How are compressor blades attached to the compressor disks?

How are compressor blades attached to the compressor disks?

• A. Dovetail, bulb, fir-tree
• B. Bolts
• C. Welds
• D. Adhesive bonding

Answer: (A)

Blade attachment relies on the blade roots matching slots in the compressor disk. The common retention styles—dovetail, fir-tree, and bulb—provide a positive mechanical interlock that resists the high centrifugal forces and accommodates different thermal expansion between blade and disk. Dovetail roots slide into corresponding grooves, fir-tree roots use a stepped, tree-like profile for multiple contact surfaces, and bulb roots fit into a bulb-shaped cavity with a locking feature. These geometries keep blades secure and allow for removal and replacement, something bolts, welds, or adhesive bonding cannot reliably provide under the engine’s vibration and extreme temperatures.

Blade attachment relies on the blade roots matching slots in the compressor disk. The common retention styles—dovetail, fir-tree, and bulb—provide a positive mechanical interlock that resists the high centrifugal forces and accommodates different thermal expansion between blade and disk. Dovetail roots slide into corresponding grooves, fir-tree roots use a stepped, tree-like profile for multiple contact surfaces, and bulb roots fit into a bulb-shaped cavity with a locking feature. These geometries keep blades secure and allow for removal and replacement, something bolts, welds, or adhesive bonding cannot reliably provide under the engine’s vibration and extreme temperatures.