I was looking for ways to get Winlink working without hauling my Win laptop around. (I haven't had good luck with Winlink on a Pi so far.)
However, there is a "pre-release" app in the Google Play store that gives you pretty full functionality for Winlink using an Android device.
It's called: WoAD - link: https://play.google.com/store/apps/details?id=com.sumusltd.woad&hl=en_US&gl=US
I am able to use WoAD to send and receive Winlink emails, using packet through my cheap Baofeng HT and a Mobilinkd TNC. The phone connects to the TNC via Bluetooth and connects well using normal VHF packet mode. WoAD also provides for other Winlink modes (Pactor, even VARA FM) but I haven't tried those yet.
It's a cool solution to make a super portable Winlink setup.
73
Tom