I've seen it happen on an ASW-24. The 24 was oriented
with the tail towards the southwest (northern hemisphere,
in North Carolina, USA). The canopy was fully open
and pointed towards the sun and we smelled plastic.
It was melting a portion of the trim around the glare
shield. We then moved the canopy up and down and watched
the bright white spot form on the glare shield when
the canopy was in the 'sweet spot.' It looked just
like it looks when using a magnifying glass out in
the sun when burning paper or ants.

Since my LS-1d has the removable canopy rather than
a hinged one, I guess I don't have to worry about it.
:-)

Ray Lovinggood
Carrboro, North Carolina, USA

At 13:54 04 May 2004, Jj Sinclair wrote:

I'd heard of this phenomenon before, but couldn't figure
out exactly how it happened.

I believe it occurs when the sun angle is parralel
with the top of the open
canopy and the magnification is caused by rays passing
through the plexiglass
at almost a zero angle. The fire is started on any
object that is close to the
focus point, ie. instrument panels, head rest on K-21
or DG-300. I know of an
ASH-25 that was *totaled* after a cockpit fire caused
by this phenomenon.
JJ Sinclair