Takeoff is the phase of flight in which an aerospace vehicle goes from the ground to flying in the air.
For aircraft that take off horizontally, this usually involves starting with a transition from moving along the ground on a runway. For balloons,helicopters and some specialized fixed-wing aircraft (VTOL aircraft such as the Harrier), no runway is needed. Takeoff is the opposite of Landing.
Landing is the last part of a flight, where a flying aircraft or spacecraft (or animals) returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called “landing” and “touchdown” as well. A normal aircraft flight would include several parts of flight including taxi, takeoff, climb, cruise, descent and landing.
The Different Types of Takeoff & Landing
1.Horizontal Takeoff & Landing
HOTOL, for Horizontal Take-Off and Landing, was a British design for an Airbreathing jet engine spaceplane by Rolls-Royce and British Aerospace.
Designed as a single-stage-to-orbit (SSTO) reusable winged launch vehicle, it was to be fitted with a unique air-breathing engine, the RB545 or Swallow, to be developed by the Rolls-Royce company. The engine was technically a liquid hydrogen/liquid oxygen design, but dramatically reduced the amount of oxidizer needed to be carried on board by utilising atmospheric oxygen as the spacecraft climbed through the lower atmosphere.
Since propellant typically represents the majority of the takeoff weight of a rocket, HOTOL was to be considerably smaller than normal pure-rocket designs, roughly the size of a medium-haul airliner such as the McDonnell Douglas DC-9/MD-80. Ultimately, comparison with a rocket vehicle using similar construction techniques failed to show much advantage, and funding for the vehicle ceased.
CTOL is an acronym for conventional take-off and landing,and is the process whereby conventional aircraft (such as passenger aircraft) take off and land, involving the use of runways.
STOL is an acronym for short take-off and landing, aircraft with very short runway requirements.
RTOL is an acronym for Reduced take-off and landing.
CATOBAR (Catapult Assisted Take-Off But Arrested Recovery or Catapult Assisted Take-Off Barrier Arrested Recovery) is a system used for the launch and recovery of aircraft from the deck of an aircraft carrier. Under this technique, aircraft launch using a catapult-assisted take-off and land on the ship (the recovery phase) using arrestor wires.
STOBAR (Short Take-Off But Arrested Recovery) is a system used for the launch and recovery of aircraft from the deck of an aircraft carrier, combining elements of both short take-off and vertical landing (STOVL) with catapult-assisted take-off but with arrested recovery (CATOBAR).
2.Vertical Take-Off and Landing
VTOL is an acronym for vertical take-off and landing aircraft. This classification includes fixed-wing aircraft that can hover, take off and land vertically as well as helicopters and other aircraft with powered rotors, such as tiltrotors.The terminology for spacecraft and rockets is VTVL(vertical takeoff with vertical landing).Some VTOL aircraft can operate in other modes as well, such as CTOL (conventional take-off and landing),STOL (short take-off and landing), and/or STOVL (short take-off and vertical landing). Others, such as some helicopters, can only operate by VTOL, due to the aircraft lacking landing gear that can handle horizontal motion. VTOL is a subset of V/STOL (vertical and/or short take-off and landing).
A short take-off and vertical landing aircraft (STOVL aircraft) is a fixed-wing aircraft that is able to take off from a short runway (or take off vertically if it does not have a heavy payload) and land vertically (i.e. with no runway).
VTOHL Vertical Take-Off and Horizontal Landing as well as several VTOHL aviation-specific subtypes: VTOCL,VTOSL, VTOBAR exist.
Launch and Recovery Cycle
Vertical takeoff, vertical landing (VTVL) is a form of takeoff and landing for rockets. Multiple VTVL craft have flown. As of 2012, at least six VTVL rocket vehicles are currently under development at four different aerospace companies. VTVL is often proposed as a viable technology for reusable rockets. VTVL rockets are not to be confused with aircraft, where that class of aircraft which takeoff and land vertically (helicopters, etc.) are known as VTOL aircraft.
Horizontal Takeoff , Horizontal Landing (HTHL) – is the mode of operation for the first private commercial spaceplane, the two-stage-to -space Scaled Composite Tier One from the Ansari X – Prize SpaceShipOne/WhiteKnightOne combination.
HTVL or horizontal takeoff and vertical landing is the spaceflight equivalent of aviation HTOVL (and its subtypes CTOVL, STOVL, CATOVL). This mode of operation has not been used, but has been proposed for some systems that use a two-stage to orbit launch system with a plane based first stage, and a capsule return vehicle.
SOURCE : WIKIPEDIA