Pirep by Budd Davisson: as appeared in Sport Aerobatics. Photos by Dave Gustafson and Budd Davisson
Another Kick-Butt Biplane From Curtis (via Aviat)
Pitts Special! Now there's a name that has more than its share of mental images attached to it. More than any other single airplane, it has been the omnipresent American aerobatic machine for generations. In fact, it seems impossible that it has been over half a century since the first of the little pug-nosed acrobugs took to the air with 55 wheezing horses up front. A lot of avgas has gone under the bridge since then, and the Pitts clan has grown and prospered until the models and variations take a score card to keep track of.
Equally as difficult to believe is that 2001 marks exactly 30 years since the first certificated Pitts Special was produced. At that time it was a partnership between Curtis Pitts, Herb Anderson, and Doyle Child, and they were building the 200-hp S-2A under the name Aerotek in the old Callair manufacturing facility in Afton, Wyoming. Then came the certificated S-1S single-hole, the S-2S 260-hp single-place bird, and the S-1T 200-hp constant-speed one-holer. Then Frank Christensen burst on the aerobatic scene with his Christen Eagle, and shortly thereafter, he bought Aerotek and renamed it Christen Industries. Almost immediately, he produced the 260-hp S-2B two-place machine, which is probably the most recognized and most common of the Pitts breed. It remained in production through another ownership and name change to Aviat until only two years ago. At that point, Stu Horn, the latest owner of Aviat Aircraft (he bought Aviat from Malcolm White and renamed the company) sought Curtis Pitts's advice and help in redesigning the S-2B.
The big Hartzell three-blade is standard equipment. Note the new gear leg profile. It looks like spring gear but isn't.
The Master's Influence
Since selling his share of the company, Curtis has hardly been sitting idle. One of his more significant design efforts has been the Model 11 Super Stinker. It was on this airplane that he introduced the innovative ailerons and wing that produced super high roll rates (350 degrees/second plus) and low aileron pressures while still maintaining a reasonable level of break-out force so that it wasn't difficult to find neutral. And he did all of this without spades! It was this so-called "Super Stinker Technology" that he brought to Horn's S-2C project.
As with most of Curtis' work, the new ailerons are deceptively simple, but wildly effective. Basically, they are nothing more than symmetrical ailerons (about 16 percent thicker than the wing at that point) hinged well back (about 23 percent), so they present nothing radically new. However, he shaped the nose of the ailerons in such a way that in the area of neutral, the aileron gap is sizable, but as the ailerons are deflected, the gap closes until they are effectively gap-sealed at full deflection. Then, to make things even better, he squared off the wingtips (much to the horror of Pitts aficionados) and ran the ailerons out even further for more roll rate. Like I said -deceptively simple and effective.
When Stu Horn and Aviat decided to do the Charley model, they wanted to make a major change in the S-2B's basic handling characteristics while staying within the constraints of the original type certificate. This meant the changes had to be extraordinarily effective while at the same time appearing relatively minor when viewed through the eyes of the FAA's certification guys.
Aviat's vice president of engineering, Ed Saurenmann, honchoed the project and actually designed the tail surfaces himself to go with Curtis' wing. As a longtime aerobatic pilot, Ed knew what he wanted and designed the tail accordingly. He was going for "square" handling-he wanted the tail to give the airplane the same stick forces when outside as when inside. This has always been a Pitts drawback-you could pull Gs relatively easily, but it was real work to push the same numbers. In fact, many pilots habitually slam the trim all the way down as they enter outside loops and such.
The square wing tips and tail bothered most Pitts freaks for a little while, but now they look "normal." The airplane pictured is the factory prototype "C" model, dubbed "Hot Stuff" for obvious reasons. It's actually one of the Anniversary "B" models they used to build as a prototype.
It was with all of this information in mind that I approached a friend's loaner S-2C. I spent some time circling the airplane, reacquainting myself with the various changes, cosmetic and otherwise. To anyone who has spent a lifetime around Pitts Specials, the new rectilinear wingtips and tail surfaces are something of a shock; however, now that the airplane has been around for a couple of years, they're beginning to look normal. These changes are obvious, but other subtle changes in the basic lines aren't. The "banana bellyî lower fuselage line has been brought up, which makes the airplane appear much leaner and sleeker. The control system torque tube has always driven the shape of the belly, but rather than changing the torque tube, they housed it in a small streamlined fairing and brought the rest of the belly up around it. At the same time, nearly the entire belly became transparent, courtesy of a series of Plexiglas panels, not unlike a pre-World War II fighter's canopy, only on the bottom of the airplane.
The landing gear has been modified to look like a faired spring gear, but it isn't. The only thing that changed was that the rear of the gear leg has been bent forward for a cleaner appearance. Herb Anderson designed it sometime back in the early 80s, but it was never put on an airplane. We'll come back to this new gear later.
The front of the canopy has been greatly cleaned up, with the formed windshield giving way to a flat wrap panel that lies back at nearly 60 degrees, which contributes to a sleeker look as well as lower drag.
One change that is obvious is the composite Hartzell prop. This single change is responsible for nearly $25,000 of the price differential between the B and Charley model.
The cockpit seems bigger, probably because of the glass belly.
When saddling the airplane up, everything about the cockpit is still basically like the B model. However, the fact it visually has no floor because of the Plexiglas seems to make it like less of a deep pit. Still, I scrounged up my own cushions to put me as close to the canopy as possible while allowing room for some head stretch during outside maneuvers. The Pitts' visibility is greatly affected by seating position, and landings depend on visibility.
The Pitts' two-place canopy has always been a controversial subject because it absolutely has to be locked tight before cranking it. So many canopies have been lost that most insurance companies no longer cover them or, at the very least, have a huge deductible on them. All sorts of locking schemes have been developed by owners as a reminder to lock them.
Aviat has a brilliant new series of canopy options that are bound to be popular with the troops. The new canopy slides right into the same mounts as the original canopy; the only modification is replacing the attaching screws on the front windshield with Camloc fasteners and mounting small locking tabs on the fuselage. The new canopy comes in two flavors: a dedicated single-place version that is so sleek it increases the top speed by a solid 12 mph (and is unbelievably sexy looking) and a convertible version that uses the standard single-place bubble but lets you fly with the front pit open by removing a Camloc-fastened panel in the front and putting the front windscreen back on. The double open cockpit arrangement is also still available.
Lighting It Up
If you've never lit the fire on an IO-540 in an airplane the size of a Pitts, you've missed one of life's true thrills. As the exhaust noise bubbles up between your feet and fills the cockpit the airplane rocks in response to the torque, AND there is simply no doubt in your mind that the airplane means business.
The relatively direct steering makes taxiing the airplane dead simple, almost Citabria-like, so long as you realize you can't see anything for about a 60-degree arc ahead and have to constantly S-turn. This is one of the big differences between the Pitts and most monoplanes. At the same time, however, the lack of visibility on the ground and during the approach is simply something you work around and never becomes an operational problem. This is one of the places where sitting high really helps.
Lined up on the runway, it's a good idea to paint a picture in your mind of the triangles on either side of the nose that are formed by the sides of the runway, the nose, and the bottom wings. It's those triangles that are going to tell you whether the nose is moving right or left, and it is a sight picture you must duplicate when you come back to land.
I lined her up and started the big barrel-shaped throttle forward. The acceleration is unbelievable. Even after having spent most of a lifetime in a Pitts, I still get goose bumps when that seat starts urging me forward. The forward push is directly proportional to the throttle movement, and the acceleration doesn't let up until you've left the ground. Although you can't see directly ahead without raising the tail entirely too much, it doesn't make any difference because the sides of the runway tell you all you need to know. Some guys hoist the tail high so they can see and then yank the airplane off when it's going fast enough, but that seems a little crude to me. I prefer to watch those edges, holding a slightly positive angle of attack until the airplane decides everything is right and takes off itself. That just seems more organic and in keeping with the airplane's thoroughbred spirit. It's an airplane that really responds to being made love to, and yanking it off the runway doesn't seem very sensuous to me.
Rudder movement during takeoff is minimal, depending on the wind. If there's a left crosswind, you can leave your left foot at home as all you'll need is a little pressure on the right pedal. Otherwise, it's just a little pressure this way or that way to keep the triangles on both sides of the nose equal.
The real surprise comes right after takeoff when you glance down at the airspeed. Best rate of climb is somewhere in the mid-90 mph range, but it's nearly impossible to glance down before the airplane has accelerated through that number. Just for the heck of it, I pulled it up to best rate and had to laugh at the ridiculous angle it assumed going up. No one needs to climb at that steep of an angle, but it's nice to know you can when you want to. At best rate I was clocking something well over 3,000 fpm, and dropping the nose to 115 mph still kept the needle nudging the big three. This sucker really climbs!
Wringing It Out
The obvious comparison for the S-2C is going to be the S-2B, and one of the absolute first differences anyone is going to notice is the aileron feel. The B has a solid, sometimes hard feeling to the ailerons, especially when you ask it for a lot of roll rate. As I arched up away from the runway, I twitched my hand, asking for a quick break out of the pattern, and the airplane whipped into a tight bank as easily and cleanly as any monoplane ever built. Not having a stick force gauge this is all subjective, but the aileron forces in all flight regimes have to be at least 30 to 40 percent lower than in a B, but they still have just enough break-out force that you know where your hand is. A lot of monoplanes have practically no break-out force, and finding neutral is strictly a visual affair.
Regardless of what many think, the new Charlie is definitely not a slightly warmed over "B" Model. It flies like an entirely different airplane.
On the way out to the practice area, I played with various power settings. I had flown the prototype Charley enough to know it was a fair amount faster than a B, but I hadn't flown any of the production airplanes. Again, it's hard to get an apples-to-apples comparison, but the airplane consistently indicates 7 to 8 mph higher than the B in similar situations. That means a 75 percent cruise of at least 175 mph is very real. According to the Shadin fuel totalizer, I was doing that speed on about 13.5 gallons per hour.
Out in the practice area, I had to grin because the first time I had flown a Charley, I immediately racked it into an inside rolling 360 and inadvertently slammed myself into the belts as I hit the 45-degree point. I was used to using a bunch of pressure every time the airplane went negative, but the Charley just doesn't need it. So, this time, as I did the same maneuver, I was loving the fact that pushing wasn't any more work than pulling, and, for once, the nose tracked the horizon without the rate changing. I rarely do that even in my own airplane.
I usually fly with just a hint of down trim so the stick lies in my hand. As I rolled over on my back, I found that hint of trim was exactly what was needed to hold the airplane dead level in inverted flight, hands-off. What a hoot! When pushing up from inverted, I had to remind myself not to drop my left hand and slam the trim down.
As I pushed up over the top, I let the nose down to 45 degrees and waited until it passed through 120 mph before attempting an inside snap. I say attempting because on the first one I forgot how much you have to unload the stick on both the Bravo and Charley. The Charley is more tolerant of those kinds of screw-ups, but on the Bravo it is really easy to bury the airplane in a snap and wallow around rather than breaking cleanly. Once I remembered, I could blur the horizon and stop it where I wanted (more or less, anyway).
Vertical rolls have never been one of my strong points, and there's no way I'm capable of accurately measuring how long up-lines are. However, because of the increased roll rate of the Charley, I was able to get virtually every single vertical roll I tried to come out on line and on point. Double rolls, which are always a gamble with me in a Bravo, happened equally as effortlessly, but I wasn't holding the line as well. Guess some practice and judging is called for.
Point rolls of any kind in the Charley are a kick. At first I'd overshoot them, or ricochet back as I hit them, but I finally got my touch lightened up and my sense attuned to the roll rate. I soon found I could fire off eight-points like a machine gun.
I know a lot of folks think a Charley is a warmed over Bravo, but while I was flopping around up there, I just couldn't disagree more with that assessment. Of course, I suppose it depends on your definition of warmed over, but to my taste, the airplane was a truly different machine. The unbelievable difference when transitioning inside to outside, as compared to the older airplane (or almost any Pitts, for that matter), borders on miraculous. Those of us who don't spend all our time in Unlimited aerobatic birds aren't used to an airplane that requires so little effort to play outside. The S-2C reduces the workload so much that it makes outside work really enjoyableÖwell, almost, anyway. I've always bragged that a Pitts doesn't know inside from outside, but that isn't entirely true because of the extra pressure required outside. With the Charley model, my brag is absolutely true. It doesn't care which way your head is pointing.
Because of the new tail design, the airplane needs virtually no forward pressure when flying inverted and the stick pressures are the same inside and outside.
I'm certain there are a lot of Advanced and Unlimited pilots reading this who disagree with all or part of what I've said, but there are many more Citabria and Decathlon pilots out there who are the ones I'm actually talking to. By the time a pilot has climbed the ladder to Advanced or Unlimited, they have lost the ability to be amazed by great leaps in performance because everything they fly falls into that ballpark. For the guy out there who is bashing around in a Citabria, the first time in a Charley model Pitts is going to make you think you've died and gone to acro heaven. Also, one of the things that makes it such a good airplane for even the low-time acroguy or gal can also be said of almost any Pitts-they are probably the most forgiving advanced aerobatic airplane in the world. Their spins are totally predicable, and they let you know well in advance of any upcoming surprise. As long as you get some spin training so you recognize what you're in, this is a very hard airplane to get yourself into trouble in (as long as you have altitude).
And then there's the landing. Okay, I'm going to say this one time, as loudly as I can, and on this score, I AM qualified to speak: The Pitts Special's reputation as a hard airplane to land is about 95 percent BS. Yes, it is a damned hard airplane to land and make look good, but it is NOT a hard airplane to land and be safe. This again presupposes some proper training. In my experience in my little Pitts checkout school, I find most folks land the Pitts too fast and are afraid of them, so they start fighting the airplane the second it touches the ground. They also don't fly good approaches, which is where the problems almost always begin. This goes for some Pitts instructors, as well.
Landing a Pitts requires that you know when to leave the airplane alone as well as when to do something. In every aspect of its personality, the airplane will do only what you ask it to do, and it will keep doing that until you ask it to do something else (go back and reread the last sentence). So the key is knowing exactly what you want the airplane to do. Yes, landing a Pitts can be a challenge, but it is also one of those challenges that anyone (I repeat, ANYONE) can conquer, and in so doing experience a feeling of real accomplishment.
As I motored back to the airport, I decided to try a number of different approach speeds and approaches. I came into the pattern at about 15 inches of manifold pressure, which put me at about 120 mph, with the cowl flaps open and the engine cooling down. Then, as I came abeam the numbers, I closed the cowl flaps and brought the power back to the stop. We didn't have much wind, so I hesitated before turning in, which turned out to be a mistake. As that big prop flattens out, the airplane practically stops, and holding 100 mph put me more nose down than expected. The result was that I needed a touch of power as I came around to the runway, rather than needing my customary slip to a landing. I always fly an angled approach to centerline, which keeps the runway in sight all the way to touchdown (if you loose sight of the runway for even a second, it's because you screwed up the geometry). This worked out fine, but I wasn't happy with the flat approach, so the instant the gear touched, I powered up and literally leaped back into the air.
Back on downwind, I did the same thing, but this time I tightened up the approach. This time, I had enough altitude to use a nice little slip, which let me come over the numbers with plenty of energy and low enough that the airplane settled into that characteristic Pitts sweet spot in ground effect. Once a Pitts is in that special spot, the landing will be a good one. And it was. All three kissed the pavement, gave me a tiny little hop, then settled down and rolled straight.
Any Pitts, if landed straight, will roll straight until it goes down through
about 50 to 60 mph, but the Charley just kept rolling while my feet got ready
to correct a little foray one way or the other. But there was none. The airplane
must have been down around 35 mph before I had to tap it a couple of times to
keep it straight. This is the same way the prototype was, and I thought that
was a fluke, so it was nice to see the production birds were just as straight.
I wound up shooting a half a dozen landings, each time letting the airplane
roll for a long, long way to see how it behaved, and each time was better than
the last. I messed with different speeds over the fence and found this airplane
was happiest just on the high side of 95 mph, but 100 is probably a more practical
number as it gives a hint more float.
This last point, the way the Charley seems to track a little straighter on the
runway, makes absolutely no sense to me. Even though the gear legs are a different
shape, the geometry is still the same. And touchdown is still around 70 mph,
so there is no logical reason for it to be more mannerly on the ground than
a Bravo. It doesn't land like a Citabria, but it is still probably the best
Pitts yet on ground handling. Incidentally, a normal Pitts checkout for a pilot
with a little tailwheel time (15 to 20 hours) can generally be done in six to
eight hours, depending on the student's background. In the Charley, the time
might even be shorter.
There's a tendency to compare the Pitts to something like an Extra 300 or Staudacher,
which isn't really fair. The Pitts S-2C is not an Unlimited category airplane,
but it is still more airplane than 90 percent of the pilots in the world actually
need. More important, it is absolutely superb and greatly improved from the
S-2B. To be honest, I've never loved Bravos because they lack that certain "something"
Curtis always put in his airplanes. In the S-2C, however, it can honestly be
said that the hand of the master is back, and we are all benefiting from it.
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