Principal Thermal Engineer

Job Description:

Your impact

You’ll work at the heart of multidisciplinary project teams, advising on thermal performance and ensuring our products meet demanding environmental and operational requirements. This role is ideal for someone with a strong analytical mindset, a flair for problem-solving, and the ability to manage complex interdependencies across multiple programmes and business units.

Leonardo is seeking an experienced Thermal Engineer to play a key role in the development and production of leading-edge Defence products within Land, Naval, Seeker and Space domains supporting both new innovations and proven legacy products.

The successful candidate will be responsible for conducting Thermal Analysis, communicating the results and advising on all aspects of Thermal Engineering activities. The role will involve working with multi-discipline project teams and our Customers across the UK.

What you’ll do:

• Conduct thermal analysis of mechanical designs to assess performance and safety using thermal analysis software, CFD techniques, and classical hand calculations.
• Provide expert guidance on cooling strategies and recommend thermal design improvements as required.
• Advise on materials and manufacturing techniques with an emphasis on thermal performance and mechanical integrity.
• Define thermal requirements and develop methods for verifying compliance across Leonardo products.
• Drive innovation in thermal design, introducing new technologies and methodologies.
• Support product development through all phases—from design and testing to final certification.
• Deliver thermal solutions that meet performance requirements on time and within budget.
• Contribute to technical documentation, including material for peer reviews and stage/gate approvals.
• All members of the Analysis Team are encouraged and supported to continually develop their skills, including (but not limited to) Structural, Thermal, Pressure and Model Driven domains.
• This role is located at our team facility but may require occasional travel to our other UK sites.

What you’ll bring:

• Degree in Mechanical or Aeronautical Engineering
• Post-graduate experience in Thermal engineering. Proven expertise in thermal analysis, with a track record of developing equipment for challenging and extreme operating environments.
• Proficiency in CFD tools, preferably Ansys Icepak and Ansys Fluent, alongside a solid foundation in classical hand calculation methods.
• Experience of environmental test methods for design verification and working knowledge of design certification for land based and airborne equipment.
• Knowledge of Regulatory Standards including but not limited to: Def Stan 00-970, Health and Safety HSE Regulations including Hazardous Waste Regulation. Compliance with Pressure Equipment Regulation, Pressure System Safety Regulation and Fluorinated Gas Regulations.
• Awareness of equipment safety compliance requirements, including the ability to support inspection processes and generate fault and failure reports.
• Excellent verbal and written communication skills with the ability to influence the direction of both internal and external customers.
• A proven problem solver with a practical, pragmatic approach.
• Ability to take ownership of work packages, planning and scheduling own workload and the work of others.

Desirable:

• It is advantageous for the candidate to have experience in the design, development and test of electronics packaging and/or aerospace equipment.
• Experience of manufacturing and joining techniques, engineering material properties.
• Professional recognition as a Chartered Engineer and full membership of a relevant engineering institution (e.g. IMechE)

This is not an exhaustive list, and we are keen to hear from you even if you might not have experience in all the above. The most important skill is a good attitude and willingness to learn.

Working Pattern:

Onsite regularly, up to 5 days a week (37 hours standard work week, overtime if approved by project and employee) to delivery security classification and role specific tasks for projects. The company allows hybrid working so working from home is possible when project work allows.

Basildon is the primary location option but Southampton or Bristol is possible.

Security Clearance

This role is subject to pre-employment screening in line with the UK Government’s Baseline Personnel Security Standard (BPSS). An additional range of Personnel Security Controls referred to as National Security Vetting (NSV) and ITAR may apply, this could include meeting the eligibility requirements for The Security Check (SC) or Developed Vetting (DV). For more information and guidance please visit:

Life at Leonardo

At Leonardo, our people are at the heart of everything we do. We offer a comprehensive, company-funded benefits package that supports your wellbeing, career development, and work–life balance. Whether you're looking to grow professionally, care for your health, or plan for the future, we’re here to help you thrive.

• Time to Recharge: Enjoy generous leave with the opportunity to accrue up to 12 additional flexi-days each year.
• Secure your Future: Benefit from our award-winning pension scheme with up to 15% employer contribution.
• Your Wellbeing Matters: Free access to mental health support, financial advice, and employee-led networks championing inclusion and diversity (Enable, Pride, Equalise, Armed Forces, Carers, Wellbeing and Ethnicity).
• Rewarding Performance: All employees at management level and below are eligible for our bonus scheme.
• Never Stop Learning: Free access to 4,000+ online courses via Coursera and LinkedIn Learning.
• Refer a friend: Receive a financial reward through our referral programme.
• Tailored Perks: Spend up to £500 annually on flexible benefits including private healthcare, dental, family cover, tech & lifestyle discounts, gym memberships and more.
• Flexible working: Flexible hours with hybrid working options. For part time opportunities, please talk to us about what might be possible for this role.

For a full list of our company benefits please visit our website.

Leonardo UK operates a grade-based salary framework with broad bands. The salary range shown reflects the approved grade band for this role, or a narrower hiring range published within that band, and is benchmarked against the external market. Exceptions above the standard range are managed through governance controls to protect internal equity.

Leonardo is a global leader in Aerospace, Defence, and Security. Headquartered in Italy, we employ over 53,000 people worldwide including 8,500 across 9 sites in the UK. Our employees are not just part of a team—they are key contributors to shaping innovation, advancing technology, and enhancing global safety.

At Leonardo we are committed to building an inclusive, accessible, and welcoming workplace. We believe that a diverse workforce sparks creativity, drives innovation, and leads to better outcomes for our people and our customers. If you have any accessibility requirements to support you during the recruitment process, just let us know.

Primary Location:

GB - Basildon

Additional Locations:

GB - Bristol - Coldharbour Lane, GB - Southampton

Contract Type:

Permanent

Hybrid Working:

Hybrid

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