Little known JB (Jet Bomb) designs

Vahe Demirjian

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It's been known that the Americans used captured V-1s as the basis of the JB-2 Loon, and that Northrop built the JB-1 and JB-10 flying wing cruise missiles. However, does anyone have drawings or some other specs regarding the little known JB-5, JB-6, JB-7, and JB-9? Andreas Parsch considers it almost certain that the JB-9 was given the Wright Field Air Material Command designation MX-626.

Note: The JB-8 designation was a short-lived designation for the Boeing ASM-A-1 [GAPA], an early US surface-to-air missile.
 
Here's the reports on them from USAAF "Guided Missiles: development Status and Availability, Ass't Chief of Air Staff, Materiel and Services, Materiel Division from the 28 Jan 45 report at NARA II. JB.jpg
 
However, does anyone have drawings or some other specs regarding the little known JB-5, JB-6, JB-7, and JB-9? Andreas Parsch considers it almost certain that the JB-9 was given the Wright Field Air Material Command designation MX-626.

1F (1)​

JB-5, JET BOMB, AIR-TO-GROUND 500# BOMB MISSILE

1. Description - A configuration (designed by R. T. Jones of N.A.C.A.) of 850 lbs. total weight, which includes a 500# G.P. bomb. Length is 10 ft. or less and wing span approximately 5 ft. Speed boost propulsion will probably be 4 or 5 standard 4.5 inch rockets. A new type of highly sensitive accelerometer is being developed to use with this missile in order to secure a straight-line trajectory after launching. There will not be any remote control.

2. Characteristics - 250 miles per hour launching speed and striking velocity of approximately 500 m.p.h.

3. Comments - Proposals have been requested from several aircraft companies. No estimates are available as yet on schedule of first experimental models. Curtiss-Wright have submitted interesting proposal on a simplified control and plans are being considered for a three month study period. Flying models should be available in 3 to 5 months after completion of study period. Twenty-five items will probably be ordered.

C5-6380, AF
1F (1)
28 January 1945​
 
1C (3)​

JB-9 JET BOMB, SHORT RANGE, GROUND-TO-GROUND

1. Description - Design consists of three component parts: 250 lb. warhead, airfoil and control assembly, and jet motor (a 180 to 240 second rocket using Monsanto powder is now considered). The maximum weight of any component will not exceed 325 pounds, and the components can be bolted together without adjustment at the launching site. Overall size is 10’ long, 6’ wing span and 14" diameter. Intends to use same type of radar beacon type control (AN/APW-1 or similar) as the JB-2.

2. Launching - From 30 ft. truck-mounted ramp, with pre-fabricated assembly of six 4.5 inch standard rockets. Take-off speed approximately 180 m.p.h.

3. Characteristics - Range is 10 - 50 miles and will be dependent on propulsion unit. Maximum speed 300 - 340 m.p.h. Radar plotting accuracy estimated by A.T.S.C. is ±15 yards in range and ±0.5 mils or better in azimuth (±3/4 yards error per mile or range). Overall accuracy will be less because of errors in directing and errors in anticipating trajectory of final dive from the planned operating levels of 300 - 400 ft.

4. The device is planned for tactical use in close support of ground troop or amphibious operations, on fluid fronts in areas where the use of heavy artillery is desirable but is not feasible. Primary consideration is given to development of a missile which can be handled by enlisted personnel without recourse to heavy specialized auxiliary equipment for transportation, assembly and launching. A.T.S.C. estimates that each ramp crew should be able to assemble and launch six or more missiles per hour. Development of this missile is just starting on a 2A priority and consideration of a 1A priority has been requested. With a 1A priority, launching and pre-set flight tests should be possible within four to five months. Production contracts are being checked for 50, but no contracts have been placed.

C5-638O, AF
1C (3)
28 January 1945​
 
1C (2)​

JB-7 JET BOMB, LONG RANGE, GROUND-TO-GROUND

1. Description - Plans to use an airframe on which preliminary-designs have been completed by N.A.C.A. Overall length 25' 3", wing span 21’ 4”, body diameter 4’ 0”. Tail consists of two surfaces, 4½ ft. long at 35° angle to horizontal. Only one wing has aileron. Wing area is 100 sq. ft., gross weight 9700 lbs., explosive charge 4000 lbs., fuel weight 1750 lbs., required take-off speed 186 miles per hour. Now plans to use General Electric I-16 turbo-jet engine or similar. Remote or seeker type controls are not determined as yet.

2. Characteristics - Designed for maximum speed at sea level of 550 m.p.h. and range of 350 - 400 miles at maximum speed.

3. Availability and Comments - A contract will be placed for 25 experimental models by approximately 1 February 1945. Allocation of 25 I-16 engines has been requested with a delivery rate of 1 in April 1945 and 4 per month thereafter. The I-16 engine and its successor, the I-20, are well behind the Navy requirement schedule, and it is probable that any large production of these engines for jet bomb use would take at least a year after the placing of orders. The development priority of this missile is 1A.

C5-6380, AF
1C (2)
28 January 1945​
 
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