A Hucks starter is an auxiliary power unit, almost always a motortruck, that provides initial power to start up piston

Reciprocating engine

A reciprocating engine, also often known as a piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion. This article describes the common features of all types...

 aircraft engine

Aircraft engine

An aircraft engine is the component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines...

s. Such Hucks starter trucks can be considered a mechanical replacement for a member of the groundcrew

Groundcrew

In aviation, the groundcrew is the support crew supplying the aircraft with fuel and maintenance, as opposed to the aircrew.In airlines, ground crew members include:*Airframe and powerplant technicians*Avionics technicians*Baggage handlers*Rampers...

 who would have spun an aircraft

Aircraft

An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

's propeller

Propeller (aircraft)

Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...

 by hand. This is because of the starter truck's position in front of the airplane when starting, much like a groundcrew member.

Operation

The power is transmitted to the aircraft via a power take-off

Power take-off

A power take-off or power takeoff is a splined driveshaft, usually on a tractor or truck, that can be used to provide power to an attachment or separate machine. It is designed to be easily connected and disconnected...

 shaft, much like those found on the drive trains of rear-wheel drive vehicles, or agricultural machines. The shaft of the starter fits into a special protruding hub incorporating a simple projecting claw clutch

Freewheel

thumb|Freewheel mechanismIn mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft...

 on the center of the airplane's propeller assembly. When engaged, the power of the truck's engine is transmitted to the aircraft engine until start up, whereupon the faster speed of the now-running engine disengages the clutch, and then the starter truck clears the area prior to take-off.

The device was named after its inventor Bentfield Hucks, who was a captain in the Royal Flying Corps

Royal Flying Corps

The Royal Flying Corps was the over-land air arm of the British military during most of the First World War. During the early part of the war, the RFC's responsibilities were centred on support of the British Army, via artillery co-operation and photographic reconnaissance...

at the time.