"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.

@minkorrh

Жыл бұрын

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

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

4 жыл бұрын

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

3 жыл бұрын

@@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.

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..

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

Thank you for sharing your knowledge Bruce!

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

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

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

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?

@ferrarikingdom

5 жыл бұрын

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

@davemwangi05

5 жыл бұрын

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

@ferrarikingdom

5 жыл бұрын

@@davemwangi05 kzread.info/dash/bejne/moSJuNSLocvffc4.html

@Ritefita

2 жыл бұрын

this guy tried, but didn't get it yet kzread.info/dash/bejne/g5eXtMSsirnNYbw.html

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

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

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

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

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

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

Nicely explained, thanks Bruce.

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

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

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

Super awesome! Thank you and Best regards from Bavaria!

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

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

Excellent video and explanation.

Absolutely fascinating...Thank you again.

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

Thanks for the very helpful explanation!

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

Very important information! Thank you!

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.

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

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

This is awesome yet simple information. Thanks

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 :)

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...

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

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

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

Great stuff, cheers for your work!

Thanks a lot for that Bruce, very interesting.

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

Another very informative video, Bruce.

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

Thanks for clearing that up! :)

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.

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

great info thanks Bruce!

Thanks for posting this interesting video.

5:44 "it was too stable" holy Zephyr

Thanks a lot, Bruce!

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.

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.

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

Thanks for that, Bruce!

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

Thanks for the explanation.

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

@crackedemerald4930

7 жыл бұрын

that's a basically how a helicopter works

@EitriBrokkr

7 жыл бұрын

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

@raphaelsilvas2025

7 жыл бұрын

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

Excellent video my friend!

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

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,;-)

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

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

7 жыл бұрын

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

7 жыл бұрын

That's what I was about to say :D

@meateaw

7 жыл бұрын

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

7 жыл бұрын

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

@GordieGii

7 жыл бұрын

+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.

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.

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?

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.

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

8 жыл бұрын

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

@sickvic3909

8 жыл бұрын

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

@owenkilleen

8 жыл бұрын

***** 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

8 жыл бұрын

owenkilleen I'm not bruce, nor do i care

@owenkilleen

8 жыл бұрын

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

very interesting. a bit of science and history!

very helpful! thanks so much!

Great video! Very educational and easy to understand. Question. What are the effects of a double rotor stack with each rotor turning in opposite directions? With the duct and with out. Thanks!

Its a very kind of you sir, thanks :)

Great video thank you!

Amazing video!

Are you going to review the version 2 of the zmr 250 mini quad frame?

Nice explanation!

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

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.

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

Great video..

Sounds absolutely perfect for a hovercraft

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.

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 ?

Great informative video, thank you Bruce. I was thinking about a successful use of fast, horizontal travel using vertically ducted fans, Hovercraft! Using lateral thrust to propel, they have proven that they can still provide sufficient vertical lift even when enduring horizontal wind forces, I only wonder how much lift they can provide when used in aircraft in the same instance, when a pressure enhancing skirt is not applicable. Will it still provide vertical lift, or will lateral air forces kill lift? If it does however provide lift, then the Martin system may use lateral propulsion?

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

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.

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?

Fascinating!

great job

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?

Hey RCModels huge fan! great Vid! Just wondering whats the point of those knobs in the middle of propellars?!

great video

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?

Good video, thank you.

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

Great video. Does the Parrot AR Drone count ?

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' ?

Interesting video. Do you know how they solved it on the Bell X-22 ?

Great explanation Bruce. Would the Hiller flying platform or a quad be better if you coupled it with a pusher prop?