Flyer magazine engine report March 1997

The Jabiru was originally designed and certified in 1991 with the KFM112M engine from Italy. A month later, the engine manufacturer decided to cease production. Rod Stiff, the Jabiru's designer. Looked at the alternatives and decided that nothing available really suited his needs, and sat down with a clean sheet of paper to design the Jabiru engine. The result it something of a stunner that is making all other light aircraft engine manufacturers look uneasily over their shoulders. They are, I believe, the only manufacturer of both an airframe and engine at the moment.

Let's start with some raw numbers. The installed weight – including all necessary firewall forward equipment (cooling components, exhaust, mount, starter, alternator and so on) – is 56kg, the same as a 65hp two-stroke Rotax 582. That's 25kg lighter than the Rotax 912 of the same horsepower. The purchase price is similarly low: £5,950 + VAT, including all the firewall forward stuff – the Rotax 912 comes closer to £10,000 by the time you have sorted out all the other gubbins you need. Noise levels and fuel consumption are comparable, but the complexity – or lack of it – is definitely in the Jabiru's favour.

Current TBO – overhaul periods – are 600 hours, but it's on a rolling development programme so by the time you've accumulated that much time it should be up to 1,000 hours plus. Overhaul costs are fixed at £1,250, including labour. Quite how they do this becomes apparent when you compare components costs: Jabiru pistons and cranks cost about 30% of Rotax items, and the valves around 15-20% if the Austrian items.

The engine is beautifully simple: It's direct drive, and air cooled – no gearboxes, coolant pumps, radiators, and catch tanks. It's a conventional pushrod operated flat four, and is very unusual in that virtually all components- those not bought in – are machined from solid billet on CNC machinery. Over the life of the engine, this transpires to be the cheapest route, once you have taken into account modifications and materials tracking (for certification). Some components – pistons, valves, and cam followers – are sourced from automotive manufacturers (principally Honda and Toyota) and modified to suit.

It utilises a single Bing carburettor of the same type fitted to the 912 (which uses two of them), a permanent magnet alternator, and two completely independent transistorised self generating ignition systems: other than the occasional clean, they are maintenance free.

One really nice touch is a separate prop flange: it's bolted to the front of the crankshaft, and in the event of a mishap, it gets replaced if it gets bent – rather cheaper than a sudden stoppage inspection and a new crank. In one case in Australia, where an over-enthusiastic pilot landed on a wet beach and flipped the aeroplane, the (sand filled) air filters and prop were replaced, and the aircraft flown out. The only other damage found was a scrape in the paint on the top of the fin.

If the 2200 wasn't enough to cause other manufacturers sleepless nights, in the next year or so, the 3300 will be ready: a 6 cylinder engine of 120bhp, it will still weigh less than the Rotax 912, and word has it that it will still be cheaper.