Espritmodel.com Telemetry Radio
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Old Sep 16, 2002, 12:54 AM
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flytowner's Avatar
Texas,USA
Joined May 2001
617 Posts
Super sub-micro airplane utilizing guts and radio from a Tomy Bit car...

Has anyone built a SUPER small airplane using parts from a Tomy Bit car? I've read that these little things can run 5 minutes on a 45 second charge (one cell NiCAD)!

Seems like it might be pretty easy to remove the 2CH micro Rx, motor, and battery and drop them into a tiny airplane to be flown in the house using the supplied Tx. You could use the two channels to drive a couple of small actuators for the tail feathers. The motor could just be wired for on/off control. I think you could literally fly a paper airplane with this setup. The problem might be finding props small enough...

Prices seem to be coming way down on these little gems: http://cgi.ebay.com/ws/eBayISAPI.dll...tem=1766233625

I think I'm gonna get a couple of these babies. One to play with and one to dissect!
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Old Sep 16, 2002, 03:52 AM
Stuck on a rock
epilot's Avatar
Faroe Islands, Sandoy, Sandur
Joined Nov 2000
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Slight snag with these - the range is very short. I also think that there is not power enough for flight on only one cell.

I think this has all been discussed before.

They are great fun to drive though - I have several.

Michael
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Old Sep 16, 2002, 04:53 AM
Sticky Shepherd
Graham Stabler's Avatar
Oxford/England
Joined May 2001
4,017 Posts
However you can whip out the one cell and replace it with a LiPoly, this does have enough volts and weights the same. I did this with an actuat car and boy does it move.

Michael is correct on the reange front although it is possible to boost the power of the transmitter by using 4 nicad cells I think. This has been done on the canned heat stuff but not sure about the bitcharger. There is a japanese site with a full conversion of a bitcharger but I forget the web address.

It also struck be that the actuator drive on these things is perfect for a mw actuator as built by Matt keenon and shown in RCmicroflight. Either that or use the origional coils. Would be good enough for guided FF.

The supplied motor might be ok for flight using a big enough gear ratio but I don't know, the Japanese guy used a geared KP00.

Graham
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Old Sep 16, 2002, 07:31 AM
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drliu's Avatar
Joined Jun 2002
269 Posts
It should be possible (indeed it has been done before, as reported on some Japanese web sites). The Bitchar-G motors are the largest motors I use to fly now and as a nice benefit come in many different speeds. They are definitely powerful enough if your plane is light enough. I usually gear them 1:16 now with a 160 x 120 mm prop from Westec. I've also used a BitChar-G motor geared 1:5 and flown with a much smaller U80 prop (less power but looks better), and geared 1:21 as well with the 160 mm prop (comparable performance).

The radio, however, is not proportional. You will get off/on throttle control, and left/right/neutral steering. There is a new generation of Tomy BitChar-Gers with 2 speeds if I remember; they might be more promising. Also, the radio is small, but not that small. I would be surprised if it weighed less than a RFFS. The actuator coils are not really well-suited to BIRD-style actuators. In the cars they are more or less simple electromagnets and affect steering by simple attraction rather than by rotating an magnet held within the coil.

Still, for about $20-40 it is a pretty attractive project.

-David
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Old Sep 16, 2002, 09:18 AM
Sticky Shepherd
Graham Stabler's Avatar
Oxford/England
Joined May 2001
4,017 Posts
I think the receiver something like a gram, I aggree the coils supplied aren't the greatest for lightness etc. You could wind your own, if you do it with two wires on the same former yuo end up with one coil that is actually two and you can mount them BIRD or RFFS style. The best bet might be bang bang for a rubber powered model or a simple outdoor model you guide away from the trees.

Muscle wire is a definate option.

Graham
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Old Sep 16, 2002, 01:14 PM
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Leicester England
Joined Jun 2001
591 Posts
Just play with the cars and

use a Z Tron proportional IR system for the plane

You can save a lot of weight if you leave out the voltage booster and circuit board. Use a Li poly cell and one low voltage senor, 150 Ohm coil a the smallest neodium magnet ....

Costs nothing, weighs nothing !

Power the plane with a geared pager and ultra thin prop?
Make all of the plane from 2mm wall foam,shoudl weight 10g at most? Save a bit more weight by using a Muscle Wire actuator, Matt is working on an IR Rx with special centralising software.


Its a great time to be an aero modeller!

Mark

(I was thinking of doing a 9" span B17 as above design)
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Old Sep 16, 2002, 06:12 PM
lrc
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UK
Joined Aug 2002
15 Posts
I found that the range on the BitChar-G receiver can be increased by increasing the ariel length, up to 50 metres or more with a 100 cm ariel, although this becomes less when it is coiled.
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Old Dec 20, 2002, 01:33 AM
My cat up close
bipeflyer's Avatar
England
Joined Feb 2001
4,021 Posts
How about this then?

Take a look at this:
http://www.rcgroups.com/forums/showt...threadid=79154
Yes,a six motor micro car gut conversion EDF An-225......Amazing!
Matt.
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Old Dec 20, 2002, 03:58 AM
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Amersfoort, The Netherlands
Joined May 2002
352 Posts
You should read this thread:

http://www.rcgroups.com/forums/showt...threadid=79245

Edit: It describes how to get a range of ~250 feet!

Jan-Dirk
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