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Old Oct 21, 2008, 05:13 AM
Crash Test Dummy
Cambridge, England
Joined Jul 2008
127 Posts
Discussion
Homegrown sub-micro Brushless CP Heli Kit

This is probably stupid idea but I am going to say it anyway.

I quite fancy the idea of building a sub-micro heli from a kit of fairly common parts.

I was thinking of a 1s solution that is DSM2 compatible. Probably based on one of Marios airframes with a modifed "theSteve" AR6300, gyro, ESC's and either a 4G3 CP head or similar.

This would take me a fair bit of time and investigation to get all the appropriate parts together, and a lot of separate shipping charges no doubt!

I was wondering if anyone like theSteve or John etc. who have already probably done this would put together and sell a kit of all the necessary parts with a clear price?

I am not sure if anyone else thinks this would be a good idea, but it could certainly tempt me from the 4#3B onto a brushless DSM2 kit build.

So is it a stupid idea or worthwhile? Would anyone else be tempted by such a kit?
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Old Oct 21, 2008, 05:26 AM
Fly, fix, repeat
oobly's Avatar
Tampere, Finland
Joined Feb 2007
961 Posts
I think Mario would be the guy to put something like this together. I think 1s isn't practical for a kit. With 2s you can use almost any off-the-shelf electronics as long as it is small and light enough. You can get some very nice small 2s packs (200 - 350mAh). Also, you have more choice in motors and ESC's.

I wish I could find a really small CP tail unit or at least premade parts for one. Then it would be pretty easy to supply a full belt or shaft tail CP submicro kit using 4G3 parts!
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Old Oct 21, 2008, 05:45 AM
Crash Test Dummy
Cambridge, England
Joined Jul 2008
127 Posts
The main reason I was thinking 1s was because I know there are working 1s systems now and I have a few 4#3B LiPo's already. I would certainly consider a 2s solution if the same supplier could sell them at a great price too.

I guess the other reason I was thinking 1s was because the whole thing needs to be very small and light. I am thinking 4#3B or 4G3 sizes.

I did see that Mario apparently does this sort of thing, but I am not aware of any kits like this that he does.
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Old Oct 22, 2008, 11:50 AM
Registered User
United States, CO, Vail
Joined Apr 2008
69 Posts
Look at his (Mario's) Bumblebee kit. I ordered one and havent finished it yet. An esc for the brushed tail has been a PITA to find. I have been working on other projects and it's pretty much sitting on a shelf right now. If I did it all over again, I'd look at the BB Frame and build with brushless parts to finish. It is double the size of a walkera but would most likely be twice as stable too.

FWIW
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Old Oct 22, 2008, 08:10 PM
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MarioIArguello's Avatar
Joined Jun 2006
1,421 Posts
MIA BB For 1 cell Operation - Slow Flight Heli.

Quote:
Originally Posted by Henry Bowman
Look at his (Mario's) Bumblebee kit. I ordered one and havent finished it yet. An esc for the brushed tail has been a PITA to find. I have been working on other projects and it's pretty much sitting on a shelf right now. If I did it all over again, I'd look at the BB Frame and build with brushless parts to finish. It is double the size of a walkera but would most likely be twice as stable too.

FWIW
Here is the MIA BB thread that has a a good amount of information about the kit , its updates and some videos of people flying it and moding it.
http://www.rcgroups.com/forums/showt...ghlight=MIA+BB

Also look at the videos on my You Tube page and on my site. My videos show the heli flying all stock. Note how smooth and slow the helicopter flies
with the stock motors and lightweight electronics.

Over time I have tried to simplify the Bumble Bee design to work with direct drive and a small tail prop, this is what I supply in our most recent "builders' BB Kits" I've also made additional G10 parts that hold the blades in a special way so to allow blade pitch setting without the need for the balsa wedges we were supplying with our "MIA Universal Flat Bottom Wood Blades", before. Now the blades have a more lean and clean appearance and the heli performs even better, with these changes.

With any heli there is always a catch or preference how it flies better and the MIA BB also has its preferences.

Most of the helis I've designed and sold in kits come from the idea of keeping the helicopter as light as possible. I don't like heavy helicopters unless they are large scale models in which the added weight may favor such.

For example the 2000 MIA Robin 280 kit was lighter by 4 oz from any standard similar size- micro heli of the same era and thus the House FLY, Bumble Bee, and most of my other heli designs follow this approach.

Unless you are looking for total efficiency and additional reduction in weight, I recommend that you start with the stock motors first, if you have a BB or looking to experiment with it a little. Get a good feel for the heli flying with stock motors and recommended electronics, then upgrade to BL.

Do not use heavy BL motors and do not use heavy batteries, the lighter you keep these components, the better and more manageable the helicopter will handle, particularly for first time pilots, assuming you want to fly it indoors or in calm weather. Follow all my tips on the ball links and how to make these linked joints very smooth. It is super important to get the rotor head and control links to move smoothly an d when you do, control of heli becomes more precise. If you don't, then you will have a hard time with the control, this is an area that some new pilots confuse with poor performance of design when indeed, all that is required is to get the links to operate as smooth as possible. Keep this in minds.

Read my guide at my site under Information it has some key points that may also help.


OK, now for a 1 cell operation Bumble Bee Size Helicopter.

The BB works very well on 2 450 -600mah li-po with the stock gear ratios and the stock 180 and N30 motors, in direct dtail drive. A 3 Cell-450mah also works nicely, anything above this with the stock motros will be unnecessarily heavy. It will also work on 1 cell 450mah li-po with mods to existing 1 celll 4in 1 controllers such Walker 4#3 and using motors wounded for ~ 3 volts DC , high current pull, operation.

Note that Power=IxE (Current x Voltage)

For a given power requirement, if you want to use low voltage the current must compensate (be higher) to give the power required, as power is the product of both. Keep in mind also that the rotor must spin at a certain speed to lift a given overall weight so KV of motor, gear ratios also plays an important role.
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Old Oct 29, 2008, 02:59 AM
Fly, fix, repeat
oobly's Avatar
Tampere, Finland
Joined Feb 2007
961 Posts
I will try a 2s setup with the belt tail CP submicro frame I have designed (and am currently building) after I get the 1s working. It could serve as a prototype for a kit, but the biggest problems are finding parts for the variable-pitch tail prop and finding a suitable belt. A possibility is to do what U.S.U.L. has done and use tiny mitre gears and shaft drive, but the VP tail problem still exists. In fact, you may just want to order one of his 60g submicro CP heli kits when they become available ;D

http://www.rcgroups.com/forums/showthread.php?t=871709

Getting closer to production, he is deciding on kit configurations already.
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