Scratch Build Foam Hull Airboat

[midnightsabotage]

Had lots of foam begging to be used, so I thought "airboat, why not?"

I'm very new to RC boating as a whole, but I'm very experienced when it comes to RC cars/trucks and fixing rc planes. (flying RC planes, not so experienced. Moreso, crashing RC planes... hence the fixing )

SO! Here we go. Most of it is done at the time of this post already, but it was a fun build and I'd like to share it with anyone who might want to see it.

I cut and sanded the entire main hull out of simple EPS type styrofoam. I prefer the catamaran style hulls and roughly shaped it as such. I thought it may turn better or handle better in the water than a flat-bottom airboat.

Here's an early picture:
Airboat 1.jpg

[midnightsabotage]

I wanted this to just be a fun project, and so I'm sure there are many things I should have researched and gone about a different way.
But half the fun is in figuring things out yourself!

Feel free to point out any major faults in my design, but do keep in mind that I'm going entirely off of what seems like it'll work in the mind of an inexperienced airboat builder. Oh, and I'm limited to the supplies and parts I have on hand that I usually use for plane repairs :p

So in that first picture you see I began with the pure foam hull, some carbon rod supports, and some random hard wood piece that the motor will mount to. I dug out an electronics compartment that will house the receiver, esc, and rudder servo.

Next up was installing some blind nuts and the aluminum motor mount. Then an additional carbon rod to support the motor mount piece (to make sure the motor didn't rip the stand out of the foam and bury the prop into the hull. I haven't yet epoxied the bottom of that 3rd support rod because I want to see if I have enough downward angle on the motor or not. I can adjust this angle depending on how far into that wood bracket I glue the rod in. (hope that made sense)

Underside.jpgCarbon Support.jpgMotor Mount Back.jpgMotor Mount.jpg

[midnightsabotage]

You'll see the beginning of the servo mount in that last picture.
You also might have noticed what was going to be a water rudder too, but I scrapped that idea. I had it set up and it would only really turn one direction well, and then I realized I'd rather be able to run this boat close to shore or maybe even get through some seaweed type areas, and so the water rudder idea had to go. It wasn't going to be very effective anyway even if it was set up well.

Well, moving on... I made a battery compartment a little further forward (seems to balance out right where the prop will be with all running gear installed, hope that's good), and since my hull is not very thick there, I made a cover for it, that might just act a bit as a spoiler to keep the front from lifting up too much. Made a inner lip and top plate out of balsa so that I'll be able to seal my electronics compartment too.

Decided to run the motor forwards because scale looks are not a concern obviously and the air rudder will be easier to set up and I won't have to worry about the cg hanging too far back. Plus that carbon rod support is right there.

Mounted up a 1000kv towerpro motor, I believe I can push almost 500 watts through it, 4s capable but we'll see how she does on 3s first. A Turnigy Plush 40amp ESC will feed it's power. I won't be running the 3 blade prop though, that was just for fitment to make sure I could swing a 10" propeller.

Rudders could be bigger, but that's the last of the sheet wood I had. We'll see how they work. I drilled out some balsa blocks to fit the plastic bushings for the bellcrank and 2nd pivot point for the rudders, then glued the blocks into the hull & soaked the balsa with foam safe CA. The rudders wobbled quite a bit at this point even though the "axles" and bushings were a good fit. I later went on to rig up some hinges on the top as well, and everything is now nice and solid.

I think that explains everything I've done with the current pictures I have here. I'll go through the rest of the build after I take more pictures of it's current state.
Rudders and Hardware.jpgMotor.jpg