A tail that lifts down - you are not the first to do this. I believe if you check out a Lockheed C-130 carefully, they do it too. Actually most conventional aircraft have downforce from the tail when the aircraft is in level unaccellerated flight. Draw out the force diagram of the center of lift and the center of gravity and you will see which way the lift from the tail has to go.

As far as a "scale"detail - Please. The R3 is fictional, never sprang forth from the Grandville Brothers shop.