A brief preface
Hello and welcome to Heavy Bomber March suggestion #4! This month I’m cranking out suggestions for heavy bombers. Enter the Convair YB-60, an all-jet descendant of the legendary B-36. Specifically, we’ll be looking at the second of two prototypes, s/n 49-2684!
Overview
The Convair YB-60 is an all-jet bomber based on the enormous B-36. Initially designated the B-36G, it soon received its own designation due to the dramatic changes compared to the B-36F. The YB-60 took flight on 18 April 1952, three days after its competitor, the B-52. Despite being substantially cheaper, with Convair even offering to finish under-construction B-36s as B-60s instead at no added cost, the YB-60 lost out to the B-52, the latter being over 160km/h faster at altitude. Combat experience in Korea showed that strategic bomber doctrine needed to change from large, well-defended like the YB-60 to fast, high-flying aircraft like the B-52. One prototype was completed with a second, modified prototype 95% percent complete, only awaiting delivery of engines and minor final assembly at the time the YB-60 was abandoned.
Why the YB-60 s/n 49-2684?
The US has a plethora of cold war jet bombers with massive production quantities and highly eventful service lives. Why suggest the YB-60, let alone the unfinished of the two prototypes? It all comes down to one factor- defensive armament. A single tail turret, even with radar guidance, simply isn’t enough to protect a bomber from interception. IRL this wasn’t seen as an issue- bombers would have fighter support and rely on speed and altitude to evade defenses. However, in War Thunder, this would mean that such bombers are either at a BR where they outrun everything and are XP printers, or they’re at a BR where they don’t and are XP piñatas. 49-2684 meanwhile holds on to most of the turrets of its B-36 ancestor, retaining all-around gun protection at a time where most bombers were giving up most or all of their defenses.
- Yes
- No
History
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Origins- the B-36
The YB-60’s development traces back to the B-36 Peacemaker. Development of the B-36 started in 1941 with the goal of producing an aircraft capable of bombing Germany from American airbases, as insurance should Britain fall. Development of such an enormous project took considerable time and resources, and by the time the B-36 entered service in 1948 its target had shifted from Berlin to Moscow.
The B-36 was a truly monstrous bomber. It had a wingspan 60% longer than the B-29 and weighed over twice as much empty. Pilots described flying the Peacemaker as “sitting on your front porch and flying your house around”. And it wasn’t just big, it was heavily armed, bristling with 8 twin 20mm turrets and carrying a whopping 86,000lbs of ordinance.
The first B-36 models were the unarmed trainer B-36A and armed bomber B-36B. The B-36C was never built so the next variant was the B-36D, which introduced the B-36’s unusual and iconic mixed jet/prop propulsion. The RB-36E was a high-altitude reconnaissance aircraft so the next bomber was the B-36F with improved piston engines, entering production in late 1950.
Development
Development of the YB-60 began as a private venture in August 1950. Initially designated the B-36G, it was based on the B-36F but with swept wings and an 8-jet powerplant shared with the XB-52. Other changes included a redesigned nose section, removal of all but the tail turret, fitting of a tail wheel, and modified avionics. This resulted in an aircraft with over 70% parts commonality with the B-36F, but those 30% were quite significant. As such, the designation was changed to B-60.
Convair was authorized to convert two B-36Fs, s/n 49-2676 and 49-2684, to YB-60s in April 1951. 2676’s conversion was finished by December, though its first flight was delayed until April 1952 due to delays in the shipment of engines. Interestingly, the B-60 was also considered with a turboprop propulsion, but this never left the drawing board.
Evaluation
Initial flight tests of the YB-60 were promising. The aircraft flew well and smooth, with co-pilot Arthur Witchell Jr. reporting the aircraft “rode like a Cadillac”. However, subsequent flight tests were much more troubled. The aircraft was found to have low lateral stability and was prone to engine, electrical, and control issues. Meanwhile, the YB-52 concurrently undergoing testing had no such issues. The YB-60 was considerably cheaper than the YB-52 and had nearly double the payload, but the YB-52 was faster, with a higher ceiling, and more room for growth.
The final nail in the coffin came from Korea. There, American B-29s had proven helpless against Soviet-built MiG-15s, with dozens of B-29s lost to MiGs in exchange for only one MiG shot down. The conflict showed that the age of massive, slow bombers relying on turrets for defense was over, and modern bombers would need to outrun their pursuers. In the context of the testing of the YB-60 and YB-52, the latter was clearly better fit for modern combat.
The YB-60 program would be cancelled in summer 1952 with testing ending in January 1953. Even when Convair offered to complete its remaining contract of B-36s as B-60s for no additional cost, the Air Force declined.
Production Standard- s/n 49-2684
But let’s backtrack a moment. So far, we’ve only been discussing s/n 49-2676. But this suggestion is for s/n 49-2684, the second prototype. It’s tricky to find information on this second airframe. In August 1951 Convair suggested that the second prototype retain the majority of the B-36F’s turrets, with this second prototype being used as the production standard while the first was to be used for evaluation. The Air Force agreed, and this is likely when conversion of the aircraft began. 2684 was intended to be ready for first flight by February 1952- and in fact it was complete at that point except for engines and avionics. With the shortage of J57s and both the 2676 and the YB-52 to compete with, 2684 never received its engines. As early as summer 1952 the Air Force had already made up its mind to purchase the B-52, and the YB-60 program was cancelled even before testing had finished. With a cancelled program, 2684’s hope for seeing flight was over. However, the aircraft would receive a full avionics fit in June 1954. Also in June 1954, the YB-60 prototypes were accepted into service. In July they were scrapped.
Specifications
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Airframe
Length: 53.4m
Span: 62.9m
Height: 15.4m
Wing Area: 486.7m^2
Empty Weight: 69,407kg
Loaded Weight: 118,047kg
MTOW: 185,973kg
Crew: 9
Propulsion
8x Pratt and Whitney J57-P-3 in 4x twin pods
Max Thrust: 33.36kN (each)
Max Thrust (WEP, 30min): 38.70kN (each)
Max Thrust (WEP): 309.60kN (total)
Max TWR: 0.45
Internal Fuel: 156,950L
Internal Fuel Limit, Max Bomb Load: 101,622L
Flight Performance (at 80,739kg, est.)
Max Speed (14.4km): 818km/h (Ma 0.77)
Max Speed (10.7km): 829km/h (Ma 0.77)
Max Climb Rate (sea level): 26.87m/s
Service Ceiling: 15.5km
Armament
Defensive:
2x 20mm M24A1, tail turret
400rpg
832m/s
1,500rpm (total)
2x 20mm M24A1, dorsal turret x2, ventral turret x2
350rpg
832m/s
1,500rpm (per turret)
Offensive:
1x 43,000lb T-12 Cloudmaker- 43,000lb total
3x 22,000lb M110 Grand Slam- 66,000lb total
4x 12,000lb M123 Tallboy- 48,000lb total
12x 4,000lb AN-M56- 48,000lb total
28x 2,000lb AN-M66- 56,000lb total
72x 1,000lb AN-M65- 72,000lb total
132x 500lb AN-M64- 66,000lb total
*nominal weights
Avionics
AN/APG-41 gun radar (tail turret)
AN/APG-32 gun radar (dorsal turrets)
K-3A radar bombing system
AN/APR-4 RWR
AN/APR-9 RWR
AN/APT-6 radar jammer
AN/APT-9 radar jammer
Chaff dispensers
The YB-60 in-game
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The YB-60 s/n 49-2684 carries over much of the characteristics of the B-36 family. While it cannot carry a second T-12 and has less armament, it more than makes up for it with dramatically improved flight performance. And realistically, the 72x 1,000lb load is generally more practical than the 2x 43,000lb load except for GRB. As the last American heavy bomber with substantial defensive armament, it’d probably be the last such aircraft we could see in-game. Sorry, B-52 fans.
Gallery
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49-2676
Some images of the first prototype, which can be distinguished by the nose instrumentation probe. So yes, the cover photo is of the wrong prototype- it’s just too iconic a photo to pass on
YB-60 and B-36
First takeoff
In flight
The tail gear was only used when the aircraft was at low speeds, retracted prior to takeoff and deployed after touchdown
The cockpit
49-2684
Now for the few images of our second prototype
Guns out
Almost complete
Internals
Sources
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Convair YB-60 Standard Aircraft Characteristics- 11 July 1952
Convair B-36
https://www.joebaugher.com/usaf_bombers/b60.html
18 April 1952 | This Day in Aviation
Уголок неба ¦ Convair B-60