AGAC AA-1

With fighter-like handling and a sharp stall, this slick little sportster was a handful for its intended mission.

Originally designed by the one and only Jim
Bede, the AA-1 was initially going to have
folding wings, and fit in a two-car garage.

For those who want to fly on a tight budget, the diminutive Grumman AA-1 certainly seems an appealing choice. Priced consistently below other two-seaters (and down in the territory of an average automobile), it's a relative bargain. Plus, it's faster, more modern, structurally simpler and is, well, sexier than airplanes like the Cessna 150/152. It appears to be an ideal choice for pilots who simply want to get aloft for as little money as possible.

But there's a raft of caveats facing anyone considering the purchase of an AA-1. This is an airplane that, though marketed as a primary trainer, is not well suited for the task when compared to more docile designs like the 152 or Tomahawk. It has handling and performance quirks that make it an airplane to be approached with caution.

A different kind of airplane

Most striking about the AA-1 (and indeed, all of the Grumman singles) is how different it is. For one thing, the AA-1 is largely glued (bonded) together, instead of riveted. This gives it tremendous structural strength, and a very smooth surface finish.

The materials, too, are unusual. The cabin is made of an aluminum honeycomb sandwich, again bonded together. This produces very stiff, lightweight panels.

The wings have big aluminum tubes for main spars, which double as fuel tanks (the caps are out near the wing tips). There are no fuel gauges as such: Instead, a clear plastic tube with fuel in it runs up each sidewall. The pilot actually gets to see the fuel level in the tanks directly.

Examination of the tail surfaces shows that the vertical and horizontal stabilizers are identical. In fact, they're interchangeable. The same goes for the wing panels.

The main gear sports fiberglass leaf spring legs (Grumman called it "face saver" gear) and a nose gear sprung with torsion bars rather than an oleo strut. The nose wheel is not steerable. Instead, it casters, and the airplane is steered with the brakes. This permits extremely nimble ground handling.

And last, but not least, is the canopy. Not only does it lend a certain panache to the airplane, it gives it visibility that's second to none. It can even be opened part way in flight when the weather gets really hot.

Origins
The AA-1 started life in 1963 as the BD-1, the first design from the radical designer and entrepreneur Jim Bede. For those not familiar with Mr. Bede, he's the same fellow who made waves a couple of years ago with the BD-10J, a homebuilt (yes, homebuilt) supersonic (yes, supersonic) jet design. Bede had a penchant for designing airplanes that are tremendously exciting in concept, yet never seem to come to fruition for one reason or another.

The idea behind the BD-1 was simple and not exactly new: create a cheap, simple aerobatic airplane with folding wings that could be towed home and parked in the garage. That single requirement led to a string of aerodynamic and structural compromises that profoundly affected the design of the airplane and its performance (more on this later).

Originally, the airplane was supposed to sell for, believe it or not, $2,500 (albeit for a stripped-down version with a rebuilt engine). Needless to say, that target evaporated rather quickly—though the AA-1 did eventually sell for somewhat less than the competition.

Bede ran into financial troubles (another hallmark of his career), and by 1966 he had been ousted from the company. Russ Meyer (later of Cessna fame) was named president, and the company was reorganized as American Aviation.

A redesign and certification effort was launched, and the airplane obtained a Type Certificate that same year. Two of the early goals—folding wings and aerobatic certification—were abandoned along the way. It proved too difficult to engineer a folding wing design that would satisfy the FAA in terms of being foolproof.

As far as aerobatic certification was concerned, early flight testing showed that the AA-1 would never cut it as an aerobatic airplane. A 1971 paper written for the SAE by American's chief engineer, William Seidel, said, "The flight characteristics of the original airplane were, in general, quite bad. The aircraft presented poor stall characteristics which resulted in sharp rolls to the left or right during a stall. Aileron control power was low, resulting in the inability to land the aircraft safely with moderate crosswind components. Static longitudinal stability was low, resulting in low stick forces and high loadings."

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To address those shortcomings, several design changes were made. An anti-servo tab was added to the elevator, the control surfaces were aerodynamically balanced, the elevator gained a centering spring, and the elevator control geometry was altered to reduce its sensitivity. Stall characteristics and climb rate were addressed by the addition of stall strips and extended wingtips.

The changes helped, according to Seidel's report, but they still left the AA-1 short in the aerobatic department. "Good stall characteristics were easily obtainable and smooth stall recovery resulted. Extensive spin tests showed that aerobatic spin recovery requirements could not be met with simple or readily available modifications. At this point, the aerobatic spin program was dropped."

The first AA-1s, dubbed Yankees, were 1969 models. The airplane was a snappy performer, with a high roll rate, marginal stability, good speed, and handling that was widely described as "fighter-like." The fighter analogy was even carried to the point that the company sold airplanes painted like WWII fighters for a while. Pilots loved it.

But, the airplane had real problems. The airfoil produced an abrupt, sharp stall and wing drop. It also built up induced drag very rapidly at low airspeeds—getting "behind the curve" in a Yankee was a sure-fire way to make an unplanned arrival someplace other than on the runway. It didn't climb well, couldn't carry much of a load, and had short legs. But it was fast and fun to fly, as long as the speed was kept up.

Spin behavior was poor. The airplane was placarded against spins, and the manual warned that letting a spin go past one turn could result in an unrecoverable mode.

A total of 459 AA-1s were built between 1969 and 1971, when it was discontinued in favor of the AA-1A Trainer, an airplane with a redesigned airfoil that made the stall somewhat more docile and addressed the induced-drag problem. Other changes, like a redesigned exhaust, also made it a bit more livable. A total of 470 of these were built, as 1971 and 1972 models. Reportedly, the changes made the airplane easier to handle—though it still dropped like a brick with the power off.

In 1973, the AA-1B supplanted the AA-1A. It boasted an increased gross weight: 1,560 pounds., up from 1,500 (every ounce counts in an airplane this small). The AA-1B was available in two versions: a trainer version with a "climb" prop, and a sportier version with a cruise prop that added a few MPH to the top speed. Given the airplane's marginal climb performance, the climb prop is probably a better choice from a safety standpoint. A total of 634 AA-1Bs were produced.

For the 1977 model year, three substantial improvements were made. The 108-HP O-235-C2C engine was swapped for an O-235-L2C with 115 HP, with a welcome improvement in performance. Gross weight went up again, to 1,600 pounds. And, finally, the tail was changed to improve stability and handling through the use of a significantly larger elevator. The two versions were called T-Cat (for the trainer) and Lynx (for the sport version). Production ceased in 1978.

Lots of compromises

Design of the AA-1 was driven more than anything else by the original goal of towing it behind a car and being able to park it in a garage. In a way, the Yankee was designed as a trailer rather than an airplane.

Those requirements meant several things. First, the overall width, wings folded, had to be less than eight feet so it would be street-legal. That resulted in an elevator only 7.69 feet across. That's small—one of the first things you notice as you walk up to a Yankee is the diminutive size of the tail surfaces. Since cost considerations dictated that the vertical stabilizer must be identical to the horizontal stabilizer, it turned out small, too.

To make the airplane short enough to fit in a garage, the fuselage was made short and stubby. The wings, too, had to be short, since they couldn't extend past the tail in the folded position. The wingspan came in at 24.46 feet, or a shade over 10 feet per wing.

The small wings, in turn, meant high wing loadings for a trainer—around 15 lb./sq.ft., as opposed to 10 lb./sq.ft. or so for a Cessna 150. The Yankee had a wing loading more like that of a high-performance single (say, a Mooney) than a primary trainer. That meant higher approach and landing speeds, and coupled with the low aspect ratio a very high sink rate.

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The wing spar is tubular rather than a built-up beam as is usually found. Again, simple, inexpensive and very strong. It allows all the ribs to be the same, for simplicity. It also would have made the folding mechanism simple and robust. But here too there are compromises. Being tubular, the limiting factor is its strength at the point of greatest load, which is inboard. It's stronger than it needs to be outboard, but also somewhat thicker and heavier. The spar was also used as the fuel tank: another brilliantly simple idea, but another one that has significant consequences. The fuel has the ability to slosh the entire length of each wing, which means that should the airplane get into a full-on spin the fuel could move out towards the wingtips, changing the angular momentum, flattening the spin and making it unrecoverable.

Performance and handling
If speed per dollar is what you want, you're unlikely to find a better deal than an AA-1. For the price of a Honda Civic, you'll get an airplane that will walk away from a 152 or Tomahawk. Add to that a very high roll rate, great visibility and light controls, and you've got a lot of fun for not a lot of cash.

But, the principle of TANSTAAFL (There Ain't No Such Thing As A Free Lunch) really comes into play here, particularly with the earlier airplanes.

Climb performance is not great, especially with airplanes that have small engines and cruise props. It's absolutely critical to keep the airspeed up to keep clear of the induced-drag demon, and that means shallow climb angles. A short-field performer it's not.

High density altitudes and high weights, too, have a strong adverse effect on takeoff performance. Some owners report that you can forget about climbing much above 5,000 feet on a hot day at near-gross weights.

The panel is well laid out. The fuel selector
is below the throttle.

Landings can be made in a short distance by taking advantage of the airplane's high sink rate. That can be a useful tool in the hands of an experienced pilot, but novices must beware. Low approaches should be avoided.

Low-time pilots also need to be careful of the approach speeds. While they should be no problem for someone used to coming down final at 80-85 MPH, they're significantly higher than those for a Cessna 152. That can really throw off a student, and many have come to grief with botched landings.

The stability, particularly longitudinal, is not the best. NASA did an evaluation of the AA-1 (the original model) and had this to say: "Oversensitivity of directional and longitudinal control system presented a problem on both takeoff and landing…too light in pitch."

The electric flaps are slow to move, and they don't do a whole lot, in any case—on the original AA-1 they reduce the stall speed by all of one mile per hour, from 66 to 65. On the AA-1B, with its different airfoil, the flap-up and flap-down stall speeds are 62 and 60 MPH, respectively. Compare this to the lower wing-loading Cessna 150, which has stall speeds of 55 and 48 MPH.

Fuel foibles
The fuel system on the AA-1 is a mixture of the good and the atrocious. The good points are few, so we'll dispense with them first. The selector is right where it's supposed to be, in plain sight, and has a good design. The selector points to the tank in use, and it's very unlikely the pilot will shut it off by mistake. Since the main spar is also the tank, it's unlikely to develop leaks. It may also be more crashworthy than other designs.

On the other hand, the gauges are a joke. While electric gauges are nothing to bet your life on, the AA-1's sight tubes are worse. Uncoordinated flight and turbulence have a drastic effect on the readings, as does a wing-low attitude. Also, we shudder to think about what might happen in a crash. The pilot has a plastic tube full of gasoline that's connected directly to the fuel tank located right next to his or her left leg. Not exactly comforting.

As if the gauges weren't bad enough, a visual check of the fuel is impossible unless the tanks are near full. Smart AA-1 pilots fly by the numbers, make the leg lengths short, keep track of fuel burns, and leave lots of reserve.

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Small wonder that over the four-year period we checked for accidents fuel exhaustion and mismanagement accounted for 15 of the 89 accidents—16.85%.

Mod multitude
The AA-1 is easily modifiable, and there are several desirable upgrades on the market. Most important among these is the installation of an O-320 engine. That essentially eliminates the lackluster climb performance, and it can lead to an increase in allowable gross weight that may offset the additional engine weight (depending on model). Best of all, though, it makes the airplane move along like the proverbial bat out of Hades.

Unfortunately, it also will burn up the airplane's 22 gallons of usable fuel at a prodigious rate. Not to fear: supplementary fuel tanks are also available, adding eight gallons or so to the fuel load. Just be careful with the added weight, however: the payload has always been marginal, and adding to the airplane's weight can easily turn it into a single-place machine.

Also on the list are odds and ends like gear cleanup kits and hat shelf extensions, plus opening cowls (a good idea) and a dorsal fin that improves stability (a must).

Souping up an AA-1 would seem to make it an ideal cross-country machine for two. Unfortunately, the Achilles' heel is payload. We once saw a used AA-1 for sale that had a 150-HP engine, two navcoms, an ADF, a transponder and an audio panel. It also had a placard on the cockpit sidewall that said "Total weight of passengers and fuel not to exceed 315 pounds." That's basically a one-person-plus-fuel airplane when all is said and done.

The two main suppliers of mods are Fletch-Air of Houston, Texas, an outfit that supplies not only mods, but is the best source of parts around for Grummans, and Air Mods NW, a Seattle-based mod shop.

Safety
Before all the Yankee supporters out there start sharpening their pencils to write us scathing letters, let's get three important points out of the way. First, the AA-1 has a safety record much worse than average for this class of airplane. Second, members of the American Yankee Assn. (AYA) who have undergone their proficiency training program in the airplane have a stellar accident record. Third, an undue number of AA-1 pilots involved in accidents have low time in type.

The important thing about the AA-1 is familiarity. Pilots who have been introduced to the airplane by a good instructor familiar with its qualities seem much less likely to have an accident than those caught unaware. This is an airplane that can, and will, bite if not treated with respect.

What kills AA-1 pilots? The leading cause in our last accident survey was the stall/spin accident. That's not all that unusual: stall/spins were also the leading cause of fatal accidents for the Piper Tomahawk and Cessna 150/152. Interesting, though, is that a higher proportion of AA-1 stall/spins were fatal. This suggests that the airplane's stall behavior is much more of a handful than other two-placers—and this is borne out by both test pilot and owner comments.

Fuel "gauges" are plastic tubes connected to
the tanks. Tube spars and fiberglass gear are
features shared by all Grummans.

Other leading causes of accidents are engine failure, fuel exhaustion, takeoff obstacles and stall-mushes. The latter two speak of the high induced drag found in the design.

The engine failure accidents, while from a variety of sources, can be at least partially traced to the earlier AA-1's tendency to overheat. The engine is rather tightly cowled, and tends to run hot—thus shortening engine life. A scan of ads in Trade-A-Plane confirms this. For many of the AA-1s, though the total times are not that high, most of the engines have had at least a top overhaul. It seems to come at about 1,200 to 1,400 hours or so. Later models (the AA-1C) had an oil cooler, which is available as a retrofit to earlier models. A wise investment, in our view.

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On the subject of safety, the crashworthiness of the design is, on the whole, very good. The honeycomb cabin walls and floor are very strong, and the spar is stronger than it needs to be (particularly at the tips). On the other hand, there are the sight gauges in the cabin, and no way out if the canopy should get stuck shut. Some means of punching through the canopy should be seriously considered.

Maintenance
The AA-1 is, thankfully, very simple. Only three areas of note turned up in the our last scan of Service Difficulty Reports, which was quite small to begin with. Five reports, covering three aircraft, told of corrosion on the main landing gear brackets. These should be looked at closely.

There were two reports of damage due to application of force to the horizontal stabilizer—probably from the old trick of sitting on it to move the airplane. It just can't take it on the AA-1; use a towbar.

There were also a couple of reports of debonding, a problem unique to Grummans. A 1976 AD mandated the installation of rivets along the control surfaces to control the problem, but all the bonds should be examined closely. The problem has decreased in recent years, and any airplane that's made it this long is probably going to be okay. With one exception, the only other type-specific ADs on the AA-1 were a few one-time fixes that go back to the 1970s; the exception is 85-21-2, which deals with replacement of the seat belt brackets. There are no onerous repetitive ADs on the type.

Though not concentrated in any one area, there were many reports of engine problems. The airplane's propensity for running hot calls for a thorough check of the engine's health before purchase.

While some known problem areas didn't show up on the printout, they should be checked nonetheless. The nosegear torque tubes can and do crack. Check for this by rocking the airplane up and down—if the nose gear clicks, you've got a problem. Brake wear can be a problem, so the binders should be examined closely. Chrome or stainless discs reportedly help here.

Owner's association
Membership in AYA should be considered mandatory. There's the aforementioned proficiency program, an insurance discount program, and a bimonthly newsletter replete with maintenance tips, classifieds and articles. It's also a good source for contact information—prospective buyers of AA-1s should try to find others who own them to learn more about the airplane and, if possible, get some direct exposure to it. AYA can be contacted at (530) 676-4292, or on the Web at http://www.aya.org.

Conclusions
For the used-airplane buyer, the AA-1C T-Cat/Lynx is definitely the airplane of choice. It benefits from a more powerful engine, improved elevator, and higher gross weight. Not to mention that the oldest of them is only 16 years old.

Unless a real bargain can be found, the original Yankee should be avoided. Its flight characteristics leave precious little room for error, and unless the pilot is willing to sacrifice whatever margin of safety the aerodynamic changes on the later AA-1s brought, it would be best to leave these airplanes alone.

Whichever version is picked, though, membership in AYA and a thorough checkout by one of their designated instructors should be considered imperative.

Owner comments
I own a 1974 AA-1B Tr-2. In all honesty I'd be lying if I said this aircraft didn't intimidate me at first. Hangar talk, pilot reports and numerous other spook stories about the quirks of the craft had etched some strong negative notions in my mind. As a result, the first few hours I logged in the AA-1B were with care and caution.

I strongly recommend ground time spent with the owner's manual and if possible with a pilot or instructor who has experience with the AA-1. The aircraft was designed for speed and agility, not as a glider. As a result, I think the greatest potential for a mishap occurs at low airspeed during the landing sequence. My airplane gets real sloppy when it slows down. The AA-1B stall speed increases radically with angle of bank [Ed. note – Induced drag, again.]. Kick the rudder hard on base to final and bam! Stall/spin. My worst fear at low altitude.

Unfortunately, many pilots have misgivings about the AA-1 series. I suspect transitioning pilots are not comfortable with high approach speeds, high sink rates and the rate at which trouble can develop. When you chop the power and drop the flaps, the bottom falls out from under you; if you're in the landing configuration, at low altitude and high density altitude, you may find yourself in a situation you can't recover from. The solution is to fly it hot all the way to the threshold, chop the power, trim it back and let it settle. I fly my landing sequence at 100 mph, 90 mph on final and don't chop the throttle until I'm sure I've made the pavement.

Most light single-engine production airplanes can't hold a candle to the AA-1B in speed and handling characteristics. I've enjoyed every minute of flight time in my AA-1B and have become a better pilot learning to fly it.

Andrew Mayes

I've been the owner/operator of two AA-1s the first a '75 "B" model, the second a Lynx. Of my 1,300 hours of flight time, 800 has been logged in the AA-1.

Since I am 6'2" and 240 pounds, you might think that the cabin would be a bit snug for my stature, but quite to the contrary. There's ample head- and legroom, and I have no trouble with full control movements. The seats are comfortable, and most vital controls fall readily to hand. Filling the other seat does tend to fill the airplane, both in cabin space and weight. Depending on the weight of the passenger, some fuel is left behind. When flying solo, however, I normally fill the tanks, which gives about 3 hours, 20 minutes' flying time. I fly maximum two-hour VFR legs and 1-1/2-hour IFR legs.

Cabin noise levels are high. I have measured cruise noise levels in the vicinity of 95 dBA at ear level, with higher levels near the canopy seals and against the windshield. The use of headsets is a definite must.

Pilots who haven't flown the AA-1 before are first impressed with the visibility. Next is the roll response. Most comment, "It ain't no Cessna." When flown in IMC, particular attention is needed to keep the wings level and not to overbank during turns. A light touch on roll is definitely needed. During VFR maneuvering, however, the roll rate is a definite grin maker.

Airspeed control in the pattern is definitely needed in this airplane. Due to the type of airfoil used, the slower the airplane goes, the slower it wants to go due to induced drag. New pilots transitioning into the type cannot use Cessna 150/152 approach speed numbers. They won't work in the Grumman, and are guaranteed to produce a generous sink rate—something you don't want on short final, close to the ground. Full flaps on the two-seaters do not give the same results as those on the C150/152, but do impart a very solid control feel to the ailerons in the landing pattern.

I use 80 knots as a reference speed on short final, bleeding off to 65 at touchdown. Power is needed to control the descent rate all the way to short final. Touchdown on the main wheels is an absolute must. The nose gear strut is springy, and nose gear-first landings will always end up in an ungraceful and potentially damaging porpoise action down the runway.

The full-castering nosewheel does have a drawback in that if the anti-shimmy washers are not properly tightened, the nosewheel will shimmy. This sets up an uncomfortable vibration in the airframe. A&Ps not familiar with the type often fail to tighten the washers enough, so it's necessary to gently remind them.

The airplane is not maintenance-intensive, in my opinion. I do as much of my own maintenance as FAR Part 43 will allow. There are no complex systems on the airplane, so I feel comfortable doing those procedures.

I have found the AA-1 to be a cost-effective airplane. Low cost for maximum effective fun. Properly equipped, some modest IFR work is possible, and I find that to be able to punch through the low stratus deck typical of southern California to get to a VFR destination is pleasing. For a pilot who wants to build time, fly a responsive airplane and is not worried about time to destination, the Grumman two-seater is the ticket.

David Ming
San Diego, Calif.

My first takeoff in my husband's 150 hp AA-1 was a little squirrely, as I wasn't used to the differential brake steering. With a little practice I found that the rudder took over very quickly, though. Once off the ground, I found the airplane to be a smooth, crisp-handling machine that climbed out at about 1,000 fpm at 110 mph. I later had a chance to fly in a 108 hp AA-1. The takeoff roll was much longer and the climbout was nothing compared to our airplane. In the air it flies the same.

I got a thorough checkout from an AYA instructor, including a full stall series. The base-to-final cross control stall demonstrated how quickly the airplane can flip over onto its back if you're not careful. At 4,000 feet it's fun, but in the pattern you wouldn't have a chance. Proper instruction with an instructor who is familiar and experienced with the airplane is vital to a safe transition. I can see why the airplane got such a bad reputation back when it first came out and not even the instructors knew how to fly it.

Cindy Cavanaugh
Raytown, Mo.

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