"Dave Stadt" wrote in message:
"Ace Pilot" wrote in message:
With the introduction of sport aircraft, many of which fly at approach
speeds well below 55 knots,

Don't know where you pulled this from but most sport aircraft will perform
equal to or better than most current light singles.

Depends on your definition of "perform."

Sport aircraft are not ultralights.

True. But all ultralights (including most "fat" ultralights) can be
certified under the proposed sport aircraft rule. In fact, this is one
of the basic reasons for the proposed rule – to better regulate
ultralights, especially those with two seats.

Current airplanes that qualify as sport aircraft such as J3s,
Champs, etc. fit in the pattern just fine and have been for 60 years or
more.

True. However, J3s and Champs represent the higher end of sport
aircraft. You are completely ignoring powered parachutes, trikes and
lower performance aircraft that are most likely to be sport aircraft
(because of their lower cost) and have significantly lower approach
speeds (typically 20% to 40% lower than a Cub).

One option would be to have them
use the same pattern every other single-engine aircraft uses (but
perhaps at a lower altitude?). However, this will just increase the
speed differential encountered in the pattern, perhaps as high as a
factor of three or four.

Huh? Three or four? Where did you get these numbers?

Many powered parachutes operate around 25 knots. Put one of those in
the pattern with an aircraft with a 100-knot approach speed and you
have a four factor difference. That's the extreme case. A sampling of
other aircraft with low approach speeds (source - manufacturer's web
pages):

Quicksilver Sport 2S – 40 knots
Quicksilver MX Sprint – 34 knots
Airborne Redback trike – 31 knots

It seems reasonable to me that the lower cost of these aircraft will
increase their presence at airports (either privately owned, or more
likely, flight school owned).

What's the best way to reduce traffic pattern risk when there is a
wide range in approach speeds -

1st Hint..........keep your eyes open!! Second hint......refer to first
hint.

Since sport aircraft are not required to have radios (nor are sport
pilots required to be trained in their use), see and avoid will be an
integral component for safe sport aviation activity. However, it's
been well documented that see and avoid is not fail safe. Its
effectiveness is limited, but by having standardized traffic patterns,
that effectiveness can be enhanced. I'm asking whether changes to the
current traffic patterns, in light of expected future activity, might
enhance the see and avoid system even further.