Lynn,

 

Perhaps the other racers should consider a modification.  As it was explained to me, the oval strong shape of the tail cone is not continuous once the vertical strake starts to rise up from it.  That is, the structure is not continuously round back to the major structural bulkhead that fills the tail cone and extends upward into the forward part of the vertical stabilizer while connected to the carry through of the leading edge of the horizontal stab.  Try to visualize the resistant strength of a tube when one tries to twist it.  Now visualize if it were is constructed like the tail in the area of the strake - the tube is discontinuous there.   Such weakness can allow the tail to more easily twist between the start of the strake and the bulkhead.  This form of construction is at least true for 200/300 and Legacy series aircraft. 

 

One way to address this potential problem for 300 series aircraft is to complete the oval tail cone from the strake back to the bulkhead by floxing a fitted foam filler into the strake and then applying ample BIDs of glass (or carbon) across the filler and connecting the sides of the top of the tail cone.  Remember also that the vertical is bonded to the tail in a way such that this area is not strengthened by foam separating the inner and outer skins to begin with (monocoque concept).  I have seen cracks in the clear cost on the strake at its leading edge seam (no joggle there).  Others have seen horizontal cracks in the vertical part of the strake on their 360.  Of course, these Lancairs have been stressed - perhaps more than the average.

 

I am sure that the external application of carbon BID provides more strength.  If I were building today, I would fill the strake by floxing in proper strong foam while only half the vertical was constructed and bond the other half when the vertical was closed out.

 

Again, this is probably not worth considering for most Lancairs extant and flown within the design envelope.  One should consider examining the strake area carefully during each annual condition inspection.

 

 
  "Remember  that if you bought a carbon Legacy kit and intended to race it
at Reno, Lancair
  applied extra carbon in the tail cone and vertical stablizer area for
strength  and
  stiffness." 
 

The above statement in interesting. My Super Legacy was the first to have
the area from the windows to 3/4 the way up the vertical stabilizer
reinforced with 4 layers of additional carbon fiber. Darryl Greeamyer's
Legacy was the second.

My understanding is that, for an additional cost, a person can now order
this reinforcement incorporated in the kit when it is produced in the
Philippines.

I thought that with the higher speeds that were being flown at Reno that it
might be prudent to strengthen that area of the fuselage. I expressed my
concern to Andy Chiavetta. He, in turn, ask Greg Cole and Greg was greatly
if favor of the idea. Darryl, at first, resisted the idea, then decided to
do it too.

My highest indicated air speed, to date, is 340 knots. Greg says we are good
to .6 mach.

I don't think that any of the standard Legacys that race at Reno have this
modification.