Sounds like a pretty cool sort of project and I wish you the best of luck with it.

I think that will need something bigger than a weedeater engine. I would guess a conversion of some sort of small motorcycle or industrial engine would be more in order.

When you consider that the full size is only a 30 ft Span, uses 100hp and has an empty weight of 830 lbs - I'm guessing that your model is going to be needing in excess of 20 hp to get airborne with any hope of success in keeping it there.

Don't know about the covering.

I hope that your field is long and in a very clear area without people around.