I’ve moved my project discussion from “Life goes on - Summer 2025” so as not to take it over.
To reiterate:
I’m getting older and pushing a wheelbarrow on my hillside property is getting more difficult. I could really use a powered wheelbarrow. I live in Chile and there is not a large selection of equipment available, and what is there is very expensive. So I decided to build something myself.
I modeled it on the DR Powerwagon.
The axle is the heart of this project. I started with a small van rear axle:
The axle is probably 3 to 4 times heavier than the Powerwagon aluminum axle. It is overkill, but on the other hand, it will be able to take anything I throw at it.
I had considered not using a transmission at all, but I really wanted a reverse gear in case I got in a tight spot with the cart fully loaded. An upside to this decision is that I got 2 forward gears and a dry clutch in addition to the reverse gear.
I wanted to use a driveshaft to get power from the tranny to the differential. I had considered a chain drive, but a driveshaft is cleaner and simpler. It was difficult to find suitable U-joints though. The tranny shaft is 25mm in diameter with a splined end. I couldn’t find any joints to fit this, so I cut the spline off and utilized the shorter shaft that had a key slot in it (not shown).
I found some ATV U-joints on AliExpress:
They had six spline male and female connections (smaller diameter than the tranny spline). I welded the female end of one to a chain sprocket (teeth were cut off) that had a keyed 25mm diameter bore that fit perfectly on the tranny shaft. The male shaft of the other joint was welded to a flat plate that was then bolted to the differential flange. Then the two joints were joined by sliding the male end of the tranny joint into the female end of the differential joint.
I do have some reservations regarding the U-joints. I’m sure they would be much happier with a higher rpm / lower torque application. I will have to monitor them and see how they fare over time.
Referring to the video in the first post, you can see I had a little trouble getting up the hill. I had a lot of wheel slip on the uneven ground. I had to lift up, unweighting the caster wheels to get both drive wheels on the ground. I think the design is fine for even, flat ground, but it doesn’t work well on my hill.
So today I tried an experiment. I removed one of the caster wheels and tried the hill again. The cart worked much better even with the offset single caster. The cart is back in the workshop now to change over to a single caster design. I had used the 2 caster design because I needed maximum stability for the hills on my property. But with most of the weight of the loaded cart centered over the axle, I think now the added stability of a second caster is minor.
I will repeat my probably deleted post. I would try to move the caster wheels back so they are behind the weight of the engine ie towards your feet. then the weight of the engine isn’t using the caster as a fulcrum point to lift the drive wheels up when it is unloaded. like drop a piece down from the tube of the engine mount to test it, and you will probably want to brace it if it works.
Ideally, you would put the engine under the cart like they have in the DR picture you show which lowers the center of gravity to reduce tipping and it is centered so the cart is pretty balanced on the DR. I don’t think you can do that without a different engine.
