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
![All Other ALL Truck Equipment, APU (Auxiliary Power Unit) OEM# 20702147 in Sioux Falls, SD #24760117 All Other ALL Truck Equipment, APU (Auxiliary Power Unit) OEM# 20702147 in Sioux Falls, SD #24760117](https://webp.heavytruckparts.net/full_image/All-Other_ALL_Truck-Equipment,-APU-(Auxiliary-Power-Unit)_1821960_3_24760117_1.webp)
All Other ALL Truck Equipment, APU (Auxiliary Power Unit) OEM# 20702147 in Sioux Falls, SD #24760117
![Timer Relay, Icstation Delay Relay DC 5V-30V Time Delay Switch 12V 24V 10A Programmable Relay Switch Module LED Display Digital Time Cycle 0.1s-999mins ON-Off Control for Light Water Pump Engine: Amazon.com: Tools Timer Relay, Icstation Delay Relay DC 5V-30V Time Delay Switch 12V 24V 10A Programmable Relay Switch Module LED Display Digital Time Cycle 0.1s-999mins ON-Off Control for Light Water Pump Engine: Amazon.com: Tools](https://m.media-amazon.com/images/I/71upOYrJpkL.jpg)
Timer Relay, Icstation Delay Relay DC 5V-30V Time Delay Switch 12V 24V 10A Programmable Relay Switch Module LED Display Digital Time Cycle 0.1s-999mins ON-Off Control for Light Water Pump Engine: Amazon.com: Tools
![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
![Auxiliary power supply|Transportation Systems Products|Transportation Systems|Products Information|Toyo Denki Seizo K.K. Auxiliary power supply|Transportation Systems Products|Transportation Systems|Products Information|Toyo Denki Seizo K.K.](https://www.toyodenki.co.jp/products/transport/train/img/mow-position.jpg)