Remote control airplanes have been used all around the world for years. However, it was not until 2000s that their usage has been widely increased, and it came naturally with improvements in technology. As the time passed by, cost, design and capabilities of remote control airplanes were developing quickly. Today, wide variety of models and styles is available, and everyone can find the one that will suit their needs. Remote control airplanes have found their place in scientific, government and military organizations as well. They are being used for various experiments, aerodynamic modeling, and military is often using them even as the spy planes, for gathering all kinds of important informations from the enemy. Also, not all of the rc airplanes are for usage. Some of them are maid purely for display and these kind of models are usually made of wood. As for the others, depending on their purpose, remote control airplanes can use different power sources.
Those models that are made for hobbyists, as well as those for professionals, contain a mechanism powering propulsion of the aircraft. Most common propulsion systems are electric motor and IC (internal combustion engines).
In electric powered models, battery powered electric motor is used. One can achieve throttle control through an electronic speed control, which regulates the motor’s output.
At first, these kind of electric models were equipped with brushed DC motors, and they had an unflattering flight time of max 10 minutes. On the other hand, fully fueled glow-engine system of similar weight and power would likely be able to produce flight-time that’s twice that much.
Later on, with tech development, electric systems used even more efficient brushless DC motors, and this resulted in improved flight time. Brushless type of motors are also known as outrunner motors for airplanes.
It works by spinning its outer shell around its windings similar as motor in your CD-ROM. What’s more interesting, you can convert CD-ROM motors to aircraft use.
Maybe the bad side is that outrunners spin slower than inrunner motors, with their more traditional layout, while they are producing far more torque. But exactly this is what makes an outrunner type of motor an excellent choice for directly driving electric aircrafts, because they are able to eliminate the extra weight and complexity of a gearbox. Outrunner motors have quickly become popular and are now available in many sizes. Their compact size and high efficiency make them widely popular in other types of models too.
Most of hobby people refer to the word gas airplanes, but mostly the airplanes are powered by a nitro engine (also known as a glow engine) and usually bigger scale models have real gas engines.
The only differences between the engines are following:
- Nitro engine use glow fuel (a mixture of methanol, nitromethane, and oil.) while gasoline engines use a mixture of regular gas and oil,
- Nitro engines use glow plugs to ignite the fuel, but gasoline engines use spark plugs. Glow plugs produces a red hot spring when a voltage of 1.5V is applied, but spark plug produces a spark when needed, operating voltage from 10’000-20’000 volts, yes that’s not a typo thousands of volts. Real car engines produce up to 30’000 volts for spark plugs.
Types of construction
As with other radio controlled models, you can get Ready To Fly RC plane kits or you can assemble one by yourself.
Ready To Fly
Ready To Fly airplane kits usually come pre-assembled and everything you are required to do is to attach one wing, or some kind of similar easy to do job.
Everything is already included in the kit. This means that with model, you get a transmitter, receiver and a battery. The bad side of these is that you also get configuration of the models pre-determinated.
Almost Ready To Fly
These types of airplanes need a motor, transmitter, receiver and battery to be completed. All in all you receive only the model itself and you’re required to purchase the main electronics yourself.
DIY remote control airplanes
On the other hand, you can always build planes from previously published plans, with included instructions. Usually, parts need to be cut out from sheet wood using templates. A model plane built from scratch is more valuable than “industrial” one, because you created the project from the plans. The latest and more specialized designs are usually not available in a kit form. This is something that professionals often do, because this way they can suit the rc airplane to their needs completely.
Another important factor after selecting the engine or electric motor is the propeller selection.
You must always remember that internal combustion engine propellers go on a IC engine and electric motor propellers go on an electric motor. You can put a gas engine propeller on an electric motor, but never put an electric propeller on a gas engine.
Propellers come in many different seizes and shapes. The size of the prop is given in 2 numbers (6×3, 10×6). The first number is the diameter of the prop in inches. The second number is the pitch or twist of the propeller. The larger the number, the greater the pitch. A propeller with a pitch of 4 will move forward 4 inches when rotated one revolution.
Check the image below for a comparison look between an electric propeller and a gas propeller. The electric propeller is on top and the gas one is on the bottom. The main difference is the thickness around the hub where the electric one is a lot narrower than the gas one.
When it comes to selecting propellers I would recommend APC Propellers because they are very well known around the world and their props are efficient, which means you’ll get more run time out of your model with the same thrust compared to other propeller brands.