Boom Supersonic is a company whose aim is to redefine commercial air travel by bringing sustainable, supersonic flight to the skies. With the goal to make Mach 2.2 commercial airliners a reality in the near future, their measurement allowances are naturally extremely tight. Verisurf has provided Boom with a software platform that allows crossovers for all their measurement processes.
The Overture, Boom Supersonic’s commercial airliner design, is yet to be produced, though testing has begun on the completed 1/3 scale proof of concept called XB-1. My colleague Sam covered the advanced construction technologies used for XB-1 back in 2020, which you can read here. Besides the useful testing experience of building and flying a 1/3 scale prototype, the XB-1 also helped Boom in determining the best practices in manufacturing, quality verification, bench testing, assembly guidance, process control, and team development: a perfect preparation for the Overture.
“For many engineers the term measurement or metrology is synonymous with inspection and quality verification. At Boom we are no different, but we also embrace metrology as a means to build quality into everything we do,” said Ryan Bocook, manufacturing engineering lead. It was clear from the start that a wide range of measurement solutions would be needed throughout the design and manufacturing process.
“It was our goal from the beginning to develop manufacturing techniques and processes in parallel with the production of XB-1. This required absolute documentation, process control, reporting, and solid data management from the get-go, which led us down the path of Model-Based Definition (MBD),” said Bocook.
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Chief test pilot, Bill Shoemaker, conducts ergonomic test in the carbon fiber, XB-1 nose bay sub assembly.
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Finished horizontal composite tail section with machined core.
Having adopted an MBD strategy, 3D CAD models become the basis for all information necessary to manufacture components. Everything is included in the CAD model, from design to manufacturing, and all Geometric Dimensioning & Tolerancing (GD&T) data. As Verisurf puts it: “The use of MBD and its contributing counterparts, model-based measurement and inspection maintain the all-important digital thread (aka the digital twin).” This means practically every aspect of a component can be measured and compared with the CAD model. “At Boom we maintain the 3D CAD model as the authority, which removes ambiguity, conflict and doubt that arise when drawings and models co-exist. With authority bestowed on the model, MBD eliminates errors that result from referencing an incorrect source and makes processes more efficient,” added Bocook.
A common measurement and inspection platform
Boom’s model-based measurement and inspection strategy covers every department within the manufacturing enterprise, including design, manufacturing, shipping/receiving, assembly, and quality inspection. In order to effectively manage the breadth of measurement and inspection needs, Boom determined the following solution requirements:
- A single measurement software needs to drive all metrology processes, including quality inspection, reverse engineering, tool building, and assembly guidance
- Software must interface with and control a variety of portable measurement devices, including arms and trackers
- Software must be model-based on a CAD platform for flexibility in managing files, creating and executing model-based inspection
- Software must be able to import and allow editing of intelligent GD&T data to quickly create inspection routines
- Software must handle a range of inspection data, from manual probing to noncontact scan data
Applied measurement
The old adage “If you can’t measure it you can’t monitor it” holds true at Boom. Virtually every part is subjected to quality verification—100% inspection. “We are using measurement and inspection software all over this aircraft, I doubt there is a single part that hasn’t been probed or scanned,” said Wyatt. Boom uses model-based measurement and inspection in new and creative ways to effectively shave hours, days, and weeks off critical processes while actually improving on the end results. Model-based measurement and inspection is a critical component in designing, reverse engineering, inspecting and scanning of flight hardware and test articles, including:
- Inspection of Tooling and Finish Parts
- Reverse Engineering
- Tooling Design and Validation
- Off Aircraft Test Setup
- On Aircraft Part Locating
Inspection of tooling and finish parts from suppliers
MBD software is also used by Boom to verify outsourced components and to validate first article inspection reports provided by suppliers. Virtually any internally produced or outsourced part can, and is, measured.
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Composite tooling inspection and part validation using Verisurf software.
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Inspection of incoming composite tool using Verisurf software.
Verisurf Software was chosen by Boom for a number of reasons, such as its open CAD-based architecture, which is able to work with and drive virtually all hardware measuring devices. “Verisurf software serves as a common measurement platform for Boom and communicates openly with all our CAD files and those used by our vendors,” said Todd Wyatt, metrologist. “We realize improved quality and efficiency while reducing our direct cost by standardizing on a common platform. All our users are trained on a single measurement and inspection software and we are only supporting one software from a licensing, data management, and maintenance point-of-view.”
Reverse Engineering
Even for a ground-up designed XB-1, many COTS (Common Off The Shelf) components were used, mainly in order to reduce the time it would take to build the proof of concept aircraft. The biggest example is the engines, which are GE J-85-15 engines. With the lack of a good model of critical interface points for these engines, it was necessary to reverse engineer certain locations of features on them. These included engine mounts, gear drive shaft, fuel manifolds and air ducting. This was accomplished by scanning the exterior of the engine, from which a basic clearance model could then be made for bulkheads, nacelles and other systems to ensure proper fit in tight spots.
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Reverse engineered ducting and mounting assembly using Verisurf software.
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Reverse engineered engine assembly model using Verisurf software.
Tooling design and validation
Because only one XB-1 would ever be made, tooling needed to be generated quickly and at a low cost. Using scanning or probing, paired with 3D printing, it was possible to design and generate tools in a matter of hours. In addition to this, the measurement and inspection software was used to compare composite tooling to the 3D CAD model prior to layup, an essential task as much of the XB-1’s structure is made from composite material.
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Horizontal tail test fixture model using Verisurf software.
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Pitch actuation test fixture model using Verisurf software.
Best fit analysis
A good example of a one-off composite part build for XB-1 is the horizontal tail (HT assembly). Measurement software played a critical role in creating custom surfaces based off actual manufacturing tolerances. The process to build the HT assembly consisted of:
- The upper skin of the horizontal tail was laid up in the tool.
- The B side of that composite skin was scanned while in a vacuum chuck holding the part contour to the tool.
- The measurement software was used to create NURBS (Non-uniform rational B-spline) surfaces of the actual produced B side of the composite part.
- The NURBS surface was then used to trim the core model to the actual scan and a CNC program was generated for machining of core to match the actual part profile.
- The machined core was then bonded to the outer skin B side.
- The lower skin was laid up and scanned.
- In the same fashion as the outer skin process, the scans of the actual part is then used to machine the bonded core to match the closeout skin exactly.
- Finally, the close out skin can be bonded, and the horizontal tail sandwich construction is near complete.
Off aircraft test setups
Rather than testing the aircraft as a whole first time, several components were tested separately, or ‘off aircraft.’ The model-based measurement software was used to locate components prior to fixing them and to validate that they aligned properly. For example, the horizontal tail torque tube axis was precisely aligned using the measurement software and welded in place during setup. The pitch rig, which includes several parts located in 3D space, were also accurately aligned and welded in position. The aileron test rig was also set up using the measurement software to locate all parts per the CAD model.
On aircraft part location
The model-based measurement software was instrumental in making assembly tooling simple and inexpensive, which was a necessity due to the one-off nature of the XB-1 build. The software eliminated the need for precise assembly fixtures and allowed for flexibility in installing components in 3D space. Laser trackers and arms were used by the software to precisely locate and place parts into position during assembly.
Using laser trackers, CAD model-based measurement is used for wing positioning during final assembly. This method provides precise assembly guidance without the time and cost associated with building assembly fixtures.
“Model-based measurement and inspection software plays a critical role in the fabrication and assembly of XB-1, from part inspection, to tooling, setup and validation, to reverse engineering, creating fixtures, and ultimately the assembly of the aircraft. Today’s measurement software is easy to use and easy to learn; it has found its way into virtually every design/build process at Boom,” said Wyatt. “Without it the aircraft build would be slower, more expensive and less precise.”
XB-1 was successfully completed and unveiled back in 2020, and ground tests have begun, with the first flight tests expected soon.