Hydroplanes are fascinating examples of what happens when boats and planes collide. Here's how I designed one.
A hydroplane is, in essence, a very fast boat that skims across the surface. They usually use hydrofoils or a stepped underside to plane on a body of water at extremely high speeds. I've always been intrigued by them. Back in the day so were thousands of other people. At the same time as the golden era of flight was raging, powerboat races and world record attempts of the 1920s and 30s were setting a new precedence for speed.
These beautifully designed machines were smashing word water speed records in access of 150mph.
Although RC boats are a whole other hobby, I think there's enough overlap with the RC airplane world here. For one, many of these old hydroplanes were built like airplanes. They were light, constructed in the same way and often borrowed components. For example, the jet-powered boats of the 1950s and 60s used turbines pinched from state-of-the-art jet fighters!
So, what am I planning on doing? Well, being the mad scratch builder that I am, I've decided to build a model hydroplane using aircraft parts. This isn't anything too revolutionary, however, as I did something similar in 2017.
Last summer, I built a hydroplane based on a famous real-life craft called Bluebird K7. You can read more about the real story of Bluebird here.
This model was powered by a 3000kv 64mm ducted fan and a 4s battery. It worked fairly well in the end and looked quite impressive skimming across the water. However, I knew I could improve upon the design in so many ways.
Skipping forward 9 months, I've now started to build another hydroplane - and it's going to be awesome.
This thing is going to be powered by two counter-rotating race quad motors positioned above the main hull of the boat. I'm doing away with an EDF for now as it seems that you can get more thrust by exposing the motors and props. This also gives me some flexibility to experiment with thrust angles. An adjustable motor mount will be secured to a pylon. To get the right thrust angle, I'll be able to move the mount around.
The hydroplane will be made almost entirely out of wood with a few carbon parts here and there. This gives me the ability to seal the whole thing with boat varnishes whilst leaving a nice looking wood grain finish.
The inspiration for the configuration of this design came from a YouTube video of someone else's hydroplane project. This thing is absolutely insane. It reaches speeds in excess of 100mph and has a carbon fibre hull. Before you do anything else, you should check it out.
The next step in this project will be to crack on with the build to get everything moving. Be sure to check in for the next instalment in this hydroplane series in a couple of weeks!
Article by James Whomsley
Editor of FliteTest.com