Lite Machines LMH-110 Скачать руководство пользователя страница 41

Dynamic Balancing

If the main rotor blades are tracking properly, but the helicopter still vibrates
noticeably, the main rotor may not be properly balanced. To dynamically balance the
main rotor without removing it from the helicopter, stick a small piece of blade
balancing tape to one of the main rotor blades and run the main rotor at flight speed. If
the vibration level decreases, the extra weight of the trim tape is improving the
balance. If the vibration increases then remove the tape, stick it to the opposite blade
and spin the main rotor again. Try different sizes of trim tape until you find one that
minimizes the vibration. Repeat this procedure for the 

Arlton Subrotor

 stabilizer.

Helicopter Stability

Helicopters by their nature are not positively stable. At best, they are neutrally stable.
The concepts of positive stability and neutral stability can be illustrated by placing 
marbles in a bowl and on a table top as shown in Fig. 5-3.

He li cop ter sta bil ity

If you nudge the marble in the bowl with your finger, it will roll back and forth and
finally come to rest where it started in the center of the bowl. This is positive stability;
the marble always ends up where it started. If, on the other hand, you push the marble 
on the table, it will continue to roll until you stop it, and will sit still until you push it
again. This is neutral stability; the marble stays put until pushed, and keeps moving
until stopped.

Helicopters act like the marble on the table. When correctly trimmed they tend to
remain in one spot until moved, and tend to keep moving until stopped. Unlike the
marble, however, helicopters vibrate and fly in air that is always swirling and rolling.
As a result they do not stay in one place for very long, and require constant small
control inputs to hover over a spot on the ground. The marble on the table would act
more like a helicopter if you shook the table and tilted it back and forth. You would
have to constantly push the marble from different directions to keep it in one spot. 

Op er a tor's Guide

Main Rotor Stability and Control

LITE MA CHINES    

5-3

Figure 5-3.

Содержание LMH-110

Страница 1: ...onsiderable time making this product reliable and easy to build but only the operator can ensure that it is safe Because the safe operation of this helicopter is beyond the control of the manufacturer...

Страница 2: ...ail rotor blades Arlton Subrotor stabilizer Arlton Gyro stabilizer swashplate fuselage structure and configuration radio installation configuration landing gear and drive train are either patented U S...

Страница 3: ...ory of Electric Power 3 1 Batteries 3 2 Electro Magnetism and Electric Motors 3 2 Brushed motors 3 3 Adjustable Timing 3 4 Brushless Motors 3 5 Problems with Brushed Motors 3 6 Three Minute Motor Over...

Страница 4: ...nd Control 5 1 Rotor Blade Designations 5 1 Blade Tracking 5 1 Dynamic Balancing 5 3 Helicopter Stability 5 3 Adjusting Main Rotor Blade Pitch 5 4 Stability and Climb Performance 5 4 Learning to Fly 6...

Страница 5: ...irs with CA and Glass Fiber 7 4 Making Repairs with CA and Baking Soda 7 5 Fixing a Bent Tail Boom 7 5 Straightening a Bent Main Shaft 7 5 How Helicopters Work 8 1 Introduction 8 1 Background and Hist...

Страница 6: ...ng that could start a fire if exposed to fuel such as shorting or sparking battery terminals or the furnace in your home 6 Remove excess fuel from your model with a cloth after refueling or priming Ra...

Страница 7: ...model engines designed specifically for your Lite Machines helicopter Use of more powerful engines such as racing engines is potentially dangerous and voids all warranties 6 Do not use fuel containing...

Страница 8: ...irth defects General Safety 1 Periodically check tightness off all bolts nuts set screws and pins Loose parts could be ejected from your model causing injury or causing the model to crash 2 Replace br...

Страница 9: ...Guide Hint If you want lasting respect from helicopter flyers don t call the main rotor and tail rotor blades propellers and don t call the right left cyclic pronounced sigh click and fore aft cyclic...

Страница 10: ...tips the main rotor left and right like aileron control on an airplane O Stick pitch As shown in Fig 2 3 moving the stick forward and backward up and down tips the main rotor forward and backward lik...

Страница 11: ...g a car Note that the left stick rotates the NOSE to the left and right Always concentrate on the NOSE when using the left stick to turn You will become confused if you watch the tail O Stick throttle...

Страница 12: ...ands on transmitter To control your helicopter more accurately hold the control sticks with both your thumbs and index fingers as shown in Fig 2 6 It also helps to wear a transmitter neck strap to sup...

Страница 13: ...al and error A basic understanding of electric powered flight however will greatly aid you in successfully operating your Corona helicopter Basic Theory of Electric Power Electricity is commonly measu...

Страница 14: ...andard six cell pack produce about 7 2 volts 1 2V x 6 cells 7 2 volts Seven cells connected in series produce about 8 4 volts 1 2V x 7 cells 8 4 volts Battery capacity is measured in milliampere hours...

Страница 15: ...through carbon brushes that slide on a copper commutator ring attached to the motor output shaft as shown in Fig 3 1 The commutator ring generally has three segments attached to three coils of copper...

Страница 16: ...de the motor O Brushed eff graph As shown in Fig 3 2 which is a graph of motor efficiency at various motor speeds brushed motors are most efficient within a very small speed range Outside of this rang...

Страница 17: ...speed controller turns the coils on and off at the appropriate time to operate the motor at a particular speed Brushless motors are more difficult and expensive to manufacture than brushed motors but...

Страница 18: ...manufacturers say certain lubricating components are burned out further accelerating brush wear Once a brush has worn down to the point where it no longer touches the commutator it must be replaced I...

Страница 19: ...r can O Worn brush and comm 6 Inspect the brushes If the brushes are less than 3 16 5 mm long or if the brushes are burnt and discolored replace with new ones Warning DO NOT USE REPLACEMENT BRUSHES WI...

Страница 20: ...ator surface is smooth but dark and discolored clean it with a LiteBrite commutator cleaning pad until it is a shiny copper color six to ten twists by hand as shown in Fig 3 6 O Comm clean 2 9 Run a h...

Страница 21: ...e internal locking ring The Fusion 35 Speed Controller The Fusion 35 brushed motor speed controller by Castle Creations is a specially designed microprocessor based switching controller capable of del...

Страница 22: ...ETHER TO AVOID A SHORT CIRCUIT Arming the Fusion 35 To reduce the possibility of accidental starting of the main rotor blades the Fusion 35 controller will not deliver motor power until it is armed To...

Страница 23: ...bs This will reduce electrical noise After modifying or adding filter capacitors always test your motor controller and radio before flying Warning DO NOT USE TANTALUM OR ELECTROLYTIC CAPACITORS AS ELE...

Страница 24: ...dio control system To do so you must first cut the red power wire from your Fusion 35 controller to the receiver contact Castle Creations before doing this Insulate the exposed end of the cut wire so...

Страница 25: ...is a good idea to time your flights with a watch This will insure you are close to the ground when the batteries get low Warning NEVER STORE BATTERIES IN A CHARGED STATE OR CARRY CHARGED BATTERIES TOG...

Страница 26: ...The Corona flies best with an Electro Fusion 6 motor and six cell battery at a weight of about 42 ounces 1190 g While the Corona will lift more weight than this too much weight can overload a brushed...

Страница 27: ...SSISTANCE OR HURT YOURSELF WHILE OPERATING YOUR HELICOPTER ADULT SUPERVISION IS STRONGLY RECOMMENDED FOR MINORS Operating conditions can affect engine life Helicopters operate close to the ground and...

Страница 28: ...5000 ft or 1524m at Denver Colorado USA you will use fewer washers under the glow plug than at a lower elevation 700 ft or 213m at Lafayette Indiana USA Also if you fly when the outside air temperatu...

Страница 29: ...e engines will run on these fuels for a flight or two but then loose power Some engines will not start at all Do not use fuels that contain chemical additives such as anti rust compounds with your Nor...

Страница 30: ...ow head without the heat sink your engine will overheat and seize NEVER run your engine a test stand without an airplane propeller The propeller not only cools the engine but produces drag which keeps...

Страница 31: ...OTECTION AS WELL PROPER EYEWEAR NOT ONLY HELPS PROTECT YOUR EYES FROM THE SPINNING ROTORS BUT ALSO FROM OIL DROPLETS AND DEBRIS THROWN OUTWARD BY THE SPINNING ENGINE AND CLUTCH 3 Fill the fuel tank to...

Страница 32: ...ING RANGE OF THE RADIO 6 Fully extend the transmitter antenna before starting the engine 7 If starting the engine for the first time carefully turn the needle valve clockwise with a small screwdriver...

Страница 33: ...e best way to power a Lite Machines or Norvel glow plug is with a DuBro Kwik Start clip Never wire the glow plug directly to 12 volts like your car battery or the plug will burn out 10 Connect the glo...

Страница 34: ...cally locked Do not force it to turn or you could damage the engine Remove the heat sink and glow plug and spin the engine with the electric starter for one second to clear the excess fuel from the cy...

Страница 35: ...transmitter and knows to never move the cyclic controls right stick while the rotors are turning Hold your helicopter by the canopy and front landing gear struts as shown in Fig 4 3 with the main roto...

Страница 36: ...some point you will hear it slow down again This mixture setting is too lean The optimum needle valve setting lies about half way between the rich and lean settings It is best to operate with a sligh...

Страница 37: ...glow plug must glow bright orange To test a glow plug connect it to a glow plug battery with a glow plug clip and cup your hands around the plug to keep it out of direct sunlight BE CAREFUL THE PLUG W...

Страница 38: ...glow plug will stop working just as the starter motor begins to spin the engine so the engine may not start The plug will heat up again when the starter motor is turned off making it appear as though...

Страница 39: ...o the tip of the tail rotor blade Blade pitch is relative to the blade grip Warning Series 2 main rotor blades are susceptible to damage by solvents and other chemicals DO NOT USE SOLVENTS SUCH AS ACE...

Страница 40: ...t batteries are completely charged as per the manufacturer s instructions If the radio batteries die while you are flying you will lose control and crash O Tracking in As the main rotor spins look at...

Страница 41: ...3 Helicopter stability If you nudge the marble in the bowl with your finger it will roll back and forth and finally come to rest where it started in the center of the bowl This is positive stability...

Страница 42: ...sts The rotor blades can also generate the high aerodynamic air forces needed to forcefully push the helicopter around when the pilot moves the controls On fixed pitch helicopters helicopter weight an...

Страница 43: ...especially in windy conditions Although it may seem odd to purposefully add weight to a flying machine the additional weight requires a higher rotor speed to lift off the ground This high rotor speed...

Страница 44: ...are a good source of information and many have flight instructors Note however that advice from modelers can be highly subjective so talk to several individuals and refer frequently to this Operator s...

Страница 45: ...than concrete for the occasional unintended landing Training Gear Use training gear while learning to hover Training gear consists of two light wooden dowel rods attached to the landing gear of your h...

Страница 46: ...SE with the left stick as the model moves forward Do not look at the tail when steering your helicopter Drive around without actually leaving the ground until you have mastered steering with your left...

Страница 47: ...with the left stick increase the throttle until your helicopter is at least three feet off the ground where the air is less turbulent and use the right stick to hover over a spot It will be difficult...

Страница 48: ...e 3 the controls are neutralized and the helicopter starts moving sideways In Frame 4 with the controls still neutralized the helicopter is moving rapidly It takes time to accelerate a helicopter afte...

Страница 49: ...successful Hovering a helicopter is one of the most difficult piloting skills to learn and NOBODY learns to fly a model helicopter without crashing several times Most people require several hours of p...

Страница 50: ...flow through again as illustrated in Fig 6 5 O Forward flight As the helicopter starts moving forward it moves into cleaner undisturbed air as illustrated by Fig 6 6 The main rotor is more efficient i...

Страница 51: ...ing a helicopter in windy conditions can be difficult and requires continuous throttle control inputs as the wind speed changes Tail rotors are also affected by translational lift Forward motion and w...

Страница 52: ...osition with the right stick Notice that speed and altitude are related As the model picks up speed it gains altitude due to translational lift Note too that the tail rotor produces translational lift...

Страница 53: ...long enough to experience nose in flight but short enough to avoid becoming disoriented Practice both left hand and right hand figure 8 s After mastering figure 8 s try hovering nose in with the nose...

Страница 54: ...s during descents It is easier to judge forward speed when viewing the model from the side while it is circling rather than from the front when it is coming straight at you When decending from altitud...

Страница 55: ...tantaneously If you suddenly increase or decrease throttle the change in engine torque will cause the tail to swing Electronic gyro stabilizers such as piezo gyros sense rotational motion of the helic...

Страница 56: ...the Arlton Gyro stabilizer If the gyro is more effective in one turn direction than in the other or if the gyro paddles are tilted during hover the tail rotor blades may not be properly counter balan...

Страница 57: ...ons and the switch harness Keep the rotor blades clean of sand and dirt for best performance Other than incorrect assembly most ongoing problems with helicopters are directly traceable to poor mainten...

Страница 58: ...day Check for loose missing servo mounting screws every 30 flights Check servo travel every 30 flights servos should move smoothly Check servo speed every 30 flights servos should move quickly to max...

Страница 59: ...HEN ROTATING AT HIGH SPEED AND CAUSE SERIOUS INJURIES Use only glass cleaners that are safe for plastic eye glass lenses Warning DO NOT ATTEMPT TO REPAIR ROTOR BLADES REPAIRED BLADES CAN FAIL WITHOUT...

Страница 60: ...h to fit the patch area Hint Fiberglass cloth does not easily bend around sharp edges If you are repairing the plywood crutch on your helicopter apply a separate patch to both sides of the plywood rat...

Страница 61: ...ill not affect the flight qualities of your Lite Machines helicopter A bent boom can usually be straightened by hand several times before being replaced Small dents can be removed by pushing a 3 8 10m...

Страница 62: ...I am perfectly content with a simple two channel Cox 049 powered F6F Hellcat that I built from scratch in a weekend from Styrofoam and Econocote for about 10 My brother Dave is just the opposite He r...

Страница 63: ...l aircraft As a result scaled down model helicopters were typically unstable uncontrollable and underpowered In the 1970 s hobbyists most notably Dieter Shl ter in Germany developed the first practica...

Страница 64: ...helicopter in horizontal flight the pilot causes the main rotor to tilt slightly in one direction or another The offset lift force produced by the tilted main rotor causes the helicopter to move in t...

Страница 65: ...e As such the rotor obeys the physical laws of gyroscopes The basic operating principles of gyroscopes are not obvious so read the next sentence over a few times because this rule of thumb is the key...

Страница 66: ...f the fuselage and to a low angle of attack around the left side of the fuselage The aerodynamic forces produced by this difference in angle of attack cause the blades to flap upward 90 degrees later...

Страница 67: ...s The difference in lift produced on either side of the helicopter causes the main rotor blades to flap up and down and the rotor disk appears to tilt The tilted rotor disk produces a sideways thrust...

Страница 68: ...ng Blade Stall Retreating blade stall also referred to as asymmetric lift affects helicopter rotors that are moving forward translating As A Lite Machines helicopter moves forward the blade swinging f...

Страница 69: ...not changed materially for over 25 years For reasons of structure and simplicity and to minimize actuation forces tail rotor blades traditionally employ symmetrical cross sections such as a NACA 0012...

Страница 70: ...al mechanism that attaches to the tail rotor of a helicopter and performs the same function as an electronic gyro It operates under the same physical laws governing electro mechanical gyros see the ru...

Страница 71: ...this is similar in concept to delta hinges on a main rotor So essentially turning motion of the helicopter causes the paddles to tilt and the tilted paddles then push themselves upright OGYRCTRL It is...

Страница 72: ...t to tilting forces but the rule says nothing about moving the whole gyro back and forth In fact linear non tilting motion of the gyro has no effect on the gyro whatsoever This means that the gyro wil...

Страница 73: ...are provided at the root of each blade for fine tuning the pitching forces If the blades are not completely pitch balanced the gyro will tilt slightly even when the helicopter is not turning In this c...

Страница 74: ...atteries Glow plug voltage low Check glow plug battery or power panel for proper operation Engine not primed not enough fuel Hold finger over carburetor inlet and spin engine to pull fuel into carbure...

Страница 75: ...tarts popping Engine pops fuel sizzles fuel drips out of carburetor Engine flooded too much fuel Close needle valve and try starting engine to burn off excess fuel Open needle valve and try starting e...

Страница 76: ...high fuel pre detonating Add glow plug washers Bad old fuel Buy new fuel change brands fuel must contain castor oil Do not use fuel containing rust inhibitors Do not use dirty fuel containers Bad old...

Страница 77: ...gh fuel pre detonating Add glow plug washer s Bad ball bearing on main rotor or tail rotor Replace bearing bad bearing may not be noticeable when turned by hand or may feel slightly gritty Gear mesh t...

Страница 78: ...essary apply a very small amount of thread lock temporary type to heat sink threads New engine not completely broken in Follow manufactures break in instructions Improper fuel engine seizing Use fuel...

Страница 79: ...with oil Clean engine starter cone and rubber insert on electric starter motor with a paper towel Engine runs for many flights but then runs poorly or does not start Carburetor clogged Remove needle v...

Страница 80: ...gear mesh Ball bearing dragging Replace main shaft and or tail rotor bearings Swashplate dragging Lubricate swashplate with Lite Lube grease Filter capacitors installed Remove filter capacitors Motor...

Страница 81: ...e battery power BEC not supplying adequate voltage to gyro Use separate receiver battery Motor turns backwards Motor connections backwards Reverse power cables on motor DO NOT CHANGE POWER CABLES ON B...

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