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There are two important airspeeds with which all hang glider pilots should be intimately
familiar; minimum sink airspeed (hereinafter referred to as MSA) and minimum controllable
airspeed (MCA). 

The most important of these two is MCA. 

Minimum sink airspeed is that

speed at which your descent rate is the slowest possible. It is the speed to fly when you
want to maximize your climb rate in lift, or slow your rate of descent to a minimum in non
lifting air. (You would normally not fly at MSA in sinking air; the strategy there is normally to
speed up and fly quickly out of the sink. By minimizing your time spent in the sinking air you
minimize altitude lost, even though you have momentarily increased your sink rate by speed-
ing up.)

Minimum controllable airspeed

 is that speed below which you begin to rapidly lose effec-

tive lateral control of the glider. Recognition of this speed and its implications is a more
subtle problem than many pilots realize. We have seen several instances of pilots who were
having a lot of trouble flying their gliders simply because they were unknowingly trying to fly
them too slowly; below the speed at which the glider responded effectively to lateral control
inputs. It is our opinion that a great percentage of hang gliding accidents are caused by
inadvertent flight below MCA, and subsequent loss of control of the glider with impact pre-
ceding recovery. Such incidents are usually attributed to “stalls,” but it is not the stall per se
that causes the problem, indeed the glider need not even be “stalled” in the traditional sense.

There is no necessary cause and effect relationship between minimum sink speed and
minimum controllable airspeed. MSA is determined primarily by the wing loading and span
loading, the wing planform, the wing section characteristics, etc. MCA is influenced most
heavily by the tension in the sail; how much “billow” the glider has. However, in your Wills
Wing glider, as in most hang gliders, MCA and MSA evolved towards a common value during
the design and development of the glider. This is so because if the wing is tuned so tight that
minimum controllable airspeed is at a higher speed than minimum sink speed, then effective
sink rate performance can be improved by loosening the wing so as to lower the minimum
controllable airspeed. Conversely, if minimum controllable airspeed is reached at a speed
below that of minimum sink, the wing can usually be tightened so as to improve glide perfor-
mance without significant sacrifice in other areas.

USING WING TUFTS TO FIND THE MINIMUM SINK SPEED OF YOUR GLIDER

On a flex wing hang glider, the wing experiences a gradual and progressive stall, and differ-
ent spanwise stations of the wing stall at different angles of attack. Contrary to popular
belief, a hang glider wing does not stall first in the root or center section. It is true that
because of wing twist the root section is at the highest angle of attack relative to the remote
free stream airflow, but other factors influence the stall propagation on the wing. Specifically,
a flex wing hang glider stalls first somewhere outboard of the root on each wing, approxi-
mately one fifth to one third of the way out from the root to the tip, where your tufts are
located. As the angle of attack is raised further, the stall propagates both outward towards
the tips and inward towards the root.  If you wish to observe the stall propagation across the
whole wing on your glider, you can cut some more tufts from knitting yarn, about 3-4" long,
and tape these to the top surface of your sail across the rest of the span.

During normal flight the flow will be chordwise along the wing, and the tufts will point towards
the trailing edge. When the wing stalls, the tufts will reverse direction, indicating the local
flow towards the leading edge.

Содержание RamAir 146

Страница 1: ...5 Phone 714 998 6359 FAX 714 998 0647 Revised 3 24 94 5th Edition Copyright 1993 by Sport Kites Inc dba Wills Wing Inc All rights reserved No part of this manual may be reproduced in any form without...

Страница 2: ...Up and Preflight 9 22 Launching and Flying 23 Trimming The Glider In Pitch and Speeds to Fly 23 27 Using The VG System 28 29 Landing 29 31 Breakdown 31 32 Stability Systems 32 38 Maintenance 38 39 Rem...

Страница 3: ...hroughout the world since 1973 We encourage you to read this manual thoroughly for information on the proper use and maintenance of your Wills Wing glider If at any time you have questions about your...

Страница 4: ...gth so that the thread is stretched under tension and therefore does not sag measureably across the span of its length At each of the three VG settings measure the height above the top surface of the...

Страница 5: ...ang loop adjustment The parts are available free of charge through Wills Wing dealers world wide Installation instructions follow Batten Reflex Modification The 154 has reflex added to 4 battens no 8...

Страница 6: ...n known to slip RamAir154 2 75 inches 7 0 cms RamAir146 4 75 inches 12 0 cms Tighten both knots firmly using pliers if necessary Support the rear keel at the rear wire station and pull down on the bri...

Страница 7: ...s are looser than specified optimum stability will not be achieved A final evaluation of the bridle adjustment should be made by flying the glider in a steady state pilot full forward dive at each of...

Страница 8: ...certificates Wills Wing hang gliding products are not covered by product liability insur ance As a hang glider pilot you are entirely responsible for your own safety You should never attempt to fly a...

Страница 9: ...nd of the range and the rate of application of pitch is moderately rapid The RamAir can be induced to spin at any VG setting Recovery from a spin requires unstalling of the wing and it is therefore cr...

Страница 10: ...s hooking in within 20 lbs of the maximum will experience some relative degradation of optimum sink rate perfor mance due to their higher wing loading A minimum USHGA Advanced IV level of pilot profic...

Страница 11: ...e six inches from the rear end is a 58 mm diameter ryton plastic crescent reducer which is secured in place by a 3 16 clevis pin which passes all the way through the 60 mm front leading edge See diagr...

Страница 12: ...re assembly 4 On a late model sail after September 1993 the mylar can be removed at this time Remove the top plastic kingpost cap and disconnect the top side wire from the kingpost Replace the cap Pul...

Страница 13: ...ge during break down 4 Pull the sail down the leading edge and re install the mylar if removed The mylar is most easily installed by attaching it to a long pole and pushing it into the pocket 5 Re ins...

Страница 14: ...e folding basetube Preflight the folding basetube center hardware at this time checking that the nuts and coil spring pins are secure and that the tangs are straight and in good condition Slide the ba...

Страница 15: ...the head of the keyhole bolt at the rear wire station on the keel 5 Insert the rounded end of the swan catch lever without the thumb handle extension into the rear pin channel in the swan catch bracke...

Страница 16: ...he wings almost all the way If you have left the bridles attached this will automatically stand the kingpost upright If not lift on the top side wire as you spread the second wing and the kingpost wil...

Страница 17: ...ttens carefully so as to minimize stress and wear on the sail Never insert or remove top surface battens with the crossbar tensioned except for up to the last four on each side and never insert or rem...

Страница 18: ...ocked position STOP Never install the keyhole channel onto the keyhole bolt without making absolutely sure that the channel is fully engaged on the narrow neck of the bolt and slid forward into the fu...

Страница 19: ...aft crescent reducer make sure it is fully engaged in the 60 mm front leading edge tube e The front crescent reducer clevis pin and safety f The crossbar leading edge junction bolt castle nut and saf...

Страница 20: ...tch pin is fully engaged in the hole in the swan lever and passes through and extends beyond the other side of the channel An inadvertent release of the swan lever from the swan catch channel in fligh...

Страница 21: ...mplete preflight of the glider checking all assemblies which have not al ready been checked ALONG THE LEFT LEADING EDGE Carefully check the entire length of the leading edge pocket to insure that the...

Страница 22: ...flight failure in normal operation Open the crossbar junction access zipper and look inside making sure that the safety ring on the junction bolt is in place and that the wires are secure and properly...

Страница 23: ...the condition of the kingpost base compensator pulleys and check that the lower compensator cables are properly routed around the pulleys and are in good condition Pull the top edge of the seal away f...

Страница 24: ...uding the clevis pin safeties the control bar top plug bolts and nuts and the elbow to apex slider bolt and nut Check the main and backup hang loops a Check all three oval quick links to insure that t...

Страница 25: ...ding fatigue and eventual failure of the swan lever wire Open the center zipper and check the routing of the VG rope around the pulleys and that the pulleys are properly aligned and not twisted or tan...

Страница 26: ...cone Pull down on the swan lever cable to slacken it and then release the forward swan lever pin Support the nose of the glider and release the rear swan lever pin If the control bar apex does not im...

Страница 27: ...the bottom front rear and side wires If the wind is more than 10 mph or gusty you should have an assistant on your nose wires on launch and if necessary an assistant on one or both side wires Make sur...

Страница 28: ...s etc MCA is influenced most heavily by the tension in the sail how much billow the glider has However in your Wills Wing glider as in most hang gliders MCA and MSA evolved towards a common value duri...

Страница 29: ...me at your tufts That is why familiarization with these other more accessible indicators is important After finding your minimum sink speed experiment with roll control response at speeds just above a...

Страница 30: ...t they cannot catch on any seam will minimize the problem of sticking TRIMMING YOUR GLIDER IN PITCH The fore and aft location along the keel of your hang point is commonly if mistakenly re ferred to a...

Страница 31: ...hite This is the range from 20 mph to 30 mph This is the normal thermalling speed range for light to moderate thermalling conditions Try to keep your speed within this range when thermalling in light...

Страница 32: ...st ments of no more than half that amount at one time The recommended procedure for in creasing VG tension is to grasp the rope firmly at the cleat and pull straight across behind the basetube Two dif...

Страница 33: ...an 5 mph if the slope is steeper than 12 1 you should seriously consider landing downwind and uphill or crosswind and across the slope Making your approach VG full loose to VG 1 3 will also increase t...

Страница 34: ...i cantly give a sharp aggressive flare pushing your arms and shoulders forward and your hips legs and feet backwards The braking effect of the flare will allow your feet to swing under you as the glid...

Страница 35: ...nd put aside Remove any instruments 2 You must at least detension the swan lever before you will be able to detension the cross bar If you plan to break the glider down flat completely disconnect the...

Страница 36: ...er over onto it s back 8 Fold up the basetube Replace all protective bags as you pack the glider away STOP When folding in the folding basetube take care to avoid two problems a Do not fold the basetu...

Страница 37: ...ed to the crossbar center hinge runs around a pulley in the base of the kingpost up inside the kingpost and around another pulley attached to the upper compensa tor wire and then back down and around...

Страница 38: ...hich will slacken the lower compensator as the bridles are let down onto the backup pigtail Using the mark on the cord as a guide tie the knot below the compensator tang to fix the adjustment of the c...

Страница 39: ...le Outer Loose Just Slack Slack Quite Slack Middle Just Slack Just Slack Slack Tight Just Slack Just Slack Slack to to snug Just Slack In order to sight the bridles use the following procedure For eac...

Страница 40: ...n the 146 Numbers at the left are approximate total pounds of force felt on the bar The acceptable range indicates the allowable variations in these total force numbers Likely Causes of Pitch Pressure...

Страница 41: ...of the bridles is also affected by other aspects of the glider geom etry For example if the bottom side wires are too long it will allow the wings to rise and slacken the bridles in normal flight If t...

Страница 42: ...ain your glider may lead to a dangerous loss of strength stability or control responsiveness of the glider Following any mishap that results in damage to the glider immediately have any damaged compon...

Страница 43: ...led in accordance with the recommended annual inspection procedure All frame parts will need to be disassembled including the removal of all sleeves and bushings flushed liberally with fresh water dri...

Страница 44: ...isconnect the bridles from the sail 6 Remove the screw that holds the kingpost top cap in place and carefully remove the cap Remove the top front and top side wires from the kingpost top Re install th...

Страница 45: ...rossbar leading edge junction and are not wrapped around the frame 4 Position the frame with the bottom of the noseplate facing up and with the rear end of the leading edges at the nose of the sail Sl...

Страница 46: ...nual on bridle adjustment 14 Re adjust the nose sail mount string so that it is slightly slack with the crossbar tensioned Do a very careful and complete pre flight of the glider according to the norm...

Страница 47: ...ite tight and when they are properly adjusted you will not be able to install them unless the crossbar is tensioned LEADING EDGE SAIL TENSION The tension in the leading edge of the sail adjustable by...

Страница 48: ...sail from sunlight is probably the limiting factor in the life of your sail Try to avoid exposing your sail to sunlight any time you are not actually flying it We also know that there are forces in n...

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