Quote Originally Posted by flyingriki View Post
Tell that to the guy that pioneered many of the designs and then built an operational spaceship......
...and the engineering department that backed him on most of the follow-on designs. Rutan wasn't exactly your average homebuilt designer. He has an engineering degree (graduated at the top of his class too) so I'd guess he knows how to actually do the calculations for this sort of stuff rather than just sandbagging a design to failure to get a rough estimate.

Then again Wanttobe is painting composites with a fairly broad stroke and it's a very nuanced field.