ABANDONED. Fantasy book about wind powered machines

[Caleb]

I remember reading a book as a kid (book probably came out 90s early 2000s) that involved nations going to war with machines. Since the book was set in some vague middle ages time, there were no robots. Instead, the machines were powered by the wind, and carefully steered by people onboard.
The main character managed to callibrate the machines to work without a pilot, meaning nobody was hurt on their side. Interestingly, the other side took a calibrated machine and copied the technique, leading to a war with no casualties.
In the end, the machines were abandoned due to other, more disturbing military techniques being developed.

[Kris]

Caleb, please post a new comment if you're still looking for this book - or if you found it.

Caleb (OP) was last active on the site in December 2019. Moving to Abandoned folder.