Denny Kitfox

Denny Kitfox

Infobox Aircraft
name = Kitfox

caption = Denney Kitfox Mark II
type = kit aircraft
national origin = USA
manufacturer = Denney Aircraft, SkyStar Aircraft
designer = Dan Denney
first flight = November 1984
introduction =
retired =
status =
primary user =
more users =
produced =
number built =
program cost =
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developed from =
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The Denny Kitfox was a series of small personal airplane kit with folding wings, originally designed, built and, manufactured by Dan Denney. The Kitfox is unique in that it was one of the first designs to make popular a quickly folding wing that greatly eased transportation and storage. The aircraft is experimental (not FAA certified) and was originally designed to accommodate a Rotax engine (also experimental) but can commonly be found with a variety or other engines. The large appeal of the aircraft was in large part due to the fact it could be built by any handyman in a two car garage and then towed to the airport with the wings folded. The design allowed for easy conversion to floats or skis. At one point Kitfox was the largest small plane manufacturer in the world producing more aircraft a month than Cessna, Beechcraft, and Piper combined.fact|date=September 2008


Flown in November 1984 from their Boise, Idaho factory, the first Kitfox was a lightweight, two-seat short take off and landing STOL aircraft, the Model 1. Similar in concept to the famous Piper J-3 Cub, the aircraft was a lightweight, two-place sport aircraft with good STOL performance, enabling it to fly from short and unimproved airfields. The Kitfox features folding wings and is easily trailered, allowing owners to share hangar space or keep their Kitfox's at home in a single car garage. Six Model 1 Kitfox's were delivered that first year. Six Model 1 Kitfoxes were delivered the first year, after which the Kitfox range was expanded from the Model 1 to improved versions known as Models 2, 3, 4, and Classic 4. The Kitfox for several years held the record for shortest takeoff roll in a fixed wing aircraft (convert|21|ft|m|1) which took place at the national Sun 'n Fun Fun event in Florida in 1989.fact|date=September 2008

In June 1992, SkyStar Aircraft corporation purchased the rights to produce the Kitfox kit from Denney Aerocraft, and began development of a completely new Kitfox, the Series 5. This larger aircraft was designed to fit the needs of pilots who wanted a recreational aircraft that combined the best attributes of the Kitfox with greater useful loads, certified engines, increased cabin space, and larger cargo capacity. The Series 5, which offered both a taildragger (the Outback/Safari) and a tri-gear (the Vixen/Voyager) configuration, answered these requests and became one of the most successful introductions in the history of the kit plane industry. The changes made after the 1992 purchase are largely credited with the subsequent decline in popularity and performance of the aircraft, which ultimately contributed to the later bankruptcy of the company.

In January 2000, an employee group acquired SkyStar Aircraft, and a new chapter began for the SkyStar team. SkyStar announced the new Kitfox Series 6, an aircraft that incorporated all of the best features of all versions of the Series 5. Later that year, the company also introduced the Kitfox Lite Squared, a version of the Kitfox Classic 4, as a two seat companion to the single seat Kitfox Lite. The Series 5 evolved into the Series 6, and then the Series 7. In October 2005, Skystar encountered financial difficulties and ceased operations.

In 2002, SkyStar introduced the new, high performance Kitfox Series 7, with cruise speeds of up to convert|160|mph|km/h|0, and a service ceiling above convert|25000|ft|m|0. The new Series 7 was better adapted to the Sport Plane regulation than was the Lite Squared, and was therefore selected as SkyStar's entrant into the Sport Plane market. As understanding of the proposed Sport Plane rules increased, it became obvious that the specially-packaged version of the Kitfox Series 7, known as the Kitfox Sport, would not be needed, and that all three Kitfox airframes then in production (Lite, Classic 4, and Series 7) met the Sport Plane definition.

In late 2005, SkyStar Aircraft filed for bankruptcy. In early 2006, Kitfox Aircraft LLC acquired the production rights, tooling, patents, and trademarks for the Kitfox aircraft. The aircraft is now back in production. In April 2006, the assets of Skystar were acquired by Kitfox Aircraft LLC, a newly formed organization operated by John and Debra McBean. The McBean's own and operate Sportplane LLC, a Kitfox specialty supply firm they founded after John's departure from Skystar in 2003.

Kitfox model history

Model 1 (1984)

Serial #1-257 The Kitfox Model 1 introduced the nostalgic “bump” cowl that has become the signature of the Kitfox. This cowl design was originally intended to accommodate a small radial engine, but the engine intended for the Kitfox never matured. The “round engine” look was retained, and remains popular today. The compact Model 1 had an empty weight of only 425 lb (193 kg), and a gross weight of 850 lb (386 kg). The Rotax 532 was the engine of choice, although other two-stroke engines have been used. From a flying standpoint, the Kitfox Model 1 would be called an ultralight by today’s standards. It is a very simple, basic aircraft that is light weight and relatively high powered (usually 65 HP). The interior can best be described as “cozy,” and the aircraft was usually built without dual brakes. The Model 1 accelerates rapidly and has light ailerons. There is a good deal of adverse yaw coupled with a neutral yaw axis. The adverse yaw is easily taken care of with rudder, but the rudder feel is different than most contemporary aircraft. Basically, by pushing the rudder to yaw the plane, it will stay yawed. The pilot may have to physically move the rudder to bring the nose back to the center. It takes time to adapt to this characteristic, but it is easily learned. The flaperons may be moved as flaps to affect pitch trim and lower the stall speed. Lowering the flaperons to more than 2/3 of their full travel will result in up to a 50% reduction in roll rate. Takeoffs and landings are quite normal for a tailwheel aircraft and easier than most. The nose fuel tank keeps most of the mass (center of gravity) right along the centerline, and directional control is not a major challenge.
* Gross weight 850 lb
* Average cruise speed 75 mph
* Stall Speed 36 mph
* Average empty weight 426 lb
* Average useful load 424 lb
* Max speed (Vne) 100 mph
* Cabin width 36 in
* Wing span 32 ft
* Length (wings folded) 21 ft
* Width (wings folded) 7 ft 10 in
* Height 67 in

Model 2 (1989)

Serial #258-748 The larger, wider Kitfox Model 2 was introduced in 1989. This “beefier” Kitfox allowed for greater useful loads and more room in the cabin. The Model 2 featured a larger vertical tail area and the new Rotax 582 engine option. The gross weight was increased to 950 lb (431 kg). The airfoil and control systems remained the same as the Model 1, but spars were strengthened to accommodate the higher gross weight. Flying-wise, the Kitfox Model 2 is quite similar to the Model 1. The larger tail surface helped some with the yaw issues, but was somewhat offset by larger engines and the introduction of wing tanks. Like the Model 1, the Model 2 is yaw neutral and needs to have the nose “placed” where it needs to be. Flaperon use and characteristics are virtually identical to the Model 1. Dual brakes were available for late Model 2 aircraft, and many earlier Model 2 aircraft have had dual brakes installed. Ground handling is similar to the Model 1, but the increase in gross weight, therefore greater mass, does cause one to pay a bit more attention to the landing rollout.
* Gross weight 950 lb
* verage cruise speed 85 mph
* Stall Speed 36 mph
* Average empty weight 426 lbs
* Average useful load 524 lbs
* Max speed (Vne) 100 mph
* Cabin width 39.5 in
* Wing span 32 ft
* Length (wings folded) 21 ft 1 in
* Width (wings folded) 7 ft 10 in
* Height 67 in

Model 3 (1990)

Serial #749-1215

The Kitfox Model 3 featured structural changes that were designed to improve flight characteristics and provide a better platform for more powerful engines like the new 80 HP Rotax 912. A larger vertical stabilizer and rudder were added, as well as larger, stronger lift struts and spar carry through tubes in the fuselage. The gross weight was increased to 1050 lb(476 kg), but the empty weight only went up by a few pounds. This was the last Kitfox to use the original airfoil and flight control system introduced on the Model 1.

The Model 3 was the first major attempt to aggressively deal with the yaw control issue. This does not refer to yaw instability, but a neutral yaw condition. In other words, it was desired to have the aircraft return to straight flight after pressing a rudder without having the pilot move it back with their feet. Much of this objective was achieved by increasing the size of the vertical fin. The flaperon system is identical to the Model 1 and Model 2, with very similar handling characteristics. Again, the higher gross weight requires one to practice at least average tail wheel skills.
* Gross weight 1050 lb
* Average cruise speed 85 mph
* Stall Speed 37 mph
* Average empty weight 460 lb
* Average useful load 590 lb
* Max speed (Vne) 100 mph
* Cabin width 39.5 in
* Wing span 32 ft
* Length (wings folded) 21 ft 1 in
* Width (wings folded) 7 ft 10 in
* Height 67 in

Model 4-1050

Serial #1400-1722

Introduced at Oshkosh in 1991, the Kitfox Model 4 was a completely new aircraft featuring innovations that enhanced the STOL abilities, improved flight handling and stability, and increased top speed by 10 to 15%. The Model 4 featured a new higher speed, laminar flow airfoil, new flaperon design, metal flaperon attach brackets, and a brand new 2:1 differential aileron control system that allows much improved control at full flaps. The gross weight of the Kitfox Model 4-1050 was the same as the Model 3, 1,050 lb (476 kg). The Model 4 is an ideal platform for the Rotax 912 series of engines but is equally suitable for two-stroke engines.

From a flying standpoint, the Kitfox Model 4-1050 was a genuine attempt to make the Kitfox handle like a contemporary, certified aircraft, without losing the heritage of agility. It worked. The new airfoil added speed and performance. The flaperon airfoil, area, placement and movement ratios were changed significantly. For the first time, the flaperon moving up traveled twice as far as the flaperon moving down. This is similar to a Piper Cherokee. Rudder coordination was made much easier. The flaperons continued to be used for climb and cruise pitch trim, and back pressure is required to maintain approach speed. While reduction of roll rate was not as pronounced, the use of full flaperons did reduce the roll by up to 30% and increased the stick loads. The vertical fin area remained the same as the Model 3, once again a bit small for the larger engines now being installed. While yaw stability was no longer neutral, it was not aggressively positive. It would take one more iteration to get yaw stability to a more contemporary feel.

Model 4-1200 (Classic IV)

Serial #1723-

The Kitfox Model 4-1200, currently marketed under the name of the Kitfox Classic 4, is the final evolution of the original Denney Aerocraft Kitfox design that began in 1984. One of the most successful kits on the market today, the Classic 4 kit has been sold continuously since late 1991. The Classic 4 has heavier lift struts and gear legs, as well as beefed up carry through tubes in the fuselage, to allow for a higher gross weight than the earlier Model 4 kits. The height of the vertical stabilizer and rudder was increased by convert|10|in|cm|0, and the rudder depth was increased by 2 inches to allow for improved handling. The Classic 4 is also available in a short wing Speedster configuration for those wishing more speed and a higher roll rate. In 1994, a light weight version of the Classic 4 was introduced with a Rotax 503 as the standard power plant. This aircraft, known as the Kitfox XL, qualified as an ultralight trainer, but did not gain market popularity. In 2001, an upgraded version of the Kitfox XL was introduced as the Kitfox Lite Squared and met with instantaneous market success. The Kitfox Classic 4 remains suitable for both the two-stroke and four-stroke Rotax 912 engine series. Many other engines have been adapted to the Kitfox Classic 4. Not only is the Kitfox Model 4 (Classic 4, Speedster, Lite Squared) the final evolution of the original Denney Aerocraft concept in terms of structure and engineering, but it is the best flying of all the previous versions. The vertical surfaces were increased significantly, resulting in excellent, positive, yaw stability. The Speedster version of the Model 4 added aerodynamic enhancements to the empennage, including an electric trim tab. Speedster modifications can be used on any Model 4 variant. Handling is smooth and crisp. While rudder coordination is needed, it is much closer to what most pilots encounter in today’s modern training aircraft.

The higher gross weight and larger wing fuel tanks cause one to pay attention on landing rollout, but the much larger vertical tail surface gives the pilot all the control power needed, and then some. The available electric pitch trim allows the Model 4 (in all its variations) to be trimmed for hands off flight in almost all normally anticipated flight attitudes. Many Model 4 aircraft were equipped with the 4-cylinder, 4-stroke, Rotax 912 that produces 80 HP. Model 4 variants are now turning up with the 100 HP Rotax 912S, resulting in power loadings that are better than the original, light weight, Model 1. The pilot should be prepared for an aircraft that is ready to fly before them. In 2001, the Classic 4 was packaged as the Lite Squared and introduced into the ultra light community as a two place, ultra light trainer. This packaging resulted in the Classic 4/Lite Squared being adapted to tri-gear in addition to the familiar tail wheel configuration.

eries 5 (Safari, Vixen, Outback, Voyager)

In 1994, SkyStar aircraft was faced with an increasing demand to produce a significantly larger version of the Kitfox that would be able to utilize contemporary certified engines (Continental and Lycoming) in addition to the Rotax 912 engines. The answerer to this demand was the entirely new Kitfox Series 5. While appearing very similar to the Kitfox Classic 4, it is, in fact, a completely new design. The Kitfox Series 5 introduced a new marketing approach in which different variations of the Series 5 were given names. The tailwheel version became known as the Safari, and the tri-gear version (the first production tri-gear aircraft based on the Kitfox design) was named the Vixen. The Vixen utilized a swept tail, a cosmetic change that did not affect performance.

Originally introduced with a gross weight of 1400 lb (635 kg), the gross weight was increased to 1550 lb (703 kg) in mid-1995. The handling characteristics became much more like those of contemporary certified aircraft, but lost none of the agility that had become a Kitfox trademark. As with all Kitfox aircraft, the folding wing feature was retained. In 1998, the name of the Safari was changed to the Outback, and the Vixen became the Voyager, but the basic features remained the same. A short wing version of the Series 5 was also sold, and it was known as the Series 5 Speedster. Although heavier and larger, the Series 5 is an aerodynamically cleaner design than the Classic 4 and cruises at a higher speed.

The Series 5, and variations thereof, are a delight to fly. Refinements to the vertical tail surfaces and a new horizontal stabilizer with trim enhanced the pitch feel. The Series 5 has a “smoother” feel than the quick reacting Model 4, but retains the overall agility. Yaw stability is positive and good. The greater weight of the 1550 lb (703 kg) aircraft, coupled with the greater mass of Continental and Lycoming engines, causes the Series 5 to feel very much like a larger, heavier, certified aircraft. This is not a surprise, as the Series 5, along with its tooling, was specifically designed to meet Primary Aircraft certifications standards. The tri-gear version of the Series 5 (Vixen/Voyager) is a contemporary nose gear aircraft in all respects. The use of differential braking to steer the tri-gear aircraft may take some practice, but offers unparalleled ground maneuverability. The larger engine choices result in a larger cowling and limited forward visibility during ground operation of the tailwheel version of the Series 5. Good tailwheel proficiency is suggested before a pilot's first flight of the “limited view” Series 5. Cruise flight in the Series 5 is nose low, resulting in very good in-flight visibility.

eries 6

SkyStar’s new management team introduced the Kitfox Series 6 in 2000 as the latest refinement of the Kitfox line of aircraft. The multiple versions of the Series 5 Kitfox were all rolled into a single aircraft that possessed the most versatile features of all the Kitfox's. The Kitfox Series 6 has a useful load of up to 800 lb (363 kg) and a range of over convert|700|mi|km|0, coupled with cruising speeds of over 120 mph (193 km/h). The factory’s Series 6 actually averaged 137 mph (220 km/h) in the Sun ‘n Fun 100 Air Race in 2001, and that was with two folks on board, a bunch of cameras and crew meals! The Series 6 could be configured as either a tri-gear or tailwheel aircraft, and can be converted to either version after assembly is completed. Assembly times were significantly reduced, and the Series 6 accommodates more engine types than any other Kitfox. The look, feel and flight characteristics of the Kitfox Series 6 are like those of the most sophisticated, certified aircraft, but none of the Kitfox adventure has been sacrificed.

All of the good flying qualities inherent to the Kitfox Series 5 are present in the Kitfox Series 6. The Series 6 has a heavy-duty landing gear system that improves soft and rough field ground handling. The Series 6 no longer used the bungee/tube landing gear that was standard on the Series 5, resulting in a more easily controlled aircraft during rollout after a tailwheel landing. Like all Kitfox's, the Series 6 retains the ability to perform awesome forward slips and is an ideal aircraft for short field operations. The Kitfox Series 6 has a refined flap system that allows the selection of two optimum flap positions. The first notch is used for takeoff and approach. while the second notch is generally reserved for landing. The tri-gear version of the Series 6 is very well balanced, and smooth takeoff and landing rotations are effortless.

eries 7

The Kitfox Series 7 introduces a variety of both major and subtle changes in the Kitfox history of ongoing product development. Most noteworthy is a variety of engine system enhancements that have resulted in an aircraft that can cruise at over 150 mph, fly 700 miles non-stop, and heft a useful load of 700 lb (318 kg). Through use of the remarkable Rotax 914, turbo-charged engine, the Kitfox Series 7 has a service ceiling of convert|25000|ft|m|-2, meaning it can operate from any public use airport in the United States, without concern over runway length, field elevation or air temperature.

Flight control improvements have lowered the landing speed and reduced aileron induced yaw. The larger elevator and new manual trim system strengthen pitch authority and stability. The entire Rotax engine installation has been greatly simplified, resulting in a significant reduction in assembly time. This new installation also results in much improved windshield weatherproofing. Like the Kitfox Series 6, which has been replaced by the Series 7, convertible landing gear, folding wings, and many custom features are standard.

While many of the Series 7 performance improvements are achieved with the Rotax 914, Continental and Lycoming engines, in addition to the popular Rotax 912S, remain very popular engine choices. Most Series 7 improvements can be retrofitted to the Kitfox Series 5 and 6.

Engine alternative

Jabiru Aircraft produces mounting kits for this airframe to allow use of their boxer six engine.

External links

* [ Kitfox, LLC] , current owners of the Kitfox brand
* [ Kitfox Videos and Information.]
* [ Matronics Kitfox Forum]

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