/diy/ here, I am thinking of making a duct for my propeller to get rid of tip vortex losses and for that sweet Coanda lift. The big question was what size to make the duct lip? Is my conclusion in pic related correct? Apparently the size doesn't matter.
Nobody here knows basic algebra?
the real question is why do you write lowercase f like a fucking retard
>>7933022
You knew it was an "f" therefore it is an "f".
>>7933025
Aoccdrnig to rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
>>7933000
no one here can read you.
>>7933029
That's very cool but could you please answer my question?
>>7933101
>coming to /sci/ for actual science/mathematics
wew lad
This board is for shitposting about your degree and arguing about popsci and philosophy
>>7933129
Has it really gotten this bad?
What are you using the propeller for? Is it a generator or something that is flying around?
>>7933178
Drone.
>>7932956
Why wouldn't there be an equal force at the bottom of the duct?
>>7933199
*equal force in the other direction
>>7933199
Because only the top side is curved.
Okay, I would say for the purposes of a drone you are optimizing for least weight and drag, and the thickness of the nacelle doesn't really matter. Pick some standard airfoil to make it out of and focus more on the pressure ratio of the fan and making an efficient nozzle.
>>7933212
>airfoil
Everyone else just bends it over and it works fine. This needs to be simple to manufacture as well.
>>7933229
For some reason I was thinking a fixed wing drone not a quad copter. You're right, for something like that there's no real point in making the outer edge aerodynamic when there is little airflow passing over it.
>>7933029
ayy I remember hearing about this from my psychology friend.
I don't know if it's related, but he also mentioned that it took longer to recognize words by letters
>>7933229
>whole body carbon fiber
How's that stress analysis going?
At my university a couple MEs tried to make a whole drone out of carbon fiber and resin, fucking exploded in mid-air and scared the shit out of the dean of the college.
>>7933273
Also I should mention that carbon fiber bodies in aeronautics is not a solved problem.
Maybe for smaller bodies might be, but for larger bodies (single engine planes) it definitely isn't.
>>7933273
How the fuck could your drone explode? You can literally make a working drone out of four sticks. Sounds like you failed to tighten a bolt or something. Carbon fibre doesn't just pop like that unless you tried making it stupidly thin
Anyway that was a Google image, I plan on 3D printing mine. Weight isn't such a critical issue because this is a big drone. The whole point of this is to test the performance of larger (15" - 18") ducted propellers on multirotors. Never really seen that. If performance sucks I'll investigate ways to improve it.
>>7934090
>this is a big drone
4u
>>7934095
>Basic algebra question
>Most of the replies are memes
What is wrong with this board?
>>7934100
Nice dubs faggot.
Your equations are ideal and the flow is probably neither laminar nor attached. The quick answer is it doesn't matter, the true answer is it is a lot more complex than that.
Your flow is probably turbulent being close to an impeller. The boundary layer of this flow is not attached enough to your lip wall to curve, so it will detach, creating drag.
Ideally, I guess you would be correct, but those conditions won't exist in your case
>>7934132
This is /diy/ work so that's good enough for me. I'm aware that real flows are messy but there is no point in doing computer analysis on a part that doesn't have fine tolerances.
>>7934164
The weight/performance ratio would probably hurt/be negligible. You've cut out a lot of the drag with the tip vortices, I would focus on keeping weight low.
I don't do drones, and I spend more time with wings and dynamics than I do rotocraft, so I could be completely wrong. FWIW, I would reduce the lip angle, and give it more of a trumpet lip. I could see that giving the greatest benefit, and it's easy to do.
