Winglets

On 12 Mar 2006 16:18:44 -0800, "Tony" wrote:

Most winglets I've seen point upward, but thinking about the physics of
the things, if they had to extend in only one direction wouldn't down
be better, and wouldn't a plate -- extending both up and down, be best
for sub sonic flight?


According to something I read somewhere :-) either up or down
winglets (or tiplets if you prefer) accomplilsh the same thing with
the same efficiency... increase the effective wingspan of the
aircraft. Most commercial aircraft (Boeing, Airbus, etc.) turn them
up for ground clearance.

Don't know about tip plates.

Ron

It seems to me tip plates would remove wing tip effects completely:
airflow would be along the chord all the way to the plate. I'd expect
the tip vortex effects one often sees would no longer exist.

"Tony" wrote in message
It seems to me tip plates would remove wing tip effects completely:
airflow would be along the chord all the way to the plate. I'd expect
the tip vortex effects one often sees would no longer exist.

The plate would have to big enough to block most of the tip flow in order to
be effective. That would be a fairly large tip plate and may have other
consequences such as directional stability. I used to tow banners in
modified Super Cibs with tip fences. The fences were about about 4 inches
bigger than the chord profile and did very little in reality.

D.

OP wrote:
On 12 Mar 2006 16:18:44 -0800, "Tony" wrote:


Most winglets I've seen point upward, but thinking about the physics of
the things, if they had to extend in only one direction wouldn't down
be better, and wouldn't a plate -- extending both up and down, be best
for sub sonic flight?



According to something I read somewhere :-) either up or down
winglets (or tiplets if you prefer) accomplilsh the same thing with
the same efficiency... increase the effective wingspan of the
aircraft. Most commercial aircraft (Boeing, Airbus, etc.) turn them
up for ground clearance.

Don't know about tip plates.

Ron

Airbus has plates that go both up and down at the end......
Michelle