I have been curious about how the size and shape of a propeller affect its efficiency for a long time. I tested some propellers that I found in my drawer. I hope you find my experiment interesting!
It was fun, but it felt like it lacked the basic understanding of aerodynamics. I suggest you try the same tests next using smoke, then you'll understand a lot of misconceptions about how these stuff works. Like why the ball did not move close to the propeller but was sped up at a distance, or why non wing like "propellers" did not work.
@DrEngine It was very interesting! Thank you! 4:40 As a building tip, though, when building custom-made propellers using LEGO Technic panels like this, try not to build perpendicular to the axis of rotation like you did in this video, as the centrifugal force acts outwards on the propeller blades. What I mean by that is, try using pairs of either the 3L Technic universal joints (for controllable and variable-pitch propellers) or the 3L Technic angled axle connectors to mount the blades parallel to the axle or axis of rotation, and reinforce the blade connections on both the bottom and top halves of the propeller hub. 3L Perpendicular Pin and Axle connectors can be used to mount the blades onto the hub. I've found that this design is much more resistant to centrifugal force and can hence spin at much higher speeds (even ludicrous BuWizz or buggy motor speeds) without breaking apart. I will provide links to the parts I am talking about below. www.bricklink.com/v2/catalog/catalogitem.page?P=42003#T=S&O={%22iconly%22:0} www.bricklink.com/v2/catalog/catalogitem.page?P=32016#T=S&O={%22iconly%22:0} www.bricklink.com/v2/catalog/catalogitem.page?P=62520c01#T=S&O={%22iconly%22:0} Hopefully this helps! :)
@@Sonnell The ball did not move closer to the propeller because thrust from the propeller was exerting a forward force on the ball until the force of gravity interrupted the ball's motion (on steeper inclines). And non-wing propellers can work as long as each blade is set an angle, they are just less efficient than propellers with more aerodynamic blade types. Moreover, the propeller failure at timestamp 4:40 resulted from a structural integrity issue directly related to the propeller's design, not its aerodynamic performance. Centrifugal force acted outwards on the blades and overcame the frictional forces that held those blades to the propeller hub.
+1 for the Hot Wheels track! Such a bummer to spend the time build up something like the 'wheel' only to find it completely ineffective. All AFOLs know this pain. Thank you!
I see several ways this test can be improved. 1) The tilted track means that at the higher levels, the propeller is no longer blowing along the axis of travel. A better setup would be if the track was attached directly to the motor frame, and the entire assembly was tilted. 2) Not all of the tests were at the same distance from the axis of rotation. A better setup would be three tracks, one at the bottom edge of the propeller, one at the center, and one at the top. The bottom one would trap air against the track, while the top would not, allowing comparison. 3) There are no really useful metrics. For an apples to apples comparison, make the track(s) longer, tilt them at 30 or 45 degrees, and attach a scale to the tracks. The propeller pushes the balls up the track, but it is long enough that the ball(s) 7:43 eventually stalls before reaching the end of the track. Measure the distance to get a comparable metric.
also have the same amount of power behind each of the fans instead of changing it. that really messes it up when available power is changing (some of the earlier fans would have benefitted from more power but you didn't give them it then you gave later ones more power) unless you did keep the same number moters
The wheel is pretty much just a large centrifugal fan which pulls air through the middle and flings it to the outside. You usually see them inside a cowling with one outlet for directing all that airflow to one area (usually inside someplace that needs cooling)
It's a bit of a flawed test, not only because the ball will just let the air flow around it and/or leave the air current as it ascends. Perhaps try propeller designs on a vehicle on rails, then you can measure both the weight and speed the designs can move?
More blades doesn't equal more wind. It's actually negatively affecting the amount of moved air by decreasing the efficiency of the vortex. Same reason boats or wind turbines usually only have 3 blades on a propeller. It's a fascinating science actually. I recommend looking it up.
I feel like the rotational speed and generated windspeeds aren't as much of a factor if the fan isn't large enough to direct its wind at the ball anymore, no? That's why most of the fans top out at Level 5.
It’d be cool to compare ducted designs! Or maybe even multi-stage setups with progressive RPM on the addition fan stages? Or additional vanes after the fan to create laminar flow, which would increase the distance the air travels?
I heard somewhere that propellers with more blades can apply more force per RPM but can't be spun as quickly. looking at the chart, the 2B9D and the 3B9D produce the same amount of wind, with the 3B9D being slightly slower. I think this is true, but there might be inefficiencies which causes the level to not coincide.
For some runs with small propellers, especially where they do not hit ~70% of max RPM, it would be good to test to remove the last reductor stage, for more torque & less friction
Many of the props you have running in reverse. Take note of the aerofoil. The rounded edge leads the way. NOT the sharp edge. Had you used a snail scroll blower, you'd have sent that ping pong ball vertical.
There is a maximum power for the first half of the tests. A more effective prop takes more power so you end up with nothing but the 2 blade getting past 5 until the ducted fans.
now make a flying plane built out of lego using this knowledge... It's probably impossible but with enough wing span and really light build, maybe the body just made out of cross axle rods and some fabric or vinyl for wings, and using a small non-lego motor with small battery it could be possible. Or maybe a rubber band plane? Would be cool Lego achievement nonetheless.
If RPM's drops from maximum and wind speed stays almost same going to different propeller, than it tels you, you have not enought power. First few tests is not valid due to motor not being powerfull enought to drive all attached propellers at 11k rpm's. At that point you are not testing propellers, but motor.
I enjoyed this video, but I would also like if you performed the tests again with more scientific rigor, using some of the comment suggestions like testing all the blades flipped around too, aligning the fan direction with the incline, and testing different gearing for the fans to see which gearing works best for each one.
I found this video very interesting. Thanks You might want to try one (or more) of your propellers with a single motor and different gear ratios. There will be a 'sweet spot' where 'matching' the propeller to the motor is best. Just a thought
Wouldn't it make sense to tilt the propellor in line to the desired direction of travel of the ball? You might have a propellor capable of lifting the ball vertically, but if you put the rail perpendicular, the ball won't move...
Algumas helices foram montadas ao contrario. Helice tem lado e isso influencia drasticamente no resultado. O lado da pá que é convexo deve ficar virado pra onde entra o ar na hélice, o lado concavo deve ficar virado pra onde o ar sai.
Wouldnt the Propeller 3 Blade 13 Diameter work better flipped around? Im just judging by the shape of the blades. Wouldnt it also be able to take in more air because of the curve?
Nahw, you forgot to turn the white rotor blades by 90° - it will push much more are (and also creating much more resistance :D) Besides that little miss it isnice content, thanks ♥
I have been curious about how the size and shape of a propeller affect its efficiency for a long time. I tested some propellers that I found in my drawer. I hope you find my experiment interesting!
It was educational and fun! Thank you!👍👍👍
It was fun, but it felt like it lacked the basic understanding of aerodynamics. I suggest you try the same tests next using smoke, then you'll understand a lot of misconceptions about how these stuff works. Like why the ball did not move close to the propeller but was sped up at a distance, or why non wing like "propellers" did not work.
@DrEngine It was very interesting! Thank you!
4:40 As a building tip, though, when building custom-made propellers using LEGO Technic panels like this, try not to build perpendicular to the axis of rotation like you did in this video, as the centrifugal force acts outwards on the propeller blades. What I mean by that is, try using pairs of either the 3L Technic universal joints (for controllable and variable-pitch propellers) or the 3L Technic angled axle connectors to mount the blades parallel to the axle or axis of rotation, and reinforce the blade connections on both the bottom and top halves of the propeller hub. 3L Perpendicular Pin and Axle connectors can be used to mount the blades onto the hub. I've found that this design is much more resistant to centrifugal force and can hence spin at much higher speeds (even ludicrous BuWizz or buggy motor speeds) without breaking apart. I will provide links to the parts I am talking about below.
www.bricklink.com/v2/catalog/catalogitem.page?P=42003#T=S&O={%22iconly%22:0}
www.bricklink.com/v2/catalog/catalogitem.page?P=32016#T=S&O={%22iconly%22:0}
www.bricklink.com/v2/catalog/catalogitem.page?P=62520c01#T=S&O={%22iconly%22:0}
Hopefully this helps! :)
@@Sonnell The ball did not move closer to the propeller because thrust from the propeller was exerting a forward force on the ball until the force of gravity interrupted the ball's motion (on steeper inclines). And non-wing propellers can work as long as each blade is set an angle, they are just less efficient than propellers with more aerodynamic blade types. Moreover, the propeller failure at timestamp 4:40 resulted from a structural integrity issue directly related to the propeller's design, not its aerodynamic performance. Centrifugal force acted outwards on the blades and overcame the frictional forces that held those blades to the propeller hub.
Very funny Videos! 😊
The wind detector falling over was a task failed successfully
FR
You have been running some props in the wrong direction. Best test them in both directions
Also different amounts of power in each run.
go-go gagit pixel reducer 0:01
OH NO THE PIXELS! WHERE THEY'RE GOING?!
[screams in 8p]
Correct directions
AAAAA
Your design choice to put the 3 flags along the ramp really drew me in: Flag 1, Flag 2, Flag 3, The Box!!! Loved it ~ thank you 😊
Glad you like them!
hi
4:21 THAT COUNTS???? hahahha aah omg you got me good
Lmfao
Yeah lol
😂
I was thinking the same thing
+1 for the Hot Wheels track! Such a bummer to spend the time build up something like the 'wheel' only to find it completely ineffective. All AFOLs know this pain. Thank you!
I see several ways this test can be improved.
1) The tilted track means that at the higher levels, the propeller is no longer blowing along the axis of travel. A better setup would be if the track was attached directly to the motor frame, and the entire assembly was tilted.
2) Not all of the tests were at the same distance from the axis of rotation. A better setup would be three tracks, one at the bottom edge of the propeller, one at the center, and one at the top. The bottom one would trap air against the track, while the top would not, allowing comparison.
3) There are no really useful metrics. For an apples to apples comparison, make the track(s) longer, tilt them at 30 or 45 degrees, and attach a scale to the tracks. The propeller pushes the balls up the track, but it is long enough that the ball(s) 7:43 eventually stalls before reaching the end of the track. Measure the distance to get a comparable metric.
Amazing tips, thank you!
also have the same amount of power behind each of the fans instead of changing it. that really messes it up when available power is changing (some of the earlier fans would have benefitted from more power but you didn't give them it then you gave later ones more power) unless you did keep the same number moters
Ну ты душнила...
You have to tilt the rotor as much as the slope to keep the force and it's vector constant
greate video bro!👍👍
Thanks! 👍
Another amazing feat of LEGO engineering!
Absolutely loved this video since I always wanted to know which propeller worked best
Great to hear!
The wheel is pretty much just a large centrifugal fan which pulls air through the middle and flings it to the outside. You usually see them inside a cowling with one outlet for directing all that airflow to one area (usually inside someplace that needs cooling)
Thanks for the info!
Maybe try to make a cilinder around some of them to funnel the wind?
Nice suggestion!
0:07 I like the sound at speed 2×! Cool noise!
Thank you so much for the informative video! The video quality is incredibly high! I am impressed!!!
Glad you enjoyed it!
Hey the flaps on the fan you maid is reversed that's why it didn't work@@DrEngine
Great video! However, like all your previous ones👍🔥
Glad you like them!
It's a bit of a flawed test, not only because the ball will just let the air flow around it and/or leave the air current as it ascends.
Perhaps try propeller designs on a vehicle on rails, then you can measure both the weight and speed the designs can move?
Кто нибудь, откройте окно. Здесь слишком душно.
Man I love seeing propeller pieces when I was a child
the effort put into these videos is amazing
More blades doesn't equal more wind. It's actually negatively affecting the amount of moved air by decreasing the efficiency of the vortex. Same reason boats or wind turbines usually only have 3 blades on a propeller. It's a fascinating science actually. I recommend looking it up.
So, What makes more blades?
I feel like the rotational speed and generated windspeeds aren't as much of a factor if the fan isn't large enough to direct its wind at the ball anymore, no? That's why most of the fans top out at Level 5.
You're right! That’s why fans often have a top speed-they reach a point where more power doesn't enhance the airflow in a meaningful way.
It’d be cool to compare ducted designs! Or maybe even multi-stage setups with progressive RPM on the addition fan stages? Or additional vanes after the fan to create laminar flow, which would increase the distance the air travels?
Putting in the propellers it just so satisfying
love your channel
3:22 The ball was flying ✈️✈️✈️
4:51 It broke but it still did it😂😂😂😮😮😮 The ball was like levitating
i NEED to get those 14L blades, will help a lot in this summer
nvm prob unavailable
bro had such a good first try that it took a redesign and 9 other tries to beat it lmao
7:55 that "flop" made my day! 😂 so unexpected, yet so incredibly funny!!😂😂
Everybody do the flop
Amazing ❤❤
Thank you! Cheers!
I heard somewhere that propellers with more blades can apply more force per RPM but can't be spun as quickly.
looking at the chart, the 2B9D and the 3B9D produce the same amount of wind, with the 3B9D being slightly slower.
I think this is true, but there might be inefficiencies which causes the level to not coincide.
You're always so creative with your ideas. I'm always excited to see what you come up with next.
For some runs with small propellers, especially where they do not hit ~70% of max RPM, it would be good to test to remove the last reductor stage, for more torque & less friction
Many of the props you have running in reverse. Take note of the aerofoil. The rounded edge leads the way. NOT the sharp edge.
Had you used a snail scroll blower, you'd have sent that ping pong ball vertical.
Lego x HotWheels x White Ball, never expected such a collab!
1:01
One must imagine Sisyphus happy
good video, thanks for sharing
There is a maximum power for the first half of the tests. A more effective prop takes more power so you end up with nothing but the 2 blade getting past 5 until the ducted fans.
That one Propeller just ripped apart
There’s official Leto rotor pieces, many from Lego city helicopters, would be cool to see them
That´s amazing!! Greetings from Brasil!
now make a flying plane built out of lego using this knowledge... It's probably impossible but with enough wing span and really light build, maybe the body just made out of cross axle rods and some fabric or vinyl for wings, and using a small non-lego motor with small battery it could be possible. Or maybe a rubber band plane? Would be cool Lego achievement nonetheless.
The lego one is like a sounds like helicopter propeller broking
my fyp be like! he woill watch anything
2:14 that use for water
7:56 bro make an whole tornado
Great propeller invention
6:10 bro just want to move near the ball 💀
6:12 you almost had a Centrifugal here, just needed to block off the Backplate and add a Case.
Amazing video ❤
Part 2 with counter rotating blades
Noted!
If RPM's drops from maximum and wind speed stays almost same going to different propeller, than it tels you, you have not enought power. First few tests is not valid due to motor not being powerfull enought to drive all attached propellers at 11k rpm's. At that point you are not testing propellers, but motor.
or shows the influence of the propeller on the engine ;)
He needs to use a brushless motor or put more motors
good video :33
Thanks for watching
I noticed(as some others have also stated) that some of the propellers seemed to have been spun backwards
I enjoyed this video, but I would also like if you performed the tests again with more scientific rigor, using some of the comment suggestions like testing all the blades flipped around too, aligning the fan direction with the incline, and testing different gearing for the fans to see which gearing works best for each one.
I found this video very interesting.
Thanks
You might want to try one (or more) of your propellers with a single motor and different gear ratios.
There will be a 'sweet spot' where
'matching' the propeller to the motor is best.
Just a thought
Thanks for the tips!
I know this might be extremely hard to do but what if you tried Contra-rotating props? The Antonov an70 has them
The truth is that having many blades does not mean the wind will be strong
Most ships used three blades, because the drag lower the rpm and use more fuel
Wouldn't it make sense to tilt the propellor in line to the desired direction of travel of the ball?
You might have a propellor capable of lifting the ball vertically, but if you put the rail perpendicular, the ball won't move...
I think a small propeller might've done it too if it had a cowl around it.
The first level five edged me so bad bro
6:42 turning OSHA into OSHI-
4:37 cool
The more complicated propellers cause more turbulence than airflow
i am a big fan of your woke kip it up😁
I like the idea but you really should’ve made a stronger structure for the big heavy propellers and held them down to use them most effectively
Can you do a tutorial or show how to connect your Lego engine to your volt thing
Wow! You’re doing great work and I hope you are able to best! 😊
Thank you so much!
Cool
adding more blades increases the drag
今学校で歯車使った学習してるからこのすごさがすごくわかる😊
4:16 Me: It was almost there!!!😢😢😢
The final one its like neptune's winds
Let's make some noise 😊
Have you tried combining solar panel with Lego?😎👍
Algumas helices foram montadas ao contrario. Helice tem lado e isso influencia drasticamente no resultado. O lado da pá que é convexo deve ficar virado pra onde entra o ar na hélice, o lado concavo deve ficar virado pra onde o ar sai.
i feel like it was not a good test because of how the wind would blow the more focused the stream of air the better it would be
You should have angled the fans with the ramp
For some reason the white ones seem to work best
Nice!
Wouldnt the Propeller 3 Blade 13 Diameter work better flipped around? Im just judging by the shape of the blades. Wouldnt it also be able to take in more air because of the curve?
The wheel was beating up the track
Nahw, you forgot to turn the white rotor blades by 90° - it will push much more are (and also creating much more resistance :D)
Besides that little miss it isnice content, thanks ♥
Thanks for the tip!
Increasing the number of blades does not always lead to better results... 🤔
7:16 I like the 3 bladed fan blades, Sounds like a air conditioner, Build one
very cool
3:50 I thought the wind could be stronger but when it was level three it already failed 😭😭😭
go-go gadget pixel reducer
looks like size really does matter
Nuevo suscriptor
And now, we know. 😂
can you do a drone next??
nice
Planetary gearbox/gearset when?
4:20 - Screw it
Why didn't you use counter-rotating propellers?
What is that white lego part that likes lego?
Is the Model "WW" model a "Water Wheel" ?
6:12 i think your spinning the "wheel" the wrong way
6:09 washing machine Indesit motor drum noise 1000 rpm
1:28 Rolling Shatter
Братишко мы знаем что ты русский