Jgwright

Have a look at this for the latest EDF 144mm dia unit called the KF-ProFan 144-17 and the brand new sports jet KF-ProJet.

http://www.rc-network.de/forum/showt...eistungsklasse

Check out the electrical cables, getting like the ones for the house supply! They are now running at 280 amps on 12s pack which gives them an unbelievable over 10 Kw. They plan on 20 Kg thrust and reach 17 Kw.

Have a look at the video
http://www.youtube.com/watch?feature...&v=NmZYv83t-y8

Anyone who thought EDF was wimpy think again!

John

marc s

John,

Appreciate the post, very impressive indeed.

Its good to see some publicity too for MGM Compro on the ESC's. I have used MGM for ESC's for many years and they are simply the best, amazing range (as you can see some huge monsters) and great to deal with.

Our EDF Stinger v2 runs an MGM ESC faultless ......

marcs

Ron101

My Feedback: (22)

This is the stuff that really excites me, there is no limit to the amount of power an electric motor will put out. Except for the failure point on the parts used...
internal combustion can't say the same... there is a point where you have reached the max power

The day will come that people will want electric cars not because they are green but for the performance .... nothing will accelerate like an electric motor

I know that most guys in this turbine thread could care less (or at least act that way) but this stuff truly excites me.... to think how far we have come in such a sort time to where we will be in the future is amazing.

These guys are pushing the edge for the rest of , there plane performs amazing

ravill

My Feedback: (11)

Doesn't this belong in the electric jet/foamie section?

Vincent

My Feedback: (61)

3min flights ... yawn. Its fine running in a pod setup but once its installed in something scale the intake would have to be very over sized to suck in all that air just like the old DF days.
Vin...

rhklenke

My Feedback: (24)

That's the real limitation of EDF's. Their exhaust velocity is so much lower than a turbine that they have to move a large amount of air for equivalent thrust. Since full-scale jets use turbines, most scale jets have too small of an intake(s) to perform well - at least as well as a turbine.

I was talking to a guy who was thinking about doing a PCM Models L1011 as an EDF. It would *have* to be done as a twin because you simply could not move enough air through the center engine intake - regardless of which fan unit you tried - to make it perform anything like it does on a single turbine.

EDFs are cool, but I don't expect them to replace turbines - at least not for scale projects. Even if the price comes down and the batteries get better.

Bob

Eddie P

My Feedback: (4)

This falls into the category of "if it's cool, have at it". But like your buddy with a wife you may not have jumped to date when she was single, why rain on anyone else's parade?

One thing nice about scale EDF. Single, twin, four motors, eight motors - it's just as easy. No need to try to stuff a big single motor and fan into a scale nacelle like we try to do with a turbine. I've had many 4 engine EDF models because it was more scale, just as reliable (well, more reliable) and sounded really great. All with EDF. I don't see any of this as a limitation with EDF so much as a difference that needs to be catered for in the design and setup. As far as engine inlets go, the EDF size minus the motor cross section is the fan swept area. Fan swept area is smaller than the EDF size. Also, with modern fan units at high power you can reduce the inlet size below the fan swept area, to as low as 80 percent, even 75 percent if the ducting is simple and the fan is appropriate. So the intake sizes today can be much smaller and completely scale for EDF as long as the design is properly engineered for EDF. Talk of huge bunny ear inlets is ICDF and old EDF technology limitations... That's like saying turbines take 12 seconds to accelerate. While it was true at one point, today modern turbines do much better by smart engineering and advances Same for EDF with high power, high RPM fans. Electric Ducted Fan jets today are not our father's exploding, shaking and seizing .91 slime machine of yesteryear so comparisons are really not even in the ball park. Also, efflux velocity today on high power EDF is "plenty fast enough for the old man" (old star wars quote). If you can repeatedly, legally go faster than 200mph with an EDF as is common now, on a dry day in Texas during a burn ban, where is the contest anyway?

PS, all my EDF's are set up for 7 minute flights or longer. My turbines are set up for 7 minute flights too. Many guys fly shorter for whatever reason, but it's a choice that can be changed with a setup goal in mind, that is planned according to taste.

All that being said I truly enjoy flying turbine and everything about turbine RC jets. And, I equally love EDF and am happily enjoying the advances that have come with it. As much as there will never be a direct replacement (IMHO) for the roar and unique "jet" performance capability of a nicely built turbine jet model - sometimes the bang for the buck, excitement and ease of a quick couple of flights with a fast performance EDF CAN NOT be beat!

ModellbauUK

I agree John that EDF is amazIng. I timed the flight to be 5 mins plus so not far off a ballistic jet turbine flight. 

jetster81

It should be noted that this is heart stopping amounts of electricity being applied here and is only for the experienced. I have a Ramtec?Scorpion combo on a Falcon 120 and performance is more than adequate and I get 7 minutes plus flights. Would like to get a closer look at this setup. has anyone noticed the price? probably in turbine territory is my guess.

SJN

That power system looks like something that will shock you too death if you touch the wrong bits

Eddie P

My Feedback: (4)

Yeah, it's almost approaching something half as hazardous as our toasters and iPhone/computer charger outlets at home that we use 50 times a day! At the end of the day driving to and from the flight field is probably the most dangerous thing we do in our lives. So as long as we are as, or more careful than that activity, we should all die of natural causes such as a grueling drawn out sickness... or maybe car crashes after dismemberment and failed resuscitation. Or quick and spectacular, RCU headline grabbing death by EDF, if we are lucky. So we got that to look forward to. Which is nice. Ha ha. But in all seriousness, yes. Who approaches a turbine jet with out a clue and some level of respect and learned experience? This indeed is serious big boy toy action, though it is not uncharted territory to experienced modelers. It took a lot of careful, well intentioned operational experience overt the years by the jet community to convince most AMA modelers and leaders that RC jets were not the devil itself wearing a fiberglass shell.

Ron101

My Feedback: (22)

It's a 12s setup it's under 60 volts it won't do a thing to you

14s and up you should worry....12s and under is safe to plug in with dry hands it can't break the skin

LittleBob

Are you sure it wont do anything to you. Try sticking your toungue out and touching the positive and neg of the 12 cell pack on it and see if it will do anything

jetster81

I was not talking about plugging in I was talking about shorting out .

Ron101

My Feedback: (22)

I'll tell you what you lick up your Kerosene and I'll lick my Lipo

it's really a bad iead

k_sonn

My Feedback: (32)

John, thanks for sharing. JR and Schubeler have always been on the cutting edge of EDF techonolgy.

EDF technology has advanced at such a rapid rate that it may be hard for those who aren't in it to keep up with what's going on. In fact, it has advanved so much that now all of my large jets are converted to EDF. I have one turbine left to sell. Anybody interested in a JetCat Titan SE? I'll make you a good deal.

Kirk

Vincent

My Feedback: (61)

It looked like there were (2) take offs (flights) in the 5:40 video??
Vin...

Ron101

My Feedback: (22)

Thanks Vin and Ralf for making us EDF pilots feel so welcome... it really makes me want to load up my car and drive a day to an event, spend thousands of dollars to come hang out with guys that really love what I do [:@] I'll pass

no wonder it's hard to shake that elitist reputation [:'(]

SteveC68

Oversized in what way. An EDF will fly just fine on a 70% FSA intake. In fact the only thing an oversized intake is going to do is slow down the top speed.

ron Sweeney

Ron, re i.c. engine limits, Have you ever ben to a drag meeting? Ron.

ravill

My Feedback: (11)

Touchy, touchy!!!

Ron101

My Feedback: (22)

Hey, that really helps me think your not an A hole

rctech2k7

My Feedback: (1)

Just wanna share about this technology, I believe most EDF guys knows this principles already.

We knew that in EDF the head of stream is constant and also there's no added heat or thermodynamics. In order for the EDF to increase exhaust velocity like in turbine, we can change ducting diameter.

For reference here how it works. In EDF steady stream, there's no change in air density and volume flow rate is constant from inlet (intake) to outlet (exhaust).

The volume flow rate, Q

= Volume / time
= Area * distance / time
= Area * velocity
= (pi) * (radius)^2 * velocity
= (pi) * (Diameter/2)^2 * velocity
= (pi) * (1/4) * D^2 * v
= (3.14) * (0.25) * D^2 * v
= 0.785 * D^2 * v

Since Q is constant
Qin = Qout
we can eliminate constant value
Din^2 * vin = Dout^2 * vout

Now therefore,

EDF velocity / exhaust velocity = (exhaust diameter / EDF diameter)^2


Exhaust velocity can be expressed by:

Exhaust velocity = (EDF dia. / Exhaust dia.)^2 * EDF velocity

shaneyang

Good to ready this post

mikes68charger

My Feedback: (34)

Really all it is going to take is a step up in battery tec

At 250 amps at 12s thats going to take some serious mah not to kill your liops

Even now byron fans as edf are in the 90 to 120amp range so they use 5000 to 8000mah packs for 4 to 7 min

So doubled the amps double the mah then you will double the weight