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#1 boredom.is.me Sep 05, 2012 11:22 AM

12" Isis G2 UltraLight
 
3 Attachment(s)
I already have a newer version designed, but I have this sitting down so I decided I should build it for our upcoming fly-in (Nov 4 - ERAU Daytona). Now I am wondering what electronics I should use. I have two .675g servos and an AP02 (actually four of them). However I do not want brushless, for simplicity, and because brushed is lighter and nearly as powerful. I was thinking of a geared 6mm. What should I use for control, servo or actuator?

Attachment 5134402Attachment 5134403Attachment 5134404

#2 nemoskull Sep 05, 2012 02:31 PM

blah blah blah.

edit:
you still have the ap-02?

whats the thrust on those, anyways?

i say actuators, mostly cuz its not done any more and in a modern 3D style plane it would set you apart from teh crowd. servos might be more precise, tho.

#3 boredom.is.me Sep 05, 2012 02:57 PM

Yep I still have all four. If I'm correct, I believe they do about 20g, but I have no presentable data of this. That is just what I got from what some have said.

I like the actuator idea, but since my first RC experience, with Plantraco, I've been scared to use acts. Still not over that fear...
As far as weight is concerned the servos are the lighter option, but there is a bit of fiddling that I'm not up to at the moment...

I am considering servos for the aile and elev and a .4g actuator for rudder.

#4 boredom.is.me Sep 05, 2012 03:10 PM

AP02 Thrust Data
Prop - Current - Thrust
2.5x0.8 - 0.9A - 19g
3x2 - 1.8A - 27g

from micronradiocontrol.co.uk

Considering that I would still need an esc, this would be a heavy option at about 3g for the propulsion. On top of that, it would be an amp hog at constant full.

#5 boredom.is.me Sep 05, 2012 04:33 PM

1 Attachment(s)
I swear by Foam Tac, but I am wondering if I should use foam safe CA instead.

I removed two lower ribs and one upper rib. They aren't necessary at this size.
Attachment 5134965

#6 Free Sep 05, 2012 05:05 PM

Amazing!:)

What's your planed AUW?

Free

#7 boredom.is.me Sep 05, 2012 05:11 PM

1 Attachment(s)
Thanks,
I honestly have no idea. Would you say the airframe seems a bit heavy? I'll be shooting for 12g.

I'll be using 2um mylar and .5mm carbon control rods and fuse braces.
Attachment 5135042

#8 minimicrorc Sep 05, 2012 06:26 PM

are you using a deltang receiver?

#9 I R Irv Sep 05, 2012 07:08 PM

If you come out at a 12gr AUW a 6mm GB should work fine. Get the J3Cub motor/GB, your new found 101mm CF prop and run them with a Hyperion 70mah battery. I would also stick with the servos.
TODD

#10 boredom.is.me Sep 05, 2012 07:46 PM

Quote:

Originally Posted by minimicrorc (Post 22651791)
are you using a deltang receiver?

Most likely

Quote:

Originally Posted by I R Irv (Post 22652156)
If you come out at a 12gr AUW a 6mm GB should work fine. Get the J3Cub motor/GB, your new found 101mm CF prop and run them with a Hyperion 70mah battery. I would also stick with the servos.
TODD

I was considering a custom 4:1 or 5.3:1 gearbox with the same Cub motor. Does anyone know the Cub's ratio? The Cub had some bad prop shaft issues too.

I'll keep the LZ .675g on aile and elev. But that still leaves rudder. I can't afford the newer .48g bearingless version so I might just go with a MicroAct. The thing is that I doubt the Micro act has the torque needed for proper rudder control.

Oh and the 70mah might indeed be a better option, but at the cost of an extra .5g which.

#11 boredom.is.me Sep 05, 2012 09:03 PM

2 Attachment(s)
I ordered the Mylar, made/assembled the aileron bell crank, and cut a slot for the aileron servo.

Now I'm wondering if I should locate the aileron related control hardware on top of the wing or under it. I remember running into space issues with my larger one, but I really do not think that will be as much of an issue now since I don't have an esc either...just rambling. I'm really just thinking about the final apparence.

Attachment 5135596Attachment 5135600

#12 nemoskull Sep 05, 2012 10:15 PM

on top the wing would run less risk of damage in case of a bad landing or crash.

#13 I R Irv Sep 05, 2012 10:22 PM

I'm pretty sure the Cub GB is 4:1 just like the Ember. That's why I suggested the CF prop, with a prop savor you'll never break the shaft especially if you screw the savor past the end of the threads.
TODD

#14 boredom.is.me Sep 05, 2012 10:56 PM

Quote:

Originally Posted by nemoskull (Post 22653814)
on top the wing would run less risk of damage in case of a bad landing or crash.

Top mount it is.

Quote:

Originally Posted by I R Irv (Post 22653869)
I'm pretty sure the Cub GB is 4:1 just like the Ember. That's why I suggested the CF prop, with a prop savor you'll never break the shaft especially if you screw the savor past the end of the threads.
TODD

Good to know. I'ld like to try a bearing-less gearbox. There is less resistance with smaller shafts. I'll also use a carbon rod for the shaft. A didel 9t and a 36t .3mod is the choice. I'll get the prop saver too.

#15 nemoskull Sep 05, 2012 11:35 PM

the 6mm motor in the HK gearbox is(was?) a 3.3 ohm model. back when i was running DD 6mm planes, the HK motor was noticablely more powerfull than the didle 4.5 ohm.

where do you get you gears from, BIM?


edit: now you got me all wanting to make small planes again!


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