Ducted fan

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Has anyone attempted to try out a ducted fan system on a drone? I was reading some research on propeller efficiency and the trend appears to be heading towards this system in helicopters and aircraft, it's been around for years with propellers on ships, but to my knowledge never tried on a drone, it should offer better efficiency with no lateral energy waste.
 
I did see an article online with an experimental drone using ducted thrust and it seemed very stable and responsive; if I recall the only issue noted was due to the added complexity there was an increased load on batteries but this was somewhat offset by the increased efficiency of the ducted system. If I can find the article again, I will post a link.
 
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Like all engineering there are trade-offs.

What are the effects on drag during horizontal flight and increased loading in cross-wind hovering?
 
Ducted fan assemblies are significantly heavier than an unshrouded propellor for a given thrust with no efficiency advantage to be realised at lower speeds. Please post a link to the discussion on application to helicopters, I would be interested to read....
 
Notice they've not done anything with it since March 2015. I would guess they've hit the brick wall along the way.
 
I wanted to re-up this thread to see if anyone has experimented with ducted props (not guards) for phantoms, after watching this youtube video.
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I'm curious if ducting would actually improve battery life/ flight time longevity, as is theorized? I have a lightweight snapfit concept that *should* clip onto stock phantom props easily, but I'm not really interested in wasting time or filament to design/ print, if it's already been done with no benefit.

Because I'm not really seeing anything on ducting phantom props, my inclination is that any benefit would be negligible or in fact detrimental to performance. I can't imagine this hasn't been tested and reported on somewhere. Surely DJI or someone would be selling them already if proven beneficial, right?!

I saw these on thingiverse, but nothing for phantom Search Thingiverse - Thingiverse
 
I wanted to re-up this thread to see if anyone has experimented with ducted props (not guards) for phantoms, after watching this youtube video.
To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

I'm curious if ducting would actually improve battery life/ flight time longevity, as is theorized? I have a lightweight snapfit concept that *should* clip onto stock phantom props easily, but I'm not really interested in wasting time or filament to design/ print, if it's already been done with no benefit.

Because I'm not really seeing anything on ducting phantom props, my inclination is that any benefit would be negligible or in fact detrimental to performance. I can't imagine this hasn't been tested and reported on somewhere. Surely DJI or someone would be selling them already if proven beneficial, right?!

I saw these on thingiverse, but nothing for phantom Search Thingiverse - Thingiverse
If the extent of your proposed solution is to fit a shroud to the existing open prop setup on a phantom it will almost certainly be a waste of time. You would need to move the existing mounting arm clear of the airflow (mount to phantom at a point in the perimeter of the shroud), design a new rotor and move to a different motor (higher KV) and ESC. The propulsion system algorithms would require a rewrite. Any efficiency gain that might be realised would be offset by the additional weight and complexity. Not to forget the big difference in thrust outputs the phantom operates over make this solution unsuitable.
 
If the extent of your proposed solution is to fit a shroud to the existing open prop setup on a phantom it will almost certainly be a waste of time. You would need to move the existing mounting arm clear of the airflow (mount to phantom at a point in the perimeter of the shroud), design a new rotor and move to a different motor (higher KV) and ESC. The propulsion system algorithms would require a rewrite. Any efficiency gain that might be realised would be offset by the additional weight and complexity. Not to forget the big difference in thrust outputs the phantom operates over make this solution unsuitable.

Thanks for your response. Very logical conclusions and I find it hard to disagree with any of your points. Certainly not interested in doing most of that! You saved me at least 8 hours of figuring half of this out on my own. This community never fails to deliver.
 
You have two factors that would be against improved performance additional to weight.

1. Ducted fan means you have a significant 'tube' (I'll avoid word Shroud - as that will be used later) that creates a thrust body of air. It would need to be pivoted to assist throttle use to get reasonable movement in desired direction.
2. Intake air would be at angle to the duct even when pivoted causing severe turbulence across the 'mouth'. Any 'lip' compensation for one direction would reduce another.

Shrouded propellers have very shallow depth to the shroud and therefore have far less effect as Duct would ... 1 + 2.

Finally as a regular EDF flyer as well as most types of RC electric and fuel powered - I can honestly say hand on heart that the Ducted Fan 'eats LiPos' faster than any other model I know ... it is actually one of the LEAST efficient propulsion systems we use in RC.

Example : My 50mm EDF T45 hits about 140kph and eats a 1500 4S in about 2.5 mins .... Another exact same model I have with a 4.1 x 4.1 pusher prop on the back end will hit 180kph with about 3 mins on same battery. To get the EDF to get up to speed requires a 5000kv motor ... while the pusher has a 3200kv.
The acceleration of the pusher is far greater than the EDF ...

With regard to the DJI AC's ... I am actually amazed at the flight times we get for our battery packs. Most RC fixed wing will not approach such run times.
 
You have two factors that would be against improved performance additional to weight.

1. Ducted fan means you have a significant 'tube' (I'll avoid word Shroud - as that will be used later) that creates a thrust body of air. It would need to be pivoted to assist throttle use to get reasonable movement in desired direction.
2. Intake air would be at angle to the duct even when pivoted causing severe turbulence across the 'mouth'. Any 'lip' compensation for one direction would reduce another.

Shrouded propellers have very shallow depth to the shroud and therefore have far less effect as Duct would ... 1 + 2.

Finally as a regular EDF flyer as well as most types of RC electric and fuel powered - I can honestly say hand on heart that the Ducted Fan 'eats LiPos' faster than any other model I know ... it is actually one of the LEAST efficient propulsion systems we use in RC.

Example : My 50mm EDF T45 hits about 140kph and eats a 1500 4S in about 2.5 mins .... Another exact same model I have with a 4.1 x 4.1 pusher prop on the back end will hit 180kph with about 3 mins on same battery. To get the EDF to get up to speed requires a 5000kv motor ... while the pusher has a 3200kv.
The acceleration of the pusher is far greater than the EDF ...

With regard to the DJI AC's ... I am actually amazed at the flight times we get for our battery packs. Most RC fixed wing will not approach such run times.

Well said!!

EDF are terribly inefficient. There is a degree of WOW flying a scale EDF aircraft at the field but that's the extent of it IMHO.
 

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