While the U.S. Navy is moving to larger unmanned rotorcraft with greater payload capacity and endurance, European navies, with their smaller ships, are still deciding what size aircraft will best meet their needs. So far, European manufacturers have led in developing small vertical-takeoff-and-landing (VTOL) unmanned aircraft systems (UAS), but larger vehicles based on existing light helicopter designs are emerging.

•Tanan: EADS-Cassidian's 300-kg (660-lb.) UAS rotorcraft for navy/army features a heavy-fuel engine for mil-spec kerosene fuels. Flight trials are underway and Cassidian plans sea trials with EADS-Astrium's DeckFinder automatic VTOL system next year.

•Pelicano: Spain's Indra begins deliveries of its 200-kg Pelicano tactical UAS helo this year with a naval variant capable of auto-VTOL in rough seas available in 2013. Co-financed with Spain's ministry of industry and based on the Swedish CybAero APID 60 UAV rotorcraft, it offers 6-hr. endurance, 100 kph average speed and up to 12,000-ft. altitude from BAM patrol boats or F80- and F100-class frigates. Naval mods to APID 60 include heavy-fuel engine, airframe reinforcing, corrosion protection and main-rotor redesign for autorotation capability.

•Camcopter S-100: The most established small VTOL UAS in Europe built by Austria's Schiebel. With a heavy-fuel engine, the 200-kg rotorcraft is in service with the United Arab Emirates army and has been tested by the Australian, French, German, Pakistani and Italian navies.

•Skeldar: Saab's 200-kg V-200 rotary-wing UAV offers maritime variant with 150-km range. Shipborne trials with French and Swedish navies are underway. It boasts “high autonomy” during take off and landing.

•Neo S-300: The 100-kg Swiss UAV rotorcraft tested DeckFinder in arctic conditions last fall in the Baltic Sea onboard the German federal police ship Bredstedt.

•SW-4 Solo: AgustaWestland has completed a prototype of UAS and optionally piloted helicopter based on a 1,600-kg light single-turbine helicopter built by Polish subsidiary PZL-Swidnik. Manned flights begin this year with unmanned flights slated for 2013.

MQ-8B Fire Scout: The U.S. Navy's Northrop Grumman VTOL tactical UAS weighs in at 1,430 kg, but a larger MQ-8C—based on the 2,700-kg Bell 407 light helicopter—is in development to provide increased payload capacity and endurance for naval special forces.