Free Engineering Tool
Fan Blade Centrifugal Force Calculator
Calculate centrifugal force on fan blades for ID and FD fans. Get force per blade, total force, force-to-weight ratio, and tip speed.
Results
Centrifugal Force on a Fan Blade
- m — blade mass (kg)
- R — distance from axis to blade CG (m) — enter in mm, converted internally
- ω = 2π·n/60 — angular velocity (rad/s)
Force-to-Weight Ratio
Tip Speed
Tip speed is calculated using the blade CG radius. For actual impeller tip speed, use the outer tip radius.
Practical Example
Given: Blade mass = 15 kg, CG radius = 800 mm, Speed = 1485 RPM
ω = 2π × 1485 / 60 = 155.5 rad/s
F = 15 × 0.8 × 155.5² = 290,340 N = 290.3 kN
Force/Weight = 290,340 / (15 × 9.81) = 1,972×
Tip speed at CG = 0.8 × 155.5 = 124.4 m/s
⚠️ Note: These forces are per blade acting on the blade root. The net force on bearings depends on balance quality — ideally, all blade forces cancel. Mass differences between blades create the unbalance force measured during balancing.
Centrifugal force F = m × R × ω², where m is blade mass in kg, R is the distance from rotation axis to blade center of gravity in meters, and ω = 2π·n/60 is angular velocity in rad/s. The result is in Newtons.
Force-to-weight ratio is centrifugal force divided by blade weight (m × g). It shows how many times gravitational force the blade experiences. A ratio of 1,000 means the blade “feels” 1,000× its own weight — critical for blade root stress and fastener design.
Typical limits:
- Carbon steel: 80–120 m/s
- Stainless steel: 60–90 m/s
- Aluminum: 100–150 m/s
- FRP/fiberglass: 60–80 m/s
Higher tip speeds increase centrifugal stress and noise.
ID (Induced Draft) fans handle hot, dirty gas requiring larger, heavier blades at greater radii. Combined with similar or higher speeds, this creates significantly greater centrifugal forces than smaller FD (Forced Draft) fan blades.
Centrifugal force from unbalance (uneven blade mass distribution) causes vibration. Even a small mass difference between blades creates a net force on bearings. Balancing ensures all blade forces cancel, leaving minimal net force at the shaft.
The procedures described on this page were developed and field-tested by the Vibromera team using the Balanset-1A, a portable dual-channel balancer and vibration analyzer for on-site rotor balancing.
Professional field balancing instruments for fans, blowers, and impellers. Reduce vibration and extend bearing life on-site.
Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
