Early combat aircraft of the First World War were often fragile contraptions not ideally suited to the rigors of sustained aerial maneuvering. In Britain, Herbert Smith of the Sopwith Aviation Company designed a new biplane based on an earlier design, the Sigrist Bus (named for the manager of the Sopwith factory, Fred Sigrist), that never went into production. In most contemporary biplane designs, the two upper wings were joined by a central section. Support struts attached to the upper longerons of the fuselage to the ends of the central section and usually a second set of struts were attached to the inner part of the outer wings connected to an outer set of longerons on the fuselage.

In the new two-seat Sopwith design, there was no central section and the two upper wings were joined together. A W-shaped set of struts supported the upper wing of the biplane to the fuselage longerons and were considered "one and a half set of struts" instead of two sets of struts, which led to the new Sopwith's name, the 1 1/2 Strutter. The one and a half strut layout gave the upper wing tremendous rigidity like a railroad trestle.

But more remarkably in the Sopwith 1 1/2 Strutter, it introduced two features that are now commonplace on modern aircraft.

The first innovation was a variable-incidence horizontal stabilizer. The front spar of the tailplane was hinged on the rear fuselage and a worm gear actuated by a set of cables linked to a handwheel in the cockpit allowed the pilot to adjust the trim of the entire stabilizer. At a neutral setting, the tailplane was angled +2 degrees and the worm gear allowed the pilot to move the entire assembly more or less from that neutral setting depending upon the flying conditions.

The other innovation on the 1 1/2 Strutter were airbrakes on the trailing edge root of the lower wing. Pivoted at about quarter chord on each side, the airbrakes were operated by another handwheel in the cockpit that linked to a set of cables that raised the airbrakes up to 90 degrees upward and could be locked into position by the pilot. As the 1 1/2 Strutter had relatively clean lines for the day, it had a flat gliding angle and high landing speed (most aircraft of the day didn't have flaps) and the airbrakes were used to assist with the descent and landing.

Source: Aeroplane Monthly, December 2009. "Aeroplane Database: Sopwith 1 1/2 Strutter" by Philip Jarrett, p56-70.

Warship in the Desert: The Muroc Maru

At the instruction of General Henry "Hap" Arnold, in 1933 Rogers Dry Lake in the Antelope Valley north of Los Angeles was chosen as a gunnery and bombing training range for the expanding US Army Air Forces. Set up six miles west of the town of Muroc by personnel from March Army Air Field in Riverside, a series of practice targets were set up throughout the dry lake bed site which included simulated structures, the outlines of naval ships for high level bombing practice, and even a track for a moving target. Retired elderly Keystone biplane bombers were set up as well on a simulated airfield. Two years after being established, a second site was set up on the dry lake bed just one mile north of the town of Muroc.

Initially needing only a caretaker group of 13 Army personnel, the Muroc bombing range operated as a branch of March Army Air Field and the size of visiting squadrons would result in groups of personnel of varying sizes temporarily taking up residence at Muroc. Not only bomber and attack squadrons passed through the range but fighter squadrons as well for ground strafing exercises. By the summer of 1941 the base had expanded considerably in anticipation of the coming war. By 1942 over 40,000 personnel were stationed at Muroc at any given time and this resulted in Muroc being established as an air base in its own right as Muroc AAF independent of March AAF.

One of the most unique targets at Muroc AAF was completed in March 1943 and was designated as "AAF Temporary Building (Target) T-799, a full-sized wooden mockup of a Japanese Atago-class heavy cruiser. It was made of wood and covered with chicken wire and tar paper. Over the tar paper it was covered with shredded chicken feathers to give the appearance of a solid warship. Constructed at the south end of Rogers Dry Lake, the target got the nickname "Muroc Maru" and cost the USAAF approximately $35,000, a hefty sum in those days for something to be used for target practice.

Sand berms were constructed around the Muroc Maru to simulate the bow wave and wake. Bomber crews practiced low-level skip bombing against the Muroc Maru. On particularly hot days, pilots reported that the mirage effect would give the appearance of the Muroc Maru sailing at sea. Due to the strong desert winds and temperature extremes, the chicken feather covering of the target wasn't as durable as the wood and chicken wire structure.

Flight testing of new aircraft began in 1942 at Muroc. Training activities ended at Muroc AAF in 1946 and with an independent US Air Force, it became Muroc AFB in 1948. The following year the base was renamed Edwards AFB.

As for the Muroc Maru, it was a declared a flight hazard and dismantled in 1950. Army engineers responsible for the dismantling weren't thrilled about the extent of unexploded ordinance in the structure of the target. Some of the sand berms remain at the site to this day as well as millions of nails and metal staples from the 1950 disassembly.

Source: X-Plane Crashes: Exploring Experimental Rocket Plane, and Spycraft Incidents, Accidents, and Crash Sites by Peter W. Merlin and Tony Moore. Specialty Press, 2008, p13-14.

On his very first combat mission in 1915 flying a two-seat FBA flying boat to attack German gunboats, the young Alexander de Seversky would lose his right leg. After recuperation, he was assigned as the chief naval aircraft inspector for the Russian Imperial Navy's Petrograd district which gave him an appreciation for the design and production of aircraft. He worked closely with Dimitry Grigorivich on a series of flying boats that resulted in the M-9, the first Russian-designed naval aircraft to go into production during the First World War. Seversky encouraged Grigorivich to incorporate a machine gun mount as well as armor plating for the crew on the M-9.

Despite losing his flying status due to his injury, Seversky managed to perform an aerobatic display in the M-9 that enraged his superiors but won him the admiration of Czar Nicholas II, who ordered Seversky placed back on flying duty. Fitted with a wooden prosthesis and flying the plodding M-9 flying boat (it only had a maximum speed of 69 mph), he managed to score four kills against German aircraft. In 1917 he started flying a Nieuport 21 biplane and scored his fifth and sixth kills by single-handedly downing a German bomber and its fighter escort, bringing him to ace status.

In 1918 his status won him assignment to Washington D.C. as the Russian military attache with the embassy, but the Bolshevik Revolution that year resulted in him staying in the United States for good. He served as an assistant to Brigadier General Billy Mitchell in Mitchell's crusade to advance the cause for air power and Seversky would eventually establish his own aircraft manufacturing firm, Seversky Aviation, in Long Island, New York. In 1939 amidst a corporate reorganization Seversky was voted off the board by his own company which was renamed Republic Aviation. Another Russian emigre who worked for Seversky, Alexander Kartvelli, would take one of Seversky's designs, the P-35A fighter, and develop it further along a series of subsequent designs that culminated in the Republic P-47 Thunderbolt.

When he died in 1974, Seversky would hold 100 aviation-related patents and had received the Exceptional Service Medal for his advisory work for the U.S. Air Force in the 1960s.

Source: Aviation History, March 2010. "The Making of a War Hero" by James K. Libbey, p54-59.

From the outset in the design of the Convair B-58 Hustler, the unique fuel/weapons pod carried underneath the sleek bomber was to be only one of a family of systems that were to be pod mounted as well- rather than have to develop different versions for different roles, different pods for different roles would be carried by "stock" B-58s. Some proposals were for air-launched ballistic missiles, others were for reconnaissance systems with cameras housed in the pod. There was even a proposal for a passenger-carrying pod. But many of these ideas never came to be.

But one system that did get flight tested was for an airborne side-looking radar that would allow a B-58 to get detailed radar imagery from stand-off distances. The first system to be built was the pod-mounted Hughes AN/APQ-69 radar system which first flew on a B-58 on 24 December 1959. The AN/APQ-69 was one of the largest airborne radar antennas ever flown with a 50-foot long antenna that took up all of a long square-section pod carried by the Hustler. Twenty-five test flights were made with the radar and it had a 10 foot resolution from 50 miles which was quite good for the technology of the day. However, the size and weight of the pod restricted the B-58 to subsonic flight and as the radar took up the entire pod, it couldn't be used to carry additional fuel as the fuel/weapons pods used by the SAC alert Hustlers. As such, the B-58 carrying the AN/APQ-69 was limited to only 3 hours' flying time, making it of limited usefulness. In addition, the bow wave from the blunt nosed pod hampered nose gear retraction and a 0.5G pushover after takeoff was necessary to "help" the nose gear retract.

A more advanced radar pod flew in 1961, this time it was a Goodyear AN/APS-73 radar- this time it was a SAR (synthetic aperture radar) which allowed for a smaller antenna but a more detailed radar picture and it was used in a pod that had the same cross-section as the MB-1 fuel/weapons pod already in use- this allowed the B-58 to use nearly all of its performance envelope and the pod could also carry a sizeable amount of fuel.

The AN/APS-73 was housed in a black fiberglass nose section of the pod with the aft 2/3 of the pod carrying fuel. There were two X-band rotating antennas in the pod nose that rotated on an axis that ran longitudinally the length of the pod. The radar range was about 80 miles and was flight tested under the code name Project Quick Check. While the system never went into production, it was used operationally on one flight during the Cuban Missile Crisis- a single B-58 flight carrying the AN/APS-73 was made to survey targets of interest on the island, making it the first and only flight of a B-58 Hustler into hostile airspace.

That particular aircraft, 55-0668, also was the same aircraft that flight tested the earlier Hughes radar pod. It survived the scrapping of the Hustler fleet in 1970 and is now on display at the Lone Star Flight Museum in Galveston, Texas.

Source: Convair B-58 Hustler: The World's First Supersonic Bomber by Jay Miller. Midland Publishing/Aerofax, 1997, p81-86.

The first Air Force air-refueling tankers were KB-29 and KB-50s converted from bombers but by the 1950s the Boeing KC-97 became the standard air refueling tanker- this choice, however, was not without its difficulties particularly in refueling the B-47 Stratojet- the KC-97 wasn't able to reach the higher altitudes where the B-47 was most efficient and the B-47 had to descend to lower altitudes where its fuel burn was higher in order to link up with the KC-97. Furthermore, even with the KC-97's throttles "firewalled", the Stratojet had a tendency to stall during the link up and as a result, the refueling operation would have to carried out with the KC-97 in a shallow dive in order to gain speed above the stall speed of the Stratojet.

In 1953, the USAF trialled two B-47Bs outfitted with the British probe-and-drogue system developed by Flight Refueling, Ltd. One aircraft designated YB-47F and nicknamed "Pa" was fitted with nose mounted probe and the other aircraft, designated KB-47G and nicknamed "Ma", reeled out the hose-mounted drogue from its bomb bay. On 1 September 1953 the pair made the world's first all-jet air refueling.

Despite the higher speeds and ease of rendezvous, the fuel transfer rate with the system wasn't fast enough and in certain conditions was actually *less* than the burn rate of the six J47 engines of the receiver Stratojet. Only the flying boom used on the KC-97 was capable of the fuel transfer rates needed to give the Stratojets "legs" to reach distant targets. The interim solution was to fit the KB-50 and KC-97 tankers with auxillary jet engines to provide extra speed during refueling but the long term solution would arrive in the form of the Boeing KC-135 Stratotanker that had the speed and altitude performance to match SAC's bomber fleet.

Source: Boeing's B-47 Stratojet by Alwyn T. Lloyd. Speciality Press, 2005, p202.

During the design of the first Lockheed U-2 spyplanes, designer Kelly Johnson held fast to his rule "one pound equals one foot of altitude" and if it wasn't completely necessary to the mission, it wasn't going on the aircraft. As a result, many of the navigational aids considered standard on most military aircraft were absent on the U-2. Central to the U-2's navigation equipment was the driftsight- a downward looking periscope that had two selectable magnifications. The circular driftsight dominated the center of the instrument panel on the U-2 until its replacement by GPS and glass displays in the 1990s. The driftsight give the pilot a 360-degree view underneath the aircraft and it was used for navigation in addition to sighting for the cameras.

If the ground wasn't visible due to overcast, dead reckoning was also used since the winds at the altitudes the U-2 operated were usually very light. The aircraft did have a radio compass, the AN/ARN-6, but on deep penetration flights of the Soviet Union, radio stations were far and few between.

A HF antenna system was planned for the U-2, allowing the pilot to tune into HF ground stations and determine his position by triangulation. Though tested successfully, the CIA realized that HF transmissions could betray the aircraft's position and the system, called System II, was dropped from the design.

The solution was to use the driftsight in combination with a specially-made sextant that was aligned with the driftsight's optical path. A mirror could be switched that diverted the view through the optical driftsight to the sextant unit that was mounted just ahead of the cockpit atop the nose. At the 50,000+ feet altitudes the U-2 operated, the sky was black as night even in midday and star fixes could be taken using the sextant coupled to the driftsight. Since the fully suited pilot wouldn't be able to compute the star fixes and positions during the mission, an essential crewmember to each U-2 mission was a flight-rated navigator who planned the star fixes and did all the calculations ahead of each mission. As the calculations were specific for a particular timeframe, it was essential that the U-2 takeoff within a prescribed window of time or the star fixes would have to be recalculated by the navigator.

Source: 50 Years of the U-2: The Complete Illustrated History of the "Dragon Lady" by Chris Pocock. Schiffer Publishing, 2005, p32.

During the development of the hydrogen bomb there were concerns by the USAF that the delivery aircraft wouldn't be able to successfully exit the target area after dropping the weapon. As the development of the Atlas ICBM was still years away, Project Brass Ring was initiated in 1950 to create an unmanned version of the Boeing B-47 Stratojet to carry the H-bomb which would be designated MB-47 which in turn would be controlled by a manned Stratojet designated DB-47.

North American Aviation developed a sophisticated navigation and flight control system for the MB-47- but given the Air Force's requirements that the system be fully automatic, jam-resistant, and be accurate, it pushed the technology of the day and by 1952 it had to be cancelled due to cost overruns. The USAF then turned to Sperry Gyroscope to pick up where North American left off and it eventually cost a then-hefty sum of $2.3 million to complete. The MB-47 made its first flight on 7 May 1952 and by that summer both the MB-47 and the DB-47 controller had made several test flights with encouraging results. However, the cost of Project Brass Ring had nearly doubled from $4.9 million to just over $10 million.

By this point in the program SAC had determined that the Convair B-36 Peacemaker would be able to deliver the first production H-bombs if they were equipped with a parachute-retarding lay-down system. Furthermore, gaining permission from NATO members to forward deploy Stratojets in the UK, Spain, and French Morrocco made Project Brass Ring unnecessary and the program was terminated in April 1953.

Source: Boeing's B-47 Stratojet by Alwyn T. Lloyd. Speciality Press, 2005, p206-207

It was in the late 1970s that analysts at Cessna realized that the vast majority of utility aircraft used in remote areas were either unsuitable for the role or were, in the case of the Douglas DC-3 and the De Havilland Beaver/Otter series, aging with no ideal replacement in the works. So on 20 November 1981 the Cessna Model 208 Caravan was launched, John Berwick, the chief engineer at Cessna's Pawnee Division in Wichita, Kansas, brought on board two men who were instrumental in design and development of the De Havilland Canada Beaver- the first individual was Russ Bannock, who first flew the Beaver on its maiden flight in August 1947 and later rose to De Havilland Canada's sales director after having demonstrated the Beaver worldwide.

The other addition was Dick Hiscocks who was the head aerodynamicist on the Beaver and later became De Havilland Canada's VP for engineering. Both Bannock and Hiscocks had recently retired from DHC and were brought in regularly to advise Cessna and review the program on a monthly basis. Two years after launch, the Caravan made its first flight on 9 December 1982.

At about the same time, Federal Express was looking at a small cargo aircraft as a feeder to replace trucks that were used to fly packages to/from small towns to larger feeder cities that transferred them to the larger jets in the cargo fleet. The founder and president, Fred Smith, initially wanted only twin-engined aircraft for the feeder role but was convinced by Cessna to a flying demonstration- Smith was sold and in 1985 ordered 30 Caravans featuring an underfuselage cargo pannier developed for Federal Express (but now offered to all Caravan customers). In their first six months of operation with the company, the Caravans had a 99 percent dispatch rate in over 2,000 hours flying time. FedEx also drove the development of a stretched Caravan, the Grand Caravan Model 208B which had four additional feet of fuselage for more cargo capacity. The first 208B went into service for the company in October 1986 and by 1996, the Caravan fleet had flown over 1 million hours for the company, by which point they had 300 Caravans in service. The 500th Caravan built would go to FedEx.

Source: The Legend of Cessna by Jeffrey L. Rodengen. Write Stuff Enterprises, 1998, p205-212.

When the Tupolev Tu-16 Badger and Myasishchev M-4 Bison were revealed to the public at the 1954 May Day Parade in Moscow's Red Square, the United States realized that the Russians now had high-performance jet bombers capable of delivering atomic bombs to US cities. The USAF, via the Rome Air Development Center in New York, had the previous year started a program with General Electric on using jammers to modify the radar echoes of coastlines, rivers and cities to confuse the mapping radars used on strategic bombers. With the Badger and Bison unveiled in 1954, the work with GE took on added urgency.

In cooperation with the Strategic Air Command, GE engineers ran a test called the "Baltimore Project" to determine the nature of radar returns coming from a large city. A SAC Boeing B-29 with an APS-23 bombing/navigation radar was fitted with a selectable attenuator and the B-29 would overfly Baltimore, Maryland at different directions and with the attenuator set at different levels. This way they could filter out all but the strongest radar echoes. Combined with ground surveys of the areas of the city that were the most radar reflective, it was determined that oil storage tank farms were the most reflective followed by railroad yards and then factory complexes.

The engineers at GE then came up with what was called the Distributed Area Jammer (DAJ) which was a simple repeater that fit into a cylinder six inches across and 14 inches long. Twenty prototype DAJs were built which were installed on telephone poles and powered by the local power grid. They estimated that each DAJ unit would cost about a thousand dollars.

Tests using the prototype DAJs were conducted on Cape Cod, Massachusetts to see if they could use the jammers to alter the radar echoes of the coastline, which they found was easily accomplished by spacing the DAJs in a grid pattern a mile apart from the next DAJ. It was also found that clustering the DAJs close together produced a false radar echo that looked like a major city.

As preparations for production began with the intent of protecting a limited set of potential targets, Congress got wind of the DAJ project and each senator and representative demanded that their constituents be protected with a DAJ network. As a result, the cost spiraled upward as the USAF found that the number of DAJs needed just to protect the Eastern Seaboard alone made the cost unfeasible. As a result, the DAJ program was cancelled and it never went into production.

Source: The History of U.S. Electronic Warfare, Volume II- The Renaissance Years, 1946-1964 by Alfred Price. The Association of Old Crows/Port City Press, 1989, p131-133.

Jet engine technology in the late 1940s was still immature enough that a jet-engined fighter often still lacked comparable range to a piston-engined fighter. As a result, both the USAF and US Navy saw the turboprop as the potential answer- the USAF hoped a turboprop fighter would offer a longer range and the US Navy was interested in the power of turboprop fighter to make takeoff from a carrier deck possible without a catapult. To evaluate the possibility, both branches agreed to fund an experimental turboprop fighter based on Republic's AP-46 design. The USAF would buy three and the US Navy would acquire a single example.

By 1951 the arrangement had changed to with only the USAF getting two AP-46 aircraft designated XF-84H. Although a development of the F-84F Thunderstreak, the XF-84H only had wing and canopy of the Thunderstreak with an all new fuselage and tail unit. A 5,580-horsepower Allison XT40 turboprop that drove via an 18-foot shaft a 12-foot three-bladed constant speed propeller. The Aeroproducts prop rotated at 3,000 rpm which meant that the blade tips traveled at Mach 1.18 and as such, created an immense amount of noise, leading to the XF-84H's name, the Thunderscreech. As the prop was constant speed, thrust was effected by adjusting the pitch of the prop.

With its first flight at Edwards AFB on 22 July 1954, it was immediately apparent the XF-84H had some serious flaws. Maximum deflection of the rudder was insufficient to counter the massive torque and p-factor of the supersonic prop. In addition, there were constant hydraulic problems, the elevator was limited in its pitch authority and the prop gearbox kept overheating.

But most famously, the XF-84H Thunderscreech was noisy. The supersonic prop blades were so loud that residents over 20 miles away from Edwards AFB filed noise complaints with the USAF! When the aircraft first taxied out under its own power and took off, the control tower crew often had to hide under their consoles shielding their ears. Any ground crew standing nearby often felt nausea and dizziness even with ear protection due to the Mach shockwaves from the prop blades.

As a result, Republic was banned from doing run ups on the flightline and it would have to be towed 7 miles away from the main ramp behind a ridge called "Rocket Hill" as it had rocket engine test stands in the area.

The second Thunderscreech arrived in May 1956 and was temporarily bailed to the US Navy in support of the VTOL tail sitting convoy fighter program as both the Lockheed XFV-1 and Convair XFY-1 used the same Allison XT40 turboprop engine. The last Thunderscreech flight was made on 9 October 1956 with cancellation following, much to the relief of the pilots, ground crew and most everyone at Edwards AFB!

Source: International Air Power Review, Volume 24 (Summer 2002). AIRtime Publishing, 2002. "Warplane Classic: Republic F-84, Thunderjet, Thundersteak, and Thunderflash" by David Willis, p124.