Velocity stall???
Russell Kent
> Can a Velocity stall? I watched their video and they said NO! However, I
> heard of a test pilot in Canada who died during a test flight from a stall.
The answer is: it depends.
I assume you already know *why* stalling the main wing of a canard aircraft is
a Very Bad Thing.
In general, canard aircraft are designed so that the canard stalls before the
main wing. This can be done by have the canard mounted at a higher angle of
incidence than the main wing or by using different airfoils for the canard and
the main wing. By having the canard stall first, the nose drops which in turn
lowers the angle of attack of the main wing, which keeps the main wing from
stalling.
Murphy's Law being what it is, however, there are occasions where the main wing
can stall:
1. Improperly constructed airfoil on either the canard, the main wing, or
both
2. Improperly attached airfoil causing an incorrect angle of incindence for
either the canard, the main wing, or both
3. Contamination of the surface of the main wing airfoil causing early
turbulent separation of the airflow
4. Extreme control movement in a high-rotational-inertia or extreme aft CG
aircraft
5. Wind shear
Since you said "test flight", I suspect that one of the first 2 items might
have been the factor. The 3rd item generally points to a bad airfoil choice,
which is a design issue. The 4th item is a design or weight&balance issue.
The last item is just plain dumb luck.
Russell Kent
DAlexan424
>From: "Kemo" kmo...@yahoo.com
>Date: 5/19/00 2:13 PM Pacific Daylight Time
>Message-id: <q8iV4.62735$k5.16...@news1.frmt1.sfba.home.com>
>
>Can a Velocity stall? I watched their video and they said NO! However, I
>heard of a test pilot in Canada who died during a test flight from a stall.
>
>
>
That's a lot like saying the Apollo space craft was a piece of shit because the
first one burned up.
That was done probably 10 years ago on the first design wing. What first design
wings are still around have been modified to include a leading edge cuff on the
outer 1/3 of the wing. Newer wings have thicker chord and if you really want a
safe wing, look into the 173. It is a slower wing but developes much more lift
at slower speeds. Recent Velocities have suffered from fuel system problem from
owners not changing out the filters soon enough after first few flights and
thrown prop blades from those who insist on using IVO props, but over-all
safety hasn't been an issue with Velocities.
Dale Alexander
Velocity 173 RG Elite
Peter Chapman
>Can a Velocity stall? I watched their video and they said NO! However, I
>heard of a test pilot in Canada who died during a test flight from a stall.
There were a couple deep stall incidents early in the aircraft's life.
Extensive testing was done into the problem and fixes introduced -- I
think leading edge cuffs and later a redesigned wing with vortilons.
An article in Sport Aviation some years back looked at the testing
done.
The Canadian accident report concluded: "The pilot [...] lost control
of the aircraft when it entered a deep stall at low altitude.
Contributing to the in-flight loss of control was the operation of the
aircraft in a high alpha flight regime, the manual adjustment of the
canard before the flight, and the absence of vortilons on the wings."
It had looked as if the pilot had deliberately tried to do an
aerobatic maneuver, based on his behaviour on a previous flight, and
the pilot's extensive aerobatic experience.
The canard's trailing edge had been adjusted upwards, which
would reduce the canard's "protection" of the main wing from stalling.
The builder of the aircraft (who was not the pilot here) had
also not installed the vortilons, an omission which also increased the
chance of a main wing stall.
That's the thing about homebuilt accidents -- without a lot of detail
one can't know whether an aircraft failure was because of the design,
the builder, or the way the plane was used.
Peter Chapman
Toronto, Ontario
Dave
properly, the canard will stall, causing the nose to drop before the main wing
stalls, which lowers the AOA...yadda yadda...so the design is stall resistant.
But, there are cases of canards stalling the main wing for the aforementioned
reasons.