The Evolution of the Challenger

Quad City Aircraft Corporation, manufacturer of the Challenger, has a different philosophy than most other manufacturers. Rather than introducing new models on a regular basis just for marketing hype, they believe that if the basic design is right and the concept of the airplane fulfills an important need, it should be continuously improved and refined to the highest level possible, rather than starting over from scratch with subsequent new, unproved models.

No matter how talented the designer, every new model goes through a troubleshooting process as feedback comes from the experience of owners in the field over the years. If that information is responded to constructively, it will lead to a far superior airplane and a happier customer who is free from the niggling problem solving and trouble shooting that accompanies new models.

What follows is a detailed list of the improvements made to the design since 1983 and the approximate date of the introduction of each modification.

Owners can check the date of manufacture of their Challenger to determine which improvements are incorporated. Note that the Date of Manufacture shown on the Certificate of Registration is usually not the actual date the kit was manufactured by Quad City. In some cases the dates are years apart!

To correctly determine the date of manufacture you must check the serial number (located on top of the square root tube above the cockpit) which shows the order date. Kits are usually manufactured 4 to 16 weeks after order.

For example, assume the serial number is 'CH21095-1405'. 'CH2' means it is a Challenger II (two-seater) with a long wing. '1095' means the plane was ordered in October 1995. '1405' means it is the 1,405th long wing Challenger II made.

Clipped-wings have the letters CW in the serial instead of a hyphen. If there is another letter, an R or a B for example, it indicates that the aircraft was shipped with Dacron sailcloth wing covering instead of Superflite or Stits aircraft fabric. The letter denotes the color: Red, Blue, etc. Single-seaters are identified by eliminating the prefix CH2 before the remainder of the serial number.

Calendar of Improvements to the Challenger

1983 - The KFM powered Challenger single-seater prototype is designed, built and tested and production begins.

1983 - The nose shaft is strengthened by changing from 1 inch X .090 2024 T3 aluminum to 1 inch X .120.

1984 - The Rotax 447 powered Challenger II prototype is designed, built, tested and production begins.

1984 - The KFM engine used on the Challenger single-seaters is dropped in favor of Rotax engines.

1984 - Nylon cores are installed in control sticks at their pivot points, also in 2CT-3 fuselage cross members where the control sticks are attached to the fuselage. This provides a tighter 'feel' as well as preventing wear and play at pivot points.

1984 - A nylon core is installed in rear fuselage boom tube (2FB11) to prevent wear and play in elevator bell crank pivot point.

1984 - Elevator bell crank horns are changed from 2024 T3 aluminum to stainless steel to prevent elongation of holes over time.

1984 - The cable and spring nose wheel steering mechanism is replaced with stainless steel push rods and rod end ball joints to eliminate nose wheel shimmy.

1984 - The FB11 fuselage cross tube is modified and strengthened by double sleeving in 6061 T6 aluminum.

1984 - The nose shaft is further strengthened with a T outer sleeve in Chromoly steel.

1984 - Fabric and Lexan doors are introduced for the single-seat Challenger.

1984 - The leading edge of both stabilizers are strengthened by double sleeving with 6061 T6 aluminum to prevent wear at attach points.

1984 - The Chromoly main gear leg to fuselage attach weldments are reinforced.

1985 - Rotax mufflers were reinforced at Quad City Aircraft with two welded steel straps to prevent muffler cracking.

1985 - CSR2, CSR-4 and CSR-6 ribs are added to provide additional bracing for the 2 FB-2 cockpit rail.

1985 - A stainless steel wrap around exhaust mount was developed to prevent cracking of the Rotax muffler.

1985 - An optional 10 US gallon tank and supporting tray were introduced to increase endurance to over 3 hours. The standard tank was 5 US gallons.

1985 - Main wheel brakes are introduced.

1985 - An additional attach point on aileron bell crank (1 inch lower than previous) for the aileron pushrod is provided to allow the option of adjusting the ailerons for more aggressive response.

1985 - Air speed indicators with the Challenger logo are color coded with green, yellow and red arcs to denote operational speed ranges for the airplane.

1985 - A triangular gusset is installed to strengthen the junction of the FB11 cross tube and the 2FB11 rear fuselage boom tube.

1986 - An additional attach point (1 inch inboard from previous) is provided on the rudder horns to allow the option of adjusting the rudder for more aggressive response.

1986 - Flaperons are introduced as an option that reduce stall speed by 5 mph and provide the function of an in cabin trim system.

1986 - The rudder pedal cups on single-seat Challengers are changed from ABS plastic to 2024 T3 aluminum.

1986 - Octagonal steel washers are introduced to prevent chafing between the brake drum and the wheel that would result in movement of the wheel halves and eventually causing flat tires.

1986 - Two large triangular boxed gussets are added to further strengthen the junction of the FB11 cross tube and the 2FB11 rear fuselage boom tube.

1986 - Hegar V-belt reduction drive ratio is changed from 2.1 to 1 to 2.2 to 1. This larger top pulley and new ratio greatly reduced harmonics, smoothing operation as well as allowing greater fuselage clearance for the propeller.

1986 - The dorsal fin is shortened 1 inch to enhance propeller clearance.

1986 - The standard propeller diameter is increased from 52 inches to 54, providing an increase in the rate and angle of climb.

1986 - An optional winter enclosure comprising a wrap around windshield and pair of removable doors are introduced that permit comfortable cold weather operation of the aircraft with cabin heat as well as open air (convertible) operation in the summer.

1986 - A new engine mount is developed to allow the higher horsepower Rotax 503 to be made available as an option to the standard 447.

1986 - The Hegar 4 V-belt reduction drive system is replaced with an HTD cog belt system which provides the positive engagement of a tooth belt with the vibration dampening advantages of a reinforced rubber belt. The new system also greatly simplifies belt tensioning and eliminates the previous potential problems of V-belt slippage if adjusted too loosely or excessive crankshaft bearing wear if adjusted too tightly.

1987 - The zero porosity Dacron covering used on the fuselage, tail feathers, ailerons and wing tips is replaced with pre sewn socks of Stits certified aircraft fabric.

1987 - The elevator shape is changed from rectangular with a straight trailing edge to one with a curved trailing edge for improved aesthetics.

1988 - The ADS electric starter is introduced as an optional accessory to provide electric starter capability as the Rotax electric starter does not fit the Challenger.

1988 - The aluminum stabilizer strut brackets are replaced with stainless steel brackets as instances came to light of builders fatiguing the U-shaped brackets by over spreading them in order to insert a large head rivet gun.

1988 - The number of stainless steel rivets attaching the inboard aileron hinges is doubled.

1988 - The 503 powered Challenger II Special is introduced as a clipped wing version (26 foot span in US, 28 foot span in Canada) of the two-seater. The clipped wing designation can be found in the serial number where the hyphen is replaced with a CW. Higher cruise and top speeds accompanied with increased roll rates are the primary differences. Initial flight testing includes a 2500 mile cross country flight (with 2 other Challengers) from Moline Illinois to Lakeland, Florida and return.

1988 - The single-seat fabric and Lexan doors are replaced with a full wrap around Lexan enclosure as on the two-seat airplanes.

1988 - The lower engine formers are lowered to provide greater clearance between fuselage and engine to facilitate spark plug access and provide room for a cabin adjustable heater system.

1988 - Stits certified aircraft fabric becomes available as a zero cost option for the wings to provide longer service life and improved appearance over the old style pre-colored Dacron sailcloth wing covers. A Stits rib kit is made available so older style Dacron wings can be updated to use Stits fabric. Later on the Superflite brand of the same fabric comes into use.

1988 - The Dacron pre-colored sailcloth wing covers are modified to incorporate 12 ribs per wing in place of the previous 6.

1988 - Optional streamlined strut and gear fairings become available that reduce the engine off sink rate of the large wing two-seater from 500 ft/min to 330 ft/min greatly enhancing the plane's soaring capability. The streamlined fairings also increase cruise and maximum speeds by 7 miles per hour.

1988 - Stainless steel jury strut attach brackets are introduced to replace the 6061 T6 aluminum brackets when using the streamlined fairings. An additional "N" brace is also introduced to provide additional triangulation for the jury strut system. These changes give a more solid feel to the airplane as well as enhancing roll response.

1988 - A 26 foot span Rotax 447 powered clip wing Special version of the single-seater is introduced.

1989 - Rod end ball joints are introduced in place of clevis forks and pins on the elevator push rods to prevent play developing in the system.

1989 - Brakes are now supplied pre-welded to the axles to simplify assembly.

1989 - An optional smoked glass tinted Lexan windshield and winter enclosure becomes available to enhance appearance, decrease summer cabin temperatures and reduce eye strain in bright conditions.

1989 - The aileron control system geometry is changed to provide lighter stick forces.

1989 - Fiberglass droop wing tips are introduced as a cosmetic option after Challengers so equipped win major awards at Oshkosh and Sun 'N Fun.

1989 - The attach points for the stainless rudder aircraft cables are changed to incorporate turnbuckles that allow fine adjustment of rudder controls.

1989 - The Hirth 2703 single ignition engine is introduced as an alternative option to the Rotax 503.

1990 - The aileron chord is standardized on all Challenger models at 7 1/2 inches. Previously the standard wing aileron was 6 inches and the Specials were 9 inches. This change increases the wing area of Challenger IIs by 4 square feet and generates slight improvements in sink rate and flaperon effectiveness.

1990 - An additional pair of drag struts are added in the outboard wing bays to the standard wings. Compression strut spacing is changed from 4 ft to 3 ft.

1990 - An adjustment system is introduced to simplify brake adjustment.

1990 - The long awaited aircraft version of the Rotax 503 is introduced providing many improvements over the earlier snowmobile derived engine. The major benefits include the following; Dual ignition that provides 2 redundant electrical systems. Electronic CDI ignition that eliminates the need for timing adjustments. A larger crankshaft with improved bearings that greatly increase the engine's overhaul intervals and reliability. A more efficient fuel burn from the 2 spark plugs per cylinder which reduces fuel consumption at cruise from 3.8 gallons per hour to 2.8 gallons per hour and thereby significantly increases range and endurance. A dual ball joint exhaust system isolates the muffler from vibration and eliminates the need for muffler reinforcement by the Challenger factory as well as improving engine breathing. These changes result in a significant improvement in performance (400 to 500 RPM) that increase the standard Challenger II cruise speed to 80 MPH, and maximum speed to 95 MPH as well as increasing the rate and angle of climb.

1990 - Optional Mylar coated wing sails are introduced to increase the service life of the Dacron sailcloth wing option.

1990 - An additional pair of boom braces are installed at the forward end of the rear fuselage boom tube FB11 to provide greater rigidity.

1990 - A redesigned belt tensioning system is introduced for the Hegar drive eliminating the necessity of a drilled shaft and simplifying adjustment. A stainless steel collar provides redundancy that ensures belt tension even if the securing bolt is insufficiently tightened.

1991 - An additional lower inboard wing rib is introduced to prevent bowing from over shrinking the underside wing fabric.

1991 - The Hirth 2703 dual electronic ignition engine is introduced.

1991 - An optional fiberglass pointed nose fairing is introduced to further streamline the airplane and enhance its appearance.

1991 - A new optional electric start system is introduced eliminating the maintenance previously required with the older ADS starter.

1992 - An optional 3 piece fiberglass mid-wing gap cover is introduced to better fair the junction of the windshield with the wing and reduce drag at the propeller hub as well as enhance appearance.

1992 - The wing tip bow material is changed from 3/4 inch .049 to 7/8 .058 6061 T6 aluminum.

1992 - A new design of wheel pants is introduced to enhance aerodynamics and appearance.

1993 - A new fiberglass pointed nose option is introduced for single-seaters.

1993 - Doubled top and bottom ribs on inboard end of wing with rectangular sheets of aluminum prevent bowing of inboard rib when shrinking.

1993 - A top to bottom rib is installed between inboard wing ribs.

1995 - New 2.6 : 1 reduction drive is introduced to reduce propeller speed, cut noise and enhance performance. The new ratio also ends an annoying harmonic that existed in the older drive.

1995 - New 60 inch diameter propeller introduced with new drive. Greater propeller efficiency increases cruise speed by 10 mph and increases climb by 15%.

1995 - For float users, Puddlejumper Floats Inc. Introduces a new steerable, retractable nose gear for their amphibious floats that is proprietary to the Challenger.

1995 - The inboard aileron end ribs are relocated 10 inches out from the old position.

1996 - The wing span of clip wing Challenger II Specials shipped to Canada is reduced from 28 to 26 feet to be consistent with clips shipped around the world. This results in slightly higher speeds and roll rates. The change was enabled by amendments to the Canadian Air Regulations to remove the wing loading limits for ultralights.

1996 - In November of '96 Quad City Aircraft shipped their 2000th Challenger. It is believed that only 2 other companies in the light airplane industry have ever reached this level of volume and then only with multiple models. Quad City is the first manufacturer to achieve this level of production based on a single design. It is also the only company to achieve this level with stable ownership and management throughout and therefore uninterrupted service and support of all customers.

1997 - An attractive pair of fiberglass wing tips is introduced. The new tips extend just 6 inches beyond the ends of the spars (versus 18 inches for the previous tips) thus reducing the wing span by 2 feet. They increase cruise and top speeds (with resulting gains in economy) while their shape allows the airplane to continue to enjoy very low stall speeds. These tips attach in such a way as to greatly stiffen the outer portion of the wing. This in turn gives the outer ends of the ailerons (the most effective portion) a better bite and in so doing increases the roll rate, particularly with the reduced span.

1997 - Axle weldments are redesigned to a two part system to increase strength and to eliminate the need of an axle spacer when mounting wheelpants.

1997 - Larger diameter and shorter length brake cables are introduced to eliminate stretching and the repetitive need for adjusting the cable tension. A larger brake handle is also introduced to make brake actuation easier and more effective.

1998 - 2 piece seat cushions are replaced with a one piece design to avoid the problem of the rear seat back cushion being blown out of the plane (and sometimes going through the prop) while flying solo with the doors off. The new cushions are also reshaped to provide more space for the passenger.

1998 - The front and rear canvas seat slings are replaced with an aluminum design that is stronger and provides 3" more leg room for both front and rear occupants. As well, the down tubes forming the back of the front seat are closer together so the passenger has significantly more width for their legs. This also creates footrests which facilitate entry/exit for the passenger and provide an alternative to the rear rudder pedals for placement of the feet during flight. The seat bottoms are hinged for easier access and inspection of the elevator pushrods.

1998 - A hinged aluminum access panel to the fuel tank replaces the earlier canvas version.

1998 - New upper fuselage formers are introduce to ensure adequate clearance between fuselage fabric and the aileron control cables.

1998 - The ailerons are shortened at the inboard end in order to reduce adverse yaw as well as to clean up airflow to the engine and propeller.

1998 - An aluminum firewall is added to the fuselage down tubes in front of the engine.

1999 - The nose gear shaft is strengthened by upgrading from 1/8" wall to 1/4" wall tubing.

2000 - The windshield and enclosure are upgraded from .040" Lexan to .060" for both tinted and clear versions.

2002 - The braking system is further improved by changing to larger more powerful shoes and self-centering "floating" drums.

2004 - The powerful 65 hp Rotax 582 is approved for Challenger II aircraft with factory specified motor mount, exhaust mount, cooling system, reduction drive, prop and optional oil injection. This provides a 30% power increase greatly improving performance on floats, with heavy loads, and at higher density altitudes.

2005 - The manufacturer specified gross weight is increased to 960 pounds for Challenger II long wing aircraft kits manufactured after mid 1990, when changes to the long wing structure were implemented, as well as for all Challenger II Special clip wing aircraft. This gives owners a great deal more leeway for options, accessories and floats.  Click here for details on how to determine if the increased 960 lb gross weight is applicable to any previously manufactured Challenger.