My grade 9 draft teacher (yes, before CAD, we had draft classes) worked on the Avro project. And one small correction, the craft used three jet turbines, not one. He actually showed original blue prints of the prototype.
Woah! My grandfather worked as a machinist and his retelling of HIS involvement was completely unsatisfying to me! By his story, effectively all workers in his smaller group told to destroy all plans and jigs, etc. All documents erased, employees directed to not speak or acknowledge the project again internally or externally. He was an excellent machinist, but his station in life would not have granted him any knowledge outside of what very small, non-specific parts to mill and then file by hand and to what tolerances. He saw drawings and plans but at best, ONLY the tiny parts of information HE needed to work and not more. Sadly he is not around any more to provide clarification.
I love the way you communicate information, you give us the facts and examples with a little tongue and cheek fluidly. Always gives me a smile... Cheers
I'm a hovercraft (ground effect vehicle) enthusiast. I've always been mystified as to why the flying platform never succeeded. Thank you for this explanation. Please know that ducted fans are extremely popular among hovercraft designers as horizontal thrust fans. They provide a framework for protective screening that prevents fingers or large objects from contacting the propeller blades as well as the superior performance.
Still doesn't explain why a multi-engine design never arose. Rather than trying to redirect the thrust of the lifting fan, why aren't there additional fans mounted at a 90 degree angle solely to produce forward motion? Seems a rather self-evident solution if rotating the engines proves to be a problem...
@@KuraIthys you are still going to have the unbalance to deal with. The first gyrocopters had the same problem.... would accelerate down the runway until takeoff, then lift up and immediately tip over to upside down because of the difference in lift caused by the difference in air speed between the side of the rotor that was advancing and the side that was retreating. Helicopters solved the problem by changing the pitch of the rotor as it went around using a "swash plate", gyrocopters solved it much simpler by simply allowing the rotor blade to "teeter" back and forth so the advancing blade rises as it moves forward then descends as it retreats on the other side of the craft.
I have just gone back to electronics as a hobby after a 51 year break. I was rather shocked to find that any mention of fans for cooling is almost taboo. I like fans. Heat governs the life of an electronic component. However the fans that are used for PC's, power supples and servers etc. are ducted but have large tip clearances, any thing up to 3mm on a 60mm dia fan. It would cost no more to make this gap 1mm. Maybe they should watch your viseos. Thanks for confirming what I had already guessed, it's just logic. I'm subscribing - great channel
Brilliant.!! Thanks for sharing Bruce, It was so interesting, educational and humorous. I look forward to your findings using the ducts on a quadcopter. Keep up the good work..
Thank you very much for this video. This video will be very useful for our model satellite team. If we manage to do it it is basically free stability and thrust.
Great explanation! Plain and simple aerodynamic lesson that explain why elicopters are and will be much better all round flying crafts that multirotors or any ducted fan configurations...
Very interesting video Bruce! I think there might be a similar, although less dramatic effect on bare propellers. Not sure what it is, but if you think of the rotating blades as a disc, the rear blades have air being pushed out towards the blade tip whereas the leading edge of the disc gets air angled in towards the root.
so much budget spending experimenting with this, but they did recoup some r&d when it was directly applied to VTOL craft. thank you for explaining in excellent detail (without math!) how the deign functioned and why it was a fail :)
Super interesting. I wonder if they could have used some sort of air-distruptor fins coordinated with flight attitude to reduce the lift of the lower area thereby allowing it to stay tilted...
The Bell X22, if I recall correctly, resembled a quad with a tail attached to it. Had 4 tilting ducted fans and operated much like the V22 Osprey does today. It was intended to have V/STOL capability but it was much too finicky. It's a shame only two were ever built though, was a beautiful aircraft.
Like in the previous video, invoking the Bernoulli effect only confuses the issue because it's the vehicle that's moving, not the air. The forward edge of the duct is traveling at the exact same speed as the trailing edge. Since there is no air speed differential between the two surfaces, there can be no Bernoulli effect. But there is a difference in the Coanda effect between the two surfaces. As you point out, it's increased on the leading edge and diminished on the trailing edge. In effect, the trailing edge was stalling because of the steep angle of attack. It was designed to attack in an upward direction, not in a forward direction, so unsurprisingly, it fails to perform well going forward. They could probably make it work by adding a small airfoil above the shroud directing air downward into the trailing half of the duct. An airfoil at that position could be adjusted to have the correct angle of attack and compensate for the loss of the Coanda effect. Of course, with the pilot exposed they don't have many opportunities to reduce drag by creating a slipperier vehicle envelope so the speed is always going to be relatively limited. But they should be able to get it to go as fast as a motorcycle.
It will be interesting to see the operation of Blade's Inductrix Quad. They are positioning it as a beginner's quad. It scheduled to come out in the USA in less than 3 weeks.
What would happen in an aircraft where you rotate the ducted fan? When it's upgright, it stabilizes the levitation during vertical take-off and landing. And during flight it stabilizes the aircraft in addition to the wings? Or would it fail during the transition?
One question in parts... what if you are using ducted fans for lift only and a separate thrust device eg small rocket, jet or prop as an example What about a ducted prop for thrust and or a ducted fan for thrust and a ducted fan for lift. I'm only really interested in would it work, and would the complication of mechanical parts an weight make such a system less practical than say a traditional fixed wing set up.
I think they could have used variable geometry lip to manipulate amount of lift generated on any part of the lip and directing the thrust in that fashion
Wow, make a Elec version of that navy duct fan platform using a whole lot of lipo with one big brushless motor. Great for fire dept, Search and rescue, Police, hunters, or recreation. Some time you just need that small jump and leap that ladders or crane can not reach and helicopter are just to big to get into. Like, Two Thumbs up.
Great vid Bruce, and bonus points for mentioning the AVRO flying car! Recommend watching the entertaining made-for-tv CBC movie 'The Arrow' with Dan Ackroyd
Nice presentation Bruce, Thanks heaps! One question though; Did you or anyone ever ty stettin in openable sloths on the duct itself to spoil the effect in the intended direction of travel ?
Perhaps the 1960s was a great time to be in aviation. But I'd argue the current era is just as exciting with far more advanced rapid prototyping and simulation tools now available to every hobbyist.
Can you talk about differences between thrust stand tests and dynamic thrust tests (testing angle of incidence and efficiency) when air is moving past it in operating conditions for quadcopters? People judge a lot on static thrusts stands but certain props dont show the same comparable thrust while flying on a quad. Love your stuff
Hi. How would the coanda lip work on a fully forward thrust propeller such as on a paramotor? Would it be stable in the fully forward position, or would it try to flip me onto my back?
Can you lower the angle of attack on the rear duct to reduce the amount of lift lost? or take the back on off completely and add something else which either negates or complements the lift on the front?
Hi Bruce, what about if you were to cut out the bottom of the duct thus reducing its effect, but leaving the top and the sides to give some lift, but still gaining something from the lack of vortices' ?
I wonder if changing the shape of the lip would change its stability at all. For example, straightening out the lip on one side of the fan would eliminate its lift, causing the fan to tip toward that side.
Hi. Thank you for this very interesting video. It makes me think about turbofans wich are, in my point of view, a mix between a jet engine and a ducted propeler as 80% of the air taken from the intake is not going in the compression chamber but merely propulsed thru an outlet vain and the edge of the turbofan have a shape for generating some coanda effect.
Thank you Professor Bruce, that was very helpful and explains a lot, there is a 4x ducted fan quad on youtube somewhere, i will look and post link if i find it. Cheers,;-)
If you wanted to make the thing go forward as well as up, could you not have a trap-door in the side of the duct and open or partially open it to allow some air to thrust it forward?
Bruce, thanks a lot for your video. It contributed greatly to my understanding of DF Dinamicd. Could you please comment on whether projects on variable coanda lip DF have been completed or are in place?
5 років тому
Interesting what would be the effect of change angle of fan inside the duct.
I’m interested in using ducted fans for generating thrust (not lift) to propel a hovercraft so they would always be at a fixed pitch (perfectly horizontal parallel to the ground). Would I still benefit from this lip design or better to just go fan in tube like in a swamp boat?
It would have been interesting if they had implemented a way to modify parts of the lip. So if the platform was tilting in one direction, then somehow the lop on the opposite side could be changed.
I thought of this too, although in reverse (make the angle/curve of the lip in the direction you are going change to reduce lift on that side). I think that either way the net result is a loss of lift upon changing the shape, creating a need for larger motors. But I sure hope someone is gonna build a drone based on this idea to find out!
I've been thinking about that; but, ultimately I think you would end up reducing your total lift too much. The only solution I can really think of is to change to a different source of lift. So maybe a ducted fan on top of a plane. So you transition to an entirely horizontal flight and use a different lifting surface to maintain altitude.
+Peter Avram Like a helicopter? How about a twin prop, one at the front and one at the back. This would be immune to the effect (as I've explained above) front to back but self stabilizing side to side.
a. The Army also found that the recoil of soldier shooting his weapon (for every reaction there is an equal n opposite reaction) was also a big problem. b. Both the Profile and Parasitic Drag of the hover platform was vary high due to both the frontal surface area of both the duct ring and the pilot standing flat face and body in the slip stream. c. The greater majority of the propeller thrust is use and directed to over come gravity. Almost zero thrust of the propeller's thrust is directed/used for for ward flight on a hover platform. A Drone is able to change it's pitch angle buy adding more thrust on the rear motors. d. Also all airfoils are more efficient when in Ground Effect. Actually 10m is quite good for a wing that is less then 2m in width if I remember correctly. e. Vortex Ring State is when any propeller is stationary thus drastically causes the rotor system to loose it's efficiency/lift. VRS is basically when a propeller is re breathing it's own accelerated air and has killed many a pilot and passenger in helicopters over the decades actually. I think your 3D printed fan ducts may have a good chance on a drone just because of the ability to change the pitch angle by adding more thrust in the rear thus directing some of the thrust to the rear. Good Luck....
I wonder if you had some type of "turkey feather" controls around the lip of the duct where the lip on the low pressure side would be lowered by some type of servo/control rod setup and cancel out the effect to allow it to go faster or would it cancel the vertical lift altogether? Just a thought...
I can understand that making single-fan vehicles difficult (although I'm wondering if some form of slat could deflect some of the ram air away from the downwind side lip). But in a quad, that high lift/low lift discrepancy is going to be repeated four times, on all sides of the CG, not with low lift on one side of the CG and high lift on the other as you have in a single-fan model. There will be a net positive lift on each corner of the craft, and no force imbalance to cause it to pitch up.
So now I am curious what the effect with be of having small aerofoils at the outside of the propeller vanes which would surely reduce the turbulence? Is that the reason some airliners have them ?
Seems to me that the key would be a lip design with a variable geometry. As you tilt to move in a certain direction, the lip adjusts to change how the air flows over the opposing sides and maintains equal lift all around.
Hey Bruce,I was wondering if you could make a video of your DIY 5.8Ghz 200mW video receiver that's in the same stile as the backpack,tell us how much cheaper and comperabile it is as some not so cheap ones ? Also I was wondering if takeing 3 $2 deversity conrolers could you make a 4 input one that will work like the $25 one that you showed us?
Have you done a video where you evaluated a multicopter with motor dihedral? I would like to hear your thoughts on motor dihedral and how it affects stability for slow moving camera platforms. (not fast racing miniquads).
The big one would still get air flowing sideways across the top; because the air was flowing sideways, it would cause it to tilt and counteract the force of the little fan. Only a small tilt of the big fan is needed to counteract the little fan.
"I'm so bad at drawing, I can't even draw the curtains on a cold night".
My grade 9 draft teacher (yes, before CAD, we had draft classes) worked on the Avro project. And one small correction, the craft used three jet turbines, not one. He actually showed original blue prints of the prototype.
Too cool. A Canadian low point that was, F you Diefendumbass. We presently have another PM just like that idiot.
Woah! My grandfather worked as a machinist and his retelling of HIS involvement was completely unsatisfying to me! By his story, effectively all workers in his smaller group told to destroy all plans and jigs, etc. All documents erased, employees directed to not speak or acknowledge the project again internally or externally. He was an excellent machinist, but his station in life would not have granted him any knowledge outside of what very small, non-specific parts to mill and then file by hand and to what tolerances. He saw drawings and plans but at best, ONLY the tiny parts of information HE needed to work and not more. Sadly he is not around any more to provide clarification.
I love the way you communicate information, you give us the facts and examples with a little tongue and cheek fluidly.
Always gives me a smile... Cheers
Thanks for your videos. I appreciate your effort in making them. They are well planned and thought out for easy understanding.
Love your presentations and your personality. You make such complicated subjects so easy to understand.
I'm a hovercraft (ground effect vehicle) enthusiast. I've always been mystified as to why the flying platform never succeeded. Thank you for this explanation.
Please know that ducted fans are extremely popular among hovercraft designers as horizontal thrust fans. They provide a framework for protective screening that prevents fingers or large objects from contacting the propeller blades as well as the superior performance.
Still doesn't explain why a multi-engine design never arose.
Rather than trying to redirect the thrust of the lifting fan, why aren't there additional fans mounted at a 90 degree angle solely to produce forward motion?
Seems a rather self-evident solution if rotating the engines proves to be a problem...
@@KuraIthys you are still going to have the unbalance to deal with. The first gyrocopters had the same problem.... would accelerate down the runway until takeoff, then lift up and immediately tip over to upside down because of the difference in lift caused by the difference in air speed between the side of the rotor that was advancing and the side that was retreating. Helicopters solved the problem by changing the pitch of the rotor as it went around using a "swash plate", gyrocopters solved it much simpler by simply allowing the rotor blade to "teeter" back and forth so the advancing blade rises as it moves forward then descends as it retreats on the other side of the craft.
This is the 4th video of yours I've watched. I LOVE finding great new teachers with YEARS of content just waiting for me :)
Great video Bruce :) Whiteboard videos are awesome and 100X better than school and more informative!
I have just gone back to electronics as a hobby after a 51 year break. I was rather shocked to find that any mention of fans for cooling is almost taboo. I like fans. Heat governs the life of an electronic component. However the fans that are used for PC's, power supples and servers etc. are ducted but have large tip clearances, any thing up to 3mm on a 60mm dia fan. It would cost no more to make this gap 1mm. Maybe they should watch your viseos. Thanks for confirming what I had already guessed, it's just logic. I'm subscribing - great channel
I really appreciate your knowledge and the clear way you share it.
Great job of explaining a complex system in a simple manner. Your graphics are good! Thanks!
Brilliant.!! Thanks for sharing Bruce, It was so interesting, educational and humorous. I look forward to your findings using the ducts on a quadcopter. Keep up the good work..
Thank you so much for those videos and for the time and effort put into them.
Super awesome! Thank you and Best regards from Bavaria!
Perfect. I wanted to make a floating sign that didn't move very fast... Sounds like the self stabling is exactly what I need.
Thank you for sharing your knowledge Bruce!
I guess it shows I'm not the youngest to admit I like your whiteboard videos the most. Thanks for the explanation, Bruce.
Excellent video and explanation.
Thanks for taking the time to do this Bruce. Really interesting.
Love your videos Bruce. Thanks for explaining things in such an easy to understand way.
Bruce, Did you ever record a video of the thrust stand performance of a ducted vs. unducted propeller?
if you are still interested there is a German bloke that did exactly this
@@ferrarikingdom who is he ? Links? IT seems this man did not do it.
@@davemwangi05 ua-cam.com/video/hPUVrRqhyMk/v-deo.html
this guy tried, but didn't get it yet
ua-cam.com/video/QccRbsZVg1Y/v-deo.html
Thank you very much for this video. This video will be very useful for our model satellite team. If we manage to do it it is basically free stability and thrust.
Excellent explanation of these effects on movement on ducted systems. Well done sir.
Great explanation! Plain and simple aerodynamic lesson that explain why elicopters are and will be much better all round flying crafts that multirotors or any ducted fan configurations...
Very interesting video Bruce! I think there might be a similar, although less dramatic effect on bare propellers. Not sure what it is, but if you think of the rotating blades as a disc, the rear blades have air being pushed out towards the blade tip whereas the leading edge of the disc gets air angled in towards the root.
Very important information! Thank you!
Have you done the test of ducted prop thrust vs non ducted prop thrust...very interested in the results.
Nicely explained, thanks Bruce.
so much budget spending experimenting with this, but they did recoup some r&d when it was directly applied to VTOL craft.
thank you for explaining in excellent detail (without math!) how the deign functioned and why it was a fail :)
very informative and easily explained. keep up the good work bruce... just love your videos...
Very interesting bruce,i cant wait to see your video of them in use,i do enjoy your channel
Awesome explation 👌 thxxx mutch 🍀 and lovely greetings from Germany 😘
Thanks for the video! It was very instructional and entertaining.
Super interesting. I wonder if they could have used some sort of air-distruptor fins coordinated with flight attitude to reduce the lift of the lower area thereby allowing it to stay tilted...
Very interesting. Thank you Bruce.
The Bell X22, if I recall correctly, resembled a quad with a tail attached to it. Had 4 tilting ducted fans and operated much like the V22 Osprey does today. It was intended to have V/STOL capability but it was much too finicky. It's a shame only two were ever built though, was a beautiful aircraft.
A good explaiination how ducts work. Thanks for posting!!
You're awesome. Even better than the Discovery chanel. Hope there will be a second video about the antennas.
Thanks for the very helpful explanation!
Nice bit of info and also history stuff =D
Cheers Bruce!
Another great video. I can se this used on larger slow flying video quads.
Like in the previous video, invoking the Bernoulli effect only confuses the issue because it's the vehicle that's moving, not the air. The forward edge of the duct is traveling at the exact same speed as the trailing edge. Since there is no air speed differential between the two surfaces, there can be no Bernoulli effect.
But there is a difference in the Coanda effect between the two surfaces. As you point out, it's increased on the leading edge and diminished on the trailing edge. In effect, the trailing edge was stalling because of the steep angle of attack. It was designed to attack in an upward direction, not in a forward direction, so unsurprisingly, it fails to perform well going forward.
They could probably make it work by adding a small airfoil above the shroud directing air downward into the trailing half of the duct. An airfoil at that position could be adjusted to have the correct angle of attack and compensate for the loss of the Coanda effect. Of course, with the pilot exposed they don't have many opportunities to reduce drag by creating a slipperier vehicle envelope so the speed is always going to be relatively limited. But they should be able to get it to go as fast as a motorcycle.
It will be interesting to see the operation of Blade's Inductrix Quad. They are positioning it as a beginner's quad. It scheduled to come out in the USA in less than 3 weeks.
Very, very informative video. Thanks for the great work!!!
This is awesome yet simple information. Thanks
Thank you so much for the video. I think Mr Tesla figured this out. Let me get back to you on how to make it work.
Absolutely fascinating...Thank you again.
What would happen in an aircraft where you rotate the ducted fan? When it's upgright, it stabilizes the levitation during vertical take-off and landing. And during flight it stabilizes the aircraft in addition to the wings? Or would it fail during the transition?
One question in parts...
what if you are using ducted fans for lift only and a separate thrust device eg small rocket, jet or prop as an example
What about a ducted prop for thrust
and or a ducted fan for thrust and a ducted fan for lift.
I'm only really interested in would it work, and would the complication of mechanical parts an weight make such a system less practical than say a traditional fixed wing set up.
I think they could have used variable geometry lip to manipulate amount of lift generated on any part of the lip and directing the thrust in that fashion
Wow, make a Elec version of that navy duct fan platform using a whole lot of lipo with one big brushless motor. Great for fire dept, Search and rescue, Police, hunters, or recreation. Some time you just need that small jump and leap that ladders or crane can not reach and helicopter are just to big to get into. Like, Two Thumbs up.
Thanks Bruce. I am so curious to see how your ducts work out. Especially on a miniquad
Excellent video my friend!
Another very informative video, Bruce.
Thank you for explaining that. As a young boy I bought a flying model called the flying platform
Thanks for clearing that up! :)
Great vid Bruce, and bonus points for mentioning the AVRO flying car! Recommend watching the entertaining made-for-tv CBC movie 'The Arrow' with Dan Ackroyd
Nice presentation Bruce, Thanks heaps! One question though; Did you or anyone ever ty stettin in openable sloths on the duct itself to spoil the effect in the intended direction of travel ?
I'd love to see a sort of "drone trailer" that used one of these ducts and is simply a pull-behind for a quad that provides a huge battery bank.
Thanks a lot for that Bruce, very interesting.
someone need to do a video compilation on all he times you say "brilliant" in your vids! haha loving the vids mate. very informative
I wonder what would happen if you could vary sections of the lips, profile
that's a basically how a helicopter works
I was thinking of a bunch interconnected metal flaps like the nozzle of a jet engine, but independently controlled
actually I was thinking that maybe have a sort of mesh that slide modified the shape of that round bevel at the rim
Maybe an even riskier design where it would "stall" the coanda effect by protruding flaps to block airflow on one side of the lip.
really nice video, i hope in the future you will make more technical/historical videos of some other topics
What if you had a partially ducted fan? Only have the ducts on the side, for example, leaving forwards and backwards flight unaffected.
Perhaps the 1960s was a great time to be in aviation. But I'd argue the current era is just as exciting with far more advanced rapid prototyping and simulation tools now available to every hobbyist.
Can you talk about differences between thrust stand tests and dynamic thrust tests (testing angle of incidence and efficiency) when air is moving past it in operating conditions for quadcopters? People judge a lot on static thrusts stands but certain props dont show the same comparable thrust while flying on a quad. Love your stuff
Does moving the prop up or down in the duct make a difference?
Rally interesting and inspiring. Thank you! More of the same please!
Another good video, but the one of the problems with the Are Car was it would not hover higher than two feet above the ground.
Hi. How would the coanda lip work on a fully forward thrust propeller such as on a paramotor? Would it be stable in the fully forward position, or would it try to flip me onto my back?
Very, very interesting. Looking forward to see testing results of thoses ducts on a Miniquad =)
Can you lower the angle of attack on the rear duct to reduce the amount of lift lost? or take the back on off completely and add something else which either negates or complements the lift on the front?
Hi Bruce, what about if you were to cut out the bottom of the duct thus reducing its effect, but leaving the top and the sides to give some lift, but still gaining something from the lack of vortices' ?
I wonder if changing the shape of the lip would change its stability at all. For example, straightening out the lip on one side of the fan would eliminate its lift, causing the fan to tip toward that side.
Hi. Thank you for this very interesting video. It makes me think about turbofans wich are, in my point of view, a mix between a jet engine and a ducted propeler as 80% of the air taken from the intake is not going in the compression chamber but merely propulsed thru an outlet vain and the edge of the turbofan have a shape for generating some coanda effect.
Thank you Professor Bruce, that was very helpful and explains a lot, there is a 4x ducted fan quad on youtube somewhere, i will look and post link if i find it. Cheers,;-)
If you wanted to make the thing go forward as well as up, could you not have a trap-door in the side of the duct and open or partially open it to allow some air to thrust it forward?
Its a very kind of you sir, thanks :)
In Winnipeg, we have an Avrocar on display. It is really cool.
Bruce, thanks a lot for your video. It contributed greatly to my understanding of DF Dinamicd. Could you please comment on whether projects on variable coanda lip DF have been completed or are in place?
Interesting what would be the effect of change angle of fan inside the duct.
I’m interested in using ducted fans for generating thrust (not lift) to propel a hovercraft so they would always be at a fixed pitch (perfectly horizontal parallel to the ground). Would I still benefit from this lip design or better to just go fan in tube like in a swamp boat?
It would have been interesting if they had implemented a way to modify parts of the lip. So if the platform was tilting in one direction, then somehow the lop on the opposite side could be changed.
I thought of this too, although in reverse (make the angle/curve of the lip in the direction you are going change to reduce lift on that side). I think that either way the net result is a loss of lift upon changing the shape, creating a need for larger motors. But I sure hope someone is gonna build a drone based on this idea to find out!
That's what I was about to say :D
I've been thinking about that; but, ultimately I think you would end up reducing your total lift too much. The only solution I can really think of is to change to a different source of lift. So maybe a ducted fan on top of a plane. So you transition to an entirely horizontal flight and use a different lifting surface to maintain altitude.
A quad with ducted props should be immune to the effect, as I explained above.
+Peter Avram Like a helicopter? How about a twin prop, one at the front and one at the back. This would be immune to the effect (as I've explained above) front to back but self stabilizing side to side.
a. The Army also found that the recoil of soldier shooting his weapon (for every reaction there is an equal n opposite reaction) was also a big problem.
b. Both the Profile and Parasitic Drag of the hover platform was vary high due to both the frontal surface area of both the duct ring and the pilot standing flat face and body in the slip stream.
c. The greater majority of the propeller thrust is use and directed to over come gravity. Almost zero thrust of the propeller's thrust is directed/used for for ward flight on a hover platform. A Drone is able to change it's pitch angle buy adding more thrust on the rear motors.
d. Also all airfoils are more efficient when in Ground Effect. Actually 10m is quite good for a wing that is less then 2m in width if I remember correctly.
e. Vortex Ring State is when any propeller is stationary thus drastically causes the rotor system to loose it's efficiency/lift. VRS is basically when a propeller is re breathing it's own accelerated air and has killed many a pilot and passenger in helicopters over the decades actually.
I think your 3D printed fan ducts may have a good chance on a drone just because of the ability to change the pitch angle by adding more thrust in the rear thus directing some of the thrust to the rear. Good Luck....
I wonder if you had some type of "turkey feather" controls around the lip of the duct where the lip on the low pressure side would be lowered by some type of servo/control rod setup and cancel out the effect to allow it to go faster or would it cancel the vertical lift altogether? Just a thought...
Would it be possible to alter the shape of the duct to control the coanda effect?
Thanks a lot, Bruce!
Thanks for posting this interesting video.
I can understand that making single-fan vehicles difficult (although I'm wondering if some form of slat could deflect some of the ram air away from the downwind side lip). But in a quad, that high lift/low lift discrepancy is going to be repeated four times, on all sides of the CG, not with low lift on one side of the CG and high lift on the other as you have in a single-fan model. There will be a net positive lift on each corner of the craft, and no force imbalance to cause it to pitch up.
very interesting. a bit of science and history!
Really interested to see how it will perform in practical tests
Hello. Does it make sense to add one propeller perpendicular to the ones that push up ? Will the model go forward while staying flat ?
So now I am curious what the effect with be of having small aerofoils at the outside of the propeller vanes which would surely reduce the turbulence? Is that the reason some airliners have them ?
Interesting video. Do you know how they solved it on the Bell X-22 ?
Seems to me that the key would be a lip design with a variable geometry. As you tilt to move in a certain direction, the lip adjusts to change how the air flows over the opposing sides and maintains equal lift all around.
Hey Bruce,I was wondering if you could make a video of your DIY 5.8Ghz 200mW video receiver that's in the same stile as the backpack,tell us how much cheaper and comperabile it is as some not so cheap ones ? Also I was wondering if takeing 3 $2 deversity conrolers could you make a 4 input one that will work like the $25 one that you showed us?
great info thanks Bruce!
Have you done a video where you evaluated a multicopter with motor dihedral? I would like to hear your thoughts on motor dihedral and how it affects stability for slow moving camera platforms. (not fast racing miniquads).
Sir, what if you placed additional smaller ducted fan positioned horizontally on the platform for forward thrust? Please advise. Thank you! Jon
The big one would still get air flowing sideways across the top; because the air was flowing sideways, it would cause it to tilt and counteract the force of the little fan. Only a small tilt of the big fan is needed to counteract the little fan.
Would the Martin jet pack experience the same issues with stabilisation since it doesn't have the overturned lip? i.e. no area to push up against