The Vampire could be a hard plane to build, trying to get that light cardboard glued down without warping the wing.  In our area we had several of them fail when the motor mount came loose on the dowel and burnt it enough from vibration that the plane came apart.

The Vampire was the result of two years of playing with foam construction and we have learned a lot since then. They flew good, but had to be built properly. If so they were tough. I built 6 that I used for 66, 67 and 68. Still had 5 and the 6th was repairable, but they were a long way from the next generation...... It just proved my old saying "you can't build a perfect kit unless you supply a builder in each box" so we did not keep it on the market very long.  I would have to say it was successful, if not profitable.  At 75 Nats Richard Wilkins wanted one of my Vampires so I traded for one of his planes, which I still have powered with a G21-15 ST.....It's great fun to fly but slows very bad in turns. 
RW

It just proved my old saying "you can't build a perfect kit unless you supply a builder in each box"

Heh.  That sparks memories of helping customers when I was working for my dad's company.  Roadster bodies have to be mounted on a straight and true frame if the doors are going to fit properly -- about 95% of our "your product is @#$%, the doors don't fit" calls ended up being because of a frame that was bent, twisted, diamond-shaped, or otherwise just plain wrong.