From Halopedia, the Halo wiki
The Callipoas-pattern repulsor engine is a pattern of repulsor used on Ceudar-pattern heavy corvettes.
As part of Operation: UPPER CUT during the Fall of Reach, NOBLE Team and other FSS-1000 Sabre pilots disabled the four Callipoas-pattern engines of the Ardent Prayer.
A Ceudar-pattern with Callipoas-pattern engines, confronting the UNSC Infinity.
A Ceudar-pattern vessel with green colored Callipoas-pattern engines over Casbah City.
Ceudar-pattern vessels with paler colored Callipoas-pattern engines at the Corbulo Academy of Military Science.