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Jul 20, 2011, 03:16 PM
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Discussion

New to EDF's Trying to make an EDF Trainer


Hi all,

I have reached the point where I think I am ready for some EDF action. I have gotten bored with my warbirds performance, and the Titan airhogs I converted are fun (have two right now one with lights for night flying and set up for around 50mph top speed, and one for fast flying with a high kv motor would guess its about 70mph WOT).

I love flying them and building them but I just don't feel challenged with them anymore.

Hence, I want to try to convert a titan into an edf. I don't think this necessarily belings soley in the titan bash thread because I am asking for basics of edf usage. I picked up a 64mm edf from hobbyking (ADH300 unit with 4300KV running on 3 or 4s lipo). I am wondering what you scracth builders are using for home made ducting, and if you have any building tips. Such as ratio of inlet to exhaust sizes, lenghth of exhast duct, basically anything you think someone new to this needs to know, i.e the stuff you wish you knew when you got into it.

thanks for any advice
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Jul 20, 2011, 10:47 PM
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Empty Beer or Soda cans are 64mm ducting sources.
Check the windings on the ADH300 for loose wires.
I had one come adrift and snag a passing magnet.
IMO a flat foamie pusher Or prop in slot model is a Good 'trainer'
Very quick build (great for crash replacements) MORE perf than a similar motor/battery EDF will give.. So you will get all the excitement in an easily/cheaply replaced /disposable package... until crashing is no longer an issue.
Jul 21, 2011, 07:13 AM
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scote621's Avatar
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Quote:
Originally Posted by Bare
Empty Beer or Soda cans are 64mm ducting sources.
Check the windings on the ADH300 for loose wires.
I had one come adrift and snag a passing magnet.
IMO a flat foamie pusher Or prop in slot model is a Good 'trainer'
Very quick build (great for crash replacements) MORE perf than a similar motor/battery EDF will give.. So you will get all the excitement in an easily/cheaply replaced /disposable package... until crashing is no longer an issue.
So the 64mm edf fits right into a soda can? Never would have thought of that...or does it require some trimming? I think I will try to make the titan, if it crashes then il try something like a profile foamie. It's been a long time since i have crashed anything.
Jul 22, 2011, 09:19 AM
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SNice's Avatar
I've done a few EDF scratchbuilds with various duct designs. Some have worked well, others have not... For exhaust ducting, I usually use photo printer paper. It's stiff but not too rigid, and cuts and forms well. Another source of exhaust ducting can be foam coffee cups or fast food drink cups - they work great for longer exhausts.

My inlets are usually foam, but in an effort to clean up my inlet ducting, I have started using the photopaper as well. It just has to be secured well so that it does not collapse under pressure from the fan. Cleanliness of the inlet is very important. If possible, try and keep wires, servos, ESC's etc. out of the intake area -- you also want to reduce/eliminate corners, sharp turns, and drastic changes in diameters.

My inlets are always at least 100% FSA, sometimes a little larger. Exhaust areas are 85% FSA for a good mix of thrust and speed.

As far as intake/exhaust length -- I usually put my motors where I need them to get the model to balance properly. I have heard different lengths based on EDF diameter -4-6 or something for exhaust, but we're not using turbines or breaking 200mph so I'm not sure if it matters too much in our parkjet foamy applications.

EDF's are fun and look/sound so cool but they are not nearly as efficient as props. If you do not have a watt meter, I suggest you get one so that you can be sure that you have the right combo of esc and battery to go along with your motor. My flight times are usually 3-5mins (depending on battery)and as soon as my timer goes off, I bring her in! EDF's are amp hogs so I generally only use batteries rated 30C & up.

I've done a few EDF titan conversions, and the one below is by far the best. The ducting is clean and it is a super stable flier. Inlet is photopaper, exhaust is a burger king soft drink cup. Ducting formers were made using 1/2" pink foam. The outter shell was made using depapered dollar tree foamboard (readiboard). It uses a 4300KV 64mm edf. It can use anywhere from 1300 3S 30C lipo and up (the largest I've had in it is 2200 30C 3S). Haven't tries 4S yet but that would reqire an ESC upgrade and I'm not sure if the motor could handle 3S.

I added anhedral to the horizontal stab to get it to look "habuish" like - not necessary but I thought it looked cool!

There are build pics at the end of the video!
Air Hogs Titan Glider - EDF Sport Jet R/C Conversion (7 min 19 sec)
Last edited by SNice; Jul 22, 2011 at 09:45 AM.
Jul 26, 2011, 03:45 PM
http://stevesrcaddiction.wordp
scote621's Avatar
Thread OP
Quote:
Originally Posted by SNice
I've done a few EDF scratchbuilds with various duct designs. Some have worked well, others have not... For exhaust ducting, I usually use photo printer paper. It's stiff but not too rigid, and cuts and forms well. Another source of exhaust ducting can be foam coffee cups or fast food drink cups - they work great for longer exhausts.

My inlets are usually foam, but in an effort to clean up my inlet ducting, I have started using the photopaper as well. It just has to be secured well so that it does not collapse under pressure from the fan. Cleanliness of the inlet is very important. If possible, try and keep wires, servos, ESC's etc. out of the intake area -- you also want to reduce/eliminate corners, sharp turns, and drastic changes in diameters.

My inlets are always at least 100% FSA, sometimes a little larger. Exhaust areas are 85% FSA for a good mix of thrust and speed.

As far as intake/exhaust length -- I usually put my motors where I need them to get the model to balance properly. I have heard different lengths based on EDF diameter -4-6 or something for exhaust, but we're not using turbines or breaking 200mph so I'm not sure if it matters too much in our parkjet foamy applications.

EDF's are fun and look/sound so cool but they are not nearly as efficient as props. If you do not have a watt meter, I suggest you get one so that you can be sure that you have the right combo of esc and battery to go along with your motor. My flight times are usually 3-5mins (depending on battery)and as soon as my timer goes off, I bring her in! EDF's are amp hogs so I generally only use batteries rated 30C & up.

I've done a few EDF titan conversions, and the one below is by far the best. The ducting is clean and it is a super stable flier. Inlet is photopaper, exhaust is a burger king soft drink cup. Ducting formers were made using 1/2" pink foam. The outter shell was made using depapered dollar tree foamboard (readiboard). It uses a 4300KV 64mm edf. It can use anywhere from 1300 3S 30C lipo and up (the largest I've had in it is 2200 30C 3S). Haven't tries 4S yet but that would reqire an ESC upgrade and I'm not sure if the motor could handle 3S.

I added anhedral to the horizontal stab to get it to look "habuish" like - not necessary but I thought it looked cool!

There are build pics at the end of the video!
http://www.youtube.com/watch?v=h5aN49vFdAo
Thanks SNICE! thats some great info. I was looking at your "habu" titan and was thiking you used a BK soda cup and foam board for your ducting. I have some dollar tree foamboard, how does that hold up on the belly landings? You use any tape on the belly to keep from dinging the foam? I actually found a camp sleep mat made of polyolefin at walmart, looks thicker than dollar tree foam and though i might make the belly from that. what kind of adhesive are you using to keep this all together? Looks like you made some foam rings to help mount the ducting/fan assembly and then covered them with an outer layer of foam?? if thats correct what kind of foam did you make thouse mounting rings from?
Jul 29, 2011, 10:06 AM
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SNice's Avatar
No problem!

The whole belly is coated in packing tape (after painting)-- it provides more than enough protection from scrapes and scratches due to belly landing. The inner rings also help to add to the strength. It is more than strong enough in my mind. The foam rings are made from 3/4" pink insulation foam. You could also just laminate 3 pieces 5-6mm foam board. The inner duct is rolled photopaper. And the outter duct is rolled pieces of foamboard as you assumed.

It's all held together with the following:

Packing tape, hot melt glue, fabric-Tac craft glue, and foam safe thin CA.
Jul 29, 2011, 02:30 PM
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scote621's Avatar
Thread OP
Quote:
Originally Posted by SNice
No problem!

The whole belly is coated in packing tape (after painting)-- it provides more than enough protection from scrapes and scratches due to belly landing. The inner rings also help to add to the strength. It is more than strong enough in my mind. The foam rings are made from 3/4" pink insulation foam. You could also just laminate 3 pieces 5-6mm foam board. The inner duct is rolled photopaper. And the outter duct is rolled pieces of foamboard as you assumed.

It's all held together with the following:

Packing tape, hot melt glue, fabric-Tac craft glue, and foam safe thin CA.
Ok cool. Im trying to think of the best way to mount it, following your lead. I already snapped the tail once where it was thin right in front of tail (bumped on wall while moving it) glued it back together and added fiberglass tape to the bottom. It seems really fragile right now before mounting anything. I am thinking of adding some foam back in then mounting the cup mount to that and wrapping and taping, and glueing the hell out of it...
Jul 29, 2011, 08:47 PM
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SNice's Avatar
Yes, it remains very fragile until the outter shell is installed!! The inner ducting provides a little bit of support, but the outter shell makes her solid again.
Jul 30, 2011, 09:07 AM
Registered User
LuvEvolution7's Avatar
don't forget that with today's higher power systems, you can get away with a lot less than 100% FSA inlets. Corsair Nut had an F-86 with 70% FSA inlets and it flew awesome. as long as the exhaust is the same size or smaller than the inlet, you should be ok. the straighter then inlet, the better off you'll be with smaller than full FSA inlets. I personally ise 85-90% inlets and 85% exhaust. this is the best compromise when you are looking for speed. for a trainer, use anything that looks right. a perfect trainer is an RC converted Air Hogs glider. they work great and can be podded with an EDF on top of the wing.

Rich
Jul 30, 2011, 09:47 AM
Registered User
D_FAST's Avatar
My first scratchbuilt edf trainer. Back in '08

The plans and build. https://www.rcgroups.com/forums/showthread.php?t=426281


jet trainer (2 min 7 sec)
Sep 15, 2011, 09:30 PM
Registered User
myplanes's Avatar
I am looking for the plans to the "race duck" edf
about 5 years ago I d/l'd one form rcgroups
It had a false front wing and two tail (winglets)
everon controled funny looking plane but really fun to fly super stable.
Oct 15, 2011, 05:59 PM
Registered User

EDF Trainer


I have come up with the perfect EDF trainer, well, actually it a turbine trainer converted to EDF. THe Boomerang range of jets have proofen to be the #1 trainer intro intoturbine jets and I figured that it could also be the trainer into EDF as well.

I have converted the Boomerang Nano from Boomerang Jets by using the Sapac 100mm Dynamax fan, it uses the Scorpion 4035 motor, Castle 120HV esc and a pair of 5300 6s battiers. Its getting 6 minute flights, more than enough power and speed for trainer use.

Someone could also use the 90mm WiMoTec fan with Neu 1415 1.5y motors as a less expensive fan/motor combo.

I am using TAMJETS special intake ducting that he makes up for the Boomerang Nano. This is a special order from TAMJETS but gets all of the air needed for propert performance. Attached are somephotos of the installation, but if anyone is interested, please feel free to contact me.

This is a less trial and eror and a proofen trainer combo.
Oct 15, 2011, 06:03 PM
Registered User

Photos of my EDF trainer


I have come up with the perfect EDF trainer, well, actually it a turbine trainer converted to EDF. THe Boomerang range of jets have proofen to be the #1 trainer intro intoturbine jets and I figured that it could also be the trainer into EDF as well.

I have converted the Boomerang Nano from Boomerang Jets by using the Sapac 100mm Dynamax fan, it uses the Scorpion 4035 motor, Castle 120HV esc and a pair of 5300 6s battiers. Its getting 6 minute flights, more than enough power and speed for trainer use.

Someone could also use the 90mm WiMoTec fan with Neu 1415 1.5y motors as a less expensive fan/motor combo.

I am using TAMJETS special intake ducting that he makes up for the Boomerang Nano. This is a special order from TAMJETS but gets all of the air needed for propert performance. Attached are somephotos of the installation, but if anyone is interested, please feel free to contact me.

This is a less trial and eror and a proofen trainer combo.


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