Aircraft

Business jets are typically flown by commercial pilots, although there is a new generation of small jets arriving soon for private pilots. Work in the theory of auctions contributed to Vickrey's 1996 Bank of Sweden Prize. Piston-powered propeller aircraft (single-engine or twin-engine) are especially common for both private and commercial general aviation, but even private pilots occasionally own and operate helicopters like the Bell JetRanger or turboprops like the Beechcraft King Air. These two auctions are also theoretically equivalent, but in practice Dutch auctions will produce less revenue than sealed first-price auctions (one of the important results of Experimental economics). Commercial general aviation pilots use aircraft for a wide range of tasks, such as flight training, pipeline surveying, passenger and freight transport, policing, crop dusting, and medical transport (medevac). This behavior is known as bid shading. Usually these private pilots own their own aircraft and take out loans from banks or specialized lenders to purchase them. Bidders in the traditional Dutch auction and sealed first-price auction will tend to underbid what they believe the item is truly worth in hopes of getting the item for less, or in order to avoid the winner's curse.

Private pilots use aircraft primarily for personal travel, business travel, or recreation. This system creates a tension between the desire to hold back on bidding since later items will almost certainly be cheaper, and the chance that by losing the first round of bidding all possibility of purchasing will be lost. Within general aviation, the major distinction is between private flights (where the pilot is not paid for time or expenses) and commercial flights (where the pilot is paid by a customer or employer). Items the winning bidder opts not to purchase are auctioned again. The vast majority of flights flown around the world each day belong to the general aviation category, ranging from recreational balloon flying to civilian flight training to business trips to firefighting to medevac flights to cargo transportation on freight aircraft. Once each item has been priced, the winning bidder is entitled to buy the remaining goods at the same price. Civil aviation includes both scheduled airline flights and general aviation, a catch-all covering other kinds of private and commercial use. It is also possible to auction each identical item individually.

By the time of the Vietnam War, helicopters had come into widespread military use, especially for transporting and supporting ground troops. In a Vickrey auction, the pricing rule is more complicated, but preserves the property that bidders will bid their true valuation. Tankers were developed after World War II to refuel other aircraft in mid-air, thus increasing their operational range. Bidders will not typically bid their true value in a uniform-price auction with multiple units. In order to prevent the enemy from bombing, fighter aircraft were developed to intercept and shoot down enemy aircraft. In a uniform-price auction, all of the winning bidders pay the price submitted by the highest non-winning bidder. During World War I many types of aircraft were adapted for attacking the ground or enemy vehicles/ships/guns/aircraft, and the first aircraft designed as bombers were born. If more than one identical item is sold, there are two possible generalizations of the second-price auction.

Combat aircraft themselves, though used a handful of times for reconnaissance and surveillance during the Italo-Turkish War, did not come into widespread use until the Balkan War when first air-dropped bomb was invented and widely used by Bulgarian air force against Turkey. A more detailed differentiation would be between:. In the past, gliders and balloons have also been used as military aircraft; for example, balloons were used for observation during the American Civil War and World War I, and cargo gliders were used during World War II to land intruding German troops in many European countries in the 1940/42 period, while Allied troops used them in Europe after D-Day . In terms of auctioneers and auction items, we can differentiate three types of auctions:. Even the little fabric-covered two-seater Piper J3 Cub had a military version, the L-4 liaison, observation and trainer aircraft. . military and the Dakota in Britain and the Commonwealth. Civil War, Colonels of the armies were called upon to auction off the spoils of war.

Many civil aircraft have been produced in separate models for military use, such as the civil Douglas DC-3 airliner, which became the military C-47/C-53/R4D transport in the U.S. In the U.S., auctioneers who have completed Auctioneer School commonly use the title Colonel and are given this honorary title because in the U.S. Combat aircraft like fighters or bombers represent only a minority of the category. Some jurisdictions require auctioneers to be licensed and bonded. The major distinction in aircraft usage is between military aviation, which includes all uses of aircraft for military purposes (such as combat, patrolling, search and rescue, reconnaissance, transport, and training), and civil aviation, which includes all uses of aircraft for non-military purposes. Auctioneers are usually trained in the legal and practical aspects of conducting auctions. They are restricted to rather specialised niches, such as spaceflight, where no oxygen is available for combustion (rockets carry their own oxygen). Auction catalogs are frequently printed and distributed before auctions of rare and/or collectible items; these catalogs may be very elaborate works, with considerable details about the items being auctioned.

Rocket aircraft have occasionally been experimented with. Internet auctions have become very popular; the world's largest auction site is eBay. In addition to turbine engines like the turboprop and turbojet, other types of high-altitude, high-performance engines have included the ramjet and the pulse jet. The world's three largest auction houses are Christie's, Sotheby's and Bonhams. Helicopters also typically use turbine engines. Examples of this type of auction include:. Pressurised aircraft, however, are more likely to use the turbine engine, since it is naturally efficient at higher altitudes and can operate above 40,000 ft. Although less publicly visible, the most economically important auctions are the commodities auctions in which the bidders are businesses even up to corporation level.

During the forties and especially following the 1973 energy crisis, development work was done on propellers with swept tips or even scimitar-shaped blades for use in high-speed commercial and military transports. Auctions are publicly seen in several contexts:. Piston engines normally become less efficient above 7,000-8,000 ft (2100-2400 m) above sea level because there is less oxygen available for combustion; to solve that problem, some piston engines have mechanically powered compressors (blowers) or turbine-powered turbochargers or turbonormalizers that compress the air before feeding it into the engine; these piston engines can often operate efficiently at 20,000 ft (6100 m) above sea level or higher, altitudes that require the use of supplemental oxygen or cabin pressurisation. In the context of auctions, a bid is an offered price. Piston engines typically operate using avgas or regular gasoline, though some new ones are being designed to operate on diesel or jet fuel. In some cases, there is a minimum or reserve price; if the bidding does not reach the minimum, there is no sale (but the person who puts the item up for auction still owes a fee to the auctioneer). Water cooled V engines, as used in automobiles, were common in high speed aircraft, until they were replaced by jet and turbine power. In economic theory an auction is a method for determining the value of a commodity that has an undetermined or variable price.

(See also: Aircraft engine.) The piston engine is still used in the majority of aircraft produced, since it is efficient at the lower altitudes used by small aircraft, but the radial engine (with the cylinders arranged in a circle around the crankshaft) has largely given way to the horizontally-opposed engine (with the cylinders lined up on two sides of the crankshaft). An auction is the process of buying and selling things by offering them up for bid, taking bids, and then selling the item to the highest bidder. Until World War II, the internal combustion piston engine was virtually the only type of propulsion used for powered aircraft. This complexity is overcome by feeding the bids into an optimization algorithm (such as a linear programming problem). Airships combine a balloon's buoyancy with some kind of propulsion, usually propeller driven. Sorting out which buyers win which bundles (and sometimes the amount they must pay for them) is usually computationally complex. For gliders, takeoff takes place from a high location, or the aircraft is pulled into the air by a ground-based winch or vehicle, or towed aloft by a powered "tug" aircraft. They may also offer to purchase one bundle of goods or another, but not both.

Balloons drift with the wind, though normally the pilot can control the altitude either by heating the air or by releasing ballast, giving some directional control (since the wind direction changes with altitude). Such combinatorial bids may offer to pay a certain amount if all units of a buyer-specified bundle are awarded, but nothing otherwise. Some types of aircraft, such as the balloon or glider, do not have any propulsion. This dilemma can be overcome by selling all goods simultaneously and allowing buyers to submit bids on combinations of goods. These designs may have potential but are not yet practical. If forced to purchase each component of a bundle in a separate auction, the bidder faces a dilemma: bidding enough to win the components of the bundle that are sold first may result in a financial loss if he fails to win the components that are sold later, but failing to purchase the components that are sold first ensures that he will not win the bundle. And finally the flapping-wing ornithopter is a category of its own. For instance, if bicycle wheels and bicycle frames are sold separately in an auction, a bidder may value a bundle consisting of a single wheel or a single frame at $0, but may value the bundle of two wheels and one frame at $200.

It is (2005) in development in the United Kingdom. Combinatorial Auction: In some cases, a buyer's value for the goods that are up for auction is a complex interaction of the type and number of goods he receives (known as a "bundle"). This uses a fixed wing with a forced airflow produced by cylindrical fans mounted above. If no bidder chooses to utilize the buy-out option, the auction ends with the highest bidder winning the auction. A recent innovation is a completely new class of aircraft, the fan wing. The bidder can choose to bid or use the buy-out option. A further category might encompass the wing-in-ground-effect types, for example the Russian ekranoplan also nicknamed the "Caspian Sea Monster" and hovercraft; most of the latter employing a skirt and achieving limited ground or water clearance to reduce friction and achieve speeds above those achieved by boats of similar weight. The buy-out price is set by the seller.

Some craft have reaction-powered rotors with gas jets at the tips but most have one or more lift rotors powered from engine-driven shafts. Buy-out auction: This auction has a predetermined buy-out price in which the bidder can end the auction by accepting the buy-out price. The best-known examples are the helicopter, the autogyro and the tiltrotor aircraft (such as the V-22 Osprey). This a popular online type of auction. Here, the lift is provided by rotating aerofoils or rotors. If the top five bids are 10, 10, 9, 8, 8 then 9 would be the winner being the highest unique bid. A second category of aerodynamically lifted aircraft are the rotary-wing aircraft. For instance an auction is given a maximum bid of 10.

So far the only significant practical application of the lifting body is in the Space Shuttle, but many aircraft generate lift from nothing other than wings alone. The highest, or lowest, unique bid wins. The lifting body configuration is where the body itself produce lift. Unique bid auction: In this type of auction users post blind bids and are given a range of prices they can place a bid in, often a capped limit. A variable geometry ('swing-wing') has also been employed in a few examples of combat aircraft (the F-111, Panavia Tornado, F-14 Tomcat and B-1 Lancer, among others). This type of auction is being replaced by electronic trading platforms. the B-2 Spirit). Transactions may take place simultaneously at different places in the trading pit or ring.

Other possibilities include the delta-wing, where lift and horizontal control surfaces are often combined, and the flying wing, where there is no separate vertical control surface (e.g. Open outcry auction: This type of auction is used in stock exchanges and commodity exchanges, where trading occurs on a trading floor and traders may enter verbal bids and offers simultaneously. This is principally an improvement in structures and not aerodynamics. The seller may review the bids and close with a price of their choosing at any time—the successful bidders that pay this price are those whose bid meets or exceeds it, and these are the only bidders who receive a copy of the item. Subsequently most aircraft are monoplanes. Digital art auction: In this indefinitely long auction, designed for unreleased works that are trivially reproducible at zero cost (recordings, software, drug formulae), bidders openly submit their maximum bids (which may be adjusted or withdrawn at any time). The number of lift surfaces varied in the pre-1950 period, as biplanes (two wings) and triplanes (three wings) were numerous in the early days of aviation. At the end of the auction, the lowest bid wins.

Canards are becoming more common as supersonic aerodynamics grows more mature and because the forward surface contributes lift during straight-and-level flight. The buyer puts out an RFQ for a given commodity and providers offer progressively lower prices in hopes of getting the business. The other configuration is the canard where small horizontal control surfaces are placed forward of the wings, near the nose of the aircraft. Procurement auction: This kind of auction reverses the roles of seller and buyer. In a "conventional" configuration, the lift surfaces are placed in front of a control surface or tailplane. The highest bidder pays the price they submitted. Much aerodynamic work was done with kites until test aircraft, wind tunnels and now computer modelling programs became available. They may or may not know how many other people are bidding or what their bids are.

Kites depend upon the tension between the cord which anchors it to the ground and the force of the wind currents. Participants submit bids normally on paper, near the item. The forerunner of these type of aircraft is the kite. Silent auction: This is a sealed variant often used in charity events, but involving the simultaneous sale of multiple items. Among aerodynamically lifted aircraft, most fall in the category of fixed-wing aircraft, where horizontal airfoils produce lift, by profiting from airflow patterns determined by Bernoulli's equation and, to some extent, the Coanda effect. Implemented as such, this is known as a Japanese Auction. With engine lift, the aircraft defeats gravity by use of vertical Examples of engine lift aircraft are rockets, and VTOL aircraft such as the Hawker-Siddeley Harrier. When all but one bidder drops out, the good is allocated to the remaining bidder at the price at which the second-to-last bidder dropped out.

In the case of aerodynamic lift, the aircraft is kept in the air by wings or rotors (see aerodynamics). True strategic equivalence requires a modified model of the English ascending auction in which the price rises continuously with bidders choosing when to drop out. In heavier-than-air aircraft, there are two ways to produce lift: aerodynamic lift and engine lift. In theory, this is mathematically equivalent to the English auction, because in both the first-place bidder receives the item at a price equal to the second-place bidder's willingness to pay, plus the bid increment. Several accidents, such as the Hindenburg fire at Lakehurst, NJ, in 1937 led to the demise of large rigid airships. Sealed second-price auction, also known as a Vickrey auction: This is identical to the sealed first-price auction, except the winning bidder pays the second highest bid rather than their own. The most successful type of rigid airship was the Zeppelin. The highest bidder pays the price they submitted.

Examples of lighter-than-air aircraft include non-steerable balloons, such as hot air balloons and gas balloons, and steerable airships (sometimes called dirigible balloons) such as blimps (that have non-rigid construction) and rigid airships that have an internal frame. In this type of auction all bidders simultaneously submit bids so that no bidder knows the bid of any other participant. A first division by design among aircraft is between lighter-than-air, aerostat, and heavier-than-air aircraft, aerodyne. Sealed first-price auction: Also known as Sealed High-Bid Auction or First-Price Sealed-Bid Auction (FPSB). Below, we describe classifications by design, propulsion and usage. Economists call the latter auction a multi-unit English ascending auction. There are several ways to classify aircraft. "Dutch auction" is also sometimes used to describe online auctions where several identical goods are sold simultaneously to an equal number of high bidders.

Aircraft fall into two broad categories:. The Dutch auction is named for its best known example, the Dutch tulip auctions; in the Netherlands this type of auction is actually known as a "Chinese auction". . This type of auction is convenient when it is important to auction goods quickly, since a sale never requires more than one bid. An aircraft is any machine capable of atmospheric flight. That participant pays the last announced price. The distinction between a balloon and an airship is that an airship has some means of controlling both its forward motion and steering itself, while balloons are carried along with the wind. Dutch auction: In the traditional Dutch auction the auctioneer begins with a high asking price which is lowered until some participant is willing to accept the auctioneer's price, or a predetermined minimum price is reached.

In particular, these aircraft use a relatively low density gas such as helium, hydrogen or heated air, to displace the air around the craft. The seller may set a 'reserve' price and if the auctioneer fails to raise a bid higher than this reserve the sale may not go ahead. Aerostats use buoyancy to float in the air in much the same manner as ships float on the water. The auction ends when no participant is willing to bid further, or when a pre-determined "buy-out" price is reached, at which point the highest bidder pays the price. Lighter than air aerostats: hot air balloons and airships. Participants bid openly against one another, with each bid being higher than the previous bid. Mainly used internationally. English auction: This is what most people think of as an auction.

STOL stands for Short Take Off and Landing. dealer auction - for collectibles. The abbreviation VTOL is applied to aircraft other than helicopters that can take off or land vertically. sale auction - for art and one-of-a-kind items. Helicopters and autogyros use a spinning rotor (a rotary wing) to provide lift; helicopters also use the rotor to provide thrust. The participants include a number of core professional buyers, who monitor each other to ensure that no one is 'cheating' on the community. For a glider to maintain its forward speed it must descend in relation to the air (but not necessarily in relation to the ground). exchange auction - also known as commodity auctions or exchange-commodity auctions, are the most closed to the new participants.

Exceptions are gliders which have no engines and gain their thrust, initially, from winches or tugs and then from gravity and thermal currents. In most cases, investors can also place so called non-competitive bids which indicates an interest to purchase the debt instrument at the resulting price, whatever it may be. The movement of air over the airfoil produces lift that causes the aircraft to fly. The auction is usually sealed and the uniform price paid by the investors is typically the best non-winning bid. Fixed-wing aircraft generally use an internal-combustion engine in the form of a piston engine (with a propeller) or a turbine engine (jet or turboprop), to provide thrust that moves the craft forward through the air. debt auctions, in which governments sell debt instruments, such as bonds, to investors. Heavier than air aerodynes, including autogyros, helicopters and variants, and conventional fixed-wing aircraft: aeroplanes in Commonwealth English (excluding Canada), airplanes in North American English. environmental auctions, in which companies bid for licenses to avoid being required to decrease their environmental impact.

electricity auctions, in which large-scale generators and consumers of electricity bid on generating contracts. timber auctions, in which companies purchase licenses to log on government land. spectrum auctions, in which companies purchase licenses to use portions of the electromagnetic spectrum for communications (for cell phone networks, for example). sales of businesses.

in legal contexts where forced auctions occur, as when one's farm or house is sold at auction on the courthouse steps. in thoroughbred horseracing, where yearling horses are commonly auctioned off; and. in commodities auctions, like the fish wholesale auctions. for the sale of second-hand goods of all kinds, particularly house clearances and online auctions.

in the sale of collectibles such as stamps, coins, classic cars, luxury real estate, and fine art. in the antique business, where besides being an opportunity for trade they also serve as social occasions and entertainment.