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.
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
+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!
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)
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.
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?
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
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.
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?
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.
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.
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.
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 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.
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 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
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?
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! 😊
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
The wind detector falling over was a task failed successfully
FR
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...
+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!
You have to tilt the rotor as much as the slope to keep the force and it's vector constant
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
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!
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?
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?
bro had such a good first try that it took a redesign and 9 other tries to beat it lmao
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
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.
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.
Maybe try to make a cilinder around some of them to funnel the wind?
Nice suggestion!
2:14 that use for water
7:56 bro make an whole tornado
my fyp be like! he woill watch anything
0:07 I like the sound at speed 2×! Cool noise!
It makes me so happy seeing people who are really passionate with lego, and actually post videos frequently ❤
Man I love seeing propeller pieces when I was a child
I noticed(as some others have also stated) that some of the propellers seemed to have been spun backwards
That one Propeller just ripped apart
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.
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
the effort put into these videos is amazing
What is that white lego part that likes lego?
Most ships used three blades, because the drag lower the rpm and use more fuel
Absolutely loved this video since I always wanted to know which propeller worked best
Great to hear!
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😊
4:51 It broke but it still did it😂😂😂😮😮😮 The ball was like levitating
Gg
7:55 that "flop" made my day! 😂 so unexpected, yet so incredibly funny!!😂😂
Everybody do the flop
There’s official Leto rotor pieces, many from Lego city helicopters, would be cool to see them
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
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
The more complicated propellers cause more turbulence than airflow
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.
adding more blades increases the drag
Another amazing feat of LEGO engineering!
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.
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 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
Planetary gearbox/gearset when?
For some reason the white ones seem to work best
You should have angled the fans with the ramp
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.
2 of those are boat propellers, not aircraft.
6:10 bro just want to move near the ball 💀
Putting in the propellers it just so satisfying
6:42 turning OSHA into OSHI-
The truth is that having many blades does not mean the wind will be strong
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
4:20 - Screw it
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
I know this might be extremely hard to do but what if you tried Contra-rotating props? The Antonov an70 has them
Lego x HotWheels x White Ball, never expected such a collab!
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!
Have you tried combining solar panel with Lego?😎👍
Increasing the number of blades does not always lead to better results... 🤔
3:22 The ball was flying ✈️✈️✈️
looks like size really does matter
6:12 you almost had a Centrifugal here, just needed to block off the Backplate and add a Case.
4:22 cheating
Great propeller invention
1:01
One must imagine Sisyphus happy
The wheel was beating up the track
Can you do a tutorial or show how to connect your Lego engine to your volt thing
greate video bro!👍👍
Thanks! 👍
i NEED to get those 14L blades, will help a lot in this summer
nvm prob unavailable
can you do a drone next??
Great video! However, like all your previous ones👍🔥
Glad you like them!
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!
The final one its like neptune's winds
You're always so creative with your ideas. I'm always excited to see what you come up with next.
love your channel
4:37 cool
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.
Amazing video ❤
Part 2 with counter rotating blades
Noted!
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?
Why didn't you use counter-rotating propellers?
❤besti legó spilari ❤
"Cross" because it "Crosses" the room
Is the Model "WW" model a "Water Wheel" ?
5:36 "the wheel" looks to be more of a plane looking engine. keep in mind those engines are intake
Bro, the 3 blade 3 diameter. Looks like it could be used for a boat. So yeah, for the next newer video. You should make a very fast hydroplane boat.
6:12 i think your spinning the "wheel" the wrong way
Wow! You’re doing great work and I hope you are able to best! 😊
Thank you so much!
Model wheel = Model washing machine
What do you mean "6 diameter"? 6 what?
The blades of the propellers diameter
Six studs
Amazing ❤❤
Thank you! Cheers!
7:16 I like the 3 bladed fan blades, Sounds like a air conditioner, Build one
i am a big fan of your woke kip it up😁
How does that work?
That´s amazing!! Greetings from Brasil!
go-go gadget pixel reducer
try to use a toroidal propeller it is way more efficient
What camera are you using?
8:19 Why don't the levels fit with the wind speeds?