"From the very start, Pete Bowers intended the Fly Baby to be able to be built as a low-wing monoplane, a biplane, or a parasol. No work was ever done on the parasol (nobody expressed an interest) but about eight years after introducing the Fly Baby, Pete came out with the biplane wing plans.
The biplane mod adds a couple of hard-points on the stock fuselage for the forward attachment of the cabane struts and for the flying wire attachment. The two monoplane wings (120 sq.ft, 11.15 sq.m total) are replaced by four smaller panels and a top-wing center section (150 sq.ft, 13.94 sq.m total). Once the fuselage has been modified, a Fly Baby can be switched from monoplane to biplane (or vice versa) in about an hour (with two people). As far as the FAA is concerned, only a single log entry has to be made when the wings are swapped.
The biplane version is mostly cosmetic. The plane takes off a bit quicker, climbs a tiny bit better, but cruises slower and doesn't glide as well (due to the increased drag). Some people just like biplanes better. However, there are only 12 Fly Baby 1B models (the biplane) on the FAA registry (out of about 314 listings.)"
Visit Ron Wanttaja's Unofficial Fly Baby Page.