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#1 knlever Mar 21, 2010 07:15 PM

Micro EDF Free flight Project
 
The sight of a free flight model sailing along under power can be very entertaining, even for a short flight in a combined space. Better than a glider.

My project is to build an EDF model like this:

http://www.rcgroups.com/forums/showt...1186170&page=4

I m confident in building the airframe.

Of course I can convert it to RC later. Just add the receiver, batt, servos etc right?

What power source and motors do I need?

:D

#2 Vic Arcudi Mar 21, 2010 08:03 PM

If you're not dead set on a Mig, Today's hobbies produce some great f/f scale jets: http://www.pennvalleyhobbycenter.com...4ephantomt.htm
As for power, there's a great little 32mm fan by K&P, sold thru SAMS models or direct thru Knight & Pridham: http://www.kpaero.com/ProductReport....gory1=electric

#3 knlever Mar 22, 2010 12:42 AM

914 DF 32 Ducted Fan Ý32 mm. £ 28.50

Ducted fan with motor would be good.

What about the battery shown here : Ni - MH

http://www.hobby-lobby.com/easy_fly_...85636_prd1.htm

I laready have a CDROM motor

#4 Vic Arcudi Mar 22, 2010 02:26 AM

The fan you quoted already has a Feigao inrunner installed. As for batteries, you'd definitely have to get a Li-Po pack, anything else is simply too heavy. A CDrom motor is fine if you intend to build an r/c pusher.

#5 JetPlaneFlyer Mar 22, 2010 04:40 AM

Knlever,
The Mig is mine. Iím delighted thatís itís inspired you to try something similar.
While doing my research for the Mig I tested several fans/batteries/Escís etc. What Iíve ended up with for initial flight testing (it flies well by the way) is this set up:
You will need a pair of M1.4 x 2mm long screws to mount the motor plus the various electrical connectors.
This will give you about 55g thrust which is plenty for a freeflight model of similar weight to the Mig (about 90g all up). Higher thrust options are available. The KP fan is good but is a bit heavy (27g compared to 10g for the one I listed above)... The KP fan will run on three cells though which puts thrust up to 130-140g.
The other option is one from the range of AEO fans. Iíve tested a few of the AEO fans, the 30-10 model produces an impressive 80+ grams on two cells: http://www.aeorc.com/english/?product-265.html but needs a 10 amp rated ESC and battery.

By the way.. the Mig 17 laser cut kit and all the electronics will soon be available from Shortyís Basement: http://www.shortysbasement.com/

Steve

#6 JetPlaneFlyer Mar 22, 2010 04:53 AM

PS.. the F4 Phantom linked previously by Vic looks like a very nice model but it's really intended for static display and so has no provision for power source and looks also to be built too heavily for flight. it would need considerable modification if it were to be converted for EDF.

Also regarding modification to RC 'later'.. This would be very hard to do because provision needs to be made during building for the servos, wiring, pushrods etc.. fitting these in after the model was finished would be very hard to do because there is not much room on these micro sized models.

Have you built balsa stick and tissue models before ?.. It may look easy but a scale jet is not the best subject if you dont have much building experience... They are not actually as easy to build as they may look

Steve

#7 shin Mar 22, 2010 10:22 AM

Hi
Subscribed:D
Look here for inspiration tips and info on building a F/F scale jet
http://www.ffscale.co.uk/f84.htm
Main site tons of good info to be found
http://www.ffscale.co.uk/
Take care
Hank

#8 JetPlaneFlyer Mar 22, 2010 01:04 PM

1 Attachment(s)
Mike Stuart's ffscale website is a great resource. You can download freeflight jet plans from there in the plan download section. Some are Mike's own design a few are mine. They are intended for Rapier rocket power but some could be converted to EDF.

Here is a snap of all the components you need for a brushless micro EDF freeflight set up...

#9 vintage1 Mar 22, 2010 01:21 PM

we've had good, if expensive results off GWS small fans and 12mm inrunners. Forget the GWS motors though. One flight if you are lucky.


KP aero do some small ones as well. Not sure what kind of motor is in them.

#10 vintage1 Mar 22, 2010 01:22 PM

Quote:

Originally Posted by Vic Arcudi (Post 14656875)
If you're not dead set on a Mig, Today's hobbies produce some great f/f scale jets: http://www.pennvalleyhobbycenter.com...4ephantomt.htm
As for power, there's a great little 32mm fan by K&P, sold thru SAMS models or direct thru Knight & Pridham: http://www.kpaero.com/ProductReport....gory1=electric

Hey C'mon Vic. We sell that as well!

#11 JetPlaneFlyer Mar 22, 2010 02:48 PM

Quote:

Originally Posted by vintage1 (Post 14662604)
we've had good, if expensive results off GWS small fans and 12mm inrunners. Forget the GWS motors though. One flight if you are lucky.

Vintage,
unless you are willing to do major transplant surgery on the motor mount the GWS EDF30 needs a 10mm motor, which until recently was a big problem because ther were no 10mm motors available that would give decent performance. The little Turnigy 1015 hopefully solves the problem though it does run very hot on two cells (it's designed for single cell Lipo batteries)

The GWS 40mm and 50mm fans will take 12mm motors and perform really well... it's probably these that you are thinking of

Steve

#12 knlever Mar 22, 2010 07:08 PM

Vic,

The CD ROM motor options sounds interesting to me. What sort of prop do I need? Also what is the weight of a Li-Po versus a Ni-MH battery, the latter are more readily available.

Will 3V Ni-MH work?

#13 knlever Mar 22, 2010 07:11 PM

The Turnigy looks like a nice motor. Does it need an ESC? Also how rugged are these motors I don't want to burn one out every week or so!

Will it run with a NI-MH?

Spec.
Battery: 1 Cell 1S/3.7V
RPM: 11500kv
Max current: 4A
No load current: 3.7V/0.4A
Current capacity: 4A/1sec
Internal resistance: 0.51ohm
Dimensions: 10x15mm
Weight: 5.1g (kv11500) (not including connectors)
Diameter of shaft:�1mm
Length of front shaft:�5mm
Suited for Mini EDF or micro brushless cars.

#14 knlever Mar 22, 2010 07:12 PM

Very nice site. Thanks

#15 knlever Mar 22, 2010 07:19 PM

Jet Plane Flyer

Yes I build one Guillows ME 109 some time ago. It was the most fragile thing I ever saw. Not having covering paper I used plastic covering. It actually flew but hit an obstruction and crashed. I only have the cowl and the canopy now.

I also built a foam Hasegawa rubber powered spitfire - available in the UK in around 1991 or so - best model I ever flew - easy to trim and great flights.

I really want to try something other than balsa - will keep you posted.

I really don't want to get into burning money at this stage. I have a CDROM motor, and NI-MH packs are readily available and cheap. Maybe I should build my ducted fan.

Just want to see if the design will sustain itself in flight for a few seconds. Once that is done I can progress. Luckily we have air around where we live :)


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