Nord 1700 Norélic
| Company type | Prototype helicopter |
|---|---|
| Industry | Aerospace |
| Founded | 1947 |
| Headquarters | France |
| Products | Helicopters |
The Nord 1700 Norélic, also known as the SNCAN N.1700 Norélic, was a French helicopter prototype distinguished by its pioneering control mechanisms. Only a single example was constructed, intended to serve as a foundation for subsequent production models.
Design and development
The Norélic was designed as a two-seat helicopter with a single main rotor, notable for its distinctive anti-torque configuration and the elimination of manual cyclic pitch input. The crew sat side-by-side beneath expansive front windows, while the cockpit sides remained open. It was powered by a vertically mounted Mathis G.7R seven-cylinder radial engine—a pioneering installation in French helicopter design—which transmitted power through a driveshaft ascending through the fuselage to an offset rotor hub supported by two streamlined pillars.
Its rotor system comprised two fully articulated blades with flapping hinges and consistent chord length, built around a solid spar sheathed in metal. Blade pitch adjustments were automated through small servo airfoils positioned perpendicular to the main blades; these flappable servos handled both cyclic pitch variations and flapping motions, thereby removing the necessity for conventional cyclic controls within the cockpit. Lateral control was achieved by shifting the rotor hub sideways to separate lift from gravity centers, while fore-and-aft hub movements compensated for center-of-gravity imbalances. Additionally, these servo blades functioned as rotor speed governors by increasing blade pitch and drag in response to rising rotor RPM. Collective pitch was primarily governed by throttle settings but included a manual override lever.
The fuselage tapered conically behind the engine, culminating in an innovative anti-torque system patented by André Bruel: an axially driven pusher propeller encased within a circular duct forced airflow through four rotatable vertical airfoils mounted along the shroud’s trailing edge. This system automatically counterbalanced rotor torque through hydraulic torque sensor feedback and managed yaw control while simultaneously providing forward propulsion. The duct shielded the propeller from rotor downwash, ground obstacles, and personnel hazards. Pitch control was executed via two horizontal surfaces affixed to the shroud. The landing gear featured cantilevered mainwheel legs and a tailheel integrated into the propeller shroud.
The Norélic’s maiden flight occurred on 17 November 1947, followed by testing that extended into 1949. Although its control systems demonstrated effectiveness, two accidents caused damage that ended further development efforts. Proposed production variants with improved cockpit glazing and streamlined rotor components were never realized. Subsequently, Bruel developed the smaller, lighter single-seat Nord 1710, which incorporated similar control principles along with additional horizontal surfaces inside the duct for pitch regulation; it first flew in July 1950 but was discontinued after accidents within its first year of operation.