For some reason, I can't get this to work. I've downloaded the most recent version of the protractor, and unzipped the folders into my KSP folder. However, the parts in the VAB are grayed out, and a note in the description says they're not available in my version of KSP. I've deleted my entire KSP folder, re-downloaded, and tried again with the same result. I feel a bit like a dope, but I've run out of ideas.