Propellers

Without them you couldn’t get off the ground and without knowing which one to use for your particular application you wouldn’t be any better off.  Props come in many shapes and sizes.  They are also made from many different materials such as abs plastic, wood, and carbon fiber.

_WDG9833

 

Finding out which is right for your application is very important and there are a few simple ways you can make that determination.  The first thing to check are the specifications of your motors.  The documentation for most motors will generally come with recommended propeller sizes as well as thrust and amperage draw measurements for each different size propeller they recommend.  Propellers come marked from the manufacturer using a standardized sizing system.

_WDG9837

 

You will notice on the propeller above it names the manufacturer and also the number 10×4.7.  The first number will always be the length of your propeller in inches.  The second number signifies that this propeller in a perfect world would give you 4.7 inches of forward travel for every rotation.  Typically a number of 4.7 or below is known as a “slow fly” propeller and is generaly used with motors which have a lower kv rating and more torque.  Propellers with a pitch larger than 4.7 are typically for faster higher kv motors which have less torque.

Multi-rotor aircraft add another layer of complexity to propellers in that they use both clock wise rotating and counter clockwise rotating propellers.  In the case of a quad copter they have two of both.  This is a necessity to maintaining stable flight and attitude.  On a quad copter the torque of the clock wise rotating and the counter clockwise rotating motors acts to cancel out any tendency the aircraft might have to spin either left or right though no control input had been given.  This allows the quad copter to achieve yaw movement by alternating the opposing motors RPM.  Propellers are usually designated with a CW or CCW marking.

Much more information on propellers and motors can be found online.  In the resource section of the blog you can find some great places to look.

Resources

For any person who might be interested in creating a multi-rotor for themselves I have compiled a collection of vendors where you can find everything that you will need.  Prices will generally be reasonable but shipping might take longer than most are accustomed to.  This is due to the fact that most of these vendors are out of China.  China, for some time now, has been a leader in the multi-rotor industry providing low cost and surprisingly high quality components.  Below are a list of vendors all of which have been reliable and I use on a regular basis.

Other very helpful sites for information include:

There are many more resources out there but these have been some of the most helpful to me.  Shop around and do some reading.  You will be surprised how easy you can pick this up with a little research.

 

Safety

Another incredibly important aspect of this methodology is safety.  There are many different components of this system that are inherently dangerous and as such, proper care should always be exercised when operating any multi-rotor aircraft.

There are several things that you can do that will help ensure that you will almost always have a safe and uneventful flight.  One of the first things you can do is make sure that all of your batteries are properly charged and not damaged.  This includes the battery in your transmitter.  If a battery is physically damaged or won’t accept a full charge the battery should not be used and it should be disposed of properly.  Much like with larger aircraft, it is also always advisable to do a preflight check.  Inspect the multi-rotor for loose connections and any physical damage.  Always ensure that all propellers are sufficiently tight and that they are free from imperfections.  Never use a chipped or cracked propeller.  The brushless motors used by these systems spin at many thousands of revolutions per minute and a chipped propeller can quickly become a projectile.  Special care should also be taken to ensure that hands and fingers are not within striking distance of the propellers at anytime.  Whenever one approaches a multi-rotor they should also ensure that the Flight Control Unit is disarmed.

Spatial awareness is also very important.  Ensure that anyone around you remains a reasonable distance from where the multi-rotor is being operated.  A malfunction can always lead to unforeseen flight behavior.  Always be aware of your surroundings and constantly be aware of any obstacles that might hinder your flight.  It is also important to test any new systems in non populated areas and ground testing should be conducted as much as possible before flight.  Above all, always take your flights seriously and always fly in a responsible manner.