You can download here an OpenRocket distribution that contains model rocket designs in ORK format. This distribution contain OpenRocket version 1.1.10pre, which is the version currently being developped and pottentially unstable. If you want a stable version of OpenRocket download it on the official OpenRocket web site.
The file needs to be uncompressed and contains several directories with model rocket design for each brands.
If you find conversion errors in the designs contact us with the contact form.