I don't think I should be the one to say this, but I also think if I can help you, I will.
I personally tried cardboard as a building material and it didn't go very well, but it flew. This is the link:
Cardboard FT Simple Scout
But it was the FT Simple Scout, and I tried to stay as close to the plane as possible using the same construction techniques as FT, using hot glue. I think the FT Simple Scout is an easier plane to fly than the Spitfire.
The result was a broken plane, a bent engine, and a beaten battery (luckily no damage). And, of course, the hurt pride.
I really used cardboard because where I live I don't have access to foamboard, but if I had your possibilities, I would try to start a new project from scratch using foamboard and hot glue. I don't want to take away your illusions or be too severe, I just want to avoid you damaging your electronics in an accident. And of course, that you will damage your desire to stay in this hobby.
I don't think the tape is going to hold the structure up under the force of flight. GEt some foamboard, hot glue and go for it again fallowing the plans carefully. U wont regreat. You won't regret it, and in a few months you may feel more confident about modifying your spitfire cardboard and giving it a second chance.
Once again, I'm not trying to make you feel bad, I just want you to go safely to the airfield and have a successful takeoff and landing.
