Aerial refueling is a procedure that basically allows the receiving aircraft to remain airborne longer, extending its range or loiter time on station. A series of air refuelings can give range limited only by crew fatigue and engineering factors such as engine oil consumption. Potential fuel savings in the range of 35-40% have been estimated for long haul flights. The two main refueling systems are probe-and-drogue, which is simpler to adapt to existing aircraft, and the flying boom, which offers faster fuel transfer, but requires a dedicated operator station. Continue reading for more.
5. Specialized Aircraft
Usually, the aircraft providing the fuel is specially designed for the task, although refueling pods can be fitted to existing aircraft designs if the "probe-and-drogue" system is to be used (see later). The cost of the refueling equipment on both tanker and receiver aircraft and the specialized aircraft handling of the aircraft to be refueled (very close "line astern" formation flying) has resulted in the activity only being used in military operations.
4. No Civilian Model
There is no known regular civilian in-flight refueling activity. Originally employed shortly before World War Two on a very limited scale to extend the range of British civilian transatlantic flying boats, and then after World War Two on a large scale to extend the range of strategic bombers, aerial refueling since the Vietnam War has been extensively used in large-scale military operations for many different military aircraft operations.
3. Boom System
US Air Force fixed-wing aircraft use the flying boom system. Typically countries operating F-16 or F-15 variants have had a need for boom equipped tankers. Therefore, in addition to the USAF, the boom system is used by the Netherlands (KDC-10), Israel (modified Boeing 707), Turkey (surplus US KC-135Rs), and Iran (Boeing 747). New tankers are under development, see KC-X.
2. Longest Manned Flight Record
A mission modified Cessna 172 Skyhawk with a crew of two set the world record for continuous manned flight without landing of 64 days, 22 hours, 19 minutes, and five seconds in 1958 by refueling and transferring food and supplies from a convertible top Ford Thunderbird automobile. The publicity flight for a Las Vegas area hotel ended when the aircraft's performance had degraded to the point where the Cessna had difficulty climbing away from the refueling car.
Helicopter In-Flight Refueling (HIFR) is a variation of aerial refueling when a naval helicopter approaches a warship (not necessarily suited for landing operations) and receives fuel through the cabin while hovering. Alternatively, some helicopters equipped with a probe extending out the front can be refueled from a drogue-equipped tanker aircraft in a similar manner to fixed-wing aircraft by matching a high forward speed for a helicopter to a slow speed for the fixed-wing tanker.