What lifter type do radial engines typically have?

What lifter type do radial engines typically have?

• A. Solid lifters.
• B. Hydraulic lifters.
• C. Roller lifters.
• D. Magnetic lifters.

Answer: (A)

Radial engines typically use solid lifters. This keeps valve clearance fixed and valve timing stable across the wide temperature changes and high vibration these engines experience. Hydraulic lifters rely on oil pressure to auto-adjust clearance, which can lead to inconsistent valve timing if oil pressure fluctuates—unacceptable in aircraft operation where reliability is critical. Roller lifters add complexity and weight, which isn’t needed in the traditional radial valve train, and magnetic lifters aren’t used in standard aircraft piston engines. So the straightforward, robust choice for radial engines is solid lifters.

Radial engines typically use solid lifters. This keeps valve clearance fixed and valve timing stable across the wide temperature changes and high vibration these engines experience. Hydraulic lifters rely on oil pressure to auto-adjust clearance, which can lead to inconsistent valve timing if oil pressure fluctuates—unacceptable in aircraft operation where reliability is critical. Roller lifters add complexity and weight, which isn’t needed in the traditional radial valve train, and magnetic lifters aren’t used in standard aircraft piston engines. So the straightforward, robust choice for radial engines is solid lifters.