aircraft. V-Tails are very popular in Europe, especially for gliders. In the US, the T-Tail is more common. V-Tails have the advantage of being lighter and creating less drag. They also are less likely to break at landing or take-off due to the tail striking something on the ground like an ant mound or a rock. Powerplants Most planes need a powerplant to drive them, the exception being gliders. The most popular types for radio-controlled aircraft are internal combustion engines, electric motors, jet engines, and rocket engines. Three types of internal combustion engines are available being small 2 and 4 stroke engines. Glowplug engines use methanol and oil as fuel, compressive ignition ('diesel') burn paraffin with ether as an ignition agent. Larger engines can be glowplug but increasingly common gasoline is the fuel of choice. These engines are spark ignited. In recent years electric powered models have increased in popularity due to the reducing cost and weight of components and improvements in technology, especially lithium polymer (LiPo) batteries and the choice of brushed motors and brushless motors. Electric systems are quieter and as they do not require fuel/exhaust, are cleaner. The advantage of electric power is the ease of starting the motor as compared to the starting of engines; electric motors that are comparable to engines are cheaper. Any form of lithium-chemistry battery cell technology packs have to be charged with "smart" chargers that have connections to every electrical connection in the pack to "balance-charge" the cells in the pack, and even with proper use of such chargers lithium-polymer battery packs can have the serious risk of fire or explosion, which has led to the increasing acceptance of cobalt-free, lithium iron phosphate battery technology in their place as a much more rugged and durable lithium-chemistry power source. Transmitting and Receiving Frequencies Frequency A transmitter and receiver of a radio control aircraft must both be on the same frequency so the aircraft can be controlled in flight. Traditionally, this transmitting and receiving frequency were referred to as a channel (technically, a frequency channel). This is not the same as number of servo channels that a plane can have, but can be confusing, as both are casually referred to as channels. It is less common now for radio control pilots to refer to frequency channels, as modern computer receivers in the gigahertz band are equipped with synthesiser technology and are 'locked' to