How helicopters fly and are controlled

How helicopters fly and are controlled

http://rc-avti.si/sl/

Why helicopters are so versatile

A normal airplane can fly forwards, climb upwards, dive downwards and turn (and roll) to the left and right. A helicopter can do all this plus has the ability to fly backwards, move sideways in any direction, rotate 360 degrees on the spot and hover i.e. stay airborne with no directional movement at all.

Helicopters might be more limited in their speed than planes, but the
incredible maneuverability mentioned above is what makes them so useful
in so many different situations.

Above: the directions a helicopter can move in and the associated name of control.

Controlling a helicopter

Helicopters require a completely different method of control than
airplanes and are much harder to master. Flying a helicopter requires
constant concentration by the pilot and a near-continuous flow of minute
control corrections.


A conventional helicopter has its main rotor above the fuselage, just aft of the cockpit area, consisting of 2 or more rotor blades extending out from a central rotor head, or hub, assembly.


A primary component is the swashplate located at the
base of the rotor head. This swashplate consists of one non-revolving
disc and one revolving disc mounted directly on top. The swashplate is
connected to the cockpit control stick and lever and can be made to tilt
in any direction, according to the cyclic stick movement made by the
pilot, or moved up and down according to the collective lever movement.


But first, to explain how the main rotor blades are moved by the pilot to control the helicopter, we need to understand pitch angle...

The basics of pitch angle

Each rotor blade has an airfoil profile just like that of an airplane
wing, and as the blades rotate through the air they generate lift in
exactly the same way as an airplane wing does [read about that here].
The amount of lift generated is determined by the pitch angle (and speed) of each rotor blade as it moves through the air. Pitch angle is known as the Angle of Attack when the rotors are in motion, as shown below:





This pitch angle of the blades is controlled in two ways - collectively and cyclically....

Collective pitch control

The collective control is made by moving a lever that rises up from
the cockpit floor to the left of the pilot's seat, which in turn raises or lowers the swashplate on the main rotor shaft, without tilting it.

This lever only moves up and down and corresponds directly to the
desired movement of the helicopter; lifting the lever will result in the
helicopter rising while lowering it will cause the helicopter to sink.
At the end of the collective lever is the throttle control, explained further down the page.


As the swashplate rises or falls in response to the collective lever movement made by the pilot, so it changes the pitch of all
rotor blades at the same time and to the same degree. Because all
blades are changing pitch together, or 'collectively', the change in lift
remains constant throughout every full rotation of the blades.
Therefore, there is no tendency for the helicopter to change its
existing direction other than straight up or down.


The illustrations below show the effect of raising the collective
lever on the swashplate and rotor blades. The connecting rods run from
the swashplate to the leading edge of the rotor blades; as the plate
rises or falls, so all blades are tilted exactly the same way and
amount.
Of course, real rotor head systems are far more complicated than this picture shows, but the basics are the same.

Cyclic pitch control

The cyclic control is made by moving the control stick that rises up
from the cockpit floor between the pilot's knees, and can be moved in
all directions other than up and down.


Like the collective control, these cyclic stick movements correspond
to the directional movement of the helicopter; moving the cyclic stick
forward makes the helicopter fly forwards while bringing the stick back
slows the helicopter and even makes it fly backwards. Moving the stick
to the left or right makes the helicopter roll in these directions.


The cyclic control works by tilting the swashplate and increasing the pitch angle of a rotor blade at a given point in the rotation, while decreasing the angle when the blade has moved through 180 degrees around the rotor disc.

As the pitch angle changes, so the lift generated by each blade changes
and as a result the helicopter becomes 'unbalanced' and so tips towards
whichever side is experiencing the lesser amount of lift.


The illustrations below show the effect of cyclic control
on the swashplate and rotor blades. As the swashplate is tilted, the
opposing rods move in opposite directions. The position of the rods -
and hence the pitch of the individual blades - is different at any given
point of rotation, thus generating different amounts of lift around the
rotor disc.





To understand cyclic control another way is to picture the aforementioned rotor disc,
which is the imaginary circle above the helicopter created by the
spinning blades, and to imagine a plate sat flat on top of the cyclic
stick. As the stick is leaned over in any direction, so the angle
of the plate changes very slightly. This change of angle corresponds
directly to what is happening to the rotor disc at the same time i.e. the side of the plate that is higher represents the side of the rotor disc generating more lift.

Above: the approximate layout of helicopter controls in relation to the pilot's seat.

Rotational (yaw) control

At the very rear of the helicopter's tail boom is the tail rotor
- a vertically mounted rotor consisting of two or more blades, very
similar to an airplane propeller. This tail rotor is used to control the
yaw, or rotation, of the helicopter (i.e. which way the nose is pointing) and to explain this we first need to understand torque.


Torque is a natural force caused by any turning object and in a
helicopter it is caused by the engine turning the main rotor blades;
when the blades are spinning then the natural reaction to that
is for the fuselage of the helicopter to start spinning in the opposite
direction to the rotors. If this torque isn't controlled, the helicopter
would just spin round hopelessly!


So to beat the reaction of the torque, the tail rotor is used and is
connected by gears and a shaft to the main rotor so that it turns
whenever the main rotor is spinning.


As the tail rotor spins it generates thrust in
exactly the same way as an airplane propeller does, the difference being
that the helicopter tail rotor thrust is perpendicular to the fuselage.
This sideways flow of air prevents the helicopter fuselage from trying
to spin against the main rotor, and the pitch angle of the tail rotor
blades can be changed by the pilot to control the amount of thrust
produced.





Increasing the pitch angle of the tail rotor blades will increase the
sideways thrust, which in turn will push the helicopter round in the
same direction as the main rotor blades. Decreasing the pitch angle
decreases the amount of sideways thrust and so the natural torque takes
over, letting the helicopter rotate in the opposite direction to the
main rotors.
The pilot controls the pitch angle of the tail rotor
blades by two pedals at his feet, in exactly the same way as rudder
movement is controlled in an airplane.

NOTAR (NO TAil Rotor) is an alternative method of yaw control on some helicopters.

Instead of a tail rotor to generate sideways thrust, low pressure air
(created by a large fan in front of the tail boom) is expelled from
narrow slots at the rear (side) of the boom. The slots are opened and
closed by the pilot's pedals in the same way as tail rotor pitch is
controlled.


The amount of air expelled effects the air pressure around the tail
boom and the boom is 'pulled or pushed' one direction or the other, in
response to the varying pressure and the natural torque being generated
by the spinning main rotors. A natural effect (known as the Coanda Effect) involving air movement in relation to solid objects helps make the sideways movement of the tail boom happen.


NOTAR helicopters respond to yaw control in exactly the same way as
tail rotor helicopters do and have a big safety advantage - tail rotors
can be very hazardous while operating on or close to the ground, and in
flight a failing tail rotor can easily result in a crash. In addition to
that, NOTAR helis have a quieter operating noise level.

Throttle control

The throttle control is typically a 'twist-grip' on
the end of the collective lever and is linked directly to the movement
of the lever so that engine RPM is always correct at any given
collective pitch setting. Because the cyclic and collective pitch
control determines the movement of the helicopter, the engine RPM does
not need to be adjusted like an airplane engine does. So during normal
flying constant engine speed (RPM) is maintained and the pilot only
needs to 'fine tune' the throttle settings when necessary.
There
is, however, a direct correlation between engine power and yaw control
in a helicopter - faster spinning main rotor blades generate more
torque, so greater pitch is needed in the tail rotor blades to generate
more thrust.

It's worth noting that each separate control of a
helicopter is easy to understand and operate; the difficulty comes in
using all controls together, where the co-ordination has to be perfect!
Moving one control drastically effects the other controls and so they
too have to be moved to compensate.
This continuous correction of
all controls together is what makes flying a helicopter so intense.
Indeed, as a helicopter pilot once said to me... "You don't fly a helicopter, you just stop it from crashing"!

RC airplane controls

RC airplane controls

http://rc-avti.si/sl/http://rc-avti.si/sl/

Getting a firm understanding of rc airplane controls.


The number of controls necessary or required differs between planes;
the simplest rc airplanes will have just one single control while the
more complex planes may have five, six or more. Your 'average' rc plane
will have three or four controls, this is by far the most common number.


Incidentally, if you're completely new to the radio control flying
hobby, a controllable function of any rc model is referred to as a channel so an rc airplane with control to, say, four functions will be called a 4 channel plane, sometimes abbreviated to just 4 ch.

RC airplane controls are, of course, the same as those
found on real airplanes and they control the model in exactly the same
way.

The four primary controls of an rc airplane are throttle, elevator, ailerons and rudder. The elevator, ailerons and rudder are known as control surfaces and the picture below shows where these main controls are located on a fairly typical 4 channel rc 'sport' airplane....

Above: location of ailerons, elevators and rudder on an rc airplane.

Which controls do what?

Now you know where the primary rc plane controls are located, let's take a look at each one...

Throttle

Throttle controls the speed of the engine and hence how fast or slow the propeller turns.

On a glow plug (or petrol) rc airplane engine the throttle works the
same as any internal combustion engine throttle, by changing the amount
of fuel and air that enters the combustion chamber of the engine. The
carburettor is operated by a single servo connected to the venturi of
the carb, which opens and closes (thus changing the fuel/air mixture) in
response to your throttle stick movements on the transmitter.


On an electric rc airplane the throttle is usually referred to as motor power rather than throttle. Very basic electric rc planes (i.e. toy ones) might not have proportional control to motor power but just a simple on/off switch instead.
Electric airplanes that do have control to motor power have an electronic speed control, or ESC, that controls power to the motor in direct response to your Tx stick movements.


In the air throttle/motor power not only controls the forward speed
of the airplane but also, more importantly, the rate of climb and
descent, because different amounts of lift are
generated at different airspeeds. For example, if your landing approach
path is too low you can make the airplane rise slightly without changing
speed much, simply by opening the throttle instead of using up
elevator. Conversely, closing the throttle will cause the airplane to
sink before the speed reduces.


Using throttle/motor power in this way is the correct way to fly your rc airplane, but many pilots use the elevator to control altitude and rates of climb and descent.

Elevators

The elevators are the hinged section of the tailplane, or horizontal
stabiliser, at the very rear of the airplane and are the single most
important control surface.
Elevators control the horizontal pitch attitude of the airplane, in other words whether the nose of the plane points upwards or downwards.


When elevators are in the up position (upward deflection) the nose of
the airplane is forced to point upwards, and with the elevators
deflected downwards then the nose is forced downwards. This resulting
nose up/nose down pitch attitude comes about as the upward/downward
deflection of the elevators changes the amount of down force being
generated by the tailplane.
It's worth noting that a plane can
still fly level, or even be descending, with a very nose-up attitude but
a nose-down pitch attitude will almost always result in the plane
entering a dive, thanks to our friend gravity!
Elevators directly effect the plane's airspeed more than the need to climb or dive.





Elevators should be used in conjunction with rudder and/or ailerons when making a turn.

Ailerons

Not all rc airplane controls include ailerons, in fact the majority
of 3 channel radio control airplanes use rudder instead. But where
fitted, ailerons control the roll of the airplane about its longitudinal axis (imagine a straight line running through the centre of the fuselage, from nose to tail).


Ailerons work in pairs and are found on the trailing (rear) edge of the wing, and they work opposite to each other i.e. when one aileron moves up, the other one moves down and vice versa.





Ailerons work by changing the amount of lift generation
over the wing. As an aileron moves upwards so it disrupts the smooth
airflow over the wing surface and so lift is reduced slightly on that
wing. Over on the other wing the aileron moves downwards and increases
lift slightly. As a result, the airplane tilts and hence rolls towards
the side that's experiencing less lift.


When up elevator is applied at the same time as ailerons, the
airplane is pulled round in to a banked turn; the ailerons cause the
plane to roll and the up elevator causes the nose to pitch round in that
direction.
Ailerons are used in all aerobatic maneuvers that involve a rolling motion.

Rudder

The rudder is the hinged section of the fin, or vertical stabiliser, at the rear of the airplane.
It's used for directional control by changing the yaw of the airplane and works in the correct sense i.e. moving the rudder to the left causes the airplane to turn left and vice versa.





Applying rudder makes the nose of the airplane point to the left or
right, but rudder alone does not make the airplane roll like ailerons
do. It's actually the dihedral, or the upward 'V' angle
of the wing when viewed from the front, that makes the plane roll when
rudder is applied; a plane with very little or no dihedral will have a
much flatter turn when rudder is applied.


Rudder is also very important on the ground, it's the one control
that will keep your rc airplane tracking straight during a take off run
or landing roll if your plane isn't fitted with a steerable nose or tail
wheel.

Other RC airplane controls

Other important controls found on more complex rc airplanes include flaps and retractable landing gear, or 'retracts'.


Flaps are located on the trailing edge of each wing,
between the aileron and fuselage. They're used to generate more lift at
slower flying speeds and, at greater deflection, to slow the airplane
down close to landing by causing excessive drag.
Unlike ailerons,
flaps are connected in such a way that they both drop exactly the same
amount together so as not to upset the roll attitude of the plane when
they are deployed.


Flaps are operated with a toggle switch or rotating dial on the
transmitter. A dial is the better option because this allows the pilot
to use as little or as much flap as he wants, according to the
situation. Flaps operated by a single position (on/off) toggle switch
will be all or nothing.


When a lesser amount of flap is used it's quite common for the
airplane to pitch upwards as soon as the flaps are lowered, this is a
result of the extra lift being generated and the pilot needs to be aware
of this happening before he activates the flaps.

Retractable landing gear (undercarriage) is landing gear that folds away into the airplane's wings or fuselage once the plane has taken off.

Retracts are often used on larger rc airplanes, particularly scale
models where the real airplane has retractable undercarriage. Larger
non-scale airplanes can also have retracts, particularly competition rc
airplanes where it's necessary to reduce the amount of drag on the plane
in the air. Obviously an airplane with no landing gear hanging below it
experiences a lot less drag than one with.





Retracts can be operated mechanically by a servo, driven by
compressed air or more recently electric worm-drive. The retraction of
the landing gear is operated by the flicking of a single switch on the
transmitter, typically either on the 5th or 6th channel.

Control surface mixing

Some rc airplanes are designed in such a way that they cannot have
separate ailerons and elevators - delta-wing planes, for example. When
this is the case control surface 'mixing' is necessary and this is only
possible on computerised rc radios that offer a mixing capability.


When elevators and ailerons are combined together, or mixed, they become elevons. They look just like elevators but move together, as elevators do, and individually, as ailerons do. In short, one pair of elevons does the job of elevators and ailerons.
Flaperons
are control surfaces that mix the actions of ailerons with flaps. In
other words, one pair of control surfaces along the trailing edge of the
wing take on the job of aileron control and flap control, when needed.
Spoilerons
are, in effect, the inverted version of flaperons. Spoilers are often
found on large rc gliders and operate by the control surfaces moving upwards
as opposed to flaps that drop down. When spoilerons are deflected, the
amount of lift is drastically reduced and so the glider's rate of
descent quickly increases, enabling the pilot to land it in a smaller
space.


There are other types of rc airplane control mixing too, but those
listed above are by far the most common that you'll encounter.


Channel mixing is another type of mixing supported
by most modern computer radios. I this case two separate channels can be
mixed to operate together.
A common example of channel mixing is
an aileron and rudder mix; a small amount of rudder is automatically
applied when you operate the ailerons. The purpose of this is to produce
a cleaner turn and can prevent the effects of adverse yaw, a common situation whereby the tail drops during a turn due to increased drag over the higher wing.

The Good old Days –The Birth of RC

The Good old Days –The Birth of RC

RC-AVTI / RC-SVET



The very First example of radio control was demonstrated in New York
City in 1898. Its inventor—Nikola Tesla—was a 43-year-old immigrant who
was duly awarded U.S. Patent no. 613,809 on November 8, 1898. It was
only one of 113 U.S. patents that this prolific genius received during
his lifetime. Many electrical engineers and historians regard his basic
inventions as the foundation of the 20th century as we know it. In the
decades that followed, the military and its suppliers attempted to
implement Tesla’s work in various R/C projects—including boats and
aircraft—without very much fanfare.


 


By the middle of the 1930s, miniature airplanes were just beginning
to be powered by very small gasoline engines. An R/C contest event was
even scheduled for the 1936 model aircraft Nationals in Detroit. It was a
little premature; not one entrant showed up! The following year
however, must be regarded as the true beginning of R/C.


R/C PIONEERS


 


Several men who were active in amateur radio became interested in the
possibility of controlling model planes by radio. Two of these early
pioneers were Ross Hull and Clinton DeSoto. Both were officials of the
American Radio Relay League (ARRL), which is the governing body of ham
radio operators. Hull was a very gifted radio designer whose
achievements include the discovery and eventual explanation of the
tropospheric bending of VHF radio waves. Since his youth in Australia,
Hull also happened to be an avid modeler. Hull and his associate DeSoto
successfully built and flew several large R/C gliders in the first
public demonstration of controlled flights. Their sailplanes made more
than 100 flights. (See the January and August ’38 issues of Model
Airplane News). Tragically, Hull died one year later in 1939 when he
accidentally contacted 6,000 volts while he was working on an early
television receiver. DeSoto died a decade later.


 


COMPETITIVE FLIGHT


The 1937 Nationals R/C event attracted six entrants: Walter Good,
Elmer Wasman, Chester Lanzo, Leo Weiss, Patrick Sweeney and B. Shiffman.
Lanzo won with the lightest (6 pounds) and the simplest model plane,
although his flight was a bit erratic and lasted only several minutes.
Sweeney and Wasman both had extremely short (5-second) flights when
their aircraft took off, climbed steeply, stalled and crashed. Sweeney,
however, had the distinction of being the first person to attempt an R/C
flight in a national contest. The other three entrants weren’t able to
make any flights at all.


 


BIRTH OF THE REED


One of them—Weiss—was an 18-year-old aeronautical engineering student
who had constructed a very large, 14-foot-wingspan RC model. He and an
electrical engineering student—Jon Lopus—had devised a very
sophisticated, innovative RC system consisting of six tuned reeds that
reacted to audio tones. The reed-control system became widely accepted
in the 1950s. During the 1937 Nationals, however, Weiss wasn’t able to
start his plane’s Ferguson twin-cylinder engine. He went on to
successfully operate an avionics manufacturing company.


 


R/C EVOLVES


The 1938 Nationals were once again hosted by the “Motor City.” Although the R/C
entry list had grown to 26 entrants, only five fliers showed up on the
field. One of the newcomers was DeSoto, who entered a 14-footwingspan,
25-pound, stand-off-scale model of a Piper Cub that was powered by a
Forster twin-cylinder engine. Each of the four separate receivers on
board used a gas-filled Raytheon RK-62 tube in a super regenerative
circuit to activate its own sigma relay. His plane placed second, but it
isn’t clear whether or not it actually flew. Oddly enough, these first
contests required only that contestants demonstrate their R/C systems in
a static position on the ground to win a runner-up award.


 


Walter Good was the only contestant who attempted a controlled flight
in the face of the 20mph winds. Even though it ended in a crack-up,
Walt was awarded first place. A truly convincing demonstration of R/C
flight by a powered miniature aircraft would have to wait until the
following year. Eleven R/C fliers showed up at the 1939 Nationals at the
Detroit Wayne County airport. For the first time, a 100-point system
was adopted by the judges. Points were given for craftsmanship, actual
R/C operation in a static preflight mode on the ground and a variety of
flight maneuvers.


GOOD FLIERS


 


That was a rewarding year for Walter and William Good—23-year-old
twins from Kalamazoo, MI. Bill was a licensed ham-radio operator with
the call letters W81FD. Their aircraft—named K-G—was a slightly
modified, high-wing monoplane.


(See the K-G story in the January ’91 issue of Model Airplane News.)
This first stable gas model was designed by a former editor of Model Airplane News—Charles Hampson Grant.


Their radio and control mechanisms were the essence of simplicity. At
a time when all of their competitor’s planes carried receivers with 3-
and 4-tube circuits, the Good brothers’ radio receiver was a one tube
affair with a minimum of electrical components. Their homemade relay was
so sensitive that it could be activated by a current change of 1/2
milliamp! They also designed and made their 1 -ounce, rubber-band
powered escapement mechanism. Before going to the Nationals in 1939, the
two brothers had accumulated over 60 controlled flights in southern
Michigan. Their diligent efforts paid off with a first-place score of 89
points; the second-place winner scored only 11 points. The Good
brothers repeated their first place win in the 1940 Nationals and once
more after the end of WW II, in 1947.


 


Their historic R/C model airplane, which they affectionately named
the “Guff,” was presented to the National Air and Space Museum in
Washington, D.C., in May, 1960, where it can be seen today. Both
brothers continued their education and subsequently earned doctorates in
physics. After pursuing careers in electronics research and teaching,
they retired, but they’re still very active in electronics. Walt lives
in Florida, and Bill resides in upstate New York. They communicate
constantly with each other using their ham radios.


 


JOSEPH RASPANTE


No story on the early days of R/C would be complete without
recognizing the work of Joseph Raspante. Unlike most of the early
pioneers of R/C, who were basically model airplane builders teamed up
with ham-radio specialists, Joe Raspante was a superb designer and
builder of early gas models as well as a competent electronic
technician. His R/C system was unique in that he used a telephone dial
to select various control functions. He placed second in the 1939 R/C
Nationals and third in the 1940 event. Raspante was generous, and he
shared his knowledge with young builders in years that followed. Walter
Good remembers that when thieves stole his brother’s R/C transmitter
from their hotel the day before the 1940 Nationals, Raspante offered the
use of his own transmitter. This gesture was especially meaningful,
because the Good brothers had defeated him in the 1939 Nationals.
Raspante finally won the first place he yearned for at the 1946 NY Daily
Mirror contest at Grumman airfield. It was my privilege to see him fly
there. With the advent of the transistor and the integrated
microcircuits, today’s R/C builder hardly has any of the frustrations of
the early pioneers.


 


In retrospect, however, we see that most of the pioneer’s dedicated
efforts were largely foiled by overly complex electrical designs. But
without their perseverance, I doubt that R/C flight would have
progressed as quickly to where it is today.


Text & Images by Frank Gudaitis

Opozorila za uporabo LiPo akumulatorjev

Opozorila za uporabo LiPo akumulatorjev



 http://rc-avti.si/sl/http://rc-avti.si/sl/

P R O S I M O  U P O Š T E V A J T E:


Akumulatorji nimajo garancije, saj ne moremo spremljati kaj se dogaja z akumulatorji, ko jih odpremimo.




Nikoli ne odlagajte akumulatorja v bližino lahko vnetljivih materialov.
Akumulatorja ali posameznih členov ne razstavljajte ali spreminjajte. Ne predirajte ovoja posameznih členov.
Nikoli
ne polnite ali praznite s prevelikimi tokovi, dovoljena je uporaba
izključno samo namenskih polnilnikov za LiPo akumulatorje!
Ne izpostavljajte akumulatorja odprtemu ognju in električnemu iskrenju.
Akumulator hranite  pri napetosti 3,8V/člen. Izogibajte se nepotrebnem cikliranju.


Izjava o omejitvi odgovornosti: MRU d.o.o. ne
prevzema odgovornosti za škodo zaradi napačne uporabe ali vzdrževanja,
počenih ali uničenih ohišij, za  zlorabe in za nesreče zaradi
neupoštevanja navodil in opozoril. MRU d.o.o. ne prevzema odgovornosti
za poškodbe,  izgube, stroške, škode, ki bi nastopile neposredno ali
posredno v povezavi s tem izdelkom.

• 
  Vedno polnite akumulatorje s primernim LiPo polnilnikom. Nikoli ne polnite LiPo akumulatorje s polnilniki, ki so zasnovani samo za NiCd, NiMH ali druge tipe akumulatorjev!
  
  
  
• 
  Nikoli ne pustite LiPo akumulatorja med polnjenjem brez nadzora.
  
  
  
• 
  Akumulatorjev ni dovoljeno izdati osebam, mlajšim od 15 let, ki so brez nadzora.
  
  
  
• 
  Nikoli ne prenapolnite LiPo akumulatorja! Maksimalna napetost napetost znaša 4,20V/člen.
  
  
  
• 
  Med polnjenjem akumulator postavite na negorljivo podlago.
  
  
  
• 
  Med polnjenjem naj bo akumulator v LiPo zaščitni vreči.
  
  
  
• 
  Vedno bodite pozorni, da se akumulator ne pregreje. Temperatura nad 60°C je za akumulator škodljiva in lahko se zgodi, da se akumulator vname.
  
  
  
• 
  Nikoli ne odlagajte akumulatorjev v bližino lahko vnetljivih materialov kot so papir, plastika, tepih, usnje ali les.
  
  
  
• 
  Nikoli ne pustite akumulatorja brez nadzora v vašem avtomobilu ali v vašem modelu.
  
  
  
• 
  Nikoli ne izpraznite akumulatorja pod 2.80 V/člen pod obremenitvijo oziroma pod 3.6V/člen v neobremenjenem stanju sicer ga lahko trajno poškodujete.
  
  
  
• 
  Nikoli ne izpostavljajte akumulatorja vodi ali vlažnim pogojem.
  
  
  
• 
  Nikoli ne odlagajte akumulatorjev blizu ognja ali ogrevalnih naprav.
  
  
  
• 
  Nikoli ne spajajate posameznih LiPo členov ali paketov skupaj z ostalimi členi ali paketi.
  
  
  
• 
  Shranjujte akumulatorje v varnem prostoru, izven dosega otrok.
  
  
  
• 
  Vedno odstranite akumulator, v kolikor je model pristal
  zasilno oziroma se je poškodoval. S skrajno natančnostjo preglejte
  akumulator in priključke. Pozor: akumulatorji so lahko vroči!
  
  
  
• 
  Ne dovolite, da bi elektrolit iz členov prišel v stik z očmi ali kožo. Temeljito izperite izpostavljene dele z vodo.
  
  
  
• 
  Ne zamenjujte priključnih kablov na akumulatorju. Zamenjave priključkov ali krajšanja kablov se lotite le, v kolikor ste vešči spajkanja.
  
  
  
• 
  Vedno preverite stanje akumulatorjev pred polnjenjem in uporabo.
  
  
  
• 
  Izogibajte se kratkim stikom. Kratki stiki škodujejo akumulatorju in lahko povzročijo požar.
  
  
  
• 
  Neposredno se ne dotikajte predrtih oziroma poškodovanih akumulatorjev.
  
  
  
• 
  Ne polnite akumulatorjev izven temperaturnega območja od 0°-45°C (priporočena temperatura polnjenja in praznenja 25°-35°C)
  
  
  
• 
  

Nastavitev vplinjača

Nastavitev vplinjača

 http://rc-avti.si/sl/



Na metanol motorčkih za modele avtomobilov imamo 3 igle nekateri 4(4-ta
igla(igla za srednje obrate oz MSN-medium speed needle)je dokaj redka in
sicer se nahaja na nasprotni strani igle za nizke obrate LSN-low speed
nedle).Te igle ne tikamo oz pustimo na tovarniških nastavitvah..

Torej
1.Igla za prosti tek(idle needle)
2.Igla za visoke obrate(HSN-high speed needle)
3.Igla za nizke obrate(LSN-low speed needle)
4.Igla za srednje obrate((MSN-medium speed needle)velikokrat je ni,če je jo pustimo na tovarniških nastavitvah).


Z
iglo za prosti tek nastavljamo obrate prostega teka motorja pravzaprav z
njo samo nastavimo do kam se zapre batek v vplinjaču, če batek gre do
konca prekine dovod zraka in motor se ugasne, pri avto modelarjih bi se
brez te igle to zgodilo ob vsakem zaviranju saj si ponavadi motor ter
zavore delita servomotor(letalski modelarji lahko vozijo brez oz če ga
vzamejo ven/odvijejo dovolj, lahko motor ugasnejo z komando). Ta batek
se ob dodajanju plina odpira, ter ob spuščanju plina zapira(to je vidno
če se sname cev zračnega filtra ter pogleda v to odprtino). Začetna
nastavitev je nekje 1mm luknja predno batek popolnoma zapre odprtino



Z
iglo za visoke obrate nastavljamo dotok goriva motorju nekje od
polovice pa do polnega plina. Z iglo za nizke obrate pa od prostega teka
ter do nekje polovice oz dokler ne prevzame igla za visoke obrate.

Z
privijanjem oz vrtenjem v smeri urinega kazalca igle zapiramo(manjšamo
dotok goriva oz motor nastavljamo na bolj revno mešanico), z odvijanjem
oz v obratni smeri urinega kazalca igle odpiramo(povečujemo dotok goriva
oz motor nastavljamo na bolj bogato).To vršimo v malih korakih
maksimalno 1/8 če pogledamo na uro so to približno 7min koraki, še bolje
1/12 kar je 5min na uri.



Pomembno
je tudi vedeti tovarniške nastavitve vplinjača, saj vemo da na teh
nastavitvah motor mora vžgati(so pa to nastavitve za bogato nastavljen
motor).

Sedaj ko vemo kaj katera igla dela ter kje se nahajajo
lahko pričnemo z finim nastavljanjem. Pravzaprav to počnemo kar
dostikrat saj so ti motorji občutljivi na vremenske razlike toplo/mrzlo
tudi nadmorska višina igra vlogo, potem ob raznih spremembah na motorju
kot so menjava izpuha, zračnega filtra, goriva, svečke na koncu tudi od
tega po kakšnem terenu ter kako vozimo(npr nastavitev za progo je
ponavadi drugačna kot pa za dirkanje po parkirišču gor in dol). Iz tega
tudi izhaja razlog zakaj ne moremo podati neke univerzalne nastavitve ki
bi bila vedno ter za vsakogar dobra.Na hitro še en plonkec ob prehodu
iz toplega na hladnejše vreme je potrebno nastaviti na bogato.Povečini
je največkrat treba nastavljati iglo za visoke obrate.

Razlika
med res dobro nastavljenim ter zanič motorjem je majhna zato po pameti
malo po malo, ravno tako od prebogate nastavitve še nobeden motor ni bil
zanič(zato je bolje bolj bogat kot pa prerevno nastavljen). Ravno tako
mora motor v vseh režimih plina kaditi rahlo modro v nasprotnem je
nastavljen prerevno.

Vedno začnemo z tovarniškimi
nastavitvami motorja, če imamo vmes težave igle povrnemo na tovarniške
nastavitve ter pričnemo od tam(nastavljanje motorja brez te informacije
zna biti precej težavno).Preden začnemo fino nastavljati motor naj bo ta
dobro utečen. Ravno tako mora biti ogret na delovno temperaturo.
Iglo za prosti tek nastavimo kot na sliki zgoraj ostali dve igli pa na tovarniške.


Do tukaj so bile splošne informacije oz osnove kje je kaj ter kaj počne katera stvar.

Tukaj
bom napisal kako sem motor nastavljal jaz(postopek sem pobral čez lužo
od nekega tunerja teh motorčkov), saj obstaja več načinov, zadnje čase
je popularno nastavljanje z ir oz brezkontaktnim termometrom(avto
peljemo z polnim plinom, nato pripeljemo z polnim do sebe ter hitro
izmerimo temperaturo v predelu svečke, nato iglo za visoke privijamo
dokler po vožnji nimamo želene temperature približno 120stopinj) to ima
svoje prednosti ter slabosti ena je da pozimi motor kljub ustrezni
temperaturi lahko deluje prerevno(okoliški zrak ga dosti bolj ohlaja in
tako lahko dobimo napačne informacije).

Najprej nastavljamo iglo za visoke obrate(ravno obratno kot pri bencinskih modelih)
Sam
sem naredil par dolžin tam kjer vozim z polnim plinom ter ob spustu
plina na komandi poslušal kako padejo obrati na obrate prostega teka.
Če
obrati padejo lepo brez obotavljanja tik pred obrati prostega teka je
igla za visoke obrate nastavljena bogato ali optimalno, zato iglo
privijem za 1/12 obrata in naredim vožnjo z polnim plinom to ponavljam
dokler ob spustu plina obrati padejo ter se tik pred obrati prostega
teka še malo zadržijo ter padejo na obrate prostega teka, na tej točki
iglo za visoke obrate odvijem za 1/12 obrata.

Logika za tem je
takšna da če je igla za visoke obrate nastavljena prerevno in ko
spustimo plin, motor deluje prerevno in malenkost traja da igla za nizke
obrate prevzame delovanje.

Če se zgodi nasprotno da obrati
lepo padejo na obrate prostega teka ter se nato povzpnejo je igla za
nizke obrate nastavljena prerevno.Za iglo za nizke obrate obstaja tudi
trik ki nam pove kako je nastavljena in sicer stisnemo cevko za dovod
goriva ter gledamo v kolikšnem času motor ugasne.
-če motor ugasne takoj je igla nastavljena revno
-če motorju narastejo obrati ter ugasne nekje med 3-4s je igla nastavljen dobro
-če motorju narastejo obrati ter ugasne po pretečenih 4s je igla nastavljena prebogato

V vseh režimih pa opazujemo da motor kadi lepo modro..