The Influence of the Application of Power during Spin Recovery of Multiengine Airplanes Page: 4 of 8
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NACA TM 1219
III. PRFCRMANCE OF THE TESTS
All test flights were started at an altitude of 2000 meters. The
entry into the spin was effected by slowly moving the control stick rear-
ward until the airplane was almost stalled, then pulling the stick back __
to its limit followed with a simultaneous sudden rudder deflection to
obtain the desired spin direction. The rudder was kept in this position
until a recovery attempt was made. After a steady state with engines
idling had been attained, the throttles were opened wide - according to
the combination to be investigated - and the second steady state now
arising was awaited. As soon as the latter had set in, several turns
were measured. Recovery from spin was made by means of the expedient
described in Forschungsbericht Nr. 1100 of the DVL which will be indicated
here once more.
1. Sudden full rudder deflection opposed to the direction of
rotation; no pressing forward of the stick but yielding to the elevator
if it tends to move forward by itself; ailerons in mean position.
2. Immediately after the cessation of the spinning rotation all
control surfaces neutralized and a gentle pull-out of the ensuing nose
After the control surfaces were moved for recovery the turns for
recovery were measured to determine the influence of the propulsing unit
in each case. No measuring instruments were installed for this brief
investigation. In order to be able to determine the number of turns
required for recovery, the spin was made over a characteristic pattern
of lines (in the present case over the Oder river). The controls were
moved for recovery when the longitudinal axis of the airplane was parallel
to the direction of the line fixed relative to the ground. In this manner
it was possible to count continually from half-turn to half-turn and to
determine the recovery within an angle of approximately 200 with respect
to this direction. In order to determine the angular velocity of the
steady spin several turns were timed and the corresponding rate of descent
ascertained from the loss of altitude occurring during the timing. Of
course, this simple test method may be applied only when the pilot has
had extensive experience with spins.
With the engines idling the state of spin became steady between the
third and fourth turns. The rate of rotation and the rate of descent were
measured from the fourth to tenth turns and the recovery was started after
the eleventh turn. The spin was rather steep, the angle of attack being
approximately 300. The airflow at the tail was such that the elevator
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Höhler, P. The Influence of the Application of Power during Spin Recovery of Multiengine Airplanes, report, June 1949; (https://digital.library.unt.edu/ark:/67531/metadc64689/m1/4/: accessed April 25, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.