The North American version of a Polish trainer is likely to find favour in the USA.
John Wiley/Atlanta
Polish manufacturer PZL of Warsaw and US company Cadmus, of Northfield, Illinois, have teamed up to build, certificate and market the Koliber II light-trainer aircraft. On the surface, this sounds like a simple story, but the reality is more complicated.
While the Koliber II is newly certificated in the USA, it is not a completely new design, nor is this the first time that the basic design has passed US certification. The Koliber II, also known as the PZL-150A, is not the same aircraft as the PZL-150 sold in Europe. PZL did not originate the Koliber design, and it was not the aircraft that first piqued the interest of Cadmus chief executive Phil Coleman. Finally, Coleman's initial exposures to PZL aircraft did not come in Poland or the USA, but in China.
The original design, named the MS880 Rallye, was owned by French company Morane Saulnier, and the aircraft was first flown in June 1959, powered by a 67kW (90hp) Continental C90 engine. By 1960, more than 514 orders had been logged and, by 1963, Rallyes were being flown in 38 countries. The Rallye was certificated in the USA in 1961 and again in 1968, when it was modified.
The design went to Poland in 1977 when PZL acquired a licence to build the Rallye. Renamed the PZL-110 Koliber, or Hummingbird, the engine was changed to the 93kW Franklin with a two- blade, ground-adjustable propeller. The aircraft, with a maximum take-off weight of 850kg was basically the same as the Rallye 100ST. Polish certification came in August 1979.
In 1986, Coleman, who was then working as a representative for Hong Kong Aircraft Engineering, visited an aviation trade show in China, where he noticed a sleek little turboprop trainer aircraft, called the PZL-130 Orlik (Eagle). This, in turn, led him to discover the PZL-110 Koliber, and he believed that such a simple trainer would sell well in the USA.
David Coleman, son of the Cadmus president, says that neither PZL nor Cadmus anticipated the complexities of US Federal Aviation Regulations Part 23 certification, or the difficulties which arose because no training aircraft had been certificated in years. According to Coleman, there were "...no resident experts on how to go about certifying the aircraft and we had to employ former FAA [US Federal Aviation Administration] personnel to assist in the project. Actually, we were quite surprised it only took two years to certify the Koliber." Changes ordered by the FAA included such things as the dual electric trim, and flight-manual revisions.
'AMERICANISED' KOLIBER II
Coleman says that the PZL Koliber II (PZL-150A) is now "60% Americanised" with its 24V electrical system, avionics, engine and changes specified by the FAA. Thus, it is a different aircraft from the PZL-150 sold in Europe.
The 12.6m2 Koliber II wing has a 7o dihedral. A set of aerodynamically, actuated slats, cover the entire leading edge span. The slats are coupled to prevent individual actuation and are dampened to prevent slamming in and out. The slats are deployed aerodynamically in a speed range from 60-62kt (111-114km/h) according to gross weight.
The current engine is a Lycoming 0-320-E2A rated at 112kW. Three fixed- pitch Sensinich propellers are available, with blade angles variable through 18.4o, 17.8o and 17.2o. When using the intermediate propeller, a limitation of 2,700rpm must be observed when flying faster than 200kt. A total of 177litres (39gal) of fuel is carried in the wings, of which 160litres is useable. Along with cockpit gauges, fuel can be visually checked on the preflight inspection. A planned modification will add a sight port between the current fill port and the wing root to make this easier.
Controls are connected via rods. There are no cables. The landing gear is all trailing-link, and there is no nose-wheel - steering is with differential braking.
The aircraft is certificated for day, night, instrument flight rules and visual-flight rules; but it is prohibited from flight in known icing conditions. Speeds are posted for take-off at 54kt with zero flaps. Vx is 61kt, Vy is 79kt and turbulent air penetration at 97kt. Approach speed is 65kt. At 4,127kg, take-off at 15oC, sea level, over a 50ft (15m) obstacle is 1,300ft. At 2,000ft elevation, take-off distance increases to 1,580ft.
Rate of climb at sea level in standard conditions shows an initial figure of 670ft/min (3.5m/s) and 485ft/min at 2,000ft elevation. Cruise performance is 118kt at 4,000ft and 2,600rpm and 111kt at 65% power. Stalls with zero flaps occur at 52kt, and at 49kt with full flaps.
With a maximum gross weight of 850kg, useful payload is put at 305kg. Cost has recently been reduced to an introductory price of $79,500, equipped with the Lycoming engine.
The 150A is being targeted at US flight schools - which have not had a new trainer available for years. Coleman says: "We feel flight schools need new aircraft for training and the 150A is ideal for both basic training and for initial instrument training. With a 106kt cruise, this is not a cross-country, aircraft, but that is not our market".
He notes that the main selling points are stable, docile, handling and a canopy, which can be opened in flight. The canopy slides back and is attached along a rail, which extends down the top of the fuselage. With the canopy opened less than 100mm, the Koliber can be flown up to 260kt, but, opened more than 100mm, speed is limited to 170kt.
Coleman also notes that the Koliber is "an extremely safe aircraft", with no recorded fatalities since 1982. The aeroplane is stall resistant, but Coleman admits that, once in a spin, the aircraft "...spins up quickly". Spin recovery is standard.
"We don't expect to sell hundreds of Kolibers," says Coleman, "but we do expect to penetrate the market with constant low volume sales."
PRE-FLIGHT CHECK
My short flight in the Koliber II took place from a suburban field in Atlanta, Georgia. McCollum Field is about 45km (25nm) northwest of Atlanta and sports a large gravel mine near the end of the runway. This pit, plus the adjacent terrain, creates a swirling cross wind at the end of the runway, an excellent challenge for a trainer.
The walk around revealed, the same attention to detail found in the only other PZL aircraft I have flown, the Wilga. It is utilitarian and functional. All three landing gears are training-link, to soften student landing. The large Fowler flaps span a major portion of the wing training edge. A check of the elevator revealed the dual trim actuators.
Once satisfied with the pre-flight, I climbed the wing and stepped down into the cockpit. Seated and fastened in, Coleman and I still had enough room to reach around the cockpit and not bump shoulders. The cockpit appeared neat and simple. Switch location was good.
For control, the Koliber II has sticks rather than columns. A second throttle is placed to the left, so that pilots can fly with their right hand and control power with their left, just like the "fighter guys". Other controls, such as mixture, carburator heat and flaps, remain in the centre, however, which means that, once in the pattern, the pilot will be forced to do a hand dance or revert to the left hand for control and the right hand for power and flaps.
Engine starting was simple, but, taxiing out of the chocks, I was able to pivot the aircraft almost 200o by misapplication of the brakes. A little forward speed helps manoeuvre the Koliber on to the ramp. I later adjusted to the differential braking with little additional problem.
Normal flap position for take-off is up, although flaps are recommended for short-field operations. Our first take-off was with no flaps. Acceleration was standard and I used a moderate pull to rotate the Koliber at 50kt. Stick force was good with ailerons slightly lighter than elevator. Initial rate of climb was approximately 800ft/min. In the airwork area, stalls were hard to come by. At slow speed, the Koliber mushed toward earth and only later in the flight, when I pulled the nose up sharply, was I able to get a defined stall. At slow speed, one can literally pull the slats out and push them back in with stick movement. Slat deployment and retraction does not change handling noticeably.
The view from the Koliber was very good, a fact which helped immensely when returning to the pattern at McCollum. A seemingly new tower operator contributed to some confusion in the landing pattern and the Koliber's excellent visibility allowed us to keep the other aircraft in sight as some broke out of the pattern.
We made three touch-and-go landings, two with full flaps and one with no flaps. Coleman made an astute comment, saying: "This aircraft flies like a cross between a tail dragger and one with tricycle gear. You have the advantage of tricycle gear, but you have to continue flying the aircraft all the way to the ramp, just like a tail dragger." This was quite true, as the Koliber wanted to skip about the runway in the gusty winds and I had to continue control inputs throughout the touchdown and roll out.
Our full-flap landings were made at 105kt. Another point is that the Koliber will float if airspeed is excessive, a factor which will drill into students the necessity to hold target speeds for landing.
The no-flap landing produced little difference in handling although the flare required a stronger and longer pull on the stick. With the wind continuing to roll out of the gravel pitch, active application of aileron and rudder was needed to keep the Koliber on a correct path at 110kt. Because the Koliber has rods instead of cables, there is an immediate response from control input.
Since it was a warm day, we opened the canopy fully. One learns quickly when pointing out traffic that it is best to keep one's hand inside the cockpit rather than thoughtlessly out in the airstream. Noise did not increase appreciably and handling did not change noticeably.
For the final landing, we chose a 90kt short-field approach. Coleman stopped the Koliber in less than 500ft without harsh braking. No doubt, stamping hard on the brakes would have reduced the landing distance considerably.
CONCLUSION
The Koliber II is a simple trainer with docile handling characteristics. The stick will appeal to many students and the trailing-link gear will soften landings. The leading edge slats and trailing edge Fowler flaps will allow students to work on true short take-offs and landings. Visibility is very good, another valuable factor for an airplane that will spend considerable time in the pattern.
Source: Flight International
