Avian CHEETAH 160 User manual

CHEETAH 160
Owner's Manual
BHPA certificate of airworthiness
numbersCheetah 160 Race Mylar / Matrix):
0106161
Serial Number
......................
Before flying your glider please read this manual completely, check all your battens
against the batten profile (adjusting them if necessary) and do a thorough pre-flight
check.
AVIA LTD.

Cheetah 160 Owner’s Manual
Stretfield
Bradwell
Hope Valley
S33 9JT
UK
Tel [phone]
Fax [phone]
E-mail [email protected]
www.hanggliding.co.uk
CONTENTS
INTRODUCTION.........................................................................3
PLEASE NOTE............................................................................3
OPERATING LIMITS..................................................................4
SPECIFICATIONS.......................................................................4
RIGGING THE CHEETAH..........................................................5
PRE-FLIGHT CHECKLIST.........................................................8
FLYING THE CHEETAH ..........................................................10
POST FLIGHT INSPECTION......................................................11
DE-RIGGING...............................................................................11
VB. VARIABLE BILLOW)........................................................13
VB. MAINTENANCE..................................................................13
TUNING INSTRUCTIONS..........................................................14
BATTENS AND BATTEN PROFILE..........................................16
MAINTENANCE..........................................................................17
REPAIR........................................................................................19
RECOMMENDED COMPONENT LIFE.....................................19
TRANSPORTATION...................................................................20
SHORT PACKING.......................................................................20
TRANSPORTATION BY AIR.....................................................21
STORAGE....................................................................................22
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Cheetah 160 Owner’s Manual
TROUBLE SHOOTING...............................................................22
OWNERSHIP...............................................................................24
APPENDIX: LOSING THE KINGPOST- THE DIFFERENCES.25
APPENDIX: GLIDER OPTIONS.................................................27
APPENDIX: ASSEMBLY DRAWINGS......................................28
APPENDIX: CHECKING WASHOUT........................................32
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Cheetah 160 Owner’s Manual
INTRODUCTION
Congratulations on your purchase of an Avian Cheetah. The Cheetah represents the state of the art in high
performance, kingpost-less design. We hope that you will experience many hours of safe and enjoyable
flying on your new hang glider.
This manual is designed to help you get the most out of your Cheetah. Please read this manual completely
before flying, check all your battens against the batten profile adjusting them if necessary) and do a
thorough pre-flight check including checking the operation of the VB. This is especially important if
instruments are attached to the right hand VB.) upright. See page 12 'VB.' and page 21 'Trouble
Shooting.')
Please make sure your first flight on your new glider is in perfect conditions from a site that you are
familiar with. If you are uncertain, or have any problems with your glider, DO OT FLY. We have a
section on trouble shooting in this manual that features some of the more common problems that pilots
have encountered, and our recommended solutions. If you are still not sure contact your local dealer or the
Avian factory.
PLEASE OTE
Avian Ltd does not have commercial product liability insurance.
Avian hang gliders are built using materials and fittings to the industry standard or better. Avian hang
gliders are subject to Avian quality control and testing prior to delivery to the customer.
Once possession of the glider passes to the customer, its maintenance and condition becomes the
responsibility of the owner or pilot. Any concerns or queries about the glider's subsequent airworthiness
MUST be referred back to the local dealer or the Avian factory.
Hang gliders must be:
·stored correctly
·treated with respect
·checked before take off and after heavy landings
·flown within their flight envelopes
·regularly maintained
Failure to do any of these courts disaster.
Look after your aircraft!!
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Cheetah 160 Owner’s Manual
OPERATI G LIMITS
1. Minimum pilot rating: Advanced pilot.
2 Manoeuvres:
1. Aerobatic manoeuvres are not permitted.
2. Pitching the nose up or down more than 30 degrees from the
horizontal is not allowed.
3. Do not exceed more than 60 degrees of bank
4. Do not fly the glider inverted or backwards.
5. Do not fly with auxiliary power without factory approval.
6. Do not fly with more than one pilot
3. Hang Glider Payloads:
Pilot Clip in Min Max.
Weight range 12 Stone 15 Stone 4 lbs
168 lbs 213 lbs
76 Kg 97 Kg
4. Hang Point Position Range (Pitch trim)
The hang loop is attached straight to the keel and should be within the following range:
(Distances measured from the front of the keel without plastic bung to centre of hang loop.)
Max. forward position 62" or 1575mm
Maximum rearwards position. 64" or 1626mm
SPECIFICATIONS
Wing span 32' 9" 10 m
Wing area 160sq.ft 15 m2
Aspect ratio 7
Min sink rate 170ft/min 0.86m/s
wing loading = 1.5 lbs./ft2 7.5kg/m2)
Max. L/D ratio 14.3
Speed range* 15 - 70 mph. 24 - 113 km/h
Max. speed VNE turbulent air) 45mph 72km/h
Max speed VNE smooth air) 70mph 113km/h
Normal packed length 19' 4" 5.9m
Breakdown length 15' 2" 4.6m
Glider weight rigged 70 lbs. 32 Kg
Glider weight in bag 77 lbs. 35 Kg
*Speeds measured using Davron 808 vario-ASI system. VNE: Velocity Never Exceed.)
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Cheetah 160 Owner’s Manual
RIGGING THE CHEETAH
The glider can either be rigged flat on the ground, or with the glider supported on its control frame*. The
latter should only be attempted in light wind conditions but is useful in confined spaces or where the
terrain is likely to cause soiling or damage to the sail.
Flat rigging
1. Lay the glider on the ground with the nose pointing into wind. Unzip the bag and roll the glider so it is
the right way up. Take the bag off. If you tread on the inside of the bag any dirt that you get on it will
be transferred to the glider when you put the bag on later.)
2. Take the glider ties off and take the battens out from on top of the sail.
3. Making sure that you do not lift the tip high above the ground to ensure that you do not bend the nose
plates), move one wing out a little then the other. It is important to move both wings out slightly the
tip less than 1m) before moving through larger arcs. The reason for this is that the geometry of the
cross tubes does not allow one wing to be pulled out far without the other moving. If you do this
when the wings are nearly parallel the leverage you exert is very high. It is possible to put very high
loads where you might not at first imagine, bending the nose plates and worse.) Continue until both
wings are about three quarters of their maximum travel. If there is any resistance, stop and check to see
what is causing it. Free the problem before continuing. Do not attempt to force the wings apart. Lift
the wing preferably by the wing tip or by holding under the leading edge. If you must use the sail
hold it by the batten pocket ends on the trailing edge. to try and minimise trailing edge damage.)
4. As you open out the wings, the inner washout rods are moved out automatically. Sometimes they
might need lifting over the cross tubes. Make sure that their ends are aligned under the span-wise
batten.
5. Using the access zip at the back of the undersurface near the tip open out the outer washout rod and
insert over its spigot in the leading edge. Make sure it is under the span-wise batten and fully home.
The rod can be left sticking from the zip hole until the battens are inserted.
6. Put the bottom bar on and insert the two stainless pins from the back of the base bar and fit the safety
rings. PUT THE RINGS IN IMMEDIATELY. DO NOT LEAVE IT UNTIL LATER. Thread the VB.
cord through the cleat on the base bar. Tie a 'stop' knot in the end of the cord to prevent it being lost up
the upright.
7. Lay the battens on the ground and pair them up, red with green, and check that corresponding batten
pairs have the same profile. This is a good habit to get into as it will reduce the chances of taking off
on a glider with a turn caused by asymmetric shaped battens. Periodically the battens should be
checked against the batten profile and reprofiled if necessary.)
8. Insert the battens smoothly starting with the outer shortest) thinner diameter batten. Insert the batten
in the second from the tip batten pocket. The outer-most pocket is for the compression strut which is
inserted later in the rigging sequence.) Insert the other battens working from the tip towards the centre
chord. As the battens are inserted make sure the washout rods pass under the span-wise battens. On
a new glider a little silicon spray on the batten ends will help them slide in smoothly. Keeping the
trailing edge low and slowly easing the battens into their respective pockets will help increase batten
pocket and sail life.
* See appendix, options: Rear mounted upright top.
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Cheetah 160 Owner’s Manual
9. The glider can now be tensioned. Remove the split ring from the special bolt located through the rear
of the keel tube. Using the attached elastic cords initially and then holding the webbing, pull the cross
tube restraint webbing back. Check that the elastics are not twisted. Locate the stainless tang over the
stub of the bolt and replace the split ring. PUT THE RING IN IMMEDIATELY. DO NOT LEAVE IT
UNTIL LATER. If the tension feels too tight stop and see what is causing the problem. DO NOT
JUST FORCE IT. Consult the trouble shooting area of this manual for possible causes.)
10. Push the battens home the last little bit. With a new sail the battens may not go fully home unless
pushed. The batten elastics should be put on double on each batten. The compression strut nearest the
wing tip can only be inserted when the glider has been tensioned. It locates on a plastic cleat on the
leading edge. This batten or compression strut is profiled on the Cheetah. Like all the other top surface
battens the curve should be up. The top surface of the wing should be convex, not concave).
11. The under surface battens should also be inserted when the glider is tensioned. They should be pushed
home so that only the rope projects from the batten pocket. Put the most outboard U/S batten in first.
The under surface battens can be pushed home with another under surface batten.
12. Check that the inner washout rods are held out by their cords and after the other pre-flight checks make
sure that all the undersurface zips are done up.
13. Put in the nose batten. This is easier with the VB. on full. Some people prefer to put the nose batten in
before the wings are moved out at all or to leave the nose batten in the glider when packed. If you do
this don't forget to check its profile when you check the profile of the other battens.)
14. NB The VB. must not be pulled on if the glider is laid flat on the ground: doing so will twist the cross
tubes. The glider should be stood on its control frame before operation of the VB.
15. Make sure that the wires are not twisted, then stand the glider on its control frame and attach the swan
catch, pip pin and safety washer. When lifting the nose of the glider it can be held by the webbing
hold on loop while attaching the nose wires. This is useful in windy conditions.
16. Make sure that the nose catch is correctly attached and then put the nose cone on.
The glider is now fully rigged. You should now make sure that you do a thorough pre-flight check before
you fly.
We suggest that if there is significant wind that the glider is left flat on the ground, nose into wind and
securely weighted or tied down at the nose until you are ready to fly. In light winds the Cheetah may be
left standing on its 'A' frame tail into wind- but be wary of gusts of wind, thermals and dust devils. Keep a
close eye on it.
Rigging on the A-frame
This is useful in confined spaces or where the terrain is likely to cause soiling or damage to the sail.
1. Lay the glider on the ground. If there is any wind the nose should be pointing cross or down wind.
Unzip the bag and take off enough ties to assemble the A frame. Assemble the A frame. Put the
bottom bar on and insert the two stainless pins from the back of the base bar and fit the safety rings.
Put the rings in immediately - do not leave it until later. Thread the VB. cord through cleat on the base
bar. Tie a 'stop' knot in the end of the cord.
2. If the nose batten was left in the sail move it onto its location and then stand the glider on its A-frame.
Take the bag and remaining ties off and remove the battens from the top of the wing.
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Cheetah 160 Owner’s Manual
3. Open the wings slightly then walk the wings out to about three quarters of their full extension. As
before the wings should ideally be walked out together. If you are rigging by yourself move alternate
wings gradually apart. NB: Whilst spreading the wings, particularly when the glider is standing on its
A frame, it is essential that the leading edges and keel are kept in the same plane. This is to avoid
distortion to the nose plates or any other components.)
4. Take care to place the tips on a piece of ground that is not likely to cause them damage. Leave the tip
socks on as this will protect them. The glider should now be standing on its A frame, wing tips and
keel.
5. Making sure that the wires are not kinked, attach the nose swan catch, pip pin and safety washer.
6. Make sure the inner washout rods are out and sitting under the span-wise battens. The inner washout
rods will automatically come out as they are attached to the sail but can be helped by lifting them.
Never detach them from the sail as you may forget to re-attach them.)
7. Lay the battens on the ground and pair them up, red with green, and check that corresponding batten
pairs have the same profile. This is a good habit to get into as it will reduce the chances of taking off
on a glider with a turn caused by asymmetric shaped battens. Periodically all the battens should be
checked against the batten profile.)
8. Put the curved battens in their pockets working from the centre chord towards the tip. Keep the trailing
edge low and slowly ease the battens into their respective pockets. Check again that the inner washout
rods are under the span-wise battens. Do not put in the last four battens or compression strut. Leave
the tip socks on.
9. Make sure you have opened the wing as far as possible. Check that the inner washout rods are under
the span-wise battens. Tensioning the glider is made much easier with the help of a friend. Get him or
her to lift a wing tip, thus opening the wings out further. Tensioning is then easy.
10. Take off the tip socks open the zip at the tip and fold out the outer washout rod. The last few battens
can then be inserted into their pockets.
11. Next insert the compression struts and locate them on their plastic bracket on the leading edge. These
compression struts, are bent and should be profiled correctly and put in the right way up. Like all the
other battens the curve should be up. The top surface of the wing should be convex NOT concave.)
12. Push all the battens fully home. With a new sail the battens may not go fully home unless pushed.)
Then put on the batten elastics; double on each batten.
13. If not already in place, insert the nose batten and locate it on its seat just in front of the nose plate
Some pilots only remove the nose batten occasionally to check its profile.). This operation is easier if
the VB. is pulled on first. When the batten is in place release the VB. On the ground releasing the
VB. may require pulling the cross tubes forwards in the sail.)
14. The under surface battens are more easily inserted once the glider has been tensioned. They should be
pushed home so that only the rope projects from the batten pocket. Put the most outboard U/S batten
in first. The under surface battens can be pushed home with another under surface batten.
15. Double check that the nose catch is correctly attached and put the nose cone on.
The glider is now fully rigged and you should now make sure that you do a thorough pre-flight check
before you fly.
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Cheetah 160 Owner’s Manual
PRE-FLIGHT CHECK-LIST
Detailed pre-flight checks must be carried out during assembly. Always use the same assembly and
packing procedure which will help to eliminate mistakes. After rigging, a pre-flight check should always
be carried out. The following must be checked:
1. All tubes are straight and not dented. Any damage to carbon spars should be very closely inspected.
A small dent is very serious damage. See section on carbon fibre in the appendix.)
2. Nose plates and A frame fittings OK. All screws secure.
3. Check that all washout rods are out and correctly positioned under the span-wise battens. The inner
rods with their restraint cords attached.
4. Check that all sail seams are intact with no frayed stitching, particularly in high stress areas e.g. wing
tips, junction of keel pocket and sail etc.)
5. Check that the wing looks symmetrical with the correct shape. The battens should be correctly shaped
and undamaged.
6. All nuts and bolts secure.
7. All quick release fittings secure:
·cross tube tensioner.
·nose catch check the clevis pin and split ring as well)
·tip compression struts correctly located on the leading edge
·quick pins and rings secure on bottom bar
·outboard leading edge section fully engaged. Be especially vigilant if the L/E has been short
packed recently.)
8. Cross tube tensioner strop not frayed and twist free.
9. All zips done up.
10. Batten elastics symmetrical on both sides of the glider. They should also be in good condition and
engaged over the batten ends.
11. Hang loops in good condition.
12. The glider is symmetrical when viewed from the front.
13. Unzip the under surface and check the centre junction. With your fingers check that the cross tube
centre bolts are secure. Check that all webbing loops are in good condition. Sight down the cross
tubes and check they are undamaged.
14. Check the four nose plate bolts are secure.
15. Walking along the length of the leading edges feel with your fingers to check that they are free from
dents. Check that there is a similar leading edge curvature on both leading edges when looking down
the inside of the wing from the nose towards each wing tip.
16. Check through the sail inspection zip at the side wire to ensure that the wing wire and cross tube
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Cheetah 160 Owner’s Manual
leading edge bolts are secure.
17. Check that the keel is horizontally straight with a slight downwards bow. Check that the tensioning
strop is secure, correctly fitted and that the split ring is in place. As shown in the earlier diagram.
18. Check that the wires are undamaged. Look out for corrosion and fraying. Pay particular attention to
inspection of the side wires as, in normal flight, these are the most heavily loaded. I SPECT BOTH
E DS: THE BASE BAR E D A D THE CROSS TUBE JU CTIO E D. REMEMBER: IF
I DOUBT DO OT FLY- RETUR YOUR GLIDER FOR A THOROUGH STRIP-DOW .
19. Check operation of the VB. Pull the VB. rope and check that it pulls on smoothly and releases. If it is
jammed check and release if caught. If instruments are attached to the right hand upright it may
interfere with the VB. operation. The VB. cord runs down the rubber back of the right hand upright.
Crushing the rubber back impedes the movement of the cord. It may then be possible to pull the VB.
but not to release it. This is easily cured by inserting a length 30cm) of batten material inside the
rubber back of the upright and passing the VB cord through it. This stops the rubber back from being
crushed and the rope impeaded.) With a topless glider it may be necessary to unzip the centre zip and
pull the cross tube centre forwards to get the VB. to release while on the ground see appendix).
20. Finally check that all the quick release fasteners are secure. Pay particular attention to the base bar
quick pins. As the glider is moved and placed on the ground the safety rings in the base bar quick pins
may contact the ground. Long grass seems most likely to cause the problem but it is possible to
remove the safety ring from the pin. The problem is minimised if you put the pins in from the back of
the base bar. Thus when the glider is sitting on its keel the head of the pin will contact the ground
rather than the safety ring.) Special attention should be given to checking quick release fasteners.
FLYING THE CHEETAH
Please note the following is not meant to be an exhaustive fl ing manual but merel a brief note
and should be read with that in mind. It is recommended that our first flight on the Cheetah, is
from a site ou know well, using our normal fl ing gear in good weather conditions. (Don't
change more than one thing at a time.)
Take off
Before take-off make sure you've pre-flighted the glider, that you are clipped in and that you have
performed a hang check. On take-off the wings should be held level with the nose slightly raised. A strong
and committed take off run is always recommended. Keep the angle of attack low until you are running
fast. Once sufficient air speed has been achieved increase the angle of attack gradually to take off. Once
settled in flight, clear of the ground and obstacles, move your hands, one at a time, to a comfortable
position on the speed bar.
In Flight
The control in both pitch and roll is light and precise. Accordingly the glider should be flown with
moderate and precise inputs. The glider should not be flown too slow or in a semi-stalled condition as the
roll response becomes much slower.
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Cheetah 160 Owner’s Manual
Stall
The Cheetah recovers quickly from stalls but will lose height doing so. A wing close to the stall becomes
difficult to control. For both these reasons the glider should be flown with sufficient airspeed close to the
ground, hill or any other aircraft or obstacles.
S in
Hang gliders are generally resistant to spin. It is very unlikely that you will ever experience a spin in
normal flight. To recover from a spin pull the bar in and increase speed BEFORE applying opposite bank.
Flying when wet
DO NOT TEST YOUR NEW GLIDER IF IT IS WET. Wet gliders do not fly nearly as well as dry
gliders. This is because the water droplets on the leading edges disturb the airflow over the wing. The
result is that the glider does not perform so well and stalls at a much higher airspeed, so you will not be
able to fly the glider as slowly as if it were dry. You may also find that the glider stalls more easily, takes
longer to recover from a stall and is more prone to spinning.
If you get caught in the rain as the glider gets wetter you will notice the above effects increase. You will
have to fly faster to avoid stalling and should be especially careful when landing. We advise that you fly
with a lot of excess speed when doing any manoeuvres near the ground or other aircraft with a wet glider.
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Cheetah 160 Owner’s Manual
Landing the Cheetah
The secret of a good landing is:
·getting prepared for landing while you are still high,
·good field selection
·followed by a precise approach with plenty of airspeed.
Always plan your landings from high up, check that the VB. is in the fully released position and make sure
you can get your feet out of your harnesses well before landing. Check the surrounding air for other aircraft
preparing to land. Look and check that your approach and over-shoot path have as few obstacles as
possible. Never choose to land immediately behind other gliders or obstacles but land to one side. You'll
make a lot more friends!)
POST FLIGHT INSPECTION
After landing, especially if heavily, the glider should be inspected as outlined in the pre-flight inspection.
DE-RIGGING
Remember good de-rigging and packing of your glider will dramatically increase its life.
De-rigging is largely the reverse of the assembly sequence:
De-rigging the glider flat
1. Lay the glider flat on the ground and into wind. Loosen all the batten elastics and remove the
compression struts and under-surface battens. Remove the nose batten before releasing the cross tube
tension. If you intend to remove it from the sail.)
2. Release the cross tube tension and swing the wings in a few feet. Remove the remaining battens.
Remove all the battens smoothly. Pulling battens out excessivly quickly will increase wear of batten
ends and batten pockets.)
3. Unzip the outer zip and fold in the outer washout rod.
4. The wings can then be closed further.
5. Place the padding around the tension bolt. Bring the leading edges in further lifting the inner washout
rods and helping them lie alongside the leading edges. Dismantle the 'A' frame. Tie a 'stop' knot in
the VB. cord to prevent it being lost up the upright in transit. Attach the 'A' frame padding around the
bottom of upright castings. When packed the side wires should come out of the top of this packing.
All wires should be packed so they are not be kinked.
6. The wing tips can then be brought together. Next the sail should be rolled and tucked inside the
leading edge. One side can be rolled and retained with a tie and tip sock while the other is being done.
7. The battens can be stowed at the front of the glider between the leading edges with the curves over the
nose section. The ties can then be placed round the glider holding the leading edges neatly together.
Place the glider bag over the glider and then turn the glider on its back.
8. Put the speed bar in its bag and place it in the sail near the wing tip. Any remaining ties should be put
around the glider. Tuck the nose cone under the tie near the nose of the glider.
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Cheetah 160 Owner’s Manual
9. Zip the bag up and store the glider dry, in a cool, dry and dark place.
De-rigging the glider u right on the keel
This is useful in confined spaces or where the terrain is likely to cause soiling or damage to the sail. It is
essentially the reverse of rigging the glider on the keel:
1. Put the glider keel down and tail into wind. Remove the under-surface battens. Loosen all the batten
elastics and remove the compression struts.
2. Remove the outer 4 battens from each tip of the glider. Then unzip the outer zip and fold in the outer
washout rod. Roll the tip of the sail and put on the tip socks. This is so that when the tension is
released the tips are covered and protected from the ground.)
3. Release the X tube tension and move the wings in slightly. It might be necessary to undo the centre
zip and pull the cross tubes forward a little first.
4. Attach the tension bolt packing. The keel remains on the ground.
5. Remove the rest of the battens except the nose batten.
6. Remove nose cone and release the lower nose wires.
7. Bring the wings closer together making sure to lift the inner washout rods to lie them alongside the
leading edges. Pull the sail between the leading edge and keel so that it is all above the leading edge.
Roll it carefully and tuck it inside the leading edge. One side can be rolled and retained with a tie and
tip sock while the other is being done.
8. Remove the nose batten if you intend to. Put all the battens into their batten bag.
9. The battens can be stowed at the front of the glider between the leading edges with the curves over the
nose section. The ties can then be placed round the glider holding the leading edges neatly together.
Take off the ties holding the sail in place and put them around the whole glider in the normal way.
10. Place the glider bag over the glider and then turn the glider on its back.
11. Dismantle the 'A' frame. Tie a 'stop' knot in the VB. cord to prevent it being lost up the upright in
transit. Attach the 'A' frame padding which is located around the bottom of upright castings. When
packed the side wires should come smoothly out of the top of the packing and all wires should be
arranged with no kinks.
12. Put the speed bar into its bag and store in the sail near the wing tip. Any remaining ties should be put
around the glider. Tuck the nose cone under the tie near the nose of the glider.
13. Zip the bag up and store the glider dry, in a cool, dry and dark place.
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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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Cheetah 160 Owner’s Manual
VB. Set-up
The VB. on your glider should be factory set. However the ropes do stretch a little and it may be necessary
to adjust the ropes to retain full VB. Travel.
EVER ALTER YOUR GLIDER OR VB. I SUCH A WAY AS TO I CREASE THE
MAXIMUM TE SIO OR REDUCE THE MI IMUM TE SIO .
TUNING INSTRUCTIONS
Trim s eed
The trim speed is adjustable by moving the hang loop forwards or backwards along the keel. Forward
movement will speed trim the glider faster, whilst rearward movement will slow it down. Only move the
hang loops in small increments 5mm maximum). The factory setting for the position of the hang loops is
shown below:
Turns
A turn in the Cheetah is unusual. If your glider previously flew straight then the most likely explanation is
that you have damaged your glider. If a turn is detected first check the battens. Check them against each
other making sure that they are the same on both sides) and then against the profile. Next check that the
batten elastic tension is the same on both sides of the glider. If there is still a turn check that the leading
edges are straight and undamaged.
A slight turn may be tuned out using the adjustable tip caps. You will require one 5mm Allen key.
The black plastic tip caps are infinitely adjustable. They have a line marked on them and there is another
line marked on the leading edge. These references are aligned for initial assembly. The line on the leading
edge is the datum.
To loosen the cap so that it can be turned insert the Allen key and turn anti-clockwise a couple of turns. If
the cap of the Allen key starts to protrude give the key a sharp knock which will push the cap screw in.
Do not loosen too much.) It should now be possible to turn the tip with a little effort. The tension of the
sail is still pulling the cap tight into the leading edge.) When the tip is in the desired position re-tighten
the Allen screw. Do not over tighten it.
The washout should only be adjusted in small increments. MAXIMUM 1MM at a time.) The total
movement should OT exceed 10mm each side of the datum.
Which way to adjust the tip caps?
The wing that is lifting should have the washout increased i.e. trailing edge lifted) while the wing
dropping should have the washout reduced i.e. trailing edge lowered). Mark the leading edge with a pencil
before loosening the 5mm Allen screw so you know where you started. Make the adjustment and fly to
check the result. If large adjustments are required it is very likely that the glider is damaged in some other
way and a thorough examination or better still full strip-down inspection is recommended before further
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Cheetah 160 Owner’s Manual
flight.
Washout at the tips
The washout at the tips can also be altered symmetrically, that is increase or reduce the washout on both
wings. Only small changes are needed and large changes are counterproductive. A small reduction in the
washout 2mm) will make the glider feel slightly lighter in pitch and show perhaps a slight increase in
glide performance. In smooth air the glider handling will probably appear much the same but if a wing is
lifted it will be more difficult to get down.
Movement in the opposite direction will have the opposite effect. However it should be emphasised that
large movements are not beneficial.
To check the ideal tip cap setting. The glider should be flown clear of the ground and all other aircraft
with the VB. on. The under surface at the extreme tip of the sail should be just tight.
Batten Bungees
The tension of these bungees does make a difference to the handling of the glider. See Appendix for
batten numbering system.)
Battens number 1, 2 and 3 can be relatively tight.
Batten number 11 can be relatively tight but increasing tightness reduces handling.
The compression strut should be tighter and has thicker elastic but increasing tightness reduces handling.
The rest should be of medium to light tension.
Other tuning should OT be carried out without reference to Avian Ltd., or an approved dealer.
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Cheetah 160 Owner’s Manual
BATTENS AND BATTEN PROFILE
The Cheetah battens should be maintained in the correct profile. Failure to do this could result in adverse
flying characteristics.
Batten Material
The nose batten and compression struts are made from 1/2" OD 6082 aluminium alloy tubing.
All other battens are made from 10.8mm OD 7075 aluminium alloy tubing.
6082 Alloy tubing is softer and easier to bend. 7075 alloy is harder, more difficult to bend and more
brittle but it holds its shape much better.
How often should your battens be checked?
At first check your battens regularly. This will give you some idea of how fast they are changing profile.
The Cheetah has 7075 battens which tend to hold their shape well. The nose and tip battens are made of a
softer 6082 alloy. 6082 battens tend to get harder, and hold their shape better, once they have been re-
profiled a few times. On the Cheetah the batten most likely to require re-profiling is the nose batten.
Don't forget: If you don't know how the glider has been treated while it is out of your care for instance if it
has been sent by carrier or on an aeroplane) check the battens against the profile and do a very thorough
pre-flight check BEFORE flying.
Checking the profile
The best place to check the profile of your battens is at home on a flat surface. It is very difficult to do on
the hill with no flat surfaces and the wind blowing the paper profile away.)
The printed profile should be rolled out flat and a book placed at either end to hold it down.
The battens can then be compared to the profile:
Place green right) number 1 batten against number 1 profile. Place the front end of the batten against the
profile and check that it matches the profile along its whole length.
If it does not match the profile see where it deviates and adjust the batten accordingly in that area. See
below.) Continue this process until the batten matches the profile. Then do the same for red number 1
batten. Check that both number 1 battens are exactly the same shape. It is more important that the battens
are symmetrical than that they are a perfect copy of the profile. Asymmetrical battens could cause a turn in
your glider.
Move onto batten number 2 and so on until you have checked all the battens. Do not forget to check the
compression strut and that the under surface battens are straight.
ose batten
The nose batten profile should not be under-cambered but can be a little over-cambered. This is because
the cut of the sail will tend to flatten the batten if it is over-cambered. The objective with the nose batten is
to get the sail to fit tightly around the nose area.
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Cheetah 160 Owner’s Manual
Batten Profile
The batten profile is printed with the profile or shape that the battens should match. The profile is printed
with a photocopier so there may be a slight error in the length of the battens. 1-2%) Thus battens with
shape at each end should be aligned with the nearest end when checking the shape.
How to alter the shape of the batten
The objective is to get a smoothly curved batten but it is not quite as easy as it looks. It is very difficult to
bend the batten very close to its front end. Do not attempt to alter the profile over the first 3cm of the
batten. If your battens need profiling do the 6082 battens first as they are much softer.
To increase the curve in the batten hold the batten either side of where you want to increase the curve and
run the batten over your knee or leg exerting a gentle pressure. It helps if you are wearing something
slippery.) Compare with the profile and repeat if necessary. Try to avoid point bends and make sure that
the bends are all in the same plane. 7075 is a hard aluminium alloy and extra care must be taken while
profiling to avoid broken battens.) To reduce the curve, do the opposite of the above either over your knee
or preferably by pressing on a flat surface. If you have a point bend try and remove it.
MAINTENANCE
Annual strip down and factory inspection
Avian recommend that the Cheetah has a factory inspection every year or 100 flying hours which ever is
the sooner. This is a sensible precaution to take and is offered by Avian at special prices in the months of
December and January. An additional benefit of the strip down is that the latest upgrades can be fitted
sometimes for free.
General
Careful attention to the rigging and de-rigging sequences will reduce the risk of accidental damage.
Repairs should be undertaken by the Avian factory or an approved dealer using genuine Avian spares.
The correct storage of your glider will also greatly influence its life. The glider should always be stored:
·well packed
·completely dry
·well supported
·in a dark, cool and dry place.
Airframe Maintenance
Apart from damage caused by over stressing the glider i.e. crashing etc. the major wear and tear on the
glider happens in transit.
Aluminium Tubing
Care and consideration in de-rigging and transportation will pay dividends in airframe life. Damage to any
one of the structural members is serious and the only remedy is replacement. Insufficient care during
ground handling or transportation can lead to tube abrasion or indentation. The former accelerates fatigue
fracture and the latter reduces the strength of a component. Keep a regular watch for tell-tale hair-line
cracks. Although very rare cracksare most likely to occur in high stress areas such as around bolt holes. If
you bend, dent or damage the tubular members in any way, seek immediate professional advice before
flying again and have replacement parts fitted.
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Cheetah 160 Owner’s Manual
Carbon S ars
Carbon fibre spars must be looked after carefully. Damage to them is likely to be much less obvious than
to a metal tube. Any visible damage could signify serious structural damage and should be inspected by
Avian before flight.
Fasteners
Any fastener i.e. nuts bolts etc.) which is bent or shows signs of wear or corrosion should be replaced
immediately. Nyloc nuts should only be used ONCE. One clear thread of the bolt should stick out beyond
the end of the Nyloc. Nuts should be tightened only so that they are snug. In most applications on a hang
glider the nut is only there to stop the bolt from falling out. DO NOT OVER-TIGHTEN NUTS AND
BOLTS. Over-tightening them can crush the tubes and damage the hang glider.
Rigging Cables
The main danger with the rigging lies in kinking the cable. This is usually caused by careless rigging and
de-rigging or by over tightening the bolts that attach the tangs to the airframe. It should be possible to
swivel the tangs with light thumb pressure.) Once a cable has a kink the strands are damaged and
replacement is the only cure. The side cables are particularly important and should receive a frequent
detailed inspection. Check for cable damage along the length but the main failure area lies immediately
adjacent to the swaged fitting. Look carefully for signs of strand fracture at this position. Corrosion shows
itself as a white powdery deposit. Corrosion cannot be cured and the only answer, again, is replacement.
Even apparently undamaged rigging wires should be replaced every 200 hours*.
Cross tube tensioner
The stitching on the cross tube tensioner is easy to see and should be inspected frequently. The rest of the
tensioner strop is hidden in the sail and keel pocket so that any damage is more difficult to see. Thus do
take time to inspect this thoroughly, particularly around the VB. Pulleys and the cross tube centre junction
leveller. If any damage to the strop is found fraying, abrasions, cuts or wear to the stitching) the strop
should be changed before flying.
Wing fabric maintenance
Any cuts or tears at critical areas such as the trailing edge, sail fixing points or similar high load areas,
must be repaired at either the Avian factory or an Avian approved workshop. Small damage to panels,
leading edge covers etc., can be repaired with proprietary self adhesive tape. We define small damage as
abraded holes no more than 10mm diameter and small cuts no longer than 15mm. Anything larger should
be inspected by Avian approved personnel.
* For none standard wires see options. These require more regular changing.)
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Cheetah 160 Owner’s Manual
Stitching Damage
Thread damage never gets better and eventually runs. If you abrade a seam or damage the stitching in any
way, have the damage repaired before it gets worse. Small, non load-bearing areas can often be repaired in
situ by the tedious but effective method of hand sewing back through the original stitch holes. Use a needle
and only the correct polyester thread: available from Avian or most good sail makers.
Wing fabric cleaning
It is, without doubt, better to keep the wing clean than to try and clean it. Some dirt never comes off
completely. With a new glider avoid getting it dirty in the first place by careful rigging and de-rigging. If
you decide you do need to wash your wing, then select a dry day and have access to a good hose and clean
water supply. Never use bleaches, strong soaps or detergents. The soap residue can react with ultra violet
light and degrade the fabric. We recommend a very mild liquid soap washing-up liquid) and a soft
sponge. Gently wash the fully rigged wing, frequently hosing clean. Copious amounts of clean water will
not harm the wing and can be very beneficial in removing sand and grit which may get trapped inside the
sail. Usually in the nose or wing tip areas.) Removing stains from stitching is difficult. Resist the
temptation of scrubbing with a stiff brush as it might do more harm than good. Ensure that the wing is
completely dry before de-rigging and storing.
Battens
Battens form the wing shape and substantially influence the performance of the wing. They need treating
with care and, since they are subject to constant stress both during flight and rigging, they may lose their
shape. It is essential that they are checked against the template at frequent intervals and re-profiled if
necessary. See Section: Battens and Batten profile.)
REPAIR
The Cheetah airframe is deceptively simple, but like all aircraft requires skilled and qualified attention. We
do not recommend self repair or re-assembly by other than Avian or Avian nominated repair agents. No
replacement parts should be fitted unless they are factory supplied and identified as such. When ordering
spares always quote your glider serial number make a note of it if you have to replace your keel. It should
be recorded on the front of this manual). Bent aluminium tubes must never be straightened, always
replaced. Frayed cables and cables with damaged or twisted thimbles must always be replaced.
To help you identify components some of the main assemblies are shown in the appendix of this manual.
RECOMMENDED COMPONENT LIFE
The safe working life of the structural components of the Cheetah is dictated by the environment in which
the aircraft is used and the care taken during day to day operations. Inspection, therefore, is an essential
tool in deciding the continued use of most components, particularly the sail. UV exposure shortens the life
of the sail, which is why it should not be left needlessly exposed to sunlight or any other source of UV
radiation. Due to the nature of their material, construction and position within the structure, certain
components have a critical fatigue life and it is mandatory that these components are replaced within the
time stated below.
Cross Tubes 2000 hours
Leading Edges 1000 hours
Control frame / fittings 1000 hours
Keel 1000 hours
Rigging wires / Tension strop 200 hours
Factory inspection 100 hours or 1 year See maintenance)
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