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Other › Explain the 4-in-1 to me..
10-08-2005 04:01 AM  12 years agoPost 1
CLSSY56

rrApprentice

Waterloo IL

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I know it has the reciever, esc, gyro and mixing board. How does the gyro work?

-Travis
HorizonRcFlyers.com

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10-08-2005 06:06 AM  12 years agoPost 2
Balance

rrApprentice

Rapid City, SD, USA

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Gyro simply senses rotation in a given axis and reports it to the proper center in the electronics package. In this case all electronics are combined into one unit and the axis we are controlling with the gyro is the yaw axis.

Two ESC's (Electronic Speed Control) control the voltage output to the individual motors: one for the main blades, the other for the tail rotor.

The proportional mixer changes the voltage output to the tail rotor motor based on collective/throttle stick position, i.e. higher stick, more throttle/pitch means more torque, therefore more tail rotor thrust needed to counter, and vice-versa when the stick is lowered. It works by essentially splitting the amount of power delivered to each motor based on the amount of power requested by the throttle stick. The amount of proportional mix is adjustable by the pilot by turning the pot on the 4in1. (Clockwise for more thrust (right yaw) and counterclockwise for less thrust.) It should be set so the tail stays relatively steady without any rudder trim or rudder input throughout the collective stick range.

The gyro senses changes in the yaw of the helicopter and counters by asking the tail rotor ESC to add or remove power from the tail rotor. Basically, the gyro and the proportional mixer work together to hold the tail steady; the mixer changes tail thrust based on the power delivered to the mains, and the gyro changes thrust based on rotation of the yaw axis to dampen sudden torque changes caused by a variety of factors, mostly subtle collective and cyclic changes made by the pilot to correct attitude and hold a particular flight pattern, i.e. hover, forward flight, etc. The gyro sensitivity is adjustable on the 4in1 by turning the gyro pot clockwise for more sensitivity and counterclockwise for less.

The third and final stage in yaw control is the anti-torque, or rudder input from the transmitter. Moving the rudder stick right or left will increase or decrease the amount of tail thrust to allow for desired yaw changes, such as a heading change in hover and coordinated turns in forward flight, or yaw corrections in any flight mode.

In full size helicopters, where there is no gyro used to help control the tail, the pilot must compensate for all torque changes by inputting the proper amount of yaw control using the anti-torque pedals. All three types of input: collective, cyclic, and anti-torque (yaw) constantly work together and against each other at the same time. Any change to one input will require a corresponding counter with the other two.

In a flying model heli, the tail would be impossible to control without help, and that is where gyros and mixing come into play. Many models/modelers choose to use heading hold gyros which are designed to not only dampen unwanted yaw, but actually hold the heading in one spot until the pilot requests a different heading with the yaw stick (right/left on the collective stick in Mode 2). This is most beneficial to 3D pilots who need the tail to stay put until they want it to move.

In other models, a non-heading-hold gyro is used, and the proportional mixing is done by programming in the transmitter. It is call revolution mixing in a Futaba system. This setup, like the 4in1 on the blade, does not necessarily hold the heading, and therefore, pilot correction of the tail will be necessary.

In all systems, the amount of gyro gain is set based on pilot preference, and in most cases it is most desirable to set the sensitivity as high as possible to hold the tail steady without wagging or hunting. With everything set right for calm conditions, a model may still be found to wag the tail in a cross wind. This happens because the heli is trying to "weathervane" into the wind, and the gyro is fighting it. In windy conditions it is best to lower the gyro gain to eliminate the hunting. This will, of course, require more pilot input to control the tail.

As you can see, the flight of a helicopter, and the specifics of set-up of your model are full of compromise. You just have to find the best set-up for your skill and flying style.

Hope this answers your question.

Good flying!

Barry

FOR SALE Kyosho Nexus .30 and Futaba 8UHF lots of extras

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10-08-2005 10:12 AM  12 years agoPost 3
B52fixer

rrApprentice

Oklahoma City,​Oklahoma, USA

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Is the Gyro HH or not? Just wondering because I am now the proud owner of a new blade!
-Andrew

Nevermind should of read closer.

A word to the wise ain't necessary. It's the stupid ones that need the advice.

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10-08-2005 01:56 PM  12 years agoPost 4
bell1684

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North Kingstown, RI​USA

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The gyro isnt HH..you need to fly it manually.

Thats half the fun of the heli IMHO

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10-08-2005 02:08 PM  12 years agoPost 5
swattley

rrVeteran

West Milford NJ

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the gyro in the blade is not a heading hold and the tail can be a challenge if you are used to flying a heli with heading hold. i fly a raptor for 6 months now and just got a blade and it takes some getting used to having to fly the tail while trying to control the rest of the heli that keeps moving in every direction. remember not to over compansate you only need very small corrections to keep the heli as steady as it can be. but once that tail spinns around that is were i get into trouble.

that last post was very good would you know how to explain how a heading hold gyro knows to stay at that heading?

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10-08-2005 02:30 PM  12 years agoPost 6
Gary Hoorn

rrKey Veteran

Annapolis Maryland​USA

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Balance,
An excellent explanation but I must add a comment:
In a flying model heli, the tail would be impossible to control without help,
A lot of us "old timers" learned to fly Helis when none of the things like computer radios, gyros etc. were available I have to admit it is much easier now and I prefer the modern way!
Gary

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10-08-2005 09:42 PM  12 years agoPost 7
Balance

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Rapid City, SD, USA

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I agree. I think it could be done, and I would like to try it when my skills advance, and I have a couple of "spares".

When I say "impossible" I mean the learning curve would be MUCH broader without gyro and tail mixing. Technology has blessed us.

BTW, I will work on my explanation for HH.

B

FOR SALE Kyosho Nexus .30 and Futaba 8UHF lots of extras

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10-10-2005 04:22 AM  12 years agoPost 8
Balance

rrApprentice

Rapid City, SD, USA

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OK, Heading Hold

We know that a gyro senses angular acceleration, or rotation on its subject axis. How it does this is topic for another discussion, but it is sufficient to say that when the gyro housing is rotated, the unit senses this and changes it into an electrical current which is read by a computer. Piezoelectric gyros of today are much more accurate and faster than the original mechanical gyros.

The capabilities of any gyro depend on its accuracy in reporting rotation and the electronics and programming that use this information.

Non-heading hold gyros, either mechanical or piezo, sense rotation and react to it. Some newer non-heading-hold gyros are more sophisticated than others, and the technology continues to advance, but they all do essentially the same thing. Newer gyros are capable of drift-free operation, despite changes in temperature and other climatic factors that used to plague older versions. Also, gyros used to do nothing more than dampen or slow down rotation, including rotation requested by the pilot as a result of stick movement. Newer versions allow for pilot rotation of the yaw-axis by telling the gyro to allow a certain rate of rotation, or angular acceleration, based on the amount of rudder stick deflection, while still controlling unwanted yaw.

Heading hold gyros use much more sophisticated mathematical algorithms to not only sense rotation and counter it, but to actually READ the amount of rotation and counter with enough input over time to return to the original position. It's not like a compass. It's more like a spring. It starts in one spot and is always going to try to return to that spot, until the pilot tells it to do something different. It is by no means perfect, but close enough that the naked eye could never tell. You could also think of it as the gyro doing exactly what you would do to correct the tail and return it to a certain postion and try to keep it there at all times. It is another step forward in taking the pilot's concentration on the tail out of the picture and allowing him to concentrate on other things.

Real world example in theory:

You are hovering in relatively calm conditions when suddenly you experience a gust of wind from the side strong enough to cause the heli to rotate 1/8 of a turn, or 45 degrees.

A non-heading hold gyro would sense the rotation as soon as it started, and immediately begin to counter. As the gust dies down, the unrequested rotation stops and the gyro stops reacting. Without any correction by the pilot, and depending on the sensitivity setting of the gyro and the power and duration of the gust, the tail could perceivably stop just about anywhere within that 45 degrees. If the sensitivity was really high, the tail could actually be overcorrected and stop somewhere on the other side, or wag quite violently through the gust.

A heading-hold gyro would do exactly the same thing, but while it is countering the forces, it is also continuously reading the number of degrees of unrequested rotation, and will not stop correcting until it gets back to zero, or where it started. If a heading hold gets knocked 45 degrees, it will counter until it reads 45 degrees in the opposite direction before it stops responding to that error.

If the pilot moves the rudder stick during all this, the gyro will allow angular acceleration equal to the relative amount of rudder stick input. In other words, if tail gets knocked 45 degrees to the left, and the pilot at the same time inputs enough left stick for enough time to stop at 45 degrees, the gyro will essentially do nothing but start to hold the tail at that new position. If, on the other hand, the pilot actually countered just enough to zero the heli, then he would double what the gyro did, and the heli would end up at 45 degrees the other direction, and the gyro would start holding the tail there.

There are pros and cons to heading hold use. HH is a huge help for 3D pilots because it locks the tail in place and waits for the pilot to request a change. This allows the pilot to pay full attention to his maneuvers. Heading hold can be a hinderance in forward flight, though, where it is desireable for the heli to weathervane into the headwind and follow a nice forward flight pattern. In FF and FFF, non-heading-hold allows for smooth, coordinated turns with a minimum of rudder input. Heading hold mode will hold the tail in the same direction throughout a turn unless the pilot inputs the right amount of rudder. There is no help from the tail fin. Without rudder stick input, the turn would end up a side-slip, because the tail wouldn't follow the heli through the turn. Some heading hold gyros allow a pilot to switch between heading hold and non-heading hold mode with a switch on the transmitter.

Keep in mind that this is just an exaggerated example, and any good gyro, HH or not, set correctly would need a pretty hefty gust of wind to get weathervaned a full 45 degrees before starting back to zero.

As you can see, the mathematics involved with heading hold are extremely complex, and the capabilities of these devices come from their programming.

Good flying!

B

FOR SALE Kyosho Nexus .30 and Futaba 8UHF lots of extras

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10-10-2005 09:46 PM  12 years agoPost 9
swattley

rrVeteran

West Milford NJ

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balance that was a great explanation and it really helped me understand how the heading hold worked. i also liked the part on forward flight without heading hold. i have not tried to turn the heading hold off during flight but always wanted to try it and see what happened. i am just starting to do forward flight now i have been doing a lot of practice with all points of hovering nose in and side facing.

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10-11-2005 04:36 AM  12 years agoPost 10
Balance

rrApprentice

Rapid City, SD, USA

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Swattley,

I am glad the explanation helped.

I'm guessing you know this already, BUT, not wanting to ASSUME anything:
If you are planning to try some FF in non-heading-hold mode, be sure to set up the heli with revo-mixing first, and start from the ground, hovering, etc. I would hate to see what happens (and be responsible for it) when you switch off the HH midflight without some prior planning.

For example:

Before I got my Blade CP, I was hovering my .30 nitro Kyosho Nexus in the backyard. I was getting quite confident and comfortable with this, and was going pretty high and pirouetting, etc. My brother was there watching. I decided to switch into idle-up 1 on the TX and check my throttle curve settings there. I accidentally switched it all the way to idle-up 2, and the heli did about a 180 pirouette in about a microsecond, and took off, out of control. I just about lost it in a neighbor's yard, but luckily I got it back into normal mode, swung it around before it disappeared out of sight, and slowly brought it back. My brother was freaking out. We both thought it was gone, and my biggest fear was the heli hitting someone. I didn't have the revo-mixing set up right in ID2 (or ID1 for that matter, either), and as soon as I hit the switch, it became completely unpredictable. I wasn't prepared.

Anyway, make sure you get the setup right on the ground before you try anything in flight. I don't want to see you wreck your bird or your head!

Good flying!

B

FOR SALE Kyosho Nexus .30 and Futaba 8UHF lots of extras

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10-11-2005 11:43 PM  12 years agoPost 11
swattley

rrVeteran

West Milford NJ

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i was going to ask some opinions at our heli club before trying anything and i did think about the revo mix because i know it is not set up yet in normal mode. i actually lifted off the ground last week in normal mode by mistake and knew right away what was wrong with the tail wagging back and forth.

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