a beautiful thing God did to human beings, no matter the kind of nerd. good and effective teaching/expression is a kind of art, and good nerds let people see a bit through their eyes.
@Adolph. As soon as I read your comment, I was reminded of the thermostatically operated clutch fans That I've dealt with over the years. I feel dumb for missing that! Excellent observation. 🤔
I've been searching the internet for 3 straight hours to find anything that explains a curved tip propeller. Im working on a project trying to find out how much a curved/warped blade tip would effect the aircrafts performance. Im trying to figure out if this is hurting my drones performance and if so how much and in what way. Thrust? Top Speed, agility? It won't get any worse than this is now. If I dont use the velcro to keep in place the props flop around and snag on thing. Please advise sir I like the way you explain thing. Thanks in advance
Bruce, your enthusiasm to to give information/teach is is wonderfully explained as always in your videos especially to a numb skull like me! you have always given essential and valuable information to the hobbyist and I can vouch for that. I don't usually comment on video's but I felt it was time as I sense that in the last two videos you've posted that your tone is not your usual ' chipper' one ( I sincerely hope I'm wrong). I hope you are able to continue doing what you have been doing which is obviously a passion to you. Thanks again. Joe (UK)
+Alex Curtis I would subscribe to a paid channel by bruce. Even though he operates on a shoestring budget he still produces some of the most informative videos on youtube.
+Joe Musto ...and I thougt Germany was full of restricting regulations and legislation rules. Now I see it´s not. There are strange countries in this world, and they are no "official" dictatorships.
I'm very interspersed in aerodynamics and electronics. By watching your videos, this makes a very good feeling and understanding into me. I want to thank you a lot. And you also talk about efficiency. I'm quite interested in this. Your videos are very effective. And I'm on the way to launch my first project, a rc flying wing. I'm from Bangladesh. Thank you.
Bruce my friend. You've gone and done it again! That was one of the most interesting videos that I have seen for a long while. Your expertise in aerodynamics, RC Quads, RC Fixed Wing, Radio, all collide in this masterpiece. I'll watch it again in a couple of days... :O)
Hi bruce i would like to thank you for what you have done over the years. Your skill and knowledge is like no other. It is still one of my life goals to come and meet you and maybe have a fly. Your channel has been a great part of my life along with many others in this world. I constantly recommend this channel to customers in a hobby shop i work at and will continue to do that. I hope one day this channel can come back as there is no other rc review chanels like it and will never be any like it. Looking forward to a fly thanks Bruce
i had no interest in propellers let alone rc planes. but then this video came along and i found myself interested to the point i now have two planes and am shopping for number three. flying these planes have a feeling of flight and freedom all their own. great way to escape for a bit and it started here. his videos are some of the best out there.
After finding your ducted propeller videos I was wondering about changing a propeller shape, and then saw this! Thanks for your enthusiasm and education! As a pilot I am curious about more advanced design.
First & Foremost Thank You for your dedication, plethura of knowledge, experience and love for "The Hobby". Indeed it is a sad day when entities like MFN'Z can disrupt the joy of the hobby, and crush your ability to provide for your family. In a short time your videos have guided me through building my first multirotor, programming my transmitter, and setting up my Fpv. the RcModelReviews channel has become a second home and I love sharing the channel for individuals who ask about RC or even just want to learn things like soldering. Definitely looking forward to the new reviews and part 2's.... but at the cost of having no more RCModelReciews post Sept. I am heart broken for your situation and the loss of the Yoda of RC. Thanks for all your hard work, effort and passion You've blessed countless souls and hopefully New Zealand can get their act together.
I just wanted to say thank you for the B. S. you have put up with in order to keep this channels content coming, and by the way, I am not a fan of flying, simply an RC enthusiast that can respect good information so I believe your fan base may be more diverse than your aware of, keep up the good fight!
Very clearly explained. I always thought the winglets were supposed to point to the low pressure side to block the airflow around the tip, not to the high pressure side to lead it along, as it were, so thanks for putting me straight!
This is the same why steel nails tip maked without a hook or harpoon ,like an arrow ,to create more stronger bonds between the wood pieces... Thanks for sharing your idea!
Very well explained... it makes us addicted to these amazing propellers facts while convincing me to subscribe here for more! A valuable help to get better inspirations along my workframe around, Thank you!
Bruce! Make RC Model Reviews a paid channel (I know you made a video about this). We all love you and are willing to pay for the contents you provide...
Sir.. Am your fan!! u r awesome.. your videos helped me lot in choosing propellers and increasing my drones efficiency, and much more.. thanks a lottt!!!!!!! Adarsh(India)
liked your video alot. I have seen q-tip props a fair bit while working at my local airport. However, all of the props I saw sloped the tip back towards the fuselage - same direction as the thrust. Whereas you have portrayed them in the opposite direction. Keep up the good work!
Bear in mind that the prop effectively compresses air behind it so a back-tilting fence is going to act to "catch" some of that air. A forward facing one may not be as effective. I suspect the best result would be achieved with something like bidirectional sharklets, but unlike ordinary wings props have a lot of other forces acting on them which need to be taken into account. The kinetic energy in a small GA prop at idle has been described as on par with "a 600mph housebrick - on the end of a piece of string" and that's going to put a lot of streching stress on the length of the blade - As a GA pilot, we were always taught to be extremely careful about nicks on the leading and trailing edges of the props as these could turn into propagating cracks in very short order and the last thing you want when in the air is to have your prop suddenly unbalance itself.
I just found your channel today and watched a couple vids. I am really impressed with them and subscribed right away. Thank you for doing this its awesome i really appreciate all your work and vids its such valuable information
thanks for answering my query. this explains why my tricopter is so much more quiet than the other models as it has the tips on the props. well, that and the slower props speeds.
Props work most efficiently when the tip speed is slightly sub-sonic, so if you have several props on several aircraft, the one with the slower prop (I'm assuming slower in RPM) is also the largest so the tip speed is really the same on all three. Unless one system is not optimised properly and the tip speeds are greatly sub-sonic, but then you got bigger problems than noise...😁
Thanks for another very interesting and educational video. [Everytime I see an autogyro I can't help but think of "Those Magnificent Men in their Flying Machines". To me those "contraptions" look absolutely positively like a "suicide note for an extrovert" ;) ] Best regards.
Hi Bruce just seen your announcement video and can't tell you how pissed off I am for you. I'm only new to your channel and am just in the middle of building my first racing quad following your build videos which are great, as are all the bids I've watched of yours; very informative, interesting and funny. good luck in the future, hope the tide will turn and you'll be back up here on rcmodelreviews again. Regards and best wishes S Edwards
Bruce, you have been one of the greatest online influences in the rc hobby. I just want to say thank you and I really hope this is all figured out. It sounds like that model fly new zeland is a pretty sketchy company. Is there any sort of legal action you could take? Possibly crowd fund this endeavor? We will indeed stick with you Bruce. Good luck and thanks!
I love it! Great explanation, Bruce! I wasn't aware prop winglet like devices were mostly for noise reduction. Good to know :-) I suppose helicopters with these drooping tips on their main rotors are there to mostly reduce noise too. Perhaps even for added stealth.
Sorry you had to pull the plug Bruce! I'm confident I will hear from you in the near future with more entertaining rc video's! Hope you/or someone else, have the time to make a compilation of the best moments of this channel! Thx man!
+xjet Hey Bruce, I found a RC map, if you search for New Zealand you can find a couple places. Just thought you'd be interested in it. www.rcgroups.com/forums/maps.php
Well Bruce for some reason in your bad news vid I cant make or read any comments. Sad news to see such a legends channel go the way it is. Wish there was something we could do. Looks like we wont get to see your 250 quad build or your vortex racing quad. The two I've been waiting for, for so long. I will subscribe to your Xjet channel and see what I think. Good luck Bruce, chin up mate
Is there a way to fit r/c multirotors with props like this? Is there a manufacturer who makes them that small? What would fitting a q-tip prop inside an inductor do?
Really sad that your channel is over. I have looked foward to your video's and will miss you reviewing RTF 250 quads. Its an a shame you have lost your licence to fly but frankly flying on a runway near planes is not a smart move. I wish you all the best in your future adventures sir. gods speed
Currently designing an all electric powered, twin ducted fan powered 2-place aircraft. It is a high wing LSA that will provide a true 90+ minutes of flight time. Both ducted fans will hang from the wings of the aircraft and the. Speeds will be comparable to those found in most traditional 2-place trainers (around 100-knots), and will provide ample room for both the CFI and Student Pilot. Every line will be lifting in its design and very clean....minimal drag! Look very forward to introducing the concept drawings.
I enjoyed your video. You speak well, know your stuff and have a vein of humor. I would love to see your talk on thrust. How would you convince people thrust is not pushing against the atmosphere, but the strongest directional force?
You could, but you'd have to design and fabricate them yourself, since i'm not aware of anyone who makes them in the electric quad size range (3" to 12")
Vegas 666 You are thinking exactly what I was thinking. Quadcopter/drones are so noisy and loud, esp for capturing video. The blade design could be a lot better.
thank you for a clear explanation! would adding strakes and fences midway down the blade reduce air being contributed to the tip vortices at a lower drag penalty?
At the speeds our planes fly, the direction of airflow as far as the propeller is concerned is chord-wise. The cause of the tip vortex is mostly the pressure differential between the "top" and "bottom" of the airfoil. While the drooped tips will not produce "upwards lift" relative to the prop's airfoil (forward thrust to the airplane), they can be designed like airline winglets to produce "forward lift", actually pulling on the prop chord-wise and allowing higher rpm for a given power input.
Sir love the videos. I have a question. What if you put a ball in front of the duct? This would the coriolis effect to suck the air in evenly dispite the angle of the duct. The ball would have to protrude into the duct ending right at the start inpeller blades. The now annular stlye entrace should also speed up the velosity of the in comming air. The ball would seem like an obstruction but only to the force of the air keeping the other side down. The air should theoretically follow the curve of the ball dispite the angle of the duct. Sure youd have to cauculate air flows based on the application but from what i can visualize, the ball should stick out just enough to block the interference from the transition between horizontal and verticle flight. Once in horizontal flight the ball should be spring loaded to push in and funnel more air in from its shock wave, acting like a tunnel ram. This should work. I have some other ideas let me know if youd like to build one?
hello sir,by any chance would you explain about boat propellers, will it works if i use this idea on boat prop, can i use this ducted , qtip or combine this qtip and ducted idea? i know air and water is different mediums.but i would like some input from you if you willing to. anyway thanks for this video, now i know the things i dont before,tq
I believe it would have no positive effect and just increase friction/drag. Possibly much more importantly it would limit to the speed it could rotate as those tips will want to splay out the faster it rotates and that would risk rubbing against the ducting. You could move the tips in to give some room but that makes the ducting less effective.
Good vid. Cheers. Im virtually clueless on the subject bar a few little fun facts but my intuition is leading me to wonder if - wouldn't a significant proportion of the total sound output be due to the leading edge of the propeller 'striking' or travelling through differential pressure zones created in its path by previous propeller(s)? Or wash, or turbulent vortex, or what ever the terminology is for what I'm trying to say lol.
What about banded propellors? Where the band rotates with the blades as opposed to a kort nozzle/ ducted prop. Wanting to try one on my outboard engine to increase fuel efficiency and thrust.
+Alex Curtis Taranis is a great radio I have 1 and never looked back But I also had the Turnigy and that was a great radio ( it did have the Frsky Module )
+Alex Curtis Banggood made a price mistake mate so I wouldn't hold your breath at getting it at all. There probably waiting for you to cancel the order if it hasn't said shipped. They are however supposed to honour the price advertised as it was there mistake. But what should be and what is , isn't always the same. Good luck though.
SeBy DocKy no, it comes from your thrust. The propwash is downward moving air, so when you descend into that, its like climbing a falling ladder. This is also why it makes it worse when you increase thrust. The only way to beat a "vortex of death" or "Vortex ring state" which is it's real name is to fly out of it. In a helicopter you lower your collective and push forward on the stick to dive out of it. Just hope you are high enough to not crash when doing this. I fly full size helicopters btw, I have been in this kind of thing many times in training.
Depends... Could be impulse effects due to the prop being close to an edge like the pusher props on many flying wings make a lot of noise due to this. Could be mach effects if the prop is spinning fast enough. there are a few other things going on, including Doppler effects.
could this be used to make a hoverchair like a wheelchair for disabled with a rubber skirt with chanel's directing the movement with a gyroscope keeping the seat upright at all times
I had thought and posted about curved tip propellers in your first ducted video i didnt know they actually existed. Its really cool to see the theroy of them and why they exist more for noise reasons rather than lift/ thurst. So my next thought is why not make the high pressure side of the propellers have a dimple effect like a golf ball for more aero dynamic properities lets see if you can find a propeller company manafacturing that :P
I've never been so interested in something I don't care about.
Love this guy's passion.
a beautiful thing God did to human beings, no matter the kind of nerd. good and effective teaching/expression is a kind of art, and good nerds let people see a bit through their eyes.
Beyond True!!☺👍✈
I"ve seen these blade tips on a car's radiator fan, now I know its to reduce noise output.
56years old and still learning, thanks Bruce.
Thx dude. I just learned from you too. Good day
@Adolph. As soon as I read your comment, I was reminded of the thermostatically operated clutch fans That I've dealt with over the years. I feel dumb for missing that! Excellent observation. 🤔
I've been searching the internet for 3 straight hours to find anything that explains a curved tip propeller. Im working on a project trying to find out how much a curved/warped blade tip would effect the aircrafts performance. Im trying to figure out if this is hurting my drones performance and if so how much and in what way. Thrust? Top Speed, agility? It won't get any worse than this is now. If I dont use the velcro to keep in place the props flop around and snag on thing. Please advise sir I like the way you explain thing. Thanks in advance
Bruce, your enthusiasm to to give information/teach is is wonderfully explained as always in your videos especially to a numb skull like me! you have always given essential and valuable information to the hobbyist and I can vouch for that. I don't usually comment on video's but I felt it was time as I sense that in the last two videos you've posted that your tone is not your usual ' chipper' one ( I sincerely hope I'm wrong). I hope you are able to continue doing what you have been doing which is obviously a passion to you. Thanks again.
Joe (UK)
+Joe Musto Thanks Joe. Yeah, you're right... the mood is not so high here right now and I'm feeling a bit under the weather.
+Alex Curtis I would subscribe to a paid channel by bruce. Even though he operates on a shoestring budget he still produces some of the most informative videos on youtube.
+Joe Musto Ditto.
If it had not been for Bruce I would never have made my ZMR improved quality arms, he started me building out of carbon.
Good luck Bruce.
+Joe Musto
...and I thougt Germany was full of restricting regulations and legislation rules. Now I see it´s not. There are strange countries in this world, and they are no "official" dictatorships.
I'm very interspersed in aerodynamics and electronics. By watching your videos, this makes a very good feeling and understanding into me. I want to thank you a lot. And you also talk about efficiency. I'm quite interested in this. Your videos are very effective. And I'm on the way to launch my first project, a rc flying wing. I'm from Bangladesh. Thank you.
Bruce my friend. You've gone and done it again!
That was one of the most interesting videos that I have seen for a long while.
Your expertise in aerodynamics, RC Quads, RC Fixed Wing, Radio, all collide in this masterpiece. I'll watch it again in a couple of days... :O)
Hi bruce i would like to thank you for what you have done over the years. Your skill and knowledge is like no other. It is still one of my life goals to come and meet you and maybe have a fly. Your channel has been a great part of my life along with many others in this world. I constantly recommend this channel to customers in a hobby shop i work at and will continue to do that. I hope one day this channel can come back as there is no other rc review chanels like it and will never be any like it.
Looking forward to a fly thanks Bruce
i had no interest in propellers let alone rc planes. but then this video came along and i found myself interested to the point i now have two planes and am shopping for number three. flying these planes have a feeling of flight and freedom all their own. great way to escape for a bit and it started here. his videos are some of the best out there.
Bruce - Very interesting and informative. It's right what they say, "you learn something new every day" - especially after viewing your videos !
Thanks Bruce. This is why I never miss your videos.
What a great education video and the example of the autogyro helicopter at the end. It really is just the engine you mostly hear. That's impressive.
I just watched your latest video, I am really sorry for what has happened. You have helped me a lot with your videos. Thank you for all you have done.
Bruce, you have done it again... A very informative video lesson on aerodynamics with a practical example to boot. Great stuff. Thank you!!!
After finding your ducted propeller videos I was wondering about changing a propeller shape, and then saw this! Thanks for your enthusiasm and education! As a pilot I am curious about more advanced design.
First & Foremost Thank You for your dedication, plethura of knowledge, experience and love for "The Hobby". Indeed it is a sad day when entities like MFN'Z can disrupt the joy of the hobby, and crush your ability to provide for your family. In a short time your videos have guided me through building my first multirotor, programming my transmitter, and setting up my Fpv. the RcModelReviews channel has become a second home and I love sharing the channel for individuals who ask about RC or even just want to learn things like soldering. Definitely looking forward to the new reviews and part 2's.... but at the cost of having no more RCModelReciews post Sept. I am heart broken for your situation and the loss of the Yoda of RC. Thanks for all your hard work, effort and passion You've blessed countless souls and hopefully New Zealand can get their act together.
I just wanted to say thank you for the B. S. you have put up with in order to keep this channels content coming, and by the way, I am not a fan of flying, simply an RC enthusiast that can respect good information so I believe your fan base may be more diverse than your aware of, keep up the good fight!
You consistently explain things very well, thanks.
Informative yet easily understood, as usual. Thanks Bruce!
You're such a good teacher! Keep making these videos, you're one of a kind...
Very clearly explained. I always thought the winglets were supposed to point to the low pressure side to block the airflow around the tip, not to the high pressure side to lead it along, as it were, so thanks for putting me straight!
Once again you made this very easy to understand. Wish I had your ability when i was at university. Thank you.
This is the same why steel nails tip maked without a hook or harpoon ,like an arrow ,to create more stronger bonds between the wood pieces... Thanks for sharing your idea!
Very well explained... it makes us addicted to these amazing propellers facts while convincing me to subscribe here for more! A valuable help to get better inspirations along my workframe around, Thank you!
hi bruce i would like to thank you for what you have done over the years
Bruce! Make RC Model Reviews a paid channel (I know you made a video about this). We all love you and are willing to pay for the contents you provide...
Sir.. Am your fan!! u r awesome.. your videos helped me lot in choosing propellers and increasing my drones efficiency, and much more.. thanks a lottt!!!!!!!
Adarsh(India)
liked your video alot. I have seen q-tip props a fair bit while working at my local airport. However, all of the props I saw sloped the tip back towards the fuselage - same direction as the thrust. Whereas you have portrayed them in the opposite direction. Keep up the good work!
Bear in mind that the prop effectively compresses air behind it so a back-tilting fence is going to act to "catch" some of that air. A forward facing one may not be as effective.
I suspect the best result would be achieved with something like bidirectional sharklets, but unlike ordinary wings props have a lot of other forces acting on them which need to be taken into account.
The kinetic energy in a small GA prop at idle has been described as on par with "a 600mph housebrick - on the end of a piece of string" and that's going to put a lot of streching stress on the length of the blade - As a GA pilot, we were always taught to be extremely careful about nicks on the leading and trailing edges of the props as these could turn into propagating cracks in very short order and the last thing you want when in the air is to have your prop suddenly unbalance itself.
I just found your channel today and watched a couple vids. I am really impressed with them and subscribed right away. Thank you for doing this its awesome i really appreciate all your work and vids its such valuable information
thanks for answering my query. this explains why my tricopter is so much more quiet than the other models as it has the tips on the props. well, that and the slower props speeds.
Props work most efficiently when the tip speed is slightly sub-sonic, so if you have several props on several aircraft, the one with the slower prop (I'm assuming slower in RPM) is also the largest so the tip speed is really the same on all three. Unless one system is not optimised properly and the tip speeds are greatly sub-sonic, but then you got bigger problems than noise...😁
Thanks for another very interesting and educational video.
[Everytime I see an autogyro I can't help but think of "Those Magnificent Men in their Flying Machines". To me those "contraptions" look absolutely positively like a "suicide note for an extrovert" ;) ]
Best regards.
Good explanation. A bit like a science class only now it's interesting while in school it wasnt :-)
Testify
That's why a good teacher can make a big difference
@@94JAVS Yeah, I never hated school for that, everything almost was interesting to me!
Thumbs up for great instructions on ducted fans - oh and the Swanndri jacket, got a coat myself, - Fond memory from my days as a sheep herder
You did a great job as usual. Thanks for all the very informative videos.
Hi Bruce
just seen your announcement video and can't tell you how pissed off I am for you. I'm only new to your channel and am just in the middle of building my first racing quad following your build videos which are great, as are all the bids I've watched of yours; very informative, interesting and funny.
good luck in the future, hope the tide will turn and you'll be back up here on rcmodelreviews again.
Regards and best wishes
S Edwards
Going to miss a wonderful instructor. I am pissed for you as well! Wishing you and the Mrs. a wonderful change in your future!
This is marvellous, I really enjoyed
Bruce, you have been one of the greatest online influences in the rc hobby. I just want to say thank you and I really hope this is all figured out. It sounds like that model fly new zeland is a pretty sketchy company. Is there any sort of legal action you could take? Possibly crowd fund this endeavor? We will indeed stick with you Bruce. Good luck and thanks!
I love it! Great explanation, Bruce! I wasn't aware prop winglet like devices were mostly for noise reduction. Good to know :-)
I suppose helicopters with these drooping tips on their main rotors are there to mostly reduce noise too. Perhaps even for added stealth.
Sorry you had to pull the plug Bruce! I'm confident I will hear from you in the near future with more entertaining rc video's!
Hope you/or someone else, have the time to make a compilation of the best moments of this channel!
Thx man!
This is a great second part to the UHF review. You had some good points on the.. Oh. Nevermind.
+PoppaShocka LOL... there's always one eh? :-)
+xjet Hey Bruce, I found a RC map, if you search for New Zealand you can find a couple places. Just thought you'd be interested in it. www.rcgroups.com/forums/maps.php
+Drew Gardner LOL... kind of fitting that there's nothing at Tokoroa.
***** Haha sorry, There are none around me either!
hey bud, just caught the 'bad' news video. I have found the videos great. I hope things turn around for you. thanks for the effort and time
Really good explanation. Thanks Bruce.
Great analysis !!! 👍🏻👍🏻
Bruce, your videos are great. I use them all the time for teaching. Great Stuff. See you on "Drone and Sundry". -J
Fantastic video, very interesting. Thank you Bruce.
Well Bruce for some reason in your bad news vid I cant make or read any comments. Sad news to see such a legends channel go the way it is. Wish there was something we could do. Looks like we wont get to see your 250 quad build or your vortex racing quad. The two I've been waiting for, for so long. I will subscribe to your Xjet channel and see what I think. Good luck Bruce, chin up mate
Superb stuff ! Thanks Bruce
Is there a way to fit r/c multirotors with props like this? Is there a manufacturer who makes them that small?
What would fitting a q-tip prop inside an inductor do?
Very interesting. Thanks Bruce.
Very enjoyable, thanks Bruce
Good stuff Bruce thanks for the info.
Thank you for teaching us this information. I'd love to be a half Japanese high school girl with you as a English language teacher.
nice one mate
Thanks for the sound of the(912 Rotax)gyrocopter.
That prop is a lot quieter than other ultra lights that I have heard.
Really sad that your channel is over. I have looked foward to your video's and will miss you reviewing RTF 250 quads. Its an a shame you have lost your licence to fly but frankly flying on a runway near planes is not a smart move. I wish you all the best in your future adventures sir. gods speed
Thanks Bruce.
I did not know about "Q" tip props. Thank you.
very well expalined ... Keep up the excellent work
You explained it well.
Always interesting and informative. Thanks!
Really like your white board tutorials Bruce. Hope we get to see more in the future? :-)
Tyu, great video. Wondering why it isnt used in fans, performance is same but noise is reduced.
Currently designing an all electric powered, twin ducted fan powered 2-place aircraft. It is a high wing LSA that will provide a true 90+ minutes of flight time. Both ducted fans will hang from the wings of the aircraft and the. Speeds will be comparable to those found in most traditional 2-place trainers (around 100-knots), and will provide ample room for both the CFI and Student Pilot. Every line will be lifting in its design and very clean....minimal drag! Look very forward to introducing the concept drawings.
I enjoyed your video. You speak well, know your stuff and have a vein of humor. I would love to see your talk on thrust. How would you convince people thrust is not pushing against the atmosphere, but the strongest directional force?
What does q stand for
could i use 4 q-tip propellers to build a quieter quad copter?
You could, but you'd have to design and fabricate them yourself, since i'm not aware of anyone who makes them in the electric quad size range (3" to 12")
Vegas 666 You are thinking exactly what I was thinking. Quadcopter/drones are so noisy and loud, esp for capturing video. The blade design could be a lot better.
wow so these "winged" props would be ideal for park jets using pusher prop set ups?
+m ej I think I'll try to bend tips of an 8x4 gws for my 7x6 pusher
Did it work? I'm considering giving it a try too.
You could also try to use multibladed propellers if noise is the problem.
When geese fly in formation they pick up some of the lift created by the vortex from the bird in front so they expend less energy
Excellent explanation.
keep up the good work . love your work
Thanks B I learned a few interesting things.
thank you for a clear explanation! would adding strakes and fences midway down the blade reduce air being contributed to the tip vortices at a lower drag penalty?
great explanation, thanks.
That’s really interesting, thanks.
Amazing theory
You are a master
Great information
New drinking game, each time this teacher say high pressure or low pressure, take a shot.
Hey thank you. Fantastic explanation.
At the speeds our planes fly, the direction of airflow as far as the propeller is concerned is chord-wise. The cause of the tip vortex is mostly the pressure differential between the "top" and "bottom" of the airfoil.
While the drooped tips will not produce "upwards lift" relative to the prop's airfoil (forward thrust to the airplane), they can be designed like airline winglets to produce "forward lift", actually pulling on the prop chord-wise and allowing higher rpm for a given power input.
Sir love the videos. I have a question. What if you put a ball in front of the duct? This would the coriolis effect to suck the air in evenly dispite the angle of the duct. The ball would have to protrude into the duct ending right at the start inpeller blades. The now annular stlye entrace should also speed up the velosity of the in comming air. The ball would seem like an obstruction but only to the force of the air keeping the other side down. The air should theoretically follow the curve of the ball dispite the angle of the duct. Sure youd have to cauculate air flows based on the application but from what i can visualize, the ball should stick out just enough to block the interference from the transition between horizontal and verticle flight. Once in horizontal flight the ball should be spring loaded to push in and funnel more air in from its shock wave, acting like a tunnel ram. This should work. I have some other ideas let me know if youd like to build one?
Where can I purchase the French propeller?
Thanks
Lee
hello sir,by any chance would you explain about boat propellers, will it works if i use this idea on boat prop, can i use this ducted , qtip or combine this qtip and ducted idea? i know air and water is different mediums.but i would like some input from you if you willing to. anyway thanks for this video, now i know the things i dont before,tq
Excellent ! Thanks
i wonder if resonant frequencies created at specific rpms could be traced and actively cancelled out to reduce noise, too
where can I find TH-cam showing test comparison of ducted propeller to same size not doctored
Robert Mikulec Sr. Here you go! Totally blew my mind how much more thrust he got with the duct. th-cam.com/video/hPUVrRqhyMk/w-d-xo.html
So would adding the wing tips to a ducted propeller make it even quieter and more efficient, or would it have no effect?
I believe it would have no positive effect and just increase friction/drag. Possibly much more importantly it would limit to the speed it could rotate as those tips will want to splay out the faster it rotates and that would risk rubbing against the ducting. You could move the tips in to give some room but that makes the ducting less effective.
My comment on your ducted video one month ago.. about noisyless props.. cheers... :)
Good vid. Cheers. Im virtually clueless on the subject bar a few little fun facts but my intuition is leading me to wonder if - wouldn't a significant proportion of the total sound output be due to the leading edge of the propeller 'striking' or travelling through differential pressure zones created in its path by previous propeller(s)? Or wash, or turbulent vortex, or what ever the terminology is for what I'm trying to say lol.
Great video, thanks!
What was the example of centripetal force?
What about banded propellors? Where the band rotates with the blades as opposed to a kort nozzle/ ducted prop.
Wanting to try one on my outboard engine to increase fuel efficiency and thrust.
Is this related to the bent up wing tips on modern airliners?
Are you going to be doing some entry level quadcopter transmitter reviews?
*****
They cost more than my current 250 quad.
+Alex Curtis Taranis is a great radio I have 1 and never looked back But I also had the Turnigy and that was a great radio ( it did have the Frsky Module )
+Justin Bell I use a Flysky FS-T6. Only cost about £40 here in the UK and I cant fault it. Would like to see bruce do a review on one though :)
+Alex Curtis Perhaps "way back then" you could get a Taranis for that money. Dollar exchange has gone to crap so £150 is probably the best you can do.
+Alex Curtis Banggood made a price mistake mate so I wouldn't hold your breath at getting it at all. There probably waiting for you to cancel the order if it hasn't said shipped. They are however supposed to honour the price advertised as it was there mistake. But what should be and what is , isn't always the same. Good luck though.
how would a propeller react at the wide end of a cone?
Is it not like the propeller twist generates uniform pressure distribution..and thus from the root to the tip there is equal amount of lift generated?
Well done!!
what about a bell shaped loading, where the twist of the blade causes the vortex to be shed inside the tip?
Very interesting .... Maybe it can be used for AP to decreased Vortex effect especially during descend stage avoiding "Vortex of the death " ?
+SeBy DocKy not really, that happens when you descend into your own prop wash. Only way to fix that is to move out of it.
+staslig Yes but it comes mainly by your own created vertexes.... so if you reduced them with such kind of props... it may help
SeBy DocKy no, it comes from your thrust.
The propwash is downward moving air, so when you descend into that, its like climbing a falling ladder.
This is also why it makes it worse when you increase thrust.
The only way to beat a "vortex of death" or "Vortex ring state" which is it's real name is to fly out of it. In a helicopter you lower your collective and push forward on the stick to dive out of it. Just hope you are high enough to not crash when doing this.
I fly full size helicopters btw, I have been in this kind of thing many times in training.
is it true that the thumping sound that a propeller makes is actually the propeller blades sending out shock waves
Depends...
Could be impulse effects due to the prop being close to an edge like the pusher props on many flying wings make a lot of noise due to this.
Could be mach effects if the prop is spinning fast enough.
there are a few other things going on, including Doppler effects.
could this be used to make a hoverchair like a wheelchair for disabled with a rubber skirt with chanel's directing the movement with a gyroscope keeping the seat upright at all times
I had thought and posted about curved tip propellers in your first ducted video i didnt know they actually existed. Its really cool to see the theroy of them and why they exist more for noise reasons rather than lift/ thurst. So my next thought is why not make the high pressure side of the propellers have a dimple effect like a golf ball for more aero dynamic properities lets see if you can find a propeller company manafacturing that :P