7zip isn't for mac.
For some odd reason the Davepack will not install correctly on mac. So what you need to do, is go to "Other" and click "Open data folder". Navigate to the folder "Aircraft" and drag and drop the Davepack folder into there.
As for bombable, you need to download that, and install it using this pdf I threw together a while back for mac users:http://alpha-jsfilestorage.yolasite.com ... RST!!!.pdf
Let me know if you need further support.