I've been using apm and now pixhawk for some time in both fixed wing and copters. My latest build is an arduboat using a modified off the shelf rc boat with an intelliducer for lake surveying. I'm now planning my next build. I will be operating the craft in remote areas (several days drive to any gas or electricity) for up to 2 weeks at a time. That got me thinking of possible using a gas engine on the boat to eliminate the need for a generator. Having a gas motor would reduce the support equipment needed for these long duration survey projects.
I've never used liquid fuel engine with the apm or pixhawk and i'm sure i'd need to dampen vibrations and such, but what other considerations are there? I'm looking for a minimum 6hr endurance for the boat between recharges/refueling. Has anyone measured the fuel consumption of the rc gas motors? Just wondering what the community thoughts are on the best approach.
A six hour endurance requirement can be met probably with careful throttle control management.
My VBox Crackerbox hull is 46 inches in length and is designed for a 26cc Zenoa gas engine using a large fuel cell of around 27 ounces Link which might give you around 1/2 hour of run time at moderate speeds. Now this hull is a racing hull, but you could reduce the speed of the engine to conserve fuel and add more fuel cells for additional capacity.
If you envision a smaller hull, you could go with a smaller engine to conserve fuel and possibly attain your requirements.
Thank you for the reply, I've been following your projects with great interest. The hull will be of my own design in a trimaran configuration. The final size largely depends on the space needed for fuel, be it of the liquid or electron type. That is an interesting motor, I had no idea that the rc motors have come so far. I've been all electric in my hobby for almost a decade now. Perhaps a smaller motor with a reduction drive would get the final rpm needed and be fuel efficient.
A big reason to stick with electric is the simplicity, fewer links in the chain than a gas system. being able to field repair/replace components is a core design goal. More research is needed to make an informed decision.
Have you seen my conversion of the VBox Crackerbox from gas to electric brushless propulsion Link ?
The brushless motor is around 3 hp and with two 10,000 mahr 6S LiPos might get around one hour of running time at slow speeds and maybe 1/2 hour at its rated speed of around 25mph.
Tom C AVD