The Ovation bowl-back wasn't intentionally designed after the bowl-back mandolins, etc. Ovation's got a really interesting (well, to me...) history. Charlie Kaman was an excellent guitarist as well as an engineer. I remember reading an interveiw where he talked at length about guitars. He had an offer to go on the road with major band (not The Dorsey Bros., but someone of that stature, I don't recall who). But he turned them down because he was so close to finishing his degree in engineering. He wound up working for Sikorski, and moved on to start his own company after he was told "We don't need any new innovations, we've already got Igor Sikorski here". One of the problems he was working on was how to dampen the vibrations in the rotor blades while keeping the weight down. That's what they used the fiberglass for.
Meantime, he's still a guitarist, just loves the instrument. Being an engineer he decided to see how to shape the back of the guitar to best focus the sound, and that's the parabolic shape they came up with. It's engineered to really focus things together and eliminate canceled frequencies. He made a prototype with a wood back, but at the time he'd have to retail it at $1000. That was when the MSRP on a Martin D-45 was like $500, so he figured there wasn't a chance of selling it. While he and one of his engineers were talking about different ways to do it, someone else who wasn't a musician said "why not use that glass we wrap the rotor blades in?" Charlie and the other guy (who I think was a violinist) said "You can't make a guitar out of fiberglass!" but the third person said "Why not? You're trying control vibrations which is exactly what we do here in our rotor research."
So they built some of them, and sold one to Josh White, and then got a chance to get one to Glen Campbell. Campbell was just starting to be known outside of the studio scene and his manager started talking about needing royalties, etc. etc. Glen looked at the manager and said "Pay the man. I want THIS guitar.". At the time I got out of retail, Glen Campbell was the only endorser who ever got a free guitar from Ovation*. It was a gift from Charlie for Glen's undying support for 20 years or more.
John
*When I was a dealer, Ovation's endorsement deal was that every endorser got to buy two guitars a year at dealer net cost. The real benefit was great support. If an artist on tour had a problem with an Ovation, they merely contacted Ovation. Then Kaman Corp. would contact dealers in the area to get the artists something that was the same or very similar to their guitar. Then Ovation would arrange for the dealer to get the guitar to the artist, pick up the artist's problem guitar, and return it to Ovation. Meantime, Ovation would send a replacement out to restock the dealer, and give them some money for the work. That way the artist only had one phone call to make, the dealer got taken care of by Ovation, and every one was happy.
jte