It would have been cool to only have the audio from the under water camera, that way you could hear the noise difference between the small and large propellers. In both watecraft and aircraft, small propellers have the trade-off of making more thrust per unit-area, but being significantly louder. That is one of the main reasons that fighter jets are so much louder than giant passenger aircraft despite having a fraction of the engine power, and why nuclear submarines utilize HUGE propellers that spin very slowly.
I just listened to the pure underwater audio. You're right. Smaller props are louder. :) By the way, that propeller camera was outside the water container. But I had a separate waterproofed Lavalier mic to capture the underwater noises. What you hear on the video is a 50/50 mix of the sound underwater and above it.
@@GerinoMorn Cavitation is caused by a rapid drop in pressure on the trailing edge of the blades, in aerospace the equivalent phenomenon is called 'boundary layer separation', which is the same thing that causes aircraft to stall and lose lift. As far as I'm aware it's simply an issue of your propeller moving too fast for its given blade pitch, so the only solution is to slow the propeller down or reduce pitch, meaning it needs to be larger to make the same thrust. Of course, the larger your propeller is, the faster the tips of the blades are moving at a given RPM, so scaling the size only goes so far.
While I enjoy your build-up-to-the-best-bit style, I want to commend you for the intellectual honesty in getting directly to the showing off all the variations in this large-dataset case which otherwise might have had a very long build-up; not a second wasted, and once you'd shown the most clickbaity part of the video, you investigated each case further. Very respectful of your audience's time, thank you. 🙂
Gramms per Watt would have been useful, but with the gears you also arrived the sweet spot for that motor. Although "static thrust" numbers could be very different to those when boat and prop are both moving fast through water
@@ionstorm66Maybe true, but it would be interesting to see how the different propellers would perform when it comes to top speed and/or efficiency, while the larger props generated a considerable amount of thrust, they also create much more drag and resistance when mounted on a moving boat.
Yeah would be very interesting. But there are the current-numbers and the voltage seems pretty stable. @@ionstorm66 There is no need for high speeds for significant difference to arise.
I love these kinds of videos. Good old empirical science. Test a bunch of stuff, note the result, analyse, learn. Great resource when making boats, planes and helicopters.
Had to stop and re-watch at 0:20 . I legit had thought it was a comically edited failure because of how smooth that piece just gently sank down. Love watching allt he test and trials you come up with. Keep up the awesome work!
I loved the freeze frame on each propeller followed by their dimensions. Made me feel like I was watching a heist flick where all the characters with special abilities are being introduced.
your videos are fantastic, from the editing, building puzzles solved to the top tier data analysis all in an easy to understand presentation WITHOUT saying a word!!!
The non-Lego drone propeller wins that comparison. It gets 60 grams per Watt. From Lego propellers the white long panel 64681 wins it. :) brickexperimentchannel.wordpress.com/2024/04/13/lego-propellers-water-thrust/
TBH I love how you just got straight to the point, and saved the details for later. Everything you needed to know, followed by everything you want to know.
i cant describe how much i love this channel. good, interesting test with good usable results. nothing is over the top and is a very relaxing watch. cant wait for the next sub video!
Excellent static thrust tests! Hoping you have some working LEGO powerboats in the works. During my LEGO powerboat heyday (see channel), tested all existing LEGO props and several easily adaptable non-LEGO props with methods much cruder than yours. The 2-blade 4745 turned out to be the best performer in speed trials, where many factors other than static thrust also come into play. Longer hulls with twin outdrives powered by their own L or XL motors were nearly always fastest. Buddies and I handily won the 2015 Brickworld boat drag race with such a boat fitted with 4745 props. If race rules had allowed us to sand the 4745's slab blades into airfoils, we'd have won by a much bigger margin. Real marine prop blades have airfoil profiles to add forward lift to the thrust generated by simply deflecting water aft. No LEGO prop blades had such profiles at the time. Also no LEGO counter-rotating pairs, which meant lots of propwalk. When not restricted by race rules, we always used 52-55 mm 3-blade counter-rotating props made for hobby-shop RC boats. No LEGO prop could come close in speed trials, with or without blade shaping. Naval architects consider the matching of hulls to powerplants to props something of a black art. Ditto for LEGO powerboats. The key is to arrange for the boat to come to max speed just as the motor's hitting peak mechanical power near 50% no-load shaft speed. That's where gearing becomes critical. Lots of guess-and-check involved.
Great video and i love the editing. Makes it really easy to watch. Would love to see these blades spun up really fast underwater for fun and maybe to find the failure modes.
Can you try to form supercavitation on some props? Would be interesting to see how much RPM each small/medium prop can handle before it starts to form supercavitation...
That 2740c01 brings back memories. It was "the only prop" on the Technic 8855 prop plane set which I still have stowed away in a closet. How to drive it can be a challenge though.
Are the x-axis labels in the bar plots from 5:50 to 14:40 labeled incorrectly? The setup at 3:22 shows the gear ratios ranging from 25:1 to 1:5, but the bar plot axes go from 1:25 to 5:1.
Darn it! The list of gear ratios from 3:22 to 3:50 is incorrect. Everything else is right, including chart x-axis labels and the ratio you see at the bottom left during tests.
That level of comparison and analysis is heads and shoulders above all these RUclips "engineers" that just eyeball the propellers. Looking at you, everyone with 3d-printer who just made something that looks a bit like the MIT toroidal propeller and tried to make comparison videos out of it. There's content and there's scientific content and I think we can see the difference
This is some incredible editing! Plus the effort in collecting the data itself! I know it's just Lego propellers, but I enjoyed watching the video. Thanks!
This gives you a great idea of how well each propeller does under their respective optimal conditions, but what I’d like to see is a data set where all the propellers use the same rpm and gear ratio. That way we can see how the variation of those two factors changes the results. If they’re all taken from the same baseline first, then it gives a frame of reference for their performance under optimal gearing and rpm. It highlights what effects small compromises can have on performance. Someone might use more compact gearing for a smaller project, and get different results because of it.
4:16 small clearance will cause propeller to generate less drag - similar thing we can observe with ducted fans like in turbofans, winglets in planes and with ground effect in low flying planes.
It would be nice if you could make explained videos for some concepts you usually use like gear ratios, torque, and other such engineering concepts for us non engineers to understand
That's cool! It's interesting to see, what's RPM that will make make the motor to generate the most power. And then it's interesting to know, what's the RPM, that will make each propeller to generate the most force/power. We can then see the efficiencies in percents of each propeller.
At first i thought it was just like any good LEGO channel. Then i saw the "Biltema" tachometer, that confirmed my thoughts. Jokes aside, this is great content and i absolutely love the seriousness!
Vibration measurments would be very important. If tou add multiple props/screws to a ship and they vibrate/are too close the wake from them will cause the ship to vibrate, sometime violently. It gets worse the more power the propellers are getting. Oceanlinerdesigns actually had a video covering it, something along the lines of "top greatest ship design failures" or something
Another statistic you should try measuring in the future is thrust to weight, because while bigger and heavier propellers may generate more raw thrust, they might not utilize that thrust as efficiently as lighter models.
Something about the #6041 fan that is so nostalgic. It was used in so many early 2000s wacky sets in underwater, space and plane sets in both earth tones and wild highlighter transparent colors.
You're writing the gear ratios in reverse, it's usually "output:input", a reduction (propeller slower than the motor) would be 1:3, not 3:1 like you're writing
Such a good video. My only scientific thought is the size of the container is limiting, in that it bounces the water back towards the propeller and alters the result. Still, minor quibble and probably wouldn't make a significant difference!
For the slippery one that required tape to be solid, you could’ve marked it (with a line on tape and prop) to see how much it rotated (if at all) after spinning.
For the 64683 Technic, Panel Fairing, you could try variable pitch and see what pitch works best. The tests are absolutely awesome in any case! I love it :)
Great Video. Would be Interesting to see the different performance patterns in active flow. A lot of Props can create really unintuitive thrust when measured in an active flow scenario.
Something thats important (but probably harder to measure) is the blade's surface area. The propeller at 10:10 is kinda just brute forcing its strength, and is quite inefficient (but cool nonetheless)
it was fascinating to see the difference between CW and CCW thrust may be sorta dependent on the difference of the pitch angles of the 2 sides of the propellers!! thank you for making such amazing videos! love the whole thing!
Wow, quite the deep dive (no pun intended). I had no idea there were so many different propeller options. I assume this is part of a larger series of experiments to optimize a Lego boat or submarine? My only disappointment is you didn't make a 10-speed transmission, to avoid having to change out the propeller so often. Or even a CVT to optimize the RPMs even more.
I am wondering about something. Why are 64683 (9:27) and 2740c01 (12:26) so imbalanced? Everything else was relatively fine but those two were all over the place.
please remember pluber's tape is specifically designed for LOW friction if you look at many of the plumbers tape they only perform well at low gear ratios. likelyy because higher ones slip.
There's another 3-blade Lego prop. 1x Technic hub w/ 3 axles 3x 1x2 inverted slope 3x 1x2 plate 6x 1x1 cheese slope The thin end of the 1x2 slope makes the "scoop" of the blade
would be interesting to see a graph of wattage vs thrust for each prop at ideal gear ratio. I know the V/A were shown on screen but i think it would be neat for any future projects in this style.
Just straight into action. No intro, no sponsors, no bs. Love these kinds of channels
Fr
can u recommend any other channels like this boss
@@nissanoo0393Primitive Technology, Cutting Edge Engineering Australia, Matthias Wandel, Code Bullet
Yes🎉
@@nissanoo0393primitive technology but instead if lego it's nature
It would have been cool to only have the audio from the under water camera, that way you could hear the noise difference between the small and large propellers. In both watecraft and aircraft, small propellers have the trade-off of making more thrust per unit-area, but being significantly louder. That is one of the main reasons that fighter jets are so much louder than giant passenger aircraft despite having a fraction of the engine power, and why nuclear submarines utilize HUGE propellers that spin very slowly.
There is a point where cavitation becomes an issue, right? And you get that ultra-loud collapsing bubble thing...
I just listened to the pure underwater audio. You're right. Smaller props are louder. :)
By the way, that propeller camera was outside the water container. But I had a separate waterproofed Lavalier mic to capture the underwater noises. What you hear on the video is a 50/50 mix of the sound underwater and above it.
@@GerinoMornahead flank; emergency speed. warning! vessel cavitating; excessive noise!
@@GerinoMorn Cavitation is caused by a rapid drop in pressure on the trailing edge of the blades, in aerospace the equivalent phenomenon is called 'boundary layer separation', which is the same thing that causes aircraft to stall and lose lift. As far as I'm aware it's simply an issue of your propeller moving too fast for its given blade pitch, so the only solution is to slow the propeller down or reduce pitch, meaning it needs to be larger to make the same thrust. Of course, the larger your propeller is, the faster the tips of the blades are moving at a given RPM, so scaling the size only goes so far.
@@mikieswartEject decoy!
the fact that you are testing propellers makes me wonder if you are planning on revisiting your Lego submarine.
kinda seems like an anual tradition at this point
While I enjoy your build-up-to-the-best-bit style, I want to commend you for the intellectual honesty in getting directly to the showing off all the variations in this large-dataset case which otherwise might have had a very long build-up; not a second wasted, and once you'd shown the most clickbaity part of the video, you investigated each case further. Very respectful of your audience's time, thank you. 🙂
top tier data analysis, im fully satisfied
Gramms per Watt would have been useful, but with the gears you also arrived the sweet spot for that motor. Although "static thrust" numbers could be very different to those when boat and prop are both moving fast through water
To be fair I doubt a Lego powered boat is going to move fast enough the dynamic thrust will be too different then the static thrust.
@@ionstorm66Maybe true, but it would be interesting to see how the different propellers would perform when it comes to top speed and/or efficiency, while the larger props generated a considerable amount of thrust, they also create much more drag and resistance when mounted on a moving boat.
Yeah would be very interesting. But there are the current-numbers and the voltage seems pretty stable.
@@ionstorm66 There is no need for high speeds for significant difference to arise.
Good idea with the grams per Watt. I added that comparison to the blog.
brickexperimentchannel.wordpress.com/2024/04/13/lego-propellers-water-thrust/
Just a little warning, these results are valid at 7V, closest to that is 6x rechargable AA batteries.
I love these kinds of videos. Good old empirical science. Test a bunch of stuff, note the result, analyse, learn. Great resource when making boats, planes and helicopters.
Had to stop and re-watch at 0:20 . I legit had thought it was a comically edited failure because of how smooth that piece just gently sank down.
Love watching allt he test and trials you come up with. Keep up the awesome work!
I loved the freeze frame on each propeller followed by their dimensions. Made me feel like I was watching a heist flick where all the characters with special abilities are being introduced.
Bro's the top lego engineer 🗿
I wish it had 3d lego propellers
“Bro-“
Brainrot
@@muffinconsumer4431 ok bro
@@Malfin_L Bro said ok bro
@@muffinconsumer4431 ok bro
Really educational!
Anybody else find this really weirdly relaxing? Just a quiet video with no dialogue and some experimenting
It's just like childhood lego experiments in your room
Just like Primitive technology. (The OG, not the horrible ones with music and click bait building "underground pools"
My man trying to teach us mechanical engineering and thinking we wouldn't notice
its crazy how much more power some of the much smaller ones put out in comparison to the larger ones
your videos are fantastic, from the editing, building puzzles solved to the top tier data analysis all in an easy to understand presentation WITHOUT saying a word!!!
THIS is peak content. Densely packed with information. Good testing procedures. Great usage of graphics. Legos!
Helicopter helicopter
Paaaara kofer paara kofer 🗿
You guys are 3 years late.
@@Nomaditishelicopter helicopter
Badger badger
Yes, Papa?
He is studying for the next Submarine!
Nahh that's wild why😭
@@Bocchi-the-wideI bet some of the components on that submarine were made of Lego.
@@Bocchi-the-wide He is talking about the Lego submarines BEC has made.
As propellers are tested at zero forward speed it is more useful to be compared in term of "figure of merit"(thrust/shaft power)
Next we need to know which design is the most efficient: thrust vs. power draw
BTW: good work!
The non-Lego drone propeller wins that comparison. It gets 60 grams per Watt. From Lego propellers the white long panel 64681 wins it. :)
brickexperimentchannel.wordpress.com/2024/04/13/lego-propellers-water-thrust/
TBH I love how you just got straight to the point, and saved the details for later. Everything you needed to know, followed by everything you want to know.
Wake up
BEC uploaded a new video
I appreciate how scientifically rigorous and well documented this is. Good experiment 👏
i cant describe how much i love this channel. good, interesting test with good usable results. nothing is over the top and is a very relaxing watch. cant wait for the next sub video!
Man the editing here is hella clean, very nice video, and the processes were very clearly laid out which is fantastic
props for this test and the editing
Excellent static thrust tests! Hoping you have some working LEGO powerboats in the works.
During my LEGO powerboat heyday (see channel), tested all existing LEGO props and several easily adaptable non-LEGO props with methods much cruder than yours. The 2-blade 4745 turned out to be the best performer in speed trials, where many factors other than static thrust also come into play.
Longer hulls with twin outdrives powered by their own L or XL motors were nearly always fastest. Buddies and I handily won the 2015 Brickworld boat drag race with such a boat fitted with 4745 props. If race rules had allowed us to sand the 4745's slab blades into airfoils, we'd have won by a much bigger margin.
Real marine prop blades have airfoil profiles to add forward lift to the thrust generated by simply deflecting water aft. No LEGO prop blades had such profiles at the time. Also no LEGO counter-rotating pairs, which meant lots of propwalk.
When not restricted by race rules, we always used 52-55 mm 3-blade counter-rotating props made for hobby-shop RC boats. No LEGO prop could come close in speed trials, with or without blade shaping.
Naval architects consider the matching of hulls to powerplants to props something of a black art. Ditto for LEGO powerboats. The key is to arrange for the boat to come to max speed just as the motor's hitting peak mechanical power near 50% no-load shaft speed. That's where gearing becomes critical. Lots of guess-and-check involved.
Great video and i love the editing. Makes it really easy to watch.
Would love to see these blades spun up really fast underwater for fun and maybe to find the failure modes.
You can *really* see the difference in directional thrust from the ones with an actual aero/hydrofoil shape to the blades, wow.
Gotta go tell my gf that 15cm is indeed considered huge
Nah bro, that's massive
😂😂😂
No.
No
Can you try to form supercavitation on some props? Would be interesting to see how much RPM each small/medium prop can handle before it starts to form supercavitation...
I adore your straightforward and well thought out procedures!! Very good visual explanation of iteration on ideas and problem solving
Very cool results and very thorough test procedure!
Thank you for going over the set up for testing too.
How does one acquire so much red technic pieces?
eBay.
*That's great, my friend. I tried Vortex experiments like yours!!! IT'S quite interesting* 🤗🤗🤗🤗🤗
Your experiments are also very cool
I love both channels. So fun and cool 😋
This is so thorough that I can't even think of something to add! Great job!
Props to you for doing these experiments.
Hehe
That 2740c01 brings back memories. It was "the only prop" on the Technic 8855 prop plane set which I still have stowed away in a closet. How to drive it can be a challenge though.
Are the x-axis labels in the bar plots from 5:50 to 14:40 labeled incorrectly? The setup at 3:22 shows the gear ratios ranging from 25:1 to 1:5, but the bar plot axes go from 1:25 to 5:1.
Darn it! The list of gear ratios from 3:22 to 3:50 is incorrect. Everything else is right, including chart x-axis labels and the ratio you see at the bottom left during tests.
Nice video, like your Lego techniques a lot
you have not even finished the vid yet
I really would like to see the input power that each was driven at
The data is there: power is voltage times current. So e.g. at 12:10 it's: 7 V × 0.78 A = 5.46 W
I'd love to see a test of which of these could generate enough push to propel a boat!
Never a dull upload with this channel that’s for sure 👍
That level of comparison and analysis is heads and shoulders above all these RUclips "engineers" that just eyeball the propellers. Looking at you, everyone with 3d-printer who just made something that looks a bit like the MIT toroidal propeller and tried to make comparison videos out of it.
There's content and there's scientific content and I think we can see the difference
This is some incredible editing! Plus the effort in collecting the data itself! I know it's just Lego propellers, but I enjoyed watching the video. Thanks!
id love to read the research paper you make from this
Fascinating as always
This gives you a great idea of how well each propeller does under their respective optimal conditions, but what I’d like to see is a data set where all the propellers use the same rpm and gear ratio. That way we can see how the variation of those two factors changes the results. If they’re all taken from the same baseline first, then it gives a frame of reference for their performance under optimal gearing and rpm. It highlights what effects small compromises can have on performance. Someone might use more compact gearing for a smaller project, and get different results because of it.
Everything about your videos are so efficient and informative
this is incredibly in-depth and i appreciate your deligence
The instrumentation an attention to detail is great, data can be fascinating stuff.
Surprisingly advanced methodology
4:16 small clearance will cause propeller to generate less drag - similar thing we can observe with ducted fans like in turbofans, winglets in planes and with ground effect in low flying planes.
Wow, that is incredibly thorough testing. Well done!
What is the song at 1:03 called?
It's in the description
"Heaven and Hell - Jeremy Blake"
@@xerveeonthanks
This feels like a college project for a fluid dynamics class. Well done!
It would be nice if you could make explained videos for some concepts you usually use like gear ratios, torque, and other such engineering concepts for us non engineers to understand
Bravo! Next step: A marine "wind" tunnel where you can test variable pitch against flow rate and give us some sweet 3D plots :)
Thanks for all the time and effort for great data!
That's cool! It's interesting to see, what's RPM that will make make the motor to generate the most power. And then it's interesting to know, what's the RPM, that will make each propeller to generate the most force/power. We can then see the efficiencies in percents of each propeller.
At first i thought it was just like any good LEGO channel. Then i saw the "Biltema" tachometer, that confirmed my thoughts. Jokes aside, this is great content and i absolutely love the seriousness!
I'm going to sit here in almost silence admiring the time and effort this took you to make, this is incredible.
This is like Project Farm but for Lego. This man must also be protected at all costs.
Fantastic video, as always.
I would have loved to see some efficiency comparison as well (power/thrust), maybe next time :P
1:41 what is that music from i swear its from like cosmo or somthing ?
now this is the answer thati never thought to question, very interesting results.
What will happen if testing these propellers in an air tunnel?
There are too many variables, but it's very nice and detailed
and arranged very neatly and meticulously making it easy to understand
It is clear that difficult work has been done. Like. 👍
Vibration measurments would be very important. If tou add multiple props/screws to a ship and they vibrate/are too close the wake from them will cause the ship to vibrate, sometime violently. It gets worse the more power the propellers are getting.
Oceanlinerdesigns actually had a video covering it, something along the lines of "top greatest ship design failures" or something
Another statistic you should try measuring in the future is thrust to weight, because while bigger and heavier propellers may generate more raw thrust, they might not utilize that thrust as efficiently as lighter models.
Performance curves of lego propellers... top tier content right here.
I love that somewhere, someone is going to find this incredibly useful for their own project
Something about the #6041 fan that is so nostalgic. It was used in so many early 2000s wacky sets in underwater, space and plane sets in both earth tones and wild highlighter transparent colors.
Nice to see the old ZNAP wheels being given a chance! I still have a lot of that stuff somewhere.
With all this data collected, when are you releasing the paper
Cool Lego experiments, man! I hope they get better and better every day with each and every video you make. Awesome job, man! 👏🏻 👏🏻
You're writing the gear ratios in reverse, it's usually "output:input", a reduction (propeller slower than the motor) would be 1:3, not 3:1 like you're writing
Huh. The way I learned it, a reduction would be 3:1.
Geniunely astounded that some of the diy ones did better than the first few
Such a good video. My only scientific thought is the size of the container is limiting, in that it bounces the water back towards the propeller and alters the result. Still, minor quibble and probably wouldn't make a significant difference!
For the slippery one that required tape to be solid, you could’ve marked it (with a line on tape and prop) to see how much it rotated (if at all) after spinning.
Captivating video. Love all the graphics you showed
I don’t know what I personally will ever do with any of this information. But, as someone who loves running numbers/data and Lego, I’m down for it
Awesome.
I would love to see some lego impellers.
Or, better yet VSP-style cyclorotors.
Babe, wake up. Brick Experiment Channel just posted a new video.
For the 64683 Technic, Panel Fairing, you could try variable pitch and see what pitch works best.
The tests are absolutely awesome in any case! I love it :)
Great Video. Would be Interesting to see the different performance patterns in active flow. A lot of Props can create really unintuitive thrust when measured in an active flow scenario.
But no clue how you can create such a test structure.
Something thats important (but probably harder to measure) is the blade's surface area. The propeller at 10:10 is kinda just brute forcing its strength, and is quite inefficient (but cool nonetheless)
it was fascinating to see the difference between CW and CCW thrust may be sorta dependent on the difference of the pitch angles of the 2 sides of the propellers!!
thank you for making such amazing videos! love the whole thing!
Now do some Lego Ocean Gate pressure testing lmao
Wow, quite the deep dive (no pun intended). I had no idea there were so many different propeller options. I assume this is part of a larger series of experiments to optimize a Lego boat or submarine?
My only disappointment is you didn't make a 10-speed transmission, to avoid having to change out the propeller so often. Or even a CVT to optimize the RPMs even more.
I am wondering about something. Why are 64683 (9:27) and 2740c01 (12:26) so imbalanced? Everything else was relatively fine but those two were all over the place.
please remember pluber's tape is specifically designed for LOW friction
if you look at many of the plumbers tape they only perform well at low gear ratios. likelyy because higher ones slip.
Would have loved to see a toroidal propeller in here! Very nice video.
who would win?
(0:09)BIG BOY CUSTOM
or
mini prop
Make working replica of engine using vacuum
Huge props to this channel!
There's another 3-blade Lego prop.
1x Technic hub w/ 3 axles
3x 1x2 inverted slope
3x 1x2 plate
6x 1x1 cheese slope
The thin end of the 1x2 slope makes the "scoop" of the blade
would be interesting to see a graph of wattage vs thrust for each prop at ideal gear ratio. I know the V/A were shown on screen but i think it would be neat for any future projects in this style.
Volts * Amps = watts