Pterodactyl History

Updated 02 September 2005

By Adam Hunt

 

From the time when they first entered the market in 1978 the Pterodactyl ultralights generated a great deal of enthusiasm and devotion amongst ultralighters. This devotion has lasted well into the 21st Century. In their heyday during the ultralight revolution of the late 1970s and early 1980s they were the standard to which all other ultralights were compared and were flown on many remarkable long flights. Over time the Pterodactyl has become an aviation legend.

The history of the Pterodactyl family of aircraft started off with the design of the Manta Fledge rigid wing hang glider. Designed by the famous designer of the Super Floater glider and later the Drifter ultralight, Klaus Hill, the Fledge hang glider was the high performance hang glider of its time, the mid 1970s. The design evolved through the Fledge I, II and finally the III, with several sub-models designated with letters after the roman numerals. The hang glider relied on its wing sweep for yaw stability and weight shift for pitch control. Unlike flex wing hang gliders, it used tip rudders for roll control, operated by control bar-mounted sliders.

Pterodactyl designer Jack McCornack selected the Manta Fledge IIB wing for his powered hang glider project in 1977. He figured that the wing had lots of growth potential, along with a good speed range and pleasant handling characteristics. McCornack designed a completely new hang cage, engine mounting and undercarriage for the aircraft. Control for the flying wing design was the same as the hang glider – weight shift for pitch control and twist grip tip rudder control for roll. Engine controls consisted of a mouth throttle, as both hands were used for the individual twist grips. McCornack called the aircraft the Pterodactyl Pfledge (also known as a Fledgling and even as a Fledge) and it first flew in 1977. A direct drive Xenoah two stroke engine putting out about 16 hp and swinging a 36-inch prop supplied the power.

pFledge

The original Pfledge was first shown at the Gilroy, California fly-in in 1978. Two Pfledges were actually flown into the desert ultralight gathering. This was an unusual feat in those days when most designs were trucked everywhere and only flown in ideal circumstances, if at all. It was at that fly-in that current Pterodactyl parts and kit supplier Dave Froble met Jack McCornack and decided to buy a Pterodactyl Pfledge. Froble soon became a dealer and started his life-long attachment to the design.

After the Pfledge came the Pfledge X, essentially an improved prototype with a Xenoah 242 powerplant of 16 hp at 5800 rpm. Then a few production types emerged from McCornack’s new company, Pterodactyl Limited. In 1979 McCornack and his flying partner Keith Nicely flew two Pfledges from the factory at Monterey, California to Oshkosh, Wisconsin, for the big EAA fly-in. Initially they started out with ground support but quickly left the truck behind as they raced eastward.

They made a big stir in Oshkosh that year – it is still referred to as “the year that ultralights really caught on”. At Oshkosh the editor of the Mother Earth News, an ecological publication, challenged the pair to fly on to Kitty Hawk NC on pure ethanol and offered to buy the alcohol to do it. Never one to turn down gas money McCornack said “yes” and the two completed the flight to North Carolina, requiring just some mixture adjustments to the engines to run on the alcohol fuel. The seven-week trip was perhaps the longest ultralight flight of its day. It took seven weeks because the two took their time on the flight. McCornack was quoted as saying “If Keith had been able to get another week off it would have been eight weeks.” The flight put Pterodactyl on the map, in a time when dozens of new manufacturers were springing up weekly in the rapidly growing ultralight market. A revolution in aviation was starting. The article published by Mother Earth News about this trip, written by Jack McCornack, can be found on the Mother Earth News website. The 1979 model Pfledge retailed for $2750 when it was introduced.

The production version of the Pfledge that McCornack and Nicely flew to Oshkosh was known as the Pfledge OR (Oshkosh Replica) and was powered by a German-made Sachs SA-340 direct drive engine of 336 cc displacement. It originally sold for $3500 in 1980. Some other early Pfledges were powered by a 136 cc Chrysler engine that put out about 10 hp.

The next version was the Pfledge 430D, powered by a Cuyuna 430D engine, a powerplant that McCornack helped design for the aircraft market and that Pterodactyl marketed directly as their product. The Cuyuna 430D was a two cylinder, two stroke engine of 429 cc displacement that put out 30 hp and weighed 64 lbs. The “D” designation indicated direct drive. The initial price of the 430D was $2800. The price of the Pfledge 430D was $3600 in 1980.

 

McCornack and Nicely’s 1979 Oshkosh flight was probably the second transcontinental flight by Pfledge. A few weeks earlier John D. (Jack) Peterson, Jr. flew his Pfledge from Long Beach, California to Hilton Head, South Carolina in 29 days between July 9th – August 6th 1979. He covered the 3,200 mile distance in 120-mile legs with ground support provided by Dan White, a schoolteacher from Santa Cruz, California. This was the first time that an ultralight had been flown coast to coast. Peterson’s Fledgling is now in a place of honour in the Smithsonian Museum’s Udvar-Hazy Centre.

In early 1980 the Pterodactyl factory moved 30 miles from Monterey to a location at Watsonville, California. The new location was owned by the Monterey Bay Academy, a private co-ed high school campus run by the Seventh Day Adventist Church. The main attractions for Pterodactyl to re-locate there were the large manufacturing space available and the school’s own 2200-foot runway.

Pilots who learned to fly on hang gliders were comfortable with the weight shift pitch control on the early flying wing Pterodactyl models, but pilots coming to ultralights from other parts of aviation were less so. McCornack started work on aerodynamic pitch control in 1979. The first effort was a rear-mounted elevator design called the NFL for “Not Foot Launchable”. It wasn’t a great success, although a few production versions were shipped. The NFL (pronounced “Niffle”) was not foot-launchable because of balance considerations due to the position of the elevator in the back. Prior to the introduction of FAR Part 103 in 1982 it was at least a paper requirement that US ultralights must be capable of being foot-launched if they were to avoid having to be registered as amateur-builts and the pilot licenced. Putting the tail in the front worked much better and retained nominal foot-launch capability. The canard-equipped design first flew in 1980 as well. It retained the direct drive Cuyuna 430D engine and carried the name Ptraveler.

The Ptraveler was an instant success. The name, not only satisfied McCornack’s obsession with the silent letter “P”, but also tried to subtly tell buyers that this aircraft was not just for local messing about the patch. McCornack always believed that ultralights could be used for real cross country trips and he spent many years showing just what was possible with his designs. The generous lift capacity and the large inside-wing storage that the zippered Dacron wing afforded made it possible to actually carry needed items cross country, like tents and sleeping bags. The introductory price of the Ptraveler was $3900 in 1981.

Improvements quickly followed and by 1981 the Ptraveler had traded in its direct drive Cuyuna 430D engine for a 2:1 belt reduction drive Cuyuna 430R. This allowed it to turn a 54-inch prop and reduced the noise of the earlier versions. The new version carried the name “Ascender”. The original intention was to name the new model “Ptomcat”, but another manufacturer had taken the name “Tomcat”. It was fortuitous, as the name “Ascender” came to be a legend in ultralight flying over time. Ironically the other “Tomcat” was a problem aircraft with serious design deficiencies. That name has come to refer to a “dud” aircraft in ultralight circles (Although not in the US Navy where they fly a completely different aircraft with the same name). The first Ascender carried a price tag of $4200 in 1981. To put that price in perspective, that was about 1/10 of the cost of a new, well-equipped Cessna 152 that same year.

The Ascender II quickly followed with more evolutionary refinements – fiberglass spring rod main landing gear was introduced to replace the aluminum gear, along with moving the throttle from the hang cage upright struts to the left side of the hang cage. An improved muffler made the Ascender II quieter yet.

Ascenders were adapted for many specialized purposes. They were used for crop spraying and even an atmospheric research project at Colorado State University. The one-of-a kind Ascender equipped for that atmospheric sounding mission was named the Pterodactyl Psounder.

Work was started at this time on the Pterodactyl Ptug, a hang glider tow plane design. The pusher engine and lack of a tail made the design work interesting. It used a bridle design that fit around the prop, with the towline attachment behind the prop. It worked very well and even today Ptugs out-pull and out-climb other purpose-designed hang glider tugs.

Early 1982 saw the introduction of the Ascender II+. This model had a wider, 20 ½” hang cage (compared to 15 ¾” wide hang cage on all the earlier models), stronger upright struts and a stronger wing with 1 ¾” inch spars of 0.049” thickness (the earlier models used 1 ½” spars of 0.049” thickness) and heavier 1/8” outer bottom cables. It was designed to lift big pilots. The price of an Ascender II+ in 1983 was $5260.

By the late summer of 1982 the two-seater Ascender II+2 was flying and ready for the market. This was simply an Ascender II+ airframe with a second hang cage bolted onto the right side. The right seat pilot had a throttle mounted on the right hang tube linked to the left seat throttle through a push-pull cable arrangement. Both pilots shared the central side stick. The II+2 flew with the same 34 hp Cuyuna 430R engine as all other Ascenders at that time. The II+2 was designed specifically for two roles. The first was dual flight training, forever ending the days of ultralight pilots learning to fly alone in a big field by reading a book. The second role was two-place touring and fly camping. Many two seaters were produced along with many kits for the second seat. The second seat was removable in 10 minutes, converting the aircraft back to a single seater. The first Pterodactyl two seater was actually flown in the summer of 1980 and it was often unofficially referred to at that time as a “Double ‘Dactyl”. The original intention was to market it under the name “Ptoucan” (as in “Toucan fly together”), but once again another manufacturer had taken that name. For a while it was known as the “Ptrainer”, but the name “Ascender II+2” was eventually used. This was probably driven by the fact that the aircraft was convertible back to a single seater Ascender II+ so quickly.

The two seater Ascender II+2 was delayed in development for two years from 1980 to 1982, so that the new FARs governing ultralights could come into being. The FAA was still developing the new rules for ultralights and it wasn’t clear whether two seaters would be included as ultralights or not. When FAR Part 103 appeared in 1982 it defined ultralights as single seaters only and the two-seat II+2 was relegated to the amateur-built experimental category in the USA. Later on it qualified as a FAR Part 103 exemption trainer, when the exemptions were made available. The II+2 did qualify as an ultralight or microlight in many other countries including Canada. The 1983 US price of a Cuyuna 430R powered Ascender II+2 was $5560.

As mentioned, McCornack had always designed his aircraft for real traveling and especially for “fly-camping”, with lots of in-wing stowage for tents and sleeping bags. Pterodactyl actually marketed a small dome tent specifically for fly camping, under the name Ptent, of course. Retail price of the two-man Ptent in 1980 was $135.

As soon as the bugs were out of the prototype two-seater, McCornack invited Robin Sclair, a journalist with the Ultralight Flyer newspaper, to fly with him to Mexico. They were gone for a week, from 14-21 October 1982, covering 1025 miles round trip. The pair flew down the interior of California’s desert country, camping at night, with every second night in small motels along the way. The flight received lots of coverage in the ultralight press and sales did well as a result.

The final Pterodactyl production model based on the original Manta Fledge IIB wing was the Ptiger, introduced around late 1982. This was an Ascender with the wings clipped from the Ascender’s 33 feet to 29 feet and sporting a fiberglass cockpit enclosure. It was capable of 75 mph on the same 430R engine and really exceeded the US FAR Part 103 ultralight rules by quite a margin. Most Ptigers were registered as amateur-built experimental and carried “N” numbers, although production numbers were small.

The last aircraft developed by Pterodactyl Limited was the Light Flyer. This was based, not on the Manta Fledge IIB wing of all the previous Pterodactyl designs, but on the Easy Riser biplane hang glider wing. The Light Flyer was intended to be a nostalgic tribute to the 1903 Wright Flyer (hence the name), but with some practical refinements, such as tricycle landing gear replacing the Wright Flyer’s skid gear. The Light Flyer achieved only very limited production status in 1984 and only about 5 were sold. The price in 1984 was $5400. Reportedly the aircraft flew well.

From the early days of Pterodactyl Limited several after-market suppliers saw the opportunity to sell improvements to the Pterodactyls. Pterodactyl eventually incorporated many of these modifications as factory-standard equipment into their later models. Yarnell Techtonics introduced a welded steel steerable nose gear and a hang tube mounted throttle quadrant. That throttle quadrant later became standard equipment with the introduction of the Ascender II, while the steel nose gear did not, although many Pterodactyl owners installed them. The steel nose gear sold for $195 while the throttle quadrant was $35 in 1980. Yarnell also offered skis for the Pterodactyls for $175 in 1981, although it is not known how many brave winter flyers installed and used them! Mike Stratman introduced an aluminum steerable nosegear and even a nose gear bicycle-style brake for the aircraft. The Stratman steerable nose gear sold for $85 while the brake set was $45 in 1981. The Stratman nose gear became the basis for the current DFE Ultralights factory-standard steerable nose gear. Another company produced a fibreglass spring-rod style main landing gear to replace the troublesome factory standard aluminum gear. The fibreglass spring rod suspension also became a standard-factory item starting with the Ascender II. Sierra Floats of Lake Tahoe California produced a flat-bottomed set of fibreglass floats that featured solid foam cores for the Pterodactyls. In 1984 they sold for $1000, plus $300 for the mounting hardware. Ballistic Recovery Systems (BRS) designed an installation for the Pterodactyl and recorded the very first BRS “save” on a Pterodactyl in August 1983.

Some production Ascenders were equipped with wing-mounted spoilers for roll control as an option, the spoilers being actuated by foot pedals. This gave true three-axis control and some degree of improved crosswind capability to the design, at the cost of weight, cost, complexity, drag and set-up time. Pterodactyl also experimented with flaps at one time for the Ascender, although these were never marketed.

As evolutionary changes were made to the basic design over the years, Pterodactyl Limited made “modification kits” available at very attractive prices, to bring older models up to the current model status. Canard kits were sold to turn Pfledges into Ptravelers. Reduction drive kits turned Ptravelers into Ascenders. Fibreglass spring rods and new throttle quadrants turned Ascenders into Ascender IIs. Due to differences in design it was not possible to modify Ascender IIs into II+s or II+2s or Ptigers. As a result of the mod kits being available many earlier models were upgraded to later models. A large number of the Pfledges became Ascenders over time. Some Pfledge “purists” did keep their aircraft in original configuration and still fly them that way today, preferring the light weight, weight shift control and ease of set-up of the earlier designs. Even many of those surviving Pfledges were upgraded with some of the more desirable upgrades, such as nose wheel steering.

In 1984 a new group of partners offered to buy Pterodactyl Ltd from McCornack. Wanting to get back into research, design and development work, McCornack agreed to sell. The new company was set up in Rowlett, Texas under the name “Freedom Fliers” with Gary C. Vick as President. At the time of the production transfer Pterodactyl was producing five models – the Ascender II, Ascender II+, Ascender II+2, Ptiger and the Light Flyer. Freedom Fliers took the Light Flyer, Ascender II and Ptiger out of production and intended to concentrate on producing kits for the Ascender II+ and Ascender II+2 two seater models, along with their own Buckeye powered parachute line.

Freedom Fliers only produced a few machines before selling the company to a new concern, Penthusiants, under Todd Miller. Production was moved to Simi Valley, California where planes and parts were produced and sold. Miller owned the company for about a year before it was sold to yet another company. The new owners found it more profitable to build Buckeyes and sold off all remaining parts, tooling and blueprints in the late 1980's or early '90's. It is reported that another company, Coldfire Systems of California, produced a few custom order kits for a few people before they too disappeared

Times had changed and the whole aviation industry was going through a black period. The heady days of shipping hundreds of planes a year disappeared. There was a recession on and many companies stopped manufacturing – Cessna stopped all light plane production, as did Ultraflight, the Canadian manufacturer of the Lazair. Both of those companies cited liability insurance concerns in their shutdown of production. Many dozens of other ultralight manufacturers disappeared overnight. In an interview with Jack McCornack in 2001, he was of the opinion that the end was largely due to simple market saturation. After almost 6 years of frantic production almost everyone who wanted an ultralight had one. McCornack was never paid a cent for the company – the ensuing companies went out of business too quickly and disappeared. 1396 Pterodactyls had been produced.

 

By 1990 one of McCornack’s old dealers, Dave Froble, was getting short of spare parts. He was still flying three Pterodactyls – a Pfledge, an Ascender II and an Ascender II+2 two seater. Dave looked around for parts and came up empty – no one seemed to be supplying parts for the Pterodactyls. He tracked down and acquired Manta’s old stocks of parts and started collecting or making tubing, bolts and other parts. He created CAD-CAM drawings for all the parts for quality control. In 1991 he started DFE Ultralights with the aim of supplying parts to keep the remaining Pterodactyls flying.

By 1992 Froble had all the parts available and realized that he could ship complete kits if there was a demand. Froble was selling parts part-time while working as a software designer the full-time. Today he carries on Ascender development work when he has time to do so and is always working on improvements to the design.

At the present time DFE Ultralights has five different kits available. The DFE Ascender III-A is a weight-shift flying wing similar to the original Pfledge. The 2003 price for the Ascender III-A is $6800. The DFE Ascender III-B is the canard version, similar to the Ascender II and carries a 2003 price of $7900. The DFE Ascender III-C is a development of the heavy-duty Ascender II+ and sells for $8100. The Ascender III-C can also add the sidecar kit to become a two seater. The sidecar kit adds $534 to the price of the Ascender III-C, bringing it to $8634 with the 34 hp 430R engine. The DFE Ascender III-T hang glider tug is also available as a completely assembled aircraft.

All the DFE Ultralights Ascender III designs incorporate many evolutionary improvements, like steerable nose gear, lateral and longitudinal winglet braces and Mylar covering on the canard. The standard engine for most of the designs is still the Cuyuna (now produced by 2 Stroke International) 430R. The two-seat version of the III-C and also the single seat III-T Tug have the Rotax 503 DCDI dual carburetor-equipped 50 hp powerplant as the recommended engine, giving both models excellent take-off and climb performance. The basic cost of the two seater Ascender III-C with the Rotax 503 DCDI engine, in 2001, was about $10,500.

When inflation is accounted for, the present-day prices of DFE Ascenders are actually about 20% lower than the price of a comparable Pterodactyl Ascender in 1981-83! They are truly a bargain in today’s aviation marketplace.

DFE Ultralights continues to produce these five kit planes and parts for all the Pterodactyl models. For more information on the current production models of the Ascender III or parts to keep an older Pterodactyl flying, contact Dave Froble.


DFE Ultralights Handy DAC Evolution Chart

By Dave Froble

This is a quick reference chart to help you determine which model Pterodactyl you have.

Pterodactyl Model

Wing Spar Size

Canard

Engine

Propeller

Other Features

Pfledge OR (Oshkosh Replica)

All 1 1/2" dia except rear inner section 1 5/8” diameter

No

Sachs SA-340 direct drive

36 x 16

 

Pfledge 430D

All 1 1/2” dia except rear inner section 1 5/8” diameter

No

Cuyuna 430D direct drive

36 x 16

 

NFL (Not foot launchable)

All 1 1/2” dia except rear inner section 1 5/8” diameter

No

Cuyuna 430D direct drive

36 x 16

Rear mounted elevator

Ptraveler

All 1 1/2” dia except rear inner section 1 5/8” diameter

Yes

Cuyuna 430D direct drive

36 x 16

 

Ascender

All 1 1/2” dia except rear inner section 1 5/8” diameter

Yes

Cuyuna 430 R w/ 2:1 belt reduction

54 x 27

 

Ascender II

All 1 1/2” dia except rear inner section 1 5/8” diameter

Yes

Cuyuna 430 R w/ 2:1 belt reduction

54 x 27

Fiberglass spring rod main gear; side mount throttle; muffler

Ascender II+

All 1 3/4” diameter

Yes

Cuyuna 430 R w/ 2:1 belt reduction

54 x 27

20 1/2” wide hang cage; 1 1/8” dia main and rear struts

Ascender II+2

All 1 3/4” diameter

Yes

Cuyuna 430 R w/ 2:1 belt reduction

54 x 27

20 1/2” wide hang cage; 1 1/8” dia main and rear struts; w/ side car

Ptiger

Yes

Wing span under 30’

Cuyuna 430 R w/ 2:1 belt reduction

54 x 27

Fiberglass fuselage