|Take-off with this rear center of gravity, also lower position
because of the bomb, can be performed without difficulty with normal
rudder position. Characteristics that go beyond the ability of an
average pilot do not occur.
Compared to the usual center of gravity, the stabilizer was 0.5° more
nose-heavy, adjusted to + 2.5° based on the geometric O position of
the horizontal stabilizer.
The aircraft is unstable at all speeds with a full tank and
consequently very sensitive on the lateral axis, so that it can not be
flown stick free.
The sensitivity to disturbances about the lateral axis decreases with
decreasing ram pressure.
Trimmed for climb, horizontal stabilizer trim = 3°, the existing
instability is hardly noticeable in reasonably calm weather, only
relative major disturbances or larger elevator deflections cause
Horizontal cruising flight, trim = +2.3 °, is possible without
significant difficulties at longest range speeds.
The present instability at high speeds is very objectionable,
noticable above about 400 km/h; especially in turns and in pull-outs
The high sensitivity of the lateral axis at small control deflections
is disturbing as well.
In turning flight elevator force reversal occurs, the aircraft
stalls on its own if no action is taken. Only after consumption of 200 l from
the rear fuel tank, the aircraft shows neutral behavior (with auxiliary
tank still full).
In summary it can be said that the examined rearward center of
gravity, except while flying blind, may still be permitted if
1. Immediate consumption of the auxiliary fuel from the installed auxiliary
tank is provided, if 2. in case 1) is not possible (GM 1 or methanol in
the auxiliary tank), care is taken that the conditions for an undisturbed
approach with 200 l of fuel consumed from the rear tank are given.
The center of gravity of 0.77 m - 0.72 m is unacceptable during enemy contact and the resulting defensive maneuvers.