[Skywings]

Taken from Skywings July 1996

The Java is the latest glider form the Avian stable, developed over the last two years by Steve Elkins and his team as their first advanced/performance machine. It is currently being produced in 155sq ft size, with 15Osq ft and 14O sq ft models at the advanced prototype stage. Most of my test flying has been on the 155 reviewed here, although I have had some time on a mylar version of the 150.

The overall finish of Avian gliders is now one of the best, the sail and airframe being designed and built with meticulous detail. The weight of the Java is the first thing that you notice; it is pounds lighter than the competition and makes those long walk-ups just a little bit less painful. One thing to note is that the Java 155 doesn't look as mean on the ground as other high performance machines; it is not as tight and the nose angle is not as high. I wondered if this would mean that the performance wasn't up to scratch. Read on..

The Sail

One of the outstanding elements of Avian gliders has been attention to detail in sailmaking. Avian have focused on producing gliders with really clean sails that maintain their shape at all speeds. The Java continues with this trademark; the whole sail is wrinkle free on both the top and undersurface, with no sag or drumming at high speed. Just how clean the sail really is was brought home to me the first time I flew some 6Omph speed runs because the glider was so very quiet. No flapping or howling - it almost felt as though my ASI was not reading correctly.

The Airframe

Avian have made great strides in the construction of their airframes and I now rate them as one of the best around. The construction is not quite straightforward; the leading edge tubes are completely smooth, with recessed bolts and no external sleeving (to minimise sail damage and keep the wing aerodynamically clean), and feature a large step down to narrower than usual outer leading edge tubes. Rubber backed aerofoil uprights and shiny silver anodising are another Avian trademark, and the detail on a lot of the small parts adds up to a very well thought out machine.

The cross-tubes are joined at the centre via a ball joint so that the loads are transferred properly through the whole circumference of the tubes rather than via plates as on most gliders. In this assembly the bolt heads are inside the tube to prevent sail damage. The cross-tubes are tensioned by a strop that runs from one side of the keel, round the cross-tube junction to the other side of the keel, where it is mounted on a in and retained using a split ring in the same style as on Solar Wings gliders. The retaining bungie for the strop is doubled up so that the strop cannot get twisted inside the sail when rigging.

There is a very neat new side wire tang to prevent kinking in the wires and the wires themselves are single swaged; neater and according to the industry and BSI - better than double swages. The glider comes as standard with a strap around the keel at the nose to hold onto when rigging, so you don't have to undo the undersurface zip to grab the keel.

The VB system is mostly mounted behind the kingpost in the small keel pocket, and consists of two triple pulley blocks (with dual ball bearings) and a sealed ball bearing unit pulley at the cross-tube, giving a 12 to 1 reduction. This is expensive kit, but well worth it as the effort required to pull the VB on is minimal. The tip batten is a development 0f the Amour batten, but curves with the sail to perform the functions both a tip batten and a tip rod, reducing e weight and thus inertia at the tips to help the handling. Reassuringly, it can only be put in the right way up. The Java has locking tips for tuning turns out and the leading edge tension can be changed by use of shims.

There is packing in all the right places, with bags to cover the rear rigging mounting point and the end of the keel (keeps the sail clean!).

Rigging

The glider is easy to rig with 9 top surface and three undersurface battens on each side. On the ground with no VB on the glider is very slack, so much so that it gives the impression of not being rigged correctly when you first see it, but as soon as some air begins to flow over the wing it looks fine. The lower side wires have a fair amount of slack with no VB on.

Ground handling

If ever an aspect of a glider was given the full Eurovision ten points, this would be it. The ground handling is excellent. The static balance is very slightly tail heavy, making it easy to hold at the right angle of attack, and if a wing drops a bit of side pressure is all that is required to level it. I ground handled it on a very turbulent wave-affected day in Derbyshire when I would normally have been putting the glider down every few seconds to stabilise it, but I was able to walk I00 yards across the hilltop with the Java without having to put it on the A-frame once. Half VB helps here as it takes some of the slack out of the side wires.

Take-off

Taking off is not difficult and the handling is good enough at slow speeds to instil great confidence. One thing to watch is that the glider is not very fast with the VB off, so taking off on windy days is better with at least a third of VB travel applied.

In Flight

I am at the bottom of the weight range for the Java I55 (I0st 8Ib in my birthday suit). As you would expect from a glider that is light and has little weight at the tips the handling is very good. There is a slight yawing tendency with the VB off at around 30 - 35mph, but this all but disappears when some VB is applied. The stall with my weight occurs at I7mph, requiring a firm push to actually drop the nose. If you push out progressively the glider reaches I7mph and starts to 'walk' from wingtip to wingtip without actually dropping the nose. This has consequences on landing which I will cover later.

The sink rates I experienced during testing seemed to be excellent. In dynamic lift the Java is a glider that regularly seems to be near the top of the stack whoever is at the controls, and this is the same in thermals.

Thermalling was great fun, and once established in a thermal you can control the position of the glider very accurately. The feedback from the glider on the air around it is also very good, and once 'tuned in' gives you a good feel for the surrounding air. One situation which needed quick reactions was when I hit a strong thermal with a big surge under a wing; it took some effort to start the wing going down in the desired direction. Once the wing is rolling it is easy to turn into the thermal and start climbing, but a good dose of muscle power at the start is required. The VB has a marked effect on the performance and feel of the glider and with full VB it is very stiff indeed. The VB also affects the amount of high siding required to thermal and it can be used in thermals to tune the glider for minimum effort, but mostly I flew with the VB about a third on in thermals.

Once topped out in the thermal, pull on the VB and the glider really feels different. If you try to glide with the VB off you can feel the drag holding you back; pull the VB on and you can feel it disappearing. A number of manufacturers have made gliders (especially Icaro's Laminar and Moyes' Xtralite) that are very slack with the VB off for handling and can be made very tight for gliding. The Java has been designed with the same attributes and the difference between the VB on and off settings is significant. Incidentally, the VB is so easy to pull on that you do not even have to move your left hand to resist the pull of your right. In practice this means that you pull the VB on and off much more often than usual and even if you are only gliding a short distance you can use it without penalty. The VB rope jams in a yachting cleat and can be released with a quick tug.

Gliding with VB full on was hard work. After letting the VB off performance the glider likes to glide at 32mph, and feels best at this speed. Higher speed glides up to 50mph also feel really good and it seems to match the best of the rest, but only after a few big competitions will we really see how it goes. In all the UK flying I have done on the Java so far it appears to be an excellent performer in glide. I flew it in company with the latest group of hot ships on a day where the wind was howling (35 to 42mph on Rushup top take-off!) and was able to cruise around the sky at no disadvantage.

The highest sustainable speed on my ASI was 62mph (I00km/h), but it would go even faster it you lifted Four knees up to your chin!

Landing

The Java is very straightforward to land in all but nil wind. It handles well and has a fairly wide flare window. If you want to land it in high winds it is worth remembering that the top speed is significantly reduced with the VB off, so it's wise to not get out of position behind walls and trees, etc, or to keep the VB on at least a third for landing in strong winds. landing in light winds requires a little more finesse, as to stop the glider dead you have to time the flare correctly. In nil wind you can get the flare timing wrong and still do a good landing if you are Prepared to run. If you leave the flare really late, the glider will gently, drop a wing, but I have yet to do a had Initiating of the glider.

A major advantage of the super-slack sail is that if you want to land in a small landing field you can make an approach similar to that of a low performance machine. Because the glider does not glide well with the VB off, if you pull the bar in you fall out of the sky rather than gliding on and on