It’s a good thing that I scrolled the Comments,
because I otherwise would have started a whole
new Thread; attempting to say that the Post
is NOT at all a ROGALLO
Wing-but rather a Ram-Air Inflatable Parafoil….

The WING of a Rogallo is not inflated, it is defined
by a Central Keel-Spar & two Leading-Edge Spars, all
joined at the Nose & forming an “Arrowhead” in
Planform; the Spars supporting a Single-Surface
Fabric Covering which (when either supported
inverted, or when the device is airborne and right-
side-up…) outlines the form defined by the
intersection of the Spars overlaid onto a pair of
tapering or conical Cylinders, adjoining each other
along the line of the Keel…

Back in the early 1960s there were attempts by
NASA to use inflatable “Air-Booms” for the Spars of
a “Parachute-packable” Rogallo Wing, with which to
attempt to lower a Gemini Capsule and thus be able
to steer it, after Re-Entry…, but while the Air-Booms
were inflated with Compressed-Air, the Rogallo Wing
itself was not at all inflated, so much as it was
unpacked & spread-out.

By contrast if you suspend a Parafoil inverted,
held by the Harness at the Junction of it’s Shroud-
Lines, then it will hang in a loose clump of non-
aerodynamic folds of Fabric…, the only way to coax
a Parafoil to spread itself out & become a
functioning Aerofoil is to either anchor it to the
Ground in a strong wind, tow it behind a Vehicle
during a dead-calm, or to pull it out of a Bag
dragged from the top of the Canopy by a small
Drogue-Parachute, while attached to a Weight which
is falling from some considerable Altitude.

Thus, the “Apparent Wind” flows vertically up past
the Weight (usually a Skydiver) and therefore
spreads the Parafoil out in Planform, partially
inflating the “Cells” between it’s upper& lower
Surfaces, and adopting a “cambered” profile (French
word meaning “Curved”); whereupon it begins to
move forwards (due to a small Negative “Riggers
Angle-Of-Attack” which is imparted to the inflated
Aerofoil by the carefully pre-contrived lengths of all
the Shroud-Lines…, and both energised& oriented by
Gravity acting on the Plumb-Bob (Skydiver) which is
falling down to Earth perpendicularly underneath the
Parafoil.

Thus the inflated and and cambered Parafoil is
endowed with some amount of Forward Airspeed,
and it therefore generates Aerodynamic Lift, and it
then Glides downhill, enabling it to be controlled in
both Pitch & Yaw Axes (with very strong Roll-
Coupling, imparted by the Centrifugal-Force acting
on the suspended “Intelligent-Pendulum”, which
dangles under the Wing on a sculpture of String…)

But, truly Scotty, a Rogallo is NOT a Parafoil;and
calling a Parafoil a Rogallo is a terribly great
WRONGNESS, it’s at least as erroneous as calling a
“Zeppelin”- ie a fully Rigid-Framed Lighter-than-Air
Dirigible” Airship (another French Word, this one
meaning “Steerable”, a “Blimp”)

Blimp” being, of course, the abbreviation of
“Balloon – Limp”,technically denoting a Dirigible
Airship that has no internally rigid Structure & which
therefore maintains it’s streamlined shape by the
contained pressure of all the Lifting-Gas inside it’s
Envelope.., and, by common convention, Semi-Rigid
Airships which have a Keel inside their otherwise
unsupported Gas-Bag, are also termed “Blimps”.

All these different “Aeronautical” words exist for
good reasons, because they refer to DIFFERENT
Things, y’see.

You wouldn’t lightly tolerate it if anybody outside
your Field started publicly referring to Neutron Stars
as being Black Holes, on the grounds that they’re
both relatively small &dense…or if they refered to
you as being a “noted Astrologer” rather than an
Astronomer- because both get paid for being
Starstruck, and pondering and pontificating
endlessly with regard to what they claim to be the
hidden meanings behind all those tiny little Lights
which are apparent in the Sky at night…

So, pretty Pretty PLEASE, stop making a Public
Fool of yourself by calling a Parafoil a “Rogallo”;
simply alter the Title -correct your mistake,
delete the word “Rogallo” & replace it with “Parafoil”.

Otherwise, you are knowingly contributing to the
misinformation of all those of your Viewers who
wouldn’t otherwise know a Parachute from a
Parasol, and who thus look to you for inspiration &
education; and who trust that you do actually know what you’re talking about, and that you care
sufficiently as to painstakingly “get it right…”.

I realise that this may strike some people as being a
trifle pedantic & pernickety; but Science is ALL
about weeding-out the Bullshit, and you’re “forever”
banging-on about the alleged beneficial educational
effects of playing Kerbal, so please Retrofix what
you’ve fucked up in this Comment…

Just (ifiably) sayin,

Take it easy…