The Rivaero ‘uTe’ (so-named for its ‘utility’ capability) is an attempt to assimilate, enhance and develop best-practice gyroplane technology in order to introduce a safe, reliable utility gyroplane, designed specifically to be operated in the ‘Special Purposes Operations’ categories in accordance with SACAA TGM – Part 21.
The major inspiration during the R & D phase of the uTe design programme was ‘modularity’ – this design philosophy envisages fast, fuss-free conversion between many different roles in private, commercial, government-agency and quasi-military operations. Although very well-suited for recreational flying, the new Rivaero uTe has been specifically designed and built to be utilised in these Special Purposes Operations, or wherever else a rugged, work-horse gyroplane may be required.
Innovation is one of the key driving forces behind our design philosophy at Rivaero and the new uTe prototype is bursting with innovative ideas and features:
• Depending on the envisaged role, the uTe can be powered by either a purpose-designed aero-engine of European manufacture (UL350i) or, where the demands of ‘Special Purpose Operations’ require more powerful options, a FHI EJ 25 auto-engine conversion . . . a very successful, proven auto-to-aero conversion model!
• A generous, 30 ℓ touring baggage-carrying capacity, even when operating the aircraft in the dual configuration. The baggage carrying area features an innovative ‘soft-insert’ packing system!
• A bladder-type fuel containment system features fuel tanks which are completely ‘firewalled’ from the cockpit interior. The nitryl-rubber fuel bladders, designed to resist rupture, are fitted within two, separate compartments which are skinned with penetration-resistant lining. These features greatly reduce the chance of fuel fumes from a ruptured tank igniting and a fire spreading into the cockpit, following a survivable accident.
• Flight-control system-complexity and parts-count has been dramatically reduced by replacing the traditional control rod and bell-crank system with simple, sturdy push-pull cables.
• The wheel-rim/tyre combination is the same for all three wheels so that, should a main-wheel develop a problem during an away-from-base deployment, it could be easily switched with the good nose-wheel assembly, in the field, using generally available tools.
• Full trim control is provided in all three axes, pitch, roll and yaw.
• The aircraft electrical system is protected by electronic circuit breakers which can be electronically re-assigned with respect to rating and function. With ample spare capacity and freedom of choice, a minor electrical system error such as a faulty circuit breaker, need never again delay operations unduly while fault finding, repair and replacement spare parts are being waited on.
• During construction, each sub-assembly component is marked with a permanent, distinct, tamper-proof labelling-system, which is correlated with a logged build-file for each aircraft and stored in a permanent archive. Unauthorised modification or alteration thus becomes impossible to conceal.
Special Purpose Operations
In addition to the rear seat / dual flight-control system (the ‘standard’ configuration), the rear cockpit features a unique equipment changeover system.
This allows uncomplicated, rapid conversion between the various special purpose equipment systems, available as optional extras, according to customer requirements and specifications. The rear seat-mounting hardware is of a common design with the mounting-system affixed to the base of all the various, modular equipment-suites, designed to be accommodated in the rear-cockpit:
- Various data-capture equipment and mast-mount transmitter/receiver antenna options.
- A range-extending, 50 ℓ fuel-tank, which provides a 2 hour increase in endurance.
- A 100 ℓ utility-equipment crate which is designed for the ferry of light tools and equipment, but is equally capable of accommodating extra baggage, spare parts, fuel ‘jerry-cans,’ camping gear, etc.
- A 150 ℓ spray tank coupled with various, purpose-made aerial-baiting or ‘crop-splashing’ spray-boom arrays.
- Aerial-release machine options, capable of metered release of sterile insects (fruit-fly, boll-worm, moth and tsetse-fly species) as well as pelletized invader-species poison, etc.
- Airborne survey equipment (ground-penetrating ‘radar’) options.
Composite, aluminium frame sub-assembly
The uTe airframe consists of triple-redundant, resilient, lightweight, extruded-aluminium sub-assemblies constructed from tough, heavy-duty, corrosion-resistant 6261-T6 aluminium – these are bonded and bolted together, to form a robust, durable frame.
All bolts used in the primary structure of the aircraft are of the best-quality ‘AN’ (Army & Navy) specification hardware.
Benefits of such a design are:
• Safety – Welded steel frame-sections, utilised as the basic structure of many gyroplanes, tend to fail at the welds in a way which ‘hides’ propagating weld-failures from detection with the naked eye during routine inspections! To identify faults, weld-failures and cracks, frame sub-assemblies must be periodically disassembled, and submitted to expensive, laborious testing. Welds are also notorious rust-propagation areas, while 6261-T6 aluminium is rust-proof.
• Maintenance – Multi-member aluminium sub-assembly design means wear or damage can be easily detected during routine inspections & allows prompt replacement of only damaged sub-assembly components, reducing ‘down-time’ & maintenance costs.
The cockpit is enclosed by a high-quality, exceptionally-strong, composite fuselage. Many gyroplanes available today are fitted with a flimsy ‘fairing’ aimed at improving the airflow around, and the aesthetics of the cockpit area. The uTe sports an attractive, durable, lightweight, Carbon-fibre and Polycarbonate cockpit nacelle, which is also strong enough to offer the pilot a measure of protection in the event of a ground–manoeuvring incident or accident.
The aircraft can also be operated in a number of different cockpit configurations:
In the fully enclosed configuration, the uTe provides cockpit comfort-levels usually associated with much more-expensive, general aviation aircraft, while the option of removing the rear pair of cockpit enclosure doors improves rear-cockpit visibility and utility.
There is also the option of removing all four cockpit enclosure doors, creating a completely open-cockpit option.
Whether looking for more comfortable conditions on those cold, early-morning, cross-country flights or for flight in true open-cockpit aviation tradition, the uTe fuselage options covers every motivation!
The shape, location and dimensioning of the uTe empennage are of precise aerodynamic determination. The airfoil design and incidence of the large horizontal stabiliser (inverted NACA 2210 profile) compensates for the increased down-force ahead of the aircraft centre-of-gravity as airspeed increases, most notably at higher power settings.
The horizontal stabiliser generates increasing down-force (negative lift) as airspeed increases, thereby automatically providing a force of the correct magnitude and orientation behind the aircraft centre-of-gravity, to keep the aircraft pitch-attitude steady throughout the flight envelope!
Yaw stability is accomplished by having ample vertical surface-area designed into the empennage. This counteracts the considerable forces caused by airflow impinging on the large, closed cockpit structure should the aircraft be flown in a yaw out-of-balance condition – in such a scenario, the three generously proportioned vertical stabilisers keep the aircraft properly longitudinally-orientated!
The large vertical tail-surfaces and rudder also allow positive directional control in the hover-descent at low power settings, eliminating the uncontrolled yaw that many other gyroplanes experience in this flight-regime.
Extruded aluminium rotor
The extruded-aluminium, factory-balanced rotors are the toughest, most-resilient rotors currently available in production, anywhere. There are a number of these rotor-sets which have seen extensive service in the harsh conditions of ‘outback’ Australia.
Here, gyroplanes are used in mustering domestic animals under the most severe environmental and harsh operational conditions. Some rotor-sets have managed to accumulate over 2 500 hours without any sign of fatigue or failure!
Rotor design-innovation and manufacturing-process improvement efforts are continually underway in order to offer a number of rotor variations, according to the envisaged role in which the aircraft will be operated.