running a laptop on a rc boat is crazy

This is absolutely AWESOME. This is Ripe for a DOE (Design of Experiments) Analysis

All engineers should be schooled like this one- to experience the disappointment and frustration of mechanics that repair and have to service the equipment they design.

My man is about to print 300 propellers

Imma need an option to orient the motor at 90 degrees so I can submit a cyclorotor

This reminds me of Pinewood Derby. Someone will nail it by studying the test vehicle and getting the number right for the prop by optimizing for the test vehicle.

you really should name this red catamaran 'Mystique', in honor of all the faces it had since it was made.

Back in the early 70's I had a 13' Boston Whaler with a 40hp Johnson. In those days you had a limited choice of aluminum props and pitches. With the never ending search for performance and speed, this company (Columbian) came out with this "variable pitch" plastic prop. They were available in different colors, I remember having some red and blue. They were also advertised to be unbreakable (the company should have contacted me for testing first). They were constructed out of Lexan with a bronze hub. The pitch would "flatten out" under acceleration to help get on plane. This helped when towing skiers or to get going with like 4 people on board. Once on plane, you could back off on the throttle to more of a cruise speed and save gas (even though gas was cheap back then). The problem was that after some time, the Lexan would fatigue from all the flexing and a blade would snap off. Of course you would have to limp back home real slow because of the vibration. After running and breaking like 3 of these lexan props, I went back to the aluminum style. There's actually a NOS red one for sale on ebay now. This concept for a boat propeller has some advantages, finding the proper material is going to be the challenge

That laptop on the boat was terrifying hahaha

Every week or so I get this weird urge to watch an rc TestFlight video, then I go to his profile and boom new video

Thrust (in Newtons) * speed (in m/s) is a measure of the power delivered by the prop to the boat. So if you have thrust, and speed through the water, you can calculate prop power that way. Prop efficiency is (prop power) / (shaft power). I think 50 percent efficiency means you are doing pretty well. You can estimate the motor power output using torque (as estimated by VESC) and rotational speed.

I was stunned when I saw a laptop on that boat! Amazing work mad, I love it!

I'm not interested in propellers at all but I've been watching for 20 minutes, I like your videos. Just the right level of nerdiness😂❤

Now I want to see also drone propellers competition as well if we have PC fans and boat propellers already :)

Would be fun to see a variable pitch prop like you see on aircraft

Good stuff! But you really want to think of pitch the same way you think of thread pitch on a bolt. The pitch is the distance the propeller would advance through the fluid (with no "slip"). And this gives you the nominal blade twist automatically. You can then refine the twist with small changes to optimize the span loading. You typically want to unload the tips somewhat.

This is such a good idea!

This is going to be a fun one to watch. For anyone else who feels the same you might also enjoy the fan showdown. Similar concept different channel. Can’t wait to see this.

so glad to see you now using ELRS!!!

This is awesome! Time to dust off my Ansys and do some simulations...

It is amazing to see how your projects just grow and grow. You sir, are an inspiration to us all.

This will be a good competition, hope you get some great entries. So cool! 👍💪✌

I just wanted to say i love these watercraft videos. Especially the manned full size expeditions!

Dude...putting your laptop on the boat was insane!! You madman! lol

Thanks!

"The 1930 Robertson Waterplane ground-effect vehicle powered by an outboard motor". There are pictures and videos, but I don't think I can post a pic in the comments. I saw this the other day and immediately thought this might be something you'd build or at least be interested in knowing existed, if you don't already. In other news... it's getting to be grass cutting season. I hope you are working on your next autonomous mower contraption. I'm a long time subscriber to the channel and grateful for your willingness to share your talents with the world. Keep up the great work! - Stanford

This channel rules so much. Awesome content!

Thanks, man. Better yet, Amazon should thank you. Your vids inspired me to spend a few hund-o's on RC stuff... so far.

Looking forward to seeing the next part of this contest.

you could have just shifted the voltage up slightly with a voltage divider -- just two resistors.

This series is going to be absolutely amazing, hopefully it can be visited a few times a year.

Yeah! See you at Open Sauce!

Hey, this reminds me of the fan showdown series. Neat!

This stuff has always interested me ever since i got my own boat to maximise fuel efficiency. The real key for efficiency is prop pitch a bit of the design but most importantly is the cross section profile of the blade itself like an airplane wing to generate lift but on a prop you are trying to minimise friction as most of your thrust and economy loss comes from vortices generated by the tips of the blades as heat

Awesome way to control the parameters in your experiment! Very impressive!!

Props (proper respect) for an excellent video.

GOD YES ive been waiting for someone to do this sort of video

Excited to see the results!

Awesome! Gives me pc fan showdown vibes, cant wait to see how the series progresses

This is really cool! Looking forward to see what horrors people submit!

Did something like this with an ultralight propeller, drew the tip circle as a vertical line, set the rpm (IC motor with 2.36 reduction giving 2650 max rpm at propeller) and worked out helical path at desired 60mph cruise. This gave the ideal tip angle, discovered reducing diameter allowed positive pitch angle of attack, as diameter increased it began to go negative. Research showed aero profile still give thrust, even if aircraft velocity and prop rpm resulted in negative, up to about 2 degrees. Your work is brilliant.

0:58 yeah it’s sweet using multi material. I use PLA as support for PETG and the undersides are Lush.

props for your efforts!

the best use of the prusa XL I seen so far

You also should calculate the optimal hull speed for your catamaran, since it works in displacement mode. And after that test the props for that speed.

Nice video (and competition). I was wondering about the drag on the surfaces themselves, which also adds to a loss in efficiency. What would happen if you would change the surface structure of the blades and cone to very smooth instead of the rough surfaces that come out of the 3D printer? Or even better: make the smooth and very hydrophobic with an additional coating? I'm aware of the fact that this no guarantee for lower drag, because for example golf balls are purposely dented to achieve better aerodynamics. But maybe this is an aspect that you (ar a contestant) would find interesting to look into.

I took an almost identical approach trying to design a propellor for my electric outboard motor for my sailing dinghy. It's super interesting seeing how sensitive the diameter to pitch relationship is. I was also trying to find an optimal propellor for recharging my battery when under sail.

You need to revisit the diameter, after discovering how-wrong the pitch was, on your 1st batch.. This is part of the principle of looping back *far enough* in the design-cycle, for what one's project is actually doing.. ( Wysocki's book on project management, Extreme & Emertxe projects loop back to "should this project continue?", Agile projects loop back to "What is the next deficit that we remove?", Traditional projects loop back to "what is the next item already-decided that we do?" Research is extreme/emertxe category. )

If you circulate water in a loop you can get dynamic thrust data indoors 🙌 and I bet you could tune the loop to match drag from a boat..... although actually please keep lake testing it's more fun to watch 😉

Most excellent.

Awesome project!

Looking forward to see more of that radar prototype thing in the future. The small/mid scale USV market desperately needs that.

Wow, great work!

Keep up the great work!

how easy those supports come off is so satisfying

Daniel, often times, the power efficiency in an electric set-up is dependent on how well paired a load is with a motor, and where you are in the efficiency curve of the motor. Have you considered measuring watts as Torque * RPM, rather than V*I going to the motor, in order to exclude any efficiency variation in the motor?

thanks for this great video! im so inspired, and its also VERY great for PCB way, they can produce very nice components!!

If you want to run numerical analysis but don't have acces to cfd and a large amount of compute, an alternate approach is using blade element momentum theory. I used a python implementation, PyBEMT to optimize a propeller for my BSc. Thesis and it worked really nicely.

Looks like you equipped your boat with an SPS-48 radar set. Nice touch!

What brilliant idea for fun competition, there way smart people than me that hopefully come up with some great designs ? I like ask few questions ? 1) all our designs limited to 3 blade like yours were ? 2) What about surface drive props that may be better at high speed ? can you change the depth they run at ? 3) Could someone make variable pitch prop ? not sure if you could design passive system at this scale Am really Looking forward to the results video in few months love jenifer xxxx

that ESP32-testing rig is very elegant!

Definitely going to be a lot more than 20.

0:50 Lol- Love the ‘paddle’ getting *ornithopter* vibes :o

0:05 I've had so much fun too!

AWWW YESSSS!! I already submitted a design.

Amazing!

LET'S GOOOOO MORE AWESOME POSTS

Didn't know that about petg and pla not sticking to each other as tediously. Interesting!

Wow, excellent video! Maybe a good way to measure current would be with an induction amp meter, used commonly in a lot of multi-meter style tools? Excellent to see Airshaper in the video, who I highly recommend to anybody looking for efficient CFD studies. Their website is full of interesting studies, detailed in extensive PDFs. In case anyone is wondering about the Onshape propeller template, it is also meant to work with the book of HAVF airfoil vectors I published. So, the onshape model is capable of swapping airfoil very easy, from the currently used ones, to any of 1500+ other popular airfoils. That's part of the reason Daniel is able to change the trailing edge so easily. Airfoil vectors are the future, ditch those DAT coordinate files!!! Now.... to start on my submission.

Good job.

i would HIGHLY recommend looking into multivariate experimental design! there is a video by nighthawkinlight that explains the basics. as destin also mentioned in his comment about DOE this would be a great situation to do some really cool experimental design and data analysis!

This is a good way to promote technological advancements in propeller design.

The little radar is the icing on the cake 🎂

Wait, you strapped a laptop to a RC boat? You're madman! I'm trying to think up the reasons you can't do that!

Subscribed to Fan Showdown for a year now, and as RC hobbies guy I am much more interested in competitions like that o) And that is where I might even try to submit something despite being a software developer o)

yes a new video its everytime so fun to watch

laptop on the boat had me crying XDXD

That weird patch of water was probably some kind of thermal inversion, or there's an outflow pipe dumping storm water out there.

Hell yes!

Would recommend trying out configurations in onshape for this sort of thing. They work really well for switching between models while changing a bunch of dimensions and are much easier to set up than I expected.

I'm telling the naval architecture students at my college about this. Hold on to your britches

watched the fan showdown series by major hardware, see this video, screams with joy

Sending a wish out into the ether for a prop in the 800 to 1500w range that could power a mini catamaran powered by solar. I truly think something like that paired with modular catamaran hulls would be a commercial success for various applications. Love your videos.

Oh what a difference the pitch makes. Twenty four tiny degrees

In your Onshape CAD, the intersections are faulty. Thanks for leaving it public. 👍

Awesome video, but I wish the RCTestFlight channel would get back to planes some day :)

Another thing to consider for efficiency is rudder location. Offsetting it would reduce drag since the prop wash is effectively moving faster than the surrounding water. Then again it would potentially reduce it's ability to turn the boat for the same reason. Better yet you could make the motor pylon itself rotate. Outboards and tug thrusters are obvious examples.

This is similar to fan showdown where you can design 120mm fans. Love it

This is great...

I love this I love this

Hi, i dont know if it has already been taken into account, but for a better propeller i think you should take into account also the weight of the vessel, the "hydrodynamic drag" of what you are trying to push/pull, and the result will also change for the cleanness of the waterflow, the best is the pulling propeller layout, if i'm not wrong. Don't know if someone already pointed them out, hope this is useful.

Oh heck yeah. Do I know what i’m doing? No. Will I try anyways? You bet 😂

Submitted my "design"! Hope you roll with it ^-^

great idea, but I have no clue about propellers. But I have a 3d printer bought on black friday from bambu - but still unboxed cause too much going on that needs to be fixed first before I will have time to play around with that x1 or however it is called.

This is so cool. I always look forward to your uploads. I wonder if a toroidal propeller would work in a jetpump? If it is even possible? It would have to be flat at the top to get a good seal with the pump liner. Hmm. I have seen Toroidal Propeller in a fan Duct so it could be possible. What do you think?

In full-scale boating, the diameter and pitch of a propeller is the equivalent of a transmission's gearing in a car. Absolutely critical

So cool

game on !!!!!!

After watching this video (and the linked conversation) I got an ad on another social media platform that showed a close up image of the market’s leading toroidal propeller. Note: It doesn’t have a tapered cone on the trailing edge. It has an open cup with small fins inside. I wonder if the open cup on the trailing edge of their propeller adds efficiency by giving the bits of cavitation on the prop surface a centralized negative pressure space to propagate them into an organized column that can allow for more efficient flow? I haven’t spent any time using computer modeling so someone else will have to test the theory. I hope you find one that suits your needs

Varying only one variable may not be what you want to do. It may happen that the pitch and diameter are both need to be changed. Vary rarely the geometric variables are uncorrelated in fluid dynamics. I would suggest to print multiple variants where all variables are changed. Diameter, pitch, thickness, the size of trailing edge serrations. Then you can use something like linear or logistic regression to fit the efficiency data using those variables, then you can use the fitted function to find the global minimum.