After reading a bicycle-powered hydrofoil build we posted a few days ago, [James] sent in the project that earned him an iron ring from Dalhousie University in Nova Scotia, Canada. It’s a pedal-powered hydrofoil made of carbon fiber and a Titanium drive shaft [James] and five other students in a mech eng senior design class built in 2005.
The Halifoil, as the team called it, is based on a recumbent design and uses twin carbon fiber hulls to keep the rider out of the water when not pedaling. The use of carbon fiber foils and Titanium drive shaft keep the weight down so the rider can easily accelerate to a speed where the hulls come out of the water.
Compared to the last hydrofoil we posted, [James]’ build is much heavier, but one is much better suited to sitting in the middle of a lake, then pedaling to the shore while flying above the water.
Even though the project is several years old, it’s still a very cool build. [James] was kind enough to post the videos of his build residing on the Dalhousie servers on YouTube; you can check those out after the break.
[youtube=http://www.youtube.com/watch?v=EJ6NwbaAU4w&w=470]
[youtube=http://www.youtube.com/watch?v=Gckjfdinbp8&w=470]
From the videos it looks like a lot of pedaling to get “foilborne”. Once “foilborne” is there a decrease in drag? (I mean what is the benefit of hydrofoils? more speed/less drag? I am aware of the smoother ride resulting from not “riding the waves”, is that the only benefit?)
Drag is greatly reduced because your wetted area drops from the hulls to just the hydroplanes – so you can go much faster, assuming your power source holds up. Thus, hydrofoils are the fastest commercial/military watercraft on the planet. Apparently attempting to beat the water speed record has a 85% fatality rate.
It is much bigger in the video than it looked in the still picture. Did the hulls need to be so big to keep it afloat? It seems they could have been smaller and sealed and they would float just as well.
Also, the gear ratio seems to be off. It looks like it just barely gets out of the water by the time you reach the end of the pool.
One last thing, what is the deal with HaD putting names in brackets? [James] is hard to read. Just type the person’s name like the rest of the words. Is a name really so unique that you need to put brackets around it so that you know it is a name?
Years ago, I rode a Hydrobike(TM)http://www.funwatercraft.com/ It was a great pedal powered watercraft. And it was “a lot of fun” to ride.
Not that I’m nay-saying the pedal powered hydrofoil, I think the Hydrobike is worthy alternative.
Product placement now?
Suggesting an alternative that is easier to get up and running and to use is now considered product placement?
“Our water bike is almost silent to operate, making it also great for trolling.”
I see what you did there…
+1 Mac
No, I’m not connected to Hydrobike in any way,
but I would like to own one some day!
“One last thing, what is the deal with HaD putting names in brackets? [James] is hard to read. ”
Just them trying to be hip and Uber.
Actually, we do this because often the names are not easily distinguishable.
What’s with the bike helmet in the pool? Is he afraid he is going to go so high he is going to hit his head on the flags?
I personally like the names in brackets, it’s much easier to see when quickly skimming an article
The Pump-a-bike looks like much more fun, and a whole lot less work. It’s also commercially available.
Not to pooh pooh an engineering project, but this doesn’t look as efficient as it could be.
you have got to haul ass to get that thing up
On the topic of man-powered foils – see also: http://www.youtube.com/watch?v=9BXxL9gztO8
Reaching way back in time… i remembered a “beyond 2000” episode with a pedal powered hydrofoil. they had it race an olympic rower.
skip to 4:12 for start of hydrofoil and about 6:00 to see it race. This was from way back in 1993 i think.
http://www.youtube.com/watch?v=Ts5WChFnzRI
When we are taught to fill in little boxes and fill in lines with text or stay in lines, it’s hard to think outside those constraints. This is what I felt when watching the trial in the pool. Forget about the salad bowl-helmet. With not enough run to get it up, they simply could get more length by running diagonally. That’s crossing the lanes, omm. And a push off or rope pull would let us observe the lift phase, that’s cheating omm. Not sure weather it academic or jock thinking here. Exploring happens outside these limits, even in the limit of the pool.
I [James] would like to respond to a few comments about the project:
The engineering department required a lot of convincing before they allowed us to take on this project. One of the conditions was the lifejacket and helmet. Probably overkill, but that’s how it was. We had limited time for testing, and the pool specifically refused to remove the lane-lines and bulkheads. It was also March in Halifax, so testing outside was out of the question.
Our mark in the course was largely determined by the project’s success. In our case, success was solely determined by the hydrofoil becoming foilborne under the rider’s power alone. This influenced the design heavily: we didn’t aim for top speed, just a boat that comes out of the water reliably. As it turns out, the top speed was about 20 km/h with a fit rider, which is comparable to a rowing eight with a good crew.
Faster designs are certainly possible (e.g. the MIT decavitator), however the failure rate is quite high. For example, around the same time (2005), the University of Illinois spent several years developing a design with state of the art design, simulation and fabrication. Their design team was large, included faculty members and was well funded, but the hydrofoil did not lift off. I’m not sure if they continued and eventually succeeded or not afterwards.
In contrast, our project was designed in one semester, then built, assembled and tested at full scale the next. The total budget was less than $2500 and the whole team was five undergrads with full course loads. The entire design was built by hand and it actually worked on the first try.
One area that we didn’t consider carefully enough were the human factors. Issues like gear-ratio, drive-train smoothness and prop-pitch were treated a bit haphazardly. If I were to do it again, I would put more emphasis on that.
If I’m not mistaken, rowing is more efficient than a propeller. There actually exist a hydrofoil rowing boat that achieves impressive speeds: http://pantheon.yale.edu/~jbm42/Hydrofoil.htm
But one of the drawbacks is that you can’t continuously drive the thing when rowing, so it drops down a bit into the water every stroke.
Carbon fiber,titanium are expensive and not available in many places. Foam and PCV pipe one can get most anyplace. a low seat height is recommended. A large pedal sprocket with a derailer. A small transmission, one can have a single shaft to a prop or create a dual ducted fan with high rpm . The hydrofoil wings can be wood or fibergass covered foam,much like a kit plane. Attached to vertical aerodynamic stansions and connected inside the foam float All frame work should be connected as the floats are there so it won’t sink. Sound like a red neck thing? Hell even sometimes they get it right.