The tilt-rotor Bell Boeing V-22 Osprey program received a boost last week when the U.S. Marine Corps took delivery of the latest variant. The Osprey, which began development some 30 years ago, combines the helicopter's ability to take off and land vertically, with the speed of a regular aircraft. The recently delivered Block C variant includes an improved weather radar system, an upgraded crew and passenger aircon system, improvements to the cockpit Electronic Flight Instrument displays and upgrades to the Electronic Warfare Systems that allow the aircraft to better defend itself from sea, ground and airborne attacks.

The Osprey looks like a twin-engined fixed wing aircraft with a pair of over-sized props mounted on the ends of a stubby wing. Unlike the famous Harrier jump-jet, the Osprey gets its VTOL capabilities by tilting its two engines backwards so that they are aimed vertically, providing lift rather than horizontal thrust. Once underway, with the engines facing forward, it has greater efficiency and almost twice the speed of a helicopter as it is able to rely in its wings for lift, therefore not suffering from the retreating blade stall issues of a rotary wing aircraft when it tries to go fast.

V-22 Osprey at the Dubai Airshow (Photo: Bell Boeing)

If an engine fails, the aircraft has cross shafting that physically transmits shared power to both rotors from the remaining engine to allow a safe landing and recovery and its system redundancy is boosted by features such as triple-redundant fly-by-wire flight control systems.

The Osprey's unique characteristics offer distinct tactical and logistical advantages for the military, but the technology has much to offer in a civilian version, something that has been keeping the AgustaWestland engineers busy developing the AW609.

Civilian version of the tilt-rotor concept - AgustaWestland AW609

Although a pretty simple concept - having been proposed almost 82 years ago - a number of attempts made over the years without commercial success. Given the complexity it is not surprising that Boeing's tiltrotor program has had its share of setbacks, but the Osprey seems to have proven the proponents right. There are now more than 160 units flying worldwide and having amassed an impressive 130,000 flight hours, reliability is second to none amongst the Marine Corps helicopter fleet ... plus it's one of the cheapest to operate.

Cockpit upgrades include new weather radar system and improvements to Electronic Flight Instrument displays (Photo: Jamie Darcy of NAVAIR)

Key features of the Bell/Boeing V-22 Osprey

Designed for NBC (Nuclear, Biological and Chemical) environments

Full NVG (Night Vision) compatible cockpit

Fully shipboard compatible electronics (this is harder to do than with land based aircraft as there's lots of high power RF around the boats)

Fully marinized (i.e. material and coatings thwart corrosion)

Electrical de-icing capability on leading edges and rotors

Quieter than a turboprop in flight

Folding wing and blades enable stowage below deck of an aircraft carrier

Aircraft range allows over-the-horizon placement of naval assets out of harms ways and expands littoral warfare capability of the fleet

First "all composite structure" military aircraft

Source: Boeing