Foamboard Air Boat on the Snow

Hey gang, with the winter now upon us I wanted to build an airboat from parts i had laying around. This is what I came up with. and It can be built from only 1 sheet of foamboard. I am running this off a 24g hextronic motor, Same one that FliteTest uses for most of their earlier planes, like the FT Flyer, Nutball, BloodyWonder etc. I'm using a 10amp esc, as thats what I had laying around, anything will do. a 2200mah 3s, but you could use a smaller battery. not sure how a 2s would go, but a 3s definately wasnt too heavy and it had a lot of punch. I was using an 8x4 prop. This also works with a smaller prop of course, i just had some 8 inch props laying around.

I started off modeling it roughly in 3D, to get the rough shape i was after, then i tweaked my design so that I could use 1 sheet of foamboard!!

Firstly start off by downloading the plans and transfering them to your foamboard.

AirBoat Plans

Start out by cutting out your Hull and your Cross Braces. Tape the underside of your Hull first, I used duct tape along where my corners were going to be and a strip down the middle (I was rnning low or i would have used more) I then covered the entire bottom in packing tape for slipperyness over the snoe. Then cut along the score lines on the Hull and do a slight bevel cut. (I just mashed it in with a bbq skewer, but it would have been much easier to do a 45 degree bevel cut) Then glue in the Cross Braces into place.Line them up so that they are both on the rear side of the reference line. you could have it infront of the line, just make sure both are the same.

Now by adding a lot of hot glue, fold up the sides of the Hull to meet the Cross Braces, once they are in place glue the front, corners and sides together. You want these to be strong so dont skimp on the hot glue.

Now cut out the motor mount sides and test fit them to make sure they fit. I forgot to add this in the photos, but glue on the motor mount and the motor mount brace  to the top to help it stay square. Then glue it in place centered across your Hull. Lots of hot glue again. we dont want this coming loose.

Cut out your Top Deck and cut 45 degree bevels  at the front of the hatch and at the rear fold down pannel as indicated on the plans. 

Tape up the whole upper deck I used Caution tape as its bright and easy to see it racing across the white landscape.

Now you want to glue the Top Deck to the Hull. Once its in glue down the rear fold down part into the fuselage, this is to help the air flow get from the prop to the rudders in case you're using an 8 inch prop

This is what it looks like from the back once you've glued on the Rear Wall. Tape up everything!!!

For the rudders I planned on having it driven by 1 servo with a connection between them. This didnt work well at all as when you pushed the rudder the linkage in the middle would shift and you wouldnt get a good push. You'll notice 2 braces between the rudders, these were placed with the smallest amount of glue possible, just to keep the spacing even between them and to keep them both square. the glue easily came off with a bit of pulling once they were installed

I eneded up using a y harnis between my two servos. if you choose to use 1 servo you can just plug it straight into your receiver.Glue on the rear tail assembly. Pretty close should be good enough. 

And here it is finally built. I planed on putting the battery up front with the receiver, but the CG for an airboat needs to be 30% from the transem. (aka the back of the boat) So I had to stand the battery up next to the motor. it hasnt gone anywhere in any crash of mine and its only been held on by velcro. For extra strength I've 

After a small sideswipe with a tree the rear tail assembly came loose. as hot glue, tape and cold weather dont mix. I fixed this by putting some bbq skewers down the leading edge of the rudders and the tail assembly and embedding them through the top deck and partially into the hull underneth. added a bunch of hot glue and this tail is super strong, its not going anywhere.