Boeing Stearman N2S Kaydet air ambulance, a variant of the Model 75 trainer aircraft.
https://diqn32j8nouaz.cloudfront.net..._ambulance.jpg
Previously:
https://www.homemadetools.net/forum/...062#post160723
https://www.homemadetools.net/forum/...316#post158023
https://www.homemadetools.net/forum/...581#post155292
