Defence

Proposed subscale demonstrator with folding wing and articulated airframe could lead way to heavylift rotorcraft

Supported by US Army research funding, Baldwin Technology (BTC) has refined the design of its Mono Tiltrotor (MTR) cargo rotorcraft. It combines a coaxial proprotor with a folding wing, articulating airframe and cargo-container handling system.

The Port Washington, New York-based firm is designing a proposed subscale demonstrator, the MTR-SD, that could be folded and stowed inside a shipping container as well as prove the design for a larger heavylift rotorcraft.

Working with Eagle Aviation Technologies and the University of Maryland, BTC has selected two Honeywell/Rolls-Royce T800s to power the 4,260kg (9,400lb) gross-weight MTR-SD. The engines are slung under the four-blade coaxial-rotor drive system. The payload is suspended from the gearbox on telescoping struts.

The MTR takes off and lands like a helicopter, but as forward speed increases the folded wing deploys aerodynamically, locks in place and the rotor tilts forward to become a contra-rotating propeller.

There is a single tailboom with T tail, replacing a pivoting twin-boom tail pinned parallel to the suspension structure in the hover. The tailboom is now free of the payload, and the empennage outside the rotor downwash, during hover.

In low-speed forward flight, the tail is extended like a conventional helicopter and the folded wing panels hang below the boom. At wing deployment speed, the tailboom is lowered to give the wing panels a positive angle of attack.