"Matt Whiting" wrote in message
...
Big John wrote:

Andrey

As has been said in all the posts, the short answer is NO. 172 is not
certified to do barrel rolls.

However I can barrel roll a 172 only pulling 1 G which puts no more
load on airframe than straight and level flight. I have thousands of
hours to back up my statement.

Your thousands of hours aside, this is simply an incorrect statement. A
barrel roll requires flying a loop and you can't fly a loop at 1 G. It
sounds like you are describing an aileron roll.

Matt

I think what John meant was that once you start the roll by blending in
aileron, you can "adjust" in pitch to any g you want. Naturally, in the
initial pull to the roll initiation point, (assuming a straight pull with a
rolloff into the barrel roll, you will be pulling more than +1g. A lot of
people have trouble visualizing this "split" between the roll entry and the
roll itself and naturally include the pulling g into the roll to arrive at a
higher g required to do a barrel roll.
The truth of it is, once that aileron is blended in and the airplane is
rolling through 3 dimensional space, you can actually unload it all the way
down to 0 g and improve the roll rate, which is exactly the way many fighter
pilots do these 3 dimensional rolls in an ACM environment. Some fighters
like the F100 and the F4 (at certain aoa and airspeeds) can be barreled (any
roll done in both the vertical and horizontal maneuvering planes using all
three dimensions is a barrel roll :-)) using rudder alone. It must be
assumed of course that positive g must be re-aquired on the back side during
the recovery back to level flight.
But make no mistake, you can play around quite a bit with the g during the
area of the roll between the two knife edges by playing the pitch you are
using during that phase of the roll :-))
I've done barrel rolls deep in the left side of the envelope using hard
inside rudder in high performance jets that you would swear were snap
rolls!! :-))
Dudley Henriques