Free tool · Turbine and fan blades
Weigh the blades, enter the moments, and get a slot-by-slot fitting order with the lowest residual unbalance, or set the blades to cancel a known disk unbalance. Free, instant, and your blade data never leaves your browser.
Free tool · Turbine and fan blades
Weigh the blades, enter the moments, and get a slot-by-slot fitting order with the lowest residual unbalance, or set the blades to cancel a known disk unbalance.
Moment = blade mass × CG radius. One common radius is used for every blade.
Slots are equally spaced. Slot 1 is 0°. All angles are measured from slot 1 in the direction the slots are numbered.
Leave the disk at 0 to pattern the blade set on its own. Enter the disk's measured unbalance (as a moment, same unit) and the blades are set to oppose it.
Odd blade count: slots and 1 are next to each other and both heavy.
| # | Blade ID | Moment |
|---|
Two columns (ID, value) or one column of values. Tab, comma, semicolon or space separated. Header rows are skipped.
USB scales set to keyboard output: click in the box and press the print key on the scale. Each reading is added as the next blade. You can also type a value and press Enter.
Direct connection works in Chrome or Edge on a PC. In other browsers, set the scale to keyboard output instead.
Vectors are drawn to one scale, shown on the ring.
| Slot | Angle ° | Blade ID | Moment | Δ mean | H/L |
|---|
Each blade is a moment vector pointing out along its slot. The blade-set residual is the vector sum of all blades. Moving a blade to another slot changes that sum, and the program searches the arrangements for the one where blade residual + disk unbalance is closest to the goal (zero, or the residual you set).
The search starts with heavy blades spread opposite each other, then improves the order by swapping pairs (simulated annealing with repeated restarts, then a full pairwise check). It is seeded, so the same data gives the same pattern every time. "Search harder" tries a new starting point and keeps the better answer.
Any residual below the resolution of your weighing is effectively zero. A disk unbalance must be expressed as a moment in the same unit as the blades (for example g·mm = grams × radius in mm).
FAQ
Choosing which slot each blade goes in, so that the small weight differences between blades cancel out around the disk. A good pattern leaves the lowest residual unbalance in the blade set, or sets the blades to oppose a known disk unbalance.
No. The calculation runs in your browser and your blade list is saved only in that browser, so you can close the page and come back to it. Nothing is sent to us.
Yes. Choose dead weight × CG radius and enter each blade's mass with one common centre-of-gravity radius. The tool works out each blade's moment as mass × radius.
Yes. Tick alternate heavy and light blades: the heaviest half goes in the odd slots and the lightest half in the even slots, then the order within each half is set for the lowest residual.
Yes. Scales set to keyboard output add each reading as the next blade when you press print on the scale. RS-232 and USB serial scales can be connected directly in Chrome or Edge on a PC.
Balancing blades and disks?
Tell us about the rotor and the tolerance you need, and we'll come back to you with the right machine.
