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Ion drive for aircraft imminent.



 
 
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  #121  
Old December 7th 16, 05:27 PM posted to sci.space.policy
David Spain
external usenet poster
 
Posts: 2,901
Default Ion drive for aircraft imminent.

On 12/6/2016 7:31 PM, Fred J. McCall wrote:
David Spain wrote:


I'm not taking sides, just seems like a practical suggestion. Also web
blogs are more versatile: text, graphics, videos all are fair game there
and you can control the topics, create a better presentation and engage
with those who share your views. OK an echo chamber perhaps. But better
than the endless shouting matches here.


The problem is that Mookie thinks the purpose of Usenet NEWS is to
allow him to 'blog'.



Not much of a blog when it has been plonked.

Dave

  #122  
Old December 9th 16, 01:03 AM posted to sci.space.policy
William Mook[_2_]
external usenet poster
 
Posts: 3,840
Default Ion drive for aircraft imminent.

On Wednesday, December 7, 2016 at 6:45:11 AM UTC+13, David Spain wrote:
On 12/6/2016 9:15 AM, Jeff Findley wrote:
In article ,
says...

I often play cool music when flying over New Zealand.


All these have appropriate and moving musical scores... sensitive people hear it. Others, not so much.


This isn't your personal blog Mook. This is "sci.space.policy", a
Usenet Newsgroup.


Good point. Mr. Mook why don't you create a blog and although OT post a
link to it here so that those that want to follow you can? No one can
stop you from posting a link. They can bitch but the link will be here.

Then you don't have to put up or waste time with critiques you don't
want to read from people you obviously do not respect and vice-versa.

I'm not taking sides, just seems like a practical suggestion. Also web
blogs are more versatile: text, graphics, videos all are fair game there
and you can control the topics, create a better presentation and engage
with those who share your views. OK an echo chamber perhaps. But better
than the endless shouting matches here.

Dave


Your comments would make more sense David, if you directed it at those who are shouting the loudest. lol.
  #123  
Old December 9th 16, 01:04 AM posted to sci.space.policy
William Mook[_2_]
external usenet poster
 
Posts: 3,840
Default Ion drive for aircraft imminent.

On Thursday, December 8, 2016 at 5:27:42 AM UTC+13, David Spain wrote:
On 12/6/2016 7:31 PM, Fred J. McCall wrote:
David Spain wrote:


I'm not taking sides, just seems like a practical suggestion. Also web
blogs are more versatile: text, graphics, videos all are fair game there
and you can control the topics, create a better presentation and engage
with those who share your views. OK an echo chamber perhaps. But better
than the endless shouting matches here.


The problem is that Mookie thinks the purpose of Usenet NEWS is to
allow him to 'blog'.



Not much of a blog when it has been plonked.

Dave


Ion drive requires an electrical source. This naturally for any thinking person brings up electric aircraft which have been flown. Some have been powered by batteries. Others powered by beamed energy. This is obviously an emerging trend, and will continue to be an important development going forward.

  #124  
Old December 9th 16, 02:31 AM posted to sci.space.policy
William Mook[_2_]
external usenet poster
 
Posts: 3,840
Default Ion drive for aircraft imminent.

A big issue for any electrically powered aircraft is the power to weight of the drive train. Some huge advances have been taking place in this area. 10 kW per kg for electric motors have been announced by Emrax.

http://www.nextbigfuture.com/2015/04...-power-to.html

SImilar advances have been announced for other parts of the drive train. 3 kWh/kg for example, appear to be in store.

Using atmospheric oxygen and stored liquid hydrogen we can get

If hydrogen fuel cells

Ballard Power Systems Xcellsis HY-205 205 kW PEMFC
2,170 kg 94.5 W/kg Mercedes-Benz Citaro O530BZ

UTC Power/NASA 12 kW AFC
122 kg 98 W/kg Space Shuttle orbiter

Ballard Power Systems FCgen-1030 1.2 kW CHP PEMFC
12 kg 100 W/kg Residential cogeneration

I used this one in an application in Southeastern Ohio back in the day;

https://web.archive.org/web/20160325.../PV/index.html


Ballard Power Systems FCvelocity-HD6 150 kW PEMFC
400 kg 375 W/kg Bus and heavy duty

NASA Glenn Research Center 50 W SOFC
0.071 kg 700 W/kg

Honda 2003 43 kW FC Stack PEMFC
43 kg 1000 W/kg Honda FCX Clarity

Lynntech, Inc. PEMFC lab prototype
0.347 kg 1,500 W/kg

We're headed in the right direction! But, we're still way below where we need to be in order to have fuel cells compete with other power plants.

BMW i4 1.490L M12 engine 1987 gas (petrol) Otto engine
1030 kW 1,400 hp 8.25 kW/kg 5.07 hp/lb
Arrows A10 ca], Formula One auto racing

GE90-115B Brayton turbofan jet engine
83,164 kW 111,526 hp 10.0 kW/kg 6.10 hp/lb
Boeing 777

PWR RS-24 (SSME) Block II H2 Brayton turbopump
63,384 kW 85,000 hp 138 kW/kg 84 hp/lb
Space Shuttle (STS-110 and later)

PWR RS-24 (SSME) Block I H2 Brayton turbopump
53,690 kW 72,000 hp 153 kW/kg 93 hp/lb
Space Shuttle

If we reach 2 kW/kg we're in the radial engine range! lol.

Wright R-3350 54.57 L 18-c s/c Turbo-compound Radial engine
2,535 kW 3,400 hp 2.09 kW/kg 1.27 hp/lb
B-29 Superfortress, Douglas DC-7
C-97 S/f prototype, Kaiser-Frazer C-119F

However, research at major national labs suggests that micro-scale (MEMS based) fuel cell technology provides a clear path to attain 10 kW/kg to 100 kW/kg range with these electrical sources!

https://techportal.eere.energy.gov/t....do/techID=487

With hydrogen and 60% conversion efficiency (assuming no use of the thermal energy) to 80% conversion efficiency (assuming thermal energy is captured in the exhaust stream and adds to thrust) - we can see that hydrogen fuel can provide 23.6 kWh/kg to 31.5 kWh/kg - which is roughly 10x greater than the 3 kWh/kg likely to be achieved soon in the best batteries!

https://en.wikipedia.org/wiki/Cobalt_Co50_Valkyrie

The Cobalt Valkyrie has a 260 kW (350 hp) engine that masses 285 kg with turbo-charger. The aircraft carries 109 gallons (410 litres) of AV-gas. That's 300 kg of fuel. A total drive train weight of 585 kg. for a 1,550 kg take of weight carrying four passengers and luggage.

Now flight duration under economy cruise is 5.74 hours and 109 US gallons of av fuel contain 3,758.3 kWh of thermal energy. The engine converts 1,491..4 kWh to mechanical energy over this period giving the engine a 39.7% overall mechanical efficiency.

An electric motor that masses 26 kg and produces 260 kW replaces the thermal engine and 3 kWh/kg provides 1,677 kWh of electrical energy which is converted to 1,593.2 kWh with a 95% conversion efficiency.

So battery airplanes are nearly ready for general aviation use! Ionic thrusters if they can be made to work at comparable power densities to electric motors would cause them to replace electric fans.

Fuel cells at 1.5 kW per kg would weigh 173.3 kg and leave 385.7 kg of hydrogen fuel (and tankage). With a 20% structure fraction for the tank, a zero boil off tank would carry 308.56 kg of liquid hydrogen. It would also occupy 4,408 litres of volume! About 10x the volume of av-gas! But even at the lower efficiency figure of 60% - we have 7,282.0 kWh of mechanical energy available from this drive train - which gives the aircraft 4.882x the range - or 12,968.3 km!! Over 1/4 the way around the world in about 28 hours! A true global explorer!

With AI guidance and controls, passenger drone operation is possible, and people can sleep and relax on board.
  #125  
Old December 9th 16, 03:47 AM posted to sci.space.policy
William Mook[_2_]
external usenet poster
 
Posts: 3,840
Default Ion drive for aircraft imminent.

4408 litres of volume for LH2 might seem a killer, but when one considers that the volume of a Continental six cylinder engine (TSIOF-550-D) occupies

http://www.continentalmotors.aero/up...ies_032012.pdf

43 inches x 43 inches x 64 inches - a total volume of 1,940 litres. Adding 410 litres to this volume we have 2,350 litres - more than half the required 4,408 to carry all the hydrogen the weight chart indicated previously.

This volume is just for the engine block as shown. When one counts the 410 litres for the av-gas along with the intake and exhaust volumes in the airframe of the Valkyrie, we can easily find 4,408 litres of hydrogen tank volume along with the volume needed for the compact electric motor.



  #126  
Old December 10th 16, 12:24 AM posted to sci.space.policy
William Mook[_2_]
external usenet poster
 
Posts: 3,840
Default Ion drive for aircraft imminent.

NASA has outlined MEMS based micro-thrusters in its technology roadmap, including ion engines.

https://www.nasa.gov/pdf/501329main_...-Nov2010-A.pdf

An ion engine that uses the air, along with electrical power either stored on board or beamed, that can switch to inert stored propellant, when the atmosphere is no longer available, would be ideally suited for a single stage to orbit spacecraft.

With a 9.8 km/sec exhaust speed a SSTO using air through 1.2 km/sec must carry sufficient propellant to impart 8.0 km/sec. This implies a 55.8% propellant fraction. A kg of propellant moving at 9.8 km/sec contains 48.02 megajoules per kg means that you need 16.7 milligrams of nuclear isomer batteries per kg of inert propellant.

http://bit.ly/2gu11jm

https://str.llnl.gov/str/JulAug05/pdfs/07_05.4.pdf

http://matus1976.com/features/isomer.htm

You need 0.001 kg/sec propellant flow rate per kgf of thrust and 48.1 kW of power. A laser beam could also replace a nuclear isomer power source.

http://www.navalreview.ca/2012/05/wh...on-ship-carry/

A 10,000 ton payload with a 6% structure fraction implies a 24,875 ton take off weight, 995 ton structure, 12,880 tons of sea water. 214.8 kilograms of nuclear isomer batteries are required to power this thing. 2.4 trillion watts are required to lift it with beamed energy. 8 grams of Lithium-6 Deuteride could also generate sufficient energy to energise the 12,880 tons of propellant.
 




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