Helicopter Vertol model 44С - s/n 147 N74056.  (civil version of the Piasecki H-21C."Work Horse")
Aleksandr Markin
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/33104187@N04/13561296264/">Helicopter Vertol model 44С - s/n 147 N74056.  (civil version of the Piasecki H-21C."Work Horse")</a>