Testing 8 Innovative New Boat Propeller Designs
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- Опубліковано 13 тра 2024
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I like how you absolutely shat on the guy with his 'patent pending' prop and absurdly high confidence, and then immediately proved your point. Insane how people just refuse to take feedback
Yeah, I don't wanna be mean to the guy, but I really don't see how the curved rectangles on the tips could be anywhere near optimal even for that design. I feel like they should be at least a little rounded in some way, right?
"9/10 chance of winning"
*literally got beaten by every other submission this episode*
gg, nenad.
@@mitchib1440 Perhaps he thought the chart was reversed, 9/10 chance of loosing? :)
Though I do wonder how that prop would have worked with more power and higher RPMs (assuming it survives that)
Time to short
That under water footage is amazing, props for taking this much time to create a video.
Pun intended...? :D
@@apacheandyyou beat me to it
I nearly clicked away and had to come back. Wonderful pun, bravo.
props, haha
props 😎
“So cool.” Little old Asian man was just genuinely interested in what you where doing and was probably bored, just out on a walk and I bet seeing what you where doing made his day and gave him something to talk about. Awesome how being creative and interesting draws interest of strangers, I don’t know why more UA-camrs don’t do public shows or lectures and stuff.
Wrong.
Was a Spai.
@@evanray8413came here to say the same thing lol. That’s probably my military training and bias’s
@Juddly05
I'm just a skeptic.
No training at all. 🤪
*_As a long time RC boat enthusiasts you get people come to watch no matter if it's raining cats and dogs outside and the questions never end._*
Never can appreciate enough the j-cut from " oh I needed to design a custom mounting arm and foil for the slow mo camera capture" and YT pov is like 3 seconds, while who knows how long it took to implement.
"Props" to you good sir!!!!!!!
So many creators drag us through every little side project painfully. I suppose it could still be interesting but there's a limit. I appreciate his judgement.
I love this format.
- Shit on the bad designs and mock submitter's overconfidence
- Test props
- Shit on the designs some more, but with data
"See. Look at the graph. I told you it would be bad."
And the huh... I guess it works, but why?
BAHAHAHHA this is gold
THOSE DUCKLINGS HATCHED THEY'RE FUZZBALLS
...yeah low reynolds number ain't shit if prop design is crap
And mock their underconfidence haha
I love how an interesting RC channel turned into a seriously scientific resource for water propulsion.
i predict that in 5 years we send a probe to europa
you missed the bit where this was not only and RC channel but an RC aeroplane channel lol.
Honestly it feels like he saw how successful MajorHardwares user submitted PC Fan series was and said “hmm I can do this for propellers” either way I’m here for it
I am pleasantly surprised to find your channel and your testing. Always wondered what the best prop would be. Just fun to watch.
Right? I'm not even into RC stuff, at all, but I subscribed anyway. Fluid dynamics and homebrew engineering is more fun than it seems it would be.
why do i keep watching these videos? I hate water, i dont care about boats, propellers ive never even thought of in my life YET im here for every damn video and i love em all!
Curious isn't it. I'm similar. He obviously has a serious knack at making things we are NOT interested in interesting.....
Who TF hates water? lol
@@Johnnywhamowater is generally always too damn cold and when it comes to low temperatures im a wimpy bitch xD
I love how a video pops up on your feed, so you give a quick watch just to see whats going down. Then a half hour in (due to multiple intermissions, thanks wife) you find yourself subscribing and searching for the remainder of the tests.
Great video, from the narration, to the cinematic views. The work and time you put into making this view is top notch.
I love this sponsor integration. You actually use it for the video and don't just cut back to the shop to tell me about incogni
When you started this I thought it would be more like the fan showdown, but honestly the amount of work you put in to make it both scientific and interesting is just amazing! The footage looks great, and the bubbles really make a big difference when trying to understand/explain the performance!
Fan showdown wishes it could be this good.
At least the fan showdown guy is not shitting on people with his superior opinions and it's just for fun
@@infernus6278 I feel like he was very objective. The results don't lie and aren't just opinions! And I feel like the prop you are probably referring to was given a fair chance, he even told him the angle of attack seemed too low beforehand! Also you gotta keep in mind how many different props (but also wings, hulls, etc) he has created himself, I love that he has some insight and gives a little hypothesis
I was also thinking fan showdown (Major Hardware) or Project Farm
@@jaspervandenameele4834 im not talking about that last objectively shit design, the whole vibe of the episode is wrong
Wow my design is actually in the lead so far! Be interesting to see what surpasses it.
Those 'stagnation points' behind the hub are partly because of the hub vortex. I actually designed a v2 of my prop with a simple hub vortex diffuser to mitigate the associated losses, but in the video it looks like the hub vortex of my design is already pretty weak so it might not make much difference. Definitely worth trying on a smaller diameter prop however.
That weak hub vortex caught my eye, indicating the blades are operating at a very good lift to drag ratio. Nice design job.
@danedmiston9673 thanks!
What if you added dimples like on a golf ball.
@@FogGoblin Golf ball dimples are a kind of turbulator, you should go read up on how those work (it would take a bit long to write it all up here). Basically they're pretty situational, and only help when the flow is laminar and speeds are fairly low. Under other circumstances they actually increase drag.
Boat propellers usually have various stuff (like the skeg and bubble generator) upstream of them that messes up the laminar flow into the blades anyway, so there's probably not much point using turbulators. Also this prop is spinning fast enough that it is mostly outside the range of speeds where they'd be useful.
@@nerd1000ify Thank you for reply. Last comment, what if someone printed a Prop that was more like a Driveshaft and have gears that are pushed by boat moving. Or why cannot you add a prop in front and in rear? I lack intelligence but I can beat you all in imagination.
You know what I love? I used to watch you chuck foam planes out your window and now you're doing boat prop tests. Keep fing going, I love this stuff 💪🏻💪🏻💪🏻
12:11 I love how you can see another prop he seems to have dropped hahahaha
lol good spot
hope he picked it up haha
Prop 43 is sitting on the bottom
Actually 12:07
It explains better what you were referring to.
@@derjoh1986 actually they were talking about a second fallen prop that's visible right before the cutoff.
We need more like this. Maybe do a hull design version. Set the common level using displacement and let them go wild
Making crowd resourced hulls is a lot of work and filament😀
@@vitsalava1251 I thought he did a video about hull design. Not a competition, but a video about it.
I was so happy to hear that you ran multiple tests per model. Sometimes I see people doing tests with a single execution in situations with thousands of variables. It's ridiculous when they do that, it invalidates the entire test.
That bubble generator you added is amazing. You can learn so much by being able to observe the effects like that.
Overlaping efficiency graphs with the same scale would be nice so we can visualy compare them, otherwise they all look the same
This is like The Bachelor for nerds. I for one can't wait to find out which prop the boat ends up with!
and the rose goes to the simpler is better
😮 Im a nerd now..
Pc fan design is another one that can get this crazy imo
@@extremechimpout I mean, we're watching a competition about boat propeller efficiency - so I mean, _we are what we are._ Might as well own it. Don't get me wrong. I don't mean it in a derogatory way, quite the opposite.
Lol, very apt description.
22:30 I love that random encounter with a guy just asking what you're doing and then getting really interested as soon as he understands what's going on.
23:12 SLS prints are far more porous than even FDM, so the air might be coming from inside the prop, the wax should seal it relatively well but maybe the wax coating wasn't even/thick enough to seal it everywhere.
I'm an industrial designer and at my company we ran into that issue with a vacuum suction cup system, the SLS part could barely hold maybe a third of the vacuum we were aiming for.
8:28 really loving the makers community embracing a more interactive YT experience with all the testing of entries.
I love how you blitz through the narration. It's like you are explaining complicated, cool stuff to a friend.
Damn dude you really are alive at your perfect time. Can you imagine trying to have this channel without a 3D printer?
As a retired Naval Architect I thought your experimental approach was brilliant - really enjoyed it! kind regards John
I absolutely love your channel. I love how casual you are about the most amazing stuff like the "bubbler". The quality of the underwater shots is amazing. Also, I love the turtle at the end. Please never stop making videos, you are awesome
I am not, by any means, as scientific as the majority of your viewers, but I really enjoy your channel and the testing you are doing.
buddy, none of us are all thst technical. lol
Not true! Some of the viewers here are technical, and some are even experts in the field of fluid mechanics. This channel is great because it’s interesting and informative for many types of viewers. It’s awesome and cool a fun stuff!
@@pejoka nope. i call bullshit. we dumb; dumb as hell.
I'm an old timer and physics major and congratulate you for such a professional presentation and quest! Best of luck!
The spiral bubble path you were concerned about on the baseline model are caused by the rotation of the propeller. It is not cavitation. The propeller is generating a rotational force as well as thrust. This rotation causes everything it acts on to try to move outward. So air bubbles hitting the blade are being pushed toward the blade tip by centrifugal force and leaves a trail of bubbles along the blade path. Some propellers try to use this wasted energy by using a ring or nozzle around the blade to redirect the water to the back. A prop similar to the ring glide with the proper attack angle and 3 blades would perform much better. As for the Fibonacci propeller, its design is not suitable for high speed. It will likely out-perform all the others for precise thrust control, especially at low speeds so it’s not a useless design, but for a different speciality. Adding a slightly bell profile to the Fibonacci blade should serve to increase the thrust it provides and allow it to compete more effectively in your test.
The most impressive thing here is the camera set up that allows the props to be filmed in-situ!
Now you need to graph author confidence level against efficiency results!
I predict an inverse correlation
to make it proper and show how the water reacts or goes in every prop used just by putting bubbles thru the path is totaly genius bro, i love the way you think and surely i love this video
Theoretically, shrouded propellers are way more efficient than any open prop (30% plus). We did this work on an Exxon project decades ago. along with several torpedo jobs. Also for submarines for low-noise service in hostile waters. This also applies to airplanes. The shroud also allows higher pressures through the turbine, as opposed to the free-air or free-water edges, since the shroud can direct the excess off-axis flow, out of the back. Any open prop is limited to cavitation limits, as based on the water pressure, thus cannot force more flow (F=ma) than allowed by the medium. This also applies to vacuum cleaners and airplane props. In water the shrouded props have a bad problem of fouling from debris, ropes, weeds, etc, thus open props are better used for contaminated situations. There are designs where rejection of debris is the most important variable. You should do some videos about the fouling issues.
Wageningen is a place in the Netherlands. Kinda sounds like Wah Guh Ning Uhn (accept the G in Guh is more like a soft version of the CH in loch)
MARITIME RESEARCH INSTITUTE NETHERLANDS is located in Wageningen.
Wagon ninja?
@@Alex-zi1nb close enough!
Aerospace engineer, i can say that the wing vortex isn’t actually localized to the wing tip, it’s distributed across the length, just often is so concentrated that it appears as a single vortex at the tip. The long prop might simply be very elliptical in its distribution (i e efficient vortex minimization)
I think I have seen several other studies where longer length is thought to be more efficient, which is helpful for solar powered systems.
@@vahnlewis9749 certainly, the longer the wing the more of it behaves like the infinite 2D wing which is almost always far more efficient. The traditional theory is that vortex related drag (proportional to lift squared, thrust in this context) scales inversely with the oswald efficiency (wing/prop design) and inversely to pi * the aspect ratio
@@youngbloodbear9662 As an aerospace engineer, I would love to ask you a question about how airfoils work. I am a sailor by the way. There are two lifts on a wing, one is the Bernoulli, and the other is sometimes called Newton. Bernoulli suggest the lift on a wing relates to a vacuum produce above the wing due to the separation produced by the wing shape. The Newton force is the force of the wind pushing on the underside of the wing. I think both of these are involved in lift, but I think in many cases the Newton force is larger than the Bernoulli. Is there any reference that describes the magnitude of these two forces on wing addressing the factors of foil speed and foil angle?
@@vahnlewis9749 i don’t have a good paper to reference off the top of my head, but I can say very confidently that in most cases, most of the time, the ‘newton’ lift is significantly more important than the ‘Bernoulli’ vacuum based lift. What is really critical though is the difference between the surfaces, breaking it into components is just semantics, its the net pressure differential that generates the force. Its also important to note that if newton lift was the only thing that mattered, wings wouldn’t stall in the way they do, if the bottom surface were the only part that mattered, we wouldn’t care if flow separated from the other side, but in reality you drop like a rock. Even if the vacuum isn’t as strong as many would imply, that steady low pressure flow is still necessary for the higher pressure on the bottom to push against, because it isn’t *that* strong either. A good example is a big heavy fighter jet might have a wing loading of around 80 pounds per square foot of wing, thats only half a PSI total on average in level flight, and thats newton and bernoulli combined… even pulling maximum G’s that’s only 1/3 of an atmosphere difference in pressure. The reality though is that these simple breakdowns of newton vs bernoulli aren’t capturing the full picture. If you take a step back and look at the effect on the airflow, treat the wing as a black box, what you need to see is how much momentum is being imparted into the flow, and that force has to be reflected in the wing, basically just an abstraction of newton. When you do this, it turns out that you can back out a parameter called circulation which is equal to the lift. The more the wing causes the air to curve around it and change direction, the more force it generates, and thats due to both pushing from the bottom surface and from the suction over the top. This doesn’t factor more complex interactions with viscous flow and vortices etc but thats the gist. One last caveat is for highly supersonic objects, newtonian flow is almost perfectly accurate, the more supersonic the less these ideas of suction have time to really take any effect
@@vahnlewis9749 Lift is created by the difference of the pressures under and above the wing. It involves both vacuum above the wing and excessive pressure below the wing. But vacuum can have around 3 times more deviation from atmospheric pressure than excessive pressure below the wing, so the most of the lift is created by that vacuum.
Maybe i didn't wrote it clear, English is not my native. So here is formula of what i meant: P_above - P_atmospheric ≈ - 3 * (P_below - P_atmospheric)
It is important to understand that without pressure below the wing, there wouldn't be any lift so both create it and both are used in Bernoulli lift. And Newton lift is just excessive pressure below the wing which is included in Bernoulli lift
Propellers aside it is neat watching your test platform evolve. That little catamaran is cool.
13:04 bless you
Crazy I was going to comment that’s if you hadn’t 😂
why?
what's at 13:04?
Used to work pit crew for outboard hydro racing. The props were stainless, with 2 blades, running the hub partially submerged. Boat speeds varied depending on engine displacement, but 120mph with a 40 cubic inch engine were common. We noticed the higher the rooster tail, the slower the boat. The 60 cubic inch engines were throwing out grapefruit size water "chunks" at no more than 6 to 8 feet high. The winning prop would have worked great, but 300 horsepower required thicker blades.
When I use to race hydroplanes new guys would try the hydrophobic stuff all the time, things used on sail boats and such. And they often worked well at lower speeds, but at higher speeds they actually caused more drag, sticking the boat to the water (hydroplanes run the fastest when they use air pressure under them to lift the majority of the boat off the water).
you my friend are an engineer showing his worth, I appreciate your transparency and gratitude for the designers, keep up the good work
OMG another rctestflight video! this quickly???
Googling the paunovic props, it really seems like they're intended for drones where they're able to spin much much faster than boat propellers usually do. So it seems like an odd choice to submit it for this contest, especially without changing it in any way for the lower rpms
Yeah. It's clear he didn't check rpms or only tested it for static thrust. Interesting idea, just not optimized for situation.
Kinda hard to imagine why such a supposedly “brilliant “ designer would miss the obvious scaling issue so badly.
16:18 Came for the propellors, stayed for the nature videography
Amazing that you come up with details like the idea of air bubble injector. Also, this is video is very useful because I'm building a simple catamaran that can carry a large magnet for magnet fishing, so I don't need to mess with propeller testing.
watch techingredients video about electric catamaran propeller. he did the testing and arrived at a 3 blade ccw pusher prop being the way to go I believe. i kept hoping one of the designs was going to be similar to that but none were:\
@@tylerlaird91yet...
@@jumpsneak 😄
This is some of the most visually stunning science ever captured.
Was bored, Decided to click on this video, Honestly surprised at how detailed you are and informational this all is. You are geeking out on something so obscure the same way I geek out on juggling toys. I love it man!
As soon as i saw your map of the test run i recognized the docks of the hydroplane pit area! I was just there last month testing out some paddleboard motor fin designs!
Epic video and sneeze, can't wait for the next one! So far it seems like more plastic == less efficient. By this metric, you should try the motor without a prop, it should be super amazing! :P
Awesome test session! Very scientific! Love it! This reminds me of the cub scouts "rocket derby" I attended back in the early 60's. The idea of that was for the "kid" to build his OWN rubber band powered "rocket" and run it along the taught fishing line at the meet (the big test day). I carved and painted my own rocket from the base line starter kit, and got a lesson on a few different things along the way. I didn't win the event but managed to come in above the middle of the pack. The winner's "rocket" was built by some kids dad that was obviously well skilled at model building (it was like something from NASA). "Dad" added graphite powder to the prop bearing surfaces and saturated the rubber band in like castor oil or some special liquid to reduce the unwinding friction. Like a 8 or 9 year old kid knows this stuff? Lol!
THAT BUBBLE GENERATOR IS GENIUS!!!
I built RC gas boats in the early 2000s. Never got the tuned brushcutter engine to work well with the (few) available props. 20 years later, and you are providing many of the answers I was looking for 😅Keep up the awesome work, you are my favorite youtube channel.
Amazing how much you've progressed since your earlier videos, I've been watching this channel for years. Great job, very enjoyable and well put together video.
Right!
Here before Elon hires him for a high-level position at SpaceX 🙋♂️
This is such a great video and idea in general - I can't wait to finish up my university studies and have more time to get making some similar projects! Great to see so many designs that I have covered in videos make it into this competition! 😀
I'm making this comment immediately after hearing about the hydrophobic coating.
My immediate thought is that would lead to more cavitation, because the hydrophobic coding repels water. I think you should test using a hydrophilic coating. My layman's hypothesis states that would have less drag over the surface of the propeller
Yes!!! I wondered the same thing! It would be nice to do a series of tests on different surface rough ness and on different wetting conditions.
First PC fans and now propeller designs. I love all this free R&D!
13:04 bless you bro😂
That is fantastic nerd content. There are not many creators that put so much efford in their videos. That must have taken weeks to setup. Really appreciate it.
I like the innovative thing this video has, I have nothing with boats _just water_ but i watched the whole thing with a smile. Thanks for sharing from Mexico
For finer bubbles, try using a couple of strands of wire and a power supply to split the water into hydrogen and oxygen. We used to do that in our water tunnel at work.
Wouldn't the fibonacci propeller be GREAT for avoiding seaweed snags? I think that sucker could run through a bass lake no problem where other propellers would get caught up in growth
Rounding the edge at the start of the vortex could help a lot by driving through seaweed too
19:20 coolest visual I've seen in a minute, like a ancient Japanese painting of the ocean.😎
It's so cool!
Looks like a Kelvin-Helmholtz instability. 😏 (I think I learned that from Veritasium ..)
As a marine mechanic, I love this kind of stuff. Can't help but think some kind of tank would have given you more control over things. Power over thrust would be cool, different pitch tests, variable rpms, this could be a career plan for you. Good educational content, this is what you tube is for. Thanks.
Awesome camera you got there! Smart idea with the probe lens I’m shocked at how well that light came through underwater.
RIP "Paunovic"
Hope the patent costs are worth it for you lmaooo
Let this be a lesson - don't get cocky.
Most patents are done in hopes of it being used somewhere else and owning rights
@@frankdobs But at least they should have even the slightest chance of being useful.
considering it was mentioned to be "quieter and more efficient than a regular drone propeller" im assuming this design was made with air in mind and not water. water really just is a different ballgame.
@@thegforce522 but it was submitted for a water challenge...
@@mitchib1440 yup, seems the submitter underestimated how vastly different water props are. it would also make more sense as to why the pitch was lower, and why the efficiency curve was going up. it is probably made for much higher rpm and lower torque applications.
love your vids because of you got in to engeneering
Don't know how this video made it to my algorithm, but I'm happy it did. Kudos to the effort spent with the underwater setup.
For that last prop without enough blade pitch, you said "the efficiency curve is opposite for some reason"
I think that because the prop was pitched too shallow at first, but also made flimsily enough that as you increased the power, the propeller flexed into a more and more efficient pitch.
I have a feeling that running compressible fluid simulations assuming completely rigid shape, and running it up to a few thousand RPM where you begin to see some compression of the fluid at the right locations, it may work well. Just not for low-speed applications in non-compressible fluid with a too-flexible material.
Great video! I subscribed because I've been wanting to know more about a handful of these propeller designs, and you did all the testing for us in a very scientific way, so thank you for taking the time to make this video! I can't wait for the next one
21:00 Likely this prop never reached its efficiency peak, while all other props always started past it. The full efficiency graph should be like a mountain, not a single slope
It clearly couldn't reach higher speeds, anyway you can see it almost at plateau in the end of the curve, and with the "corrected parameter" calculated at the apex it was still dead last
@@8paolo96 Well, it was so clear to me that i didnt think to even mention it
Remember they designed this prop for the 400 watt motor with a target speed aswell, if it didn't reach full efficiency then it was badly setup for this motor. All props regardless of style or design need to be correctly sized (diameter and pitch) for the motor driving them this is standard in the boating world.
Also given how badly the prop performed and the angle on the graph it should likely would never reach a efficiency remotely close to the other props, also note the design was intended for metal it should have been altered for plastic (knowing it was going to be printed) as it may not have broken but it may have been flexing altering the intended pitch angle and hurting the efficiency more.
The final nail in the coffin for this design really is the flow, the goal of a prop is to push water backwards any water moving in any other direction is a huge efficiency loss and those swirling vortexs moving at the outer edges of the blade looked to be around 20% of the blade lenght a huge section of the blade that was effectively fighting its ability to push water backwards
The propeller on that motor couldn’t reach higher speeds, so how does the efficiency past that point matter if it is unable to run at those speeds?
It did reach its efficiency peak for that motor.
@@DumbGoogle-yz9cr Resin is actually extremely inflexible, it will shatter with not much more bend than metal would. The fact it didn't break already tells it wasn't flexing, it was just so inefficient that it couldn't perform well enough to break itself.
You should try to sync a strobe light to one of the motor phases. Maybe an car ignition strobe light will do, they usually have battery connections by design.
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Before I watch the results (excuse the lack of terminology knowledge):
- Hydrophobic default: Just why?
- Twin Turnip: I think the shaped tip will do good to reduce eddies/vacuum.
- Spin Doctor: Genius design to maximize the surface area of the blades while maintaining a consistent angle without much protrusion. It also maximizes structural integrity and enables adding more blades for bigger propellers and motors. Though it seems to also increase the likelihood of things getting caught in it.
- Ring Glide Propeller: Terrible. Why create extra dead weight that reduces scooping from the side and increase drag?
- Bigger Diameter is Better: I imagine it depends on the motor? More energy required but stronger propulsion.
- Nodules and Feathers: Reinventing the golf ball. Which is to say it looks good.
- Painovic Propeller: Seeims like Spin Doctor but with sharper edges. I think it'd underperform Spin Doctor only because it's made to be built out of metal (so I imagine it'll get bent or break), and because you said part of it wasn't printed.
- Fibonacci Flippers: The blades seem to inhibit the other blades from scooping. The propulsion doesn't seem to be very straight. So many vortices. This might be the most terrible if the others don't break.
Thank you so much for testing the hydrophobic coating; it’s something I’d wondered about for a long time
Same with tubercles too omg
Your videos are so great. I’m studying maritime technology in Germany and you motivate me so much for more!
This amount of work for this vid is more than i did in all my years of school put together.
How the hell did you make it through? And I’m really curious as to how you’re doing these days… school sure isn’t a guarantee of success, or of making money.
I love the underwater video with bubbles!
Wageningen is approximately pronounced "wah-guh-ning-an", with primary emphasis on the 'wah' and secondary emphasis on the 'ning'. The 'guh' has a schwa and the 'an' is like the non-emphasized first part of 'an apple'.
Perhaps many entrants confuse aerodynamics with how fluid dynamics works in water? As water is not really compressible, while air is. In Aerodynamics compression, low and high pressure differences play a huge part. In water this is negligible compared to that.
If the airsped is below ~100 m/s you consider it incompressible as the effect is neglectable. The only real difference, apart from viscosity, is cavitation.
For that guy with the patent, the problem is somewhere else. Even for air, his propeller would be shit.
You can compare it a bit to airplanes. He built a bipline-equivalent. Biplanes only advantage is structural integrity. It is easier to build them more rigid. That's why they were mostly used early on when materials etc. were not so advanced.
The most efficient airplanes are gliders (yes, the concept of aspect ratio does apply to propellers).
If pressure differences would be negligible then cavitation would not be an issue, so your statement is invalid.
@@falcofranz5005 Well, happy to disagree. First, read my comment. I wrote, "negligible compared to that". I did not write "non existent".
And what I wrote is true. Water is not compressible, while air is hugely compressible. Completely different in this regard. Cavitation is a very special effect. It only happens at a very low pressure, and suddenly. It does not happen at high pressure. And it happens at a special case. In all the other pressures, and pressure differences it does not appear, and does not have any effect on the effectiveness of the propeller. Like 99% of the time. While air pressure differences affects the effectiveness of the propeller 100% of the time.
So it is truly negligible compared, and it can be handled very differently than other aerodynamic effects.
I think we both agree that the flow dynamics in air and water are very different, since water is incompressible and can undergo a phase change. Also the viscosity is different so the production and dissipation of turbulence is also different. Also the speed of sound is higher in water so shocks are unlikely to appear (cavitation will occure before that).
What we disagree on is the term „negligible“, which I think is wrong here, because cavitation is a phenomenon that indicates drastic pressure drops. And since cavitation is very lossy it is in my eyes a defining factor and not a negligible effect.
I hope this becomes a regular thing like the PC Fan showdown 😂
thinking the same thing, now i have to go check that out see if anything's new.
Stumbled into this video, but I am a lover of engineering, testings, collecting performance data. This was great.
This is a really cool demonstration of how so many variables need to be accounted for, in just 1 specific scenario. Can't wait to see the rest!
Very cool, and that onshape tip was nice, very handy CAD for hobbyist like myself
Wowee, what a well thought out test and enjoyable video. Can't wait for the next one.
Just realized how big of a nerd i am dammit
we nerds are more fun anyways ;)
Why?
@@denisivanov1140more knowladge. I like to be a nerd when it comes to stuff like this. Also made a underwater drone. Multiple times 😁
Wow. I've got no interest in propellers, but this is surely one of the best tests I've seen - of anything. Love it. And yes, now I'm one of your 708k followers.
Incredible work! Really loved the camera setup and bubbler, along with the method in which you gathered your data!
I noticed the "patent pending" blade completely changed shape under load. I think it would perform completely differently if it weren't so flimsy. Not necessarily *better,* but different.
If only I had noticed that previous video for this competition, I might of submitted something,
Although I really look forward to seeing how all these propellers compare!
This is an excellent demonstration in hydrodynamics. What works in the air won’t work in the water with a density increase in media. Air is ~830 times less dense than water
Lake house for cheap... good one.
Fuck, that sneeze was epic 😂😂😂 well done mate. Well done. Oh and get well soon lol 😂
I can't wait for the results, and then to see if it scales up, would LOVE to improve my small boat.
Wow! Great work! Awesome!
You did a great work! I'm waiting impatiently for the next video!
I think the paint will better than the bubbles.
should've tested out some sort of flexible active prop
8:53 every scientist just recoiled when all of the props are printed from the same material except one and it has a rougher surface.
Drives me crazy when people will change variables like that, now if it performs well or poorly, we won't know if it's because of the design or the material
Eh, it's really the geometry that will make the difference. The weight is probably close enough to be a very minor factor, and with the wax finish smoothing it out you can see how small the impact of a slightly rough surface is.
Maybe a rougher surface makes no difference at all. But otherwise think of shark skin, microscopic fish scales holding bubbles of water to reduce drag.
I really like your analysis methods, snarky commentary and explanation and the bubblefoil. It provides some interesting wet visuals to go along with the dry data.
(patent pending plastic paperweight - 9/10 - would look great on the captains desk, but only while at sea)
So much effort man! But it pays off with such a cool video for the whole world to see and learn! Thank you from Warsaw, Poland!!
You are on your way to greatness, Mr. rctestflight! Such a well planned test setup; it was a hypnotic joy to watch. Can't wait to see part 2!
I appreciate your dedication to logging all the different aspects of performance. You will produce good info that is helpful. Toroidel props are being announced as game changers, i hope you have some in those tested.
Daniel, one heck of a kickoff for the series! The setup you built to film this is admittedly just as hard as designing a custom propeller, if not harder. Also, bless you, ya legend.
Well I am impressed. not that anything revolutionary has been found yet. but that this is even happening. you guys are so smart, and so lucky to live in this time. nothing like this was ever available to my generation. keep up the good work folks!
The amount of effort you put into collecting the footage and comparing these is awesome. Can't wait for the next video
19:04 i find it very interesting how the perception of time, filiming and experimenting came togethe to create such an observation.
NIce!
Thanks!
Kudos!