The Jabiru - Flyer magazine Feature Article
First impressions, so the saying goes, count. They can also be deceptive and so it was with the Jabiru. My first impression was that of a microlight trying to be 'real' aeroplane, a bit of a toy. The impression is reinforced as you first walk up to it: the wing sits at chest height, forcing you to crouch down to look through the windows, and the wheels, whilst being in proportion, look too small to be serious. Lift the cowl (two 'R' clipped 'over centre' latches on the sides, and spigotted retainers in the firewall hmmm fast, neat, and providing splendid access) and the engine Jabiru's own looks as it was made from scratch in some garden shed by a gifted amateur.
Closer investigation proves to be an eye opener. Designed and manufactured in Australia, it is type certified by the Australian CAA, with some 100 examples flying half of them being certified rather than home built examples. Used for flight training, they have built up a solid history of practical, safe, cheap flying and have been tested in service by all the average student PPL can throw at them. They have accumulated 45,000 hours of time in service with the highest time airframe now past 3,500 hours and a fair number coming up to 2,500 hours. They have had no serious injuries, and not one airframe or indeed wing- has been written off to date. At the moment, only kit versions are on offer in Europe, but it's on the cards that certified fly-away examples will be on sale in a few years time: Australian certification requirements don't exactly match those of JAR VLA, but they're close enough to make it relatively simple job.
Getting the kit
The kit is quite superb: it sets a standard in fast build kits that is hard to better. Build time is quoted as 600 hours a claim to set everyone's eyes rolling with a strong sense of déjà vu but the first UK builder completed his in three months of hard graft, including moving house in the middle of the project. Indeed, the partially completed Jabiru displayed at Cranfield last year (and the example we flew) had arrived just two weeks before going to the Rally.
Everything bar avionics, paint, and upholstery (although you do get upholstery patterns!) are included to build a plain vanilla VFR aeroplane. That includes the engine, prop, instruments, fasteners, all the systems, but not the battery although they do provide an order form for your local Yuasa supplier. The tools required are commonplace, and unless you have a hankering to do everything yourself, including painting and trimming, probably the only things you might feel the need to go out buy will be a set of Permagrit sanding blocks and the odd clamp. The manuals are excellent too, as you might expect when you find out that they were developed from the quality assurance manuals for the factory built types. Unlike many aircraft, which have both certified types (not that there's any discernible difference) and it shows.
The impression here is still overwhelmingly that of a model kit, and a simple one at that. The wings, ailerons, flaps, and tail surfaces are complete, and don't even need painting: they're already finished in gelcoat. The control surfaces do need to be installed, and the controls hooked up, but, but apart from bonding the fin and horizontal stabiliser in position, that's it for the flying surfaces. I have to confess to being green with envy as a Europa builder coming up on the year mark and not being that advanced.
The fuselage is split in two horizontally, and a great deal of the fitting out has already been done: all the internal structures are in place, including the wing spar carry throughs and mounts, seats, undercarriage mounts, central tunnel, and tank mount. All critical holes are drilled by the factory, removing any possibility of misaligning crucial items. It's very much a case of fitting out the systems and interior before bonding the top shell in place assisted by a locating joggle, and filling and fairing the joints between the fuselage and tailplane components. The majority of fibreglass work can probably be done in a couple of days, very much reducing your exposure to epoxy.
The firewall forward package is comprehensive and very well thought out, with carb heat, cooling baffles, and all electric components provided. The UK versions have, as standard, the 'optional' vacuum pump drive fitted to the engine, making the installation of a set of gyro instruments hardly more than a bolt on job.
There is one worthwhile option for really adventurous types: the 'bigfoot' undercarriage kit. This replaces the faired 400 x 4 wheels with unfaired 600 x 6 for the mains, and a 500 x 6 for the nosewheel. Set against the diminutive airframe, they take on the appearance of serious tundra equipment, although they reduce the cruise speed by 7kt. The small wheels seem to be quite up to the average grass strip (and, I'm informed, the average beach in Australia) although the fairings are probably somewhat fragile when it comes to ruts and rough ground. The landing gear is extremely well tested: despite the best efforts of hamfisted students with a propensity for landing on the nosewheel, no one has managed to break one yet.
Getting is a matter of backing yourself into the cockpit, sitting down, and swinging your legs in. It's a bit like entering Dr Who's Tardis; with 42" of shoulder room it's as wide as a Cessna 172, although clearly the accommodation isn't as spacious. It's fair stretch to the rudder pedals, and there was a surfeit of headroom so unusually tall pilots shouldn't have a problem. We flew on a fairly cold day, and as cabin heat hadn't been installed we both elected to wear bulky coats without any adverse consequences. By now it was becoming apparent that some particularly clever designing had gone into this aeroplane, simple solutions that work extremely well.
There's single central control stick just in front of a armrest, and while both pilots can't use the armrest at the same time, from an instructor's point of view the controls are at least accessible by the other arm and the stick doesn't impede entry. Innovative, at least on a certified aeroplane, is the use of teleflex cables for all flight controls. They work smoothly with low breakout forces, with the exception of the rudder system. This was probably the result of a binding bearing in the nosewheel steering (it's directly linked to rudder) coupled with not powerful enough rudder-centering springs, and presumably is simply a matter of tweaking. The teleflex controls were subject to an exhaustive study during certification to examine their reaction to extremes of contamination with dirt and water in exceptionally hot and freezing conditions. Further forward on the central tunnel is a single 'pull for on' brake lever, and a spring bias pitch trim lever. The throttles are a pair of levers sprouting centrally from the front of the seats, and once you've remembered where they are, feel quite natural. The flaps are controlled by a three position lever in the left wing root, with a stone simple detent and lock system: pull the lever inboard to disengage a stud from a hole, and slide it into the next position where it automatically engages.
The fuel tank is as simple as they get. A clear plastic moulding, it sits in the middle of the baggage bay with a quality indicator in the form of a white graduated tape stuck to the front of it. There's no mistaking exactly how much you've got down to the last drop .It does mean that baggage can be somewhat awkward to get at during flight, and unless you are prepared to fill the aft cockpit on top of the tank, not all that much stuff can be carried, but that would only be a concern if you wanted to take along a full camping and recreational kit. For normal day to day flying, or even pared down continental touring, it's quite sufficient. There are a couple of useful lockers under the seats, and as the doors are single skinned, there's plenty of room for map and odds-and-sods pockets.
The panel's options
The panel comes in two options. This example was fitted with the standard VFR type, with enough room for all that's required in the real world; but if you have a hankering for mini airliners fit, a wider option is available with a central avionics box. One nice touch, and an idea we'll happily appropriate, is the use of an RS in/out digital temperature monitor: the 'out' probe is fitted into the induction manifold, providing a very handy and inexpensive induction icing gauge.
Firing up the engine is quite straightforward: in with the two ignition systems and the aux fuel pump, and it fires on the button without drama. There's no mixture control the CV Bing carburettor is altitude compensating, but a choke is provided for cold weather. It's remarkably quiet, with the majority of the noise coming from the prop, both at low and high power settings. The throttle is a little odd apart from the fact that it's between your legs in that it's very sensitive off the idle, needing a small movement to increase the rpm quite a lot to get you moving, but a high power settings, it needs a large movement to reduce the rpm by a small amount .Having said that, you certainly do get used to it quite quickly.
Control during taxying is very direct, and despite no differential brakes, quite tight turns can be made on the pedals. I was a little ill at ease with the need to reach over to use brake with my other hand (I prefer to keep one hand on the stick on the ground, especially in windy conditions) but it's just another thing to get used to, and I don't foresee any problems with the system, even if it will make taxying something of a busy affair on crowded ramps. The pre-flight run-up is conventional, checking for a slight rpm drop with each ignition system turned off, and similarly for a drop with the panel mounted carb heat pulled on. Unlike other small fours particularly Continentals this engine doesn't seem to be at all prone to induction icing, something, I suspect, to do with the fact that the indication tubes run through the sump.
One notch of flaps is used for take-off: full throttle produces quite respectable acceleration, and despite having the trim set a little too nose down, a gentle tug at 45 knots allowed to Jabiru to fly itself off in under 150 metres with no drama at all. It was easy to remain glued to the centreline despite a mild (5kt) crosswind, and the controls feel natural right away. No need to check forwards, more the opposite in fact: the flap limiting speed is 70kt, and it's all too easy to exceed that if you're not paying attention. It climbs better clean, so pulling the nose up and retracting the flaps produced a solid 800fpm: very impressive. Solo take-offs are quite exciting; the acceleration is excellent, it will break ground in half the distance, and do a spectacular impression of a Maule with a climb rate approaching 1,200fpm. Initially, I wasn't too happy with the stick/armrest/seat position: trying it out on the ground felt a little awkward, with the feeling that the armrest was too high,and the stick too far aft, but an hour after flying the Jabiru I realised that I hadn't given it a second thought in flight. Hard manoeuvring requires you to move your whole arm around for full deflection, but for cruise, gentle pressure was all that was required.
Control harmony isn't exactly classic: the rudder is a little light, something perhaps compounded by a little stiction in the system, and elevator and ailerons are about equal in pressure. It is however, a great deal better than many other types, and has a natural feel to it. This is definitely a rudder aeroplane: if you don't lead with a little foot pressure into a turn, the nose will smoothly move in the opposite direction and reduce the roll rate by half. While some pilots might not like that, I think that it's a desirable characteristic for a trainer: most aeroplanes do it to one degree or another.
The roll rate is solid rather than sporty about the same as Cessna 152, but it does feel faster due to the light control pressures required. Stability in all axes is excellent both static and dynamic. Kick on the rudder, and the resultant yaw/roll damps out quickly without fuss. There is a strong yaw/roll coupling, and indeed, you can fly the Jabiru all day long on the rudder including turns up to 30° without touching the stick. Prolonged turns require either a little retrimming, or much easier, a small increase in power. Roll a wing down, and it just sits there . Point it on a heading, and it does the same: nice, and very comfortable for long distance cruising.
Making a stable platform
Pitch stability is as good, and perhaps the only thing to slightly spoil the effect was some slop in roll around neutral in the stick easy enough to deal with given a little engineering expertise. I was curious to see the if the slight stiction in the teleflex cables would have any adverse effect on the static stability in flight, the stick wouldn't return exactly to neutral if you deflected it and let go, but it didn't seem to be a problem in the least. This was probably the biggest surprise for me (or is that for my preconceptions?) on the Jabiru. It flies like a much bigger aeroplane, and whilst we didn't sample it in turbulence, I have no doubt that it will be as equally well behaved.
The stall behaviour is, if anything, too good for a trainer; power off, clear airframe buffet (from positively huge stall strips on the leading edges) preceded a gentle mush by around 5 kt, and holding the stick hard back produced a little nodding in pitch and no tendency to roll off just a clear descent. Relax the pressure and it's flying again. Stalls at cruise power resulted in a higher pitch angle and clearer buffet before a gentle break hardly more than lowering the nose half way to the horizon, and it settled into a gentle pitch buck. Eventually, perhaps 20 seconds after the break, one wing made a very half hearted effort to lower itself. Perhaps a little subtle for a trainer but at least it won't scare the **** out of novice pilots! While spins are placarded against in the UK, the aircraft has undergone full spin series testing in its native Australia.
Equally surprising was its performance. Set 2,600 rpm (max is 3,100) on the tacho about 75% power and it quickly settles on 105kt for a fuel burn of around 13 litres/hour. Three gallons an hour at 120mph that makes it better than twice as efficient as a Cessna 150. No wonder the flight schools are private owners in Australia love it. This is a cheap, practical, and affordable flying with no drastic trade-offs. Impressive.
Visibility is excellent in all directions except up: it would be nice to have a large skylight, but the roof is structural, so serious design work would be required to make that available. However, once you get into the habit of lifting a wing and clearing the direction of turn in advance, it's not really an issue.
Returning to the ground
Back in the circuit, the apparent slipperiness of the design proves not to be a problem. Speed can be held high, and the relatively low inertia allows you to reduce the ASI to the flap limiting speed fairly quickly. Flap pitches the nose down nicely, and despite the trim system not being adjusted to perfection (not enough nose up was available for a completely hands free approach) only light pressure was needed to maintain an approach speed of 65 kt on final. Speed stability is excellent, but throwing in a measure of slip reveals that it doesn't increase the decent rate much but at least it doesn't do anything untoward either, whatever the flap setting. The flare and landing is particularly easy as long as you keep in mind the fact that this is a low interia aeroplane, but approach a little fast, and it will float nicely too! With a little practice, you could comfortably operate the Jabiru from a 300 metre strip.
All in all, it's an attractive package: the price is right, the performance is excellent, and even the looks grow on you. I'm always a little dubious when a design appears with various aerodynamics fixes the stall strips, the ventral fin, and 'extra' fixed elevator tabs but the Jabiru really delivers the goods. The flight schools love it. It reduces the cost of flight training for student PPL's, and allows them better margins of profitability in a fiercely competitive market. It's certainly no toy, and the most telling evidence from a personal point of view comes when walking away from it, do I want to fly again? I'm already trying to come up with the excuses for the next time.