A quick followup: I just got this link through Facebook (Henry Mustin's development of the lighter idea):
National Naval Aviation Museum - Online Exhibits
The pictures, unfortunately, only show the N-9 tests. The Navy also ran tests with a Caproni bomber. Apparently those went well, except that the hold-downs wouldn't release properly. I guess there was neither time, money, nor interest to redesign and try again. But I have seen pictures of the Caproni on one of these!
-Larry