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Nov 03, 2007, 10:20 PM
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Angry_Monk's Avatar
Discussion

560mg Plane


Here is my new 560mg plane. After building a couple sub gram planes i figured i should get my act together and build one with lightened 3.2mm motor. After several attempts at rebuilding the motor i finally got one that was light (130mg) and also powerful, devolving 450mg of thrust with Martin's Shicoh prop (courtesy of Robert). the motor could be 20mg lighter but i added some meaningless steel to it which i thought would increase magnetic flux, turns out i was wrong... i plan to still experiment with lightening these motors and see how light i can get them.

First test with this plane ended with it on the ground 2 ft in front of me with a broken fuse stick between the battery and RX.... caused mainly by the nose-first impact it had just suffered. luckily the fuse stick was all that was broken and could easily be fixed. sadly the motor's brushes got messed up from the crash and caused the plane to lack enough power to sustain altitude. i played around with the brushes and eventually got the motor running better again. i went to test the plane again and almost had a heart attack when it climbed like a bat out of hell after i let it go. this plane has so much power! much more than my other sub gram planes. although it is very fast for a plane with a 2.75" WS. i need a small gym to fly it comfortably. i would not do figure eights in my church where i usually fly my planes, to risky for me. although the up side is that it flys, and very smoothly at that!

i will post more pictures tomorrow and a video. comments are welcome.

Specs:
WS: 2.75"
Actuator: 3mm ID, 160ohms
Motor: lightened 3.2mm Shicoh

Component Weights
Airframe + Actuator: 45mg
IR RX: 50mg
Lightened 3.2mm Motor: 130mg
Prop: 20mg
8.5mAh Li-Po: 295mg
misc: 20mg

Total: 560mg

Video: https://www.rcgroups.com/forums/show...63#post8487767

Some pictures for your enjoyment:
Last edited by Angry_Monk; Nov 13, 2007 at 10:10 PM.
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Nov 03, 2007, 10:42 PM
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shockflyer12345's Avatar
Nice job!
Nov 03, 2007, 11:14 PM
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Martin SJ's Avatar
Hey Monk, that is TERRIFIC! Congratulations!! It is amazing how well these things fly once they get below 700 mg. My 600 mg plane did something similar to your plane, and just before it hit the ceiling of the gym I cut the throttle, which put it into a spin. The motor hasn't been the same since.

And you say you can remove more weight?! That's getting really close to 500 mg ...

--Martin
Nov 03, 2007, 11:38 PM
No more nicotine for me!
micro_builder's Avatar
that is quite excellent, and so close to that magic number!

very nice work, congrats!

nick
Nov 04, 2007, 12:19 AM
I forgot the transmitter!
gguy's Avatar
Looks nice! I gotta get me some carbon rod so I can build a few light models!
Nov 04, 2007, 12:34 AM
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Angry_Monk's Avatar
Thanks for the comments.

i've done the math: if every part of the plane is just light enough a sub 500mg plane can be built with current parts, but just barely. of course, this means finding out how Koichi built his 35mg IR RX...

Martin: the reason it really flies so well is because of your prop, so thanks for indirectly giving that to me! when i get my CNC done i hope i can start milling my own props and experimenting with different designs.
Last edited by Angry_Monk; Nov 04, 2007 at 09:59 PM.
Nov 04, 2007, 12:39 AM
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mcm1303's Avatar
That's great Mr. Monk!

Interested in the prop. What weight of cloth is that? Does the final prop have the full weight of the original fabric, or is much of it sanded/machined away to get to the final product? Vacuum bagged? Type of resin?

I've always liked the look of the raw CF weave.

Marlin
Nov 04, 2007, 04:44 AM
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kimhey's Avatar
SCARY.....

Kim
Nov 04, 2007, 05:39 AM
Team30 Micro EDF
NitroCharged's Avatar
Wonderful stuff Monk. How hard is it to see when it is near the ceiling or far away?
Nov 04, 2007, 07:40 AM
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CA'ed fingers's Avatar
Man, words fail me...
Nov 04, 2007, 09:42 AM
The ceiling is the limit!
micromad's Avatar
Wow magic stuff Monk. Could you explain how you got the motor so light?

many thanks

Alex
Nov 04, 2007, 10:23 AM
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Angry_Monk's Avatar
mcm1303:
the prop was actually made by Martin, so he would be better at explaining the details, but i think i can cover your questions. the carbon cloth is 2.44 oz/sq. yd and the resin used is west systems epoxy, all from: http://www.cstsales.com/. the final weight of the prop is the cloth + epoxy, very little sanding is actually done to reduce weight as far as i know. i believe the way these props are formed is over a mold which is then placed inside a heat shrink tub. the tube is then shrunk providing the pressure needed to get a nice clean prop.

NitroCharged:
you can see it quite well, actually. i havent had it that far away, maybe 20-30ft. its not like you are straining to see it, or pick out its orientation. since circles are all you really do with this plane you usually know exactly which way its going. it looks like an oddly fast large insect.

micromad:
the motor was the trickiest thing to build. to get it that light you need to only use the necessary parts: brushes (bare), commutator, and magnet (bare). you need to get the brushes out of the plastic end cap, get the axle out of the commutator, and get the metal tube out of the magnet. there is also a Teflon and brass washer in the commutator that need to be taken out, i replaced them with a ruby bearing for better friction management. i reduced the diameter of the axle to .25mm using a steel rod i had around, and made the bearing for that out of .002" brass shim stock, so the axle would fit in the magnet. by doing all this you can get the motor close to its bare wight, which is about 110mg. that is the mass of the commutator, brushes, and magnet. by adding a smaller axle, brass bearings, and some other small parts a motor below 120mg can easily be built. Robert has some good info on this: https://www.rcgroups.com/forums/show...t=584505&pp=15
Last edited by Angry_Monk; Nov 04, 2007 at 10:31 AM.
Nov 04, 2007, 02:33 PM
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Angry_Monk's Avatar

Video


just went down and got a couple videos of the plane. the one i posted was the first, i flew for two more longer videos after that and then for a bit without being filmed. this thing has some duration! i was very surprised. also, here is a nice closeup of the electronics. if anyone has any picture requests let me know.

Video: https://www.rcgroups.com/forums/show...63#post8487767
Nov 04, 2007, 03:56 PM
Registered User
Martin SJ's Avatar
Monk, You are right on all facts about the prop. Glad it worked for you.
Nice video! Now, about turning right ...
--Martin
Nov 04, 2007, 04:25 PM
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Angry_Monk's Avatar
Quote:
Originally Posted by Martin SJ
Now, about turning right ...
--Martin
yeah.... i'm working on that. i think the rudder doesn't quite have enough throw in that direction for some reason. maybe too much area. its something i'm working on.


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