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The Aeronca Model 7 Champion -- more commonly known as the "Champ", or "Airknocker" -- is a —is a single-engine, two-seat, light airplane, with a high wing and fixed conventional landing gear. Designed for flight training and personal use -- and specifically developed to compete with the popular, legendary Piper Cub, entered production in the United States in 1945, spawning one of the most popular, and longest-produced, light airplane models in the world.

In addition to its large volume production by Aeronca, it was revived in variations by the Champion Aircraft Company in the 1950s and 1960s, and then again in further variants by Bellanca in the 1960s and 1970s, and by American Champion Aircraft in the early 2000s.

To take advantage of the new light-sport aircraft (LSA) category, the Champion was returned to production in 2007.

Design and development
The Aeronca 7 Champion line -- developed in the mid-1940s as a post-World War II response to the popular Piper J-3 Cub -- uses similar design features (already featured in Aeronca's wartime designs, the Aeronca Model T, Aeronca Defender, and Aeronca L-3), but also incorporates aspects of traditional Aeronca designs, including the internal main trusswork of the fuselage frame. Like its predecessors and initial rivals, the high-wing, two-seat plane has tandem seating, conventional landing gear (tailwheel-equipped), and a small piston engine.

As with many light aircraft of the time, the Champ’s fuselage and tail surfaces are constructed of welded metal tubing. The outer shape of the fuselage is created by a combination of wooden formers and longerons, covered with fabric. The cross-section of the metal fuselage truss is triangular, a design feature which can be traced all the way back to the earliest Aeronca C-2 design of the late 1920s.

The strut-braced wings of the Champ are, like the fuselage and tail surfaces, fabric-covered, and use aluminum ribs. Most Champs were built with wooden spars. American Champion has been using aluminum spars in the aircraft it has produced, and has also made the aluminum-spar wings available for retrofit installation on older aircraft.

Like the Piper Cub with which it competed, the Champ features tandem seating. However, while the J-3 model of the Cub is flown solo from the rear seat, the Champ can be soloed from the front, giving improved forward visibility, particularly on the ground and during takeoffs, landings, and climbs. The Champ offers far better visibility than the Cub, allowing 300 degrees of visibility to a front-seated pilot, and has a wider cabin than the Cub.

The landing gear of most Champs is in a conventional arrangement, though a model with tricycle gear was produced, and a model with reversed tricycle gear was tried. Conventional-gear Champs feature a steerable tailwheel and most have steel tube main gear which use an oleo strut for shock absorption.

One variant utilized sprung-steel main gear, and American Champion is using aluminum gear legs in its production model of the Champ. The tricycle-gear Champs use the steel tube and oleo strut main gear, mating these with an oleo strut nose gear.

Models 7AC, 7CCM, 7DC, and 7EC were approved as seaplanes, with the addition of floats and vertical stabilizer fins; the seaplane versions were designated the S7AC, S7CCM, S7DC, and S7EC, respectively. Float and supplemental fin installations are also approved for models 7ECA, 7GC, 7GCB, 7GCBC, and properly modified 7HC's.

Matching Aircraft: Friend and Foe
Two aircraft principally affected (and were affected by) the design of the Aeronca 7 Champion: These two airplanes are reflected in the design of the Champ, and vice versa, and their impact on each other was decisive.
 * Piper J-3 Cub, a rival airplane; and
 * Aeronca 11 Chief, another Aeronca airplane.

Champ vs. Cub
The original 7AC Champ, it is often said by industry reporters and historians, was developed specifically to compete with the similar, and very popular, Piper J-3 Cub, one of the most popular and influential aircraft of all time -- a 1930s design that, in slightly modified form, had also been produced for the war effort as the Piper L-4 Grasshopper, and was returned to civilian production immediately after the war ended in 1945.

Both planes were heavily used for training, as well as personal use, and the two were each other's closest competitors in the postwar market (no other comparable plane came close in popularity during the 1940s, until the advent of the very different Cessna 120/140). Each were high-wing, tandem-seating, two-place airplanes, with conventional landing gear (using a tailwheel) and joystick flight controls. In 1946, both were powered by a 65-horsepower, four-cylinder Continental engine, with no electrical system, fueled from a "header tank" between the engine and instrument panel. Neither plane had flaps. Both were "tube-and-rag" construction (welded steel-tube frame, wrapped in fabric skin), with strut-braced high wings using aluminum ribs mounted on a wooden main spar (in postwar production, Piper switched the Cub to an aluminum spar).

The Champ offered several specific "improvements" over the Cub -- starting with front-seat solo capability (Piper Cub pilots had to solo from the rear seat, to counter-balance the weight of the Cub's engine). This greatly improved visibility and safety. Visibility was further improved over the Cub with a higher wing, more upright seating for the occupants, and greater window area.

While the Cub's engine was largely exposed, providing much drag, the Champ reduced drag by a cowling completely enclosing the engine. The Champ also provided gentler, shock-absorbing oleo-strut landing gear, countering the bouncy landings of the Cub's rubber-bungee suspension, while apparently offering less drag.

The lower drag of the Champ resulted in a 5-to-15 mph speed advantage over the Cub, when using the same engine. The higher wing-loading of the Champ also provided a smoother ride in turbulence, made cross-wind landings easier, and reduced "float" on landing, making landings simpler. The Champ had snappier handling, and quicker pilot response to problems, but also required pilots to exert very substantial rudder/aileron coordination in turns.

The difference in drag and wing-loadings mean that the Champ is less likely to be tossed about in turbulence (a problem that causes many Cub crashes), but it also made the Champ more difficult to recover from a wing stall, and more prone to spins, two of the chief hazards of flight. A 1979 study by the National Transportation Safety Board rated the Model 7 series as -- among the 33 most popular light plane types in use in the 1970s -- by far the plane most likely to be involved in a stall/spin accident -- nearly triple the rate of the next-most-prone, its sister design, the Aeronca 11 Chief series, and nearly quadruple the stall/spin crash rate of Piper's J-3 Cub. (However, the same study, reported that the overal fatal accident rate of the Aeronca 7 family was 6.50 fatalities per 100,000 hours of operation, slightly less than the J-3 Cub's 6.68 fatalities.)

The Champ has a more roomy and comfortable cockpit than the Cub. Also, while the Cub has a two-piece "clamshell" door that opens the right side of the plane (windows up, door down), the Champ uses a conventional door, providing advantages and disadvantages; the Champ is far less drafty than the chilly-in-winter Cub, and easier for people to enter; but it is not as "fun" to operate (you cannot fly with the right side of the airplane open), nor as easy to load with cargo as the Cub.

Following Piper's suspension of production in 1947, they returned the Cub to production, modified to compete with the Champ as the Piper PA-11 Cub Special. Though the Cub Special used the same standard engine as the Champ (now fully streamlined by a cowling, as in the Champ), the Cub Special was also offered with an optional 90 horsepower engine, that offered noticeably better performance. An aluminum main wing spar replaced the wooden one, and fuel was moved from a header tank over the pilot's lap to a safer place in the wing. Piper's design changes allowed front-seat solos and sharply improved pilot visibility, neutralizing some of the Champ's advantages.

While the PA-11 Cub Special production was brief -- 1948 to 1949 -- Aeronca continued to build Champs during the postwar recession, until the end of Aeronca aircraft production in 1951, ending with the electric-equipped Aeronca 7EC Traveler variant.

Champ vs. Chief


The original Aeronca 7AC Champ was designed concurrently with the Aeronca 11AC Chief -- the Champ with tandem seating and joystick controls, and the Chief with side-by-side seating and yoke controls.

The intention was to simplify production and control costs by building a pair of aircraft with a significant number of parts in common; in fact, the two designs share between 70% and 80% of their parts. The tail surfaces, wings, landing gear, and firewall forwardâ€”engine, most accessories, and cowling, are common to both airplanes.[citation needed]

The Chief's side-by-side seating resulted in a wider fuselage for the Chief, than for the Champ. To enable the Chief to maintain the same level of performance as the Champ, the drag of the wider Chief fuselage was compensated for by a vertically shorter fuselage than the Champ, resulting in less headroom and sharply reduced visibility (the wing roots of the Chief were at eye level, requiring pilots to stoop under the wing to look sideways). With these adjustments, the Chief and Champ reportedly had the same performance on the same engine.

One other notable difference: The Chief incorporated a hand-lever in the cockpit for starting the engine;  the Champ required traditional hand-propping to start.

Of the two, the Champ was far more popular, Selling for $2,095, the Champ outsold the Chief by an 8-to-1 margin. However, both airplanes were widely popular in the postwar era.

Operational history
Built by Aeronca Aircraft Corporation, the Champ first flew in 1944, and entered production in 1945. As an economical postwar rival to the Piper Cub (which it largely improved upon), the Champ was popular with training schools who were training veterans returning from World War II, by the thousands, with government funding through the G.I. Bill.

The original model 7AC Champion initially sold by the thousands, peaking in 1946, as Aeronca developed the highest-volume production line in general aviation. Between 1946 and 1947, Aeronca was producing an average 30 light aircraft per day (peaking at 50 per day at one point). But 1946 was a momentary explosion in lightplane production, industry-wide. The postwar boom-and-bust of the late 1940s and early 1950s brought an abrupt end to the massive sales, and -- like the rest of the U.S. lightplane industry -- Aeronca production dropped to a small fraction of 1946-1947 sales.

Selling for $2,095, the Champ outsold the Chief by an 8 to 1 margin.

Engine upgrades in 1947, 1948 and 1949 resulted in the Models 7BCM, 7DC and the electric-system-equipped 7EC, all distinguished from the 7AC by a larger vertical tail than predecessors, to compensate for the greater torque and p-factor of the larger engines.

By the time production ended in 1951, the company had sold more than 8,000 Champions, mostly 7AC Champs (approx. 7,200).

Aeronca ceased all production of light aircraft in 1951, and the Champ design was sold in 1954 to Champion Aircraft.

Champion Aircraft was acquired in 1970 by Bellanca Aircraft which continued production of their Champ-derived Citabria and Decathlon designs. In 1971, Bellanca introduced the 7ACA version of the Champ as a more basic complement to their other designs. Champion Aircraft was acquired in 1970 by Bellanca Aircraft which continued production of their Champ-derived Citabria and Decathlon designs. In 1971, Bellanca introduced the 7ACA version of the Champ as a more basic complement to their other designs, as the least expensive, and lowest-performance, commercially produced light plane on the market at the time.

Only a handful of 7ACA's were built between 1971 and 1972. Bellanca ceased all production in the early 1980s.

American Champion Aircraft Corporation acquired the Champ and related designs in 1989. In 2001, they were rumored to be considering a reintroduction of the Champ design as a 7EC powered by a Jabiru Aircraft engine. While a test version was flown, this combination was not put into production. With the creation of the light-sport aircraft (LSA) category of aircraft in the United States by the FAA, American Champion in late 2007 began producing a revised version of the 7EC powered by the 100 hp Continental O-200-A. The new production aircraft are type certified, but also qualify to be flown by sport pilots in the United States. Although the fuselage and cowling contours are similar to the original-production models, the new aircraft uses the windows, interior, door, and windscreen of the modern Citabria. Fuel capacity is reduced to 18 gal to conserve weight; despite this measure and various others, such as the use of aluminum landing gear legs and bare birch floorboards rather than carpet, the aircraft's payload is inadequate to carry two adults and full fuel simultaneously. The manufacturer is considering various further weight-reduction measures including the use of the lightened Continental O-200D engine previously offered in the Cessna 162 Skycatcher.

Standard-production 7AC, 7BCM (L-16A), 7CCM (L-16B), 7DC, and 7ACA models qualify as U.S. Light Sport Aircraft. Only those specific original-production 7EC airplanes certificated at a 1300 lb gross weight qualify for the LSA category; a standard original-production 7EC is certificated at a gross weight of 1450 lb and does not qualify.

Variants
Various versions of the Champ have been tested and produced since 1944, including military, aerobatic, cropduster, tricycle-gear and (as the Champion 402 Lancer twin-engined variants).

The derivative Citabria designs — models 7ECA, 7GCAA, 7GCBC, and 7KCAB — are discussed in a separate article, as is the twin-engined 402 Lancer.



7AC Champion


Introduced in 1945, the 7AC Champion ("Champ") was the first (and, by far, the most popular) version of the design. It used the Continental A-65-8 engine of 65 hp. (Other 65-hp engines by Lycoming and Franklin were also fitted.) The Champ featured a conventional landing gear configuration, with shock absorption in the main gear provided by oleo struts. Approximately 7,200 were built between 1945 and 1948 -- far outnumbering all other subsequent variants combined, and far outnumbering most rival designs of the period.[citation needed]. Gross weight is 1220 lb and fuel capacity is 13 gal in a single tank.

7BCM, L-16A


Aeronca began building the 7BCM in 1947. This version upgraded the engine to a Continental C85, and featured a "no-bounce" version of the main landing gear. All of the 7BCM production went to the military as model L-16A. These served with the United States Air Force, Army, and National Guard. In 1956, many L-16s were transferred to the United States' Civil Air Patrol. Many L-16As ultimately made their way back into civilian use as 7BCMs. Gross weight and fuel capacity are unchanged from the 7AC.

7CCM, L-16B
An improved version of the L-16, the L-16B/7CCM featured a 90 hp Continental C90-8 engine, an enlarged vertical tail, hydraulic brakes, and a gross weight increased to 1300 lb. A gross weight increase to 1350 lb is allowed when "Long Stroke Oleo Landing Gear" is installed and placard, "Intentional spinning prohibited when baggage carried", is installed on the instrument panel. An additional 5.5 gal fuel tank is used, increasing total fuel capacity to 18.5 gal. Unlike the L-16A not all production went to the USAF. Due to an early cancellation of the production contract some aircraft went directly to the civilian market as 7CCM Champions. The military L-16B featured hydraulic brakes and the "no bounce" landing gear while civilian 7CCM models retained the hydraulic brakes but were fitted with the standard Aeronca oleo landing gear. The L-16A and B featured an enlarged "greenhouse" canopy glazing whereas the civilian 7CCM had the original type windows and headliner. Many USAF and Civil Air Patrol L-16Bs returned to the civil market as 7CCMs after their military service.



7DC
Continental C85 engine. 85 hp similar to the 7AC except the vertical stabilizer is extended forward to accommodate the increase torque from the more powerful engine, and the aircraft was now fitted with a basic electrical system including starter, generator, battery, and radio. Allowable gross weights and fuel capacity are identical to those for the 7CCM.

7EC Traveler
1950 brought the introduction of the Aeronca 7EC, which features a Continental C90 engine of 95 hp, standard long-throw oleo strut main gear, thicker seat cushions, additional interior insulation for noise reduction, an improved heater and electrical system, the addition of a parking brake, and a change in center of gravity for enhanced speed. Advertised empty weight is 890 lb. Standard gross weight is 1450 lb, or 1300 lb with "Lower End Landing Gear Oleo Strut Assembly." Standard fuel capacity is unchanged from the 7DC; an optional 26 gal system was offered, increasing the manufacturer's empty weight by 30 lb. 773 were built.

The last Champ produced at Aeronca was a 7EC, and when Champion reintroduced the Champ in 1955, it was with their version of the 7EC, very little changed from Aeronca's. Champion's version did replace the mechanical brakes with hydraulic. An enhanced version called the Champion DeLuxe Traveler offered a metal propeller with spinner, wheel pants, a steerable tailwheel, and navigation lights.

In late 2007, American Champion introduced a revised version of the 7EC, featuring the Continental O-200-A engine of 100 hp. Differing in a number of ways from earlier 7ECs, this new version in particular replaces the wood-spar wings of the earlier versions with a metal-spar wing, and it uses aluminum gear legs. To fit within the Light Sport requirements, the maximum weight is reduced to 1,320 pounds (599 kilograms).



7FC Tri-Traveler
In 1957, Champion brought out the 7FC, a design sharing many parts, including the engine, with the 7EC; the most significant difference is the tricycle landing gear arrangement with oleo struts on all 3 wheels and extra frame bracing for the nosewheel. Factory standard equipment was comparable to the tailwheel DeLuxe Traveler. The 7FC is 3 mph slower and 90 lb heavier than an equivalent 7EC. Standard gross weight is 1450 lb. 472 were built.

The nose-wheel equipped 7FC has a useful load of 540 lb compared with 630 lb for the conventional (tail-wheel) geared 7EC. Both 1957 models are equipped with a Continental C90-12F 90 hp engine.

7GC Sky Trac
A 7EC with a 140 hp Lycoming O-290-D2B engine and three seats, 171 built. Gross weight is 1650 lb in standard configuration, 1732 lb in seaplane configuration.

7GCA Sky Trac
Agricultural variant of the 7GC with a 150 hp Lycoming O-320-A2B engine, 396 built. Standard gross weight is 1650 lb.

7ACA Champ
In 1971 Bellanca introduced the 7ACA, a modernized version of the design which made it a variant of the Citabria line. The 7ACA is powered by the two-cylinder Franklin 2A engine of 60 hp, a change which required a cowling redesign. The oleo-strut main gear are replaced by steel legs like those used on the later Citabria models, and the rear side windows are squared-off versions, again matching the Citabrias. Gross weight is 1220 lb.

Additional References

 * Aircraft specification no. A-759. Revision 69.  (April 2, 2007.)  Department of Transportation.  Federal Aviation Administration.
 * Taylor, J. H. (ed) (1989) Jane's Encyclopedia of Aviation. Studio Editions: London. p. 28
 * airliners.net
 * Taylor, J. H. (ed) (1989) Jane's Encyclopedia of Aviation. Studio Editions: London. p. 28
 * airliners.net
 * airliners.net