New England Air Museum - The #WhatisitWednesday answer is here! This week we're looking at an Auxiliary Power Unit (APU). The "Putt-Putt" as it is fondly known, is a small gas turbine
![Dual Battery Selector Switch, Safe Convenient Battery Selector Switch Exquisite for 6V 12V, 24V, 32V Power Supply System: Amazon.com: Electronics Dual Battery Selector Switch, Safe Convenient Battery Selector Switch Exquisite for 6V 12V, 24V, 32V Power Supply System: Amazon.com: Electronics](https://m.media-amazon.com/images/I/51dg5zeR7hL._AC_UF894,1000_QL80_.jpg)
Dual Battery Selector Switch, Safe Convenient Battery Selector Switch Exquisite for 6V 12V, 24V, 32V Power Supply System: Amazon.com: Electronics
![Auxiliary Power Units Making Inroads on Fire Apparatus - Fire Apparatus: Fire trucks, fire engines, emergency vehicles, and firefighting equipment Auxiliary Power Units Making Inroads on Fire Apparatus - Fire Apparatus: Fire trucks, fire engines, emergency vehicles, and firefighting equipment](https://www.fireapparatusmagazine.com/wp-content/uploads/2013/04/1304FAapu1.jpg)
Auxiliary Power Units Making Inroads on Fire Apparatus - Fire Apparatus: Fire trucks, fire engines, emergency vehicles, and firefighting equipment
![Uav Auxiliary Equipment T30 Diesel Alternators Air-Cooled Engine Generator Set for T30 Drone - China Generating Set, Air-Cooled Engine | Made-in-China.com Uav Auxiliary Equipment T30 Diesel Alternators Air-Cooled Engine Generator Set for T30 Drone - China Generating Set, Air-Cooled Engine | Made-in-China.com](https://image.made-in-china.com/44f3j00GyHPhiBdbpVf/Uav-Auxiliary-Equipment-T30-Diesel-Alternators-Air-Cooled-Engine-Generator-Set-for-T30-Drone.webp)