Micro 3D ? - RC Groups
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Oct 19, 2004, 01:49 PM
Sussex, UK
RobinBennett's Avatar

Micro 3D ?

Is there anything between small 3D planes (the smallest I've seen is about 24" with a CDROM motor, weighing 4 or 5 oz) and the sub-1oz micro planes (with pager motors and coil actuators)

Specifically I'm thinking of something that can loop and roll but not necessarily hover, for indoor flying where a small 3D plane would be a bit limited.

At the moment I'm flying a 24" depron mini ultimate biplane with a CDROM (but it's 6mm foam and weighs 7 oz). The goal is to fly in a 30 foot square school hall...
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Oct 19, 2004, 02:11 PM
Lance Armstrong- 7 times!
flybike's Avatar
Possibly a Mini Ifo?
Oct 19, 2004, 04:49 PM
Sussex, UK
RobinBennett's Avatar
That's a possibility, although at the top end of what I'd like; it certainly looks as if it could be flown in the space available. Are they available in the UK?

Is there anything smaller, or does conventional radio gear become impractical?
Oct 19, 2004, 05:26 PM
Sussex, UK
RobinBennett's Avatar
I think my question is "why is there a gap between the biggest actuator models and the smallest servo models" and how I'd go about building something like a mini ifo but lighter - say 2oz.
Oct 19, 2004, 10:31 PM
Registered User
phil stevo's Avatar

mico acro

This 10in Ultimate is getting close to your dream. It started as a bit plane with 6mm motor and rudder only, but now has R & E coils, JMP Rx, N20 motor and will loop and snap roll at 22g. It gained a lot of weight in repairs and modifications and because of its origin it has cambered wings and some incidnece between wing and tail, all of which make it stable and docile to fly. A new lighter one or a slightly bigger monoplane rigged 0-0-0 should be very nimble when I get around to it
Oct 19, 2004, 10:39 PM
Registered User
Oct 20, 2004, 12:05 AM
To many projects
66tbird's Avatar
Nice phil Stevo, that is the very directing I'm looking at also.

I built a high wing mono plane for speed (30 sqr.in)with a under-chamber foil to widen the flight envelope. At 24gr with a kenway 4.2 its to fast to snap, but the vertical is great. 5 seconds and its out of sight.

On to the question;

I feel it has to do with the airfoil needed for a 40-60 gram plane combined with current motor combinations available. I'm new to the sub-ounce field but what I would really like is a single cell BL in the 4-5 gram range with 50+ gr of thrust. Heaven with a prop But hey, it's new stuff for me still, and there are planes on this forum that sure are making the minds ideas start to turn.
Oct 20, 2004, 06:30 AM
Me likes Depron...
Pjotrrr's Avatar
Hi Phil,

Nice bipe
Can you give some details on gearing and prop used on that N20?
LV or HV N20?
Also: one or two cells lipoly (Kok145?)

Last edited by Pjotrrr; Oct 20, 2004 at 06:34 AM.
Oct 20, 2004, 07:45 AM
Sussex, UK
RobinBennett's Avatar
> This 10in Ultimate is getting close to your dream

It certainly is! What's it made from? 2mm depron? More details please!
Oct 20, 2004, 06:38 PM
Registered User
phil stevo's Avatar

10in Ult

More info for those interested.
I checked again and it is a M20LV not the slightly bigger N20. Not sure about gearing, I think it is a 12 tooth didel pinion and the spur gear is probably from a 24hr timer with about 75 teeth because it is bigger than the didel 60tooth. It runs on a single 145kokam through the JMP combo. Prop is GWS 5030 or close to it. Have not measured current but it draws down the cells enough to ruin flight performance in about 5minutes, depending on throttle use (no where near 3v though) so it is probably is up around the amp.
The model is mostly 2mm depron. I sand the wing and tail surfaces slightly airfoil and curve the wing panels over the edge of the bench. The fuse originally has a 10mm wide strip of 1mm balsa each side for stiffness, but after the fron broke of several times I made the box section fuse front to contain the motor, Rx and battery.
There is another post on this model in working pager thread. Sorry it looks a bit rough now but it has had a hard life.
Oct 20, 2004, 08:45 PM
Hey y'all... watch this!
Rex A Lott's Avatar
Here's my Acrobipe from UBHobbies
GWS EDP with 0303 prop.
GWS pico Rx
GWS pico servo's X 2 (no rudder servo).
iRate 2s 300mAh 10C Lipo batt

AUW = 3 oz 86g
WOT = 1.5 A
WingSpan = 15"

Build info:
Use a very sharp xacto blade to cut away the top engine cowl and large section mid-fuse including pilot. These fuselage parts are now held in place with some extra rare earth magnets left over from CDROM coversions. Using aileron arms for control horns, servo install is easy. Use masking tape to remove yellow paint on wings.

Flight report,
Yippeeeeeee! I think my plan to use big ailerons (bottom wing only) helps this little guy fly slow. It flies great. One more final CG check and I gave it a toss over tall grass expecting the worst and off she went just as straight and smooth as could be. A couple clicks on the trim and hands off flying was achieved on the first flight. By the end of the 1st full battery charge I had accomplished several rolls, loops, hammerheads. ROG launch and landing, some touch and gos, and several uneventful crash landings into the short grass of a baseball diamond including a couple cartwheels. Full throttle climb is a bit less than 45 degrees but very healty just the same. I estimate stall speed (SWAG) to be about 5 mph. It's a very nice and slow flyer.

Every battery change requires re-trimming the model due to slight CG changes. This bipe is very short coupled and small changes in CG make a big difference in the air.

My battery choice allows me to put the battery inside the fuse. This is not possible with the Kokam 340mAh which is slighty too big. It sure is cute in the air. My co-workers were astounded watching it fly.
Last edited by Rex A Lott; Oct 20, 2004 at 09:17 PM.
Oct 20, 2004, 08:59 PM
Hey y'all... watch this!
Rex A Lott's Avatar
So originally you were asking for a 3D capable plane. Me too.

Notice in the last photo there are two. The one in the foreground with the grey propeller is still stock. My next project is to convert it to full 3D 4-channel plane with a home modified 20mm CDROM motor.

I looked around for quite a while and decided to work backwards. The weight of the "smallest 3D plane possible" is relative to the components you put into it. I want full proportional servos (not actuators) for 3D. There are some servos that weigh a bit less, but the GWS pico servos are a good price / weight / performance tradeoff. Now you need a battery, an ESC, and motor.

In the combo above, all the electronics (without the plane) came to ~ 3 oz or just under 60 grams. Based on that, a 15" wingspan is a bit small since I'm hoping for something that's still slow enough for indoor flying. A bipe is a good choice providing more wing area. The combo above is quite easy to build with the GWS motor and it's a hoot to fly with good climb rate, but certainly not 3D and no rudder.

I expect the 3D version will come in at just over 4 oz which will stall faster. It will have a Kokam 340 20C lipo, 3 servos, and small CDROM motor. It should be a fun winter project. Right now I'm experimenting with using the stock propeller and spinner on a CDROM with ~27 turns. Results are promising if I don't overload the lipo's and explode in mid-air.
Last edited by Rex A Lott; Oct 20, 2004 at 09:03 PM.
Oct 20, 2004, 09:26 PM
Registered User
This plane has been seen here in the micro thread before but since the question was asked about a plane that fits between the large and micro sizes I thought I would show it again. This is a full 3D plane. It will do just about anything you want it to do including hovering. It weights 41.7 grams without the batteries. I fly it with two 250 ma lith-polys. The motor is my own 7 gram brushless with a 6x3 prop.

There is another 3D plane that Bob Selman sells as a kit using the N20 geared. It will hover also. It is a new kit that Bob has just started to sell and I think will be reviewed in RC Microflight mag in the near future.

Oct 21, 2004, 11:23 AM
Live to ride... and fly!
Tres Wright's Avatar
Gary, great looking micro! Very cool! What are the dimensions?

==There is another 3D plane that Bob Selman sells as a kit using the N20 geared. It will hover also.==

I saw it at DEAF and it does indeed do 3D flying. Any 3D plane is going to require servos rather than actuators, and will require at least a 4 channel receiver, so there are limits on how small one can get for now. I think Gary's 42g + battery is about as light as a 3D plane can be with current technology.
Oct 21, 2004, 11:31 AM
Live to ride... and fly!
Tres Wright's Avatar
Here's the one that Selman offers:


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