Firefighters have tackled a blaze which broke out at UAV Engines Ltd in Shenstone.
Two crews from Lichfield and one from Aldridge in the West Midlands attended the incident on Lynn Lane.
The fire is believed to have been caused by a fuel leak in the test rig and has been classed as accidental ignition.
Firefighters used two breathing apparatus, one main jet and positive pressure ventilation to put the blaze out.
The damage was contained to the development bay and the site had been evacuated prior to the arrival of crews.
Staffordshire Fire and Rescue Service will be working closely with the owners of UAV Engines Ltd to give advice and information to prevent similar incidents occurring in the future.
The call was received at 4.29pm on Monday, January 6 and crews left the scene at 7.11pm that evening.