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Flight Test Log 6

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Summary
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Tests of new landing skid, subscale. Skid resized and reshaped to reduce
weight, aerodynamic drag and ground friction.



Also, the elevons reprogrammed to boost roll sensitivity. Control and
performance is acceptable with and without PAD attached.

However, more down elevator control is desired. Otherwise it can be difficult
to keep the nose down when the angle of attack gets too high. This may be
related to the high alpha mode.

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   Test ID:  18
      Date:  2005/03/12 (Sat)
      Time:  09:00
      Wind:  Calm
   Vehicle:  SVC
     Scale:  41 %
  Location:  Globe

Objective was to test new landing skid. Skid was modified slightly by
rounding off the nose in order to prevent digging in upon touchdown,
which had been a problem in test 16 (7 Mar).

Flew OK except that roll control seemed a bit sluggish.

Tried high-alpha mode too close to the ground. Attempted recovery resulted
in a hard landing, which broke the propeller and bent the propeller shaft.
The skid was cracked, and there was also a small crack in the styrofoam near
the motor mount. Otherwise there was no apparent damage to the airframe.



Damage to powerplant

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Modifications to subscale SVC:

[1] Reprogrammed elevons to increase aileron sensitivity and decrease
    elevator sensitivity:

    Old values:

        Elevator:  100 %
         Aileron:  50 %

    New values:

        Elevator:  75 %
         Aileron:  75 %

[2] The landing skid was reshaped to decrease drag. The LE was rounded, TE
    was tapered. New shape is closer to a teardrop.

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   Test ID:  19
      Date:  2005/03/13 (Sun)
      Time:  07:20
      Wind:  Calm
   Vehicle:  SVC
     Scale:  41 %
  Location:  Globe

Aileron sensitivity was better. Roll control was acceptable but more
sluggish than I would like, and adverse yaw was also noticeable (note that
the design has no rudder control). Climb rate OK, elevator control OK,
landing good.

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   Test ID:  20
      Date:  2005/03/13 (Sun)
      Time:  07:55
      Wind:  Calm
   Vehicle:  SVC/PAD
     Scale:  41 %
  Location:  Globe

PAD was attached. Control was OK but climb rate was inadequate, unable
to gain altitude. Hard landing resulted in minor damage to airframe.

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Modifications to subscale SVC:

[1] Motor replaced with unit used in earlier tests.

[2] Propeller replaced with new unit.

[3] Landing skid reshaped and shortened, new height = 38 mm, had been 61 mm
    max. Purpose is to reduce weight and drag.

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   Test ID:  21
      Date:  2005/03/15 (Tue)
      Time:  07:00
      Wind:  Calm
   Vehicle:  SVC/PAD
     Scale:  41 %
      Mass:  236 g
  Location:  Globe

PAD was installed. Initial climb rate was better this time, but after a
minute or two I noticed it was difficult to maintain altitude, probably
because of battery depletion. Control was OK, landing OK.

The skid modification probably fixed the climb rate problem.

Note that the motor on the subscale SVC is a relatively low-efficiency
brushed ferrite motor. The full scale SVC has a higher-efficiency Hacker
C50 brushless motor.

At one point, I had trouble keeping the nose down when the angle of attack
got too high. We should probably add more down elevator. This may be
related to the high-alpha mode.

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   Test ID:  22
      Date:  2005/03/15 (Tue)
      Time:  07:05
      Wind:  Calm
   Vehicle:  SVC
     Scale:  41 %
      Mass:  224 g
  Location:  Globe

PAD was removed. Battery charge is that remaining from flight 21 (i.e.
battery not charged between flights).

Climb rate OK, control OK, landing OK. Roll control is still a bit sluggish,
and adverse yaw is still noticeable, but overall control is acceptable.

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Last updated 2005/03/23 FLM