Case Study: HONEYWELL for the Recommissioned B-52H’s

Re-Manufacturered for Better Performance, Higher Resistance to Extremes & Vibration.

PRODUCT OVERVIEW

Originally Designed in the 50’s, Updated to 2016 Standards
Unique Design Features Make Oil Coolers Manufacturable
Innovative Production Techniques Improve Final Product
Heavy-duty Construction Insures Length of Service

The original design for the B-52 Bomber Oil Cooling system was invented more than 60 years ago. Now that the aircraft are being re-commissioned, replacements had to be created. ACE was chosen because of our reputation for excelling with difficult metal milling, forming and assembly.

Production began by studying the form with our 3D printer. Once the shape and edges were determined, our manufacturing engineers “flattened” the design. Once programmed into our large-platform CNC machines, operators milled fine grooves on the face on a 1” slab of pure aluminum. These “fins” maximize the cooling effect of air passing over the surface. This technique required some practice rounds to get to a thickness where the metal fins wouldn’t tear or crumple.

Once the panels were completed, a hard wax was used to fill-in the space between the grooves. This prevented crushing the fins during forming the flat panel into a curved section. A back panel was also formed to attach over small cells in the back, through which oil flows and is cooled.

A custom stand, or fixture, was designed and built for the curved units for final assembly work, welding, and finishing.

The B-52H Oil Coolers are curved to an exact arc, and when joined end-to-end, they wrap completely around the inside perimeter of the engine nacelle, where airflow is at its peak – cooling the oil travelling through the cells, inside.

Several early runs were required to learn the best techniques for cutting the grooves without tearing the fins.
Once milled, the back was laid with cells which enabled better cooling of the oil.
Once complete, a cover held these cells in place.
Before and After: a special hard wax was heated and poured into the grooves. The wax kept the fins intact during forming the units into the final curled shape. Once complete, the units were heated and the wax removed.
A special tooling stand was engineered to hold the oil coolers after curling for the final welding on the backs of the units.
The tooling was on a stand which could be easily rolled through the work centers.
The tooling stands enabled our welders to precisely attach the oil feed tubes on the reverse of the oil coolers at extremely strict tolerances.

MANY STEPS FOR PRODUCTION
A 3D print of the sophisticated shape was key in the production. We used the model for production analysis and determined that to make this part, the curved form had to start as a flat shape for CNC milling. Our 3D-modeling software enabled our manufacturing engineers to flatten the form and precisely plot the outer edges for trimming.

Once the panel was milled, and the outer edge was trimmed, the flat 1″-thick aluminum panel was locked-down to the bed of our large CNC mill, and thin fins were created by carving grooves.

Re-Manufacturered for Better Performance, Higher Resistance to Extremes & Vibration.

PRODUCT OVERVIEW

MANY STEPS FOR PRODUCTION