Test and Photos by Budd Davisson, Air Progress, October 1973

When I called Leo Loudenslager in mid-1972, he didn't know me and I didn't him. He was just the guy with the monoplane who was going up against the Pitts gaggle single handidly. On that first call, he said, "sure, you can fly it, but can you wait until I fly the nationals?" It would be his second contest. From that point on, we became friends and I consider him to be one of those rare world class people who direct their genius in a given way and, in so doing, leave their mark on the world. In the aerobatic arena, you have only to say the word "Leo" and everyone knows who you mean. We miss you Leo. Alot!

Also, in re-reading what I wrote, some 28 years ago, it sounds incredibly naive. But that's what we were in those days; naive and excited to be doing what we were doing. Most of us are still excited. BD

Before Leo Made it a Laser, it was a Stephens

People in the know speak of the Stephens Akro in hushed and slightly fearful tones. It looms on the aerobatic horizon like the stranger come to town to teach the Pitts boys a thing or two about aerobatics. Is it a Pitts killer and is Leo Loudenslager the man to pull the trigger?

Let's make it clear right now that I'm not the guy to answer that question. My name isn't Soucy, Herendeen, Hillard or Poberezny. Around the airport, I'm known as "Fumbles," and after an exciting week when I flew the Stephens Akro and the 180-hp symmetrical Pitts, back to. back, I've decided that I wouldn't want to be in the ring with any of the big guys in either airplane.

America has finally popped out on top of the international aerobatic pyramid for two reasons: because of our pilots and because Curtis Pitts builds airplanes for us instead of them. If we didn't have the Pitts, we probably wouldn't have the Nestorov Trophy either. Our team is a happy combination of superpilots flying superairplanes. But nothing stands still in competition, and since it's hard to build better men, improvement will come in the form of better machines. And if Clayton Stephens has anything to do with it, one of the machines will be his Stephens Akro.

According to the legends filtering out of the San Fernando basin, the Akro exists because the late Margaret Ritchie wanted to beat Mary Gaffaney. Actually, Mrs. Ritchie wanted to beat everybody, but her clipped-wing, 150-hp Taylorcraft just couldn't cut the mustard. Even with its big engine and symmetrical airfoil, it rolled too slowly and had to pull around too much fabric and tubing. Clayton Stephens, an aeronautical engineer trying to add spice to his aerospace career, came to her aid with his slide rule and drafting machine.

Since Stephens wasn't, and isn't, an aerobatic pilot, he had to do the entire project with numbers and formulas. He had no prejudices or preconceived ideas. He looked at the maneuvers, studied the airplanes, and designed an airplane that broke the

At that point in time, American aerobatic tradition dictated using two wings as the basis for any aerobatic design. The Akro, however, is a monoplane.

Basically, the resulting design resembled an underdeveloped Formula One racer. As a matter of fact, part of the fuselage layout is supposed to have been inspired by Art Scholl's old Miss San Bernardino. In racing, the midwing layout was conventional, but in aerobatics, it was downright radical. If throwing away one wing didn't make the machine unique in the world of aerobatics, his airfoil did-it wasn't symmetrical! The modern development of superaerobatic airplanes requires that more and more attention be paid to outside maneuvers. This means the wing should lift equally both ways, but the Stephens' doesn't. The airfoil is an old favorite, the 23012. I hate people who banter airfoil numbers around, but this time it's important. The 23000 series airfoils don't lift the same upside down as right side up, so Stephens climbed out on a limb when it came to outside, or negative G, maneuvers.

The construction is absolutely conventional and straightforward. The wing is plywood covered-with a 24-foot, 7-ply railroad tie running wing-tip to wingtip. The fuselage is miles of chrome moly and fabric. At first glance, the construction looks deceptively simple, but it's not. Laminating the spar requires that the builder construct a clamping table, 24 feet long and perfectly true. It's not difficult, but it's certainly not as simple as whittling out Pitts ribs and spars and letting the flying wires handle the problem of strength. Since it's a cantilever wing, you'd better be right the first time you build it, because there's no way to rig out any basement booboos once you're finished. Any twist in the wing is going to make the airplane fly like a cork-screw.

Although there are at least six Stephens flying, Leo Loudenslager's is by far the most interesting and most advanced. Leo is, by his own admission, a total airplane freak. "I guess you'd have to say somebody is crazy to spend five years building and rebuilding an airplane," he grins. "I could have been much farther along if I'd built a proven machine, like the Pitts, but the second I saw the Akro, I knew this was it for me."

Since he first started building his airplane, Leo has functioned as Clayton Stephen's eyes and hands. He has tested and modified the airplane, advising Stephens how the changes affected his maneuvers, so plans could be changed accordingly.

Walking around the airplane, you are aware that this is the embodiment of "form following function." The lines are so angular as to be harsh and the bubble cockpit really is a bubble, perched atop the skinny fuselage as if it were an afterthought. The horizontal tail has Buck-Rogers tip-plates added only recently to increase the elevator effectiveness without increasing the area.

The things trailing back from the wingtips are unnamed, but will probably be known eventually as LLLs (Loudenslager Line Layers). He can squint out at those weird looking little mobiles and tell when he's exactly vertical or at 45 degrees. Contests are won and lost on angles, so it probably won't be long before everything from Citabrias to Pitts start sprouting these things.

The first part of my checkout was aimed at getting me in the cockpit. I didn't want to walk on the wing, so I had to stand tiptoe on the step and stretch my other leg into the cockpit. Once I was inside, Leo explained things and mentioned that the cockpit was tailored for him, so I might find things not exactly where I wanted them. I saw what he meant when I tried the brakes. Because of a previous modification that lengthened the rudder pedals, the brakes were right up against the bottom of the tank. I was wearing a, pair of square-toed boots and I really had trouble with the pedals.

I must've scared the pants off Leo when I taxied to the far end of the runway and then disappeared for 10 minutes. On the way down the taxi-way, that big 200-hp Lycoming dragged me along at 20 mph, even at idle. I'd try for the brakes, but the tailwheel was so sensitive that giant stabs at the brakes caused me to weave all over the place. Figuring fear was the better part of valor, I pulled the mixture and coasted to the end of the taxiway. I yanked my boots off, sat them on the wing and waited. Pretty soon Leo came around the bend; he was much calmer than I would have been in the same situation. With a couple flips of the prop, I was on my way again in my stocking feet.

Visibility during runup and while checking for traffic is fantastic. It was as though I were sitting on a bar stool on top of the wing. The cockpit isn't large enough to do a lot of romping around in, but it is far from tight, and I didn't even notice the main spar passing over my legs. A guy with longer legs or more girth might find the spar hitting him just below the knees, though.

Leo had said not to worry about torque on takeoff, so I rammed the power in fairly rapidly. He was right. It tore down the white stripe with very little help from me. My feet didn't even get into the act, and I had barely gotten the tail off the ground when those long wings reached out and hoisted me up off the runway. The acceleration was fast, lightning fast, compared to most lightplanes, but it didn't have the heart-stopping surge of a Pitts. That could be because I was up and away in the Stephens at something like 65 to 70 mph, while a Pitts usually stays on the runway longer than that.

And was I ever going up! At 100 to 110 mph indicated, the runway and surrounding hills dropped away so fast it was almost frightening. On later takeoffs, I tried to hold 90 mph and time the climbs. They came out around 2,700 to 2,800 fpm, for at least a 30- to 40-degree angle. People on the ground said they could easily see the tops of the wings as I climbed---it climbs even faster than a Pitts.

Except for the climbout, so far I felt as if I were strapped into a wildly hopped-up Citabria. It had been extremely stable and had an unusually familiar feeling. There was no strange-airplane syndrome, where everything is unfamiliar and hard to get used to. I felt as though I'd had 1,000 hours in it from the beginning.

In cruise, it hops along at around 140 mph indicated (150 mph true) and handles like I'd hoped it would. There isn't anything among normal airplanes that favorably compares with it in straight-and-level flight, except possibly a Swift. The control pressures are light, lighter than a Pitts when fully deflected, but the stick travel is much greater. A little aileron calls for a little stick, and a lot of aileron demands a lot of stick. It feels as if the stick and the control surfaces are directly connected, without linkage, because the slightest movement of the stick provokes an instantaneous reaction. Since the wing is nothing more than an airfoiled slab with little or no dihedral, the airplane has no particular reason to stay in level flight, so it gimbals effortlessly about its center of gravity.

My total time in level flight consisted of two tight clearing turns in either direction, before I tucked the stick to one side and watched the horizon curl across the top of the canopy in a sensuous roll. From that point on, I must have looked like an aerial otter; I'd flop through a frantic series of maneuvers, stop for a second, look quickly around for traffic, then start writhing around the sky again.

In normal aerobatics, the Stephens Akro is a damned boring airplane. Loops, rolls and the mundane normal maneuvers happen with the precision of a push-button machine. Pull, and you loop. Stick to one side, and you roll. Simple as that. Leo has a grease pencil X on the windshield that you can fly like a gunsight, and to keep that exactly where you want it demands only a little more technique. It makes sport aerobatics almost too easy.

The second I pointed the nose straight up, I could see that the Stephens was going to be a mean airplane to beat in competition. It seemed to go uphill forever, and vertical rolls were a simple matter of putting one of the LLL attitude indicators on the horizon and slamming the aileron in. A little rudder and stick action was all that was needed to make the wingtips rip around the horizon. At first I was banging the stick hard against one leg, but I was whizzing around so fast that I would pass my starting point, do a 1'/4 vertical and end up with too much speed. I found I could casually pull up from 180 mph and do a leisurely roll and still have plenty of speed to fly away inverted. From around 200 mph, I was trying to do vertical four-points, not one of my best maneuvers, and I was amazed at how easy it was to come banging to a halt every 90 degrees, then start rolling just as quickly, heading for the next point. Boy, does this thing do vertical rolls!

The really surprising thing about its vertical performance is that it doesn't pick up speed too fast going down-hill. I guess gravity works the same for all airplanes, biplanes or other-wise, until aerodynamic drag raises its fuzzy head and .slows down the bi-planes as they go past 100-120 mph.

On my first inverted recovery out of a hammerhead, I banged the throttle a little too hard, and the added slipstream over the tail made it so effective that it felt as if the airplane stood still while the tail moved down. That was probably one of the squarest outside corners I've ever made.

I don't know who said semi-symmetrical wings aren't supposed to work inverted, but he was wrong because the Stephens doesn't know right side up from upside down. The nose attitude inverted is as flat as a fritter, and I had to really work to make inverted turns without gaining attitude.

As far as that goes, I gained altitude no matter what I did. I tried six or seven outside loops before I got one to come out at the same altitude. I kept gaining 300 to 500 feet in each. The controls are so incredibly effective at slow speeds that I could do half-outside, half-inside square loops with half rolls on each leg, and still not be going much over cruise speed on the way down. I tried to push up into a full vertical roll from inverted, but the top of my head started to come off so I chickened out.

The snap rolls are blinding, blurring, whirling affairs that squeak to. a halt in an instant. Basically, they are simple: yank, stomp and hold onto your hat. I was snapping going up, down, across, everyway.

The notes that come with the Stephens plans say it rolls at 180 degrees per second, which is exactly the same as a symmetrical "round-wing" Pitts, but I find that figure hard to believe. The Pitts seems faster than the Stephens. Of course, once you're rolling faster than about 150 degrees a second (most aircraft are in the 60- to 90-degree range), everything is a blur, anyway.

Even though it was unintentional, I did a wild stall series in the Stephens: straight up, straight down, inside and outside, as I fell out of muffed maneuvers. Whenever it stalled, I felt as if I were standing on a four-foot square of plywood balanced on a bowling ball. When the wing unloaded, I never knew for sure in which direction it was going to go. It has a sharp break, but then mushes with one wing dropping. Kicked into a spin, it goes around like a Fourth of July pinwheel-faster, it seems, than a Pitts and harder to stop.

On the way down, I timed the rate of descent at approach speed (80 mph) and found it to be around 800 to 900 fpm, about like a Cherokee. What I couldn't measure, and didn't even notice until I got into the pattern, was the glide ratio. The airplane is so clean that it goes and goes. I shot three or four landings, making each pattern bigger and bigger, and even with no power, I ended up slipping to get the thing down. That's an area where the Pitts definitely loses out. A Pitts comes down like a manhole cover with a drag chute.

Landings are absolutely beautiful, whether on the mains or in a three-point. The gear is exactly as stiff as it should be, and the tailwheel and rudder are effective enough to control, but not so sensitive that they get you in trouble. Since it stalls at around 50 mph, you can be on the ground at a near walk, with a clear view in front of you at all times. It's almost like landing a Cessna 150.

On my last landing, I still doubted my ability to get the brakes on without damaging my bunions, so I cut the mixture as soon as I touched and rolled to a halt. As I pulled the canopy open, Leo trotted up grinning. All I could say was "Doesn't this thing do anything wrong?"

You're probably begging me now to say, "Yes, it's better than a Pitts," or "No, the Pitts is still king." But I'm not going to say either, and I'm not copping out. The Stephens and the Pitts each has its own character and maneuvers at which it excels. In the Pitts, for instance, it takes some work to figure out how to hammerhead properly, but once you get the hang of it, it pivots as it you've driven a nail through the rudder post. The Stephens won't pivot that way. It's an easier airplane for the new pilot (me) to control because the control ratios are longer, requiring more input per maneuver, which makes it less twitchy looking. They are two different airplanes, so they are bound to fly differently.

When all is said and done, it comes back down the pilot. There aren't 20 pilots in the U.S. who would be able to capitalize on the difference between the two airplanes-they are so closely matched. I think, though, that the two would make pilots develop different styles; the Pitts encourages a quick, zippy sequence, while the Stephens evokes a smooth and ballet-like performance. But, either airplane is capable of doing everything the other can, and either will eat the European machines alive. Put a champion in either airplane and he would still be a champion.