Jabiru engines have been flying for over two decades in certificated, experimental and light-sport aircraft all over the world. The early 65-80 hp models were designed specifically for the first Jabiru aircraft, the LSA 55/2K. With the success of the first four-cylinder 65-hp engine, it became an obvious choice for other aircraft manufacturers and kitplane builders to fill the need for a reliable alternative to automotive conversions and 2-stroke engines. With the release of the 6-cylinder, 120 horsepower model 3300, Jabiru’s market expanded into the range of the popular 100-125 hp used certificated engines while shaving up to 50 pounds off the firewall-forward package. Now numbering well over 6,000 engines worldwide, Jabiru engines fly hundreds of thousands of fleet hours each year for recreational flying and flight training operations. The years of experience have given Jabiru engineers unique insight into ways to improve the durability and reliability of the engine design, making today’s Jabiru engines some of the most reliable engines ever produced for light aircraft.
We not only sell Jabiru engines, we also fly them and maintain them. Our aircraft use total-engine electronic engine monitoring as standard equipment to fine-tune the performance, cooling and fuel mixture spread in all regimes of flight. As a result, we know exactly what’s going on inside all of our engines from the moment of first startup, and have been able to fine-tune our firewall-forward kits for optimum performance.
Over the years, we have designed firewall-forward kits for many popular kitplanes, providing builders with everything they need to install their Jabiru engine. Typical firewall-forward kit components include the cowling, engine mount, battery box, air filter, cabin & carburetor heat, propeller, and spinner.
Philosophical Differences: Physics vs Electronics
In today’s age of electronic systems mania, Jabiru remains steadfast in its belief that an aircraft engine should not have to rely on an outside source of electricity to run. The ignition and fuel delivery systems are both completely independent of the aircraft’s electrical system, eliminating the need for backup batteries and alternators. This setup has given pilots reliable and efficient operation for over two decades and hundreds of thousands of flight hours, while retaining the design goals of simplicity and light weight for today’s light aircraft.
Engine Construction Details
From the Jabiru Aircraft PTY LTD website:
Jabiru engines are designed to be manufactured in small batch quantities using the very latest Computer Numerically Controlled (CNC) machine tools. The vast majority of the components are manufactured in Southern Queensland in a network of high technology small companies. The crankcase halves, cylinder, crankshaft, starter motor housings, gearbox cover (the gearbox powers the distributor rotors) and coil mounts together with many smaller components are machined using the latest CNC machine tools. The sump (oil pan) is the only casting.
The cylinders are machined from solid bar 4140 chrome molybdenum alloy steel, with the pistons running directly in the steel bores. The crankshaft is also machined from solid bar 4140 chrome molybdenum alloy steel, the journals of which are precision ground prior to being Magna flux inspected. The camshaft is provided by a specialist camshaft manufacturer.
The propeller is directly crankshaft driven and does not use a reduction gearbox. This facilitates its light-weight design and keeps maintenance costs to a minimum. The crankshaft features a removable propeller flange which enables the easy replacement of the front crankshaft seal and provides for a propeller shaft extension to be fitted, should this be required for particular applications. Cylinder heads are machined from solid aluminium billet which is purchased directly from one of Australia’s largest aluminium companies, as is all alloy used in the engine, thereby providing a substantive quality trail to material source. Con rods are machined from 4130 alloy steel, the 45mm big end bearings are of the automotive slipper type.
An integral alternator using rare earth magnets, provides alternating current for battery charging and electrical accessory drive. The alternator is attached to the flywheel and is driven directly by the crankshaft. The ignition system is a transistorised electronic system; two fixed coils mounted adjacent to the flywheel are energised by rare earth magnets attached to the flywheel. The passing of the coils by the magnets creates the high voltage current which is then transported by high tension leads to the centre post of two automotive type distributors (which are simply rotors and caps) before distribution to automotive spark plugs, two in the top of each cylinder head. The ignition system is fixed timing and, therefore, removes the need for timing adjustment. It is suppressed to prevent radio interference. The ignition system is fully redundant, self-generating and does not depend on battery power.
The crankshaft is designed with a double bearing at the propeller flange end and a main bearing between each big end. It therefore does not have flying webs. 48mm main bearings are also of the automotive slipper type. Thrust bearings are located for and aft of the front double bearing allowing either tractor or pusher installation.
Pistons are Jabiru designed. They are manufactured by a specialist piston manufacturer. They are fitted with 3 rings, the top rings being cast iron to complement the chrome molybdenum cylinder bores. Valves are 7mm (stem dia) which are purpose manufactured for the Jabiru engine.
The valve gear includes push rods from the roller follower. Valve rockers are forged, through hardened and mounted on a shaft through a pressure lubricated bush. Valve guides are manufactured from aluminium/bronze. Replaceable valve seats are of nickel steel and are shrunk into the aluminium cylinder heads. The valve gear is lubricated from the oil gallery via the hollow push rods.
An internal gear pump, direct mounted on the camshaft and incorporating a small automotive spin-on filter, provides engine lubrication. An oil cooler adapter is provided. All installations require an oil cooler to meet oil temperature limits.
The standard engines are supplied with two RAMAIR cooling ducts, which have been developed by Jabiru to facilitate the cooling of the engine and direct air from the propeller to the critical areas of the engine, particularly the cylinder heads and barrels. The fitment of these RAMAIR cooling ducts is a great bonus for the home builder or engine installer, as they obviate the need to design and manufacture baffles and the establishment of a plenum chamber, which is the traditional method of cooling air-cooled aircraft engines. The fact that these baffles and plenum chamber are not required also ensures a “cleaner” engine installation, which in turn facilitates maintenance and inspection of the engine and engine component. So the hard work of engine installation has largely been done for you by the Jabiru design team. RAMAIR ducts are available for tractor or pusher configurations. Special ducts are available for certain installations.
The engine is fitted with a 1.2 kw starter motor. The engine has very low vibration levels, however it is also supported by four large rubber shock mounts attached to the engine mounts at the rear of the engine. An optional bed mount is available.
The fuel induction system comprises a BING pressure compensating carburetor. Following carburation, the fuel/air mixture is transported to a small plenum chamber in the sump casting, in which the mixture is warmed prior to entering short induction tubes attached to the cylinder heads.
An effective stainless steel exhaust and muffler system is fitted as standard equipment, ensuring very quiet operations, which in the Jabiru aircraft have been measured at 62dB at 1000′ full power flyover (for 2200 engine).
For those owners wanting to fit vacuum instruments to their aircraft the Jabiru engine design includes a vacuum pump drive, direct mounted through a coupling on the rear of the crankshaft.
Jabiru engines are designed and manufactured to ASTM F2339 and within quallity assurance standard ASTM F2279 as well as to Australian Civil Aviation Safety Authority (CASA) approved Quality Assurance System exacting standards. Jabiru also holds a Production Certificate and Type Certificate for the 2200C engine.