We had a lengthy debate at the recent OCMA contest regarding the F-17 Barrel Roll.

The debate centered around whether or not the rolling portion of the maneuver was to be performed around a horizontal line or on an upward 45 degree line. I interpreted the descriptions and the powerpoint to show that the plane pulls to a 45 and begins to roll. The roll is around a horizontal line and the plane ends up at the same altitude at which it started.

The opposing view was that it pulls to a 45 and stays on a 45 upward line as it rolls.

According to Michael Ramel (I pulled this from the F3A Germany Facebook page), my interpretation is correct. I am curious as to what the rest of the world thinks the orientation of the roll to be:

Clarification for F-17.07 "Barrel Roll" by Michael Ramel:
"At first, please recall the manoeuvre description as in the Sporting Code:
F-17.07 Barrel-Roll
From upright, pull through a 1/8 loop into a 45° upline, perform a barrel-roll with 45° spiral pitch, perform a 45° upline, push through a 1/8 loop, exit upright.
You first pull into a 45° upline, then at mid level you start to perform a full roll with the flight path going around a horizontal cylinder in a spiral (as the thread of a screw in a 45° pitch).
Assumed you fly from right to left performing the barrel roll into right direction:
From low level, the aircraft pulls upright in a 45° upline first, then will be in a knife-edge (right wing down) position after the first 1/4 of the roll heading away from you in a 45° angle seen from above, then it is inverted on a 45° downline after the second 1/4 of the roll, then in a knife-edge position (right wing up) after the third 1/4 of the roll heading towards you in a 45° angle seen from above, finally it is upright again in a 45° upline after the fourth 1/4 of the roll as to finish the manoeuvre on high level.
You have seen this barrel roll many times in show flight performances when ie. one aircraft is flying on a level line, while another aircraft spirals around it in one or more barrel rolls. However, for F3A this manoeuvre is precisely described and brakes down to the various geometric reference points."










I hope we interpret it the way the rest of the world interprets it.

I was always under the assumption a barrel roll was a positive G maneuver. Aileron and elevator applied at the same time to complete the maneuver. Entry height and exit height should be the same. There should not be a 45 degree upline before the start of the maneuver or at the end. I double checked myself at the IAC website. This is what they have to say.

"The Barrel roll is a combination between a loop and a roll. You complete one loop while completing one roll at the same time. The flight path during a barrel roll has the shape of a horizontal cork screw. Imagine a big barrel, with the airplanes wheels rolling along the inside of the barrel in a cork screw path. During a barrel roll, the pilot always experiences positive Gs. The maximum is about 2.5 to 3 G. The minimum about 0.5 G." https://www.iac.org/legacy/aerobatic-figures#BarrelRolls
This photo has always been my conception of a barrel roll.

I found this explanation here. file:///home/chronos/u-602a21254c188237162d19257f2dfec286b0e8fe/Downloads/SC4_Vol_F3_Aerobatics_14_Rev_1%20(1).pdf

F-17.07 Barrel-Roll From upright, pull through a 1/8 loop into a 45° upline, perform a barrel-roll with 45° spiral pitch, perform a45° upline, push through a 1/8 loop, exit upright.

I "think" they are trying to explain a classic barrel roll with technical term. Somehow it just doesn't translate.

With the above said I am not an accomplished aerobatic pilot. I do, do a pretty good job of faking it though

Ken

Steve,
I agree with your interpretation (and Mr. Ramel's clarification). The part of the maneuver description that convinces me is this: "perform a barrel-roll with 45° spiral pitch, perform a 45° upline,"; after the barrel role you are then to perform another upline. This tells me that the airplane was no longer on the initial 45 upline and had returned to level flight. The maneuver description should be changed to: "perform a horizontal barrel-roll with a 45 degree spiral pitch" .
Just my 2 cents...

I think a significant part of the 45 upline before is for altitude control. Otherwise, you would be diving during a bottom of the box maneuver, so putting it on a 45 upline helps keep the bottom no lower than the start altitude.

Arch

Now let me get this straight (and I'm looking at the aresti drawing). You start from level and pitch up 45 degrees, wings still parallel to the ground. Somehow, when you pass the level of the horizontal line defining your barrel axis your plane must be in a 45 degree climbing knife edge. Then you fly a 45 degree corkscrew around the barrel ending at the level of the barrel axis in 45 degree climbing knife and also magically now with wings parallel to to the ground in a 45 degree climb.

It looks best done negative like they do indoor for F3P.. Pull up 45 then down elevator and rudder like and outside snap.. You finish the barrel roll on a 45 up like..
its a **** of a thing to make look nice but gets easier to more you do..

I vote, just remove it, LOL... To many variations on how to judge it.

Bill

The few barrel rolls I've done in the past I've applied up elevator and aileron at the same time. Controlling the amount of input will vary the pitch/roll. Get it just right and the "upline" on the first 1/4 of the maneuver will be 45 degrees. You also be in "knife edge" though because the roll is a positive G maneuver no rudder is used.

Ken

Ken, Your description follows the maneuver most of us are familiar with, which has an entry at the bottom. The subject of the debate is FAI's description in F-17 that adds a 45 degree entry and exit and appears to enter the actual rolling part from the side. Typically garbled FAI maneuver description that will take two years to determine what they want in Europe. Reviewing shannah's original post, this sounds like a knife-edge barrel roll and not a positive G maneuver at all.

You are correct. I need to read and UNDERSTAND what I am reading. Still the description is not clear and IMO leaves much to interpretation. Ken

Correct. It's neither positive or negative really. The wing tip follows the "barrel" around, not the top or bottom of the plane as a normal barrel roll is performed.

If they used the description as per Michael Ramels clarification, there wouldn't be so much confusion.