Once in awhile, jumbo jets fly over my house on their way to Paine Field. Even though they are flying over 500 mph, they look like they are doing about 50.
Same holds true with huge models.
Why invest so much time and money into stuff that looks slow unless it's actually doing 200...?
It's like beating your head against a wall.
Those Balsa USA deltas are "dogs" [a waste of time] if you are really interested in going fast.
With the same power you can go as fast or faster with a Tower Hobbies trainer.