Pterodactyl ultralight aircraft, Pterodactyl experimental aircraft, Pterodactyl experimental light sport aircraft (ELSA), Lightsport Aircraft Pilot News newsmagazine.

The PTERODACTYL FLEDGLING is an ultralight motor glider based on the Manta Fledge II B hang glider. It is fully collapsible for transport or storage. At this time no license or registration is required, but it is possible that a student pilot's license will be required sometime in the future. Registration may also be required. This kit has been designed to comply with the FAA's "51% amateur built" requirement for experimental aircraft registration.

The steps involved in constructing your PTERODACTYL FLEDGLING are airframe assembly, rigging, landing gear assembly, power unit assembly, and wing cover installation. It is recommended that you give yourself a full day for the rigging, but each of the other steps can be done in an evening or two.

We can't tell you how long it will take you to build yours. At Manta, a dedicated crew of two builds three Fledgling hang gliders a day. On the other hand, if you only work on it after work and before dinner, figure a month. No gluing, doping or painting is required, as the wing covering and rudders are pre-built and all tubing is anodized.

The airframe kit is ready to ship two weeks after we receive your order. The power plant and landing gear kit go out in three weeks. The custom sail requires five weeks, between Pterodactyl and Manta we've got the sailmaker pretty busy. When you design the colors of your wing covering, use blue and green sparingly if at all. Yellow and orange are the easiest colors to see.

The price and specifications shown ore for the PTERODACTYL FLEDGLING with landing gear and PTERODACTYL 'X' power plant. The landing gear uses shock-cord suspension and 16" bicycle wheel mains to allow takeoffs and landings at unimproved fields. The power plant uses a 242cc snowmobile engine with a direct driven 36" prop. It's a lot quieter and more fuel efficient than last year's system, which used a reduction drive 136cc Chrysler. The price includes seat, sail bag, rib bag, and a shipping and storage tube. If you're comparing costs with other aircraft, remember the portability of the PTERODACTYL FLEDGLING means no trailer or hanger is needed.

To expedite your order, include a cashier's check or money order for the full amount. We will ship your airframe kit in two weeks, followed by the power kit and the wing cover. This way you'll be flying roughly six weeks after you place your order. If you prefer, you can send 50% down with your order, the balance due when your complete PTERODACTYL FLEDGLING kit is ready to ship.

Landing approach on a minimal airstrip. The pilot shown is quite experienced. The runway isn't much wider than the landing gear.

LANDING TECHNIQUE

On final approach, maintain 25 MPH airspeed or more. Flying too slow puts the aircraft close to stall and reduces the effectiveness of the rudders for glideslope control. On final, both rudders should be out slightly. Glide can then be extended or shortened by reducing or increasing the amount of rudder deployment. For glare, fully deploy both rudders. The increased drag above the center of gravity will lift the nose and increase angle of attack. Touch down on the main wheels first. After landing, use the rudders to control direction during rollout.

TAKEOFF TECHNIQUE

The landing gear holds the aircraft at a positive angle of attack, so all the pilot has to do to take off is accelerate to flying speed and keep aimed down the runway. Low speed steering is done by turning the nose wheel, but from 10 MPH on up, rudders must be used. At approximately 20 MPH, the PFLEDGE leaves the ground. In no wind, this takes roughly 250 feet. The pilot moves forward slightly, to trim at an airspeed of 30 MPH, which gives best rate of climb and is well above stall speed.

Final flare. Note the fully deployed rudders. The runway is as wide as the wingspan and suitable for training.

PTERODACTYL 'X'

The PTERODACTYL 'X' is a drive unit using a Xenoah 242cc engine. The system weighs about ten pounds more than the 136cc Chrysler used in our earlier power unit. We de-tune the engine with a restrictive (and quiet) muffler and high pitch prop, which drops its max horsepower from 22 at 7000 RPM to 16 at 5800 RPM. The Chrysler is rated at 8HP, we were bumping it up to about 10. As well as being more powerful, our 'X' package is a lot more reliable. The other engine didn't last real long at 125% of rated power, the 'X' is only running 75%,

The biggest performance increase has been in cruise. We travel cross country a lot now days, usually at 45 MPH indicated. It'll maintain altitude at 50 with me in it (I weigh 187 in my stocking feet) but at that speed fuel consumption is roughly 1? gallons per hour. Throttled back to 40 MPH consumption is less than 1 GPH, by putting around at 30-35 and looking for lift it can get down to ? GPH.

Climb rate isn't much greater than before (about 300 FPM) but it's now capable of climbing over a very broad speed range. The 'X' power plant will climb about 100 FPM at 45, with the Chrysler reduction system 45 was top speed and the plane was losing altitude fast.

There are microlight aircraft advertised at twice the climb rate of the PFLEDGE that can't climb with us in actual practice. 300 FPM is not the highest number we've read on a vario, it's not a calculation based on static thrust, it's not based on the aircraft's potential without a pilot, it's a plain old stopwatch-and-altimeter measurement with a stock motor and a tank full of regular. If you have a special application that requires a greater climb rate (such as crop dusting) we can install a reduction drive on the Xenoah as easy as the Chrysler, and we can bump up the horsepower to 25 or so. But don't expect it to be as good as a cross country machine, it won't be as reliable as our present unit and it'll be a gas hog.

This new drive unit is the main reason the '79 PFLEDGE costs 10% more than the '78. Even in lots of a hundred, the Xenoah costs more than twice the price of the Chrylser. We feel it's well worth it.

There's one aspect of performance where the Chrysler system was superior to the 'X'. It still takes off in 250 feet, but it takes three seconds longer to get there. That's because static thrust is 20 pounds lower with our new system (65 instead of 85), and this reduces the acceleration from 0 to 10 MPH. In order to take advantage of the power availble from the 'X' at high speed and to give a low RPM cruise, propeller pitch is too high for optimum static thrust. As well as efficiency losses caused by the prop's excessive angle of attack, it loads the engine so much it'll only turn 4000 RPM on the ground so the engine's only putting out 8 to 10 horsepower. At 50 MPH we get 5800 RPM and 16 horsepower, and 80 pounds of thrust. It's like having a car with only one gear. If it's third, it'll be a dog away from the stop lights.

There are drive units on the market which have been optimised for static thrust. Static demonstrations have proven to be an effective selling tool. To achieve maximum static thrust, the engine must run at peak horsepower at zero airspeed. As airspeed increases and RPM goes up past peak horsepower and into a range where the engine becomes rather short fused. It's like having a car stuck in first, you can't expect it to hang together very long on the freeway.

Well, aircraft design is filled with compromises. We chose to give away some performance on the ground in exchange for increase flight performance. So if you want to take off at dawn, you're going to have to set your alarm three seconds earlier than you did flying last year's model.

Finally we've got something where we can take off Saturday morning with a sleeping bag and gas money, log a couple hundred miles, and come back Sunday evening. The landing gear is capable of handling fields I'd rather not even walk in, so we're not stuck in the airport-to-airport rut. For real soft stuff (like loose sand) you can put one of the 16" wheels on the nose and mount 20" mains, as shown on the first couple of pages. I don't have them on mine because of the extra weight and parasitic drag, but then again it took me 800 feet to get off a beach once.

Please write us with questions and suggestions so we can have a question and suggestion column in Vol.1, #2 of THE PTIMES.

Jack McCornack Editor

Toni James Publisher