DG Flugzeugbau DG 202, Flight Manual

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Manual Compass 46--MFK--1 BOHLI MAGNETTECHNIK AG
Edition 01.2007 Page 9 of 16
If the indication of best climb occurs later after a shifting step, this is an indication that roll--out
has been initiated too early as shown by
▲
in figure 9. On the other hand, if the relevant hea-
ding for best climb is encountered earlier after every step, then roll--out was initiated too late
■ . Based on these observations an additional correction angle g or d may be introduced,
where g is added to 180 ° and d is substracted. The rough amount of these angles is easily
determined by each pilot for his personal style, plane and instruments.
If, after the short straight flight, we want to quickly come back to the same bank as before (and
thus the same radius of turn), we merely have to watch the mirror image of the E--W axis and
get it aligned with the horizon. In clouds, the same bank is confirmed when the red mark tra-
vels on a concentrical circle around the center of dial.
The aim of the Bohli inclination compass is purposely not an extremely high accuracy for rea-
ding headings. The instrument has been conceived, in the first place, to furnish information
fast; information which is not blurred or distorted by movements or accelerations. It also does
away with the complicated rules (lacking precise information) governing the interpretation of
declination compasses.
This instrument certainly also offers advantages in power and helicopter aviation, provided
the operating area is within the defined latitudes.
Literature
1) Balmer Heinz Beiträge zur Geschichte der Erkenntnis des Erdmagnetismus
(Sauerländer Verlag Aarau)
2) Hine Alfred Magnetic Compasses and Magnetometers
(Adam Hilger Ltd., London)
3) Fischer Arno Flugzeuginstrumente
(Hans Reich Verlag, München)
4) Simon Harro Instrumentenkunde und Navigation
(Hans Reich Verlag, München)
5) Nietlispach Hans Segelflug
(Fritz Marti, Buchbinderei, Bern)
6) Löwe Karl F. Flugzeugortung
(CJ. E. Volckmann, Berlin, 1934)