Gee Bee Model Z

https://en.wikipedia.org/wiki/Gee_Bee_Model_Z

The Granville Gee Bee Model Z was an American racing aircraft of the 1930s, the
first of the Super Sportster aircraft built by Granville Brothers Aircraft of
Springfield, Massachusetts, with the sole intent of winning the Thompson Trophy,
which it did in 1931. However, it soon suffered a fatal crash during a world
speed record attempt, starting the reputation of the Gee Bee aircraft as
killers.

Suffering from the effects of the Great Depression, the Granville Brothers
decided in July 1931 to build an aircraft to compete in that fall's Thompson
Trophy competition at the National Air Races in Cleveland, Ohio. They hoped that
a victory in the prestigious race would lead to additional orders for their line
of sporting aircraft.

Constructed in less than five weeks at a cost of under $5,000 USD, the Gee Bee
(for "Granville Brothers") Model Z, named City of Springfield, was a small,
tubby airplane. It was essentially the smallest possible airframe constructed
around the most powerful available engine, a supercharged Pratt & Whitney R-985
"Wasp Junior" radial engine, producing 535 horsepower (399 kW).


Role
Racing aircraft

National origin
United States of America

Manufacturer
Granville Brothers Aircraft

Designer
Bob Hall

First flight
August 22, 1931

Introduction
September 1931

Retired
December 5, 1931

Produced
1931

Number built
1

Unit cost

$5,000 USD


Developed into
Gee Bee Model R

First flying on August 22, 1931, the Gee Bee Z quickly proved to be tricky to
fly, but fulfilled every expectation with regards to its speed. Flown by pilot
Lowell Bayles, the Gee Bee Z attained the speed of 267.342 miles per hour
(430.245 km/h) at the National Air Races during the Shell Speed Dash qualifying
on September 1, then went on to win the Goodyear Trophy race, run over a course
of 50 miles (80 km), the next day at an average speed of 205 miles per hour (330
km/h). On the September 5, the aircraft's engineer, Bob Hall, flew the Gee Bee Z
to victory in the General Tire and Rubber Trophy race, then won again the next
day in a free-for-all event.

In the Thompson Trophy Race on September 7, Bayles was triumphant, winning with
an average speed of 236.24 miles per hour (380.19 km/h), winning over
competitors including Jimmy Doolittle, James "Jimmy" Wedell, Ben Howard, Dale
Jackson, Bill Ong, Ira Eaker, and Hall, who finished fourth in a Gee Bee Model
Y.

Following the Thompson Trophy race, the Gee Bee Z was re-engined with a larger,
750-horsepower (560 kW) Wasp Senior radial, in preparation for an attempt at
establishing a world speed record for landplanes at Wayne County Airport in
Detroit, Michigan. Unofficially clocked at 314 miles per hour (505 km/h) on a
trial run, it surpassed the previous record of 278 miles per hour (447 km/h) by
attaining 281.75 miles per hour (453.43 km/h) on December 1, 1931, but the
margin was too small for the record to be officially registered. A further
record attempt on December 5, 1931, would end in tragedy, the aircraft suffering
a wing failure and rolling into the ground, killing Bayles.

It was suspected that the Model Z's crash during a speed run in December 1931
was due to an unexpected failure of the gasoline tank cap, which may have come
loose and passed through the windshield. A bullet-proof windscreen and internal
fuel caps were part of the new design. Analysis of motion picture film of the
event examined frame-by-frame, is inconclusive. Control surface flutter is a
more likely cause. It is theorized that the gas cap struck the pilot and
incapacitated him, causing a sudden upset in pitch that led to uncontrolled
flutter in the right aileron which imparted undue stress on that wing, causing
it to pitch up sharply and fail. In addition, tests of a reproduction aircraft
have shown that the Gee Bee Z was susceptible to aerodynamic flutter at high
speed. The 1932 R-1 and its sister ship, the R-2, were the successors of the
previous year's Thompson Trophy-winning Model Z.

Legacy

Film of the crash of the Gee Bee Z has become some of the most well known
footage from the era of air racing. The crash also helped to establish the
reputation of Gee Bee racing aircraft as killers. The Super Sportster design
would be refined into the Gee Bee Model R for the 1932 air race season.

Two reproductions of the Gee Bee Z have been constructed. One, a faithful
reproduction of the original aircraft, was constructed by Jeff Eicher and Kevin
Kimball of Mount Dora, Florida, and is housed in the Fantasy of Flight museum in
Lakeland, Florida. The other, constructed by Bill Turner in 1978, features
extended wings and fuselage for better flight characteristics. It appeared in
1991 as both a static and flying prop in the Walt Disney feature film The
Rocketeer; it is now on display at the Museum of Flight in Tukwila, Washington.

Specifications (Gee Bee Model Z Super Sportster)

General characteristics
Crew: 1 (pilot)
Length: 15 ft 1 in (4.60 m)
Wingspan: 23 ft 6 in (7.16 m)
Height: 7 ft (2.1 m)
Wing area: 75 sq ft (7.0 m2)
Airfoil: M-6
Empty weight: 1,400 lb (635 kg)
Gross weight: 2,280 lb (1,034 kg)
Fuel capacity: 103 US gallons (390 l; 86 imp gal)
Powerplant: 1 × Pratt & Whitney R-985 "Wasp Jr." Radial, 535 hp (399 kW)
supercharged
Propellers: 2-bladed Curtiss Reed fixed pitch, 8 ft 2 in (2.49 m) diameter

Performance
Maximum speed: 232 kn; 430 km/h (267.342 mph)
Cruise speed: 200 kn; 370 km/h (230 mph)
Range: 782 nmi; 1,448 km (900 mi)




*