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Old Feb 25, 2004, 12:12 AM
Unsafe at any speed
Wiseguy's Avatar
Rochester, NY
Joined Jun 2003
442 Posts
Best power/weight EDF?

I'm looking for the best fan/motor/battery combo in terms of power to weight...to price (I'm cheap!)...for use in the VTOL project being discussed at this thread:

http://www.rcgroups.com/forums/showt...hreadid=203084

...any suggestions? The pro's are working on big 1:9 scale F-35's, but I'm just trying to build something that will work...or at least help develop that idea.
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Old Feb 25, 2004, 07:07 AM
Registered User
Pasadena, California, USA
Joined Mar 2002
472 Posts
The Vasa fans are pretty light, made with carbon fiber. Wattage Powerfan 400 is a little more heavy but a lot cheaper. The Wemotec is the heaviest and most expensive, but very high quality. My test shows at under 300W input the Wattage fan has almost as much thrust as the Wemotec.

http://www.rcgroups.com/forums/showt...rust+important

-and-

http://www.rcgroups.com/forums/showt...89#post1807489
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Old Feb 25, 2004, 07:21 AM
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Chattanooga, Tennessee, United States
Joined May 2003
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"Best" and "cheap" are going to be mutually exclusive, so you need to decide which you want!

Depending on the size of your VTOL one of the best combos would be a Mini AC 12-turn, in a carbon fiber Vasa (VAS055) ducted fan, without nacelle. Run that off a high output 3s Lipoly and you could be good to go: - of course that combo, complete with ESC, will set you back almost $300. There are Astroflight 010 and 020 powered ducted fans too, but they are close to $200 (without battery ($75) and ESC ($50)).

Otherwise get an EDF 50 for $15.75, a $20 ESC and a $15 NiMh pack and you've done it all for only $50.

Cheers, Phil
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Old Feb 25, 2004, 01:12 PM
Unsafe at any speed
Wiseguy's Avatar
Rochester, NY
Joined Jun 2003
442 Posts
Will an EDF 50 produce enough power to lift itself and the battery pack straight up? That's the kind of performance I need, and the fact that I can't recall any images in my mind of jets hovering (3D-style) isn't helping =P

Brushless motors are probably going to be a necessity, I'm okay with that. It's not like I have the money to build this myself right now anyway, heh

I'm thinking about going the ultra-light route with this project, so the smaller the better...and if it can give me a 2:1 thrust to weight I think I might be able to work with that
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Old Feb 25, 2004, 02:16 PM
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Atlanta Hartsfield, Georgia, United States
Joined Apr 2002
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The EDF-50 barely picks itself up, let alone a battery pack. It will produce 2 to 2.5 oz. max thrust -- depends on cell count and whether you added an intake duct.
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Old Feb 25, 2004, 03:29 PM
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Chattanooga, Tennessee, United States
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Sorry about my sense of humor, Wiseguy - I agree with Mr Cochran over the wimpiness of the EDF 50 - I wasn't making a serious suggestion that they would be any good for your purposes!

Isn't there a ducted fan/jet section somewhere in this forum - they'd be the guys to ask.

Cheers, Phil
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Old Feb 25, 2004, 10:49 PM
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Wiseguy's Avatar
Rochester, NY
Joined Jun 2003
442 Posts
I figured power systems might work Yeah, I've already got some threads cookin' in there...thanks for the info.
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Old Feb 26, 2004, 05:30 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
I believe the problem you'll run into is that EDF systems are designed to develop very high eflux velocity, NOT static thrust - which is what you need to lift a model. The blade profile for good static performance would be virtually useless in level flight.

It has been done, however, by a member here from the UK. It was a long project, and very, very expensive (three brushless systems with gyros and other control circuitry, if I remember correctly)..
..a
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Old Feb 26, 2004, 08:13 AM
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JDCochran's Avatar
Atlanta Hartsfield, Georgia, United States
Joined Apr 2002
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He did a harrier-type craft, didn't he?
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Old Feb 26, 2004, 09:58 AM
Look what I did:D
plumb's Avatar
orlando,Fl
Joined Mar 2003
928 Posts
the vasa fans use a glue that doesnt hold up verry well in a slight crash or even just dropping the motorless unit makes the joints break loose. plus they are too expensive

Brad
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Old Feb 26, 2004, 12:13 PM
Unsafe at any speed
Wiseguy's Avatar
Rochester, NY
Joined Jun 2003
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If you're speaking about Doc Watson, his project is still under construction...complete with crazy brushless motors and gyros...but it isn't quite there yet. I think if I'm going to make any progress in this problem I'm going to have to attempt a completely different approach--namely going for a really lightweight and [relatively] low power solution. I wonder if it would be possible to have two sets of blades and have something to switch the motor power from one to another?
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Old Feb 26, 2004, 12:57 PM
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JDCochran's Avatar
Atlanta Hartsfield, Georgia, United States
Joined Apr 2002
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Yup, Doc Watson. Why doesn't he use LiPos?

http://www.awatson1.fsnet.co.uk/
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Old Feb 26, 2004, 01:52 PM
Watts your motivation
roccobro's Avatar
San Bernardino, CA
Joined Aug 2003
6,512 Posts
Wiseguy, I'm planning all my future projects on CD motors in the EDf-50 to 64 range. I've seen EDf-50's push 200 gm of thrust with the unit weighing in same as stock. The same gent made a neat EDf-55 unit that weighed about 45 grams (whole unit) and it also made 200 grams thrust. The 55's and 64'swill take Himaxx motors no problem som you wouldn't have to custom wind anything.

Personally, I been following your posts as it really involves my loves. Light weight and EDF's. Just as in auto racing lighter is better. Less mass to push around, and in our aircraft hobby, less mass to shove into the ground Less inertia= less damage.

GWS's are on the cheap, so as the Himaxx's that is why I use them. Irate Lipo cells are excellent product, and are the best bang for the buck right now if you build your cells. This is why I said VTOl can be done for under $1000 if you aren't all anal about highest efficiency components and focus on the biggest problem, lift vs weight. All else can be done with gyros to some degree or another (not expensive either).

Justin
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Old Feb 26, 2004, 02:26 PM
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Fred Bronk's Avatar
In Heli Wonderland
Joined Aug 1999
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If the Doc went ot Lipos he would be off the ground now.

But otherwise it is like Kiwi and Andy said. Cheap will not get you the power you want and fans are made for Eflux, not thrust.

Bottom line is you probably won't be using any type of brushed motor at all for what you want.

Maybe look at the midi or mini wemotec fans for a start with the new Himaxx motors. The smaller fans are composite, and then you get to CF, and the price goes up too!
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Old Feb 26, 2004, 04:57 PM
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Wiseguy's Avatar
Rochester, NY
Joined Jun 2003
442 Posts
Do you really think that battery weight is the only thing keeping Doc Watson's project from hovering? Because it looked like you could save a lot of weight just on that airframe, judging by the pictures...replace all that 1/8" balsa with a carbon fiber skeleton in solite, with some foam here and there perhaps? (I never said it'd be pretty!)
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