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View Full Version : Twin EDF set up


fortunanb
08-09-2005, 10:53 AM
Right you experts! At long last I have found this site which gives me hope for the future. FIRST I must make one thing clear. I am an experienced RC pilot to B standard but with IC. My knowledge of Electric Flight is scant and I get TOTALLY bamboozled with the jargon (why do so many motor manufacturers use so many ways of describing their motors?). Every time I try to find an equivalent electric set up to replace a IC motor I get completely lost in the jargon.
So on to my problem:
I have been building a Sukhoi 27 twin jet model from AK models (America) which is designed for a OS91 with prop up front. Now this is not the not I want it to look (or sound) so I want to make it EDF. The airframe mods will be easy enough but outlet area is limited to 3-31/2 inches. So guys tell me what to use? Designed flying weight is 8lbs and I'm prepared to hand launch if necessary. I have ONE Scorpio Fantex 600 fan which I would like to start with but Hey Its probably wrong!!!

Reformed Nitroaddict
08-09-2005, 01:31 PM
ducted fans are not the most effecient powerplant available. For a model of that weight, you would need a DF setup that produced at least 800-1000watts of power, or equivelent to an IC engine that produces about 1.2 - 1.5hp. Hard to imagine a single DF unit that could produce that much power, would probably have to go with doubles.

Ever thought of just a pusher prop?

Also - a model of that size and weight would need to be launched from a bungee launcher, I don't think you could get enough speed with hand launching.


This motor would have enough power to push the plane, but not sure on how you would get it to work with a DF unit: http://www.hobby-lobby.com/brushless-axi4130.htm

jrb
08-09-2005, 03:08 PM
Some of the most experienced EDF guys can be found here ( http://www.rcgroups.com/forums/forumdisplay.php?f=12 ); a few have stopped by here, but many not.

I’m certain it vary possible with a twin Midi setup using Mega 22/20/Xs


BOL,


Jim

fortunanb
08-09-2005, 05:48 PM
Thanks jrb I went to that site and found loads of stuff including a link to "motorcalc" which I'm going to get

jrb
08-10-2005, 12:29 AM
This thread that maybe of interest: http://www.rcgroups.com/forums/showthread.php?t=325806

Paul THE Jet Man !
11-09-2005, 11:46 AM
there is nothing wrong with EDF

infact they can produce 7 lb more then the .91 IC glow DF can.

shubi 120mm fan on a lehner 2250 with 4000 watts from a 12s2p 7400 li-po pack at about 110 amps will give you 17 lb of thrust.

if you want to get that indepth with EDF go to RCG

planebloke
09-03-2006, 12:43 PM
Hello everyone. Please help!
Like some others here, I'm new to edf flight, have been a plans builder and flying instructor for ages. WW2 Brian Taylor scale stuff etc, have also built and flown fast jet type ic models from plans.I am designing in Autocad, a fairly simple but near scale WW2 german jet around a Midifan/Mega 22/30/3 70a controller Ventral fuz type..My question is; what ball-park weight? Span ( will have straight wing, tapered trailing edge ) eflux area? how critical is length of duct here etc.Could go on for ever!!! Many thanks.

nimrod322003
09-06-2010, 07:48 PM
well i am new to the radio control world but not to aviation. i have recently came up with a design that uses two edfs. i have set both of them up in parrel, but i have one edf spinning faster than the other. if i disconnect the faster, run it the other works, when i reconnect the other one ( the first slow one) runs faster. so what do i do to make it work better run with only on esc or what, any information is greatly appreciated.????

AEAJR
09-06-2010, 09:39 PM
Right you experts! At long last I have found this site which gives me hope for the future. FIRST I must make one thing clear. I am an experienced RC pilot to B standard but with IC. My knowledge of Electric Flight is scant and I get TOTALLY bamboozled with the jargon (why do so many motor manufacturers use so many ways of describing their motors?). Every time I try to find an equivalent electric set up to replace a IC motor I get completely lost in the jargon.
So on to my problem:
I have been building a Sukhoi 27 twin jet model from AK models (America) which is designed for a OS91 with prop up front. Now this is not the not I want it to look (or sound) so I want to make it EDF. The airframe mods will be easy enough but outlet area is limited to 3-31/2 inches. So guys tell me what to use? Designed flying weight is 8lbs and I'm prepared to hand launch if necessary. I have ONE Scorpio Fantex 600 fan which I would like to start with but Hey Its probably wrong!!!

I don't fly EDF, so i can't help you with that, but I can help you with getting to know electric power systems.

EVERYTHING YOU WANTED TO KNOW ABOUT ELECTRIC FLIGHT
http://www.wattflyer.com/forums/showthread.php?t=31071

The problem many glow pilots run into is to try and size electric power system based on glow standards. It doesn't work any more than trying to describe a football game using basketball terms. Well, they both use a ball, right?

The key things you will want to learn are in the thread above.

While ducted fans are not specifically discussed, it does not matter. A ducted fan is just another kind or propeller. The concepts still apply.

Nitro Blast
09-06-2010, 09:54 PM
well i am new to the radio control world but not to aviation. i have recently came up with a design that uses two edfs. i have set both of them up in parrel, but i have one edf spinning faster than the other. if i disconnect the faster, run it the other works, when i reconnect the other one ( the first slow one) runs faster. so what do i do to make it work better run with only on esc or what, any information is greatly appreciated.????

A system like that needs two identical speed controllers. Each controller has its own leads to the battery. Ideally, two separate batteries also. What has worked for me in twins, is two identical setups, fully independent from each other with the exception of the shared controller RX Plug, which is usually just a Y Harness from the RX.