Slick Aircraft Overview
Introduction by Glen Dell
The “prototype" Slick 360 was built based on the Laser and Extra 230. It had the basic layout of the Laser (the same wing profile, elevator and rudder) and the control system of the Extra. The composite wing was stressed to +/- ten “g’s” but retained most of the steel tube construction of the Laser/Extra. The huge success of the plane and subsequent orders made us look for further ways to improve and develop the Slick.
The roll rate on the first Slick had been adequate. While wanting to avoid roll rates in excess of 360/400 degrees a second however, it had to be acknowledged that a slightly higher rate would have been advantageous. The aileron size was increased by some 50% but retained the spar at 22.5%. The increased size however was not compensated sufficiently by the aerodynamic balancing of the spade and the spar was moved further back to 25%.
A comprehensive flutter analysis was undertaken, both statically and whilst airborne. This showed very little possibility of flutter at speeds below 500 knots. Since this speed was considerably above the Slick’s VNE, we decreased the amount of balance weight in the ailerons to a little less than 50%. This is approximately the same percentage of mass balance as that used in the Extra 300. This provided the aircraft with a roll rate of 360 per second while maintaining smooth and light control forces. The wing was also modified to take more fuel for cross country flights and future aircraft may have facility for a small smoke tank mounted in the left wing just behind the main spar. In addition, simple plastic pipes were manufactured into the wing to allow for any electrical “goods” that the owner might wish to install at the wing tips (strobe lights, camera etc.).
The undercarriage (from Grove USA) was slightly changed in a number of respects. The gear was gun drilled to allow for the brake lines and slightly reducing drag. The height of the gear was increased to allow for a two blade propeller choice (e.g. the MT-15). The tail wheel was installed in such a manner that the fuselage angle was maintained keeping the same good forward visibility of the prototype. The spats, which cover the brake calipers as well as most of the wheel, are made of a composite mix which gives maximum strength for minimum weight. The gear itself is well supported where it joins the fuselage by carbon fiber longerons and the doubled Carbon Fiber / Kevlar mix in the cockpit area.
The biggest change to the production Slick from the prototype is the all composite fuselage and tailplane. There were various reasons for choosing to build the Slick as a “fully composite” aircraft. Amongst these reasons was that the internal space is greatly increased since there is obviously no internal tubular frame. This increases the useable width of the cockpit area by some eight inches (nearly twenty centimeters) and will allow the development of a two seater Slick with little modification required to the basic fuselage. Pilots who fit into the somewhat “larger” category can now quite comfortably fit into a four cylinder aerobatic aircraft – not a common occurrence. Naturally the aircraft can be manufactured with far cleaner lines and the overall finish is superb.
The tail section of the aircraft is also constructed of a variety of composite materials. This does away with the necessity for flying wires which add drag, are very expensive and can take a few months to manufacture to specification. The aerodynamically profiled control surfaces are also somewhat more efficient. Unlike the Giles or Cap222 the Slick has been designed from the outset using Carbon Fiber longerons and ribs. Although this adds some weight the overall strength of the fuselage is increased greatly. During testing of the first production fuselage the horizontal stabilizer and engine mount were fixed to a surface and then 14500 pounds of upward pressure applied to the main spar. At no time was any deformation apparent and the test was concluded at this point as there was no test equipment available strong enough to apply a greater force to the fuselage. The entire rear section of the fuselage has been designed to allow for great aerobatic forces and to avoid the tail wheel problems that have plagued some full composite aircraft. The elevator has a horn in which the mass balance is situated and this of course supplies aerodynamic balancing as well. In addition the right hand side of the elevator has a trim tab, the control of which is on the right hand side of the cockpit.
The rudder is similar to that of many top aerobatic aircraft and has an aerodynamic balancing horn totaling some 15% of total rudder area. While most of the fuselage is manufactured of Carbon the leading edge of the vertical stabilizer is BD Fiber Glass allowing for radio transmission from the VHF aerial which is situated there.
The first production Slick has been fitted with a forward opening canopy. This idea will be abandoned on future aircraft in order to save the weight of the mechanism which opens / closes / locks it.
The cockpit interior is substantially larger than a Pitts or One Design type aircraft because there is no tubular steel structure. The seat is reclined allowing for more tolerance to “g” forces and has an insert to allow for different size pilots. These inserts would be made to fit a specific owner and his or her parachute. The rudder pedals are adjustable allowing a six foot four pilot comfortable seating with a parachute. Headroom is ample and a five foot ten inch tall pilot requires some cushions, in addition to his parachute, to get to the correct seating height position if flying with a “tall pilot” seat insert.
Flying controls – stick, rudders, throttle, trim and tail wheel lock are all within easy and comfortable reach of the pilot. The radio and transponder are situated on the left hand side of the instrument panel as well as airspeed indicator and altimeter. The centre of the instrument panel has space for a sequence card which will temporarily cover the fuel gauges. On the right are the engine instruments and the starter key.
The seat is covered by a neat light weight leather insert which prevents long term damage to the paint work there.
The canopy is of the highest quality free blown material allowing undistorted visibility throughout. Because of the midwing configuration and associated difficulty with visibility of the box, a window has been incorporated into the lower fuselage below the wing.
Hooker harnesses are used throughout with one ratchet on the right lap strap allowing the pilot to ensure ideal security with little effort.
A baggage area is located behind the pilots head in the turtle deck area. This may be removable but the overall weight is minimal.
The sideways opening canopy allows easy access. It is fitted with a canopy ejection system on the right hinges and the normal lock/ unlocks arrangement on the left.
The engine is the AEIO 360 Lycoming. Early production models had the angle valve version modified by AeroSport Power in Canada. The latest Slick (009) has the Barrett Precision Engines modified parallel valve engine. This has about 10% less power but about 15% less weight than the angle valve version and is probably the finest four cylinder aerobatic engine available today. Features are too many to mention here but include cold air induction. The greatest advantage we have encountered to date with this system is the shape of the sump. The sump is far deeper and holds more oil preventing the loss of oil pressure during maneuvers so often associated with four cylinder engines.
The engine has one magneto and an electronic ignition system. The electronic ignition allows for ideal timing over a far higher rpm, altitude, temperature etc. range that would be possible with a magneto. The engine is equipped with a light weight starter and alternator.
The exhaust is custom manufactured in SA. It is a light weight four into one stainless steel system. The exhaust helps to increase the performance of the engine while at the same time producing a smooth (no four cylinder “popping”) sound. The oil breather pipe which normally runs down the fuselage and drops black oil over the hangar floor has been changed to vent into the exhaust system. This saves the weight of pipe, prevents oil “spills” and provides a slight negative pressure in the sump thus preventing minor engine oil seepage.
Depending upon requirement, propeller choice may include the MT two or three blade propellers. Performance of these are similar but pilot requirement might dictate a specific type for air display type flying, noise or just because of looks! There is no reason why any good quality aerobatic propeller cannot be used. Slight weight differences affecting the CofG can easily be compensated for by altering battery location.
The Paint Scheme
The aircrafts price includes a paint finish in one colour. Any scheme can be provided, the complexity of which will incur some cost.