with a little creative ballancing and adjustment of control throws, my alpha 40 will do it (takes quite a bit of attention to what the plane is doing to keep it there though). it does lose some altitude, but it sustainable for a full pass more or less. you really have to stay in control of the roll axis to keep it there and quite a bit of elevator work is required to keep it straight as well. but i assure you it can be done. now on the other hand, my profile will do it till i can't see it anymore quite easily.