No more propeller

[aviatoreb]

This looks interesting.

https://www.bostonglobe.com/news/science/2018/11/21/send-down-shuttlecraft-scotty-mit-engineers-design-airplane-engine-with-moving-parts/TvXpZmTjZTopEKoY5YRwoM/story.html?p1=Article_Trending_Most_Viewed

[Mooneymite]

I wonder what a gallon of ionic wind will cost?  

[0TreeLemur]

You've intrigued me.   I dove in to see what we are really talking about here.

Here is a video. https://www.youtube.com/watch?v=boB6qu5dcCw&feature=youtu.be

Their aircraft has the mass of a big chicken, with a 3 m wingspan.  The data in the paper show input power of 600W to propel the 2.5 kg craft at about 4 m/s.   That is a specific impulse based on craft mass of 0.0167 s.   My C uses an output shaft power of 95500 W to propel my 1022 kg craft at 72 m/s, a specific impulse based on craft mass of 0.7628 s.   So, my 1967 C is 4500% more efficient at converting energy into mass aloft with forward motion.   So it makes a little noise and burns some smelly 'ol petrol.   Still waiting on lead-free biofuel. 

 

[N201MKTurbo]

Ion engines are only good for spacecraft. They can turn the power from their solar panels into thrust.

they still need a small amount of gas to make them work so they can’t go forever.

In the atmosphear, an electric motor with a propellor is a much better way to turn electricity into thrust.

[DXB]

7 minutes ago, Fred_2O said:

You've intrigued me.   I dove in to see what we are really talking about here.

Here is a video. https://www.youtube.com/watch?v=boB6qu5dcCw&feature=youtu.be

Their aircraft has the mass of a big chicken, with a 3 m wingspan.  The data in the paper show input power of 600W to propel the 2.5 kg craft at about 4 m/s.   That is a specific impulse based on craft mass of 0.0167 s.   My C uses an output shaft power of 95500 W to propel my 1022 kg craft at 72 m/s, a specific impulse based on craft mass of 0.7628 s.   So, my 1967 C is 4500% more efficient at converting energy into mass aloft with forward motion.   So it makes a little noise and burns some smelly 'ol petrol.   Still waiting on lead-free biofuel. 

 

The first combustion engines were pretty crappy too.  I wouldn't count them out yet.

 

[Piloto]

1 hour ago, DXB said:

The first combustion engines were pretty crappy too.  I wouldn't count them out yet.

 

No matter what type of propulsion is used it still takes 1HP to levitate 30 pounds of weight by simple physics math. One problem with Ionic/air propulsion is flying in rain 

[aviatoreb]

1 minute ago, Piloto said:

No matter what type of propulsion is used it still takes 1HP to levitate 30 pounds of weight by simple physics math. One problem with Ionic/air propulsion is flying in rain 

There are LOTs of problems with ionic propulsion.

But very cool.

There are LOTs of problems with piston engines but by golly we been working on them and who woulda thunk that a piston engine full of repeatedly exploding gases would be a good idea.

[Piloto]

7 minutes ago, aviatoreb said:

There are LOTs of problems with ionic propulsion.

But very cool.

There are LOTs of problems with piston engines but by golly we been working on them and who woulda thunk that a piston engine full of repeatedly exploding gases would be a good idea.

Still it requires a power source to drive it. A gas engine put out more power than a solar cell   

[0TreeLemur]

And, as the professor in the video says, the electric field strength is limited by the breakdown of the air. 

What's that smell???   DARPA funds for silent drone research!

[Hank]

These guys come across as pretty arrogant to me, comparing themselves and their indoor model flight favorably against the Wright's outdoor, man-carrying flight. There's a world of difference between a 5 lb. model and full scale, and that doesn't count the weight of the pilot yet. Ask any RC pilot about that . . . .

Is it interesting? Sure. Have they taken the first tiny step? Yes. Are they nearly ready for prime time? Not even close!

[0TreeLemur]

This "discovery" is academic hubris at its best. My point is this: there really isn't much too it, and electric field ionic propulsion isn't practical except maybe for a light weight silent drone flying in a low-wind environment.  Ionic propulsion in the atmosphere is grossly inefficient because it relies on collisions between ions accelerated in an electric field and non-ionized species in the gas to produce thrust.  Some of those collisions accelerate air in directions that don't contribute to the direction of thrust!   The ion acceleration is limited by the electrical breakdown of air that decreases with altitude.  If they were testing it with a higher field strength at takeoff, their electric field would break down the air and create an arc.  Ever seen an ionic fan for sale?   Nope.  At higher field strengths below breakdown the ions can create NOx and O3, both of which are not particularly good for your health.

Read this for grins & giggles and you'll see what I mean: http://www.airpurifierguide.org/faq/what-happened-to-ionic-breeze

[aviatoreb]

5 hours ago, Fred_2O said:

This "discovery" is academic hubris at its best.

Your points are all well said and spot on.  I agree.

Still I find it to be interesting.   I do not think this will ever be relevant for flying airplanes with people in it around.  Or even drones the size we are used to seeing.  I could imagine mite-sized drones flying this way.  Drones the size of dust up to drones the sized of gnats.  

[yvesg]

Here is some propless, jetless modern propulsion technology:

https://en.m.wikipedia.org/wiki/Bob_Lazar

Yves

[Hank]

1 hour ago, aviatoreb said:

Still I find it to be interesting.   I do not think this will ever be relevant for flying airplanes with people in it around.  Or even drones the size we are used to seeing.  I could imagine mite-sized drones flying this way.  Drones the size of dust up to drones the sized of gnats.  

Indoors.

[aviatoreb]

1 hour ago, Hank said:

Indoors.

You bet.

Imagine environmental sensing drones whipping about in big buildings sensing all sorts of environmental factors.  Or even finding and cleaning out small environmental hazards like germs or toxic aerosols.

Imagine secret agent drones whisping about in places where there are secrets to be learned.

[Hank]

15 minutes ago, aviatoreb said:

Imagine secret agent drones whisping about in places where there are secrets to be learned.

. . . and dispensing various aerosols . . . Thanks for the nightmares! 

[N201MKTurbo]

Be careful what you wish for.

[gsxrpilot]

As someone who makes a living on the cutting edge of technology, the one thing I do see in common with the Wright brothers and their flyer... are all the naysayers standing around saying what a waste of time and effort.

[Cyril Gibb]

On 11/23/2018 at 10:44 PM, Piloto said:

No matter what type of propulsion is used it still takes 1HP to levitate 30 pounds of weight by simple physics math...

There are many many definitions of horsepower.  Nevertheless you've missed the time component. I think that in the case of mechanical horsepower, it's the ability to lift 550 lbs 1 foot in 1 second.

[Piloto]

21 hours ago, Cyril Gibb said:

There are many many definitions of horsepower.  Nevertheless you've missed the time component. I think that in the case of mechanical horsepower, it's the ability to lift 550 lbs 1 foot in 1 second.

HP is a definition of power equivalent to 746 watts. 550 lbs/foot/1 second is an energy rate or power. This why constant power is required against a g acceleration levitation. Energy alone will only kick you to a certain height but power is required to maintain that levitation height.

José

Edited November 26, 2018 by Piloto

[aviatoreb]

3 hours ago, Piloto said:

HP is a definition of power equivalent to 746 watts. 550 lbs/foot/1 second is an energy rate or power. This why constant power is required against a g acceleration levitation. Energy alone will only kick you to a certain height but power is required to maintain that levitation height.

José

Forget about units for a sec.  let’s talk physics.

energy is Force exterted over a distance.  E=Force times distance.

power  is energy spent in a time duration. Power=energy/time = Force Times distance/time = Force Times velocity.

[Hank]

12 minutes ago, aviatoreb said:

Forget about units for a sec.  let’s talk physics.

energy is Force exterted over a distance.  E=Force times distance.

power  is energy spent in a time duration. Power=energy/time = Force Times distance/time = Force Times velocity.

What causes grief for many people calculating in Standard units is that lb_m =/= lb_f. That's where slugs come in. It was all very confusing in college during the Reagan years, but Wikipedia sure makes it seem easy now! But then again, I'm reading quietly at home for pleasure, not struggling with homework or final exams any more. Memory, not wiki, says something like 32.2 ft•lb_ff/lb_m•sec², although I may have pound-mass and -force backwards.

[Piloto]

Just to put it in simple terms a Mooney will not sustain altitude unless the engine develops power. Using the ratio that a HP can lift 30 pounds makes sense on a Mooney since a 200hp engine running at 50% power (100HP) can lift a 3,000 pounds plane. Excess power is used to overcome airframe drag. This power to weight ratio is known since the Wright Brothers 1903

José 

[carusoam]

The power of MS...

One minute we are learning about cognitive dissonance...

The next, the inner workings of actual laws of physics...

Earlier Somebody mentioned... intellectually thinking...

Then there were discussions of viscosity and synthetic chemistry...

 

Now we are learning what makes 10% more hp worth a lot of AMUs...  would you like a decoder ring with that?

We can suspend a significant amount of weight in the plane, Take-off in shorter distances, and climb like a crazy home-sick angel... before cruising quickly in the FLs... while measuring dissolved O2 in our blood stream...

PV=nRT for the turbo guys... flying in the FLs takes a compressor to do it well... and an intercooler for staying out of the red box, and avoid pre-ignition challenges...add a pressure controller for best, long lasting, performances...

Chemistry, biology, Transport phenomena/heat transfer, physics/mechanics, machine design theory...

Anyone ever say ‘I want to fly a plane, I will become a scientist’ when they were young?

Today the kids want to learn STEM to forward their dreams....   with a Mooney, they have come to the right place!

 

MS, a place where intellectual pilots hang out between flights... 

Best regards,

-a-

[Jim Peace]

The weakest force in the universe is gravity and we really do not know what it is. And we spend hundreds of thousands of dollars in our hobby trying to defy it. 

Really no point in what I wrote. I was actually just laying in bed trying to figure out how everything I thought I knew about the orbits of electrons is wrong. There is no orbit and they now can sometimes theoretically visit the nucleus. 

Time to go burn some avgas.