Ducted Fan Pseudo-Jets

[Dan Thomas]

You've pointed out that over 100mph, the increases in drag lower the efficiency of the ducted fan propulsion.

Would you be willing to consider the idea of trying to ionize airflow inside the duct, in order to reduce drag?
Ionized airflow is more laminar than regular air (diatomic gas) and therefore less turbulent with lower drag characteristics.
Please consider that because duct is surrounding the airflow, it provides better opportunities to ionize that airflow.
There are multiple possible methods of ionization: contact ionization, corona discharge, helicon antenna

Ionizing air requires energy, and the energy consumed might be way more than any gains. Engineers have been doing this stuff for decades and they know a lot more than we do.

 

[sanman]

Ionizing air requires energy, and the energy consumed might be way more than any gains. Engineers have been doing this stuff for decades and they know a lot more than we do.

It doesn't require that much energy - at least not compared to running the ducted fans themselves - and the airflow doesn't have to be fully ionized. Just enough has to be ionized, or enough plasma injected into the airflow that it will sufficiently cut down on the drag. The thing is that these engineers are trying to do this for wings -- ie. the outer surface of the aircraft.
Nobody's flying ducted fan pseudo-jets -- they aren't a very common type of aircraft -- so nobody's thought to try the ionization trick for them.

But given the airspeed limitations of ducted fans are particularly due to drag effects, it could be especially worthwhile to try it on them.

 

[Dan Thomas]

It doesn't require that much energy - at least not compared to running the ducted fans themselves - and the airflow doesn't have to be fully ionized. Just enough has to be ionized, or enough plasma injected into the airflow that it will sufficiently cut down on the drag. The thing is that these engineers are trying to do this for wings -- ie. the outer surface of the aircraft.
Nobody's flying ducted fan pseudo-jets -- they aren't a very common type of aircraft -- so nobody's thought to try the ionization trick for them.

But given the airspeed limitations of ducted fans are particularly due to drag effects, it could be especially worthwhile to try it on them.

Ionized air (and plasma) are extremely reactive and might destroy the fan or duct, too.

 

[Tiger Tim]

With regards to ion/plasma augmentation of a power system, it’s probably miles to light years ahead of what this forum is for. Your best bet if you truly believe in it would be to prove it, patent it, and make your millions from there.

 

[henryk]

Ionized air (and plasma) are extremely reactive and might destroy the fan or duct, too.

=electric power [ W=I * U ]...small curent, high voltage =not big power...

-iff=inlet rings=HV electrodes ?

 

[sanman]

Ionized air (and plasma) are extremely reactive and might destroy the fan or duct, too.

Turbines and their ducts also have hot gases flowing through them, but they use suitably resistant materials.
Likewise, it may be that an ionization-augmented fan duct may use some kind of protective coating layer to avoid long term erosion.
Maybe ionization doesn't have to be switched on until sufficiently high airspeeds, where the drag effects become more relevant.

However cold plasmas are not known to be very destructive, and dentists even use them to sterilize parts of a patient's mouth without destroying tissue.
(Just as a ducted fan exhaust can be referred to as a "cold jet", likewise a gas (eg. air) that has ben ionized without being heated can be referred to as a "cold plasma")

With regards to ion/plasma augmentation of a power system, it’s probably miles to light years ahead of what this forum is for. Your best bet if you truly believe in it would be to prove it, patent it, and make your millions from there.

Well, ionized airflow solutions are already being developed to provide drag reduction for the road transportation industry:

I figure that the aircraft industry has to at least keep up with road vehicles.
Aircraft typically travel faster, and drag is more of an issue of concern for them than for road vehicles, which travel slower.

Ducted fans should also be better at noise reduction compared to open propellers/propfans, in addition to being safer. To then make them more fuel efficient through drag reduction could then make them a much more appealing choice for light aircraft.

 

[speedracer]

Turbines and their ducts also have hot gases flowing through them, but they use suitably resistant materials.
Likewise, it may be that an ionization-augmented fan duct may use some kind of protective coating layer to avoid long term erosion.
Maybe ionization doesn't have to be switched on until sufficiently high airspeeds, where the drag effects become more relevant.

However cold plasmas are not known to be very destructive, and dentists even use them to sterilize parts of a patient's mouth without destroying tissue.
(Just as a ducted fan exhaust can be referred to as a "cold jet", likewise a gas (eg. air) that has ben ionized without being heated can be referred to as a "cold plasma")
I've never seen a "successful"ducted fan on a homebuilt, but then, I don't get out much. By successful I mean giving the same or better performance as an UNducted fan (propellor). Can anyone point one out? Thanks.



Well, ionized airflow solutions are already being developed to provide drag reduction for the road transportation industry:

I figure that the aircraft industry has to at least keep up with road vehicles.
Aircraft typically travel faster, and drag is more of an issue of concern for them than for road vehicles, which travel slower.

Ducted fans should also be better at noise reduction compared to open propellers/propfans, in addition to being safer. To then make them more fuel efficient through drag reduction could then make them a much more appealing choice for light aircraft.

 

[sanman]

I've never seen a "successful"ducted fan on a homebuilt, but then, I don't get out much. By successful I mean giving the same or better performance as an UNducted fan (propellor). Can anyone point one out? Thanks.

Check out these two:

 

[henryk]

these two:

-or the third=

"NASA HYBRID"... (200 mpg !)

 

[Malish]

Ducted fans should also be better at noise reduction compared to open propellers/propfans, in addition to being safer. To then make them more fuel efficient through drag reduction could then make them a much more appealing choice for light aircraft.

DF are less noisy then prop and safer on the ground - this is the fact!
And they are good for light aircraft - if someone not planing flying to fast(more than 150mph!), and most GA aircraft and pilots don't fly much faster!

 

[Cardmarc]

Can you reference where to find this book you quoted from? Take a look at this ducted fan intake and fan design and tell me your insights?

Samson Sky | Switchblade Flying Sports Car

Welcome to the future. The Switchblade Flying Sports Car ushers in a new era of high performance personal mobility.

www.samsonsky.com

 

[Malish]

-or the third=

"NASA HYBRID"... (200 mpg !)

Anything can be made to fly faster - but, at what cost? Why to worry about that for light GA aircraft?

 

[Malish]

Can you reference where to find this book you quoted from? Take a look at this ducted fan intake and fan design and tell me your insights?

I(personally) think this car/plane will NEVER fly - remember my words
Or it's may fly - but not very good!
I don't believe in flying cars - to much difference in use(compromises need to be made) and regulations in their use(particularly on the roads).

 

[Toobuilder]

Anything can be made to fly faster - but, at what cost? Why to worry about that for light GA aircraft?

The easy answer is that for some people it is speed that brings utility. More speed means more utility.

But if I was to flip your question around, I might ask: If we only need to go 150 MPH or less, then why even bother designing anything new? I mean, there are HUNDREDS of well proven, existing GA airplanes that fit in this category. Electrics, parafoils, motorgliders, biplanes, RV's, ultralights, spamcans, and classics. Virtually any mission and price range under the sun - why spend the time on "just one more"?

If I only want to go 150 MPH, I pick an airplane and write a check; but if I want to take the speed from 200 knots in cruise to 250, my options are very limited and THAT is going to take some inventing.

 

[henryk]

Anything can be made to fly faster -

"mpg" =mile per gallon,not hauer...?

BTW=circa 90 mph=

 

[BJC]

"mpg" =mile per gallon,not hauer...?

BTW=circa 90 mph=

Wow! Gee! Amazing!

What's that? It doesn't fly?

OK, send me a video when the "flying car" is registered as a car for highway speeds and is certified as an airplane that actually flies.


BJC

 

[Dan Thomas]

OK, send me a video when the "flying car" is registered as a car for highway speeds and is certified as an airplane that actually flies.

And when it's able to accelerate to 90 MPH with the drag of wings on it.

I'm quite sure that a Cessna 150 with the wings off would accelerate a whole lot better than that Switchblade, and a 150's acceleration has never been anywhere near spectacular.

 

[henryk]

Videos about the Switchblade and its production

Take a look at a massive library of videos that share the story of bringing the Switchblade flying sports car to the world.

www.samsonsky.com

=many work...results ?

 

[jedi]

On its third engine instillation IIRC and still has not flown.

 

[henryk]

"flying car" is registered as a car for highway speeds and is certified as an airplane that actually flies.

One moment, please...

in 1949...=

+NEW certyfication methodes/principes.