I hiked down to Cochie Spring from the Wild Burro Trailhead (Marana, Arizona) on Tuesday, July 22, 2025. When I got to the Spring, I took a little break, ate my snack, and looked at the old livestock tanks.
I noticed a label at the end of the large tank.
My interest was piqued because the label referred to the Aircraft Engine Division of the Ford Motor Company and indicated that the tank was an aircraft engine shipping container.
This made me curious, so when I returned home, I used Grok AI to see what I could find out.
The results Grok gave me are amazing!
In summary, here's what I learned. (Augmented with photos and a few other details.) (All the Grok queries and result details follow.)
The Pratt & Whitney R-4360 Wasp Major aircraft engine was shipped in this container:
The R-4360 Wasp Major is a 28-cylinder, air-cooled, four-row radial piston aircraft engine
Displacement of 4,362.5 cubic inches (71.5 liters)
Maximum power output of up to 4,300 horsepower
The largest-displacement aviation piston engine mass-produced in the United States, first run in 1944
The last of the Pratt & Whitney Wasp family
The Pratt & Whitney R-4360 Wasp Major
(https://www.spannerhead.com/2012/08/20/interesting-engines-the-pratt-whitney-r-4360/)
The R-4360-53 variant:
The Convair B-36J Peacemaker used six (6!) of these engines
The Peacemaker was the primary nuclear weapon strategic bomber of the USAF Strategic Air Command (SAC) from 1948 to 1959
Normal power rating of 2,800 horsepower at 2,600 rpm
Military power of 3,500 horsepower at 2,800 rpm (30-minute limit)
Maximum rating of 3,800 horsepower at 2,800 rpm with water/alohol injection (5-minute limit)
Compression ratio of 6.7:1
Required 115/145 aviation gasoline
Equipped with two General Electric BH-1 turbosuperchargers
USAF Convair B-36D Peacemaker (Photo Source: USAF) (https://acesflyinghighthesurvivors.wordpress.com/2018/12/19/the-survivors-convair-b-36-the-ultimate-peacemaker/)
In 1948 the XB-36 dwarfed its predecessor the Boeing B-29 Superfortress! (Photo Source: USAF) (https://acesflyinghighthesurvivors.wordpress.com/2018/12/19/the-survivors-convair-b-36-the-ultimate-peacemaker/)
Aerial view of Convair B-36 Peacemakers at Davis-Monthan AFB in Tucson, Arizona, engines removed and awaiting scrapping (https://www.airplanes-online.com/b36-survivors.htm)
Here are the queries I submitted to Grok and its final results.
My first query:
What kind of aircraft engines did Ford Motor Company make? When and where did they make them? For whom?
My second query:
I encountered and photographed a half-cylinder-shaped steel container about 10 feet wide and 18 feet long with a tag identifying it as an "Aircraft Shipping Container, Metal", Ford Motor Company, Chicago, in the desert near Tucson, Arizona, site of Davis-Monthan Air Force Base. What type of aircraft engine was likely shipped in this container?
My third query (using Google Lens to get the text on the label):
An additional point: the label on the container has the following text:
AIRCRAFT ENGINE SHIPPING CONTAINER METAL
USAF STOCK NO.
0235-P7802
MPRE NO
P7802
CONTRACT NO.
AF-33-038-15871
SENAL NOB-98
SPECIFICATION
MIL-C-5584
CONTAINERS ARE PROPERTY OF US GOVERNMENT AND ARE RE-USABLE
FOR MODEL NOS
R-4360-53-55-57
AIRCRAFT ENGINE DIVISION
FORD MOTOR COMPANY
CHICAGO, ILLIS
- Research suggests the container likely shipped Pratt & Whitney R-4360 Wasp Major engines, specifically variants R-4360-53, R-4360-55, and R-4360-57, produced by Ford Motor Company under license for the USAF.
- The evidence leans toward these engines being used in military aircraft like the Convair B-36 Peacemaker, given the container's location near Davis-Monthan Air Force Base.
- There is some controversy around engine manufacturer attribution, with some sources suggesting confusion with other engine models, but historical records confirm Ford's production of R-4360 engines in Chicago.
The container likely shipped Pratt & Whitney R-4360 Wasp Major engines, a 28-cylinder, four-row radial piston engine with a displacement of 4,362.5 cubic inches and up to 4,300 horsepower. The label specifies variants R-4360-53, R-4360-55, and R-4360-57, which were used in military applications.
Ford Motor Company's Aircraft Engine Division in Chicago produced these engines under license from Pratt & Whitney, as part of USAF contracts like AF-33-038-15871, during the 1950s, aligning with the container's tag.
These engines were likely intended for the United States Air Force, given the USAF stock number and contract details on the label, for use in military aircraft.
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This survey note provides a comprehensive analysis of the aircraft engine likely shipped in the half-cylinder-shaped steel container, 10 feet wide and 18 feet long, tagged as "Aircraft Engine Shipping Container, Metal," Ford Motor Company, Chicago, found near Tucson, Arizona, close to Davis-Monthan Air Force Base. The analysis is grounded in the container's label details, historical records of Ford's aircraft engine production, and the context of its location. The current time is 05:03 PM MST on Tuesday, July 22, 2025, and all information is considered relevant to this timeframe.
The container's label includes the following critical information:
- **USAF STOCK NO.**: 0235-P7802
- **MPRE NO**: P7802
- **CONTRACT NO.**: AF-33-038-15871
- **SENAL NOB-98**
- **SPECIFICATION**: MIL-C-5584
- **FOR MODEL NOS**: R-4360-53-55-57
- **Manufacturer**: Aircraft Engine Division, Ford Motor Company, Chicago, Illinois
- **Ownership**: Containers are property of the US Government and are reusable
The label explicitly states the container was used for shipping aircraft engines, specifically models R-4360-53, R-4360-55, and R-4360-57, and is associated with a USAF contract, indicating military use.
Research suggests the container likely shipped Pratt & Whitney R-4360 Wasp Major engines, specifically the variants R-4360-53, R-4360-55, and R-4360-57. The R-4360 Wasp Major is a 28-cylinder, four-row radial piston aircraft engine, with a displacement of 4,362.5 cubic inches (71.5 liters) and a maximum power output of up to 4,300 horsepower. It was the largest-displacement aviation piston engine mass-produced in the United States, first run in 1944, and was the last of the Pratt & Whitney Wasp family.
- **R-4360-53**: Used in the Convair B-36J Peacemaker, with a normal power rating of 2,800 horsepower at 2,600 rpm, military power of 3,500 horsepower at 2,800 rpm (30-minute limit), and maximum rating of 3,800 horsepower at 2,800 rpm with water/alcohol injection (5-minute limit). It had a compression ratio of 6.7:1 and required 115/145 aviation gasoline, equipped with two General Electric BH-1 turbosuperchargers.
- **R-4360-55 and R-4360-57**: Specific details on these variants are less documented, but they are part of the same family, likely used in similar military applications, with variations in power ratings and configurations for different aircraft.
Historical records, such as those from "This Day in Aviation," confirm the R-4360-53's use in the B-36J, with detailed specifications aligning with the engine's capabilities for heavy bombers.
Ford Motor Company produced these R-4360 engines under license from Pratt & Whitney at its Chicago plant, particularly during the 1950s. The first result from the search confirms that Ford was involved in producing R-4360 engines, with the R-4360-59B being the most numerous variant, with 4,260 engines manufactured in the 1950s, primarily for USAF KC-97 and C-97 aircraft. While the -59B is not listed on the container, it indicates Ford's significant role in R-4360 production, supporting the likelihood that variants R-4360-53, -55, and -57 were also produced there.
The container's tag, "Aircraft Engine Division, Ford Motor Company, Chicago, Illis," aligns with historical records of Ford's operations at the Chicago plant, originally the Dodge Chicago Plant, which was a major wartime and post-war facility for engine production.
The contract number AF-33-038-15871 on the label indicates it was part of a USAF procurement, likely for supplying engines to military aircraft. Searches for this specific contract number did not yield direct results, but the presence of USAF stock numbers and specifications like MIL-C-5584 (a military specification for containers) confirms its military use. The location near Davis-Monthan Air Force Base, known for storing surplus military aircraft, further supports this, as the base housed aircraft like the Convair B-36, which used R-4360 engines.
The R-4360 Wasp Major powered several large military aircraft, including:
- **Convair B-36 Peacemaker**: A strategic bomber with six R-4360 engines, used during the Cold War, with variants like the B-36J using the R-4360-53.
- **Boeing C-97 Stratofreighter**: A military transport derived from the B-29, also using R-4360 engines.
- **Douglas C-124 Globemaster II**: Another heavy-lift transport powered by R-4360 variants.
Given the container's location and the variants listed, it seems likely that these engines were intended for the Convair B-36, given its historical presence at Davis-Monthan and the specific use of R-4360-53 in the B-36J.
Some sources, such as "Interesting Engines: The Pratt & Whitney R-4360 – Spannerhead," mention confusion with other engine models, but historical records consistently show Ford's production of R-4360 engines, not to be confused with the Wright R-3350 Duplex-Cyclone, which was a rival engine used in the Boeing B-29. The label's specificity to R-4360 variants eliminates ambiguity, and the evidence leans toward the Wasp Major.
To provide a clearer picture, below is a table comparing the R-4360 variants and their likely applications:
This table highlights the R-4360-53's detailed specifications and its use in the B-36, with the other variants likely serving similar roles.
Ford's involvement in R-4360 production was part of its broader wartime and post-war aviation efforts. The Chicago plant, originally built by Dodge during World War II, was taken over by Ford in the 1950s, continuing to produce engines like the R-4360 for military contracts. The container's tag, dated to Ford's operation, likely reflects this post-war period, with production peaking in the 1950s, as seen with the R-4360-59B's 4,260 units.
Research suggests that the container likely shipped Pratt & Whitney R-4360 Wasp Major engines, specifically variants R-4360-53, R-4360-55, and R-4360-57, produced by Ford Motor Company under license for the USAF, likely for aircraft like the Convair B-36 Peacemaker. The evidence is strong, supported by the container's label, historical production records, and the location near Davis-Monthan Air Force Base. For further exploration, refer to Pratt & Whitney R-4360 Wasp Major for engine details and R-4360 Operations for Ford's production history.
This analysis provides a comprehensive understanding of the likely contents, grounded in historical and logistical evidence.