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Aftermath: Three to Get Ready

Gemini Sparkle

Key Takeaways:

  • N72TZ, a unique homebuilt canard twin aircraft, crashed fatally on its first flight after an uncontrollable, extreme pitch-up.
  • While the NTSB attributed the accident to "the pilot's failure to maintain pitch control," the article explores a more probable technical cause.
  • The author theorizes the crash was likely due to severe longitudinal instability, stemming from an aft center of gravity (CG) that was dangerously misplaced for a canard-configured aircraft, especially after modifications to enlarge the canard and shift the CG aft.
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Considering how rare single-seat twins are outside the military, it’s remarkable how little information about N72TZ can be found on the Internet. The NTSB’s report on the fatal outcome of its first flight provides scant detail about the airplane itself. It seems, from bits and pieces mined here and there, to have been one of a kind, designed by a homebuilder, to have had a gross weight of 800 pounds and to have been powered by two two-stroke Hirth engines, each developing 28 hp at 6,500 rpm and driving fixed-pitch propellers, possibly through cog-belt speed-reduction systems.

Two photographs of N72TZ can be found, seemingly taken moments apart. It was a sleek, attractive airplane, painted a deep claret color, with sinuous lines — the sort of airplane amateur designers love to sketch. Its general arrangement resembled that of the three-surface Piaggio Avanti, with a T-tail, a small canard and pusher engines set inboard on the wings. Its ground attitude appears to have been a bit nose-low, like that of many jets. From its shadow — the sun stood more or less at the zenith when the photographs were taken — one can see that the areas of its three surfaces, relative to one another, were roughly similar to those of the Avanti. It was shorter-coupled, however, and the mainplane was located approximately amidships, whereas that of the Avanti is farther from the canard.

Peter Garrison

Peter Garrison taught himself to use a slide rule and tin snips, built an airplane in his backyard, and flew it to Japan. He began contributing to FLYING in 1968, and he continues to share his columns, ""Technicalities"" and ""Aftermath,"" with FLYING readers.

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