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Electric Jet Ducted Fan?

by violin_writer
Tags: ducted, electric
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violin_writer
#1
Feb7-09, 01:31 AM
P: 21
I have planed to make a small engine for my RC. I plane to use clay and (balsa layers) wood for structural support. I know clay is relatively heavy, so I only plan to use I tiny amount for the wind tunnel of the plane.

Like one other person had mention, I want to use a "cold" jet. I plan on spacing the fan blades apart and using a reverse nozzle to compress/focus the air and they use the rocket nozzle on the other side. Over all, air way should short.

What's even more wacky, is that I plan to do this with electric power... and I hope it will outlast all other Fan Duct planes. For electricity, I plan to use a combo of LiIon batts and Solar panels.

Am I far fetched? If you think not, then please help... I would like have some websites or something to look at. Thankyou

PS: I give you permission to laugh if ya want.
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kach22i
#2
Feb7-09, 04:33 AM
P: 164
I don't think your ideas are wacky, I also have a concept for an "electric cold jet".

In lieu of clay please consider going to your local ACE Hardware store and spend some money on some West Systems Marine Epoxy, micro balloon fillers, graphite additives, fiberglass cloth and throw in some rigid insulation (extruded not bead board/expanded).

The above suggestion is a very expensive one, one you may do later for a larger scale or full sized project.

I think that you will find that bass wood and balsa wood are easily sculpted with course sand paper and razor blades (or small saws). Add some dope to seal it up and look like a pro.

I have not use automotive plastic body filler (Bondo) with wood, I don't think you will get a good bond, so don't bother.
violin_writer
#3
Feb7-09, 04:29 PM
P: 21
Thanks--- how's your idea coming along.
You don't have tell me exactly what you did, I just want to know if you've made any process. Do you have a working model?

kach22i
#4
Feb7-09, 07:19 PM
P: 164
Electric Jet Ducted Fan?

Quote Quote by violin_writer View Post
Do you have a working model?
I have a hovercraft model project which is about 75% done, been that way for nine months just sitting until I have the time and money to fit it all together. Even at 1" = 1'-0" scale, I don't expect the 50 inch long model to prove or disprove any of the inlet air feed questions I have. Some things just don't "scale" right and I think this is one of those things.
violin_writer
#5
Feb7-09, 10:12 PM
P: 21
I see... the root of all canceled or held experiments--- money.

Me I don't, and probably wont ever have the money to have a full scale model built (I'm terrified of heights so I'll probably never fly it). I am what you would call horribly poor. So, instead of having a $100,000 or so full-scale model, it'll be probably $200-300. I will work with what I can find without confrontation, anything to do with specific manufacturing of things. So, this plane with going to be hand made with everyday materials--- run of the mill DC motor.

I think the main problem with "cold" jet theory, is drag in the wind tunnel-- so, I think I'm going to come with a strange looking RC plane. Oh yeah, my engine system is neither "hot" nor "cold", I call it warm. I want to use 6v or 12v to heat a washer create heat at the end of the nozzle if possible.

I'm at 5% of my project. I know what materials to use, what engine. I just don't know how to configure that engine. I don't want to use two, but I do want to use 2 props.---- I'm starting to get a headache
Cyrus
#6
Feb7-09, 10:45 PM
Cyrus's Avatar
P: 4,777
I'm not sure what you mean by your explanation. For what it's worth, I'm currently building a wind tunnel model for this aircraft to be tested next week:



The model is made from Wind Tunnel Model foam in a CNC machine:







You can very well make your own wind tunnel at home. I've done it using a leaf blower and plexiglass! The leaf blower will be loud as hell, but you will get a nice, fast, jet of air. Playing around with different configurations is fun, but make sure you have some references so that you can actually learn as you experiment. :)
kach22i
#7
Feb8-09, 10:53 AM
P: 164
Cool an Osprey V22 like-ish UAV.

Awesome.

I've been told that if I want funding for any of my dream projects that I have to make it a UAV proposal.

I want those fans, how much?

Full circle, hey?
http://diydrones.com/photo/photo/sho...APhoto%3A27287


American Dynamics AD-150
http://www.americandynamics.us/News.shtml



E-Bay model Item number: 220353832572 ($138 static wood model)
violin_writer
#8
Feb8-09, 12:30 PM
P: 21
I'm not sure what you mean by your explanation.
--- I read it over and I agree... lol! Never would have thought of that though, a wind tunnel with plexiglass and a leaf blower.

I didn't mean "wind tunnel", wind tunnel. sorry. I meant the duct around the fan. I think the "drag" or "lack of efficiency" comes from air intake. It's because the air is hitting the fan faster and faster as the plane increases speed; because the fan is getting air faster that it can suck-in. That's probably why the previous "cold jet models" haven't worked.
---But that is just me, I'm just 19, and haven't a clue in aeronautics.

By the way, that is one sweet plane!!! I wonder what the air intake on the bottom is for?
I like you're workspace too...:)
violin_writer
#9
Feb8-09, 12:48 PM
P: 21
I'm not sure what you mean by your explanation.
--- I read it over and I agree... lol! Never would have thought of that though, a wind tunnel with plexiglass and a leaf blower.

I didn't mean "wind tunnel", wind tunnel. sorry. I meant the duct around the fan. I think the "drag" or "lack of efficiency" comes from air intake. It's because the air is hitting the fan faster and faster as the plane increases speed; because the fan is getting air faster that it can suck-in. That's probably why the previous "cold jet models" haven't worked.
---But that is just me, I'm just 19, and haven't a clue in aeronautics.

By the way, that is one sweet plane!!!
I like you're workspace too...:)
aquitaine
#10
Feb8-09, 07:23 PM
P: 200
I have planed to make a small engine for my RC. I plane to use clay and (balsa layers) wood for structural support.

I would think making it out of plastic would be better, it will hold together better and (maybe) save some weight.
Cyrus
#11
Feb8-09, 08:41 PM
Cyrus's Avatar
P: 4,777
You are going to have a tough time getting plastic to come out lighter than balsa wood. I would not recommend it!
violin_writer
#12
Feb11-09, 06:16 PM
P: 21
I did some reading... and decided to make a system of nozzles throughout the RC ducted fan system. I figured I would use a small intake, to vacuum in air at a high rate of speed. Then, I would create an internal nozzle, compress the vacuumed air by ramming it. The fan that vacuums the air would increase the air speed, the propeller would work just like a normal ducted fan by slowing it down and compressing it. Then, the compressed air would go out of the last nozzle just like a rocket.--- I'm not to confident about it because I'm the one who came up with it.

Could someone tell me what they thought?

F.Y.I.- It turns out I'm going to have some parts custom made so I'm going to have to use some plastic, wood, and then clay for insulation for the "heated nozzle" I'm also planning to use.
Cyrus
#13
Feb11-09, 06:20 PM
Cyrus's Avatar
P: 4,777
I would encourage you to make an engineering drawing.
mheslep
#14
Jul31-09, 05:30 PM
PF Gold
P: 3,098
Anybody familiar with the just released FSU electric turbo fan research by Masson and Luongo?

They believe they a design that competes on a physics basis with the the mighty icon of modern aviation, the gas turbine, though they're far off yet economically. My take is their essential contribution is to up the power density of the electric motor via a super conductor application from the usual 1kW/kg to as high as 20kW/kg. That compares to ~8kW/kg for the typical gas turbofan.

A major issue is the electric power source which would be the usual scramble for fuel cells, batteries, or even a combustion powered electric generator.

Electric 'jet' aviation would have several benefits:
-Engine itself would be over 95% efficient versus 60% typically for the turbofan
-Plenty of electric power (from whatever source) to run electric actuators instead of hydraulic
-With at least a partial hybrid battery system, recapturing some of the 16000 megajoules of Mgh energy of a large jumbo jet descending from cruising altitude becomes a consideration.
-Eventually the engines could be substantially lower weight than gas turbine comparables.
-Faster power up response.

Overview:
http://www.drives.co.uk/fullstory.asp?id=2033

In Applied Superconductivity, IEEE Transactions:
Next Generation More-Electric Aircraft: A Potential Application for HTS Superconductors,

Superconducting Ducted Fan Design for Reduced Emissions Aeropropulsion
Cyrus
#15
Jul31-09, 06:02 PM
Cyrus's Avatar
P: 4,777
Quote Quote by mheslep View Post
Anybody familiar with the just released FSU electric turbo fan research by Masson and Luongo?

They believe they a design that competes on a physics basis with the the mighty icon of modern aviation, the gas turbine, though they're far off yet economically. My take is their essential contribution is to up the power density of the electric motor via a super conductor application from the usual 1kW/kg to as high as 20kW/kg. That compares to ~8kW/kg for the typical gas turbofan.

A major issue is the electric power source which would be the usual scramble for fuel cells, batteries, or even a combustion powered electric generator.

Electric 'jet' aviation would have several benefits:
-Engine itself would be over 95% efficient versus 60% typically for the turbofan
-Plenty of electric power (from whatever source) to run electric actuators instead of hydraulic
-With at least a partial hybrid battery system, recapturing some of the 16000 megajoules of Mgh energy of a large jumbo jet descending from cruising altitude becomes a consideration.
-Eventually the engines could be substantially lower weight than gas turbine comparables.
-Faster power up response.

Overview:
http://www.drives.co.uk/fullstory.asp?id=2033

In Applied Superconductivity, IEEE Transactions:
Next Generation More-Electric Aircraft: A Potential Application for HTS Superconductors,

Superconducting Ducted Fan Design for Reduced Emissions Aeropropulsion
I wouldn't call it an electric turbine, as it's not using any type of gas cycle. It's just an electric fan unit. This is a nice idea, but it's not getting off the ground until they find a power source: which is a fatal flaw.
mheslep
#16
Aug2-09, 02:59 AM
PF Gold
P: 3,098
Quote Quote by Cyrus View Post
I wouldn't call it an electric turbine, as it's not using any type of gas cycle.It's just an electric fan unit.
You're right
This is a nice idea, but it's not getting off the ground until they find a power source: which is a fatal flaw.
Yes it is problematic, though I doubt fatal. The first IEEE paper points out the possible sources: traditional gas turbine electric generators, batteries, and fuel cells. The gas turbine generator would use traditional fuels, with the advantage (as the paper details) that there are significant aircraft design advantages in decoupling the propulsion source from the main energy conversion. Batteries and fuel cells are unsatisfactory at the moment only for 100% electric designs; a hybrid power source would still present major advantages: e.g. much quieter take-offs and landings, more efficient operation, etc. Even in an all battery or an all fuel cell design, the limitation is essentially only range (though that is drastically shorter for now, maybe 30x shorter.)

I believe, as the authors suggest, that the primary shortcoming of the concept at the moment is the economics of superconducting electric motors and associated cryogenics plant. Otherwise the advantages of electric ducted fans are such that I'd expect them to be already in use in niche aviation roles.
mheslep
#17
Aug2-09, 08:35 PM
PF Gold
P: 3,098
Example all battery case

Regional jet like this Bombardier CRJ900.
http://www.aerospace-technology.com/projects/crj900/
Assumptions:
-Replace the entire max Jet-A fuel load of 11150 liters (9 tons) with batteries
-Battery energy density 0.2kWh/kg (about 55x worse than Jet-A)
-Replace 50% eff. gas turbo fan engines w/ 98% eff HTS electric fans

Gives me a maximum range of 150+ miles.
Cyrus
#18
Aug2-09, 09:05 PM
Cyrus's Avatar
P: 4,777
Quote Quote by mheslep View Post
Example all battery case

Regional jet like this Bombardier CRJ900.
http://www.aerospace-technology.com/projects/crj900/
Assumptions:
-Replace the entire max Jet-A fuel load of 11150 liters (9 tons) with batteries
-Battery energy density 0.2kWh/kg (about 55x worse than Jet-A)
-Replace 50% eff. turbo fan engines w/ 98% eff electric turbo fans

Gives me a maximum range of 150+ miles.
If your numbers are right, that's terrible performance.


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