K-class blimp

https://en.wikipedia.org/wiki/K-class_blimp

The K-class blimp was a class of blimps (non-rigid airship) built by the
Goodyear Aircraft Company of Akron, Ohio for the United States Navy. These
blimps were powered by two Pratt & Whitney Wasp nine-cylinder radial air-cooled
engines, each mounted on twin-strut outriggers, one per side of the control car
that hung under the envelope. Before and during World War II, 134 K-class blimps
were built, configured for patrol and anti-submarine warfare operations and were
extensively used in the Navy’s anti-submarine efforts in the Atlantic and
Pacific Ocean areas.

The K-class blimp was a product of the austere times of the American depression.
In 1937, K-2 was ordered from Goodyear as part of a contract that also bought
the L-1. The L-class was Goodyear’s standard advertising and passenger blimp.
K-2 was the production prototype for future K-class airship purchases. K-2 flew
for the first time at Akron, Ohio on December 6, 1938 and was delivered to the
Navy at NAS Lakehurst, New Jersey on December 16. The envelope capacity of the
K-2—404,000 ft³ (11,440 m³)—was the largest for any USN blimp up to that time.
K-2 was flown extensively as a prototype, and continued to operate testing new
equipment, techniques, and performing whatever tasks were needed, including
combat patrols in World War II.

On October 24, 1940, the Navy awarded a contract to Goodyear for six airships
(K-3 through K-8) that were assigned the designation Goodyear ZNP-K. These
blimps were designed for patrol and escort duties and were delivered to the Navy
in late 1941 and early 1942. K-3 through K-8 had only minor modifications to
K-2's design, the only major change was in engines from Pratt & Whitney
R-1340-16s to Wright R-975-28s. The Wright engine/propeller combination proved
excessively noisy and was replaced in later K-ships with slightly modified Pratt
& Whitney engines. The K-3 cost $325,000. A series of orders for more K-class
blimps followed. Twenty-one additional blimps (K-9 through K-30) were ordered on
14 October 1942. On 9 January 1943, 21 more blimps (K-31 through K-50) were
ordered. The envelope size of K-9 through K-13 was increased to 416,000 ft³
(11,780 m³) and those delivered thereafter used an envelope of 425,000 ft³
(12,035 m³). The final contract for the K-class blimp were awarded in mid-1943
for 89 airships. Four blimps from this order were later canceled. The remaining
deliveries were assigned numbers K-51 through K-136. But, the number K-136 was
not assigned to a specific airship as the control car assigned for K-136 was
used to replace the car for K-113. The original car for K-113 was destroyed in a
fire.


Role
Patrol airship

Manufacturer
Goodyear-Zeppelin and Goodyear Aircraft Corporation

First flight
6 December 1938

Retired
1959

Primary user
United States Navy

Number built
134

The K-ships were used for anti-submarine warfare (ASW) duties in the Atlantic
and Pacific Oceans as well as the Mediterranean Sea. All equipment was carried
in a forty foot long control car. The installed communications and
instrumentation equipment allowed night flying. The blimps were equipped with
the ASG-type radar, that had a detection range of 90 mi (140 km), sonobuoys, and
magnetic anomaly detection (MAD) equipment. The K-ships carried four Mk-47 depth
bombs, two in a bomb bay and two externally, and were equipped with a .50 in
(12.7 mm) Browning machine gun in the forward part of the control car. An
aircrew of 10 normally operated the K-ships, consisting of a command pilot, two
co-pilots, a navigator/pilot, airship rigger, an ordnanceman, two mechanics, and
two radiomen.

On 1 June 1944, two K-class blimps of United States Navy (USN) Airship Patrol
Squadron 14 (ZP-14) completed the first transatlantic crossing by non-rigid
airships. K-123 and K-130 left South Weymouth, MA on 28 May 1944 and flew
approximately 16 hours to Naval Station Argentia, Newfoundland. From Argentia,
the blimps flew approximately 22 hours to Lajes Field on Terceira Island in the
Azores. The final leg of the first transatlantic crossing was about a 20-hour
flight from the Azores to Craw Field in Port Lyautey (Kenitra), French Morocco.
The first pair of K-ships were followed by K-109 & K-134 and K-112 & K-101 which
left South Weymouth on 11 and 27 June 1944, respectively. These six blimps
initially conducted nighttime anti-submarine warfare operations to complement
the daytime missions flown by FAW-15 aircraft (PBYs and B-24s) using magnetic
anomaly detection to locate U-boats in the relatively shallow waters around the
Straits of Gibraltar. Later, ZP-14 K-ships conducted minespotting and
minesweeping operations in key Mediterranean ports and various escort missions
including that of the convoy carrying Franklin Roosevelt and Winston Churchill
to the Yalta Conference in early 1945. In late April 1945, K-89 and K-114 left
Weeksville NAS in North Carolina and flew a southern transatlantic route to NAS
Bermuda, the Azores, and Port Lyautey where they arrived on 1 May 1945 as
replacements for Blimp Squadron ZP-14.

The ability of the K-ships to hover and operate at low altitudes and slow speeds
resulted in detection of numerous enemy submarines as well as assisting in
search and rescue missions. The K-ships had an endurance capability of over 24
hours which was an important factor in the employment of ASW tactics.

The mooring system for the K-ship was a 42 ft (12.8 m) high triangular mooring
mast that was capable of being towed by a tractor. For advance bases where
moving the mooring mast was not needed, a conventional stick mast was used. A
large ground crew was needed to land the blimps and moor them to the mast.

During the war, one K-ship—K-74—was lost to enemy action when it was shot down
by U-134 in the Straits of Florida on 18 July 1943. The crew was picked up eight
hours later, except for one man who was attacked by a shark and drowned just
before being rescued.

Specifications (K-14)

General characteristics
Crew: 9-10
Length: 251 ft 8 in (76.73 m)
Diameter: 57 ft 10 in (17.63 m)
Volume: 425,000 ft3 (12,043 m3)
Useful lift: 7,770 lb (3,524 kg)
Powerplant: 2 × Pratt & Whitney R-1340-AN-2 radials, 425 hp (317 kW) each each

Performance
Maximum speed: 78 mph (125 km/h)
Cruise speed: 58 mph (93 km/h)
Range: 2,205 miles (3,537 km)
Endurance: 38 hours 12 min

Armament
1 × .50 in (12.7 mm) M2 Browning machine gun
4 × 350 lb (160 kg) Mark 47 depth charges




*