"Maxwell" wrote in
:


"Dudley Henriques" wrote in message
news:2007061101084716807-dhenriques@rcncom...

Bertie is correct. Barrel Rolls are perhaps the most misquoted and
misunderstood maneuver done in an airplane.
Basically, you can do a barrel roll as loosely or as tight as the
airplane's flight envelope will allow. You can also enter a BR from
many different flight conditions involving many different g loadings.
The main thing to remember about barrel rolls is that they are a 3
dimensional maneuver through 3 dimensional space and that the common
denominator in a barrel roll regardless of the g used is that it will
remain POSITIVE all the way around. The one exception to this would
be after the pull and roll application, you can unload the airplane
over the top and drop the g to +1 if you like to loosen the roll
rate, but that g must be regained during the recovery.
Basically, you will be somewhere over +1g in the entry as you raise
the nose, then at some positive +g throughout the roll ranging from
as unloaded as you want to loosen up the airplane or as high a
positive g and tight a roll as the envelope will allow. As long as
the airplane transverses 3 dimensions through the roll, it's a barrel
roll. I've done them as loose as a 90 degree change of direction at
the top apex in a P51,the F8F, and several jets including the T38,
and as tight as a corkscrew in a Pitts S1Sl which was highly loaded
with +g and extremely tight.
Bob Hoover's rather famous Iced tea stunt in the Shrike is probably
responsible for much of the misconception about barrel rolls. He does
them fairly loose and with just enough positive g on the airplane to
keep the glass from spilling without stressing the airplane. The
"secret" to Bob's tea trick is simply his smoothness through the roll
as much as keeping positive g on the tea. It's really this smoothness
that makes this stunt possible, as although positive g will keep the
tea inside the glass. (You can actually POUR tea as you're rolling
the airplane but ONLY if you're as smooth as Hoover :-)
The reason smoothness is so necessary for the tea trick is that even
though you might have positive g on the airplane and in effect doing
a barrel roll, if you are not perfectly coordinated through the roll
(any excessive yaw for example) your tea will slide off the glare
shield laterally and you don't want that......not if you're Bob
Hoover anyway :-) So it's positive g for the roll, and smoothness and
perfect coordination for the tea stunt.

I'm not talking about Bob's tea trick. Obvoiusly, positive Gs and
coordination is the key there. And I'm not sure I understand or agree
with your post. But I think it might be possible we having a
terminology issue here with the definition of a barrel roll.

Nope. The thing is, you can`t do anything at all at one G except
straight and level flight.

Period, Endo fo story, finnito spaghettio. Nothing to do with
terminology or anything else. It's just a BS legend that has been
repeated so many times that it's dug it's own groove in the urban legend
record.



Bertie