rjbob

My Feedback: (8)

I was able to attend the Arizona Jet Rally a couple of weeks ago. Although I'm a turbine modeler, I came away VERY impressed with some of the EDF's at the rally.

The 13 pound Jet Hangar International A-7 and the BVM T-33 both flew with authority and at good speeds. NOW WE'RE TALKING!

I'm thinking about pulling a few pounds of turbine related equipment out of a Y/A Starfire and installing an EDF system.

Any suggestions?

perttime

I just think that you are going to need a big stack of LiPo's, to power the big ESC, big motor and big fan.

It will not be cheap but I do not know how the cost stacks up with turbine power.

For small jets, EDF is really a no-brainer.

mmmmm, an airframe made for turbines, might be stronger/heavier than you need for EDF.

Larry Dudeck

My Feedback: (1)

Bob Violet (BVM fame) seems to agree with you. He has (is?) developing an e-power conversion for some of his olger GDF models. Initial performance reports are very positive but I have heard grumbles about the price. But with BVM products, I have been told you get value for your investment.

I don't think EDF will replace turbines. With EDF power systems, the maximum thrust is developed on the ground. As the plane accelerates, the thrust is reduced until the thrust developed exactly equals the aerodynamic drag. Thus, the maximum velocity is self limiting.

Compare that to the trust produced by a turbine. In this case the thrust is essentially constant so in the same airframe, top end velocity will be greater than the EDF version. If maximum velocity is what one is aiming for, the turbine is the power system of choice. From my point of view, I don't see much difference between an EDF at 130 mph versus the same airframe being pushed at 190 mph with a turbine. But that's just my opinion.

In smaller airframes ( up to 50 inch WS) the EDF system is the way to go. But once you get into larger sizes I think the economics favor the turbine.

tIANci

EDF will be popular based on a couple of things, RELIABLITY and COST. Its about the reliability of equipment (ESC, motor and especially batteries) and the cost of the same.

DepronJet

i am just getting into EDF,
the first design is a complete success
i know there are lots of Delta's and lots of EDF's out there!
if only the wind would drop so i could complete flight tests on the latest mods[&o]
it was blowing so hard this morning i couldnt even trim it (i Miss my Analoge Trims),

perttime i am working on the smaller EDF's an with the right motor in the right airframe they can sing

there is a market for the RCers that what to grab the TX a few Lipos and head out to the local field with a small but nippy EDF

Ray

Ray Davis

My Feedback: (1)

I own three turbines, I'm an AMT USA rep. But the Alfa MiG, alone, has opened up my eyes to the future...tho it may not be one I particularly like.

There has been a dramatic shift already re electrics vs. glo prop models and jets; parity nears, or exceeds, for the smaller stuff already. And that's today...we are really only in the infancy of electric power, whereby turbine and glo/gas are mature and lesser expected real improvements on the horizon. Imagine the next quantum jump in energy density....Li technology is hardly the end of the line with the whole world a greedy market for ever greater efficiencies and economies re electric power storage and propulsion! Easily to visualize in five years that we'll have double the energy density for much less cost than today's stuff...plus motors of ever greater power/weight, etc. EDF will be dominant in all aspects....performance, economy and convenience. Even the sound ain't too bad!

That's just one thing...another is the historical and continued loss of flying sights unfriendly to noise and fuels, plus the ever decreasing available land for any larger model. With that projected loss...turbine flying will further have to migrate to airports and become ever more exclusive and event-dependent. Fact of life....electrics also are just more friendly, more convenient, will be ever more reliable and cheaper.....if not already! Try flying yer small turbine model at the local soccer field vs a same size/power EDF. No contest as to which has a better chance of coming back a second time!

Personally, I think turbine power is at it's heyday right now, and maybe for the next five, even ten years, at best. I love 'em(!), VERY thankful I've had my opportunity, 'cause there is nothing like it, the sound/smell/the whole experience! But, within another generation we will be the dinosaurs, out numbered in the sky at jet meets...growth will become static and diminish.

I fly my MiG to practice for the 'real' (turbine) experience, but love the quickness from car to into-the-air at convenient sites...stuff that will be all the more a premium in the future. Thankfully, I'll never have to go beyond the occasional little EDF, as I've likely five/ten years at best left flying RC. So, I'll enjoy the 'real' thing while I can, but damn...those EDFs are sneaking up on us too fast for comfort! Besides, when they get to the point of truly kicking our asses in all aspects of performance and price...then what's the point of flying a 'lame' technology, say, beyond nostalgia?

Ray

outlaw29

I am certainly not an expert on electric but, the $3000.00 needed to buy a turbine will buy a big brushless motor, high amp ESC and a very tall stack of Lipo's. EDF just wound sound as cool as a turbine but, it sure will spool up quicker. With battery technology advancing as quickly as it is, i thing EDF jets are here to stay!!

DepronJet

Ray

i read your posting and you are a true RC enthusiast

if it has wings FLY it
i enjoy electric flight for the simplicity of it but ohh boy when i attend the airshows and help the turbine guys,
i have to admit i love the smell of the turbines..
and they love the way i connect battery and throw it into the air

the future of EDF and power sorce/packs will evolve,
the I.C engine has not changed in 15 years but electric flight is continually evloving,

the only limit is your imagination !

Ray U.K.

tIANci

Once the cost of batts drop a little lower and also become more reliable then it will really be a hit. At present even good branded batts will swell ... its like pouring jugs of fuel down the drain. Like what Ray says ... the ease of getting it out of the car to the air is really fun! For me a 40 sized EDF will be sufficient, well maybe a 60/90 one!

Kip Jackson

My Feedback: (1)

Here are some videos of my F-16 and my Lynx. The F-16 is on 5S and the Lynx on 4S.
Enjoy.
KJ
http://www.rcgroups.com/forums/showp...&postcount=291
http://www.rcgroups.com/forums/showp...&postcount=293

tIANci

I just dowloaded a video of the BVM Electra ... DROOL DROOL ... it is so tempting.

a65l

My Feedback: (17)

I saw a BVM electra fly at Fentress this weekend. Very impressive. Also there were a converted BVM F-86 and a Starfire with a Scheubler setup. The BVM electra was flying with the full BVM setup. Lots of bucks there, could get into a used or cheaper turbine for just about the same amount of money. Add in a second set of batteries and cost favors the turbine. Not to mention the hour plus that it takes to recharge the batteries.
A strange stat is that there were just about as many nitro DF's there as electrics. The electrics seemed to have a noticable performance edge over the nitro fans, especially at slower airspeeds.
One point that hasn't been made is that you can fly an EDF, any size, without a waiver.

Seems like every day I check, there's a new EDF kit or arf. I'm stoked, and I see quite a few more in my future.

Andy

tIANci

Andy - EDF up to 70mm fans are still very affordable, look at the new Twister and your own Sport Jet. I still love the smaller 50mm fan ones too and like you said, there are new models coming out all the time. I would love the Electra, costly but then its easer to run compared with a turbine of the same size. Again, with EP, its paying a premium for convenience. How's your SJ now? Mine is still half built ...

a65l

My Feedback: (17)

I agree about 70mm jets, plus they're big enough to scale up and will take a bit more weight, but are just a bit to small to fly off grass with gear. The 90mm jets seem like they would do better getting off grass due to larger gear. Yes, they're always bungee launch but I like the gear thing.

SJ is doing great, made it debut at the Mid Atlantic Jet rally this weekend. Wound up knocking the nose cone off on landing but was easily fixed with CA.

Andy

tIANci

My SJ will not have any UC so it will be hand launch and a gingerly landing.

BalsaBob

My Feedback: (24)

I think Ray's response is right on ........ very well said/written. Additionally, it is now common to see an article on 'High Power EDF' in many RC publications (including the new issue of RC Jet International). Though it has already started, I think we will all soon see a further dramatic increase in the number of available EDF kits and ARF's. There are also many people in this hobby that like jets and would prefer to fly a small-medium (25-60 size) jet ..... even though they could afford the full large turbine setup. The EDF's will certainly fill this void.

PS: Like Ray, I also have an Alpha Mig. Bang (and fun) for the $$$$, I think this airplane is worth every penny. Bob

Ray, I am planning to go to the Big Apple Jet Rally ..... are you going ?

ClemenTang

The perfect batteries...

http://www.aircraft-world.com/shopexd.asp?id=5041

This might be the knock out blow.

Clement

Ray Davis

My Feedback: (1)

Hey BB, thanks for the kind words re what I wrote above!

I'm now additionally flying a Wren 44 Gold turbine ($2200, weighs a little over a pound, ten-pounds thrust, size of a large soda can...) that has ever increasing airframes to choose from. And it is about the ultimate in model turbine refinement....weight/size, best specific fuel consumtion, etc. etc. And that size/thrust EDF is already damn competitive re performance and all aspects of cost. Already!

Small(er) is kinda where I'm headed.....and I think the 'Bigger is Better'...is BS. Smaller just as easy to see, as they fly in closer, no worse in any wind, available to smaller fields, but especcially much less inertia/more manueverable/outa trouble much more easily/more margin for error. Older I get, smaller I like. And again.....that size range...that's where EDFs already shine and even w/ several battery packs are more than cost competitive.

My Alfa MiG now is Screamer powered w/ a 4s LiPo pack....tremendous performance(!)....a favorite, low stress and convenient...JET.

Won't be at the BA jet rally, too many others up in NE...I used to go all over but have cut back a bit. Co-CDing our own New England Jet Rally, Gardner MA Airport, Aug 18/19. Maybe see you there.....

Ray

evan-RCU

Not the knock out blow... sounds interesting 2300mA, 26/52C Only drawback is the hard case and lower voltage (3.3V per cell)

P. Richards

My Feedback: (3)

EDF's are the future of ducted fan jets and as soon as the UAV batteries are released to the general public, we are talking huge flight times lighter packs and fast recharges.
Thunder Power has recently released a new generation 2200 extreme pack the technology changes approximately every three months...

P. Richards aka Swat Team

Tomcat_104

My Feedback: (42)

I went through the same arguement and ended up going with EDF. I'm building an Avonds F-14 so I needed two of everything. When I compared the cost of two turines to two EDFs the choice was clear to me. Like the above posts said EDF is still growing and hopefully will become a little cheaper. Until then I'll just fly once and then recharge. The cost savings was about $4000 to me. Not chump change in my book.

ClemenTang

http://www.jethangar.com/

some had actually went below $2000.

Clement

Ray Davis

My Feedback: (1)

Aw...turbines ain't all that bad, Tomcat!

You mean the Avonds F-15......I built that as my first turbine model......single engine, split intake and exhaust to retain the scale look. Most twins are similarly powered...cheaper/lighter, less complication as singles. The Avonds 15 flies beautifully on, say a JetCat 120....I dunno, maybe $2500.

The Wren 44-Gold (I have one), weighs 18-ounces alone, marginally larger than a soda can (26-oz flying weight w/ battery, ECU, etc..), electric, flawless start, almost 11-pounds thrust. Ten minute flights w/ 40-ounces fuel. Under $2200 (JHH). Now an exposion of scale and sport models out for it specifically. Pretty tough to compare EDF, in that size anyway, as any kind of real advantage unless maybe your site has a 'noise' problem!

Ray

tIANci

Talking about EDFs and all ... you guys seen the new BVM F86? Its coming soon, built for the Vio Fan!

Tomcat_104

My Feedback: (42)

Ray,

I'd like to have an Avonds F-15 if you know where one is. I looked at JHH several times and talked to Larry Wolfe there. My Avonds F-14 calls (and has been flown on) for 2 Wren-54's because of the weight of all the swing wing aluminum parts. For good performace it needs around 27 lbs. of thrust. I'm not against turbines, would actually like to own some. It's just that they cost a lot and you have to have an AMA Waiver to fly them. I'm disabeled now and the closet instructor is over 3 hours (one way) away. For now the EDF is looking better and besides clean-up is a breeze then. If I ever find a F-15 maybe I'll try the one engine thing. Have you ever seen the video of the "one winged" Israel F-15? I've got it and can send it to you if you haven't. It'll make anyone an instant fan of the F-15.

David