The airboat with a .40 sized engine and a 3-blade pusher prop. Click to enlarge.
This was pretty much a random weekend project, but it ended up actually being a lot of fun. It's
basically just a mini powerplant bolted to some foam, but it definitely gets going on the water. It doesn't
break any speed records, but it's pretty amusing to drive around on your average peaceful parkside river.
You can check out the video here.
The initial twin-hull design with a single 2-blade pusher prop.
At first it had some serious hydrodynamics problems where it would create fountains of water at the tips of the two catamaran-style hulls. Also, the wood prop we had would suck water in and cause it to splinter under as it impacted the water droplets at high RPMS. We thought we could fix these problems by jamming a piece of foam to give the whole base a flat bottom which would keep it higher out of the water. Unfortunately that was almost a disaster, as it had a nasty tendency to nose into the water, trying to submerge itself. In a last effort, we hastily removed back section of foam underneath the rudders in order to get the nose higher out of the water. The difference was amazing!