Will Electric Jet Ducted Fan Planes Be a Reality in Our Lifetime?

[FredGarvin]

Look up "Project Pluto" for the nuclear propulsion R&D effort.

In terms of electrics, I think the idea will come in some form, some day. There are too many benefits to not chase after them. In part of my company's business, customers would go gaga at the chance for an extremely quiet ride. Of course, a ducted fan would have to be quite a bit larger in diameter to get the roughly the same amount of thrust.
There are hurdles that are on the scale of putting a man on Mars to overcome though. I always wince when I read a paper that the only benefit/output is a "model" to help in the conceptual design of something that can not exist at the current point in time.

 

[mheslep]

Thanks for the response Fred

...
In terms of electrics, ... Of course, a ducted fan would have to be quite a bit larger in diameter to get the roughly the same amount of thrust.

That was my first thought, but then I read that in today's http://en.wikipedia.org/wiki/File:Turbofan3_Unlabelled.gif" engines the majority of thrust already comes just from the bypass, i.e, the majority of propulsion comes from the low pressure compressor fan and not directly via the combustion gasses. Is that true?

Edit: found my source. The Luongo paper claims in existing turbo fans, the fan produces 85% of thrust, jet produces 15% of thrust. Example: GE90 has a BPR of 9:1

 

[FredGarvin]

You're right on that. The fan does produce the majority of the thrust.

 

[mheslep]

Overview of the basic propulsion concept from an earlier Masson, Luongo paper

A. Propulsion
In most modern airliners, propulsion is done through the combustion of jet fuel in turbofans in which, thrust is generated by both exhaust of hot gas and rotation of a large ducted fan generating an airflow bypassing the turbine. In modern engines, most of the thrust comes from the fan and only a fraction, less than 10%, comes form the exhaust. Therefore, it should be possible to replace the turbine by an electric motor and generate the full thrust using a large fan. This concept is presented in Fig. 4.

The duct and fan can be kept almost identical if an electric motor of the same shape and size as the original turbine is designed. The low rotation of the fan being limited to about 2,600 RPM, a propulsion motor will have to exhibit both high power density and high torque density. ...

Figure 14 shows the over all power system, in this case it is based on traditional gas turbines driving generators. A fuel cell system would replace the generator and gas turbine. I posit that a small battery supplement could have large advantages, though the authors don't address batteries. The key given the various new onboard boxes in fig 14 is low weight motors and generators. Superconductor tech. facilitates this, hence this research and the body of the paper.

 

[mheslep]

Powerpoint overview from the authors, better graphics.
http://www.masbret.com/asc08/ASC08_Tuesday_Plenary_Electric_Aircraft.ppt

 

[FredGarvin]

That is all pretty much true. It would be something worth striving for to be sure, but it's not going to happen in our lifetime. This paper reminds me of this cartoon:

http://www.sciencecartoonsplus.com/images/miracle3.gif

If we just get these super conductors...and then if we just get these super batteries...and then we just get these super high powered motors designed...For me, reading papers like that gets old pretty quick. I guess that's why I am in the engineering trenches and not doing pure research.

 

[mheslep]

That is all pretty much true. It would be something worth striving for to be sure, but it's not going to happen in our lifetime. This paper reminds me of this cartoon:

http://www.sciencecartoonsplus.com/images/miracle3.gif

If we just get these super conductors...and then if we just get these super batteries...and then we just get these super high powered motors designed...For me, reading papers like that gets old pretty quick. I guess that's why I am in the engineering trenches and not doing pure research.

I agree with that sentiment when the proposal requires brand new technology with which we have little experience in any field. I observe however, that relatively large jumps ahead occur when incremental developments of mature technologies occur in different fields, then the two merge and enable one another. Electric ducted fans w/ conventional motors have been around in niche applications for years. High power (conventional) electric motors have been in use in locomotive and ship propulsion for years. HTS has been around for twenty years now (and is about to go into a Navy propulsion system). The Air Force Research Laboratory has built and tested a 3MW, 15000RPM, 5.4 kW/kg HTS motor (slide 25 above). Finally the pay offs, as you noted above, are large. If this doesn't happen in my non-chain smoking lifetime then I'd suspect the certification and regulatory process and not the feasibility of the technology.

 

[mheslep]

Airlines now claim they will stop emissions growth by 2020, and do a 50% emissions reduction industry wide by 2050 at the latest climate change spin fest. I don't see how, unless they go electric as discussed here, or get biofuels to work (which does little or nothing about cutting non CO2 emissions NOx, etc ).
http://www.iata.org/pressroom/pr/2009-09-22-01.htm

The aviation industry presented a paper outlining the industry’s commitment to three sequential targets.

1. Improving carbon efficiency with a 1.5% average annual improvement in fuel efficiency to 2020
2. Stabilizing emissions with carbon-neutral growth from 2020
3. Emissions reductions with a 50% absolute cut in emissions by 2050 compared to 2005

 

[mheslep]

An electric X Prize may soon appear, discussed over here:
https://www.physicsforums.com/showpost.php?p=2535479&postcount=1

 

[mheslep]

That is all pretty much true. It would be something worth striving for to be sure, but it's not going to happen in our lifetime. This paper reminds me of this cartoon:

[PLAIN]http://www.sciencecartoonsplus.com/images/miracle3.gif

If we just get these super conductors...and then if we just get these super batteries...and then we just get these super high powered motors designed...For me, reading papers like that gets old pretty quick. I guess that's why I am in the engineering trenches and not doing pure research.

http://www.reliableplant.com/Read/27532/Electric-cars-planes-behind
GE apparently thinks E-Aviation is thirty years out.

[...] Pranav Patel, Chief Marketing Officer at GE Aviation Systems, says electric planes the size of 737s could be flying commercial routes by 2040 or 2045.

In fact, the electric evolution is already underway for conventional planes. “If you look at new jets such as Boeing’s Dreamliner and the Joint Strike Fighter, large portions of their systems are [already] electrified,” Patel says.

The next generation of commercial jets will have “more dynamic power management, allowing essentially a ‘SmartGrid on Aircraft,’ with open rotor types of high-efficiency jet engines,” according to Patel. The eventual goal is “electric propulsion zero-emission aircraft,” which will have an open-structure propulsion — so “when the plane becomes all electric, the motor will still have a propeller-type open-fan structure.”

So just how fast will these electric planes fly? As fast — or faster — than today’s conventional jets. “[Electric planes would be] no different than cars today,” says Patel. “Take the electric car and look at the torque and speed it gives you. It’s actually more torque than you get with a regular [gas-powered] engine.”

Granted, that’s not to say that the Chevy Volt is fully comparable to a 747. “The biggest difference between electric cars and electric planes is you need a significantly higher energy density storage system [for planes],” says Patel. “Weight is very important, because with planes you’re talking about the lift, as well as the range.”

In pursuit of that high density power, engineers who will soon be located at Electrical Power Integrated Systems (EPISCENTER), GE’s new electrical-power R&D center in Dayton, Ohio, are working on aircraft systems that will use solid oxide fuel cell (SOFC) power, with lithium batteries as intermediate storage.

Here is EPISCENTER’s road map to electric commercial flight:

1. Shrink the on-board components of the plane to roughly one-third of their current weight and volume, (via advances in high power semiconductor devices ).

2. Migrate flight control systems away from hydraulic and into electro-mechanical, in order to integrate with electric propulsion systems.

3. Finalize SOFC fuel cell development. Batteries alone don’t have the power density required for long flights — but will remain an important link in the power chain.

4. Optimize high-speed superconducting motors to make the most efficient use of precious on-board power.

So will there someday be 747’s that run like the Chevy Volt? “Sure,” says Patel. “It’s all about energy-optimized aircraft. Some say 50 or 60 years down the road is aggressive, some say maybe not.”

And oh by the way, how about helicopters? “The short answer is Yes.”

I note Dayton is also the location where the https://www.physicsforums.com/showpost.php?p=2292842&postcount=14" was done.