More on ducted propeller systems

[@FidoFerrari]

"I'm so bad at drawing, I can't even draw the curtains on a cold night".

[@fredpinczuk7352]

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.

[@minkorrh]

Too cool. A Canadian low point that was, F you Diefendumbass. We presently have another PM just like that idiot.

[@bobert4him]

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.

[@KuraIthys]

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...

[@rosebarnes9625]

@@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.

[@DJDevine]

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

[@jp-um2fr]

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

[@cobracar1]

Thanks for your videos. I appreciate your effort in making them. They are well planned and thought out for easy understanding.

[@harryguy76]

Have you done the test of ducted prop thrust vs non ducted prop thrust...very interested in the results.

[@mickthebass6086]

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..

[@therealgaragegirls]

Love your presentations and your personality. You make such complicated subjects so easy to understand.

[@ColinRichardson]

Perfect. I wanted to make a floating sign that didn't move very fast... Sounds like the self stabling is exactly what I need.

[@TheRCAddict]

Great video Bruce :) Whiteboard videos are awesome and 100X better than school and more informative!

[@farmertony4504]

This is the 4th video of yours I've watched. I LOVE finding great new teachers with YEARS of content just waiting for me :)

[@sunshine7453]

Great job of explaining a complex system in a simple manner. Your graphics are good! Thanks!

[@bgauweiler]

Bruce, Did you ever record a video of the thrust stand performance of a ducted vs. unducted propeller?

[@ferrarikingdom]

if you are still interested there is a German bloke that did exactly this

[@davemwangi05]

@@ferrarikingdom who is he ? Links? IT seems this man did not do it.

[@ferrarikingdom]

@@davemwangi05 kzbin.info/www/bejne/noG4h6WIps2sg80

[@Ritefita]

this guy tried, but didn't get it yet kzbin.info/www/bejne/h5TGg5Wpj7uaZ7s

[@cvetoslavgergov305]

Thank you so much for those videos and for the time and effort put into them.

[@GG7clips]

I guess it shows I'm not the youngest to admit I like your whiteboard videos the most. Thanks for the explanation, Bruce.

[@HiTechDiver]

Excellent video and explanation.

[@analog56x]

Thank you for sharing your knowledge Bruce!

[@Stratobrick]

I really appreciate your knowledge and the clear way you share it.

[@garthfpvtv]

Thanks for taking the time to do this Bruce. Really interesting.

[@ChiliConCarnage]

Love your videos Bruce. Thanks for explaining things in such an easy to understand way.

[@rscofieldfly]

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.

[@willardb123]

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.

[@ficosk8]

Super awesome! Thank you and Best regards from Bavaria!

[@EitriBrokkr]

I wonder what would happen if you could vary sections of the lips, profile

[@crackedemerald4930]

that's a basically how a helicopter works

[@EitriBrokkr]

I was thinking of a bunch interconnected metal flaps like the nozzle of a jet engine, but independently controlled

[@raphaelsilvas2025]

actually I was thinking that maybe have a sort of mesh that slide modified the shape of that round bevel at the rim

[@OmegaF77]

Maybe an even riskier design where it would "stall" the coanda effect by protruding flaps to block airflow on one side of the lip.

[@pauls5745]

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 :)

[@ShotgunAFlyboy]

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.

[@fuyingbro]

Excellent explanation of these effects on movement on ducted systems. Well done sir.

[@GiovanniEsposito5]

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...

[@dinax51]

Nicely explained, thanks Bruce.

[@KraussEMUS1]

Very important information! Thank you!

[@myMotoring]

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

[@mertlale6952]

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.

[@RealCheesyBread]

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.

[@Richardicus881]

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!

[@eggaweb]

That's what I was about to say :D

[@meateaw]

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.

[@GordieGii]

A quad with ducted props should be immune to the effect, as I explained above.

[@GordieGii]

+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.

[@sebastianmort7694]

Absolutely fascinating...Thank you again.

[@GimbalGuy]

Very, very informative video. Thanks for the great work!!!

[@davidriley7659]

It sounds like ducts would be best for stable camera quads used in filming. Also, i wonder if one of these could be used with a vertical propeller for movement, kind of like a PPC

[@Optamizm]

***** This is what I was thinking...

[@sickvic3909]

***** Probably not, airflow is still across duct in one direction tilted or not.

[@owenkilleen]

***** Bruce, do you have an email? I'm going to buy my first quadcopter parts from online, I'd like to run my budget and the list by you. Owen

[@davidriley7659]

owenkilleen I'm not bruce, nor do i care

[@owenkilleen]

***** you tube won't let me post a comment straight in my own comment field. David

[@BobDiaz123]

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.

[@tommee10533]

A good explaiination how ducts work. Thanks for posting!!

[@allant9432]

Very interesting bruce,i cant wait to see your video of them in use,i do enjoy your channel

[@HighFlight2k2]

Very interesting. Thank you Bruce.

[@RC.Aviators]

very informative and easily explained. keep up the good work bruce... just love your videos...

[@dlwatib]

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.

[@sganzerlag]

Thanks for the video! It was very instructional and entertaining.

[@crackedemerald4930]

5:44 "it was too stable" holy Zephyr

[@andybrice2711]

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.

[@ducpao]

Thanks for the very helpful explanation!

[@DrDiff952]

Thanks Bruce. I am so curious to see how your ducts work out. Especially on a miniquad

[@cam_3d]

Nice bit of info and also history stuff =D Cheers Bruce!

[@goriverman]

Thank you for explaining that. As a young boy I bought a flying model called the flying platform

[@qntt2002]

Rally interesting and inspiring. Thank you! More of the same please!

[@Irigoyen4]

Thanks for clearing that up! :)

[@miguelh.m.m.6911]

You're awesome. Even better than the Discovery chanel. Hope there will be a second video about the antennas.

[@DavidDeLuge]

Another very informative video, Bruce.

[@chrisaranega7661]

someone need to do a video compilation on all he times you say "brilliant" in your vids! haha loving the vids mate. very informative

[@jamesthomson1017]

This is awesome yet simple information. Thanks

[@P8qzxnxfP85xZ2H3wDRV]

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?

[@OliFPV]

Awesome explation 👌 thxxx mutch 🍀 and lovely greetings from Germany 😘

[@protovision2010]

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

[@GBLynden]

Excellent video my friend!

[@apocraphontripp4728]

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.

[@dronesovergeorgia2065]

Another great video. I can se this used on larger slow flying video quads.

[@learrus]

Well now I know what shape I am going to be playing with when I build the duct for the electric trolling motor on my boat...

[@Grearson]

Very, very interesting. Looking forward to see testing results of thoses ducts on a Miniquad =)

[@SerafinTirado471]

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.

[@JosephHarner]

What if you had a partially ducted fan? Only have the ducts on the side, for example, leaving forwards and backwards flight unaffected.

[@nickrn85]

Does moving the prop up or down in the duct make a difference?

[@Crlarl]

In Winnipeg, we have an Avrocar on display. It is really cool.

[@meljones7066]

Thanks a lot for that Bruce, very interesting.

[@markd8593]

why they did not add pusher propeller? the platform is horizontal (maximum utilization effectiveness of ducted propeller) and pusher propeller gives speed?

[@deepdivevr7244]

would not work as the air will still rush past the duct perpendicular... even worse than the duct is angled...

[@gilessteve]

Thanks for posting this interesting video.

[@Javiercav]

really nice video, i hope in the future you will make more technical/historical videos of some other topics

[@Kabab]

Cool discretion but I bet it would actually work just fine depending on how sturdy the duct is. The effect would be more of a twist for the arm to resist rather than a force on the craft. Also, if it is a real problem maybe just gradually reduce the lip a little on the front end of the craft. Could still improve efficiency. Lastly, since phantoms usually just hover anyways, wouldn't this make sense for that craft? Putting crash resistance aside.

[@Optamizm]

Thanks for that, Bruce!

[@TheTractorsman]

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,;-)

[@johnjones4638]

what about another set of ducted props to provide the needed forward thrust.

Interesting what would be the effect of change angle of fan inside the duct.

[@Elecifun]

Great video. Does the Parrot AR Drone count ?

[@zachcarrizales5038]

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

[@danielhowsare778]

Really interested to see how it will perform in practical tests

[@steamboatmodel]

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.

[@DJignyte]

Great stuff, cheers for your work!

[@JohnMorley1]

16 mph is four times walking pace. Also, it is able to fly in a straight line whereas a ground vehicle needs to follow the roads.

[@Varue]

John Morley costs a lot more fuel than a land-based vehicle though

[@UTubeGlennAR]

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....

[@legacyfound]

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 ?

[@oscarzt1652]

very interesting. a bit of science and history!

[@budpuppy5657]

Sounds absolutely perfect for a hovercraft

[@andyspoo2]

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?

[@JPinFuerteventura]

Aren't ducted fans used in hovercraft?

[@nathanamorley]

Take a look at the HZ-1 Aerocycle, it preceded the Hiller platform and was very similar except it used a pair of unducted contra rotating rotors that were about 30 ft in diameter. I wonder how the military's experience with the aerocycle differed from the Hiller platform based on what is shown here?

[@SteelsCrow]

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.

[@ThePioneerChannel]

what if they put a second fan to propel it forward? and why didn't they use that technology to create mobile aerial platforms?

[@philbx1]

I'm thinking maybe rotating the 'input airfoil' might have improved this. Anyway, just a thought.

[@garycragg1]

Very interesting video. Thanks Bruce keep them coming. ps how did you crack the left lens in your glasses?

[@witgangyounotube287]

now i can understand why cinewhoops fly so different from normal quads ,i'm now printing fan ducts for my 5" quad

[@chrisb3420]

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...

[@brand0nahue]

hey i was wondering how it might work if the ducts themselves were turned rather than an entire craft?

[@tramsgar]

Thanks a lot, Bruce!

[@Josefppaz]

Hi Bruce interesting I always wonder how they did this with such a high center of Gravity to make this work for the pilot to be on top. What are your thoughts on the Williams X-Jet did they use Gyros for this one or is it the same effect like the platform you are talking about.? cheers for making a video on this

[@MichaelSHartman]

Thanks for the explanation.