L-13

PAGE THREE

L-13 LEFT
The 300 hp R-680 Lycoming is a logical replacement for the Franklin 8-cylinder engine that gave boat anchors a bad name and was probably responsible for the military pulling the airplanes from service. That and the helicopters that were just coming on line.

Everything about the airplane is monsterous and overbuilt, and just a little bit different. The control wheels are not mounted on a round column coming out of the instrument panel. Rather, the shaft which disappears into the broad panel is triangualar in shape and rotates on a bushing. Most of the important switches and knobs are arranged across a shelf projecting out of the bottom of the instrument panel, with the rest of the instruments pretty much where you would expect them.

The overall feeling of sitting that high is it gives true meaning to the term "greenhouse" cockpit. Where the pilot sits there is more plexiglass to be seen than airframe. I noticed the seating position was such that there had to be a solid foot between my head and the closest structure, so I looked around and grabbed another cushion, bringing myself to the height the pilot would have had if wearing the seat pack parachute for which the seats were obviously designed. This put me well above the nose and well above Jack, but it also put me in a position that appearedas if it was the height for which all the controls had been designed.

While strapping in, Jack cranked the Lycoming and I suddenly realized how long it had been since I had sat behind a small radial. I had forgotten how different the smaller radials sound when they are being cranked — as opposed to the 450s and up. Lycoming, Contiental and Jacobs radials' starts have this identifiable mechanical sound as the Bendix engages and pulls the engine through. As the mixture caught fire and transformed into power and noise, the R-680 settled into idling lope again so much a part of the small radial mystique. For reasons not clear to me, the tailwheel can be unlocked for full swiveling operation or locked into a steering mode. On this particular airplane, that change must be made by a crewmember while still on the ground by pulling a pin in the tailwheel assembly. I forgot to ask Jack if that was a matter of an actuating mechanism that hadn't been hooked up yet, or if that's the way it was originally designed. Before taxiing out, we made sure the tailwheel was indeed steering and I was delighted to find that it wasn't so much a matter of taxiing the airplane as it was driving. The rudder ratio was exactly right which allowed the plane to follow my feet in a precise and proportional manner. Put a little foot in and we turned a little — put in a lot of foot and we got a lot of turn.

Mags checked and prop exercised, I rolled onto the center-line and slowly brought all 300 horses into the act. As the power came up, the airplane began lumbering forward, requiring practically no input. As soon as the throttle was full in, I leaned on the control yoke asking the tail if it would like to come up into a level attitude. Almost as soon as the tail came up, the airplane levitated off the ground in a nearly level attitude. We hadn't rolled 200 feet. I glanced at the airspeed and it was going through 45 mph, heading rapidly for 60 mph. I wanted to hold 60 mph, which required sucking the nose up to a reasonable steep angle but, looking outside, it was obvious we were going up at a ridiculous climb angle. Since we were covering nearly as much ground going up as forward, I dropped the nose to climb at 70 mph in an effort to vacate the airport in a more reasonable period of time. At the rate we were going, we would have hovered over the runway and become an obstacle to navigation.

Bringing the power back, I let the L-13 climb at about 75 mph which gave something in the neighborhood of 900-1000 fpm. As soon as we were at 2500 feet I pushed over into level flight, bringing the power back and watching the airspeed gradually creep up to 100 mph. Somehow, the airspeed seemed irrelevant. The air-plane speaks to the pilot with a peculiar "voice" that is composed of visual surroundings as much as the way the engine sounds or the controls feel. The greenhouse flight deck has almost a patio feeling — a military patio — since everything was green. As the heat built up with the solar effect, the only items missing were a couple of potted plants and some hanging ferns.

The huge sheets of plexiglass keep the wind out and the heat in, but also serve to establish a visual boundary for the confines which belong to the pilot. There is something about the cockpit that is very mechanical with structural overtones — not unlike sitting on one of those patios or porches made of big, rough hewn beams and looking out over a lake or mountain valley. The cock-pit becomes a stationary vantage point for viewing what appears to be a stationary world, but the plane's mechanical personality comes through as a pleasant undertone adding, not detracting, from the feeling. This is the one and only time I've ever experienced this particular combination and they weren't totally unexpected.

Doing stability tests on this airplane is a little like trying to write your initials on the surface of quicksand. Each disturbance, or each control displacement, is made into a control system that is so lazy, yet willing to comply, that it is a little hard to tell that anything has occurred. If the airplane is pulled 20 mph off trim speed and let go, as the nose comes down, it does so in such a deliberate — yet easy going manner — that it comes back up to original trim speed. The L-13 damped out back at 100 mph without ever overshooting. If pulled into a bank, with the nose held straight ahead with the rudders, the aircraft very positively, but very gradually, rolls out of the bank and establishes a level attitude. As far as control feel and response is concerned, it is far better than the airplane's looks would suggest. The pressures are moderate and the response is better than average, considering the airplane's size, but it's a lot like quicksand. The airplane would just as soon stay level and when you try and push it one way or the other, it does exactly as ordered but is obviously anxious to return back to level.

I tried the first stall straight ahead with no flaps and found both arms wrapped around the control yoke, hugging it to my chest, as we mushed along at 45 mph. The trim, incidentally, is absolultely required. The elevator trim is one of those overhead crank affairs we all hate, but this one is mounted with the pivot axis horizontal rather than vertical. When the crank is moved down, the nose goes down and vice versa. It's a thoroughly logical system — must have been a mistake. The aileron trim is an electric switch on the panel.

I tried the same stall with the flaps about half out and the air-plane suddenly changed character. This time the stall was well under 40 mph, but when it let go, the L-13 started rolling hard right. Out of the corner of my eye I saw Jack's hands come up off his lap. Relaxing back pressure and adding a little power got the airplane flying again. As more flaps were put out, the stall speed didn't come down much but the attitude at which the stall broke definately did. The stall got down to around 35 mph indicated, but the nose wasn't close to the horizon. Also, with a lot of flap out, the instant the nose is started up the airspeed disappeared.

I remembered both Jack and Dan telling me the handbook advised against three-point or full flap landings until the pilot had more time in the airplane. I was beginning to see why.

When we came back into the pattern, I had made up my mind to make the first landing clean with no flaps. I pulled the power off opposite the numbers and rumbled ahead for what seemed like a reasonable time before turning back toward the airport. Almost immediately, I saw I was going to be high — the airplane flat didn't want to come down, not even at 60 mph. As I turned on final it was obvious we were way, way too high. I reached up and toggled in about 30 degrees of flaps. Almost as soon as I touched the flaps, the nose tucked down and the pavement started coming up. I kept trying to remind myself how high off the ground I had been sitting during taxi so I wouldn't catch the main gear. I was definately forwarned, which didn't seem to help. Somehow, even though I started flairing where I though I should, I still managed to drive the mains into the runway like a couple of fence posts. We got a little hop before I pinned it down and did a little dance with my feet to keep the plane straight. This sounds much worse than it really was since it was all happening at a fast walk. I was a little embarrassed, so I thumbed the flaps back in and dropped the hammer to go around and try again.

The second time I stretched it out far enough only a little slip was needed to get us down to the run and this time I was watching really carefully to catch the right height so the gear wouldn't touch prematurely. I was in the process of rounding out when BAM! we hit on the mains again. This time we didn't get any hop at all, as I pinned it immediately and the inboards oleos soaked up any bounce. One of the guys watching from the side lines said it looked like the tail was coming down okay but the airplane never stopped settling. I wasn't watching the airspeed but probably what was happening was, as the nose came up and the speed went down, I should have been increasing the rate of pitch change or maybe bringing in a little power. Jack said either would have helped out, of course, we didn't come to that conclusion until after I'd been embarrassed — again.

After we taxied back to the ramp and I did my best not to fall out of the airplane and hurt myself, I looked at the machine through entirely different eyes. There aren't a whole lot of air-planes that can truly be called unique. In my rather limited experience, most of those that can qualify for the "unique" category also are in the STOL category. It's often at the very bottom of an airplane's speed range that characteristics seem to be exaggerated one way or another. The short amount of time I spent in the airplane convinced me I truly liked the L-13, if only because of its uniqueness.

I'd be willing to bet mastering a full-flap, three-point landing would hone your abilities even sharper than the same number of landings in something usually considered to be much more demanding, such as a Pitts Special or T-6. With the amount of drag generated by those huge flaps, as the airplane would rotate into a three-point position, the speed would disappear instantly and it should be possible to land in no more than four or five times its own length. If there is any wind blowing at all, the way it comes straight down to final touchdown point means, that if the sun is at your six o'clock on final, you'll probably land on your own shadow.

At least one or two other L-13s are currently flying, with several others under restoration, including one over at Tom Crevasse's place which will be using the original Franklin engine. Personally, if given the option, I'd probably re-engine it with a 275 hp GO-480 or maybe an I0-540, to give the airplane its original lines, but with more modern and more powerful horses up front. Either way, this is an interesting, interesting airplane that is also rare enough that not a whole lot of folks are going to have L-13 time in their log books.

Now let's see: assuming I can find my logbook, I can log the L-13 time, next to the Fiesler Storch, which is next to…. BD

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