole saw. I am amazed at how easily it can cut through a 1/4" thick piece of plate steel.

You will need to find a way to bolt the mounting plate to the press while drilling the hole. I am using machine blocks with clamp straps because I have them available in my shop at work. But you can use large C clamps or vice grips to hold the piece in place while it is drilled. Remember to use WD 40 or some kind of lubricant to reduce heat and friction.

The hole saw makes a surprisingly smooth cut. Of course it was brand new also.

Either I was a little off on the center hole or on the mounting holes. I will need to use a round file to wallow the holes a little to make them fit. I was just guessing at how long to make the mount. I have not decided whether this will be welded in place or bolted on. We can always weld on another piece such as a piece of angle iron if needed. We now have a mounting plate for the hydraulic motor.