Charles is available for hire
Hire CharlesCharles Bert Spellman
Verified Expert in Engineering
Mechanical Engineer and Developer
Huntertown, IN, United States
Toptal member since February 24, 2025
Expertise
Bio
Charles is a mechanical engineer with over two decades of experience. He is an expert in magnetic-based sensor design and traditional mechanical design. Proficient in simulating magnetic fields and transducer responses across diverse software platforms, Charles constructs analytical and numerical models to evaluate design space trade-offs within systems and systems of systems.
Portfolio
Therma-Tru
3D Simulations, Data Acquisition (DAQ)
Sensata Technologies
Magnetic FEA
AAR
SOLIDWORKS, Computational Fluid Dynamics (CFD), 3D Simulations
Experience
- Magnetic FEA - 20 years
- 3D Simulations - 20 years
- Analysis - 20 years
- MATLAB - 20 years
- FEA - 20 years
- Automotive Design - 20 years
- PTC Mathcad - 10 years
- COMSOL - 8 years
Availability
Part-time
Preferred Environment
Slack
The most amazing...
...thing I've designed is a rotary position sensor for a variable lift camshaft actuator.
Work Experience
Principal Engineer
2016 - 2019
Therma-Tru
- Enhanced a flow visualization technique by adjusting charge locations to reinforce a new door design, resulting in successful testing on the first try. This achievement ensured the timely launch of a multi-million-dollar project.
- Applied sound engineering principles in data, test, and design analysis.
- Guided laboratory toward data acquisition techniques and equipment.
- Enhanced engineering capabilities by example and suggestion.
Technologies: 3D Simulations, Data Acquisition (DAQ)
Senior Engineer
2014 - 2016
Sensata Technologies
- Assisted in new business development by defining design and architecture parameters.
- Mentored less senior engineers to develop analytical approaches to design and problem-solving.
- Met with customers to discuss their needs and product requirements.
- Contributed to bid activity by creating concept designs, developing a bill of materials (BOM), drafting compliance matrices, and presenting technical details of concepts.
Technologies: Magnetic FEA
Lead Engineer
2013 - 2014
AAR
- Defined, designed, and integrated a multi-shelter communication free-of-charge (FOC) site.
- Performed thermal and CFD simulations using Flow from SOLIDWORKS.
- Developed vibration and shock analysis with Mathcad.
- Tracked weight budget using Excel and VBA to allocate equipment loads across different shelters.
Technologies: SOLIDWORKS, Computational Fluid Dynamics (CFD), 3D Simulations
Senior Engineer and Scientist
2012 - 2013
LogiCore
- Conducted reliability analysis on mean time between failures for helicopter maintenance.
- Studied defense department acquisition and procurement procedures.
- Supported proposal activity with technical expertise.
- Supported proposal activity as a capture manager, establishing external contacts to assemble a team for the Department of Defense (DOD) contract awards.
Technologies: Aerospace & Defense
Principal Multidiscipline Engineer
2011 - 2012
Photon Research (acquired by Raytheon)
- Supported quote response activity by researching needs and defining equipment, materials, and labor.
- Assisted in the construction and outfitting of a ground station for intelligence, reconnaissance, and surveillance projects.
- Utilized SOLIDWORKS CAD to create drawings and models for documenting design and construction processes.
Technologies: Aerospace & Defense, SOLIDWORKS
Principal Mechanical Engineer
2008 - 2011
BAE Systems
- Engaged in multiple short suspense studies involving simulation, design, trade studies, and analysis of customer requests using Mathcad, MATLAB, SOLIDWORKS, and COMSOL Multiphysics.
- Incorporated simulations to optimize weight and volume for a battery and generator system within the constraints of mobile high-energy laser system engagement scenarios.
- Developed a high-energy laser lethality model with a non-stationary laser aim point utilizing COMSOL Multiphysics.
- Created an analysis of the optical path difference within the exit window of a high-power laser system.
- Led the design and construction of a high-power laser lab at the High Energy Laser System Test Facility (HELSTF) on White Sands Missile Range (WSMR).
- Documented and presented findings at different government and customer levels through presentations and white papers.
- Created and supported systems engineering documentation for the SSLTE project, including requirements definition, technical planning, coordinated design reviews, and risk management.
Technologies: Aerospace & Defense, 3D Simulations
Senior Mechanical Engineer
2006 - 2008
Siemens VDO (acquired Continental)
- Developed system-level understanding of customer requirements for automotive transmission control and design concepts to achieve customer's goals.
- Participated in coordination meetings among various internal departments and with customers as designs evolved. Acted as a liaison between European staff and NAFTA customers.
- Created new design concepts leading to eight patent disclosures. Helped establish and verify sufficient engineering resources allocated to the project.
- Assisted other engineers in product development through analysis and practical experiences. Generated Pro/ENGINEER models and conducted Mechanica simulations on solder joints, packages, board deflections, and stresses.
- Created Mathcad heat transfer models for finned electronic housing.
Technologies: 3D Simulations
Staff Engineer and Magnetics Expert
2002 - 2006
Siemens VDO
- Devised cost-effective technical solutions in response to customers' requests for quotations regarding magnetic sensors.
- Met with customers and internal department managers to ensure that design progress aligned with customer goals and allocated adequate resources to the project.
- Led the technical interface with Old Dominion Applied Research Center to investigate the magnetoelastic effects of a torque sensor. Collaborated with the design team to develop an embedded controller for output linearization.
- Supported new development projects and directed the activities of technicians and other engineers.
- Performed magnetic analysis, mechanical analysis, modeling, and simulation to develop new concepts.
- Collaborated with product engineers to guide and support project activities.
Technologies: 3D Simulations
Senior Mechanical Engineer
1995 - 2002
Philips (acquired by Siemens VDO)
- Created and maintained product development schedules. Coordinated product launch activities between engineering, purchasing, manufacturing, and suppliers to ensure timely issue resolution.
- Reviewed technical details to improve the value of produced products. Transferred technical documentation and knowledge for three purchased product lines, producing over four million sensors annually.
- Conducted magnetic and mechanical analyses, performed product cost studies, and liaised with various levels of customers' engineering teams.
- Collaborated and directed manufacturing engineering efforts in Mexico and the United States.
- Implemented and advocated for the use of geometric dimensioning and tolerancing (GD&T).
- Supervised the activities of technicians and other engineers.
Technologies: Automotive Design, 3D Simulations
Chief Engineer
1993 - 1995
Dekko Automotive
- Oversaw a technical staff of seven, providing guidance for the development of engineering department timelines for product and manufacturing development.
- Ensured technical staff was trained and actively working on highest priority needs.
- Calculated development cost models for quote activities.
- Administered technical direction of division and development of project design concepts.
- Collaborated with VPs to establish project goals and communicated with the purchasing department regarding material costs.
- Evaluated sensor concepts using mechanical and magnetic finite element analysis (FEA).
Technologies: 3D Simulations, Management
Senior Mechanical Engineer
1982 - 1993
Magnavox (acquired by Philips)
- Developed sensors and electronic packaging for automotive ignition systems.
- Performed mechanical and magnetic analyses using traditional and FEA techniques.
- Contributed to system definition discussions and trade-off analysis.
- Coordinated with project control, purchasing, customers, and other internal departments.
Technologies: 3D Simulations, Analysis
Experience
Rotary Position Sensor
Created models and simulations of rotary magnetic sensors using Ansoft magnetostatics FEA, MATLAB, and Excel VBA. I utilized and helped develop state-of-the-art magnetoresitive technology to enable the customer to launch a new engine platform. Simulations needed verification to assure customers of the product's anticipated performance under real-world conditions.
RESULTS
Successful model development helped overcome supplier quality issues and fabricate a calibration process to improve end-of-line yields. The customer experienced market success and has converted the entire engine family to the new engine type.
RESULTS
Successful model development helped overcome supplier quality issues and fabricate a calibration process to improve end-of-line yields. The customer experienced market success and has converted the entire engine family to the new engine type.
Steering Angle Sensor
Developed a new and unique steering angle sensor. The sensor utilized plastic harmonic gearing and a special two-pole magnet, allowing a rotational sensor to measure the steering column's multi-turn output.
RESULTS
We achieved two patents and provided the most economical solution for a customer quote request. However, these innovations were not taken into production due to insufficient funding after the company's acquisition.
RESULTS
We achieved two patents and provided the most economical solution for a customer quote request. However, these innovations were not taken into production due to insufficient funding after the company's acquisition.
Transmission Mechatronics Module
Formulated an electronics packaging technique by exploring using STABLCOR carbon composite as a laminate in a multilayer PCB to align the coefficient of thermal expansion (CTE) between the silicon die and the PCB for chip-on-board processing. I utilized Pro/ENGINEER, Mechanica, FEMLAB, Mathcad, and Excel to create models, simulations, and analytical models for studying the concept.
RESULTS
I developed tools that leveraged CTE based on laminate thickness and the impact of module attachment locations to forecast CTE at the electrical component interface. These tools were instrumental in crafting a distinctive electronics module for extreme temperature (>150°C) environments.
RESULTS
I developed tools that leveraged CTE based on laminate thickness and the impact of module attachment locations to forecast CTE at the electrical component interface. These tools were instrumental in crafting a distinctive electronics module for extreme temperature (>150°C) environments.
Laser Exit Window Study
Investigated optical path distortion caused by the interaction of a high-power laser beam and exit window of the pointing system. I employed a unique approach to assess the heating and resulting thermal expansion of the window using the COMSOL Multiphysics trial package.
RESULTS
I explored various laser beam intensity profiles and persuaded the company to purchase the COMSOL Multiphysics package.
RESULTS
I explored various laser beam intensity profiles and persuaded the company to purchase the COMSOL Multiphysics package.
Education
1977 - 1991
Master's Degree in Mechanical Engineering
Purdue University - West Lafayette, Indiana, United States
Certifications
JULY 1987 - PRESENT
Professional Engineer
State of Indiana
Skills
Tools
Slack, SOLIDWORKS, MATLAB, PTC Mathcad, COMSOL
Languages
Excel VBA
Paradigms
Management
Other
Mechanical Engineering, 3D Simulations, Magnetic FEA, Automotive Design, Analysis, FEA, Computational Fluid Dynamics (CFD), Aerospace & Defense, Data Acquisition (DAQ), FEMLAB
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