Homebuilt airplanes are also known as “kit” planes or “experimental planes”. They are not casual things to build and their construction should not be taken lightly, especially if you plan on actually going up in the air. We are going to talk circuit breakers and panels. So if you need a non airplane expert, call 110220v.com!
There are many different aspects of building a homebuilt. One of the most critical aspects is the electrical system. You might think the most critical part is the engine, but if the engine fails in an airplane a skillful pilot can glide the aircraft to the ground in the correct conditions. However if the electricity in an airplane fails, the pilot will lose all control of the aircraft and a fatal crash is much more likely.
Lets take a look at some of the electrical components of planes that need to be done right.
The Control Panel
The pilot’s control panel is the most critical part of the plane to the pilot. This is where all the decisions, adjustments, and piloting actually takes place. The usability of the control panel in flight is of critical importance. Of similar importance is the ability to work on, install, and maintain the control panel. Some kit makers recommend that you build your panel with a skeleton base and panels fastened in the front with rivnuts and screws. This makes it easy to loosen and work on the panel’s insides by simply unscrewing from the pilot’s seat. To do this make sure you make your wiring long enough to be pulled up to this point and even “out” into the pilots compartment, when you are working on them.
Since you are building your own plane, the exact panels that you include are up to you somewhat. But if you are planning on flying your plane, you’ll want to have strict standards on which ones you are including. Well known kit builders recommend:
- flight instruments
- engine instruments
- electrical switches and magneto switch
- radio equipment
- non-avionic circuit breakers
The Circuit Breakers
Next let’s look into airplane circuit breakers.
(BTW, more information can be found here )
Circuit breakers purpose is to stop the power from overflowing and overeating a circuit, causing it to short. But believe it or not circuit breakers act as an “on/off” switch in some airplanes and circumstances. For example in emergency landing gear extension procedures, the pilot is often taught to pull the gear operating breaker so that bad signals won’t be sent to the gear during the emergency. Much like “resetting” a computer by turning it off and on, pilots often relied upon “resetting” a particular circuit that was acting wonky by breaking it temporarily.
But in recent times the FAA has veered away from promoting that as a viable practice. Many new airplane designs are putting the breakers out of reach of the pilots because they see it as a potential for errors and overuse.
They are also moving circuit breakers outside of the pilot’s purview because it allows more wires to be included in the panel space. But we are not experts on whether you should include the circuit breakers in the panels.
Another reason for moving them out of the cockpit is that after a certain amount of “popped” breakers, the breaker becomes reliable. So it’s important to be very vigilant about over usage of circuit breaker popping.
Finally, make sure your switches, volt and amp meter, & circuit breakers, are all manually tested and observed personally. Also, you can always call an expert electrician like 110220v.com
Wiring on a kit built airplane is one of the biggest risks of building the plane. It’s common to find homebuilt planes to have defective wiring. The homebuilt industry doesn’t have big players
The key components of the wiring infrastructure are the avionics, intercoms, and electric components.
Make sure you commit your wiring plan to paper. Don’t try to do it in your head. For God’s sake create a wiring diagram that has the parts and components ratings.
Many kit experts recommend that you have a two busses. A main electrical bus and a avionics/radio bus. This is important so if necessary you can shut down one without the other. This comes in very handy during engine start up sometimes.
Make sure you have a switch for your alternator field, so you can turn it off and on to maintain control. With this setup your voltmeter can alert you to whether your voltage regulator is working. This will help prevent your from damaging your costly components, like radios, if you move to battery power quickly and turn off the alternator field.
Finally make sure that when you are doing your wiring you are looking at the big picture. Wiring takes into account every part of the electrical components of your kit. Map all your components out on a piece of paper and look at how the wiring will connect to them all. Take into account the future maintenance you will be doing and whether you can reach everything needed.
Finally, here is a GREAT video about this exact topic!