Heading Lock Gyro

[tonybolony]

does a Heading Lock Gyro make the heli easier to fly?

[G-MRM]

Hi, in a word yes !

Once setup move the tail to where you want it and it will stay. If you don't have one or you turn it off HH to rate mode should the wind blow onto the model it will weather vain. Some may tell you that you should learn with it off so you get to use the rudder while training, I think you have lots to do already and will do you no harm to keep it on !

I do say once you can hover Ok you should try with it turned off (if you have one that will switch modes) so you get to fly in rate mode thus if you flew a new model for someone you will know what to expect.

While flying some circuits it helps to fly in rate mode then the tail will swing and follow the nose in the turns.

Most if not all RTF small models don’t have HH. Next heli you own when moving up should have one I think.

Hope that helps a little.

Martin

[swatson144]

I'm in agreement with Martin HH really helps a beginner. The main thing I see is that you really aren't equipped to setup revo mix while learning to hover. That would require a more experienced pilot, who probably would only get it close and not quite perfect.

Steve

[G-MRM]

Good point Steve, I find revo mix a pain to set up, so it's not only me then !!lol

[swatson144]

Nah you, me, and about everyone else would rather fly the tail in train doing circuits than setup revo. I used to always set it but never switched to rate mode to fly anyway. Then when I'd inhibit revo to mechanicaly center the tail I'd have to put the settings back anyway.

So now I just use rate with no revo to setup the tail at hover. I only do rate on the non HH gyros. I still have 3 of them on motorized tail micros, and find rate/revo as effective on them as HH.

Steve

[tonybolony]

Thanks I Think Im Going To Buy One

[Fireant]

To be honest, I think it better to learn in normal rate as opposed to HH. Don't get me wrong, HH is a great tool and does take some of the workload away. However, learning in normal hold makes you use the rudder and get to know how important it is. The other reason I think it's important, is the fact that when you initially setup a HH gyro, the mechanical trim is done in normal hold. I've seen too many models with badly out of trim rudders because the pilot has it set in HH. If the mechanical trim is done correctly, then there should be no need for REVO mixing.

Once you've got a feel for it in normal, then switch to HH. That's my thought's but you must make your own choice.

[G-MRM]

Ant, the question was....
does a Heading Lock Gyro make the heli easier to fly?

Answer is yes..... :) :)

However you have a point and most good HH gyros need setting up in rate mode first so once past the hovering stage try out rate mode !

Martin

[swatson144]

If the mechanical trim is done correctly, then there should be no need for REVO (http://www.rchelicoptertown.com/forum/glossary.php?do=viewglossary&term=36) mixing.



Ant no matter how it's set up you need to mix throttle to rudder in rate mode to fly. Must have been a while since you've flown in rate. Most pilots would be able to hover as long as you can keep the throttle changes very smooth. The mixer in the Xn1 does the job of revo in the RTFs. You are right though, learning to fly in rate without revo would indeed make one good at controlling the tail and very smooth on throttle. They'd both have to be controlled in conjunction "manual mix".

I also always setup the tail for center in rate (and have seldom bothered to setup revo in most of my helis) nice smooth hover on a calm day is no problem. Ah, but moving out of hover is something else completly! Once you leave hover in rate with no revo it's about 1/2 of not having a gyro at all. I once had an HLG200 which was kinda hard to get the gain set right so setting the mechanical center was easiest to just bypass the gyro with an extension and hover. I also tried gyroless flight and it was not a bunch more challenging than rate sans revo.

I think I'm a little beyond novice in yawing flight, and have lots of practise with slow traveling piros etc. I usually don't recommend setting mechanical center in rate until I know the pilot is ready to do it. To that point it's pretty dangerous for the equipment, and not really needed for the hover jockey. When they lift off and it rotates 180 because they didn't hold the tail they often freak out and crash. Which brings us to your point if they'd been flying in rate all along it wouldn't have happened. I see your point and was a subscriber of it. I have somewhere along the path changed my mind. Flying in HH gives much more practise in FF than in rate. In HH FF one has to fly the tail to keep it in train behind the nose. In rate it just weathervanes back there on it's own.

3 of my micros are rate/revo. Though I started with rate/revo on an H2 I don't recommend others go down that path. It gave me a lot of trouble and very little in return for it. Sometimes I enjoy the ease of FF without having to do more than point the nose with the rudder though.

Steve

[Fireant]

Martin. Yes, correct, I got a little sidetracked trying to make the point of not relying on the gyro to control the tail for you.

Ant no matter how it's set up you need to mix throttle to rudder in rate mode to fly

Steve, beg to differ. I learnt to fly in normal rate and I fly my scale models in it as well. I have never used revo mixing. I use HH on the P&B when doing aeros and may switch it in on the scale ships if I have to come in against a cross wind.

[swatson144]

It's cool then, your experience differs from mine. I don't know how that can work considering the way a rate gyro functions.

Steve

[estarter]

HH gyro holds the tail better.

Most of the tail drifting issue when flyin' with the motor driven tail is the battery voltage, it the batt pack has low "C" and capacity rating, the pack voltage will vary from the beginning and toward the end of the flight. In turn the tail needs some in-flight rudder trim to compensate.

[Fireant]

Steve, I can't explain it. I used to fly a lot of fixed-wing pattern aerobatics where the rudder is used extensively. This was a major benefit to me when transitioning to helicopters. As my experience is mainly with ic models, it's possible, they do not need revo mixing as much as an electric model might.

My first gyro was a CSM 180 and then I went onto the CSM400. In the instructions for this, you're told to make sure all mixing, including REVO is inhibited. Therefore, I've always setup the gyro without it. Admittedly, if the power is spooled up too quickly, the tail will kick, but I've not had a problem in flight.

When we filmed the AS350, I flew that in normal rate. As this was the first proper flight, the trim still needed some fine tuning. However, to get back to the original question, I'm with the majority.

Most of the tail drifting issue when flyin' with the motor driven tail is the battery voltage, it the batt pack has low "C" and capacity rating, the pack voltage will vary from the beginning and toward the end of the flight. In turn the tail needs some in-flight rudder trim to compensate.

This is also because the mixer dedicates the majority of the current to the main motor and controls. The importance placed on keeping the model airborne. Unfortunately the tail motor suffers as a consequence.

[swatson144]

OK Ant I looked at the manual for the 400 and can see the explaination.


The ICG400 system
The ICG400 employs a 'Yaw Rate Demand' philosophy making it a true yaw rate gyro. In this system the rudder command from the pilot is interpreted as a request to the gyro to establish the desired yaw rate. The gyro drives the tail rotor servo as needed to obtain this yaw rate. This means that the ICG400 makes full yaw rate available even at high gain settings. With this system you can use the rudder travel adjustments ('Travel Volume', 'ATV') and rudder rates facilities to set up the desired full-stick yaw rate and the gyro gain switch now becomes a 'Flight Mode Switch' for the gyro. There is no need for so called Pilot Authority Mixing - indeed you should not use pilot authority mixing with this gyro

A "yaw rate gyro" doesn't get any feedback about what the heli is doing. It only measures the angular acceleration and provides a counter to it. Once the counter thrust is given it is then at it's new 0 point

The gyro drives the tail rotor servo as needed to obtain this yaw rate.
Would imply feedback is given.

Your ICG400 seems to be like the HLG200 I mentioned earlier and is HH only. Yet it has what it calls standard mode


Mode 0 (Standard Mode)
This mode gives flying characteristics that are similar to conventional gyro systems, but it also incorporates an auto trim that compensates for small inaccuracies in the mechanical adjustment of the tail linkage, variations in engine performance, etc.


It's perhaps the auto trim that makes the difference. If you power it up and switch to mode 0, swing the tail does it go back to zero pitch on the blades like a rate gyro? or does it hold the same pitch (or increase) like a HH gyro.

It's interesting! It sounds like in mode 0 it's a "taint" Taint really a HH and taint really a rate. 8-)

Everyone elses (that I know of) rate gyro has no feed back whatsoever. It simply detects the angular velocity and supplies a countering force and where it ends is now home. Without revo to compensate for increasing and decreasing main rotor torque it'll just walk around in a circle. That makes it sound like it'll jerk around, which it is, but at like 150 times a second it seems pretty smooth.

OK in other words from the EHBG

23.6.2. Yaw rate gyros and how they work
For a yaw rate gyro, the functions are controlled by the following devices:
• Counter main rotor torque - transmitter revo mixing
• Turn (yaw) the helicopter - rudder stick
• Stabilize yaw - yaw rate gyro
A yaw rate gyro is a very simple device. It only senses the turn rate (angular acceleration) and
it cannot sense the absolute orientation of the helicopter. In technical terms, it "dampens" the
tail movement.
Imagine you are blindfolded, and are standing on a frozen lake wearing smooth shoes. A person
will try to turn you, and you are only allowed to resist the turning force by digging in your
shoes into the smooth slippery ice. Basically, you cannot resist the turning force very
much,and once you have been turned, you do not know the original orientation.
This is very much like a yaw rate gyro.
Therefore, a yaw rate gyro can only provide partial yaw stabilization thrust. Usually the amount
of yaw stabilization thrust is controlled by the gyro gain. Increasing the gain will make the helicopter
more resistant to random turning, but it also decreases the pirouette rate because the
gyro will fight against both random and intentional yawing movement.
A yaw rate gyro cannot provide "heading hold" capability because it only pushes against the
turning movement but will slip somewhat, and once it's been turned it cannot return the helicopter
to the original orientation.
A yaw rate gyro "slips" when trying to countering tail movement, so it cannot effectively counter
main rotor torque. Therefore, the main rotor counter thrust is provided by the revo mixing function
on the transmitter.
The revo mixing allows you to set the tail rotor thrust for each throttle position so the tail rotor
thrust exactly counters the main rotor torque. There is no formula for setting these values; they
must be empirically set by trial and error.
How Helicopters Work
137
The turning thrust is governed by the rudder stick on the transmitter, the same as in a heading
hold gyro.
23.6.3. Heading hold gyros and how they work
For a Heading-hold gyro, the functions are controlled by the following devices:
• Counter main rotor torque - heading hold gyro
• Turn (yaw) the helicopter - rudder stick via heading hold gyro
• Stabilize yaw - heading hold gyro
A heading hold is more sophisticated than a yaw rate gyro and functions completely differently.
The first big difference between a heading hold gyro and a yaw rate gyro is that the heading
hold gyro has a microprocessor on-board and can remember how much the helicopter has
turned. Therefore if a random wind gust turns the helicopter, it can always return the helicopter
to the original orientation.
Therefore, the heading hold gyro can supply the correct main rotor counter thrust automatically
because it doesn't "slip". When you apply throttle and the tail starts to move because there's
more main rotor torque, the heading hold gyro can increase the tail rotor thrust to turn the tail
back to its original position.
Also, the heading hold gyro can provide the correct yaw stabilization thrust because it doesn't
"slip", and therefore it can retain the correct orientation at all times.
The second big difference is the rudder signal from the transmitter no longer directly controls
the tail thrust. The rudder signal tells the heading hold gyro how many degrees per second to
turn, and the HH gyro will do whatever is necessary to move the tail to this position.
Note that the revo mixing MUST be disabled for the heading hold gyro to work properly. If the
revo mixing is enabled, then the heading hold gyro will interpret it as a signal to turn the helicopter.
23.6.4. The difference between yaw rate and heading hold gyros
Imagine we have a helicopter with a properly configured yaw rate gyro and the motor is disconnected
and it is on the ground where it cannot turn. If we hold left rudder on the transmitter for
one second and then center the stick, the servo will move to one extreme servo position for
one second and then center.
Now, imagine we have the same helicopter with a properly configured heading hold gyro, and
the motor is disconnected and it is on the ground where it cannot turn. Imagine that the setting
for this heading hold gyro is full left stick is 180 degreees per second.
If we hold left rudder on the transmitter for one second and then center the stick, the heading
hold gyro will know the helicopter should turn counterclockwise 180 degrees.However, since
the helicopter is on the ground and cannot turn, the tail servo will stick at one extreme and stay
there - the heading hold gyro will keep trying to turn the helicopter. If we manually pick up the
helicopter and turn it counterclockwise 180 degrees, the servo will finally center.
Note that both types of gyros only stabilize YAW. Neither type of gyro will stabilize roll or pitch.
Technically speaking, a helicopter gyro contains an angular acceleration sensor for only one
axis.

If you kick a GY series, or telebee etc, pretty much any gyro I know of than yours into rate mode it acts as described above and must have REVO or a pilot capable of manual mixing (diag movement of throttle stick).

Steve

[Fireant]

Steve

I also did some more reading and got a little more educated at the same time http://www.raptortechnique.com/gyroinfo.htm. I understood the basics of gyro functions, but learnt a little more about the differences and hence the reasoning behind revo mixing.

a pilot capable of manual mixing (diag movement of throttle stick).

Because I fly normal mode with my scale models and the control movements are relatively smooth :), coupled to the tendency of the fus to want to weathercock into wind, I will fly the rudder. The same goes for when I setup any HH gyro and check the mechanical trim. I'll fly gentle lazy 8's in normal and then switch over to HH. No sudden control movements (well, not planned ones). Again, because I've been used to flying the rudder as well as maybe misunderstanding the info from CSM's HH setup when I was a novice, I've never implemented revo mixing.

So, I see the need for revo if you only go for non-HH, but at the same time, depending on the pilot's skill and style, a model can be flown without.

[swatson144]

lollol My buddies dad is an EE and genuine Nasa rocket scientist. We often fly around him and I've let him have a few goes at the corona. Usually a conversation gets started because of helis being so economical (well from a rocket scientists view). One such conversation was started by discussing switching a "rate" gyro for HH. After processing the fact that we actually had gyros which apparently cost more than a couple hundred dollars for a rocket or missle, It was pointed out in his experience all gyros are "rate" gyros, which was pretty much inarguable as rate pretty much equals acceleration. He really didn't understand the difference (in heli vernacular) until the lack of feedback was pointed out. As best I recall he mentioned that he couldn't see much use for a gyro that didn't keep track of both where it is and where it was to go. Again pretty much inarguable and I mumbled something about cheaper.

Given that an honest EE knows that all gyros are "rate" gyros we just use the term to describe a non HH as rate, though a HH is a rate gyro with feedback. I suppose if a manufacturer wanted the standard/normal/unenhanced mode of their gyro to be called "rate mode" even with feedback and the enhanced mode with full use of the software etc as HH that wouldn't be incorrect either. I suspect this is what CSM is doing Kinda a HH with decay so persistant forces would have the same effect as "rate mode" Best of both worlds and certainly makes me want to look into CSM gyros again.

I do know that on a typical plane jane "rate gyro" ala PG-03, PG-02, helimax, most all the other HH gyros in normal, etc some form of mixing is required. If one was to be doing it manually he'd have to add 1/4 rudder stick to full throttle stick to compensate. If it was setup perfect without revo the only place the rudder would be centered is at flat smooth hover. Even with revo one must control the tail as it's never perfect.

That's all the mixer boards in the xn1 RTFs do give a %of throttle mix to the rudder chan. and a way to adjust the center so it doesn't want to yaw at hover.

Steve

[estarter]

"HH" / "TL", head holding/tail lock is just a name, it is all in the control feedback system whether it is software or hardware. With the advance of the electronics, things can be done faster, smaller and easier, hopefully cheaper.

With the affordable HH gyro, I haven't touch the REVO mixing in the Tx for most of my CP helis.

[swatson144]

After this conversation I just ran across a CSM ICG400 gyro on feebay and bought it for about the cost of a PG-03 8-)

I'm looking forward to tinkering with it.

On a side note I'm finding some really good gyros that don't end in 201 or 401 going pretty cheap while the aformentioned gyros are getting very close to MSRP.

Steve

[G-MRM]

Hi Steve, I took a chance on someone selling a cheap GY401, says he sold the T Rex 450 and the buyer did not want the gyro... £35 with post with 2-1 $-£ $70 may still sound a lot for you but here is is cheap...... well it is if it works! lol lol

[swatson144]

Congrats 70$ is very cheap. With all the new(by) demand and the solid rep of GY401 I've seen used prices go from ~80$ a couple years ago to at least 100$ now. 80$ I'd buy used but for >100$ I just buy new.

I keep seeing good prices on the JR gyros 500T and 770 are pretty low priced used and I think it's time to broaden my horizons.

Steve

[G-MRM]

Morning Steve, yes new here from Uk sellers, not shops, £70 $140, but most 2nd hand sellers still want £50 or so, I would then pay the extra and buy new!

I still like my cheap TeeBee or what ever it's called that I fly on the Mini Titan, for my flying skills it's all I need but I like 401's on the big 50 size.

The Agusta 109 has the early CSM 400 gyro, it should be Ok as Ant said it was fine for scale work and he flew the heli with it Ok. If I find it a problem this is where the 401 may end up, will fully test on a cheap heli first !!!!

[swatson144]

You are sure lucky if you like the TeleBees and their rebadges. I don't know wether it's me or them but I've never been able to get one right. I seem to be able to get them to act OK for a while and then I'll do something they don't like and end up landing with a whole lot of rudder to keep it from piro'ing. This is the same even if I fly a friends heli that has a "good" setup. I've got probably 8 hrs (and 2 crashes) in trying to setup a Eflite G-90 with some very bad problem manifesting itself. Fix one problem only to discover another. All the while acting right until I discover the combination to make it go Wacko. I decided I'm too stupid for it and and stuck a LogicTech 2100T on X400 #2.

Looks like we'll both be running a CSM 400 then. CSM is a brand that is pretty rare over here. I had a HLG 200 that was fine. I seem to recall the only thing I didn't like about it was there is no rate mode to help get the tail setup for mechanical center in a hover. It'd work OK without mechanical centering but worked very well with it. So I'd just bypass it and hover without. I think the ICG 400 should be a fine gyro.

I found this cheat to setup.

Set the Travel Adjust on both channel 4 & 5 to 100%

Now switch the radio Tx and Rx on and wait for 5 seconds 'til everything is
initialised. Fit the servo arm onto the tail rotor servo so that it's at 90
degree to the case.

Now connect the pushrod to the servo arm and to the tail rotor bellcrank and
adjust so that there's roughly 8 degrees of pitch on the TAIL blades.

Ok.. Now switch the Rx off and then switch it back on and QUICKLY toggle the channel 5 switch two or three times. It needs to be done during the
intialising time, so it HAS to be toggled quickly.

You're now in set up mode, so when you next move the tail rotor stick, it'll
switch an LED on the gyro on or off (depending on the direction you move the tail rotor stick). This dictates the gyro sense (reverse or normal).
Decide which way you need it to go and then flick the channel 5 switch "on and off" again ONCE. The tail rotor will "zip" to each end and then stop.
Now's the time to set the travel limits for thr servo, so move the tail
rotor stick until the servo reaches it's mechanical limit and then come back a TINY amount. This only works to limit the servo throw in one direction only, so set that direction and then flick the channel 5 switch again. The tail will "zip" again and then travel to the "other" side so you can use the Tx stick to set the travel limit on the "new" side, so once again, use the Tx stick to move the tail rotor to it's mechanical limit and come back a TINY amount. Done? Ok, now flick the channel 5 switch again and the tail will once again "zip" forst to one side and then the other, then it'll cometo rest back in the centre.

Now switch the receiver OFF and then switch it back on. Job's done and it's set up.

I was very pleased to see independent limits for each side. I'm looking forward to trying it out. It'll be on the Corona first.

Steve

[G-MRM]

CSM being in Uk we see a lot of those here and my first new gyro I ever bought was the micro 420 with the setup as you have posted but one more step the topggle digital servo support on and off.

That gyro has been on my T rex 450xl for 3 years and never been a problem. Sue has my std size (big) 420 on her Sceadu 50 the 400 in the Agusta being same but without dig servo support. I have 2 cased and one un cased HG 200 gyros, as you say good but better to setup in std mode first, I did mine with adding 7deg of tail while servo horns are 90deg etc. Turn the unit upside down to reverse it !! One now is on the Corona, one is on Sues T Rex 450xl and another in on my ECO8. I have seen the cased HG200 on big nitro helis working std servos too.

Martin

[mtpenguin]

Has anyone here upgraded their CX/2 with the e-flight H/H gyro? I'm curious how well that one works every time I see it when I go to the LHS to get more blades.....

[basic]

a HH gyro on a coax would be a bit of a pain, considering the way the 3n1 is setup. I think you would end up running both motors through seperate escs, one for the throttle, one for rudder, with mixing between the 2. you could then use a HH gyro to run the Rudder esc, but you will have issues getting the ESC to initialize, and the gyro may not want to boot up right.
my opinion is that a hh gyro on a coax cx2 is a waste of time and money when the system in place works very well for what it's intended to do.

if you have an extra hh gyro and want something to put it in, get a belt cp or something that has a single main rotor and either a tail motor or belt/torque driven tail.

I've given thought to trying out hh gyros for something other than tail (ie - roll or pitch) but think that the delay that is in the system would make the heli uncontrollable. maybe in a plank....

[mtpenguin]

thanks basic

Good information. I think your right about coax with HH. I just keep seeing it there next to other replacement parts for e-flight.

I saw a product in Model Helicopter Technique magazine that put the mixing on board the heli. This made the mixing immediate and they talked about using that with a 2nd gyro to go flybarless.

Looked interesting.

Never played with a HH gyro. They look complicated, but nothing that can't be de-mistified.


B-)

[swatson144]

What ever you do don't buy that pathetic lump of eflite HH G90 gyro. Worst gyro I have ever tried. the old MS-44 is much better than that festering pile of "works fine as long as you only hover" garbage.

I believe I have the highest opinion possible of that gyro, and those are my kindest words on it.

Steve

[mtpenguin]

Advice taken.

Will stay clear of that one.

Thanks

B-)

[swatson144]

20$ more you can have the way cool logictech 2100t which is about the same size and works very well.

Can't go wrong with a GY401 or up, but you'll pay MSRP because of all the new people wanting them.

I've decided with gyros pony up the money or don't bother. but you can find some good deals on some larger older gyros on ebay for your R50 though. I bought a ICG420 for like 50$ and it works like a champ. Same with the old clunky JR 550T. There are a lot of good gyros from CSM, JR etc and Hitec is rebadging the 2100T those don't see as much pressure from the newbies who only knows "you can't go wrong with a gy401".

Steve

[mtpenguin]

What do you think of the new gyro on the new Blade 400 3D?

For $469 complete with DX6i, bl motor, hh gyro, belt driven tail, this looks like a good way to go. I can re-use that radio for my R50.

But with the G90 being so bad, wondering if you or anyone else has experience with the G110 that comes stock on that new model.


B-)

[swatson144]

IDK about the 110. I do know that I wouldn't ever buy a Eflite product before it had been out in the wild for a while and was either accepted or disparaged. Plus I'd give it plenty of time to be rendered obsolete by another Eflite product. This stance has stood me well.

I didn't buy a DX6 only to need to buy a functionaly adequate DX7 a couple months later.

I didn't listen when Horizon said they weren't going to sell modules for other TXs and then had them on display at SEFF. Came close to buying a DX6 but new it wouldn't cut it!

I didn't buy the G90 (it's my buddy's who won't even let me give it back) Par for the course I suspect the 110 is at least functional.

We won't get into them OEM/rebadging the original Esky CP as the blade CP and then Esky releasing the CP2 with lipo, and Eflite later sneaking in lipo and always charging the money over the horizon cost.

So really I doubt I'll have any opinions on their Blade 400, DX6I, their 2.4G modules or other new products until I hear from an unbiased source I can trust. Well or Ahemm someone puts one in my hands to try.

They have pretty much out Aligned Align.

Steve