Headlock vs rate gyro setting

magyarbacsi · Extreme 3D Joined: 04 Aug 2011 Posts: 99 Location: seattle

Pretty much finished my HK 450 TT PRO using Turnigy 401B gyro. I built a test stand, basically a lazy suzan , but with a center bearing instead and is more sensitive. I secured the copter onto it an fired it up to half throttle. The gyro gear switch is set at 35% and rate at 65%. When I first start the motor, soft mode, the thing twirls like a dancer till I get up to speed and switch on HH setting where it holds still. Then on rate mode it spins until I counter it with quite a bit of counter rudder and have to hold it with the rudder. If I let the rudder back to nutral, it spins like heck. Does not the gyro ste the tail pitch automatically on rate to counter then head speed torque, or am I not set up right. I'm a newbie and have not flown a 6 ch cp yet. In the learning stage, but have watched buku videos by finless and understand the basics, I think.

Is that normal or should rate mode hold it steady also without having to constantly hold rudder to counter the torque?
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KCF

solentlife · Posted: Thu Nov 03, 2011 1:41 pm Post subject:

Sorry but there are a few wrong things here ...

a) The heli is not on a fixed base such as ground which provides friction on skids on spin-up...
b) Heli should be stable on ground / base when powered up. Gyro should be in HH mode on TX ... this then aligns it to heli's orientation on ground.
c) Rate mode is lower or negative numbers in Tx menu ... HH is higher or +ve numbers in Tx menu.

Reading your post ... I think you either have terms wrong or misunderstood ...

Rate Mode does not hold a heading as Heading Hold does. HH will try to return to a heading that it is aligned to until you input rudder / tail command to alter that ... it will then accept new heading as it's reference.
Rate Mode will steady down tail movements but does not hold an exact heading for you ...

Here's a good link to read : http://www.rchelicopterfun.com/heading-hold-gyro.html

Post on another forum ....
"Rate mode means that the gyro dampens the rate of unwanted changes in yaw. Ie, if the helicopter is hovering in a cross wind the tail will move, the gyro will correct a bit and return to center so that the rate of change is controllable by the pilot but after a few of these cycles the helicopter will be pointing into the wind.

Same helicopter with a heading hold gyro, the wind will blow the tail and the gyro will correct, and move a little more to bring it back where it was if need be, it will also hold that correction until something changes (the wind gets stronger the gyro will correct more, or gets weaker it will correct less)

In rate mode in forward flight the tail will weathervane and follow the nose. In heading hold if you turn the tail will stay put till you give a bit of rudder to coordinate the turn.

In rate mode you can't fly backwards, it simply can't cope with it. "

I don't totally agree with his comment about flying backwards ... I have videos of 1980's heli's flying backwards well enough with then current rate gyros and without gyros at all !!

So to recap ..... Switch on TX .. select HH mode ... power up Heli on solid immovable ground. Let Gyro settle - you'll see the tail rotor slider twitch / move to centre position after all the beeps.
Now when spinning up ... slow for first turns to avoid the wobble and tail moving round 20 - 40 degrees (due to inertia of the head being forced to turn from rest). Once rotors are turning and heli is sitting steady ... bring her up reasonably quick to just before lift off throttle so she's light on skids ... carefully watch tendency of the heli ... is she tipping fwd, back or to the side ? Trim can be made now to correct this ... NOTE : it is normal for a heli to slide, tend to left due to the effects of tail vs head rotors so when steady in a hover - the heli will have a very slight right lean ... barely noticeable, but there. So as she lifts you'll give a hint of right cyclic to keep her lifting straight up instead of the left drift we all have at times !!

My opinion is that rate mode on Gyro can be ignored for most flying and until you really want to throw the heli around.... HH is the mode to stick with.
_________________
If you don't crash - you ain't flying !
Fast learning to be 450 Heli Repair specialist !
Have : 2ch Bumblebee,
Co-Ax Syma S006 Alloy Shark
2x Clone 450 SE V2
+ fixed wing stuff ...
Returning to RC after 20 odd yrs away .. Ex Display flyer.

magyarbacsi · Extreme 3D Joined: 04 Aug 2011 Posts: 99 Location: seattle

Thanx solentlife. So in rate mode flying do you always have to correct rudder for the torque or can you mix the tail rotor pitch as in revo mix to match the head rotor torque and let the rudder stick to nutral with minimal input to fly straight. Finless states to not use revo mix with gyro? I guess I was comparing it to my 180D where I can hover with very little rudder input until I decide to change directions. I was watching a youtube demo where the person was showing how a HH gyro holds the course on a turn table and I was tryng to duplicate that. And on the turn table my 450 did hold steady on the HH setting. I was also able to trim the gain to where the tail quit hunting.

I guess once in the air it will act totally different and will have to change settings. But I'm not there yet. Have a few more adjustments and some ground practice to do.
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KCF

solentlife · Posted: Fri Nov 04, 2011 1:05 am Post subject:

I'm no expert in this and I'm sure others here are better on this than I ....

But as regards REVO ... forget it. REVO is a hangover from old days of Piezo Gyros etc. where all they did was damping down tail movement. REVO was used to try and counter increase/decrease torque reaction as you altered throttle / collective.

If you try and use with a modern Gyro - you will end up with a mess !

Remember that once you get really good at Heli ... you will be flicking the Idle Up switch to do aerobatics ... now many set-ups have HH in normal mode, Rate mode with Idle-up ........ so having REVO mix will be a real party destroyer ... If you go the ultra modern way of HH in both Normal and Idle Up .... then REVO is doubly unwelcome.

Maybe this comment can be made in good faith ... forget fancy tables etc. You need to build the courage to actually get out there and do the job.

Rate Mode ? Why would you want to even think about using Rate Mode ?
Like REVO - it's old hat ...

Basically ... set swash level at all ranges, check and set pitch, have Normal mode selected ............ fly.
_________________
If you don't crash - you ain't flying !
Fast learning to be 450 Heli Repair specialist !
Have : 2ch Bumblebee,
Co-Ax Syma S006 Alloy Shark
2x Clone 450 SE V2
+ fixed wing stuff ...
Returning to RC after 20 odd yrs away .. Ex Display flyer.

magyarbacsi · Extreme 3D Joined: 04 Aug 2011 Posts: 99 Location: seattle

Ok, I got most of that. Now, my gear switch in the up position is HH gyro and I gave it 35% and seem to hold tail ok. What function does it perform in the down position and what value should I give it if any? My gear switch is ch 5. I think Bob stated it is the Rate mode? So I should just avoid that function?

The weather in Seattle sucks now
_________________
KCF

Crashagain · Posted: Sat Nov 05, 2011 12:07 pm Post subject:

I use rate mode only for resetting the tail after I walk to the flight line with my heli and set it down.
I will toggle the switch to reset the tail back to center before I spool up to avoid the heli trying to spin around as the head speed slowly comes up.
If you want to fly in rate mode you have to set the tail up in rate mode.
Your turn table is a good idea, I made and used one when I had a logitec 2100T on my 450.
Put the gyro in rate mode and spool up the heli and pay attention how much rudder you have to use to hole the tail still.
Now slide the rudder servo up or down the boom to move the tail in the same way you were holding it with the stick. Spool up and do it again. The goal is to get the heli's tail to not drift while in rate mode.
There is one advantage to setting up a tail in rate mode. If you had for some reason, lost HH mode in flight, you would not have to fight the rudder so much to keep tail in check.
I agree that backwards flight would not be possible in rate mode.
I am sure they did it in the old days, but not at the speeds that we can fly today. I am sure that if you went really slow and were really good with rudder inputs, you can do it. But as soon as you get up to any speed the tail would just keep blowing out on you.
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Trex 450V1...Trex 600Nitro Flybarless, Outrage Velocity 50 flybarless. Frenzy V2 50.
Crashing is just a landing that cost you money..

solentlife · Posted: Sat Nov 05, 2011 3:18 pm Post subject: Re: headlock vs rate gyro

Crashagain · Posted: Sun Nov 06, 2011 9:05 am Post subject:

Rule of thumb.
keep turning up the gain and flying untill you get the tail to wag. Once it starts to wag, then back the gain down a couple of points.
_________________
Trex 450V1...Trex 600Nitro Flybarless, Outrage Velocity 50 flybarless. Frenzy V2 50.
Crashing is just a landing that cost you money..