Humpty Bumps are simple family-8 figures to which a wide range of complementary rolls (including spins) may be added to create a great diversity of results.
The variations can go upwards or downwards from the start point, and be either vertical or skewed to commence with a 45° or 135° pull or push from horizontal flight. The turn-around is always a half positive or negative loop to reverse the aeroplane in pitch through 180° back towards the start point.
The same entry and exit radius and line rules apply as for a stall turn, the pull or push half-loop must also be of (not necessarily similar) constant radius, and the heading must be accurately maintained throughout.
In the main example here a 45° skewed Humpty has a two-point half roll on the up-line and a half positive flick roll on the down-line. The inset shows a 'plain' all-positive erect vertical humpty without added rolls.
In the diagram
- Radius 'A', 'E' and 'D' must be constant, but need not be the same
- Length 'B' = length 'C'
- Height difference 'F' is not important.
The entry and exit radii and the radius for the half-loop can be all of different sizes, but they must be smooth arcs - a tightening or widening of the radius after the initial pull or push should attract the usual 1 (minor), 2 (more noticeable) or 3 (severe) points downgrade. The standard 1 point/5° error applies for the two major lines, and during and after the turn-around where slow speed and high torque in up-going humpties can lead to significant heading variations and part-stalls.
Line lengths before and after up or down rolls are judged with the usual 1 point downgrade for a visible variation, 2 for a 2:1 variation etc.. Where a spin is imposed on the down-line of an 'inverted' Humpty it will of course be at the top of the line, and any subsequent roll before the pull or push turn-around executed after a brief pause - note that this second roll should NOT be centred in the remaining line, that is an error.