Text and photos by Budd Davisson, Air Progress , Feb, 1978
From the EAA's think tank to you . .
AKRO: The ability to viciously cavort; Those maneuvers directly preceding a violent wretching of the abdomen muscles; Fun of a masochistic nature. SPORT: A game in which the challenge can be readily met; A good guy, liked by all; A form of relaxation usually involving strenuous, s but not necessarily exhausting, exercise.
Put them all together and they don't, as the song says, spell "mother." What they do spell is "Akrosport" and, if the definitions are taken literally, it is defined as a violently maneuverable good guy that gives one the ability to put your already eaten lunch in your vest pocket and presents a challenge most of us can master with little or no sweat. Is that the Akrosport? If not, it's darned close.
The Akrosport is the latest official biplane offering to come floating down from the EAA's Wisconsin think tank to amaze and delight us plebians. It was the logical son of a logical progression that began in the 1950's when the EAA was formed and everybody went about whittling out designs. Come the early '60's and baby biplanes were all over the place like fleas on a Tijuana hotdog. However, they all had similar traits; they were so tiny that they approached and landed like cast iron hockey pucks . . . fast and hot. Many wingtips were scrunched. After maybe ten years of this, Paul Poberezny, the rag and tube guru of the EAA, decided there had to be a better way. Not only were these bitty bipes hot, but he couldn't fit in most of -them. Out came his handy book of aeronautical rules of thumb, he called a few knowledgeable folks, and they whipped together a bipe for the masses, the EAA Biplane (in naming airplanes, imagery wasn't their strong point). So for the next few years the EAA bipe satisfied the need for an easy-to-fly, big-enough-for-a-beer-belly biplane.
When the early 1970's, all was not roses in the Wisconsin hinterlands. For one thing, aerobatics had been coming on strong and the EAA bipe was not known for hard driving, varicose vein acrobatics. The need was felt for a fully acrobatic version of the EAA bipe that would let a pilot feel like he's flying a Pitts without having his pucker factor go off the scale every time he sees the runway in front of him. The parameters were simple enough; the airplane would have to offer most of the acrobatic ease and capability of the Pitts but have economical construction and easy handling characteristics that most pilots could hack. The Akrosport was born.
The story is, Poberezny and EAA HQ talked to everybody who is worth talking to when designing the Akrosport and it's a fact that Curtis Pitts had his say about what was done. The final result is a straightforward appearing biplane significantly larger than a Pitts with Hershey bar wings and widely splayed landing gear. But, that's all history. The Akrosport is now 4 years old and there are at least 14 flying with engines ranging from 100 to 200 hp. The basic plans cost $60 for an airplane utilizing an M-6 airfoil, which is the same as the flatwing Pitts. For an additional $15 You can get the plans for the Super Akrosport wing, which is an almostsymmetrical 23012 section that's much better suited to outside maneuvers. Approximately 1000 sets of plans have been sold and, if the usual four or five to one ratio holds, about 250 are actually being built. If you believe the FAA's statistics that only one out of ten homebuilts started are finished, then eventually we'll see a minimum of 25 Akrosports flying. They will obviously top that number.
Interestingly enough, the effort to design airplanes that theyfeel better fit the average market has placed Poberezny and the EAA hierarchy in a dicey position. Some plans vendors are mad as hell because they feel the EAA has used the HQ facilities and membership money to go into competition with member-designers who are selling plans. They are right. That's exactly what the EAA has done. However, there are others, myself included, who say that's what the EAA is for. If the independent designers haven't been filling all the marketing niches and there is a need for a better or different airplane, then Poberezny doesn't have much choice but to design what is needed.
Of course, there's also the argument about exactly how good the EAA designs are. For instance, in the case of the Akrosport, at least two problems manifested themselves in the first airplanes built. First, the cg could wind up right on the front of the envelope, depending how the aircraft was equipped. Secondly, and more important, the size of the landing gear tubing-originally called out and since changed-wasn't sufficient to take the compressive loads of landing. There have been at least three known cases of landing gear Vees collapsing and the aircraft being substantially damaged.
From a purely personal point, when I examined the Akrosport carefully, I found it to be what you would expect for an airplane that was being built as fast as it was being designed, maybe faster. It's obviously heavier than it needs to be, because in all probability the structural analysis was of a rather basic nature, utilizing overlapping assumptions to make certain everything is kosher. This isn't a bad way to go, but it does add weight and it sometimes lets things slip by because there has been no finite analysis of every structural member. As it happens, this is the way almost everybody designs airplanes, homebuilts and otherwise, so the Poberezny design team is certainly not guilty of anything unusual. It does, however, give some folks amMunition for taking potshots at the EAA.
The design being what it is, aimed at the masses and sure to be built in large numbers, I wanted to fly the airplane badly. I was curious as to how well the EAA had met their design goals. However, for at least three years, every time I got ready to fly the EAA's own Akrosport, something got screwed up in my schedule. It wasn't until a plans-built version was finished at my local aerodrome, beautiful Sussex International in New Jersey, that I finally had the opportunity to fly the airplane. Even then, it took a couple of years to get around to it.
N869M is the second plans-built Akrosport to be finished. The fact that it was finished as fast as it was is the result of several unusual situations. Jim Inman, the owner, had gone to Oshkosh with a wad of bills in his pocket determined to come home with an airplane. He was tired of rattling around in his T-34 and was hot for something else. He came home empty handed because there just wasn't anything available that fit his needs. What did fit his needs was the EAA's Akrosport he saw being demonstrated and the Akrosport components display that Wag-Aero had in the exhibit building. His solution? Have an Akrosport built! Enter Bill Shaft, local A & P and all around bolt bender; Bill did most of Inman's T-34 maintenance and is the only guy we trust to work on our Pitts. He's good at what he does and almost never misses an Oshkosh. He's a torch and dope man who knows and digs flying machines of the "Wisconsin Weird" variety. What more can you ask for?
To compress the time frame of the project, Inman opted to purchase all the finished components he could from Wag Aero. This included a welded up fuselage and tail feathers, wood and spar kits, welded landing gear, and a few other bits and pieces. This doesn't do much for keeping costs down but it does wonders for the economy of Wisconsin.
Even with all the components in house, having all the skill in the world, and working. four to six hours a day, it still took Shaft ten months to get the airplane into the air, something worth remembering if you're contemplating a homebuilt project.
Anyway, it did fly and Jim spent an inordinate amount of time bombing around the countryside getting his rocks off by drawing obscene pictures in the sky with his smoke system. Then, after 168 hours, the glitch in the landing gear design caught up with him. During a landing the airplane was behaving entirely normally, then for no reason started to swerve to the right. Inman dropped the hammer again and took off wondering what the hell was going on. He tried it again with the same results then noticed he could see the right wheel pant above the lower wing and he knew he was in trouble. The right gear leg had failed in compression, letting the wheel move up about a foot. Heaving a sigh of resignation, he set it down in the grass, rolled-out on one gear leg and held the right wing up as long as possible. Eventually the right wing tip touched and he sucked his head in like a turtle. The nose caught, and he would have wound up standing on his head in the dirt had the airplane not been caught and held off the ground as it went past vertical by a stand of small trees. Three wing panels and the gear needed tons of patching to get it back in the air. Since then, he's had little or no trouble with the airplane.
Then it was my turn to try it out. The first thing I noticed when strapping the airplane on was that Poberezny and crew certainly gained their objective of adequate cockpit room. It's wide, it's long, and it's deep. With a little forethought when building, I'd be willing to bet that the airframe would accept somebody up to around 6'5" or more. There's plenty of leg room, and head room is naturally unlimited.
The Inman/Shatt Akrosport has a complete electrical system, something that probably contributes to the cg balancing on the forward edge of the envelope. There are lots of times when it's handy to have a starter, but they sure do weigh a bunch. Anyway, I availed myself of the electrical system and lit the burner on the 180 hp Lycoming first try. Taxiing out I was super impressed with the rudder/ tailwheel ratio. The steering was positive, extremely positive, but far from sensitive. The airplane followed my feet with practically no tendency to overshoot when turning. I meant to look at the tailwheel springs to see if they were pretty stiff or what. I also noticed that with a 2" cushion under the parachute, I had a fair amount of visibility, not a lot mind you, but enough that with plenty of "S" turning I felt comfortable. A Pitts in the same situation is a bit blinder, although neither airplane is going to qualify as a C-172 in the vis department.
As I swung around on the runway to clear traffic I automatically started bringing the power up, as I came back towards the centerline. I was already moving at a pretty good clip when I eased the go-knob the rest of the way in, but I was unprepared for the rate at which the runway markers started flashing past the wing tips. The airplane is fairly heavy for its size, but you sure wouldn't know it by the way it leaps off the ground. I barely had time to get the tail up before we were gone! Those larger-than-Pitts wing panels really do work! Also, when I had it up on the main gear it felt so positive, so solid, that control was no problem. I was simply driving it with my feet. Actually. control isn't needed anyway because the airplane launches itself long before you can get in much trouble.
Keeping the needle stuck on 85 mph during climb out made me feel as if I was laying on my back. The nose altitude at that speed is high, I mean really high. I was leaving the ground behind at the rate of about 1500 fpm, so by the time I cranked into a ninety left and forty-five right, I was at a solid 1200 feet agl and going up fast.
It was a clear, cool autumn day, and after six solid weeks of typical New Jersey grungy weather, we had earned it. Climbing out away from Sussex, the Akrosport felt as if it was going to be by far the best pinnacle from which to survey such a day. The plane's comparatively big flight deck, the excellent visibility, and the overall feeling of aerial well-being was doing its best to put my mind in another dimension. I looked down at my gloved hand wrapped around the fighter type grip on the stick and giggled a bit (I do that a lot). My mind's eye was watching the quickly yellowing afternoon sun turn the cockpit interior into a sepia-toned print out of a late movie. The gloved hand that moved the stick and rotated the horizon belonged not to me, but to Richard Arlen, Wallace Beery, or any one of a dozen other of the late movie aces. I was getting off on the experience of watching myself fly a fun machine on a fun afternoon. I wasn't experiencing, I was spectating, watching myself as if on the boob-tube, the perimeters of the picture being the frames of my own goggles. The plot line was not mine, but that of a thousand plotless aviation flicks that constantly hover around the edges of my consciousness. What do I do, where do I go? Where will that virile looking gloved hand take me? To fight the enemy? To chart unknown wilderness? As a spectator I didn't care. Anywhere in the air was someplace else, and that is the function of a machine such as the Akrosport, to transport one's mind, if not body, to another place, another time.
But the time is now and the place is here, so when I pushed over into level flight, it was back to the business of evaluating. Daydreaming is fun but I wasn't there to dream and, as I felt the controls beginning to stiffen up with speed, I could see that the intrusion of realities make for short lived dreams. The reality of the Akrosport controls is that they feel nice but are not what I'd like to sec in such a spirited looking, spirited moving airplane. I guess I could be called unfair for comparing the Akrosport's controls to those of a Pitts, but why not? That's what the Akrosport is supposed to be in the everyman's market, an "almost-Pitts." But the controls aren't even close to "almost." For one thing, the ailerons just don't do what they should for the airplane. While they aren't particularly heavy, they are way down the scale in effectiveness, so roll rate and roll response suffer. They just aren't as clean and responsive as I personally think they should be. The "super" wing with the 23012 reportedly has much crisper ailerons. However, the ailerons can be lived with, but the elevators can't. The elevator pressures are heavy, and any maneuver needing a lot of elevator is going to use up a lot of arm. Later plans incorporate a servo tab that does wonders for the elevator pressures. (Ed Note: These points have probably been addressed since writing this paragraph, so check around before taking my word for it.)
It should be mentioned that this particular Akrosport and its severe case of the noseheavies is supposedly not typical of all Akrosports. However. the EAA happily admits that, as designed, the Akro's cg will be somewhere near the front of the envelope because it makes a safe, more stable handling airplane. The Inman/Shat airplane compounds the problem by the inclusion of the electrical system, something the plans don't take into account. Also, the plans put the fuel tank almost entirely in front of the cg with a smoke oil tank located behind it. I'd like to see the fuel tank slid back to where it at least sits right on the cg. Even in stalls, the noschcavy balance of the airplane changes its personality all out of proportion. The airplane just about can't be stalled because it runs out of elevator at about 68 mph and just mushes straight ahead with the elevator full back. Even by accelerating the stall with "G", very little changes. I have no doubts that the little bugger has docile, straightforward stall characteristics, but you couldn't prove it in that airplane because I couldn't get it to break under normal conditions.
The "Akro" part of Akrosport is one of its strongest selling points, so I pulled and jabbed all I could to see if it lived up to its name. As it happens, I had broken a rib a couple of days earlier (Don't ask), so I was being just a bit conservative; but I managed to put minus 3.5 and plus 4.5 on the G meter with all my shenanigans, much less than I'd put on a Pitts in the same situation.
Quite honestly, the noseheavy nature of Inman's airplane did a lot to take the edge off some of its aerobatics. Some of the maneuvers, like snap rolls, were just plain work. Also, with the climb prop that's stuck on the Lycoming, every time I pointed the nose down to get some speed 1'd glance over and see the tachometer streaking past the 2900 rpm redline.
Anyway, as I arrived at altitude and packed some numbers into the airspeed indicator, I pulled up into a slow roll and found myself using a lot more forward stick than I'm used to. I love slow rolls almost as much as sex and ice cream (I said almost) and I was just a tad disappointed to see how hard I had to work to make it do its number. Oh no, its nothing nearly as bad as a Citabria or Decathalon. but the Akrosport is sure as hell no Pitts. Fortunately, it's got plenty of rudder so you can hang in there for a long time when doing point rolls. I never did get a good vertical roll out of it because I just couldn't get the speed and keep the prop under redline. At 170-180 mph I'd have to wait until I was almost established on the vertical up-line before I could hit the throttle and not overspeed the engine. Also, a combination of too much weight and drag combined with its slow roll rate to-make it damned difficult to get all the way around.
Inverted, I found that even with full nose-down trim I still had a sizeable amount of forward stick in it to keep the nose up, which is nothing unusual. I, couldn't fault its inverted performance, and I'm certain that it'd be a dream with the cg in the right place and the 23012 wing. As it was, I was doing 45-degree banked inverted turns and more or less holding my attitude. Again, it's no Pitts but it is still pretty damned good.
The first time I pushed it outside. I did so from the bottom in a push-up. That's when the elevator pressures and my damaged rib cage got into a minor argument. I ended up using two hands when doing outside loops to keep from leaping out of the cockpit from the pain. From 150 mph, it cruised right over the top of an outside loop as long as I remembered to ease off the -G". With negative G's on it, it gives a very distinct buffet when its about to make a fool of you by stalling, and all you have to do is relax the stick a bit to make it fly its way over. Going outside from the top had me wondering for a while if it was going to make it because the elevators just don't seem to be able to push it under easily. It’ll go under just fine, but you’re using some arm to make it go.
When spinning the airplane. I was prepared to have to fight to get it into a spin because of the cg problem. That wasn't the case . . . boy, was that ever not the case! As I brought the stick back and stomped the rudder, the wing whipped over the top as the nose tucked down and I found myself with a face full of wildly rotating New Jersey. It spins very nose down and as fast as any airplane I've ever spun (BD-5 and T-37 excepted). However, when I got on opposite rudder and began to release backpressure, it jerked to a halt almost before I was ready. I found I could do three to five turn spins and stop them much more precisely than I do in my own airplane.
As a normal rule, when I'm frolicking with an airplane like the Akrosport, I stay up until my hands turn green or I'm out of fuel. This time, however, after about 45 minutes, the two ends of my broken rib started talking to each other in a very uncivilized manner and I decided to call it a day. On the way back to the airport, I timed some rates of descent, power off, and found it to be about 1200 fpm at 90 mph and in a reasonably flat attitude. Considering the size and configuration of the airplane, that's hardly even a number worth worrying about. A lot of Wichita Sheet Iron settles faster than that.
I held a solid 85 mph on final and was interested to see that the visibility was only slightly better than a single-hole Pitts, but a gigungous amount better than the two-hole Pitts. Its nose attitude is low enough that you have most (most, not all) of a 3,000-foot runway in sight during the approach. I was carrying about 1300 rpm and killed it when I cleared the Bell Telephone gear grabbers at the end of the runway. I flared in a normal manner and suddenly found the runway leaping up into my peripheral vision, telling me I had better finish rounding out or I'd richochet off the runway by touching main gear first. I tugged the nose up to a three-point attitude and found asphalt touching the tires at about the same time. The touchdown was smooth enough, but I still got a little hop, which I'm told is part of the Akrosport landing game. Pitts have the same little hop built into their landing characteristics.
As I whistled down the runway (there wasn't a breath of wind to help slow my touchdown speed), I was pleased to find I wasn't doing the "biplane boogie," as I usually do in a ship this size. It wasn't rolling dead straight, but it wasn't scaring the hell out of me either. Because of the well ratioed steering, any time I needed to nudge things back into line, I just gently leaned on a rudder and that's where the airplane went. Many taildraggers have the rudder/tailwheel ratios set up such that any rudder at all sends you careening towards the bushes. We do a lot of things right in homebuilding; we've got better feeling control than does Wichita, more responsive airplanes, and generally stronger, better performing machines, but we often fall down in setting up tailwheel steering. The Akrosport, however, seems to be headed in the right direction (pun intended).
I shot three or four landings in the Akrosport before I put it back in the barn, and one other characteristic confirmed itself: When flaring, it seems to settle through ground effect much faster than a Pitts, either a single hole or two-hole model. It feels a little like the old flatwing Pitts, only more so. However, carrying just a few hundred extra rpm into the flare and then bleeding it off lets you come down in a more leisurely manner.
In general, I'd have to say that Poberezny et al have achieved their goal. While I had plenty of gripes about the airplane, I'm absolutely positive most of them were because of the cg problem on this particular airplane. Reportedly, this is not the case with all others. Its acrobatic capabilities are really quite good, even though you have to work to make it do its best work. Inman's airplane had the M-6 airfoil, so the semi-symmetrical one should be even better. It's really hard to compare its aerobatics with any other airplane without flying them in the box in front of judges, but I'd guess it about matches a two-hole Pitts in most areas except vertical maneuvers.
What the Akrosport represents is exactly what the EAA wanted: It is an acrobatic airplane with almost-Pitts performance and better-than-Pitts manners. One of my friends persists in calling it a "Pitts for grandfathers," and I think he's right, which ain't all bad. (Ed Note: now that I’m a grandfather, I think I resent—or resemble—what I just said.)
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