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Micro Hydrofoam project. Just 35CM long and 140 grams my first attempt at this type of model
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Published
Apr 02 2013 by FaTe
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Big thanks to www.FrSky-RC.com for providing the Receiver unit for this project :)
/imgs/Hydrofoam/1-depron-hydrofoam-base
The base of Hydrofoam was designed using existing models out there as a basis which all seem to follow the same basic shape for both the top platform and sponsons.
/imgs/Hydrofoam/2-carbon-supports
I'm using 3MM depron so I added in carbon fibre strips 2MM thick across the length of the fuselage to support it.
/imgs/Hydrofoam/3-elevon-servo-placing
The elevon servo is sunk through the fuselage to the bottom so only the head is on the top.
/imgs/Hydrofoam/4-electronics-installed
The engine mount is just depron layers built up. I just guessed with the size of the fins I figure tall is best for increased stability.
/imgs/Hydrofoam/5-RX-servo-bottom-pod
The receiver also sits on the bottom inside a balloon which comes through the top. Both the servo bottom and RX are sealed in with a pod water proof.
/imgs/Hydrofoam/6-carbon-skid-plate-protection
Hydrofoams are designed for use on the ground as well as water and flying so I added some carbon fibre skid plates to protect the depron.
/imgs/Hydrofoam/7-control-lines-fitted
All the control lines are fitted using my normal carbon fibre + heatshrink pipe method. All electronics with exception of the motor (which doesn't care about water) are sealed either by glue or inside balloons.
/imgs/Hydrofoam/8-float-and-angle-test
The last thing to do was test how it sat in the water. It's important to know your propeller won't hit the water and that it points slightly upward to help lift out of the water and lower the speed required to get airborne.

As you can see the model sits very high and hardly displaces any water at all, which at just 140 grams AUW isn't so surprising. Although you can't see the pod on the bottom where the RX is I did check and its a good 2CM off the water level, even though it's water proof is best to avoid contact if you can.
I know for a fact I've made life difficult for myself building a Hydrofoam for the first time in this size. While I know it'll work on water and on the ground (did some tests inside) how it flies is what concerns me, it's so small which usually means twitchy to fly.

I will upload a 2nd part to this project once I get a chance to maiden all these new projects!
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