Autonomous Solar Powered Hydrofoil: Part 1 

It shall be tried....

@@thinkflight if you also start to sing on your channel i will loose my shiat! nah seriously how do you have only 28k subs? half million end of this year. get it done chop chop! awesome stuff🤛

@@thinkflight what if you left the foils on and gave it some more juice?

@@thercproject9309 the same thing that was happening will happen again. just a bit more adverse

It seems like GE and hydrofoils could be complementary. I am guessing that with less load on the foils the tendency to ventilate/cavitate would decrease, so the GE would increase with the speed which would partially unload the foils.

Yeah hand made stuff probably won't cut it here darn it

3d printing, fiberglassing and vacuuming could work, it kinda did for rctestflight

@@thinkflight I guess you will need to diy/buy a 3D Printer, and CNC Router/Mill then... Sure would be tragic...

Jokes aside that is an option, but as Shingo Shōji pointed out, and you did at 11:18 I think various composites methods, as well as just making the scale slightly larger should work, right?

Also just pure determination / us collectively crossing our fingers for ya?

I appreciate that!

You should!

Its just that dang seaweed.... lol

That is quite an interesting suggestion on going to supercavitating foils. Hmmmm......

@@thinkflight Worth a try!

Fences were tried, but the rest remains to be tried. The next version will be swappable for submerged propulsion if the air props won't cut it.

I second the steep piercing foils! Trade off some, not all of the self correcting for better ventilation protection

Haha somebody finally noticed! 😅

Thank you for this comment. After adding more power yesterday and seeing its behavior I decided I wanted to steepen the dihedral angle and see what happens so I'm glad you are suggesting along those lines. By breach angle do you mean AOA at the water/air interface? When I go the molding route I will definitely blend out those nasty bends.

@@thinkflight breach angle is basically dihedral. I’ve found the more perpendicular the interface between the water and wing, the less likely ventilation is to occur. A few other things you could play with are washout and an adjustable stabilizer. Washout could decrease the difference in angle between the wings and stabilizer as height increases. This should move the center of pressure back and help unload the front wing and self regulate height. Small changes in size and angle can make a huge difference. I generally tune in half, degree increments. An adjustable stabilizer could be made from thin aluminum and allow you to tune the set angle by bending it. In surfing hydrofoils getting the stabilizer size and trim right is critical in achieving an easy and controlled ride. Hope this helps, I’ve been wanting to make something like this as an towed or rc fpv camera rig.

@@kanedewilde I found yesterday that a steeper angle eliminated my problem by 99%. Went from 22deg to about 50deg at the surface. I was also thinking of washout, so I am glad to hear you validate that. At double the scale I should also be able to hotwire these foils instead of hand shape, so I think these changes will do the trick. Will also think on a precise drag free way to adjust stab angle.

@@thinkflight that’s awesome to hear! Excited to see the video 🤙🏼

Thats awesome!

I was just considering this the other day!

It can, gotta set a trotting pace and not a sprint!

I do, send me one haha :)

Its usually on the lifting portion where the ventilating starts.

@@thinkflight forgive me for not making myself clear. The vertical supports that mount the foils to the hull are 90 degrees to the surface of the water, if instead the supports were, say 45 degrees to the surface, so they have the appearance of being negatively swept. Surely the air won't be able to creep down the supports cos at speed the water would climb up the supports. (Good lord, i don't know why this is so difficult to express.. i hope I'm making myself clear)

Thanks for the tip!

Will do

I'm not sure if "canting" is the right word, i can't speak english very well, maybe "swooping" ins a better term for what i am trying to say

Yeah, its a thing.... Not dead set on passive at all, mulling all possibilities.

Yeah it would help a lot when you would share that with us

Sure! www.amazon.com/Aircraft-Basic-Science-Eighth-Michael/dp/0071799176

@@thinkflight Thank you!

On hydrofoils those are called fences. I did try that on these, no luck😒

Agree, pretty much every outboard motor leg has cavitation plates for the same reason. Plus they can look cool like on old MIGs

@@thinkflight I guess the fences/anti cavitation plates don't scale down that small well. The smallest ones I've seen are at least an inch out from the foil or outboard motor leg which would be much more area than the actual foil. :-(

That would be cool!

Yes, absolutely

I'd love to know how you glassed the cells. I will definitely share all the electronics when all the bumps are worked out, they just weren't too relevant to this video but it's coming.

​@@thinkflight Original reply got deleted for some reason, thank God or a nerd for CTRL C... The process is pretty simple and would work for your application if you cut your deck from foam and eliminate that bump, or move it to the bottom of the deck. After you've hot wired your deck (assuming airfoil shape), you use the top negative side of the foam core to assemble your solar cell array upside down over parchment paper. Tape the cells together upside down over the negative core as they would sit on you deck. Solder them all together and ensure they're positioned appropriately. Shoot the back side of the cells with super 77 and let sit for a minute. Place the bare foam deck in the negative core, allowing the super 77 on the cells to adhere to the foam deck for a couple minutes. Carefully flip everything over and remove the core, you should have the cells stuck to your deck. Remove the parchment paper and put the deck with the cells in a vacuum bag sitting on the lower negative side of the deck core. I like to cover the cells with mylar to help press the cells into the foam. After 12 hours, pull the deck. The super 77 should be dry and all of the cells should be stuck down flush into the foam deck. From here, you simply glass and vacuum bag the deck as you would any composite wing with a few exceptions. Lay some carbon on the leading edge of the deck for bump resistance but make sure not to cover the cells. The bottom deck surface can use whatever cloth and saturation level you want. The top deck surface over the cells requires 2 layers of bias 45° 3/4oz cloth with minimal saturation. Apply your mylars over the top and bottom surfaces, apply breather (paper towel), sandwich everything in your negative cores, and toss it all in the vacuum bag for 24 hours. Viola! you should have a super sturdy deck section that's waterproof. Obviously during all of this, you'll want to account for wire routing. I just run the tabbing out to the root ends. It's also really easy to dremel away any glass to gain access to tabbing under the glass surface if necessary. Hope that helps. If this is all crazy talk, you can email me Chris@enopto.com, I'd be happy to help yah out. Been meaning to make some serious videos with this but life, work, and motorcycle builds get in the way.

My buddy can mold some foils so I will probably go that route, if he wasn't available I'd be open to other options. This doesn't need to be that aerodynamic, if the film gets into the gaps in between cells I won't cry so I appreciate your suggestion a lot actually.

If you can go thin enough, glass can be safely curved....and with proper heat treatment it will hold that curve.

I would be leery of going at these with a dremel but if I had a laser cutter I would totally section the cells. Key advice on covering with film, much gratitude.

No, the AOA wasn't equally set between the foils. Just bad craftsmanship :)

Probably, but I don't know for sure yet.

Supposedly yes, right now it has a few degrees of forward sweep. Further tests indicate a steeper dihedral angle at the location of breach is very helpful and is probably the root problem.

I forget which RCTestFlight video it was but one of his solar plane videos has a straightforward diagram on it.

Maybe an added bonus for having air propellers drawing/pushing air over the panels.

Tried that, made it worse.

Naaaahhhh :)

You would have no altitude control at that point, so you would need active surfaces. That is the main advantage of the surface piercers, they control your altitude automatically.

Yep!

Just put the motor in the water?

@@thinkflight I've seen people do that! I really wonder how long they last though. Especially in salt water.

@@eckern0 in fresh water they actually work better, so long as proper bearing lubrication is maintained. (Better cooling) Can't speak to saltwater.

Probably, this was a one step attempt that didn't work out so well. A two step process may give better results if I can find a dust free place for it to cure.

dunno, probably water

It didn't work great so I wouldn't bother copying it.

@@thinkflight because of the fiber glass and epoxy blocking the solar cells ?

@@srinathreddy2032 The finish was terrible and probably hurt performance.

I went back and forth trying to decide.... Still considering direction on bigger vessel.

That is one trick. I think I found the main culprit right after posting this video, we'll see how that pans out.

It is....

I don't know actually! You sure are thinking like a scientist though

@@thinkflight Or, perhaps, a single strand of "hair" from the lowest point on the wing on a floater. Allowing the air pocket to escape upwards. Either way, cool AF project!

You wouldn't believe how much effort went into making it as good as it is lol. It is frustrating....

@Think Flight still a great video...maybe get a lapel mic..

@@bukscoetzer This one sounds better tho

Kiteboards usually (always?) ride submerged foils instead of the surface piercing foils, which helps. And yes, the scale is also another factor. But as you can see the rear foil on this is a submerged foil, and it never ventilates either and was made the same way as the front foils that keep ventilating.

@@thinkflight what’s the principle/ goal of keeping the front foils surface piercing then?

@@rohansully584 Automatic roll and ride height stabilization in all conditions/speeds. So mechanically simpler, less to go wrong. IF you get them working that is....

@@thinkflight The trailing foil being stable might suggest there may be some quality of vorticity from the leading foil that could be possibly useful. Might be interesting to see if strakes or leading edge extensions may have a use in this case. Perhaps a little dart protrusion on the front with stubby winglets as vortex generators might be a way to calm stability or stall/ventilation issues? (Might be other ways that work better, but trying to picture something that seems simple enough.)

or a paddle hydrofoil lol

Me too!

Depends a little on where you are located, but yeah reach out to my email and lets chat.

You do know that's the same guy he went up to visit in the second half of this video?

I appreciate your approach much more than when I started this project. Love the stabilization system on yours!

Hahahahah