Well, I certainly ignited a firestorm! Good. Getting people talking is a good thing.
Randy is right in one respect -- as builders of an airplane we are entitled to set whatever limits we want, as we are legally the manufacturer. I'm also pleased that his loyal passenger paints a picture of an otherwise very cautious pilot. I still won't fly with him, but then, it's hardly likely that an invitation would be forthcoming, eh?
However, as I tried to say before, there many factors which influence the selection of a never exceed speed. Sometimes it is flutter (that's a for-real, don't-screw-with-this limit, but does not appear to be the limiting factor on the 320/360 airframe), sometimes it is loading imposed by an FAA-specified gust (that's a somewhat artificial limit because there is no guarantee that you'll see that gust -- you might get more or you might get less), sometimes it is loading imposed by a fully deflected aileron at Vne (if that's the case then you might go faster safely if the controls are not fully deflected), sometimes it's a stability or controllability issue caused by Mach-induced center-of-pressure shift (not gonna happen on an LNC2, but it might on an LNC4). And those are just the more common reasons why a particular Vne speed might be chosen.
Certified airplane manufaturers have to prove to the FAA that the vehicle is safe in all respects up to Vne. Experimental aircraft are not subject to these constraints -- we can pull numbers from wherever we choose in order to set our placard limits. Myself, I have simply assumed that Lance and company used a methodology similar to that used by certified airplane manufacturers in establishing their placard limits. I suspect that they actually used the identical methods, but were not obligated to prove it with FAA-approved and DER-witnessed analyses and tests. No, I don't know that for sure. In that respect, no, I have not done any research to convince myself that the Lancair factory limits are safe, either. But Lancairs have not been breaking up in flight with any regularity (except in thunderstoms) so the established limits, which most pilots observe, are probably okay.
I think it is interesting that Randy and his loyal passenger have assumed that I don't know what I'm talking about simply because my Lancair is not yet flying. In fact, it is not complete because I was way too busy for several years as a professional aircraft designer, serving as Chief Engineer on an aircraft that was to be certified under FAR Part 23, and later teaching a class on designing aircraft so that they may become certified. And yes, conducting structural loading tests on wings, fuselages, and vertical tails. Aircraft engineering is what I do for a living -- building them in my garage is what I do for a hobby. But this is not a "mine is bigger than yours" contest, so I'll stop there.
Jeff Edwards has suggested that I prepare a posting fully explaining how Vne is determined. He said, and I agree, that many people reading this list would enjoy an educational posting of this nature. Someday I may do that, but it's not a short subject and I don't have time right now. Consider that a cop-out if you must.
Fly safe.
- Rob Wolf