Cheetah 160
Owner’s Manual
VB. (VARIABLE BILLOW)
The variable billow (VB. sometimes called variable geometry VG.) is used to change the flying
characteristics of the glider while in flight.
As mentioned else where in this hand book, when the glider is rigged the VB. cord should be threaded
through the cleat on the speed bar and knotted. (This is a good habit to get into. The knot will prevent the
end of the VB. cord being lost.)
If anything is attached to the right hand upright (the one down which the VB. cord runs) it could adversely
effect the operation of the VB. (See 'trouble shooting'.)
For take off it is recommended that the VB. is in the fully released position. (This is with very little cord
sticking from the upright.) In this position the glider is easiest to turn. (You may find with experience, and
especially if aero-towing, that you prefer to take off with a little VB. pulled on.)
In normal flight flying with the VB. fully released is easiest. A little VB. (Say 70cm of cord) might be
pulled on in smooth conditions. This will give a better sink rate with little loss of handling.
For flying fast or for best glide performance (for example, flying between thermals) use more VB. With
full VB. be aware that the roll rate of the glider is significantly reduced especially if flying slowly.
Do not
use full VB.
near the ground, near other aircraft or near any other obstacle.
For flying slowly, near the ground, near other aircraft or other obstacles, in rough air or landing it is
recommended that the VB. is in the fully released position. This position will give the most effective roll
control.
Release the VB. in a smooth manner. Do not just pull the rope out of the cleat and let go. This will give a
needless shock loading to the airframe.
VB. MAINTENANCE
Due to the design of the Cheetah VB., its operation should be smooth easy to operate.
To keep it this way, make sure that the ropes are clean and not twisted. Remove grit or dirt from the
upright casting and replace the ropes if they show signs of wear. It is also important to keep the tension
strop of the glider untwisted.
Silicon spray is a useful lubricant which will help maintain easy operation of the VB. Spray it both on the
keel in the area of movement of the leveller and its webbing loops and on the VB. pulley in the lower
upright casting.
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