Northrop BT: American Dive Bomber

Northrop BT-1, aircraft number 18 of Bombing Five off USS Yorktown pictured in flight on 9 April 1938.

The Northrop BT was an American two-seat, single-engine monoplane dive bomber built by the Northrop Corporation for the United States Navy. At the time, Northrop was a subsidiary of the Douglas Aircraft Company. While unsuccessful in its own right, the BT was subsequently redesigned into the Douglas SBD Dauntless, which would form the backbone of the Navy's dive bomber force.

The design of the initial version began in 1935. It was powered by a 700 hp (520 kW; 710 PS) Pratt and Whitney XR-1535-66 double row air-cooled radial engine and had hydraulically actuated perforated split flaps (dive brakes), and main landing gear that retracted backwards into fairing "trousers" beneath the wings. The perforated flaps were invented to eliminate tail buffeting during diving maneuvers.

The next iteration of the BT, the XBT-1, was equipped with a 750 hp (560 kW; 760 PS) R-1535. This aircraft was followed in 1936 by the BT-1, powered by an 825 hp (615 kW; 836 PS) R-1535-94 engine. One BT-1 was modified with a fixed tricycle landing gear and was the first such aircraft to land on an aircraft carrier.

The final variant, the XBT-2, was a BT-1 modified to incorporate landing gear which folded laterally into recessed wheel wells, leading edge slots, a redesigned canopy, and was powered by an 800 hp (600 kW; 810 PS) Wright XR-1820-32 radial. The XBT-2 first flew on 25 April 1938, and after successful testing the Navy placed an order for 144 aircraft. In 1939 the aircraft designation was changed to the Douglas SBD-1 with the last 87 on order completed as SBD-2s. By this point, Northrop had become the El Segundo division of Douglas aircraft, hence the change.

The U.S. Navy placed an order for 54 BT-1s in 1936 with the aircraft entering service during 1938. BT-1s served on USS Yorktown and Enterprise. The type was not a success in service due to poor handling characteristics, especially at low speeds, "a fatal flaw in a carrier based aircraft." It was also prone to unexpected rolls and a number of aircraft were lost in crashes.

Northrop BT-1s appeared in pre-war yellow wing paint schemes in the Technicolor film Dive Bomber (1941) starring Errol Flynn.

Variants

XBT-1: Prototype, one built.

BT-1: Production variant, 54 built.

Role: Dive bomber

National origin: United States

Manufacturer: Northrop Corporation

First flight: 19 August 1935

Primary user: United States Navy

Number built: 55

Developed into: Douglas SBD Dauntless

Crew: two (pilot and gunner)

Length: 31 ft 8 in (9.65 m)

Wingspan: 41 ft 6 in (12.65 m)

Height: 9 ft 11 in (3.02 m)

Wing area: 319 sq ft (29.6 m2)

Empty weight: 4,606 lb (2,094 kg)

Maximum takeoff weight: 7,197 lb (3,271 kg)

Powerplant: 1 × Pratt & Whitney R-1535-94 Twin Wasp Jr. double row radial air-cooled engine, 825 hp (615 kW)

Maximum speed: 193 kn (222 mph, 357 km/h) at 9,500 ft (2,900 m)

Cruise speed: 167 kn (192 mph, 309 km/h)

Range: 1,000 nmi (1,150 mi, 1,852 km)

Service ceiling: 25,300 ft (7,710 m)

Rate of climb: 1,270 ft/min (6.5 m/s)

Guns: 1 × .50 in (12.7 mm) machine gun; 1 × .30 in (7.62 mm) machine gun

Bombs: 1,000 lb (454 kg) bomb under fuselage

BT-1S: A BT-1 (c/n346, BuNo 0643) was fitted with a fixed tri-cycle undercarriage. This aircraft was damaged in a crash on 6 February 1939, returned to Douglas and repaired to BT-1 standard.

XBT-2: One BT-1 modified with fully retractable landing gear and other modifications.

BT-2: Production variant of the XBT-2, 144 on order completed as SBD-1 and SBD-2.

Douglas DB-19: One BT-1 (c/n346, BuNo 0643), the former BT-1S, was modified as the DB-19 which was tested by the Imperial Japanese Navy as the Douglas DXD1 (long designation - Douglas Navy Experimental Type D Attack Aircraft)

Operators

United States

United States Navy

Bibliography

Bowers, Peter M. United States Navy Aircraft since 1911. Annapolis, MD: Naval Institute Press, 1990.

Brazelton, David. The Douglas SBD Dauntless, Aircraft in Profile 196. Leatherhead, Surrey, UK: Profile Publications Ltd., 1967.

Drendel, Lou. U.S. Navy Carrier Bombers of World War II. Carrollton, TX: Squadron/Signal Publications, Inc., 1987.

Gunston, Bill. The Illustrated History of McDonnell Douglas Aircraft: From Cloudster to Boeing. London: Osprey Publishing, 1999.

Kinzey, Bert. SBD Dauntless in Detail & Scale, D&S Vol.48. Carrollton, TX: Squadron/Signal Publications, Inc., 1996.

Listemann, Phil. Northrop BT-1 (Allied Wings No.3). France: www.raf-in-combat.com, 2008.

Swanborough, Gordon and Peter M. Bowers. United States Navy Aircraft since 1911. London: Putnam, Second edition, 1976.

Northrop BT-1, aircraft number 2 of Bombing Five off USS Yorktown, Oakland, March 1940.

 

Northrop BT-1 of Bombing Five off the USS Yorktown.

Northrop BT-1 of dive bomber squadron VB-5, assigned to the U.S. aircraft carrier USS Yorktown (CV-5). Deliveries to VB-5 began in April 1938.

Aircraft number 10 of Bombing Squadron Five (VB-5) assigned to the Yorktown Air Group in the aircraft carrier USS Yorktown (CV-5). Struck off charge October 31, 1944.

U.S. Navy Northrop BT-1 (BuNo 0815) of dive bombing squadron VB-6, circa 1939/40.

U.S. Navy Northrop BT-1 pictured sitting on flight line outside of a hangar at El Segundo, California.

Eleven U.S. Navy Northrop BT-1s of Bombing Squadron Five (VB-5) pictured sitting lined up. In the background are three Vought SBUs and a USAAC North American O-47. Note the sign at the right: "Notice! Photographing Military Airplanes is Forbidden by U.S. Government!"

Northrop BT-1 modified to test tricycle landing gear, circa 1936-37.

U.S. Navy Northrop BT-1 dive bombers flying over Miami , Florida, October 1939.

Northrop BT-1, landing at Oakland, California.

U.S. Navy Northrop BT-1 (BuNo 0614) of Bombing Squadron 5 (VB-5) goes into the starboard catwalk during a landing accident aboard the aircraft carrier USS Yorktown (CV-5), circa 1940. Note man in asbestos suit and other members of the flight deck crew running to assist.

A U.S. Navy Northrop BT-1 (BuNo 0631) of Bombing Squadron 6 (VB-6) aboard the aircraft carrier USS Enterprise (CV-6), circa 1940. The yellow color of its wings visible and 'true blue' color of vertical and horizontal stabilizers were assigned to the Enterprise Air Group. The BT-1s were removed from fleet service by 20 April 1941. The BT-1 0631 then served as a training plane and was finally retired on 31 October 1944.

U.S. Navy Northrop BT-1 of bombing squadron VB-6 in flight. VB-6 was assigned to the aircraft carrier USS Enterprise (CV-6).

Northrop BT-1 of VJ-3.

Northrop XBT-1 (BuNo 9745) on 4 December 1936.

XBT-2 (BuNo 0627) prototype on 23 July 1938. This was to be the prototype of the later Douglas SBD Dauntless, although canopy and tail would differ from the XBT-2.

Northrop (Douglas) XBT-2 undergoing handling and drag reduction tests in the Langley 30 x 60 Full Scale Tunnel. This is the revision of the Northrop BT-1 that eventually became the Douglas SBD prototype. At the time this aircraft was produced, Northrop became the El Segundo Division of Douglas.

U.S. Navy Northrop XBT-1 prototype (BuNo 9745) which made its first flight in August 1935.

View taken on the flight deck of the aircraft carrier USS Enterprise (CV-6) showing U.S. Secretary of the Navy Frank Knox inspecting aircraft (Northrop BT-1s). Knox is followed by Admiral James O. Richardson, USN (center). Commander Milton L. Deyo, USN (Aide to SecNav), also is visible, at far right.

Northrop BT-1, aircraft 13 of Bombing Five off USS Yorktown.

Douglas XBT-2, El Segundo, circa 1939.

Naval Aircraft Factory N3N: American Primary Trainer

 

A U.S. Marine Corps Naval Aircraft Factory N3N-3 Canary (BuNo 1777) at Parris Island, South Carolina, in May 1942. The N3Ns were used to tow Schweizer LNS-1 gliders of the Marine glider program.

The Naval Aircraft Factory N3N was an American tandem-seat, open cockpit, primary training biplane aircraft built by the Naval Aircraft Factory (NAF) in Philadelphia, Pennsylvania, during the 1930s.

Built to replace the Consolidated NY-2 and NY-3, the N3N was successfully tested as both a conventional airplane and a seaplane. The seaplane used a single float under the fuselage and floats under the outer tips of the lower wing. The conventional airplane used a fixed landing gear. The prototype XN3N-1 was powered by a radial Wright designed Wright J-5 engine. An order for 179 production aircraft was received. Near the end of the first production run the engine was replaced with the Wright R-760-2 Whirlwind radial. The aircraft is completely metal using bolts and rivets rather than the more common welded steel tubing fuselages. Early production models used aluminum stringers formed for cancelled airship construction orders.

The NAF delivered 997 N3N aircraft beginning in 1935. They included 180 N3N-1s and 816 N3N-3s. Four N3N-3s were delivered to the United States Coast Guard in 1941. Production ended in January 1942 but the type remained in use through the rest of World War II. The N3N was the last biplane in US military service - the last (used by the U.S. Naval Academy for aviation familiarization) were retired in 1961. The N3N was also unique in that it was an aircraft designed and manufactured by an aviation firm wholly owned and operated by the U.S. government (the Navy, in this case) as opposed to private industry. For this purpose, the U.S. Navy bought the rights and the tooling for the Wright R-760 series engine and produced their own engines. These Navy built engines were installed on Navy built airframes.

Postwar, many surviving aircraft were sold on the US civil aircraft market and bought for operation by agricultural aerial spraying firms and private pilot owners. A number are still (2014) active in the USA.

Variants

XN3N-1: First prototype aircraft, Bureau of Aeronautics number 9991.

N3N-1: Two-seat primary trainer biplane, powered by a 220-hp (164-kW) Wright J-5 radial piston engine. 179 were built.

XN3N-2: One prototype only (Bureau number 0265) powered by a 240-hp (179-kW) Wright R-760-96 radial piston engine.

XN3N-3: One production N3N-1 (0020) was converted into a 'dash three' prototype.

N3N-3: Two-seat primary trainer biplane, powered by a 235-hp (175-kW) Wright R-760-2 Whirlwind 7 radial piston engine. 816 built.

Role: Training aircraft

National origin: United States

Manufacturer: Naval Aircraft Factory

First flight: August 1935

Introduction: 1936

Retired: 1961

Operators:

United States

United States Coast Guard

U.S. Marines

United States Navy

Paraguay

Paraguayan Naval Aviation

Two N3N-3s received by Lend-Lease Program.

Number built: 997

Crew: 2

Length: 25 ft 6 in (7.77 m)

Wingspan: 34 ft 0 in (10.36 m)

Height: 10 ft 10 in (3.3 m)

Wing area: 305 ft² (28.3 m²)

Empty weight: 2,090 lb (948 kg)

Gross weight: 2,792 lb (1,266 kg)

Powerplant: 1 × Wright R-760-2 Whirlwind radial, 235 hp (175 kW)

Maximum speed: 126 mph (203 km/h)

Range: 470 miles (756 km)

Service ceiling: 15,200 ft (4,635 m)

Rate of climb: 900 ft/min ( m/s)

Communications were done by the instructor through a speaking tube to the aft-seated student. Communications back were agreed-upon gestures.

Aircraft on Display

National Air and Space Museum, Udvar Hazy Center, Chantilly Virginia

National Museum of Naval Aviation, Pensacola Florida

Kalamazoo Aviation History Museum, Kalamazoo Michigan

USS Lexington Museum, Corpus Christi Texas

Western Antique Aeroplane & Automobile Museum, Hood River, Oregon

Warhawk Air Museum, Nampa, Idaho

This U.S. Navy Naval Aircraft Factory N3N-3 Canary was the first aircraft landing at the Naval Air Station Jacksonville, Florida, on 7 September 1940.

U.S. Navy N3N trainers awaiting engines and other parts at Naval Aircraft Factory, Philadelphia, Pennsylvania, 28 June 1937.

Production of U.S. Navy N3N Canary trainers at the Naval Aircraft Factory, Philadelphia; c. 1930s.

View of the assembly line of the N3N Yellow Peril at the U.S. Navy's Naval Aircraft Factory; c. 1937. The N3N made its first flight in August 1935.

Three U.S. Navy N3N trainers flying over Naval Air Station Glenview, Illinois, in the early 1940s.

N3N-1, BuNo 0984.

N3N-1s on training flight.

N3N-3, BuNo 1790, with N3N-1 landing gear.

Naval Aircraft Factory N3N-3 Canary trainer (1787).

Naval Aircraft Factory N3N-1.

NAF XN3N-1 (9991) on wheels.

Starting the engine of an N3N-1.

Tail of N3N-3, BuNo 2590, at left, with another N3N-3 in background.

N3N-3s on the flight line.

A USMC pilot stands beside his N3N-3. Parris Island, South Carolina, c. May 1942. The N3N-3 was used to tow gliders.

A USMC pilot checks the Wright Whirlwind radial piston engine of his N3N-3 Canary, Parris Island, South Carolina, c. May 1942.

A USMC pilot stands beside his N3N-3. Parris Island, South Carolina, c. May 1942.

A USMC pilot with an N3N-3. Parris Island, South Carolina, c. May 1942.

A USMC pilot with an N3N-3. Parris Island, South Carolina, c. May 1942.

A USMC N3N-3 Canary over Parris Island, South Carolina, c. May 1942.

A U.S. Marine Corps NAF N3N-3 “Yellow Peril” towing three LNS-1 gliders at Parris Island, South Carolina; May 1942.

A U.S. Marine Corps NAF N3N-3 “Yellow Peril” towing three LNS-1 gliders at Parris Island, South Carolina. May 1942.

A U.S. Marine Corps NAF N3N-3 “Yellow Peril” towing three LNS-1 gliders at Parris Island, South Carolina. May 1942.

Marine pilot trainees with NAF N3N-3 at Parris Island, South Carolina; May 1942.

Marine pilot in NAF N3N-3 at Parris Island, South Carolina; May 1942.

A U.S. Navy Naval Aircraft Factory N3N-1 (BuNo 0680) assigned to flight test duties at Naval Air Station Anacostia, Washington D.C.

The single U.S. Navy Naval Aircraft Factory XN3N-2 Canary or Yellow Peril (BuNo 0265) training biplane in flight. Various handling and control problems of the N3N-1 were tried to correct with the XN3N-2 prototype which was ordered  in October 1935. This aircraft was powered by the 240 hp (179 kW) Wright R-760-96 engine. In order to reduce the tail heaviness, the aircraft was equipped with new engine mounts and a longer engine cowling, some equipment was also moved forward. The XN3N-2 made its first flight at the NAF Mustin Field in Philadelphia, Pennsylvania, on 11 August 1936. However, it was found that this aircraft did not adequately improve performance. Therefore, the N3N-1 BuNo 0020 was converted into the XN3N-3 prototype, which went into production.

Aviation cadets check flight boards for last minute instructions at Naval Air Training Center Corpus Christi, Texas. In the background is a NAF N3N-3 (2828).

A U.S. Coast Guard Naval Aircraft Factory N3N-3 Canary trainer (V196) in 1941. Four were acquired by the U.S. Coast Guard in December 1940 to expedite pilot training. The N3N was a two-place primary training biplane built by the Naval Aircraft Factory (N.A.F.) in Philadelphia, Pennsylvania. The N3N was delivered both as a landplane and a seaplane. Four of the N3N-3 aircraft were delivered to the U.S. Coast Guard in 1941.

A U.S. Navy Naval Aircraft Factory N3N-3 Yellow Peril (BuNo 2885) photographed in front of building 57, Naval Air Station Anacostia, Washington D.C. in 1940. A Grumman JRF-4 Goose (BuNo 3852), assigned to NAS Anacostia, is in the background. This aircraft was sold by the U.S. Navy on 31 July 1946. It later crashed on 3 December 1946 at the Llanganattes Range, Ecuador (civil registration HC-SBL).

U.S. Navy Stearman N2S and Naval Aircraft Factory N3N training planes taxiing to the flight line at Naval Air Station Corpus Christi, Texas, during flight training operations in 1942-1943. The plane in foreground is a Stearman N2S-3.

A U.S. Navy primary flight training planes at the Naval Air Station Corpus Christi, Texas, 1943. The aircraft are either Naval Aircraft Factory N3N Canarys (with red fuselage band), or Stearman N2S Kaydets. Note the tetrahedron wind direction indicator in the upper right.

U.S. Navy Naval Aircraft Factory N3N and Stearman N2S trainers on the flight line at Naval Air Station Corpus Christi, Texas, 1941-1942.

Dozens of so-called Yellow Perils—Naval Aircraft Factory N3N-3 primary trainers—fill the ramps, taxiways, and sky at Rodd Field, one of Naval Air Station Corpus Christi's auxiliary fields, in a 1942 watercolor by Vernon Howe Bailey.

NAF N3N-1; Oakland.

Naval Aircraft Factory XN3N-1 (9991).

NAF XN3N-1 (9991) with greenhouse cockpit; Anacostia, 1944.

A U.S. Navy Naval Aircraft Factory N3N-1 Canary (BuNo 0717) in flight; c. 1930s.

NAF N3N-1 0692; Oakland, 1940.

NAF N3N-3s over County Causeway, Palm and Star Islands, Miami Beach, Florida.

A U.S. Coast Guard Naval Aircraft Factory N3N-3 at Floyd Bennett Field, New York, in 1943. The USCG operated four N3Ns from 1940 to 1945 (V193-V196).

NAF N3N front cockpit.

NAF N3N rear cockpit.

NAF XN3N-1 (9991) on floats.

NAF N3N-1s (0037 in foreground).

A U.S. Navy Naval Aircraft Factory N3N-1 Canary trainer (BuNo 0081) taking off on 7 March 1944.

Sailors standing in a hanger, between two aircraft, at Naval Air Station Corpus Christi. The aircraft on the left is a Vought OS2U-3 Kingfisher, while the aircraft on the right is a Naval Aircraft Factory N3N-3; September 1942.

Mary Josephine Farley, who at 20 is considered a top notch mechanic, working on a Wright Whirlwind airplane motor which she rebuilt at a Naval Air Base. The aircraft is an N3N-3 floatplane; c. October 1942.

A U.S. Navy Naval Aircraft Factory N3N-1 trainer at the Naval Air Station Corpus Christi, Texas; August 1942.

A U.S. Navy Naval Aircraft Factory N3N-1 (BuNo 0041) training biplane with floats on the beach at Naval Air Station Pensacola, Florida. An instructor demonstrates handling to a student.

A U.S. Navy Naval Aircraft Factory N3N-3 trainer (BuNo 2920) assigned to VN-7D8 (Training Squadron 7, Eighth Naval District) is craned out of the water at Naval Air Station Pensacola, Florida; c. 1944.

A U.S. Navy Naval Aircraft Factory N3N-3 Canary (BuNo 2736) on floats, used for primary seaplane training. The aircraft paint color was all-yellow with silver floats and this picture was taken on 7 January 1942 at the Naval Air Station Jacksonville, Florida.

A U.S. Navy Naval Aircraft Factory N3N-3 trainer in flight near Naval Air Station Anacostia, Washington D.C.

Flight's over—an N3N training plane is safe on the dolly and pilot and instructor go back to the hangar. After fulfilling their service schedules, planes at the Corpus Christi, Texas, naval air base are completely reconditioned by civil service mechanics attached to the base. U.S. Navy Naval Aircraft Factory N3N-3 trainers at the Naval Air Station Corpus Christi, Texas; August 1942.

A U.S. Navy Naval Aircraft Factory N3N-3 trainer (BuNo 1759) in flight over the Pennsylvania countryside.

A U.S. Navy Naval Aircraft Factory N3N-1 Canary trainer on a seaplane ramp at Naval Air Station Pensacola, Florida; c. 1942. The plane has panels removed for maintenance just aft of the engine. This N3N is BuNo 0265. This airplane is the only N3N-2 that was ever built. It was made to help correct some flight characteristics by raising the location of the horizontal elevator in relation to the lower wing. This is 0265 with a -1 rudder fitted as the -2 rudder was a different design all together. You can see the differences in tail design by looking at any picture of the -1 version.

An early U.S. Navy Consolidated PBY Catalina taxiing at low speed. Note the crewman on wing between the engines. There is a Naval Aircraft Factory N3N Yellow Peril in flight in front of and overhead; c. 1940.

N3N-1, BuNo 1978.

N3N-1.

A U.S. Marine Corps Naval Aircraft Factory N3N-3 Canary towing three Schweizer LNS-1 gliders of the Marine glider program at Parris Island, South Carolina. May 1942.

U.S. Marine Corps Schweizer LNS-1 gliders being towed by N3N-3 Canary over Parris Island, South Carolina. May 1942.

N3N-3.