Why can't I Redirect https:// to http:// Without Having an SSL certificate installed
Unfortunately this cannot be done due to the way that SSL works. When you open up the website in a browser, it sends a secure handshake request. This comes before the website content / Apache directives / .htaccess redirects come in place.
Practically an attempted connection over https:// will always display a security error if there is no SSL for the domain. It's a security measure so that connections over SSL will be established only after the validity of the SSLs has been proven on both ends.
Such a redirection can be done only client-side, however it isn't viable to expect end-users to take such action.