Crown Supercoach

Crown Supercoach
1977-1991 Supercoach (retired) at a UK bus rally
Overview
Manufacturer	Crown Coach Corporation
Body and chassis
Doors	Single-door
Floor type	High-floor
Chassis	Crown Coach; underfloor or rear engine Single or tandem rear axles
Powertrain
Engine	Gasoline Hall-Scott Waukesha International Harvester Ford Super Duty Diesel Cummins Detroit Diesel Caterpillar
Capacity	72-97
Power output	210-335 hp
Transmission	4-speed automatic 6-speed automatic 5-speed manual 10-speed manual
Dimensions
Length	35-40 feet
Width	96 inches
Chronology

The Crown Supercoach is a bus that was constructed and marketed by Crown Coach Corporation from 1948 to 1991. While most examples were sold as yellow school buses, the Supercoach formed the basis for motorcoaches and other specialty vehicles using the same body and chassis. While technically available outside of the West Coast, nearly all Crown school buses were sold in California, Washington State, and Oregon.

From 1948 to 1984, the Supercoach was constructed at the Crown Coach facilities in Los Angeles, California; from 1984 to the 1991 closure of the company, the Supercoach was constructed in Chino, California.

Design History

1932-1948

In 1932, Crown Motor Carraige Company built its first complete school bus, in a shift from building bus bodies on cowled truck chassis.^[1] Externally modeled after Twin Coach body designs,^[2] the school bus body used a front-engine layout, with the Waukesha gasoline engine positioned next to the driver.^[1] The body was of all-metal construction with an integrated chassis and safety glass;^[2][3] for braking, in addition to the standard hydraulic service brakes, the Crown bus was equipped with a redundant hand-operated system alongside the standard parking/emergency brake.^[1]

From 1932 to 1935, Crown Body and Coach Corporation produced additional forward-control school buses. As the original 1932 design proved too expensive to produce on a large scale, Crown shifted to a design based on a Reo commercial truck chassis.^[1] Named the Metropolitan, while still a front-engine bus, the new design significantly decreased forward visibility.^[2]

In 1935, Crown revisited the 1932 design, introducing a new version as the first Crown Supercoach. With a seating capacity of up to 76 students,^[2] it was one of the largest school buses ever produced at the time. As with its 1932 predecessor, the 1935 Crown Supercoach featured an all-steel body with an integrated chassis, safety glass, and a front-engine body. In a big change, the redundant braking system was redesigned, with the Supercoach featuring full air brakes.^[2][3]

In 1936, Crown produced the Supercoach as an intercity motorcoach, featuring onboard sleeper compartments. To maximize interior room, the powertrain layout was changed from front-engine to an underfloor mid-engine configuration.^[1] In several variants, the Crown Supercoach would retain an underfloor layout through its 1991 discontinuation. In 1937, Crown would build the first mid-engine school bus, with a Hall-Scott gasoline engine; the change expanded capacity to 79 passengers.^[1][2][3] To provide proper engine cooling, the bus was fitted with a front-mounted radiator.

In 1940, Crown Coach redesigned the Supercoach bus body and chassis, moving the engine to the rear.^[2] Featuring a wider and taller interior, the Supercoach gained additional emergency exits (a rear exit window and right-side emergency door),^[2] following the standardization of school bus dimensions and exits in 1939.

During World War II, Crown Coach produced few vehicles, with all production diverted towards military use.^[1][2][3] In late 1945, Crown resumed production of Supercoach school and coach buses, struggling to meet demand.^[1] To better ensure its survival after the war, Crown entered a joint venture with Indiana school bus manufacturer Wayne Works, becoming the West Coast distributor of its product lines.

1948-1960

Late 1950s Crown Supercoach (restored)

In 1946, Crown began development on an all-new Supercoach. Starting life as a sightseeing bus for a motorcoach customer, the new-generation Supercoach entered production in 1948, with Crown producing its first school bus example in late 1949.^[1][3]

In a move back to the mid-engine layout, the design of the 1950 Crown Supercoach would break many precedents in school bus construction. Although built on a steel frame, to fight corrosion, the body panels of the Supercoach were of aluminum.^[1] In place of the traditional ladder truck-style frame, the Supercoach featured a monocque-style integrated frame.^[1]

In the early 1950s, Crown made several additions to the Supercoach model line. In 1951, the Crown Firecoach fire engine was introduced, heavily based on the mid-engine chassis of the Supercoach bus. At the same time, Crown began to explore other uses for the Supercoach; in 1954, several Crown Cargo Coach "brucks" were produced, combining the front body of a bus with the rear body of a van trailer.^[1][2] Crown Security Coaches came into use as prison buses throughout the West Coast.^[2]

In 1954, Crown introduced the first diesel-powered school bus, introducing the 743 cubic-inch Cummins NHH220 as an option.^[2] For school districts with growing student populations, Crown introduced a tandem rear-axle Supercoach in 1955. Expanding the seating capacity from 79 to 91 (with a later option for 97), this would become the highest-capacity school bus ever mass-produced (alongside similar Gillig Transit Coach DT-models)^[2][3]

To increase braking power, in 1956, Crown standardized 10-inch wide brake drums on all vehicles, the largest in the bus industry at the timesob.^[2] swere wiy

1960-1977

Retired 1960s Crown Supercoach in Mexico

In 1960, the body of the Crown Supercoach underwent its first set of modifications since its introduction in late 1949. To enhance visibility, the windshield, driver window, and entry door windows were redesigned. To make the bus more visible, Crown moved the taillamps and brakelights from the doors of the luggage compartment towards the rear corners of the body.

Although overtaken by school bus production, Crown continued production of the Supercoach as an intercity coach in various lengths.^[1] Designed similar to a GM Buffalo bus, the longest versions featured a raised deck over the luggage compartment; Crown also produced a bilevel coach similar to the GMC Scenicruiser in configuration.^[1][3]

During the 1960s, Crown began to further expand its engine line. To aid the performance of its 91-passenger buses, a 262 hp turbocharged Cummins NHH was added. Alongside the Cummins diesel, an additional option included an underfloor version of the Detroit Diesel 671. In 1973, the 743 cubic-inch Cummins NHH diesel was replaced by the 855 cubic-inch NHH diesel, requiring internal structural updates to the frame. From the outside, 1973-1977 Crown school buses are distinguished by flat-topped wheel wells.

1977-1991

1978 Supercoach 90-passenger

During the 1977 model year, federal regulations took effect that forever changed school bus design in the United States. To better protect passengers from crashes and rollovers, the structures of many school buses had to be updated; the metal-backed seats seen for decades were replaced by thickly padded, taller seats. Aside from the redesign of the passenger seats, which lead to minor capacity reductions, the structure of the Supercoach needed relatively few changes to meet the new regulations; the company had gone on to claim that the Supercoach was compliant as far back as 1950.^[4] Post-1977 Supercoaches are distinguished by larger pillars behind the drivers' window and entry door as well as the fixed window next to the side emergency door.

In the late 1980s, along with the Crown Supercoach Series II, Crown began to expand the Supercoach lineup beyond its traditional two models. In 1988, a 38' version (84-passenger) was introduced. In 1989, two new 40' versions were introduced: a rear-engine and a single rear axle mid-engine.

The Supercoach would outlive the Series II, ending production as Crown Coach closed its doors in March 1991.

Supercoach Series II

1989-1991 Crown Supercoach Series II

The Crown Supercoach Series II was introduced during 1989 during an effort to fit the Crown Supercoach with a methanol-fueled version of the Detroit Diesel 6V92. While the chassis accepted the V6 engine, it came at a cost, requiring significant modifications to the engine compartment to fit properly. However, Crown Coach saw this as the first opportunity to update the Supercoach school bus since it entered production in 1949. To minimize overall production costs, the body between the entry door and rear seats was common to the previous-generation Supercoach, which remained in production. The Series II was given a new driver's compartment (with an all-new instrument panel), new bodywork for the roof, rear compartment, and a flat-glass windshield.

Along with the methanol-fuel Detroit Diesel 6V92, the Series II became available with Cummins C8.3 and Caterpillar 3208 diesels in 40-foot rear-engine configurations. The Detroit Diesel 671 was fitted in 38-foot and 40-foot mid-engine units. During the 1990s, virtually all of the 6V92 units were converted from methanol to diesel.

Outlived by its predecessor, the last Series II was produced in 1991. After the closure of Crown Coach in 1991, the designs and tooling were acquired by Indiana-based Carpenter Body Works in the hopes of adopting the Series II as part of the Carpenter model line. As Carpenter could not produce the model at a competitive price, the project was abandoned; however, several elements of the Series II styling (and its left-hand control panel) lived on in the final product, the 1992-1993 Carpenter/Spartan Coach RE.

Powertrain

References

External links

Wikimedia Commons has media related to Crown Supercoach buses.