MARIGNANE, France (Reuters) - Airbus Helicopters showcased an experimental half-plane, half-helicopter on Wednesday in a quest for speed as competition heats up to define the rotorcraft of the future.

The Racer is a one-off demonstrator model that combines traditional overheard rotor blades with two forward-facing propellors in a bid to combine stability and speed, shortening response times for critical missions like search-and-rescue.

"There are missions where the quickest possible access to the zone is vital. We often talk about the 'golden hour'," Airbus Helicopters CEO Bruno Even told Reuters, referring to the window considered most critical when people need urgent medical attention.

Airbus Helicopters was due to fly the aircraft at its Marignane base outside Marseille in front of 150 industry officials, politicians and representatives from the European Union, which gave support through its Clean Sky 2 initiative.

The demonstration comes months after Italy's Leonardo and U.S. manufacturer Bell agreed to co-operate on enhancing existing tilt-rotor technology.