Additional studies of the stability and controllability of an unswept-wing vertically rising airplane model in hovering flight including studies of various tethered landing techniques Page: 15 of 27
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far -oritaly, w the tail corol w nt p t
or yaw the model wih the tail ixestain ed by the thing ine. It was
not posble in these cases to tilt the model so it would return to its
origlnal position This landing technique would become ltess> tnsats .
factory, however, if the tension in the line w.s reduced
El.ect of tethe$ring cable and hook.- e... swinging of a weight
hanging on a line attached near the center of gravity h.ad no appeciable
effect on the stability and controlla.bility of the model. This weight
was intended to represent a tetherlng hook and cable which would be
used to pull the airplane down for landings. The mass of the block
(which represented about a l -b hook on a 12,000 l- b airplane) was
evidently too low to affect appreciably the mot ions of the model'
The following results were obtained from hoveri ng flight tests of
an unswept-wing vertically rising airplane model with the a.nter-o-
gravity located at the leading edge of the wing:
1. The rate-gyro automatic stabilizing d tevi.ce which moved the
elevator to oppose pitching velocities improved the stability t-of the
uns table pitching oscilation of the model but did not make it stabl.
2. For comparable control size and deflections, the maneuverabilit y
of the model was greater with tail controls than with d..rect lift con
tro~ s on the wings but the mode could be flown more smoothly with wing
controls particularly when hovering near the ground.
3. The rolling motions of the model could be controlled fairly
smoothly and easily by means of ailerons on the inboard part of' the
wings despite the large fluctuations in propeller torque.
4. In gusty winds (average velocity of about 13 miles per hour for
the full-scale airplane) the model was more difficult to fly than in
still air and could not be held over a spot on the ground but sustained
flights were possible.
,. Satisfactory landings could be made by pulling the mod el hor
zontally into a saddle by means of a line attached near the center of
gravity of the model.
6. Landings in which the model was puled down by means of two
lines attached to its awing tips were the esies t to perform.
CO Nt I 15 NTIAL
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Bates, William R.; Lovell, Powell M., Jr. & Smith, Charles C., Jr. Additional studies of the stability and controllability of an unswept-wing vertically rising airplane model in hovering flight including studies of various tethered landing techniques, report, November 6, 1951; (digital.library.unt.edu/ark:/67531/metadc58981/m1/15/: accessed September 25, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.