Curtiss XBTC (Model 96) History

By 1942, the world was at war with the United States committed to the fight in Africa, Europe, and the Pacific. The Pacific Theater required a major investment in over-water and on-water solutions and, for the attack role, the torpedo bomber and dive bomber were king. In the decade prior, the United States Navy (USN) shifted policy and accepted designs covering torpedo and bombing roles individually. However, during the war, it was seen that a combination design able to fulfill both roles was more tactically sound against the Empire of Japan's vaunted naval fleet.

In February 9th, 1942, the USN sought a new combination design and contracted with Curtiss Aeroplace and Motor Company to fulfill the requirement. The engine of choice became the Wright R-3350 air-cooled radial driving a three-bladed propeller unit at the nose and the usual crew of two or three was reduced to just one as technical advances and wartime theory offered simplification. To cover the bombing role, an internal bomb bay was required while a single torpedo (Mk 13-2 family) could be held externally along the ventral fuselage line. Two external hardpoints were also available for drop bombs. The structure of the new aircraft would have to satisfy the rigors and stresses inherent in the dive bombing action. Standard, fixed armament centered on 4 x 20mm automatic cannons for ground strafing and an possible air-to-air action the operator might encounter. For enhanced survivability, self-sealing fuel tanks were a must.

The performance specifications included an optimal operating range of 1,000 miles fully-laden. Range could increase to 1,500 miles with the optional fuel drop tanks.

Curtiss engineers moved on a pair of designs, the first fitting a conventional arrangement involving the R-3350 radial of 2,300 horsepower mated to a single three-bladed propeller unit at the nose and another housing the experimental Pratt & Whitney (PW) XR-4360-14 "Wasp Major" super-charged, water-injected radial of 3,000 horsepower driving a pair of three-bladed propellers in a contra-rotating arrangement. The result was the project "Model 96" for the company.

USN authorities liked what they saw in the promising attacker and contracted for both to be completed, each with their respective engine installations, to be known under experimental designations "XBTC-1" (Wright engine) and "XBTC-2" (Pratt & Whitney engine). The latter differed not only in engine and prop install but also in dimensions, being larger than its sister, and incorporated a Fowler flap (Model A wing) or duplex flap (Model B wing) arrangement in the wings. Dive brakes and edge slats also were standard.

Of note is that this Curtiss / USN marriage marked the first large scale commitment by the service in attempting to satisfy a multi-role attack platform when such ventures were typically reserved for fighter types.

The company initially moved fast on the agreement and delivered mockups before the end of 1942. Not all was right, however, for the Curtiss was deep in the American war effort and - coupled to the Army need for the Pratt & Whitney radial - the program began to stall into 1943 by which point the XBTC-1 initiative was dead before the end of the year by the Navy's decision. The service did, indeed, move forward with the XBTC-2 and contracted for two prototypes.

Curtiss XBTC (Model 96) Specification

BASICS

Service Year

1945

Origin

United States

Status

CANCELLED

Development Ended.

Crew

1

Production

2

MANUFACTURER(S)

Curtiss Aeroplane and Motor Company - USA

OPERATORS

United States (cancelled)

ROLES

Ground Attack (Bombing, Strafing)

Ability to conduct aerial bombing of ground targets by way of (but not limited to) guns, bombs, missiles, rockets, and the like.

Special-Mission: Anti-Submarine Warfare (ASW)

Equipped to search, track, and engage enemy underwater elements by way of specialized onboard equipment and weapons.

Special-Mission: Anti-Ship

Equipped to search, track, and engage enemy surface elements through visual acquisition, radar support, and onboard weaponry.

Maritime / Navy

Land-based or shipborne capability for operating over-water in various maritime-related roles while supported by allied naval surface elements.

X-Plane (Developmental, Prototype, Technology Demonstrator)

Aircraft developed for the role of prototyping, technology demonstration, or research / data collection.

NOTABLE QUALITIES

FOLDING WING(S)

Mainplanes are designed to fold, improving storage on land and at sea.

RUGGED AIRFRAME

Inherent ability of airframe to take considerable damage.

INTERNAL BAY

Fuselage volume includes space for internally-held weapons or special-mission equipment.

EXTENDED RANGE PERFORMANCE

Capability to travel considerable distances through onboard fuel stores.

MARITIME OPERATION

Ability to operate over ocean in addition to surviving the special rigors of the maritime environment.

BAILOUT PROCESS

Manual process of allowing its pilot and / or crew to exit in the event of an airborne emergency.

ENCLOSED CREWSPACE(S)

Features partially- or wholly-enclosed crew workspaces.

RETRACTABLE UNDERCARRIAGE

Features retracting / retractable undercarriage to preserve aerodynamic efficiency.

TORPEDO ARMAMENT

Ability to launch / release torpedoes against ocean-going threats / targets.

DIMENSIONS & WEIGHTS

Length

39. 0 ft

(11. 90 m)

Width/Span

50. 0 ft

(15. 25 m)

Height

13. 0 ft

(3. 95 m)

Empty Wgt

13,415 lb

(6,085 kg)

MTOW

21,660 lb

(9,825 kg)

Wgt Diff

+8,245 lb

(+3,740 kg)

MAINPLANE STRUCTURE

monoplane / low-mounted / straight

Monoplane

Design utilizes a single primary wing mainplane; this represent the most popular mainplane arrangement.

Low-Mounted

Mainplanes are low-mounted along the sides of the fuselage.

Straight

The planform involves use of basic, straight mainplane members.

(Structural descriptors pertain to the Curtiss XBTC-2 production variant)

POWER & PERFORMANCE

Installed:

1 x Pratt & Whitney R-4360 Wasp Major air-cooled radial piston engine developing 3,000 horsepower driving 2 c Three-bladed propeller units at the nose in contra-rotating arrangement.

Max Speed

376 mph

(605 kph | 327 kts)

Cruise Speed

190 mph

(305 kph | 165 kts)

Max. Speed Diff

+186 mph

(+300 kph | 162 kts)

Ceiling

26,247 ft

(8,000 m | 5 mi)

Range

1,836 mi

(2,955 km | 5,473 nm)

Rate-of-Climb

2,250 ft/min

(686 m/min)

MACH Regime (Sonic)

Sub

Trans

Super

Hyper

HiHyper

ReEntry

RANGES (MPH) Subsonic: <614mph | Transonic: 614-921 | Supersonic: 921-3836 | Hypersonic: 3836-7673 | Hi-Hypersonic: 7673-19180 | Reentry: >19030

ARMAMENT

PROPOSED:4 x 20mm automatic cannons in the wings (inboard of wing-fold hinge). Up to 2,000lb of conventional drop bombs (2 x 1,000lb bombs) in the internal bomb bay or a single torpedo held under the fuselage. Also optional provision for external bomb mountings and jettisonable fuel tanks.

Supported Types

(Not all ordnance types may be represented in the showcase above)

HARDPOINTS

Hardpoint Mountings: 2

Mounting Points

X

-

-

-

-

-

3

1

2

-

-

-

-

-

HARDPOINT(S) KEY:

X

15

13

11

9

7

5

3

1

2

4

6

8

10

12

14

COLOR KEY:

Fuselage Centerline

Fuselage Port/Wingroot

Fuselage Starboard/Wingroot

Wing/Underwing

Wingtip Mount(s)

Internal Bay(s)

Not Used

Note: Diagram above does not take into account inline hardpoints (mounting positions seated one-behind-the-other).

VARIANTS

XBTC - Base Project Designation. XBTC-1 - Proposed prototype carrying the Wright R-3350 Duplex-Cyclone engine; not ordered. XBTC-2 - Prototype model fitting the Pratt & Whitney R-4360 Wasp Major air-cooled radial engine; two examples completed with Model A and Model B wing structures, respectively; First prototype scrapped, second prototype lost to accident.

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