Pilot Handling Notes for the I.S.-30, Vh-Gqa

PILOT HANDLING NOTES FOR THE I.S.-30, VH-GQA

(These notes have been drafted to assist pilots preparing for conversion to the type. They do not replace the published aircraft operating manual which all pilots are required to read before converting to type and which is the only authoritative document relating to the operation of the aircraft.)

Cockpit load

Particular note should be taken of the maximum cockpit loading in the IS30. Max cockpit load is 161 Kg for general flying and 91 Kg for aerobatics.

Canopy care

The IS30 canopy is very susceptible to rough handling as evidenced by the numerous crack repairs. One of the main causes is from reaching in through the windows to release the rope whilst the aircraft is being towed to or from the launch point. Inadvertently flexing the window cut out with your forearm as you try to keep up with the tow vehicle and pull the release is the problem. Another problem is checking that the canopy is locked prior to flight. Push upwards on the canopy frame, NOT the window cutout.

Ground roll and takeoff

In order to achieve a smooth takeoff you should try to balance the glider on the main gear during the ground roll. Initially this can be quite difficult due to the small pitch change between having the nose wheel on the ground and having the tail wheel on the ground. Care must be taken not to oscillate between the nose and the tail as this can rapidly degenerate into full-blown PILOT induced oscillation (P.I.O.). The main wheel is placed very close to the centre of gravity, therefore depending on cockpit loading the takeoff may commence with the either the nose wheel resting on the ground (dual) or the tail wheel resting on the ground (solo).

Commence the takeoff with a little forward or back stick as required to balance on the main gear. Avoid dragging the glider into the air before it is ready to fly by applying back stick too early. This increases the amount of drag produced and actually retards tug acceleration. It is considered very bad practice. No aircraft should be forced to fly before it is ready. Likewise avoid prolonging the ground roll by holding the nose wheel on the ground, as this can be very hard on the small nose wheel. It may also result in a very abrupt lift off when the nose is eventually raised. Again this may lead to PILOT induced oscillation.

For more experienced pilots flying in crosswind conditions it can be advantageous to briefly hold the nose wheel down to aid in directional stability, however this is not a novice technique. If the glider is held in a slightly tail down attitude whilst balancing on the main gear it will gently become airborne of its own accord once sufficient speed has been attained. This technique works on all gliders and is the mark of an accomplished pilot. (Notice that the word "pilot" is in capitals when referring to PIO. This is to emphasise that it is the pilot who induces an oscillation, not the glider.)

Controllability

The I.S. 30 is a heavy aircraft in comparison to the Blanik. Each wing weighs approximately 116 Kg and this provides a great deal of inertia particularly in the rolling plane. The pilot will notice this firstly as a lack of aileron authority at low speed and secondly as a reduced roll rate. If a wing is suddenly displaced by a gust or the tug's prop blast then you may notice that it takes considerable effort to level the wings. This is simply a characteristic of the glider and is, in itself, a good precursor to more advanced aircraft.

Learn to anticipate situations that may displace you from a wings level attitude. Watch the tug for clues to wind gusts. This is a particularly useful method when taking off from runway 06 (Caboolture) with a SE crosswind. It is not unusual to encounter some wind curl over once you are abreast of the hangars. The earlier you can catch the right wing as it goes up the less dramatic it becomes.

The view from the cockpit is considerably different to that from a Blanik. This is due to the lower canopy waistline and a more reclined seating position. Bear this in mind as the horizon may at first appear to be higher in the canopy and this could be misinterpreted as a prompt for the inexperienced pilot to make abrupt and inappropriate speed changes, which in turn could lead to pilot induced oscillations.

The elevator is quite powerful as would be expected of an aerobatic aircraft. Once established in the tow the '30 doesn't exhibit any noteworthy characteristics apart from the trim control.

Trim

The trim control is of the spring bias type and is mounted at the base of the control stick. Unfortunately it has insufficient authority to trim fully back at maximum cockpit load. You may therefore have to fly with some stick load. It is probably the most negative aspect of the aircraft from a pilot's perspective and whilst it is not an ideal situation it does become bearable with practice. When flying solo it is not as noticeable.

Co-ordination

Possibly one of the first things you may notice is that it is more difficult to keep the yaw string centred compared to a Blanik. The Blanik is regarded as having well harmonised controls. ie The relationship between rudder and aileron is nicely balanced.

In the I.S.30 you tend to 'run out' of rudder if you use full aileron deflection, so if you are competent at rolling accurately into a thermal using large rudder/aileron inputs in a Blanik, then you may initially wonder why you are slipping into your turns in the '30. During your training you may have been taught to centre the yaw string with the rudder and generally in a Blanik you have sufficient rudder authority remaining to do this. You may well have learned by this stage that the yaw string can also be straightened with the ailerons, or a combination of both controls. In turbulent conditions and in more advanced aircraft this is a valuable skill. A few flights to familiarise yourself with this characteristic is generally all that is required.

Speed control

The I.S.30's design produces significantly less drag than the Blanik and this feature means that small changes in attitude result in large changes in speed. Whereas 70 knots in a Blanik is the result of a noticeably nose down attitude this visual cue is not as apparent in the I.S.30. A momentary lapse in attitude control can result in very rapid speed build up. Modern high performance gliders are characterised by very large (and rapid) speed changes with very small changes in attitude, therefore this is an essential competency that must be mastered.

At the other end of the speed scale is the stall and spin.

The straight stall

Depending on the rate at which the pilot initiates the stall, there may or may not be any noticeable pre-stall buffet. At maximum cockpit load the stall occurs around the 40 knot mark and rudder/aileron control can generally be maintained down to this point. If the stall is brought on more rapidly and a higher nose attitude is attained, then there is a distinct "break" followed by the nose dropping sharply. Standard recovery procedures apply. Ease the back pressure and recover from the resultant dive. Unless the pilot performs an aerobatic stall entry then speed build up and height loss is minimal.

The incipient spin

Being a mild mannered trainer, the Blanik usually has to be provoked into dropping a wing and it is usually accompanied by a recognisable pre stall warning in the form of mild buffeting. It also becomes noticeably quiet.

The I.S.30, on the other hand, can sneak up on the unwary pilot without any obvious warning. One minute you are thermalling happily, the next you are pointing at the ground and the inside wing has started to tuck under. Left unchecked, auto rotation will commence or a transition to a spiral dive may occur. In this aircraft SPIN RECOVERY MUST BE BY THE BOOK. Where the docile behaviour of the Blanik will tolerate a less than perfect recovery technique, the I.S.30 will not. Again this is a level of competency above the basic trainer that readies you for the transition into more advanced aircraft.

The full spin

Depending on entry mode, the fully developed spin varies from predictable and conventional through to abrupt and steep. Entry from a normal thermalling attitude by steady backward movement of the stick combined with coarse use of the rudder results in a predictable departure about the stalled wing followed by auto rotation if full control travel is maintained. Normal recovery procedures are immediately effective.

If a more enthusiastic effort is made resulting in an "over the top" or very nose high entry then the wing drop is more sudden and the attitude appears steeper. If the spin is prolonged, the nose down attitude may oscillate past the vertical. In this situation when you apply the spin recovery control inputs there may be a brief pause before the recovery commences. This may be a little disconcerting at first, but as long as you maintain the recovery inputs, all will be well.

A note of caution: Once the rotation has stopped, you may find yourself in an extreme nose down attitude. During the pull out speed and/or structural ("g") limitations could easily be reached, hence the requirement for the correct recovery technique. Height loss can also be dramatic, so if fully developed spins are intended then make sure you have sufficient height.

Circuit

As stated above, speed control requires more skill. This is never more important than whilst low to the ground.

Final approach, flare and land.

Glide path control is conventional. Maintain aiming point (glide path) with left hand (airbrake) and speed control with right hand (elevator) as is normal practice. The airbrakes are very effectivewhen fully deployed.

Caution: During the check 1 and check 2 phase of the landing, be very cautious of opening additional airbrake as you flare. The increase in wing angle of attack not only produces an increase in lift, but it is also accompanied by a large increase in drag. If this condition is combined with an increase in airbrake then you may be unable to arrest your descent rate sufficiently to prevent a heavy landing. Until you become accustomed to this characteristic it is best to hold your airbrake setting when close to the ground and complete the landing with elevator control.

It is easy to over flare and touch down tail first. Due to its weight, the I.S.30 carries a lot of energy through the landing process. No pilot should routinely rely on the wheel brake to shorten the ground roll, though when operating it is quite powerful. Unlike the Blanik you can apply the wheel brake to the point where the glider rotates onto the nose wheel. This can actually aid directional control during the ground roll provided you are pointing where you want to go! The ability to regularly perform low energy, accurate landings in the I.S.30 is a skill worth attaining.

Performance

For such a seemingly heavy glider, it is surprising how well a competent pilot can remain airborne in very weak conditions. A lot of people are initially disappointed with the I.S.30 because it is a heavier aircraft. The poor trim control doesn't help. After a few flights though, when these aspects have been mastered, you will most likely find the I.S.30 quite pleasant to fly. For local soaring its ability to remain airborne is at least as good as Blanik. Where it is significantly better is its ability to allow you to be more selective with the thermals you use because you have the performance to go and search further afield. As a transition aircraft, the I.S.30 exhibits enough characteristics to adequately prepare you for higher performance single seaters.

Performance Summary

Min solo pilot weight / 59 kg
Maxsolo pilot weight / 110 kg
Max fuselage load / 161 kg
Max fuselage load (aerobatics) / 91 kg
Never exceed speed / 135 kts
Never exceed speed (aerobatics) / 121 kts
Max rough air speed / 86 kts
Max aero tow speed / 75 kts
Max winch speed / 67 kts
Max speed air brakes open / 121 kts
Stall speed (75 kg, solo) / 35 kts
Stall speed (75 kg, solo, air brakes deployed) / 38 kts