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Jul 18, 2005, 04:28 AM
Registered User
Thread OP

RotHeli1: 9" RC UFO DIY project

Hi all!
After the microheli4 project (, this is my new DIY project : RotHeli1 (photos below)
This is an All Rotating Aircraft concept that is fully controlable.

The platform is based on "Vectron ultralite" saucer (steven davis patent, good idea steven!) that you can find at your local toy store. This saucers are very stable in hovering but you only have 1 channel (up-down). Id like to make it fully RC with 4 channels like a normal Heli.

To achieve this the first step is to put an electronic compass and a PIC to resolve the first problem (where is the heli pointing?) and a LED to indicate where is the heli "virtual tail". This resolve the orientation problem...
The second big problem is how to move the heli? The answer is an stabilization bar (really a desestabilization bar...) that is controled by a magnetic actuator and the PIC. If you change the angle of the stabilization bar in the same point on each revolution of the body you get (90 later) a move of the heli... Ok this is a simple explanation...

RotHeli1 specs :

- Lenght(Diameter) : 23 cm (9")
- Height : 13 cm
- Total weight : 79g
- Body construction : Depron, balsa & 2mm Carbon rods
- Battery : LiPo 250mAh
- Battery life : about 10 min.
- Rx : Schulze Alpha 4 (without case)
- Motor : 1 x GWS LPS 5:1 (RXC motor)
- Prop : GWS 9x4.7 cutted to 8.5x4.7
- Servos : NO
- Stability : Self-stable
- Gyro : NO (the compass works as a heading-hold gyro)
- Actuator : 1 x Magnetic actuator (coil + magnet)
- Functions : 4 (Throttle, Roll, Pitch and Yaw)
- Electronics : home made electronics
- Compass module : magnetoresistive sensor + OPamp
- Procesor : PIC 16F876
- Price : This is a cheap project (the most expensive component is the electronic compass at about 20$)

I could say that this "thing" is very stable in hover and you can control in all directions like a normal heli. This first version is a little lazy to move buy i am working on this...

Id like to know how do you think about this project and new ideas/question to improve it. I can post more info if you want. I am now working on a version 2...

Here are some photos.

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Jul 18, 2005, 08:50 AM
Pro Bro #495
fwilly's Avatar
Wow!!! Thats awesome!
Jul 18, 2005, 08:55 AM
The ceiling is the limit!
micromad's Avatar
Wow that looks complicated.
Jul 18, 2005, 10:59 AM
Thats NOT indestructible
j8m8l's Avatar
Amazing project!
Do you have any flight videos?

Jul 18, 2005, 11:06 AM
derk's Avatar
thats cool 4 channels, one actuator. thats awsome.

how did you get it to tell when to light the led in the right spot every time?
a timing circut linked to the compass?
Jul 18, 2005, 11:24 AM
Micro Flyer, Big Poster
Pete P's Avatar
Awesome!!! Post some plans and such!
Jul 18, 2005, 11:42 AM

Compass Info?


Great project. Can you tell us more about the PIC, what that is, and how you set up a heading with the compass? Any links would be great, and thanks in advance!

Jul 18, 2005, 12:51 PM
Registered User
unsped's Avatar
another person salivating for more info
Jul 18, 2005, 01:07 PM
B A bay B E be B I bicky bi
micro_builder's Avatar
amazing work. i just read through your MicroHeli 4 project, and the amount of work that must've been involved is staggering. simply fantastic

Jul 18, 2005, 03:31 PM
Registered User
Check your PM, please!
Jul 18, 2005, 05:31 PM
Frame Design Engineer
superdave42's Avatar
I'll buy one if ya mod one up for me :-)
Jul 18, 2005, 05:37 PM
Thanks for the Fish!
aerogel's Avatar
electronic compass Thingy is Brilliant
Jul 18, 2005, 05:45 PM
Registered User
Thread OP
Thanks for your interest

Here there is a better explanation:

The yaw stick, control where the heli is pointing. As all the body is rotating we use a LED that blinks in the same point of the revolution as an orientation point (imagine this as the tail of an heli) so when you see the blue LED you know where is the tail. (you can see this on the last photo of the first post).
If you move the yaw stick the LED rotates to the left or to the right as an heli tail does. I call this a "virtual yaw" o "virtual tail". Also because we have an electronic compass this tail works as if we have an heading-hold gyro because if we dont touch the yaw stick, the virtual tail is always pointing in the same direction.

With the Roll and Pitch stick is a bit more complex. With Roll and Pitch we calculate at what point of the revolution with respect to the virtual yaw (LED) we have to move the actuator to achieve the correct movement of the body (we have also to take acount of the gyroscopic precesion).

Here is a simple drawing of this...

I am planning to post videos tomorrow ( I hope)

Jul 18, 2005, 05:50 PM
Frame Design Engineer
superdave42's Avatar
that is sooo cool.
Jul 18, 2005, 06:31 PM
My member is not
Zlatko's Avatar

That is sooo good .

I tried to make a 4 rotor microheli like your first atempt, inspired by your work, but I used 3 gyros, 4 ESCs and 3 V-Tail mixers. I didn't have much luck with that method. The mixers would just "oscilate" by themselves ( I had two cascades ) . I tried a different brand of mixers, but not much luck. I used normal gyros, not HH gyros.

I would like to try the Vectron mod, this looks less complicated.

Will you be shearing the schematics and the code?


BTW I've ordered the X-UFO "thing" but still waiting for delivery .

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