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I just tested a new hydrofoil last night and it went very well.
About 4 months ago I saw a show on National Geographic channel called Mad Scientists.
The show is about a host which goes around to different garage invertors and challenges them to build something cool!
They usually show things the invertors have made in the past and this one guy made a small personal hydrofoil that used an outboard motor for power. He called it the Dragonfly.
You can find the videos on U-tube of the Dragonfly.
Besides looking like a really fun boat to have in full size I got to thinking it would make a fun model as well.
So I decided to make up some basic plans for building one.
Since mine is loosely based on the Dragonfly I have called my design the Firefly. As it is kind of a smaller version of the Dragonfly.
I was able to pull down some U tube videos and remove some stills to study. I also watched the show I had recorded about 20 times and wrote down and sketched all the info I could.
I also found out the inventors design was based on a Popular Science build how-to from back in the early 1960’s.
He just modernized the design and cleaned it up a bit.
I originally guestimated on the size and as it turned out the PS article showed I was correct.
The best thing was I was able to download the original article from the WWW and it had the plan for building the foils which really made the build a whole lot simpler!!
The foils were made out of shaped wood planks on the real boat and attached to the hull with hardware so they could be removable for easier transport.
It also made it easier to do as all the foils were the same size meaning I only had to make one then I could make a mold to replicate the rest out of Alumilite.
The scale size I chose was decided by the fact that a full sized GI Joe (1/6 scale) would look very cool and the EP-1 outboard motor would look the part perfectly.
This made the boat 8†x 16†as the real one was 4’ x 8’.
I did decide to lighten up the motor a bit by adding a brushless motor (former build) but as it turned out I don’t think I had to.
But I am sure it helped. The boat had no problem getting up on the foils. It was very stable and faster than I thought it would be.
I never actually adjusted the foil angle either.
The hull is basically built form a pink foam blank with plastic sides and fiberglass sheet deck.
One good thing is it can’t sink being a chuck of foam.
I had to lower the motor mount of the EP-1 motor as low as I could because it is not a long shaft motor like the real boat called for.
Obviously if you don’t get the prop down deep enough in the water the boat will not rise up on the foils very high.
As it turned out and you can see in the video it is skimming perfectly right on the bottom of the foils.
Although it did cavitate a few times and maybe running a surface prop might work better.
It was hard to keep the speed up when turning in the YMCA pool so the boat would fall off the foils in the corners.
It does the same thing in my other hydrofoil.
It did eat the battery fast as it also does in my other foil.
I use up a 2000MA pack in under 4 minutes.
But man was it fun!!
I will go into more build detail later but I just wanted to post the video.
I want to thank my good friend Paul who donated the Joe from his collection.
He even gave me one with Kung foo grip so he can hold the throttle and steering controls. Ha!! BD.
I just tested a new hydrofoil last night and it went very well.
About 4 months ago I saw a show on National Geographic channel called Mad Scientists.
The show is about a host which goes around to different garage invertors and challenges them to build something cool!
They usually show things the invertors have made in the past and this one guy made a small personal hydrofoil that used an outboard motor for power. He called it the Dragonfly.
You can find the videos on U-tube of the Dragonfly.
Besides looking like a really fun boat to have in full size I got to thinking it would make a fun model as well.
So I decided to make up some basic plans for building one.
Since mine is loosely based on the Dragonfly I have called my design the Firefly. As it is kind of a smaller version of the Dragonfly.
I was able to pull down some U tube videos and remove some stills to study. I also watched the show I had recorded about 20 times and wrote down and sketched all the info I could.
I also found out the inventors design was based on a Popular Science build how-to from back in the early 1960’s.
He just modernized the design and cleaned it up a bit.
I originally guestimated on the size and as it turned out the PS article showed I was correct.
The best thing was I was able to download the original article from the WWW and it had the plan for building the foils which really made the build a whole lot simpler!!
The foils were made out of shaped wood planks on the real boat and attached to the hull with hardware so they could be removable for easier transport.
It also made it easier to do as all the foils were the same size meaning I only had to make one then I could make a mold to replicate the rest out of Alumilite.
The scale size I chose was decided by the fact that a full sized GI Joe (1/6 scale) would look very cool and the EP-1 outboard motor would look the part perfectly.
This made the boat 8†x 16†as the real one was 4’ x 8’.
I did decide to lighten up the motor a bit by adding a brushless motor (former build) but as it turned out I don’t think I had to.
But I am sure it helped. The boat had no problem getting up on the foils. It was very stable and faster than I thought it would be.
I never actually adjusted the foil angle either.
The hull is basically built form a pink foam blank with plastic sides and fiberglass sheet deck.
One good thing is it can’t sink being a chuck of foam.
I had to lower the motor mount of the EP-1 motor as low as I could because it is not a long shaft motor like the real boat called for.
Obviously if you don’t get the prop down deep enough in the water the boat will not rise up on the foils very high.
As it turned out and you can see in the video it is skimming perfectly right on the bottom of the foils.
Although it did cavitate a few times and maybe running a surface prop might work better.
It was hard to keep the speed up when turning in the YMCA pool so the boat would fall off the foils in the corners.
It does the same thing in my other hydrofoil.
It did eat the battery fast as it also does in my other foil.
I use up a 2000MA pack in under 4 minutes.
But man was it fun!!
I will go into more build detail later but I just wanted to post the video.
I want to thank my good friend Paul who donated the Joe from his collection.
He even gave me one with Kung foo grip so he can hold the throttle and steering controls. Ha!! BD.
BD.
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