A Pair of Pazmany's



A "Brace" of Traditional Aluminum "Birds"

Rugged and underrated , the PL-1 and PL-2 provide excellent two place transportation for pilots of any experience level. In a time when the "easy to build", "fantastic plastic" , or "tupperware "kits , as the New Zealanders call them, dominate the market, its refreshing to see a few builders starting from scratch with plans-built aircraft. And the plans and support from this highly regarded designer, an aeronautical engineer, are excellent.

Today, we will fly two Pazmanys , a Grand Champion PL-2 , registered ZK-TLP and built by Trevor L. Parker, and Mike Brenstrum's PL-1, registered ZK-PAZ. Trevor cleared up the confusion between the two types by pointing out the PL-2 is essentially a later version of the PL-1. As a result, the PL-2 is easier to build with its main spar extrusion and perhaps more attractive with its rounder fuselage and cleaner lines. The PL-2 has the wing dihedral doubled to 5 degrees for extra stability and the addition of another flap section for a total of 3 panels. In the comfort department, the 2 inch expansion of the cabin width over the 39 inch PL-2 more attractive.

Construction of the PL series requires "heaps of patience" according to Trevor. He should know, as he invested 6500 man hours over a ten year period to complete his work of art. However, as a guideline, if one doesn't go to the lengths to create a Grand Champion, it is likely that the PL-2 " could be completed in 2500-3500 hours." Trevor advises, " I guess I may have spent too much time on detail , however , the project could be sped up with components from U.S. markets such as : engine mount, landing gear, fuel tanks and canopy." Looking at and flying TLP confirms Trevor's time was well invested as it is undoubtedly a work of art.

The construction manual goes a long way to helping the builder of this all aluminum, aerobatic avion , however, readers should be aware that this type of construction is time intensive compared to many of the currently available kits.







Differences and Similarities

Mike mounted oversized 600 x 6 main tire on the PL-1's tricycle gear making the aircraft even more capable of operating off short, rough fields. On the other hand, Trevor installed three 500 x 5's on TLP to up his cruising speed by reducing drag. Wing tip tanks on both planes hold approximately 25 gallons of fully usable fuel to give a range of 450 miles plus reserves.

Always searching for a snag in perfection, I noted that 42 screws needed to be removed from TLP's upper cowling to complete a good pre-flight inspection. Then they needed to be re-installed. Trevor points out that he built according to the plans in this respect and to his credit, the aerodynamically clean finish probably adds some speed in this high pressure area. However, some form of quick release attachments would be more practical.

Sliding the canopies aft on their rails and taking a giant step up onto the wingwalk allowed access to the reasonably spacious side-by-side seating of the PL-1 and PL-2. We measured the interior width as 37.5 inches at the hips and 39-41 at the shoulders ( slight differences in construction and interior upholstery ). Four point harnesses secured us to the solid seats that were covered with cushions in the PL-1 and sheepskins in the PL-2.

Fuel selection varied slightly, showing the differences that can occur when builders use a combination of judgment and parts selection prerogatives. Mike's rotating valve allowed "off", "left", "right" and Trevor's added a "both" selection.

Oleo pneumatic shock absorbers turned the rutted field into a first class, paved highway. The steerable nosewheel produced excellent, light weight handling and very tight radius turns with its 22.5 degree turn angle - each side.

Of course, both aircraft had distinctive brake systems. PAZ used a "Cherokee style" hand bar mounted on the floor between the seats while TLP had toe brakes and panel mounted "Cessna type" pull knob for parking brakes.

During all ground operations, visibility was excellent and both aircraft control systems were free of static friction in their push-pull tubes.

Power makes a Difference

Lining up for take-off, readers should keep in mind that PAZ is powered by 115 hp Lycoming 0-235 while TLP sports a 150 hp Lycoming 0-320. Mike's brakes could hold the aircraft at full power while Trevor's skidded along the grass under the same conditions. Rotating the nosewheel skyward at 40 knots had the PL-1 breaking ground in 900 and the PL-2 in 700 feet. Climb rates were quite respectable at 800 and 1200 fpm. Mike's PL-1 has a screw jack arrangement that helps overcome the significant right rudder pressure that needed during the 70mph climb. Trevor's neither had, nor needed this trim with the engine offset 1 ½ degrees to the right.

Leveling off at 3000 feet, at 2500 rpm, produced indicated airspeeds of 115 and 148 mph and fuel flows of 6.25-8 U.S. gph. Trevor has confirmed the accuracy of his airspeed indicator with ground runs over a measured course. Other settings have given similarly proven speeds: 2300 rpm - 130 mph and 2700 rpm - 157 mph. Somewhat strangely, each aircraft is placarded for a different "red line" speed (175 and 187 mph)!?

Phugoid pitch testing showed very good stability with each aircraft recovering in 2-2.5 oscillations. Control feel was firm yet responsive, showing a desirable bias towards loading up with airspeed. All in all, a good cross country aircraft. The trim wheel, with indicator, between the seats, provides a slow rate device to keep the pitch loads neutralized. There is no aileron trim in the PL-2, consequently, the pilot is responsible for fuel tank selection to keep the lateral C of G in a balanced mode.

The PL-2 can be approved for aerobatics in N.Z. with limit loads of 6 and -3 "G" at gross weights of 1350 pounds and lower according to Trevor.

In the slow speed handling, the two aircraft were somewhat dissimilar again. The 65% span flaps could be extended at 106mph with the handle between the seats at settings of 10, 28 and 45 degrees. However, due to the strain on the system and the pilot's arm, 80 mph is more reasonable. Mike's PL-1 extension speed was 100 mph and the selection caused a small nose down pitch that was easily compensated for on the control stick. The PL-2 has a rock solid feeling with the extra large flaps down, not to mention a steep descent path. The limited rudder authority does not allow the plane to sideslip all that effectively giving a maximum demonstrated cross wind limit of 18-21 mph. Interestingly, there is a buffeting at higher speeds with these "dive brakes" extended and equally surprising was the fact that Mike's plane stalled at the same speed, with and without flap, namely 35 knots - although I suspect his ASI is under-reading and somewhat unreliable at this speed. Similarly, the high mounting of TLP's pitot on the vertical fin seems to lead to some erratic errors in the 40-60 knot range with the air speed needle racing madly back and forth. Nonetheless, the power off clean stall for the type is published as 55 mph and with full flap and 1500 rpm it's less than 35 mph indicated. Both aircraft exhibited a slight wing drop that was easily arrested with the touch of a rudder. There was no tendency to enter a secondary stall and the aircraft is very difficult to force into a spin. In fact, air force testing found spins were difficult to enter, but once started, if recovery wasn't effected quickly, the turn rate reaches 360 degrees per second and the spin starts to flatten at the third rotation. Recovery from the stabilized flat spin by the 8th rotation is not possible with control input. However, when recovery from the initial autorotation is as simple as releasing some of the back pressure, it is unlikely that pilots will have any trouble - unless they are looking for it.

After cavorting for an hour, proving the easy and accurate maneuverability of the "two" we returned to the circuit to confirm the reasons the Taiwanese Air Force selected this type for their basic trainer. Seventy-five mph on final was adequate, with the flaps allowing us to point the nose down steeply at the threshold. The combination of the low wing's powerful "ground effect" and great oleos (have you read the PAZ's excellent book on gear design ?) made the landings easy "greasers".

Conclusions!?

Considering these airframes are almost the same, there is a significant divergence in performance. These observations are quite interesting because they show not only the effects of dissimilar engines and operating weights, but also, the variations one finds between builders. While its hard to put one's finger on specifics, I far prefer Trevor's Pazmany, and its not just because of the power enhanced performance. The intricate details and attention to minutiae have made the TLP quieter, smoother, roomier, and more comfortable. This is not to say that PAZ is a dog. In fact, it looks very attractive and flies considerably better than the first PL-2 that Ladislao Pazmany introduced me to a couple of years ago. However, if a conclusion can be stated, "you will get out of a project what you put into it." Or as Trevor said, "you've got to maintain the best standard you can right through." For further information on these plans built planes, contact Pazmany Aircraft Corp. , P.O. Box 80051 , San Diego , CA. , 92138 Phone (619) 224-7330 Performance figures are those observed during flight testing by the author, or taken from aircraft operating certificates.

Aircraft Model - Pazmany PL-2 Trevor L. Parker's ZK-TLP

NUMBER OF SEATS two side by side BUILDING TIME 5000+ hours ENGINE TYPE Lycoming 0-320 RATED HORSEPOWER 150 EMPTY WEIGHT 927 pounds GROSS WEIGHT 1465 (1360 during the evaluation flight) PROPELLER Diameter 72", pitch 66" TAKE OFF DISTANCE 700 feet LANDING DISTANCE 1000 feet CRUISE SPEED 130-148 mph TOP SPEED 158 mph VNE 187 mph FUEL CAPACITY 25 U.S. PLANS $425.00 INFORMATION PACK $12.00 for PAZMANY AIRCRAFT



Aircraft Model ~ Mike Brenstrum's PL-1 ZK-PAZ

ENGINE TYPE Lycoming 0-235 RATED HORSEPOWER 115 EMPTY WEIGHT 927 pounds GROSS WEIGHT 1454 pounds PROPELLER Diameter 69", pitch 54" TAKE OFF DISTANCE 700 feet LANDING DISTANCE 1000 feet CRUISE SPEED 115 mph TOP SPEED 158 mph VNE 175 mph FUEL CAPACITY 22 U.S.

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