Jovair 4E Sedan

Of all the helicopters that have flown in the Swiss skies, the Jovair 4E Sedan is perhaps the least known. More than fifty years after its last flights, only a few still remember that four-seat aircraft with tandem rotors.

Origins

The origins of the Jovair 4E Sedan date back to the second half of the 1940s. At that time in the United States, various designers firmly believed that every American of the “middle-class” would have a helicopter in their garage for personal use in addition to the automobile. Examples of the models appeared at that period include: Aeronautical Product API 1 (1945), De Lackner Cloud-Duster (1945), Higgins EB-1 (1945), Hoppi-Copter (1945), Roteron X-100 (1945), Brantly B.1 (1946), Exel Helicopter (1946), Firestone GA-45 (1946), Hamilton Helicopter (1947), Safti-Copter X-502 (1947), Bendix Model K (1947), Jensen Model 21 (1948), Glenview Metal Product GMP-1 (1948), Haig HK-1. To this list should be added the JOV-3 designed by Dragoljub Kosta “Gish” Jovanovich (1916-1983) and Frank Kozloski (1916-2003).
“Gish” Jovanovich was an engineer of Serbian origins born in Kragujevac who emigrated to the United States in 1938. After extensive studies at Belgrade University, Columbia University and Ford Motor Company in 1940 he was among the first in the United States to receive a formal degree in aeronautical engineering from New York University specializing in autogiros and helicopters. He was one of he first to pioneer and teach the philophy of fail-safe design in aircraft which resulted in many original patents.
After graduating from Pennsylvania State University Frank Kozloski worked for a year at Westinghouse Electric Corporation, after which he too enrolled at New York University to study aeronautical engineering. Upon graduation Kozloski joined Frank N. Piasecki (1919-2008), who together with Harold Venzie in August 1940 started the P-V Engineering Forum (Piasecki-Venzie) in Philadelphia, which initially was nothing more than a group of fellow engineer friends who met in the evenings and on weekends to discuss ideas and projects in the field of mechanical engineering. At the urging of Frank N. Piasecki the members of the “P-V Engineering Forum” began to focus on problems related to the development of the helicopter, which at that time was still in the experimental stage, but to which a promising future was predicted.
The group therefore focused on the development and construction of a small experimental helicopter known as the PV-2.
Frank Kozloski met “Gish” Jovanovich at meetings of the P. V. Engineering Forum. Some of its members as we know in 1946 founded in Philadelphia Piasecki Helicopter Corporation chaired by Frank N. Piasecki.

The pioneers of Pennsylvania

Pennsylvania is rightly recognized as the "cradle of American rotary-wing aviation" for a variety of reasons.
In his small workshop carved out of the family farm in Radnor starting in 1928 Artur M. Young (1905-1995) began building the first remote-controlled helicopters models from which the famous Bell 47 helicopter was born. 
It was here that the first autogyros built by the Pitcairn Aircraft Company and Kellett Autogiro Company were built, tested and produced.
On October 28-29, 1938, the Franklin Institute in Philadelphia hosted the first meeting devoted to the rotary wing attended by many inventors and engineers pioneering the nascent helicopter industry.
The Eddystone-based Platt-LePage Aircraft Company built the Platt-LePage XR-1, the first helicopter built for the U.S. military.
“Gish” Jovanovich and Frank Kozloski during 1946 started their own business by founding Helicopter Engineering Research Corporation (HERC) based in Blue Bell, whose goal was to build and market the JOV-3, an experimental two-seater tandem-rotor helicopter.
The choice of this configuration was probably influenced by the success achieved by the PV-3, and the experience gained by the engineers in the P. V. Engineering Forum.
It’s worth remembering that in 1946, “Gish” Jovanovich designed the JOV-1, a two-seat aircraft with coaxial contra-rotating rotors and a tail rotor, although it never made it past the design stage.
The design and construction of the JOV-3 was carried on between 1946 and 1947. Apparently the first official news about the new aircraft was published in Aviation week magazine in the January 19, 1948 edition in the article entitled “The JOV-3 recently made its debut”.
Initially powered by a Lycoming O-235 engine delivering 74.5/100 kW/hp, later replaced with a 93/125 kW/hp Lycoming O-290, the JOV-3 registered NX9000H was successfully tested at Boulevard Airport near Philadelphia by George Townson, an experienced autogyro pilot. 

Press reports at the time indicate that had it been mass produced the helicopter would have been sold at a price of about $6,000 (later raised over the next few months to $10,000).
According to its designers, the two-rotor tandem configuration offered the following advantages:

• elimination of the tail rotor;

• two rotors spinning in opposite direction at higher speeds were easier to balance and weighed less than one with the same wing surface, required less maintenance, and produced less strain on the controls;

• without the anti-torque rotor the lifting capacity of the JOV-3 was 45 kg (100 lbs) higher;

• wider center of gravity travel, and thus greater ease of loading;

• ease of piloting;

Capable of carrying a payload of about 190 kg (420 lbs) the helicopter lent itself to a variety of uses. Among those envisioned were aerial crop spraying or dusting, pipelines and power lines patrol, aerial observation, mail transportation, and flight school.
The introduction of the JOV-3 apparently led to a change in the relationship between D. K. Jovanovich and the leadership of the Piasecki Helicopter Corporation.
An article published in the magazine Aviation Week on August 2, 1948, states that the latter contacted HERC for a possible exchange of patents and information. Although HERC pledged to share knowledge freely with any friendly and cooperative manufacturer, it did not enter into any negotiations with PHC because the latter company showed an unreasonably hostile attitude from the date of the first public flight of the JOV-3. Jovanovich further pointed out that "Any claim or insinuation that the JOV-3 infringes on a design patent of Piasecki's appears to be completely without foundation. The engineers and technical personnel employed by HERC possess academic and professional backgrounds that make them perfectly qualified to independently design and develop any type of rotary-wing aircraft and its components".
On December 27, 1948, Aviation Week magazine reported that work on the certification of the JOV-3 had been only minimally completed, to the extent of about 10 percent. The same article reported that D. K. Jovanovich would travel to Seattle to discuss the terms of a merger with Hoppi-Copter Inc. 
According to reports at the time if plans for the merger were approved, certification of the JOV-3 would be completed, at which point production of a small series of aircraft would follow in Seattle. The deal for some unknown reasons was not reached.
Seeking funding to pursue the JOV-3 certification program, in February 1949 HERC executives traveled to Texas where they met with members of the Kilgore, Longview and Gladewater Chamber of Commerce. However once more, the initiative failed to produce results.

McCulloch Motors Corporation makes its entrance

In 1949 the JOV-3 attracted the attention of American industrialist Robert Paxton “Bob” McCulloch (1911-1977), who was firmly convinced that the helicopter would be the real solution to traffic problems. Some historical records indicate that he undertook prototype development efforts in Detroit starting in 1943. 
“Bob” McCulloch came from a wealthy family. His grandfather John Irvin Beggs (1847-1925), was a businessman closely associated with the electric utility boom and regional rail and interurban trolley systems. Upon his death he left a substantial inheritance to his heirs, one of whom was indeed his grandson “Bob” McCulloch. 
The considerable sum received from his grandfather gave him the financial freedom to devote himself to two of his passions, racing boats and mechanics. 
After graduating from Sanford University in 1936 with a degree in engineering he founded McCulloch Engineering Company in Milwaukee, where along with a team of engineers he developed engines and compressors for aircraft and automotive applications.
In 1943 McCulloch Aircraft Corporation was created to produce 6,000 engines used on small unmanned aircraft used as flying targets produced by the Radioplane Company to train crews the U.S. Army Air Force during the end of World War II.
Foreseeing a future in light engine production, and since the Milwaukee manufacturing plant was now inadequate, in 1946 McCulloch Aircraft Corporation's operations were moved to Los Angeles. This region offered reduced production costs along with a certain availability of qualified personnel.

In addition to Bob McCulloch and his family, several employees with their families moved to the California city, where with an initial investment of about $1 million construction of a new plant completed as early as 1946 was begun. While waiting for it to be ready, old buildings adapted to house offices and facilities were used. Within about two months of establishment the first engines for lawnmowers and chainsaws was already in production, along with other basic items such as die-cast gas heaters.
In the same year McCulloch Aviation Corporation changed its name to McCulloch Motors Corporation. 
Following an evaluation Bob McCulloch decided to focus on products such as lawn mowers and chain saws. 
Using a new method of die casting McCulloch discovered that he could produce a chainsaw on his own that was better, lighter and cheaper than the others. It was so successful that within a few years the plant needed to be expanded.
In the spring of 1951 at McCulloch Motors Corporation plant, located at 9775 Airport Boulevard, across from Los Angeles International Airport, where approximately 1,600 people were employed, portable pumps and drills, ejector seats and much more were being manufactured in addition to chainsaws, with a monthly sales value exceeding the sum of one million dollars. 
To build a sense of community within the employees and highlights its achievements and promoting company values the company had its own magazine known as “Flywheel.”
In the 1950s Bob McCulloch founded McCulloch Oil Corporation, which was involved in oil and gas extraction, land development, and later geothermal energy.

The McCulloch MC-4

McCulloch Motors Corporation had the funds needed to certify the JOV-3. Given Bob McCulloch's interest in the helicopter “Gish” Jovanovich and Frank Kozloski in 1949 were hired to work on a new prototype known as McCulloch MC-4. 
For the development and construction of the first MC-4, McCulloch engineers built an almost complete set of jigs, molds, and patterns that were then used for the limited series production that followed. This equipment was used, for example, to build the panels that lined the fuselage, engine mounts and other fuselage components. 
Other jigs, molds, and tooling were developed for the construction of the blades and for the installation of gears and other transmission assemblies and subassemblies.

In early 1951, shortly before the prototype was ready for its first test flights, the Aircraft Division of McCulloch Motors was established. Separate facilities were made available to it to complete the development of the prototype for the purpose of obtaining certification by the Civil Aeronautics Administration.
The MC-4 was very similar in overall appearance to the JOV-3, although slightly larger and with two seats side by side rather than in tandem. The goals the designers set for themselves were low-cost production, easy maintenance, and functionality.
The first prototype registered N4070K was powered by a 123/165 kW/hp Franklin 6V4-165-B32 engine. It made its first test flight in the hands of test pilot Albert “Al” Bayer on March 20, 1951. Shortly thereafter, construction of the second prototype (N4071K) was started.

During that period, the team expanded with the addition of new personnel, some of whom came from Piasecki and Hughes — including Al Bayer, who joined full-time in August 1951.
Between May and October 1951 D. K. Jovanovich filed several patents with the U.S. Design Patent Office. These included, for example, a new method of manufacturing rotor blades and an articulated hub that became fundamental to this and other later designs. These two patents appear never to have been sold but licensed to other manufacturers, and may probably have been his greatest achievements. 
In October 1951 the MC-4 made its first public appearance at Los Angeles International Airport. 
In September 1952 Bayer made several test flights in Palm Springs. As sales manager he was responsible for publicizing the virtues of the new aircraft by preparing a color brochure.
That same month two MC-4s entered the Civil Aviation Authority (CAA) program for obtaining civilian certification. Test flights by CAA personnel took place in the region of Palm Spring and continued until November 1952.
The MC-4 was awarded CAA Type Certificate 6H3 on February 17, 1953, making it the first tandem-rotor helicopter to be officially certified.

During the ceremony, Russell E. Cage, general manager of the Aircraft Division, naturally talk of the prospects of soon obtaining a contract with the Army and/or Navy for mass production of the new aircraft. Gage stated that the company was ready to evaluate and plan, and later gear up to begin production as soon as orders from the military services and private operators came in. At the end of the ceremony everyone went home happy and satisfied that their efforts had finally been recognized and appreciated. However, the enthusiasm dampemed within a few months.
Despite plans to begin production by the end of 1953, McCulloch acknowledged in the April issue of Flywheel magazine that operating costs remained too high to market the aircraft for civilian use without additional modifications. At that time the Aircraft Division, which employed about sixty people, half of whom were administrative employees, while the other were technical personnel (engineers, mechanics, welders, etc.) was working on the design and construction of three new models, namely: 

• MC-9 a single-seat “helicopter pilot trainer” helicopter;

• MC-10 a cargo helicopter with tandem rotors;

• MC-11 a collapsible radio controlled helicopter developed to answer a primary need for battlefield illumination. During the process of development, however, many additional uses of the MC-11 became apparent as for example: television and aerial photo reconnaissance, delivery of ammunition and supplies to isolated troops;

Considering the modern use of drones in warfare, the MC-11 represented a remarkable step forward. In late 1952 Bayer discussed with the engineers the challenges of integrating an autopilot system into a helicopter. In response they suggested a radio-controlled attack helicopter.

Among the various activities the Aircraft Division planned to pursue were the development of new rotor blades and several programs aimed at improving stability, structures, and performance of the aircraft.

Helicopters for the U.S. Navy and U.S. Army

Although it was designed primarily for commercial and private use the aircraft somehow captured the interest of the U.S. Navy and U.S. Army. 
The latter according to a report corralled by Al Bayer were looking for, among others, an easy-to-maintain two-seater aircraft for reconnaissance tasks.
The Naval Bureau of Aeronautics (BuAer) therefore signed a contract for the supply of two prototypes similar to the MC-4 (Bu. 133817 – n/s 1001 and 133818 – n/s 1002), which were delivered to the Naval Air Station Patuxent River (Maryland). There, the MC-4Cs underwent an initial series of evaluation tests in view of a possible operational use. In this context, Bayer and several engineers made themselves available to assist Navy pilots and engineers.
Designated XHUM-1, they were slightly larger than the MC-4 and could be identified by their two elliptical vertical stabilizers. The original engine was replaced with the more powerful Franklin 6A4-200-C32, delivering 149/200 kW/hp instead of 123/165 kW/hp. The rotor blade length was increased by 10 inches. These modifications led to the designation MC-4C.

Here are some excerpts from an evaluation report prepared at the end of test flights made at the Naval Ait Test Center at Patuxent River from June 3 to 26, 1953:
“The McCulloch MC-4C satisfactorily met the aerodynamic and structural requirements set for in the contract dated September 3, 1952. The aerodynamic maneuvres were completed with relatively large margins of control movement available. The rearward flight velocity was restricted because of the blanking effect of the rotors. The minimum rotor RPM never decreased below 80 percent of minimum operating rotor RPM and quickly returned to normal operating RPM when proper collective pitch was applied. No specific undesiderable characteristics were brought out in this demonstration”.
Both models have been preserved. According to information provided by Pima Air Museum, Bu. 133817 made its last flight on February 12, 1954 after completing just 68 hours of flight time. It was discharged from service on August 25, 1955.
The second MC-4C Bu. 13318 is displayed at Yanks Air Museum in Chino, California, where it underwent restoration between 2007 and 2011 was also decommissioned on the same day. 
The Army in turn acquired three aircraft that were designated YH-30. These were 52-5837 (s/n 1003), 52-5838 (s/n 1004) and 52-5839 (s/n 1005) which differed from each other only in minor details. 
Various sources consulted indicate that the reason for the failure of the XH-30/XHUM with the armed forces was that it was underpowered and mechanically too complex.
The MC-4C version as indicated earlier was driven by a more powerful engine (149/200 kW/hp) than the original version (123/165 kW/hp). The power-to-weight ratio was therefore comparable to other contemporary light aircraft such as the Bell 47G or the Hiller UH-12B purchased in large numbers by the U.S. military.

For sale

In a letter sent to Kellett Aircraft Corporation dated September 16, 1953, Al Bayer, who had previously worked for this company, informed vice-president as well as chief engineer Charles A. Barnett that McCulloch's Aircraft Division business was up for sale. Over the next few months there was an exchange of correspondence between the two from which emerged, at least in part, what were some of the weaknesses of the MC-4C found by the military during testing. Here are some considerations: “We have spent some time studying the five McCulloch reports we obtained on load from the Army Ground Forces. One reason for this study was to attemp to find some uncomplicated way of increasing hovering and climb performance without the complication of a larger engine. This preliminary investigation has turned up several interesting matters. For one thing we find that by using normal performance calculation methods that the hovering performance you would expect from the existing machine is considerably better than is reported by the McCulloch report covering the flight test for the MC-4C. This discrepancy suggests that it would be interesting to take the observed performance in hovering and to work backward to determine the overall power efficiency of the installation. In doing this we have tentatively established that the power efficiency is only 85%. We believe that this is a significant figure and that is may indicate a fundamental fault in the design. It seems that the belt transmission as presently designed may be fundamentally inefficient and may be slipping in operating or else it may be that the slip clutch is introducing a large power loss (author’s note - one of the drawbacks of belt drives transmissions is power loss caused by the significant friction between the belts and pulleys. Additionally, as the temperature rises, the belts tend to elongate, which can lead to the unwanted issue of slippage).
Al Bayer, who made many flights on this aircraft, stated that the configuration with tandem rotors was indeed too complex for such a small aircraft.
Perhaps for this reason, the YH-30s were rejected, and the three aircraft purchased for evaluation were almost immediately decommissioned. 
The YH-30 52-5837 is preserved at U.S. Army Aviation Museum at Fort Rucker, Alabama.

Even before knowing the outcome of the tests conducted by the US Navy and the US Army, McCulloch’s top management decided not to invest any further funds in the helicopter development program. The military’s decision to abandon the acquisition of the MC-4C — probably the only viable chance to start full-scale production — ultimately determined its outcome.
At that point, the company’s executives were well aware that sales in the civilian market alone would not be enough to secure the future of the MC-4C and the other ongoing projects. Unfortunately, it is unclear whether there was any genuine interest from civilian operators — something that seems rather unlikely. During the same period, the company also faced internal challenges, as a group of employees initiated a labor dispute.
In addition to the Kellett Aircraft Corporation, between late 1953 and early 1954, Al Bayer was tasked with identifying potential buyers. He sent letters to numerous countries, including Germany, Mexico, and Japan, and identified around 35 potential clients. A couple of companies showed specific interest in manufacturing the rotor blades. However, due to financial difficulties, the military’s lack of interest in the MC-4C, and the costs associated with the desired modifications, the acquisition of the MC-4C and the other ongoing projects and activities by the Kellett Aircraft Corporation did not take place.
Al Bayer continued to work at McCulloch as director of sales, service and flight operations until August 1954. He then became director of customer relations at Southern California Corporation in Ontario, after which he joined Hughes Tool Company as executive assistant on August 1, 1956.
In December 1954, when McCulloch Aircraft Division was dissolved, 'Gish' Jovanovich was hired as an engineer by the Aircraft Division of the Hughes Tool Company. There, he played a key role in the development of the Hughes 269 prototype, which the Hughes Tool Company began to work on in September 1954, following a market survey commissioned to Stanford Research to determine exactly what types of aircraft civilian and military operators truly needed.
Bob McCulloch focused again on outboard motors for boats and other activities, but as we shall see later, he did not abandoned the idea of a rotary-wing aircraft for civilian use.

1957 - Jovair Corporation

After the launch of the Hughes 269 project, Jovanovich and Kozloski left Hughes and founded Jovair Corporation in Culver City — a subsidiary of Jovanovich & Associates — with the goal of continuing their work in the field of rotary-wing aviation.
In that period they designed a two-seat autogyro designated Jovair J-2.
Development was slow because the company lacked personnel and financial resources. The prototype registered N4068K made its first flight at Culver City in June 1962. In April 1968 McCulloch Corporation announced that it had purchased for an unspecified sum a substantial interest in Jovair Corporation, whose name changed again to become McCulloch Aircraft Corporation.
In an interview with Vertifite magazine journalist Jovanovich stated that "We now have the necessary funds to begin production of our two new aircraft. Production of the autogyro is scheduled to begin next fall." 
Robert McCulloch became president of the new company, while D. K. Jovanovich was named vice-president. McCulloch became interested in the J-2 and continued its development under the new designation McCulloch J-2. The aircraft obtained certification from the FAA in May 1970 and was manufactured in series in about one hundred examples, the first of which was delivered in April 1971.

Jovair 4E Sedan

In the hope of changing the fate of the MC-4C, which by then seemed all but sealed, Jovair Corporation reacquired the design and manufacturing rights and purchased the second aircraft manufactured (N4071K), which was modified and converted into a four-seat aircraft. This gave rise to the Jovair 4E Sedan, which was very similar to its predecessor, although it could be easily distinguished by its four doors.
The original engine was swapped out for a more powerful Franklin 6A-350, producing 157/210 kW/hp at 3,100 rpm.
The aircraft received FAA certification in March 1963.

Besides N4071K, two additional units were manufactured: N6570C and N4091K. 
In the autumn of 1963, Jovair announced the release of the 4A version, a two-seat side-by-side stripped-fuselage model designed for agricultural, training, or utility operations. The useful load was increased to 435 kg (960 lbs), significantly higher than that of other 2-3 seat helicopters. In agricultural use, it could carry 300 liters (80 gallons) of insecticides in a single tank, which were dispersed through two folding spray booms mounted on the sides of the fuselage. 
The company also offered the 4ES version with a turbocharged 168/225 kW/hp Franklin 6AS-335 engine.

According to an article appeared on May 30, 1963, in The Aeroplane and Commercial Aviation News, the production of the Jovair 4E Sedan was intended as follows: component manufacturing would be assigned to selected subcontractors in the Southern California region, while final assembly would occur at Jovair Corporation’s facility in Culver City, where test flights prior to delivery were also scheduled. Sales were to be handled through dealers capable of providing service and maintenance.
According to Jovanovich, the Jovair 4E Sedan, offered at a much lower price than competing helicopters, would achieve broad market acceptance and enjoy popularity.
In the fall of 1963, Jovair introduced the 4A model, which had two side-by-side seats and a stripped-down fuselage. To reduce weight as much as possible and boost the payload capacity to 435 kg (960 lbs)—significantly higher than other contemporary 2- to 3-seat helicopters—all the side panels were removed. In agricultural use it could carry 300 liters (80 gallons) of insecticides in a single tank that were dispersed through two folding spray bars.
In that period Jovair tested a stabilization system to enable its helicopters to perform instrument flights.
The Jovair 4E, similar to the earlier MC-4, ultimately did not fulfill the hopes placed upon it. 
The helicopter was renamed McCulloch MC-4E in 1969, but by that time the prospect of mass production was definitively compromised.

Civilian employment

Apparently the MC-4E Sedan didn’t found any employ in the civilian sector. The few produced were mainly used for demo flights. One possible exception might have been the operator Charter Air Ltd in Los Angeles, which is reported to have used one.

Technical features

Listed below are the technical characteristics of the Jovair 4E Sedan published in a manufacturer's brochure.

Rotors and transmission system

Lift, in the Jovair 4E Sedan, is produced by a rotor system consisting of two fully articulated counter-rotating rotors with conventional push-pull tubes, bell crank, chains and cable control systems from the rotor hubs to the cockpit.
The rear rotor is elevated above the level of the front rotor so that in forward flight it is not affected by the front rotor downwash. 
Blades are built up of an aluminum extrusion and wrap-around skin, bonded together to form fail-safe structures, and were intercheangeable. Aerofoil section NACA 0015, constant chord of 17.2 cm (6.76’). Each rotor has a disc area of 69.77 sq meters (751 sq ft). The rotor blades are foldable.
The entine power transmissions unit consists of an over-running clutch, vee-belt central drive, drive shaft, and two right-angle gear reduction units. 

The central drive receives its power through a horizontal drive shaft from the engine which drives the lower vee-belt pulley. Twelve vee-belts carry the power from the lower vee-belt pulley to the upper vee-belt pulley. The rotors are engaged by hand crank located on the ceiling of the cockpit. 
The upper pulley contains a free-wheeling unit which allows autorotation of the rotors in the event o a power-plant failure. In powered flight the rotors turn at a speed between 442 and 508 rpm.
Power is transmitted from the upper vee-belt drive pulley to the right-angle gear reduction units by means of light aluminum shafting of approximately 7,6 cm (3-inch) diameter. There is one supporting bearing at the center of this shaft and all components of this system, including the engine, are interconnected to one and another through self-aligning couplings. All parts of the trasmission system are aligned either horizontally or vertically to she ship’s centerline and all points of power transmission are at right angles to each other.
The transmission gears are at either end of the drive shaft just below the rotors. They consists of right-angle, aircraft quality, spiral bevel gears, of 4.44 to 1 radio. They are housed in cast aluminum gear boxes designed for splash lubrication as well as for simple, external oil coolings by recirculation system. All bearing in the transmission system, with the exception of those in the gear cases, are sealed bearing lubricated for the bearing life.

Fuselage

Welded steel-tube structure covered with light aluminum service panels individually removable which provide easy access to all components. Factory built assemblies could be installed in minutes by line mechanics with standard tools, thereby eliminating usual long down-time of major overhauls. Two small fixed vertical fins assure directional stability.

Landing gear

Conventional tricycle gear consisting of two supporting V struts with axles and oleo struts extending from the fuselage outboard to the base of the axle fittings. A full swiveling cantiveler-type nose wheel is provided at the forward end of the fuselage. Goodyear wheels and tires. Provision for fitting skids or floats. Toe operated brakes and parking brakes.

Power plant

One 210/157 hp/kW Franklin 6A-350 six-cylinder horizontally-opposed air-cooled engine mounted horizontally just aft of the baggage compartment and forward of the vee-belt central drive section.

The engine can be removed as a package without disturbing other components. 
The engine is air-cooled by fan at the rear of the engine. The fan receives cooling air from an opening at the top of the fuselage just below the rear rotor pylon. 
The carburator cold air is supplied by a duct connecting the carburator with air scoop and filter located on the left-hand side of the fuselage. Carburator hot air passes through exhaust head exchangers. The exhaust manifolds are of stainless steel and include exhaust silencers.

The engine is mounted on standard vibration absorbers. The fuel system has gravity feed. The fuel tank has a capacity of 35 USG (132 litres), 91/98 octane. Oil capacity 2 US gallons (7.5 litres). The accessory section consists of an electric starter/alternator, two magnetos and carburator.

Accomodation

The cabin accommodate four occupants arranged in two rows. The pilot sits on the right. Access is provided by four doors, two on each side of the cabin. Optional dual controls. The front compartment is largely enclosed by transparent plexiglas panels.

Weights and dimensions

The Jovair 4E Sedan has an empty weight of about 664 kg (1,463 lb), while the maximum takeoff weight is 1'043 kg (2,300 lb). The payload is 380 kg (837 lb).
Rotor diameter 7.01 m (23 ft); fuselage length 5.49 m (18 ft); maximum fuselage width 1.30 m (4 ft 3'); maximum fuselage height 1.62 m (5 ft 4'); height 2.82 m (9 ft 3’); single rotor disc area 69.77 sq m (751 sq ft); rotor spacing 4.88 m (16 ft).

Optional equipment

Although mentioned in a few older aviation magazine articles, whether Jovair Corporation ever produced optional equipment other than dual controls remains uncertain.

Performance

The following table shows the performance of the Jovair 4E Sedan:

The Jovair 4E Sedan in Switzerland

After a failed attempt to start mass production in the United States, Jovair Corporation sent the model registered N4071K to Europe.
The last effort to initiate series production came from Farner Flugzeugbau AG, a small Swiss firm established by Willi Farner in Grenchen. Swiss aviation journalist Guido E. Bühlmann wrote in an article published in the magazine Skynews in October 2005 that the construction plans and documentation supplied with the aircraft however were incomplete to start a production under licence.
On November 26, 1970 at Grenchen Airport, Heliswiss chief pilot Walter Demuth, who had more than 4,000 hours of flight experience on helicopters under his belt, made some test flights. On June 12, 1971 again in Grenchen he made a 35-minute demonstration flight.

When questioned by the author about the outcome of those tests he stated that with 4 people on board and half fuel tank, however, the helicopter could barely hover in ground effect. “Die Maschine war einfach zu schwach” he stated, which literally translated means the aircraft was simply too weak, meaning that the power provided by the engine was insufficient to imagine its use in mountainous territory such as Switzerland. 
For these and other reasons Farner Flugzeugbau AG gave up its plans. The Jovair 4E N4071K was sold to a Swiss citizen and ended up in a warehouse for a long time.