Experimenter

May 2013

Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.

Issue link: http://experimenter.epubxp.com/i/126719

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Ancient Words At last! A Simple Pazmany! very little racket, but the tone of the exhaust made me feel as if I were tailgating a Beetle. By Budd Davisson It's hard to believe that I wrote the following words 40 years ago for Air Progress in June 1973. I had just flown the prototype Pazmany PL-4A, but not for a second did I think that four decades later I'd still be talking about it. This is a good little airplane and a perfect scratchbuilt light-sport aircraft. Besides being relatively simple, it uses a belt-reduced VW, so it can be built economically. Hey, nothing wrong with a good airplane regardless of the age. As I sat at the end of the runway, I panicked for a second when I couldn't find the mag switch. Then I remembered that with a VW it's a go or no-go situation. If the engine is running, the ignition is okay; if it isn't running, I shouldn't go flying. Seems simple enough. The test pilot had warned me that the PL-4 was fairly sensitive in the pitch mode, so I should be careful bringing the tail up. It's a good thing he warned me. I gave it full power, which means the engine is cranking nearly 4,000 rpm and sounds as if you're doing 200 mph. With about 50 horses available, the acceleration doesn't make you swallow your gum, but when we were clipping along and I started to raise the tail, I got my first surprise of the flight. It is sensitive in pitch; because the tail jumped up, and I had to bring the stick back quickly to keep from plowing pave¬ment. It was easily corrected, but it's something to watch for, at any rate. A 300- to 400-fpm climb isn't going to wow many aerobatic or warbird types (Editor's Note from 2013: This was with a stock 40-hp VW. A later, bigger VW would make a rocket ship out of it), but I'd like to see their airplanes do as well with this much power. It takes a little while to get out of the pattern at 60 mph, but I needed the time to get a feel for the controls anyway. When I first left the ground and started fighting gusts, I found that either my hand had sud¬denly turned to ham or the PL-4 had very sensitive controls. At altitude, I investigated the con¬trols more thoroughly. After batting it around a little, I found the problem wasn't one of light controls; it was the fact that you didn't have to move them very far, and they didn't have the conventional amount of friction. Your feet become very useful in turns, because the long wing and its unusually high aspect ratio of 8:1 generate lots of adverse yaw that even differential ailerons couldn't completely correct. It's actually a very easy airplane to coordinate, but you have to think about it first. To check stability, I'd bash the stick forward or to one side and release it. The airplane would jump and then return to level flight. Many homebuilts don't have this stability, especially in pitch. It's really wild to be bouncing along, trueing about 80 mph and looking at a tach that reads 3,000 rpm. The big 74-inch prop made With the spook tales about T-tails in my mind, I set up for stalls and came in very gently with the back pressure. Down around 45 to 50 mph, it gave a sharp jump and the nose started down. The initial sharpness surprised me a little, and I didn't waste any time recovering. The next time, I decided to hold it back to see what would happen. Again it broke rather sharply, with the left wing dropping slightly. But almost as soon as it broke, it stabilized in a mush. What had appeared at first to be a bad stall was actually just a sharp break; once stalled, it is thoroughly docile and easily controlled. The most interesting part of any first flight is the landing, and this one was all the more interesting since some klutz in a 182 turned inside me and cut me out on final. Against my better judgment, I slowed down and came in behind him, holding 80 in¬dicated, which was actually 60 true. I remembered the sharpish-breaking stall and flew it right down to the ground before bringing the nose up. Then, just as I was about to touch, I caught either a gust or the Cessna's wake and started drifting sideways at a speed I didn't think I could correct for without digging in a wingtip. I hit the power to go around, correcting for the drift as I did. I touched the runway for a second before taking off again and saw immediately that I could have probably gone ahead and land¬ed, because crossed controls did stop the drift. I went around anyway, fi¬guring I'd made one mistake already—no reason to compound it. The next several landings were completely uneventful, if you can call consistently landing two feet in the air uneventful. I just couldn't seem to judge my height, and the airplane would quit flying before I could find the ground. At least I proved that the PL-4 will take care of itself. My only real complaint with the airplane was that its quick controls might scare the devil out of the builder on his first flight. Often a man who has taken the time to build an airplane hasn't kept up his piloting skills and is not as sharp as he should be when he test-hops his airplane. Pazmany realizes this and is now working on a way of increasing con¬trol feel. (Editor's Note: This was rectified.) He's also planning to experi¬ment with all the various VW modifi¬cations, the Kiekhaefer engine, and the old 65-hp Lycoming and Conti¬nental standbys. He expects perform¬ance to jump when he gets a true 65 hp out front. It's an unfortunate part of sport aviation that people are often attract¬ed to airplanes that are beyond their abilities as pilots or builders, or both. The Pazmany PL-4 is a fine solution to the problem. It's inexpensive, easy to build, and it can safely be flown by anyone who can handle a Cub. The PL-4 is the kind of airplane people should be building, but aren't. EAA Experimenter 17

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