Mission

The main mission of the SB-29 was air search and rescue of personnel stranded in water, primarily to provide rescue support for units flying long distances over water. This objective was achieved using radar and a disposable A-3 lifeboat.

The SB-29s served in the Korean War, carrying A-3 lifeboats over the Yellow Sea and the Sea of Japan. During B-29 bombing missions, the SB-29s would maintain a position off the enemy coast and search for downed aircrews. Upon locating the stranded crews, the SB-29 would deploy an EDO A-3 rescue boat, with its descent slowed by parachutes.

Development

The success of the B-17H later referred to as the SB-17 Dumbo, prompted experimentation with a similar air-sea rescue aircraft based on the B-29 as early as 1944. The Superfortress’s extended range, increased lift capacity, and advanced features were all deemed improvements over the SB-17’s capabilities.

In 1949, a series of conversions for a select number of SB-29 aircraft commenced. According to recent research by Robert A. Mann, 25 such aircraft were primarily converted at Tinker Air Force Base.

Differences with B-29

The conversion from the Boeing B-29 to the SB-29 resulted in three distinct changes not found in the production B-29s:

• First, the AN/APQ-13 radome was relocated from between the bomb bays to the position typically occupied by the lower forward turret.
• Second, the 30-foot, droppable Edo A-3 lifeboat was mounted externally to the bomb bays.
• Lastly, the radio operator’s position was moved from the right-rear corner of the forward compartment to the rear pressurized compartment.

Despite these modifications, the remaining armament, which included the upper forward turret, two aft turrets, and tail guns, remained in the aircraft and operational.

Dimensions and Weights

DIMENSIONS	US	Metric
Wing
Span	141.2 ft	43 m
Incidence	4°	4°
Dihedral	4°29'23"	4°29'23"
Sweepback(LE)	7°1'26"	7°1'26"
Wing Area	1720 ft2	159.8 m2
Aspect Ratio	11.5	11.5
Wing Section	Boeing 117	Boeing 117
M.A.C.	154.41	47.1 m
Length	99 ft	30.2 m
Height	27.8 ft	8.5 m
Tread	28.5 ft	8.7 m
Prop. Grd Clearance	1.3 ft	0.4 m
WEIGHTS
Loading
Empty (E)	68,350 lbs	31.003 kg
Basic (E)	72,616 lbs	32.938 kg
Operating
Design	120,000 lbs	54.431 kg
Combat (*)	99,410 lbs	45.092 kg
Max Take Off (1)	120,662 lbs	54.731 kg
Max Landing (2)	120,662 lbs	54.731 kg

(E) Estimated
(*) For basic mission
(1) Limited by performance
(2) Limited by gear strength

Engines

Attribute	Value
POWER PLANT
No, & Model	(4) R-3350-57 or-83
Manufacturer	Curtiss - Wright Corp., Wright Aeronautical Corp. Division
Engine Spec	.787-C
Superch	1 stg, 1 spd
Turbo superch	B-11 or B-31
Turbo Manufacturer	General Electric Co.
Red, Gear Ratio	0.35
PROPELLER
Propeller Manufacturer	United Aircraft Corp., Hamilton Standard Propeller Division
Blade Design No.	6521A-6
Propeller Type	C.S., Full-Feathering, Hydromatic
No. Blades	4
Propeller Diameter	16' 7" (5 m)
ENGINE RATINGS
Take Off	2200/2800rpm
Military	2200/2600rpm/2500ft
Normal	2000/2400rpm/4000ft

Electronics

Equipment	US Designation
UHF Command	AN/ARC-27
VHF Command	AN/ARC-3
Liaison	AN/ARC-8
Interphone	AN/AIC-2A
Radio Compass	AN/ARN-7
Marker Beacon	RC-193A
Homing Adapter	AN/ARA-8
Glide Path	AN/ARN-5B
Radio Altimeter	SCR-718C
Radio Altimeter	AN/APN-1
Interrogator	SCR-729
IFF	SCR-695B
Loran	AN/APN-9
Search Radar	AN/APQ-13A
Pulse Doppler	AN/APA-52
Remote Control	AN/URW-3

Crew

The SB-29 had a normal crew of 11 that consisted of:

1. Pilot
2. Co-pilot
3. Flight engineer
4. Navigator
5. Bombardier
6. Remote control turret operator
7. Radar operator
8. (2) Radio operators
9. Left scanner
10. Right scanner

EDO A-3 lifeboat

The A-3 Airborne Lifeboat, or EDO Model 98, was created by the EDO Corporation in 1947 for the United States Air Force as a successor to the Higgins Industries A-1 lifeboat.

The lifeboat measured 30.05 feet in length, weighed 2,736 pounds when fully loaded, and could rescue up to 15 survivors. Powered by a Meteor 20 gasoline engine, it reached speeds of 8 knots and was dropped from the SB-29 using a 100-foot parachute.

The A-3 lifeboat featured various safety and functional components, such as a sail, a self-draining cockpit, and 20 watertight compartments. It was also equipped with bow and stern self-righting chambers that inflated automatically upon release, ensuring the boat was self-righting.

As it descended from 800 to 5,000 feet, the lifeboat’s 100-foot parachute helped stabilize its flight characteristics. The boat’s propellers and rudder were protected by metal guards, and the parachute was designed to reduce impact shock when the boat hit the water. The parachute also triggered valves to fill self-righting chambers with carbon dioxide and activated a white electric beacon for nighttime visibility.

Although not luxurious, the A-3 lifeboat was equipped with essential survival gear for aircrews in distress at sea. It featured ladders for easy boarding, a waterproof plexiglass shell to protect the engine, and storage for warm clothes, food, medical supplies, and other provisions for a crew of 15.

The lifeboat also included a gasoline-operated distiller to convert saltwater into fresh drinking water, as well as other essential equipment such as a sea anchor, fire extinguisher, compass, navigational aids, bilge pump, heaving quoit, tool kit, salt water soap, and a cockpit compartment heater.

Feature/Equipment	Description
US Designation	A-3 Airborne Lifeboat
Model	EDO Model 98
Manufacturer	EDO Corporation, College Point, Long Island, New York
Overall Length	30.05 feet
Weight (fully loaded)	2,736 pounds
Passenger Capacity	15 survivors
Material	Aluminum alloy
Engine	Four-cylinder, four-stroke Meteor 20 gasoline engine by Red Wing Motor Company
Propeller	Ailsa Craig propeller
Speed	8 knots under calm water conditions
Fuel Capacity	100 US gallons
Range	500 nm
Parachute	Single 100-foot diameter parachute, 7,857 square feet of nylon
Self-Righting	Equipped with bow and stern rubberized fabric self-righting chambers
Boarding Ladder	Included
Provisions	Food, water, and radio gear for rescued individuals
Protective Features	Metal guards for propellers and rudder; waterproof plexiglass shell for engine
Navigational Equipment	Compass, navigational aids
Survival Equipment	Warm clothes, medical supplies, sea anchor, fire extinguisher, bilge pump, heaving quoit, tool kit, salt water soap
Additional Features	Gasoline-operated distiller for fresh water; cockpit compartment heater; self-draining cockpit; 20 watertight compartments

Fuel system

Location	No. Tanks	Gals	Liters
Wing, outbond*	2	2640	9993
Wing, inbound*	2	2830	10713
Wing, center*	1	1333	5046
	Total	6803	25752

(*) Self Sealing tanks

Bombs

Bombs racks were installed but bombing capacities were not considered

Guns

During the conversion to SB-29 the upper forward turret, two aft turrets, and tail guns, remained in the aircraft. However, the B-29B Superfortress Standard Aircraft Characteristics of 1954 indicates that the Air Force removed all the guns.

Performance

The basic performance of the SB-29 was the following:

Loading and Performance

Conditions	Basic mission		Boat dropped		Ferry range
TAKE-OFF WEIGHT	120,662 lb	54.731 kg	120,662 lb	54.731 kg	120,662 lb	54.731 kg
Fuel at 6. 0 lb/gal (grade 100/130)	40,818 lb	18.515 kg	40,818 lb	18.515 kg	40,818 lb	18.515 kg
Payload (Boat)	3,491 lb(4)	1.583 kg	3,491 lb	1.583 kg	3,491 lb(4)	1.583 kg
Wing loading	70.2 lb/sq ft	342.7 kg/m2	70.2 lb/sq ft	342.7 kg/m2	70.2 lb/sq ft	342.7 kg/m2
Stall speed (power off)	95.7 kn	177 km/h	95.7 kn	177 km/h	95.7 kn	177 km/h
Take-off ground run at SL (1)	3,475 ft	1.059 m	3,475 ft	1.059 m	3,475 ft	1.059 m
Take-off to clear 50 ft (1)	5,075 ft	1.547 m	5,075 ft	1.547 m	5,075 ft	1.547 m
Rate of climb at SL (2)	730 fpm	223 m/min	730 fpm	223 m/min	730 fpm	223 m/min
Rate of climb at SL (one eng. out) (1)	435 fpm	133 m/min	435 fpm	133 m/min	435 fpm	133 m/min
Time: SL to 10, 000 ft (2)	15.0 min		15.0 min		15.0 min
Time: SL to 20,000 ft (2)	35.0 min		35.0 min		35.0 min
Service ceiling (100 fpm) (2)	32,800 ft	9.997 m	32,800 ft	9.997 m	32,800 ft	9.997 m
Service ceiling (one eng. out) (1)	21,600 ft	6.584 m	21,600 ft	6.584 m	21,600 ft	6.584 m
COMBAT RANGE					3,445 n.mi	6380 km
COMBAT RADIUS	1,685 n.mi	3.121 km	1,759 n.mi	3.258 km
Average cruise speed	172 kn	319 km/h	173 kn	320 km/h	173 kn	320 km/h
Initial cruising altitude	5,000 ft	1.524 m	5,000 ft	1.524 m	5,000 ft	1.524 m
Search altitude	Sea level		Sea level
Final cruising altitude	5,000 ft	1.524 m	5,000 ft	1.524 m	5,000 ft	1.524 m
Total mission time	19.8 hr		20.6 hr		20.0 hr
COMBAT WEIGHT	99,410 lb	45.092 kg	95,119 lb	43.145 kg	82,579 lb	37.457 kg
Combat altitude	Sea level		Sea level		5,000 ft	1.524 m
Combat speed (1)	239 kn	443 km/h	250 kn	463 km/h	254 kn	470 km/h
Combat climb (1)	1,345 fpm	410 m/min	1,520 fpm	463 m/min	1,780 fpm	543 m/min
Combat ceiling (500 fpm) (1)	35,600 ft	10.851 m	37,300 ft	11.369 m	39,500 ft	12.040 m
Service ceiling (100 fpm) (2)	38,600 ft	11.765 m	39,700 ft	12.101 m	42,600 ft	12.984 m
Service ceiling (one eng. out) (2)	32,400 ft	9.876 m	36,800 ft	11.217 m	38,800 ft	11.826 m
Max rate of climb at SL (1)	1,345 fpm	410 m/min	1,520 fpm	463 m/min	1,850 fpm	564 m/min
Max speed at optimum altitude (1)	334 kn/33,300 ft	619 km/h /10.150 m	349 kn/33,300 ft	646 km/h /10.150 m	344 kn/33,300 ft	637 km/h /10.150 m
Basic speed at 25, 000 ft (1)	306 kn	567 km/h	318 kn	589 km/h	313 kn	580 km/h
LANDING WEIGHT	82,579 lb	37.457 kg	79,037 lb	35.851 kg	82,579 lb	37.457 kg
Ground roll at SL	2,200 ft	671 m	2,120 ft	646 m	2,200 ft	671 m
Total from 50 ft	2,950 ft	899 m	2,840 ft	866 m	2,950 ft	899 m

Further reading

• Boeing B-29 Superfortress Specifications (1950)
• Boeing B-29A Superfortress Specifications (1950)
• Boeing B-29B Superfortress Specifications (1950)
• Boeing KB-29P Superfortress Specifications (1951)
• Tupolev Tu-4 Standard Specification & Performance
• Boeing B-29 Superfortress Facts: 11 things to know

Bibliography

• B-29 Superfortress in detail & scale, Part 2 by Alwyn T. Lloyd
• The B-29 Superfortress: A Comprehensive Registry of the Planes and Their Missions by e Robert A. Mann
• SB-29 Superfortress Standard Aircraft Characteristics 15-JUN-1954, Air Materiel Command, U.S. Air Force
• “Operation Splash” by Frank W. Penniman, Life of the Soldier and the Airman, U.S. Army, 1948