The Ultra Sport is MUCH less draggy than this plane. That is one of the reasons this plane performs so well. The 1.4 will fly it, but anything above Sportsman and it will be hurting. There is a difference in flying it, and flying it well.

Just my opinion after flying this plane for more than 2 years and putting more flights than anyone on this design. I have flown them with a 1.60DZ and have flown others with OS 1.60's on them. That is the minimum I would put on this plane,

Arch