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        Build Log Micro MIG 15 Mod -> Silent Seagull EDF

#1 Johannez May 03, 2012 04:01 PM

Micro MIG 15 Mod -> Silent Seagull EDF
 
hello boys n girls!

Sometimes I make a seagull.
first one was the Ping Wing;
X-Twin Mod: The PING WING - RC Groups

and then last year this one;
quick 'n dirty SEAGULL build - RC Groups

and now im building it again, but bigger. and better. and without props... :popcorn:

So i took a HK MIG 35 mm EDF
http://www.hobbyking.com/hobbyking/s...F-17311(3).jpg
Mig 15 35mm EDF Micro Jet EPO

stripped of wings, paint and features,

bought a spare 1 meter-span Graupner Terry Wing
Graupner Wing

and I will cut it into the wings of a seagull, and put them together like this..:

http://johannez.nl/oud/content/images/435.jpg
..well, and then make it look like a seagull, ofcourse. :rolleyes:

http://johannez.nl/oud/content/images/437.jpg

http://johannez.nl/oud/content/images/438.jpg

http://johannez.nl/oud/content/images/440.jpg

http://johannez.nl/oud/content/images/441.jpg

http://johannez.nl/oud/content/images/442.jpg

http://johannez.nl/oud/content/images/447.jpg

baby bath does the job for making the right bend..:

http://johannez.nl/oud/content/images/451.jpg

a bag of boiling water fixates the shape...

http://johannez.nl/oud/content/images/452.jpg

again on the other side..perfect!

http://johannez.nl/oud/content/images/450.jpg

http://johannez.nl/oud/content/images/453.jpg

So after 0 (zero) flights i cut up the MIG, and plan to rebuild it like this:

http://johannez.nl/oud/content/images/445.jpg

-Fuselage will be upside-down, for a lower centre of gravity

-EDF's make a terrible noise, seagulls don't, so I want to dampen the sound of the fan.

-exhaust will be rotating for rudder control

-aileron servo's will twist the wing tips

HOW exactly is something I'm figuring out as i go...we'll see! :)

I cut the fuselage in half. In the middle you can see where the EDF was placed in the fuselage. directly attached to it the whole thing worked like an 'amplifier' for the sound of the fan... So I wanted to make a sound dampening suspension for the EDF. luckily with that fat part in the middle cut away there was enough space inside.. :)

http://johannez.nl/oud/content/images/454.jpg
two rings on the right side will be attachment points for the suspension.

http://johannez.nl/oud/content/images/455.jpg
made a prolonged duct from PET bottles.

http://johannez.nl/oud/content/images/456.jpg
..lots of space!

..I suspended the EDF inside a legging, which i attached to the rings.
The inside of the fuselage I covered with isolating cloth.
http://johannez.nl/oud/content/images/457.jpg

..freely suspened inside the fuselage..!
http://johannez.nl/oud/content/images/458.jpg

http://johannez.nl/oud/content/images/459.jpg

Test Video:
silent EDF set-up test (1 min 51 sec)


T.B.C... !

#2 hanzie May 03, 2012 04:28 PM

Looool!! That's a genious idea! :D
And ofcourse it's another Dutchie! What's going on with Dutchies and seaguls?
For some reasons the guys at my club also like to build seaguls, but those are usually for slope flying. Now I just HAVE to build a duck someday... :p
Good luck with this one! :)
Hanzie

EDIT:
BTW, does that 'silent ducting' system still produce the same amount of thrust?

#3 Jacques.Eloff May 03, 2012 05:50 PM

Johannez - that is genius and I like your use of everyday items - including a child's drinking cup:eek::)

By the way, I have an AEO 35mm unit (special 6,000KV) that is much quieter than the SkyAngel unit - would be ideal for your gull.

Jacques

#4 Johannez May 04, 2012 01:51 AM

@hanzie:

I don't know, I never measured it.. but the duct is open and at about the diameter of the fan all the way though, (where as the original MIG fuselage had two 'expension chambers' inside) and it pruduces a good steady airflow.. i guess it should be OK. the whole thing is a bit heavier ofcourse, but I bet the wings i have in mind will carry that extra weight without problems.. ;)

@Jacques

Thanks! I'm definately interested in more silent fans! I don't know much about them and i dont know what it all means, (this is my first EDF project) but what I found on AEO units didn't sound very optimistic..:
http://www.rcgroups.com/forums/showthread.php?t=1398463
any comments..?

EDIT PS: and about the cuttig up of a baby's cup; I live in Amsterdam, and there's no RC hobbystore for miles around.. I have to use whatever i can find nearby. so I bought that one especially for its material and diameter.. -just like the legging, btw;)- just so you don't think I let my planes come before my baby.. :)

#5 derk May 04, 2012 05:51 AM

very nice, you can really hear the difference in the 2 setups. also, nice wing construction, i had not thought to cut a wing from an existing one.

#6 indoor_fr May 04, 2012 02:36 PM

Hi,

Very nice work on both wing and the edf!
Can't wait to see your bird flying!.:cool:

#7 Joe 1320 May 04, 2012 02:56 PM

Pretty cool. Are you going to use the stock canopy?

#8 4stripes May 04, 2012 09:43 PM

Great project!
Modelers that "think outside of the box" move this hobby forward.
I'm sure the composite crowd will have something to say about a foamy in "their section".
Keep up the good work,
Cheers Eric

#9 Robert Belluomini May 05, 2012 04:49 AM

Very cool! I have a Dutch friend in Helmond that likes to do stuff like this. Maybe you know him JePe

#10 Johannez May 05, 2012 11:06 AM

Quote:

Originally Posted by Joe 1320 (Post 21519393)
Pretty cool. Are you going to use the stock canopy?

...have you ever seen a gull using a canopy..? ;)

What gulls DO use however, is Fly By Wire. they constantly make minute adjustments because they really feel every breath of air which passes their wings..
So when I saw this 3 axis Gyro Flight Controller,
http://www.himodel.com/img_sub/rc_img/12/02/8629.jpg
..I thought why not..? for 30 bucks I can make my bird fly by wire too! :) (and I can always turn it off)

meanwhile, I've been pondering on how to fix that rotating tail.
again a plactic PET bottle came to the rescue, combined with a teflon-tape holder and a coctail stamper...:

http://johannez.nl/oud/content/images/460.jpg

http://johannez.nl/oud/content/images/461.jpg

http://johannez.nl/oud/content/images/462.jpg

http://johannez.nl/oud/content/images/463.jpg

..hope it will work..!

#11 vettster May 05, 2012 09:33 PM

Brilliant Work!!

#12 Johannez May 07, 2012 07:35 PM

Well, I've spend countless nightly hours trying to get the damn tail mechanism to work, or rather, to be easily workable by a servo... the pusch-rod had to be very small yet very strong, very felxible (going in a curve) yet precise, and durable yet moving real easily... everything i tried seemed to jam the mechanism and/or break. after many failed attempts and reaching near insanity, a hard plastic party drinking straw married a tiny tie-wrap, and they brought salvation!

http://johannez.nl/oud/content/images/465.jpg
now lets hope the .5 kg torque of HK's 3,7 gram servo's will be up to the task..!

I temporarely put some parts together..She's starting to look like a bird! :)

http://johannez.nl/oud/content/images/464.jpg

#13 Johannez May 09, 2012 05:50 AM

I'm coating the whole thing in "HEMA knutsellijm" (= cheap-ass hobbyglue), works really nice!
Its deludable in water, so i can just paint on a thin layer, and when it dries (takes a while) it leaves a completely invisible, waterproof skin. its strong but still flexible, and it allows the surface to be sanded REALLY smoothly..! Also it doesn't have that yellowish look to it, like woodglue or even uhu-por tends to have after some time.. I coated the servo compartments inside the wing extra thick, and there it shows an almost green/blue pearly quality.. and after sanding.. it just feels smooth as silk..!

these are things I can not show you on internet pictures, but I'm lovin it!

http://johannez.nl/oud/content/images/466.jpg

http://johannez.nl/oud/content/images/467.jpg

#14 bwoollia May 09, 2012 10:48 AM

Very interesting project! :cool:

#15 Johannez May 09, 2012 11:25 AM

coated all the parts with hobbyglue, they're almost done..! ready to start building in the elctronics. just waiting for that A3 Gyro flight controller and those damn servo wires ...

http://johannez.nl/oud/content/images/468.jpg
and to think this used to be a MIG 15... ;)

She's starting to look like she wants to fly..!
http://johannez.nl/oud/content/images/469.jpg


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