I have seen over many years that various sport aviation developments seem to occur in steps. This is where a slow refinement of the various designs, is followed by a significant jump in handling or performance. One manufacturer starts it off, with the rest following suit very soon afterwards.

The Esqual is one such development.

The Kit
Kits are all different. They use different materials, some are easy to build and others require a lot of background knowledge or skills. They may be fast or slow to build, the instructions vary in quality, some have good factory support, and some not.

It is one thing to design a very high quality aircraft, but designers need to also design it for simple amateur construction. The Europa is a classic example of this omission - the design is really professional, and the end result is outstanding, but it seems to take those that actually finish their aircraft, an average of around 5 years to get flying. Some are still building after 7 years! As many builders are retired, time could be against them ever getting to fly such a kit.

In a well thought out glass kit, the manufacturer can design to simplify the structure and controls, and with no extra work at his end, can also save the builder an enormous amount of work. As an example, the introduction of wing stubs to the fuselage moulding, can save a few hundred hours to a builder who would have to contour the wing and flaps to the compound curves of the fuselage, and fit his own fairings as well. Also, to make precision mouldings for the glass components, so that one doesn’t have to spend endless hours filling and smoothing bumps and hollows, and reshaping mould errors.
The Esqual factory has done just this, resulting in a quick build aircraft with exceptional flying qualities. A builder should be able to finish his aircraft in 12-18 months of part time work, which seems to be what most prospective builders regard as acceptable. The Esqual is still a fledgling in production, and this test aircraft is from the early production runs. It is too much to expect that first runs of kit aircraft are perfect. These are usually refined as experience is built up, and by customer inputs. The Esqual is no exception.

The fibreglass mouldings for this kit would not be out of place in a sailplane factory, as they are so precise. However the instructions, detail engineering, and a few missing items, while better than many kits, could be upgraded further. As I said, this is an early kit and it is a year or so since the kits were despatched. The factory has been quick to replace missing parts, and has sent out upgraded items without being asked, at no cost, so I would be surprised if deficiencies have not already been fixed.

The factory seems to be a real go ahead place, as they are test flying a retracting gear taildragger, designing a tricycle retracting version, are developing newer faster wings with unchanged stall speeds, have in production another longer winged kit for the European market, and are now producing a lighter carbon fibre version with a VNE of 184 knots!

General Description
The aircraft tested is a low wing with fixed tricycle undercarriage. It has 27 ft long tapered wings with a relatively narrow chord. The wings, ailerons, and flaps are reflexed for high speed flight. The electric fowler flaps are huge in depth, and take up most of the length of the wing. This results in extremely low landing speeds. They extend to 45°, although 30° is more than enough for normal operations. The ailerons on the other hand are narrow, but make up for a lack of width by being very deep, and in addition are slotted, which is an unusual refinement in a kit aircraft. The horizontal tailplane is conventional and without trim tabs, which simplifies the build process. Tabs are not needed, as the light range of control forces are perfectly handled by the spring trim.
 
This aircraft is designed so that any changes to its carried weight has minimal effect on the CG. In other words the pilot and passenger and luggage are all concentrated around the CG, with the wing fuel tanks also being positioned closely, if not on the CG. You don’t have to worry about how you load the aircraft.

The engine compartment is roomy, with lots of space to access everything. The cowlings are quite simple and clever, with the front being hooked in first, then the back is lowered and held by a few screws. It is also an example of good design saving heaps of work for the builder.

Cockpit and Ergonomics.
Seating position is side by side in a cavern of a cockpit, capable of seating just about any pilot in comfort. Rudder pedals are adjustable within wide limits to accommodate any leg length and are fitted with hydraulic differential toe brakes for both braking and steering. The seats are extremely comfortable, being premoulded by the factory, with removable cushions, and semi reclining in the fashion of modern sailplanes. Two people could sit side by side in the metre wide cockpit all day without bottom or back discomfort. Controls fall to hand easily, and the large instrument panel is easily within reach. The dual throttle controls are fitted on the left cockpit wall, and in the centre console. This means that pilots can fly the aircraft left or right handed as they prefer.

Visibility on the ground is good for a low wing aircraft. The long thin nose gives plenty of straight ahead visibility, with very good visibility to the sides. The wing is mostly in front of the cockpit, but because the chord is relatively narrow, the forward view is quite good, and visibility behind the wing is even better. The in-flight view is unchanged.

There is a large luggage space behind the seat, which could be expanded even further by lowering its floor during the build process.

Flying
Two up, tanks 80% full - empty equipped weight 312kg with about a 200kg load. Temps about 23°C. Flown at 2500ft. Fitted with a Rotax 912S (100hp) with an Airmaster constant speed 3 bladed prop, with tapered Warp Drive blades.

Takeoff
Steering on the ground is easy by the very effective toe brakes, with the fully castering nosewheel allowing for turns virtually around one wingtip. 15° flap was selected for take off. The ground roll shows good directional control from the rudder. Acceleration is very rapid giving a ground roll of 7 seconds in nil wind to 40 knots, and an immediate transition to the full climb.

Flapped. the full throttle climb was 1100 fpm at 60 knots, unflapped, 1200 fpm at 70 knots, and a cruise climb of 90 knots at maximum continuous power settings gave 900 fpm. I believe that the fitted propeller blades are old technology, and that current developments will significantly improve the rates of climb.

Cruise
In level flight at the maximum cruising power of 95hp the aircraft GPS’s at 138 knots against a current VNE of 152 knots. At 75hp it settles down to 130 knots, and 55hp gives a loiter speed of 118 knots. Elevator forces are light at all times, with no major changes at the various speeds, and with the simple spring trim being very positive and effective.

Fuel consumption at 75hp and 130 knots should be 20 litres per hour according to the manuals, and with the standard 70 litre tank this should give 3 hrs with a half hour reserve - about 400 nm. At around the 120 knots it uses 14 litres per hour which would extend the endurance to 4.5 hours with a half hour reserve - about 540 nm.

Stability
The stick free stability was checked in all axis. In pitch, if the stick is tapped forwards or backwards the nose attitude remains stable in the displaced position, without any tendency to recover. The same applies in the rolling plane. The very slight frictional forces are enough to hold these attitudes. When the rudder is displaced however there is an instant recovery to the straight ahead position. The end result of this is that in level flight the aircraft can be flown hands off, even through some turbulence, without having to correct for attitude changes. Exactly the same applies in turns, even quite steep ones, although of course the trim must then be reset to hold the nose attitude. This means that you can ferret around the cockpit or read the maps and not find the horizon at an unusual position when you look up next.

Control Balance in Turns
The controls are fairly well balanced. The elevators are light and responsive without requiring a great deal of movement. You rest your forearm on your thigh, and fly with wrist movements. The ailerons are slightly heavier, but again very responsive. Because of the longer efficient wings, and the great depth of the ailerons, the application of ailerons does cause some adverse yaw, but which can to be balanced by minor use of the rudder. To a sailplane pilot this is normal, and he would find the Esqual to need very little rudder by comparison. Other pilots that have flown the Esqual have not noticed the need for rudder, as it only becomes obvious at faster roll rates.
 
The co-ordinated roll rate of the Esqual at 100 knots is 2 seconds from +45° to -45°, which is snappy indeed.

Sideslips
These are not a standard manoevre but were checked for the record.
Sideslips with the clean aircraft create a loss of elevator control probably due to the elevators being blanked off by the airflow over the wings. This is evident by a pronounced pitch instability, and is best avoided. However with 30° of flap the aircraft behaves immaculately, with good balance between the ailerons and the rudder. The rate of descent increases dramatically. Sideslip with flaps would not be needed in normal circumstances, as you only have to briefly crank on 45° of flaps to correct the situation. However it could be very useful for a busy forced landing situation, where you make sure that you are overshooting and then wash off the excess height in a sideslip.

Stalls
These were again checked with the GPS against the ASI. Unflapped, the aircraft stalls at 41 knots with a clean recovery and no significant wing drop. With 15° flap it again has a benign stall at 35 knots. With 30° of flap it stalls at 29 knots, but the wing drop was sudden and severe. At 32 knots with 45° of flap the aircraft was becoming unstable and the stall was not followed through.

When an aircraft is stalled with the flaps down, usually the inboard flap section stalls while the outboard aileron section remains flying. As the Esqual flaps take up much of the length of the wing, with only very short and deep ailerons, it appears that the application of 30° of flap causes the outer section to stall as well, which accounts for the wing drop. However to attain the ridiculously low speeds required to initiate the stall, the nose has to be raised so far above the horizon that it would need a determined person to achieve the stall.

These stall speeds are much lower than expected or even claimed by the manufacturer. In case our wind corrections for the GPS were in error, I asked Colin, the Esqual Pilot to calibrate the ASI against the GPS during taxying. They agreed, and an in-flight recheck at low speed confirmed this so the figures stand.
 

Cockpit ventilation
Ventilation is wonderful, with as much air blasted in as you could possibly want, and all in spite of the large greenhouse effect of the cockpit bubble. However if I owned an Esqual, I would overpaint the top of the canopy with white paint, not only for flying, but for leaving the aircraft parked in the sun, to avoid cooking the contents.

Glide Descent
The rate of descent with the prop windmilling is 600 fpm at 60 knots, and 650 fpm at 70 knots. This gives a glide ratio of 10:1. A windmilling prop is a large airbrake, so that in an emergency, if the prop was stopped the claimed 14:1 glide angle should be achieved.
 

Approach and Landing.
On the approach the electric flaps are applied until the indicator on the wing shows 30°. As one would expect the aircraft both balloons upwards, and pitches nose down. A quick retrim, and the approach is very stable with speed being easily controlled. Descent rate at the idle was 1000 to 1100 fpm, and the pronounced nose down attitude gave a panoramic view over the nose. To date we have been approaching at 60 knots, but after these flights it appears that 50-55 knots would be more suitable. The flare was positive and the float was not long. The aircraft settled and stuck without bouncing, and the ground roll was directionally quite stable. At the end of the roll, the toe brakes are lightly used as in normal taxying, for directional control.

All in all it is a very easy aircraft to handle for approaches and landings.

Conclusions.
Many good aircraft kits have been developed in recent years, especially in Europe. However, the Esqual must be a greyhound amongst ultralights, and also amongst many other kit aircraft with much higher powered engines. I was at home in the aircraft from the start, and found it docile and relaxing to both fly and land, with no vices worth worrying about. It’s really quick off the ground, and short on its landings.  My only wish list, apart from some refinements in the kit hardware and instructions, is for the retracting gear version with the new modified wings and hopefully a higher VNE. This should give at least another 15 knots cruise speed, or a greater range at the same speeds due to lower power settings needed.

Bert Flood had kindly offered to rendezvous with me with the Esqual at Corowa, where Malcolm Ferguson is building the second kit. Here I could finish the above evaluation flying. Photo flights were conducted from my 914 turbo Europa, and I asked Colin, to climb to 3000ft and maintain 120 knots to allow me to catch up. Being a bit complacent with the Europa’s performance I let the Esqual climb to near the end of the runway before taking off - but he elected to climb at 100 knots. With his combination of speed and climb rate, at these lower altitudes I just couldn’t catch up to him in time, in the climb. This was rather embarrassing, as I had to ask him to slow down!

Malcolm also flew the Esqual and It is the first time that I have ever seen anyone who just couldn’t stop grinning afterwards. He said that all round it exceeded his wildest dreams. He emailed me afterwards - “For me it was quite exhilarating in that it was the first power aircraft that I have flown that I felt integrated with and not just along for the ride. It just seemed to respond intuitively to to my wishes, very much like a fiberglass sailplane on steroids.”

The aircraft is elegant, and if the wheels were retractable it would be prettier than a Lancair. There is no doubt that it is exceptionally clean in its design, and without that gear dangling beneath, engine for engine it would outperform any Europa. Its speed range is marginally better, although it is biased to the slower speed end. Colin, who flew with me on the evaluation flights, on the way home, trialled an approach and landing at 50 knots in middle of the day thermal turbulence and declared it to be no problem at all, it just reduced the float before touchdown.

Here is an aircraft with 5:1 ratio from stall to VNE. I have not heard of another light aircraft with this speed ratio, yet the carbon version has a ratio of 6:1! Nor have I seen a kit aircraft which compares in the combination of kit quality, simplicity of construction, basic design and general flying performance. The present kit cost as of March 2003 is around $55,000, but keep in mind that it is a quick build kit as standard. Cheaper aircraft kits may be available, but they could take longer to build and there may be hidden costs for these in special tools, benches, upholstery, resins, heaters, glass cloth cutting benches, extra fillers and paints, and many other extras which are standard or not needed for the Esqual. I have recorded $15,000 worth of these extras for building my Europa.

Because the Esqual is built to be light, the Rotax 912S gives all the performance that one could desire, in practical terms. In contrast, say to the Europa, the use of the Rotax 914 in this model of Esqual would be an overkill and easily exceed the present VNE. Hot rodders on the other hand, would revel in the lighter carbon fibre version with the 914, which would start to rival the Lancairs in speed, yet provide docile landings on short strips. However, in practical terms for flying any light glass aircraft, as distinct from the heavy glass commuters, cross country speeds of 120 - 130 knots are the maximum in comfort level in more turbulent conditions. If you want to fly faster, the conditions need to be calmer, either by flying early or late in the day, or by fitting the turbo Rotax to enable you to fly efficiently above it all.

This is my dream - see below!
 Ole  - Barry Wrenford