UPDATE 01Feb2010: Kinda thinking I should spend my money on a Arduino controlled copter, mainly since that’s the direction I will be heading into in the future anyway, and this way I can totally reuse all the components in the future.

Cost breakdown for a tricopter from this thread:

Item	Amount	Single [Euro]	Total [Euro]
Arduino Pro mini (m328p, 5V 16 MHz)	1	16	16
Accelerometer Breakout Board ADXL322	1	25	25
Gyro Breakout Board ADXRS610	3	54	162
TriGUIDE PCB (DIY)	1	11	11
Motors FC28-22	3	4	12
ESC (I²C)	3	40	120
…or standard ESCs in combination with my I²C->PWM converters
Props EPP0845	2	3.2	6.4
Servo Bluebird BMS371	1	6.1	6.1
USB -> serial converter	1	12	12
Rec-Enc (recommended)	1	30	30
Frame	1	?	?
Lipo battery 3S 2200 mAh	1	?	?
		TOTAL:	400.5

This uses a Arduino CPU. The asselerometers and gyros are the expensive bits. Look for cheaper alternatives.

The Rec-Enc I can’t find. Look at this thread for a PPM converter. They use this converter priced at reasonable $25.

Read this for CCPM mixing on the Futaba 6ax

Tricopter build. Uses only a heli radio, and gyros. No control board. This is the one to try and build, since it’s simple. I can use the arduino board to do the CCPM mixing which the Tx would normally do.

Updated Cost breakdown:

DT 750 motor X3 http://hobbycity.com/hobbycity/store…utrunner_750kv
$10.95 total $32.85

The review on Hobbycity.com rated this motor at putting out 40oz thrust. 3 of these would put out 120oz or 3.4kg pf thrust. That’s HUGE! Should be more then enough for me.

You can use any motor in the 600-1000kv range. The lower the Kv, the more resolution each step of the speed control will give you. Motors over 1000 Kv are more difficult to make stable. That said, some have used ducted fans and made it work.

Speed controls X3
http://hobbycity.com/hobbycity/store…d_programmable)
$9.23 total $27.96
BEC X1
http://hobbycity.com/hobbycity/store…oise_Reduction
$7.83

speed control programmer X1
http://hobbycity.com/hobbycity/store…ogramming_Card
$6.95  This just makes things easy, its worth $7

Battery X? this battery works great.
http://hobbycity.com/hobbycity/store…00mAh_3S1P_20C
$10.99

3.5mm connectors X2
http://hobbycity.com/hobbycity/store…idproduct=4136
$4 Total $8

Gyro X3
http://hobbycity.com/hobbycity/store…Digital/Analog)
$24.79 total $74.37

Yaw gyro X1
http://hobbycity.com/hobbycity/store…zo_Gyro/Futaba
$23.95

Better and cheaper yaw gyro is the EK2-0704 from ebay. only $12!

Volt warning A must have!!!!
http://hobbycity.com/hobbycity/store…ery_Monitor_3S
$4

This is $185, you still need wire, battery plugs, a servo.

——————

May have just made the build a little cheaper. Only 2 gyros required, and one headying (yaw) gyro. Need a couple of V-Tail mixers which are dirt cheap at $2.95.
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6321

See diagram here: http://www.rcgroups.com/forums/attachment.php?attachmentid=2934020

This would bring the total down to $160 (plus materials to build the frame, say $30 in wood at the hobby store)

To do CCPM mixing, I could use one of these. It will eliminate the yaw gyro, so the price is right.

http://www.amainhobbies.com/product_info.php/products_id/27017/n/Ace-R-C-Heading-Lock-Gyro-w-E-CCPM-Mixer-TG6100M