Hey Guys,
just discovered the new released version of riftcat / vridge for the GearVR.
While I was checking out what is possible, I discovered that you can use the “VR Preview” functionality of the editor!
They have an instruction on their blog how to install the app on the samsung phone. pretty simple usage with sideloadvr. works like a charm. demo version is enough for testing. I bought it after I discovered the UE functionality 
So…That is amazing for GearVR Devs and if you don’t can’t afford a headset like the oculus.
VRidge and Unreal: (thanks to the guy who made that video!)
credits for the hint to the feature go to: lennys unreal
Have fun!