REFLECTOR:Stall Characteristics

[Dave Black]

Richard,

> I read the NTSB report on that one, Neil Hunter's crash.  While it is
> likely (almost certain) that the wake turbulence put him inverted and
> stalled, it was also clear that he was flying aft CG, the weight he
> normally carried in the nose when flying solo was not in the airplane.

That is my understanding as well. 

The reason we concern ourselves with CG in aviation is primarily for stall
recovery. If you look at some of the early films of flying machines, you'll
see some interesting shapes that flew just fine -- right up until they
stalled. At that point, they simply 'fell out of the sky' in an uncontrolled condition.

Somewhere along the line it was discovered that if aircraft were a bit nose
heavy, they would fall nose first when stalled, and thereafter could fly out
of the stall in a controllable manner. 

I believe we all take this principle for granted in conventional aircraft. Why
should it be any different in canards?

In the case of Neil Hunter, wake turbulence precipitated the stall. But I do
not believe you should count that as the 'cause' of the crash. The crash was
caused by improper aft CG loading. Because of the aft CG, that particular
aircraft was destined to crash the first time it stalled. 

Bottom line: It's all about CG. Before we get all worked up about the stall
characteristics of canards, I believe we need to be careful to consider the CG
of the canard in question. If the plane is loaded aft CG, blame the pilot, not
the aircraft.

Dave Black