Dominator Autogyros

Autoflight Reduction Gearboxes

NZ Dominator Features

Click any picture for an enlarged view

115 hp SUB4 Engine
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We recommend and supply SUB4 engines. These engines are designed specifically for the recreational aircraft market and are manufactured in Hamilton, New Zealand. Subaru EA81 engines are a favoured option for many recreational aircraft builders, however although these engines are light, rugged and dependable, they suffer a number of shortcomings which limit their true potential in this environment. For example, Subaru designed the original EA81 engine with siamesed inlet and exhaust ports. This, coupled with a long and poor flowing inlet manifold, significantly restricted the engine's output.

The SUB4 company have addressed this issue by designing and manufacturing new dual port cylinder heads which feature two sparkplugs per cylinder. These high flow, high compression heads utilise larger inlet valves which when used with SUB4's revised camshaft design and tuned inlet manifolds, combine to significantly increase the engine's BMEP (brake mean effective pressure), delivering a wide, smooth torque band and 60% more (dyno proven) horsepower. SUB4 engines are also supplied with a full electronic dual ignition system and a compact 4 into 1 exhaust manifold. These modifications make the SUB4 engine the clear leader of its class in the recreational aircraft market with an excellent power to weight to cost ratio.

SUB4 Gear Reduction Drive
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This 2.21:1 reduction drive is specifically designed for aircraft use by SUB4 to mate elegantly to an EA81 block without any need for adaptor plates. The cast aluminium housings are made from LM25 material heat treated to T6 standard. The gears are manufactured from EN39B case hardened to 60 Rockwell and run in an oil bath. The gear shafts are supported by ball and needle bearings throughout. This compact gear drive includes a replacement lightweight aluminium flywheel and rubber cush mechanism to ensure a smooth drivetrain. As per the SUB4 engine, this unit exudes quality and is our first choice for all Dominator powerplant installations.

Wheels / Brakes
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Our Dominator wheels are made from spun cast high tensile aluminium alloy and are fitted with quality ball bearings and tubeless tyres. Dominators taxi using differential braking. We manufacture and fit a light weight, but powerful and smooth disc braking system. The right most picture shows the heel operated right brake lever situated below the rudder pedal.

Tall Tail
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Our full flying fibreglass tall tail is moulded around a full length vertical aluminium spar pivoting on quality ball bearings. The tail is foam filled and comprises a generous, aerodynamic horizontal stabiliser located in the prop wash on the thrust centreline. Horizontal stabilisers should always be mounted in the prop wash to maximise their effectiveness and the stability of the aircraft at all flying speeds. Tall tails designed in this way automatically correct torque roll and also serve to decrease thrust losses by helping straighten the airflow coming off the propeller. The right picture shows the rudder trim tab system which serves to provide self alignment of the rudder with the relative airflow as well as positive feedback to the rudder pedals.

Centreline Thrust
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Even judging this picture by eye, you can see that the Dominator thrust line passes through or slightly below the centre of gravity of the aircraft. This feature is of critical importance to aircraft stability and safety. The centreline thrust configuration of the Dominator provides a significant point of difference to many other autogyro designs and helps place the Dominator at the leading edge of modern autogyro development.

Pneumatic front suspension
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We fit a robust but light weight, pneumatic telescoping front strut with a resonance damper to both single place and tandem Dominators. Enlarge the pictures to see the effort we take to machine strong but light components for both the strut and also the seat attachments.

Tandem Seating Configuration
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The tandem seating configuration is an important design feature for two reasons. Firstly this significantly reduces airframe drag over the alternate side by side arrangement. As well, both pilot and passenger can travel comfortably without being squashed together. The second benefit relates once again to aircraft stability and safety. The passenger (in the back seat) sits approximately on the aircraft's centre of gravity. This means that the balance, control and attitude of the aircraft doesn't change depending on the presence (or weight) of a passenger.

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Dominator's can be configured with either a small instrument pod, providing the pilot with an unobstructed view in all directions for a "flying armchair" effect. Alternately we can supply a semi-enclosure with windscreen. The area behind the screen and pod has quite still air and is completely effective for the pilot who desires wind protection. We will not supply and do not recommend fitting full enclosures to any pusher configuration (prop behind aircraft) autogyros. Such a configuration exposes the aircraft to unnecessary yaw stability and therefore safety issues.

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Our seat mounted throttle controls are comfortable to operate and very smooth due to the use of teflon lined cable. In the tandem machine we fit dual push-pull cables which provide a feature of un-restricted rear seat access, compared to the traditional mechanical rod linkages which always restrict access to one side of the aircraft. The left picture shows the integrated control for our mechanical pre-rotator option.

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Our Dominator's use light weight aluminium radiators and plumbing. We purposely locate the radiator above the thrust line to help raise both the aircraft centre of gravity and centre of drag. This has the added feature of allowing a simpler and more elegant plumbing system, which we also fabricate from aluminium for light weight.


Our standard pre-rotator will readily spin 25 foot Dragon Wing rotor blades in excess of 240rpm, or 28 foot blades on the tandem machine in excess of 200rpm, making for comfortable short field takeoffs. We have custom built mechanical pre-rotators for some customers that spin 28 foot blades over 250rpm.

Dragon Wings

All Dominators are fitted with high performance Dragon Wings rotor blades. These bonded and trailing edge riveted aluminium blades are the lightest and most efficient on the market. The bonding process utilises American military aviation spec. adhesive and autoclave curing to ensure absolute adhesion integrity. Dragon Wing rotors are supplied with correctly sized teeter towers and a pre-coned hub bar.

Trim System
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Tandem Dominators are fitted with an in flight adjustable electric trim system. This allows the stick to be trimmed to neutral load regardless of the chosen cruising airspeed.

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These pictures show a sample of components supplied for tandem Dominators. All steel componentry is 4130 grade aircraft tube. All aluminium is 6061 T6 specification. We use only aircraft quality control rod ends. All hardware is aircraft grade AN certified. All welding is eutectic tig or high tensile steel braze. You can be assured that your aircraft is built with first class workmanship and genuine aircraft materials.

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With all Dominator aircraft we supply instruments for oil pressure, oil temperature, water temperature, a tachometer and an hourmeter. Because of the large variety available and customer preference, we do not supply flight instruments but are happy to recommend suppliers if required. The owner of the aircraft pictured has fitted an electronic engine monitoring system. The buttons on the stick control the electric trim motor.