Alternating current is an electric current which periodically reverses direction, in contrast to direct current which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, it is the form of electrical energy that consumers use when they plug kitchen appliances, televisions and electric lamps into a wall socket. A common source of DC power is a battery cell in a flashlight; the abbreviations AC and DC are used to mean alternating and direct, as when they modify current or voltage. The usual waveform of alternating current in most electric power circuits is a sine wave, whose positive half-period corresponds with positive direction of the current and vice versa. In certain applications, different waveforms are used, such as square waves. Audio and radio signals carried on electrical wires are examples of alternating current; these types of alternating current carry information such as sound or images sometimes carried by modulation of an AC carrier signal.
These currents alternate at higher frequencies than those used in power transmission. Electrical energy is distributed as alternating current because AC voltage may be increased or decreased with a transformer; this allows the power to be transmitted through power lines efficiently at high voltage, which reduces the energy lost as heat due to resistance of the wire, transformed to a lower, voltage for use. Use of a higher voltage leads to more efficient transmission of power; the power losses in the wire are a product of the square of the current and the resistance of the wire, described by the formula: P w = I 2 R. This means that when transmitting a fixed power on a given wire, if the current is halved, the power loss due to the wire's resistance will be reduced to one quarter; the power transmitted is equal to the product of the voltage. Power is transmitted at hundreds of kilovolts, transformed to 100 V – 240 V for domestic use. High voltages have disadvantages, such as the increased insulation required, increased difficulty in their safe handling.
In a power plant, energy is generated at a convenient voltage for the design of a generator, stepped up to a high voltage for transmission. Near the loads, the transmission voltage is stepped down to the voltages used by equipment. Consumer voltages vary somewhat depending on the country and size of load, but motors and lighting are built to use up to a few hundred volts between phases; the voltage delivered to equipment such as lighting and motor loads is standardized, with an allowable range of voltage over which equipment is expected to operate. Standard power utilization voltages and percentage tolerance vary in the different mains power systems found in the world. High-voltage direct-current electric power transmission systems have become more viable as technology has provided efficient means of changing the voltage of DC power. Transmission with high voltage direct current was not feasible in the early days of electric power transmission, as there was no economically viable way to step down the voltage of DC for end user applications such as lighting incandescent bulbs.
Three-phase electrical generation is common. The simplest way is to use three separate coils in the generator stator, physically offset by an angle of 120° to each other. Three current waveforms are produced that are equal in magnitude and 120° out of phase to each other. If coils are added opposite to these, they generate the same phases with reverse polarity and so can be wired together. In practice, higher "pole orders" are used. For example, a 12-pole machine would have 36 coils; the advantage is. For example, a 2-pole machine running at 3600 rpm and a 12-pole machine running at 600 rpm produce the same frequency. If the load on a three-phase system is balanced among the phases, no current flows through the neutral point. In the worst-case unbalanced load, the neutral current will not exceed the highest of the phase currents. Non-linear loads may require an oversized neutral bus and neutral conductor in the upstream distribution panel to handle harmonics. Harmonics can cause neutral conductor current levels to exceed that of all phase conductors.
For three-phase at utilization voltages a four-wire system is used. When stepping down three-phase, a transformer with a Delta primary and a Star secondary is used so there is no need for a neutral on the supply side. For smaller customers only a single phase and neutral, or two phases and neutral, are taken to the property. For larger installations all three phases and neutral are taken to the main distribution panel. From the three-phase main panel, both single and three-phase circuits may lead off. Three-wire single-phase systems, with a single center-tapped transformer giving two live conductors, is a common distribution scheme for res
Inertial navigation system
An inertial navigation system is a navigation device that uses a computer, motion sensors and rotation sensors to continuously calculate by dead reckoning the position, the orientation, the velocity of a moving object without the need for external references. The inertial sensors are supplemented by a barometric altimeter and by magnetic sensors and/or speed measuring devices. INSs are used on vehicles such as ships, submarines, guided missiles, spacecraft. Other terms used to refer to inertial navigation systems or related devices include inertial guidance system, inertial instrument, inertial measurement unit and many other variations. Older INS systems used an inertial platform as their mounting point to the vehicle and the terms are sometimes considered synonymous. Inertial navigation is a self-contained navigation technique in which measurements provided by accelerometers and gyroscopes are used to track the position and orientation of an object relative to a known starting point and velocity.
Inertial measurement units contain three orthogonal rate-gyroscopes and three orthogonal accelerometers, measuring angular velocity and linear acceleration respectively. By processing signals from these devices it is possible to track the position and orientation of a device. Inertial navigation is used in a wide range of applications including the navigation of aircraft and strategic missiles, spacecraft and ships. Recent advances in the construction of microelectromechanical systems have made it possible to manufacture small and light inertial navigation systems; these advances have widened the range of possible applications to include areas such as human and animal motion capture. An inertial navigation system includes at least a computer and a platform or module containing accelerometers, gyroscopes, or other motion-sensing devices; the INS is provided with its position and velocity from another source accompanied with the initial orientation and thereafter computes its own updated position and velocity by integrating information received from the motion sensors.
The advantage of an INS is that it requires no external references in order to determine its position, orientation, or velocity once it has been initialized. An INS can detect a change in its geographic position, a change in its velocity and a change in its orientation, it does this by measuring the linear angular velocity applied to the system. Since it requires no external reference, it is immune to deception. Inertial navigation systems are used in many different moving objects. However, their cost and complexity place constraints on the environments in which they are practical for use. Gyroscopes measure the angular velocity of the sensor frame with respect to the inertial reference frame. By using the original orientation of the system in the inertial reference frame as the initial condition and integrating the angular velocity, the system's current orientation is known at all times; this can be thought of as the ability of a blindfolded passenger in a car to feel the car turn left and right or tilt up and down as the car ascends or descends hills.
Based on this information alone, the passenger knows what direction the car is facing but not how fast or slow it is moving, or whether it is sliding sideways. Accelerometers measure the linear acceleration of the moving vehicle in the sensor or body frame, but in directions that can only be measured relative to the moving system; this can be thought of as the ability of a blindfolded passenger in a car to feel himself pressed back into his seat as the vehicle accelerates forward or pulled forward as it slows down. Based on this information alone, he knows how the vehicle is accelerating relative to itself, that is, whether it is accelerating forward, left, right, up, or down measured relative to the car, but not the direction relative to the Earth, since he did not know what direction the car was facing relative to the Earth when they felt the accelerations. However, by tracking both the current angular velocity of the system and the current linear acceleration of the system measured relative to the moving system, it is possible to determine the linear acceleration of the system in the inertial reference frame.
Performing integration on the inertial accelerations using the correct kinematic equations yields the inertial velocities of the system and integration again yields the inertial position. In our example, if the blindfolded passenger knew how the car was pointed and what its velocity was before he was blindfolded and if he is able to keep track of both how the car has turned and how it has accelerated and decelerated since he can know the current orientation and velocity of the car at any time. All inertial navigation systems suffer from integration drift: small errors in the measurement of acceleration and angular velocity are integrated into progressively larger errors in velocity, which are compounded into still greater errors in position. Since the new position is calculated
In a fixed-wing aircraft, the spar is the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries the weight of the wings while on the ground. Other structural and forming members such as ribs may be attached to the spar or spars, with stressed skin construction sharing the loads where it is used. There may be more than one spar in a none at all. However, where a single spar carries the majority of the forces on it, it is known as the main spar. Spars are used in other aircraft aerofoil surfaces such as the tailplane and fin and serve a similar function, although the loads transmitted may be different from those of a wing spar; the wing spar provides the majority of the weight support and dynamic load integrity of cantilever monoplanes coupled with the strength of the wing'D' box itself. Together, these two structural components collectively provide the wing rigidity needed to enable the aircraft to fly safely. Biplanes employing flying wires have much of the flight loads transmitted through the wires and interplane struts enabling smaller section and thus lighter spars to be used at the cost of increasing drag.
Some of the forces acting on a wing spar are: Upward bending loads resulting from the wing lift force that supports the fuselage in flight. These forces are offset by carrying fuel in the wings or employing wing-tip-mounted fuel tanks. Downward bending loads while stationary on the ground due to the weight of the structure, fuel carried in the wings, wing-mounted engines if used. Drag loads dependent on airspeed and inertia. Rolling inertia loads. Chordwise twisting loads due to aerodynamic effects at high airspeeds associated with washout, the use of ailerons resulting in control reversal. Further twisting loads are induced by changes of thrust settings to underwing-mounted engines; the "D" box construction is beneficial to reduce wing twisting. Many of these loads are reversed abruptly in flight with an aircraft such as the Extra 300 when performing extreme aerobatic manoeuvers. Early aircraft used spars carved from solid spruce or ash. Several different wooden spar types have been used and experimented with such as spars that are box-section in form.
Wooden spars are still being used in light aircraft such as its relatives. A disadvantage of the wooden spar is the deteriorating effect that atmospheric conditions, both dry and wet, biological threats such as wood-boring insect infestation and fungal attack can have on the component. Wood wing spars of multipiece construction consist of upper and lower members, called spar caps, vertical sheet wood members, known as shear webs or more webs, that span the distance between the spar caps. In modern times, "homebuilt replica aircraft" such as the replica Spitfires use laminated wooden spars; these spars are laminated from spruce or douglas fir. A number of enthusiasts build "replica" Spitfires that will fly using a variety of engines relative to the size of the aircraft. A typical metal spar in a general aviation aircraft consists of a sheet aluminium spar web, with "L" or "T" -shaped spar caps being welded or riveted to the top and bottom of the sheet to prevent buckling under applied loads. Larger aircraft using this method of spar construction may have the spar caps sealed to provide integral fuel tanks.
Fatigue of metal wing spars has been an identified causal factor in aviation accidents in older aircraft as was the case with Chalk's Ocean Airways Flight 101. The German Junkers J. I armoured fuselage ground-attack sesquiplane of 1917 used a Hugo Junkers-designed multi-tube network of several tubular wing spars, placed just under the corrugated duralumin wing covering and with each tubular spar connected to the adjacent one with a space frame of triangulated duralumin strips — in the manner of a Warren truss layout — riveted onto the spars, resulting in a substantial increase in structural strength at a time when most other aircraft designs were built completely with wood-structure wings; the Junkers all-metal corrugated-covered wing / multiple tubular wing spar design format was emulated after World War I by American aviation designer William Stout for his 1920s-era Ford Trimotor airliner series, by Russian aerospace designer Andrei Tupolev for such aircraft as his Tupolev ANT-2 of 1922, upwards in size to the then-gigantic Maksim Gorki of 1934.
A design aspect of the Supermarine Spitfire wing that contributed to its success was an innovative spar boom design, made up of five square concentric tubes that fitted into each other. Two of these booms were linked together by an alloy web, creating a lightweight and strong main spar. A version of this spar construction method is used in the BD-5, designed and constructed by Jim Bede in the early 1970s; the spar used in the BD-5 and subsequent BD projects was aluminium tube of 2 inches in diameter, joined at the wing root with a much larger internal diameter aluminium tube to provide the wing structural integrity. In aircraft such as the Vickers Wellington, a geodesic wing spar structure was employed, which had the advantages of being lightweight and able to withstand heavy battle damage with only partial loss of strength. Many modern aircraft use carbon fibre and Kevlar in their construction, ranging in size from large airliners to small h
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows small electronic receivers to determine their location to high precision using time signals transmitted along a line of sight by radio from satellites; the system can be used for providing position, navigation or for tracking the position of something fitted with a receiver. The signals allow the electronic receiver to calculate the current local time to high precision, which allows time synchronisation. Satnav systems operate independently of any telephonic or internet reception, though these technologies can enhance the usefulness of the positioning information generated. A satellite navigation system with global coverage may be termed a global navigation satellite system; as of October 2018, the United States' Global Positioning System and Russia's GLONASS are operational GNSSs, with China's BeiDou Navigation Satellite System and the European Union's Galileo scheduled to be operational by 2020.
India and Japan are in the process of developing regional navigation and augmentation systems as well. Global coverage for each system is achieved by a satellite constellation of 18–30 medium Earth orbit satellites spread between several orbital planes; the actual systems vary, but use orbital inclinations of >50° and orbital periods of twelve hours. Satellite navigation systems that provide enhanced accuracy and integrity monitoring usable for civil navigation are classified as follows: GNSS-1 is the first generation system and is the combination of existing satellite navigation systems, with Satellite Based Augmentation Systems or Ground Based Augmentation Systems. In the United States, the satellite based component is the Wide Area Augmentation System, in Europe it is the European Geostationary Navigation Overlay Service, in Japan it is the Multi-Functional Satellite Augmentation System. Ground based augmentation is provided by systems like the Local Area Augmentation System. GNSS-2 is the second generation of systems that independently provides a full civilian satellite navigation system, exemplified by the European Galileo positioning system.
These systems will provide the integrity monitoring necessary for civil navigation. This system consisted of only Upper L-Band frequency sets. In recent years, GNSS systems have begun activating Lower L-Band frequency sets for civilian use; as of late 2018, a few consumer grade GNSS devices are being sold that leverage both, are called "Dual band GNSS" or "Dual band GPS" devices. Core Satellite navigation systems GPS, GLONASS, Galileo and Compass. Global Satellite Based Augmentation Systems such as StarFire. Regional SBAS including WAAS, EGNOS, MSAS and GAGAN. Regional Satellite Navigation Systems such as China's Beidou, India's NAVIC, Japan's proposed QZSS. Continental scale Ground Based Augmentation Systems for example the Australian GRAS and the joint US Coast Guard, Canadian Coast Guard, US Army Corps of Engineers and US Department of Transportation National Differential GPS service. Regional scale GBAS such as CORS networks. Local GBAS typified by a single GPS reference station operating Real Time Kinematic corrections.
Ground based radio navigation has long been practiced. The DECCA, LORAN, GEE and Omega systems used terrestrial longwave radio transmitters which broadcast a radio pulse from a known "master" location, followed by a pulse repeated from a number of "slave" stations; the delay between the reception of the master signal and the slave signals allowed the receiver to deduce the distance to each of the slaves, providing a fix. The first satellite navigation system was Transit, a system deployed by the US military in the 1960s. Transit's operation was based on the Doppler effect: the satellites travelled on well-known paths and broadcast their signals on a well-known radio frequency; the received frequency will differ from the broadcast frequency because of the movement of the satellite with respect to the receiver. By monitoring this frequency shift over a short time interval, the receiver can determine its location to one side or the other of the satellite, several such measurements combined with a precise knowledge of the satellite's orbit can fix a particular position.
Satellite orbital position errors are induced by variations in the gravity field and radar refraction, among others. These were resolved by a team led by Harold L Jury of Pan Am Aerospace Division in Florida from 1970-1973. Using real-time data assimilation and recursive estimation, the systematic and residual errors were narrowed down to a manageable level to permit accurate navigation. Part of an orbiting satellite's broadcast included its precise orbital data. In order to ensure accuracy, the US Naval Observatory continuously observed the precise orbits of these satellites; as a satellite's orbit deviated, the USNO would send the updated information to the satellite. Subsequent broadcasts from an updated satellite would contain its most recent ephemeris. Modern systems are more direct; the satellite broadcasts a signal that contains orbital data and the precise time the signal was transmitted. The
Electronic flight instrument system
An electronic flight instrument system is a flight deck instrument display system that displays flight data electronically rather than electromechanically. An EFIS consists of a primary flight display, multi-function display, an engine indicating and crew alerting system display. Early EFIS models used cathode ray tube displays; the complex electromechanical attitude director indicator and horizontal situation indicator were the first candidates for replacement by EFIS. Now, few flight deck instruments cannot be replaced by an electronic display. EFIS installations vary greatly. A light aircraft might be equipped with one display unit that displays navigation data. A large, commercial aircraft is to have six or more display units. Typical EFIS displays and controls can be seen at this B737 technical information web site; the equivalent electromechanical instruments are shown here. EFIS installation follows the sequence: Displays Controls Data processorsA basic EFIS might have all these facilities in the one unit.
On the flight deck, the display units are the most obvious parts of an EFIS system, are the features that lead to the term glass cockpit. The display unit that replaces the ADI is called the primary flight display. If a separate display replaces the HSI, it is called the navigation display; the PFD displays all information critical to flight, including calibrated airspeed, heading, vertical speed and yaw. The PFD is designed to improve a pilot's situational awareness by integrating this information into a single display instead of six different analog instruments, reducing the amount of time necessary to monitor the instruments. PFDs increase situational awareness by alerting the aircrew to unusual or hazardous conditions — for example, low airspeed, high rate of descent — by changing the color or shape of the display or by providing audio alerts; the names Electronic Attitude Director Indicator and Electronic Horizontal Situation Indicator are used by some manufacturers. However, a simulated ADI is only the centerpiece of the PFD.
Additional information is both arranged around this graphic. Multi-function displays can render a separate navigation display unnecessary. Another option is to use one large screen to show both navigation display; the PFD and navigation display are physically identical. The information displayed is determined by the system interfaces. Thus, spares holding is simplified: the one display unit can be fitted in any position. LCD units generate less heat than CRTs, they are lighter, occupy a lower volume. The MFD displays weather information from multiple systems. MFDs are most designed as "chart-centric", where the aircrew can overlay different information over a map or chart. Examples of MFD overlay information include the aircraft's current route plan, weather information from either on-board radar or lightning detection sensors or ground-based sensors, e.g. NEXRAD, restricted airspace and aircraft traffic; the MFD can be used to view other non-overlay type of data and calculated overlay-type data, e.g. the glide radius of the aircraft, given current location over terrain and aircraft speed and altitude.
MFDs can display information about aircraft systems, such as fuel and electrical systems. As with the PFD, the MFD can change the color or shape of the data to alert the aircrew to hazardous situations. EICAS displays information about the aircraft's systems, including its fuel and propulsion systems. EICAS displays are designed to mimic traditional round gauges while supplying digital readouts of the parameters. EICAS improves situational awareness by allowing the aircrew to view complex information in a graphical format and by alerting the crew to unusual or hazardous situations. For example, if an engine begins to lose oil pressure, the EICAS might sound an alert, switch the display to the page with the oil system information and outline the low oil pressure data with a red box. Unlike traditional round gauges, many levels of warnings and alarms can be set. Proper care must be taken when designing EICAS to ensure that the aircrew are always provided with the most important information and not overloaded with warnings or alarms.
ECAM is a similar system used by Airbus, which in addition to providing EICAS functions recommend remedial action. EFIS provides pilots with controls that enter data. Where other equipment uses pilot inputs, data buses broadcast the pilot's selections so that the pilot need only enter the selection once. For example, the pilot selects the desired level-off altitude on a control unit; the EFIS repeats this selected altitude on the PFD, by comparing it with the actual altitude generates an altitude error display. This same altitude selection is used by the automatic flight control system to level off, by the altitude alerting system to provide appropriate warnings; the EFIS visual display is produced by the symbol generator. This receives data inputs from the pilot, signals from sensors, EFIS format selections made by the pilot; the symbol generator can go by other names, such as display processing computer, display electronics unit, etc. The symbol generator does more than generate symbols, it has monitoring facilities
Flight instruments are the instruments in the cockpit of an aircraft that provide the pilot with information about the flight situation of that aircraft, such as altitude and direction. They improve safety by allowing the pilot to fly the aircraft in level flight, make turns, without a reference outside the aircraft such as the horizon. Visual flight rules require an airspeed indicator, an altimeter, a compass or other suitable magnetic direction indicator. Instrument flight rules additionally require a gyroscopic pitch-bank and rate of turn indicator, plus a slip-skid indicator, adjustable altimeter, a clock. Flight into Instrument meteorological conditions require radio navigation instruments for precise takeoffs and landings; the term is sometimes used loosely as a synonym for cockpit instruments as a whole, in which context it can include engine instruments and communication equipment. Many modern aircraft have electronic flight instrument systems. Most regulated aircraft have these flight instruments as dictated by the US Code of Federal Regulations, Title 14, Part 91.
They are grouped according to pitot-static system, compass systems, gyroscopic instruments. The altimeter shows the aircraft's altitude above sea-level by measuring the difference between the pressure in a stack of aneroid capsules inside the altimeter and the atmospheric pressure obtained through the static system, it is adjustable for local barometric pressure which must be set to obtain accurate altitude readings. As the aircraft ascends, the capsules expand and the static pressure drops, causing the altimeter to indicate a higher altitude; the opposite effect occurs. With the advancement in aviation and increased altitude ceiling, the altimeter dial had to be altered for use both at higher and lower altitudes. Hence when the needles were indicating lower altitudes i.e. the first 360-degree operation of the pointers was delineated by the appearance of a small window with oblique lines warning the pilot that he or she is nearer to the ground. This modification was introduced in the early sixties after the recurrence of air accidents caused by the confusion in the pilot's mind.
At higher altitudes, the window will disappear. The airspeed indicator shows the aircraft's speed relative to the surrounding air, it works by measuring the ram-air pressure in the aircraft's Pitot tube relative to the ambient static pressure. The indicated airspeed must be corrected for nonstandard pressure and temperature in order to obtain the true airspeed; the instrument is color coded to indicate important airspeeds such as the stall speed, never-exceed airspeed, or safe flap operation speeds. The VSI senses changing air pressure, displays that information to the pilot as a rate of climb or descent in feet per minute, meters per second or knots; the compass shows. Errors include Variation, or the difference between magnetic and true direction, Deviation, caused by the electrical wiring in the aircraft, which requires a Compass Correction Card. Additionally, the compass is subject to Dip Errors. While reliable in steady level flight it can give confusing indications when turning, descending, or accelerating due to the inclination of the Earth's magnetic field.
For this reason, the heading indicator is used for aircraft operation, but periodically calibrated against the compass. The attitude indicator shows the aircraft's relation to the horizon. From this the pilot can tell whether the wings are level and if the aircraft nose is pointing above or below the horizon; this is a primary instrument for instrument flight and is useful in conditions of poor visibility. Pilots are trained to use other instruments in combination should its power fail; the heading indicator displays the aircraft's heading with respect to magnetic north when set with a compass. Bearing friction causes drift errors from precession, which must be periodically corrected by calibrating the instrument to the magnetic compass. In many advanced aircraft, the heading indicator is replaced by a horizontal situation indicator which provides the same heading information, but assists with navigation; these include the Turn-and-Slip Indicator and the Turn Coordinator, which indicate rotation about the longitudinal axis.
They include an inclinometer to indicate if the aircraft is in Coordinated flight, or in a Slip or Skid. Additional marks indicate a Standard rate turn; these include Attitude Director Indicator. The HSI combines the magnetic compass with a Glide slope; the navigation information comes from a VOR/Localizer, or GPS. The ADI is an Attitude Indicator with computer-driven steering bars, a task reliever during instrument flight; the VOR indicator instrument includes a Course deviation indicator, Omnibearing Selector, TO/FROM indicator, Flags. The CDI shows an aircraft's lateral position in relation to a selected radial track, it is used for orientation, tracking to or from a station, course interception. On the instrument, the vertical needle indicates the lateral position of the selected track. An horizontal needle allows the pilot to follow a glide slope when the instrument is used with an ILS; the Automatic direction finder indicator instrument can be a fixed-card, movable card, or a Radio magnetic indicator.
An RMI is remotely coupled to a gyrocompass so that it automatically rotates
The cruciform tail is an aircraft empennage configuration which, when viewed from the aircraft's front or rear, looks much like a cross. The usual arrangement is to have the horizontal stabilizer intersect the vertical tail somewhere near the middle, above the top of the fuselage; the design is used to locate the horizontal stabilizer away from jet exhaust and wing wake, as well as to provide undisturbed airflow to the rudder. Avro Canada CF-100 Canuck British Aerospace Jetstream 31/32 British Aerospace Jetstream 41 Britten-Norman Trislander Canadair CL-215 Cessna A-37 Dragonfly Cessna Citation - Excel and Latitude variants only Cessna T303 Crusader Cessna T-37 Tweet Consolidated PBY Catalina Dassault Falcon 10/100 Dassault Falcon 20/200 Dassault Falcon 50 Dassault Falcon 5X Dassault Falcon 7X Dassault Falcon 8X Dassault Falcon 900 Dassault Falcon 2000 de Havilland Canada DHC-3 Otter Dornier Do 335 Douglas A-4 Skyhawk Fairchild C-26 Metroliner Fairchild Swearingen Metroliner Gloster Meteor Handley Page Jetstream Hawker Hunter Ivanov ZJ-Viera Lake Buccaneer Lockheed JetStar McDonnell FH Phantom McDonnell F2H Banshee - early variants only Messerschmitt 262 Mikoyan-Gurevich MiG-15 Northrop YC-125 Raider Piccard Eureka PZL Bielsko SZD-50 Puchacz Republic F-84 Thunderjet Republic F-84F Thunderstreak/RF-84F Thunderflash Republic XF-84H Thunderscreech Roberts Cygnet Rockwell B-1 Lancer Rockwell Commander 112/114 Scaled Composites White Knight Two Stratos 714 Sud Aviation Caravelle Swearingen Merlin US Aviation Cumulus Westland Whirlwind Pelikan tail T-tail Twin tail V-tail