“Powered parachute”的意思、由来-开放百科全书

A powered parachute, often abbreviated PPC, and also called a motorised parachute or paraplane, is a type of aircraft that consists of a parachute with a motor and wheels. The aircraft's airspeed is typically about 25–35 mph (40–60 km/h). PPCs operate safely at heights ranging from a few feet off the ground (while ground skimming, a popular use of the aircraft) to altitudes as high as 10,000+ ft (5.5 km), but typical operating heights are between 500 and 1500 feet (150–500 meters) above ground level (AGL). Equipped with a standard 5 or 10 gallon fuel tank, PPCs can typically be flown for about three hours before requiring refueling. They have very short take-off and landing rolls, sometimes less than 100 ft (30 m). PPCs are among the least expensive aerial vehicles. A new one-person powered parachute may cost as little as $10,000, though double-seaters more typically cost about $20,000. Top end two-seater PPCs usually cost $25,000–$35,000. Empty weight is typically around 200–300 lb (90–135 kg) and payload can be upwards of 500 lb (225 kg). In the United States, many of the smallest single-seat PPCs are flown under 14 C.F.R. § 103 of the Federal Aviation Regulations,^[1] which allows them to be flown without a license or flight instruction. Flight instruction is, however, highly recommended, and an average student can learn to fly a PPC safely with 5 to 10 hours of flight instruction. Two-seat PPCs are light sport aircraft in the United States. The pilot must have at least a sport pilot certificate issued by the FAA to fly them. A minimum of 12 hours of flight instruction, including 2 hours of solo as a student pilot, is required to obtain this certificate.^[2] Powered parachuting is not to be confused with powered paragliding.

Safety

PPCs are often considered to be safer than normal fixed-wing aircraft because of their inherent stability, limited response to control inputs, and stall resistance. There are two primary means to control a PPC: increasing or decreasing engine power (which controls vertical rate of climb) and deflecting the right or left trailing edge of the parachute—typically by moving the steering bars with the feet—which turns the aircraft right or left. If the trailing edge of the wing is pulled in on both sides at the same time, the aircraft "flares", i.e., slows and temporarily gains additional lift. The flare is generally used to make fine adjustments in altitude when flying close to the ground and, in particular, when landing.^[3]

The power-off glide ratio of a powered parachute ranges from 3:1 to 6:1. Glide ratio varies depending on the chute size and shape, and the weight that the chute is carrying. Engine-off landings are generally safe, provided that the aircraft is within glide range of a suitable landing zone and the pilot is properly trained in the use of proper "flaring" technique. "Flaring", in terms of powered parachuting, refers to the usage of the steering bars pushed out simultaneously, causing the aircraft to rock forward. This is caused by the reshaping of the rear of the wing or parachute, which is pulled downwards. This results in the entire aircraft rocking on the transverse axis, thus slowing the aircraft momentarily, allowing an engine-out landing to become less brutal within the last few feet off the ground. Done properly, flaring will allow an engine-out landing to be much smoother than simply relying on the lift of the ram-air canopy to cushion the landing.^[3]

Although possible, it is difficult to cause the aircraft to get into a dangerous attitude, stall, or chute collapse by means of pilot control inputs. Chute collapse is considered by many pilots to be virtually impossible with square wings. The wing is more likely to collapse with the more maneuverable, but inherently less stable, elliptical wing, but such collapses are normally followed by an immediate reflation and often go unnoticed by the pilot. In the rare circumstances where an elliptical wing collapses, the collapse is caused either by some extreme adverse meteorological condition or by pilot error. The Federal Aviation Administration reports that over 80 percent of all aviation accidents are due to pilot error. Inflatable ram-air elliptical wings can have upward of 30 individual cells whereas square wings typically have fewer than 13 cells.^[3]

The main hazards one faces while flying a powered parachute are associated with wind and obstacles. Flight should not be attempted in winds exceeding 10–15 mph or in gusty conditions. Wind hazards include terrain-induced air disturbances called rotors (it is advisable to stay upwind of trees, mountains, and other obstacles that disturb the flow of the wind). Wake turbulence created by the passage of other aircraft (referred to as "wingtip vortices"), especially aircraft that are heavy, aerodynamically "dirty", and slow, pose another significant hazard. Also, since the slow-moving powered parachutes, like helicopters, are particularly well equipped to fly safely near the ground, special care must be taken to avoid power lines, trees, and other low-level terrain obstacles.^[3]

Operations

PPC pilots typically enjoy flying low and slow, and the PPC is an excellent platform for sightseeing and photography. PPCs are also used in agriculture, and occasionally by law enforcement agencies and flight search organizations.

PPCs do not need an airport to take off and land. Many pilots choose and prefer to fly from back yard strips, small airports, and mowed hay fields.

In the United States, Part 103 ultralight PPCs (like other classes of ultralight aircraft) are not allowed to fly at night, and not over densely populated areas.^[1] However, the FAA implemented the sport pilot rule in 2004, which expanded the areas over and airspace in which light sport aircraft (LSA) PPCs can legally fly. In fact, a properly equipped PPC may even be flown at night or over metropolitan areas by a private pilot with a PPC rating.

Uses

Law enforcement

A powered parachute as operated in the observation platform role by the Ripon Police Department and other police departments has assisted with suspect captures, river rescues, critical infrastructure over-flights, crime scene photos, narcotics enforcement and crime suppression at a small fraction of the cost of a police helicopter. This low-cost aviation asset was procured from the US Department of Justice, Aviation Technology Program.^[4]^[5]^[6]

Emergency medical services

The I-Fly Maverick is a street-legal experimental certified aircraft designed to provide emergency medical services to the Huaorani indigenous people in the Amazon rainforest in Ecuador.

Hunting and scouting

It is generally illegal in the U.S. to actually hunt/shoot from any aircraft, except in very limited certain circumstances.^[7] However, a powered parachute is considered an ideal aircraft for initially scouting animal and herd locations in the days or weeks prior to a hunting season, due to its naturally slower flight characteristics. During hunting season, most U.S. states have additional rules about mandatory waiting periods between the time a hunter uses an aircraft and can actually hunt,^[8] and virtually all have restrictions and serious penalties for the use of any aircraft to hunt in real-time (e.g., air-to-ground collaboration/communications). With outright bans by many states disallowing UAV use in any situation related to hunting and wildlife harassment, powered parachutes are considered by some to be a more animal-friendly and cost-effective alternative.

History

In 1930, a cover article in Modern Mechanix, October issue, described the project of Buddy Bushmeyer for a powered parachute.

After World War II, sport jumping became a recreational activity. The sport started with round parachutes, ranging in size from 20 to 30 feet in diameter.^[3]

On October 1, 1964, Domina Jalbert applied for patent for his new "Multi-Cell Wing" named "parafoil" (also known as a "ram-air" wing), which was a new parachute design. His ideas were registered as U.S. patent 3,285,546 on November 15, 1966.^[3]

The possibilities of the design quickly became apparent: increased glide ratios were possible and the distance traveled could likely be extended, assuming the person or payload suspended under the chute had some thrust added. With even more power, the angle of attack could be shifted, and the wing could fly level or even climb.

In 1968, Lowell Farrand flew a motorized version called the “Irish Flyer I”, developed by Dr. John Nicolaides at Notre Dame University. It was a modified standard Benson gyrocopter, with the rotor removed and replaced by a 6-foot cross-member to which the parafoil was attached. The propeller was shrouded in order to avoid entanglement with the parafoil lines. Irish Flyer I was tested in the summer of 1968 by towing it aloft and releasing it for extended powered glides. Over the proceeding years, additional tow-based prototypes were developed and flown.^[9]

The later development of the first mass-produced powered parachute took approximately two and one-half years.

Aeronautical engineer Steve Snyder was implementing and perfecting the use of the square ram-air parachutes, and decided to pursue the idea and objective of creating a safe and simple aircraft that even amateurs could launch and fly easily.

The first powered parachute that could take off under its own power flew in 1981 when Steve Snyder, Dan Thompson, and Adrian Vandenburg combined their talents and inspiration. It was Snyder's idea to take skydiving's newest parafoil designs and add newer (and lighter) engines, while Vandenburg's skills as a machinist were critical to building the cockpit frame that was completed in March 1981. Daniel Thompson, an ultralight-aircraft designer and small-engine mechanic, was brought onto the project three months later to identify a power plant for the aircraft. He fitted the aircraft with two small Chrysler engines, resulting in the first prototype P-1 aircraft.^[10]

On the first day of test flight, attempts were made to simply get the powered parachute aircraft off the ground. Snyder, at 150 lbs., finally tried easing the power away from full throttle at take-off, and managed to fly the craft to a height of 40 to 50 feet. Snyder had a difficult time with control of the craft because of the torque produced by both engines' propellers spinning in the same direction. The total flight time was 30–35 seconds at a speed of 20 to 25 mph. The P-1 flew more than 10 times, once by a woman weighing 110 lbs., which allowed for better performance of the test flights. Many revisions were made during those test flights, including the addition of a vertical stabilizer, flaps, ailerons, and optimization of the parachute trim.

Ram air parachutes of the day had a flat profile and offered limited control. As a result, a more anhedral (downward curve) design was applied and ribs were added to the parachute, ultimately giving the aircraft more stability and pressurization and solving the control issue.

While the parachute control solutions were being worked out, Thompson developed an improved airframe design, including Snyder's idea of folding landing gear for portability. The problem of torque was resolved by having the propellers counter-rotating, thus canceling out each other's torque effect. The P-2 aircraft was completed in January 1983.

Design and construction of the P-3 started on February 26, 1983. Three months later the prototype made its debut at the Sun & Fun Airshow in Florida. Response was overwhelming, and the ParaPlane Corporation was formed to produce the P-3 powered parachute. Since that time, many innovations and improvements have developed.^[11]

Comparisons with Powered Paragliding

There is often confusion about the differences between powered parachutes (PPC) and powered paragliding (PPG). In simple terms, paragliding can be most easily recognized and differentiated by flight systems that use the hands to operate the steering controls, while powered parachuting steering controls use steering bars pushed on by the foot. PPCs will always use a rolling airframe (also called a cart, trike, or quad, depending on the configuration), while a rolling airframe is usually considered a higher end option in paragliding.

Any other distinctions are less clear. All paragliding equipment must fall within 14 C.F.R. § 103, and pilot licensing (in the strict legal sense) is not applicable. Other lines are blurred further. For example, some people previously argued that only 2-person flight is allowed using a PPC, but 2-person ("tandem") paragliding is readily doable in many countries throughout the world, and limited types of tandem paragliding are legally authorized in the U.S. through 2020 as a result of an FAA exemption.^[12]

With advances in technology, perhaps the biggest reason for confusion nowadays comes from the fact that the 'high end' of paragliding - which involves using a motor permanently connected to a lightweight wheeled airframe with a seat - looks nearly identical to PPC airframes designed under FAA 14 C.F.R. § 103 rules. In fact, some manufacturers have even produced lightweight rolling airframes that are completely identical, save for the addition of wider canopy attachment points and foot steering bars on the PPC versions.

Model Engineering