A post on RCGroups got updated last night. A new variable pitch multi-rotor craft got posted, and it looks very slick. This got me motivated again in continuing my work in this field.
While looking for the heli parts that were used in the above post, I came across this RC helicopter manuals collection of helis I never heard before. It’s good to know about it and see how other helis are designed and put together, for future ideas.
TREX 450 bible
HobbyHobby (Mississauga location)
Hobby-USA (carries CopterX Black Angel parts)
Value Hobby (in USA)
Airy Harden Blade II : Highly cambered blades that come in 238mm, 210mm, 185mm and 160mm.
The HoneyBee CP2 (that uses the 238mm blades) has a rotor speed of 17oorpm. So keep things under 2000prm. (Reference)
Supposedly, more surface area and more camber on these smaller blades for a Blade CX2/Lama V4.
Heli-Direct Pinions selection: well organized
In order to calculate your RC helicopter head speed, there are 4 things you need to know:
- The number of Teeth (T) of your motor pinion. If you set up your RC helicopter yourself, you should know that by heart. If you bought the RC Helicopter RTF (ready to fly) or someone set it up for you, just count the teeth of your motor pinion. It is a lot easier than counting the teeth of your main gear.
- The number of T of the main gear. This is easy to find – just count the teeth on your main gear. Well, not that easy – just try it, you’ll know what I mean. I get a different number every time I count it. Again, you may find the number of your main gear T on the owner manual.
- Motor kv - the rpm (head Speed) produced by a motor per volt applied. You should be able to get the motor kv from the motor specification sheet.
- Voltage: This is the voltage of your battery. You may get this information from your battery specification sheet or label.
- Efficiency rate: This is the percentage of your RC helicopter motor efficiency when you are flying with your set up. It is the norm to use 80% (.8) or 90% (.9) depending many factors though you run 100% on your throttle curve.
As it was said earlier, the result would only give you a rough estimate of the head speed. A better way is to use a tachometer to measure your RC Helicopter head speed.
Estimate Head Speed = (Motor kv * Battery Voltage /(Main Gear /Teeth of Pinion)) * Efficiency Rate
Going to put together a list of what I would need to build a quad rotor that can do some lifting. Quad built using motors on each corner.
Inspired by the stability of this quad. Video showing AP stability shown here.
LED Strips from HK to light the 4 corners.
Motors (listed in this post) Turnigy 2209. Going with this 20L-22 motor
Turnigy 18A speed controller from HK.
3.5mm plugs from HK
HK450 heli tail booms. Carbon Fiber ones, and Aluminum ones.
Props. Get them here?
Some more details.
I’ve decided to use William’s tricopter controller boards for my own copter.
Reasons being that I’m using 3 rotors, and that the code is written in basic, so that will be easy for me to edit.
I don’t plan on starting with the full IMU cube. Just 2 gyros will do for a start, and I will add on later. Probably a bad idea not to use the whole cube… should just bite the bullet, and make my life simpler, since the development of this copter is secondary to the platform I am after.
Also Will’s code will not dirrectly work on my machine, since I will be adjusting the pitch on the 3 corners, not the motor speed. And the servo that he controlls, will be used by me to control the main motor speed.
These modifications will be made to the code when I get to that stage.