At this point a simple training aid may help;; use the centre cardboard tube from a bog-roll,or kitchen roll; highlight the `skewed join line` along the tube; from one end draw a little aircraft symbol in the `direction highlighted`.
Draw further symbols at each 90 deg position around the tube,and along it`s length....You should now have a `corkscrew` flightpath,for either a LH/RH barrel roll.
Henry Crun`s diagram is probably taken from AP129,and is incorrect,in that the symbols of the aircraft are 90 deg. out.
At position `D`(6 o`clock) the aircraft is at the lowest point in the roll,with wings level; at `A` the aircraft is at the wings vertical position and climbing at about 45-60 deg nose-up; at the position `B`the aircraft is wings level,inverted, nose above the horizon,just maintaining `positive G`,but still rolling,and then position `C` is 90deg wings vertical,and so on...
The critical point is at the top of the barrel,as noted by NoD,that the wings should be level,and the nose above the horizon; if not, you can end up in serious `crap`....
Now you can look at your `Blue Peter` aid and see where the heading and pitch attitude should be at any point around the barrel.
For an `outside view`,go to YU-TUBE,and search `tonneau barrique d`un Transall`.Another couple of videos,search for `piloted by Sobolev`....
I should add that depending on your aircraft type ,one can get away with about 2G pull at the start,and `float` over the top....(with practice !)
If you want to see `how not to do it, then search for `Biggin Hill Invader crash`...
Last edited by sycamore; 9th Jan 2011 at 11:52.