geebeer

Hello,

What are the differences between a heading hold gryo and a piezo gyro? Are
there more kinds than that? As a first timer... what type of gyro would be a
good preferable? If, for instance, I were go get a heading hold gryo...
would that hinder me later on after I am doing more than just hovering?

I appreciate your comments!

chris ramakers

A Heading Hold gyro is a big help for learning to hoover.
For flying I set the gyro on normal.

Doubleheli

"GeeBeer" <NotARealOne@ev1.net> schreef in bericht
news:10g3odid0ked51a@corp.supernews.com...


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david

You are confusing the ideas. Gyros are of two construction types - piezo
and mechanical. All modern gyros are piezo.

Within the construction types there are two performance types, HH and Rate

HH gyros lock the tail (hence the head as well) and make it possible to,
say, fly fst sideways with little trouble.

Rate gyros "simply" hold the tail from spinning under torque and so make
flying a model chopper much, much easier.

Buy a piezo gyro (I doubt you could buy anything other) and buy a gyro that
has two settings - rate AND HH.

Good luck

David Are

olaf greck

http://runryder.com/helicopter/f44p1/ " Beginners Corner and Links"

they explain better than me,

best regards

Olaf

steve r.

Can you still get a piezo gyro that's "not" HH (heading hold)? I haven't
seen one in a "long" time. Fortunatly, mechanical gyros have gone the way
of the dinosaur. May they rest in peace! ;-)

GeeBeer, definitely get a heading hold gyro from any of the major brands.
That's Futaba, JR, CSM. There may be others but these are the one's I hear
the most about. Personally, I like Futaba but see what the locals are
flying. All of them will do the job.

Good luck & Fly Safe,
Steve R.

tippy

I'd like to gain a little more knowledge while the thread is going.

I agree with the description of HH hold but only partially with
the Rate description. I was under the impression that the Rate
mode only limited the Rate ( I wondered why they called it that)
the heli will yaw. That's why I agree with the description partially.

Under heavy torque, the yaw will be great but as the gyro senses
yaw, it will simply dampen the rate at which the heli yaws . This limit
is usually adustable.

My gyro does not "keep the heli from spinning" (in rate mode). It keeps the
heli from spinning faster than my eye/hand can stay with it but
it still spins.

As far as learning to hover, HH makes the process easier but you gotta
learn how to control the heli at some point so be prepared to use a little
Rate mode on occasion. It gives your left hand something to do besides
move fore and aft

tippy

steve r.

Hi Tippy,

You're right in one thing, HH gyro or not, you still have to learn to "fly"
the helicopter. Compared to the old mechanicals that a lot of us learned
on, HH gyros are a God send but you still have to fly the machine. Hovering
was not a problem but, in fact, it took me a while to get used to flying
around with a HH gyro. The tail commands are different and it took a little
getting used to. It wasn't a big deal, just different.

As for the "rate" part, I usually use the term "rate, command," this is how
I generally describe it to people who ask.

When flying the gyro in HH mode, it's trying to do just that, hold heading.
The gyro doesn't really "know" which way it's pointed. What it can do,
however, is measure how much the model has turned and how fast. It can then
apply a tail command to counter that movement and bring the machine back to
where it was. All of this is predicated on the tail rotor having enough
authority to do what is needed.

Back when we used mechanical gyros, we had to set the ATV's or travel
adjustments in the transmitter so the tail rotor servo linkages didn't bind
at the extremes. Actually, we'd deliberately set the system up to bind a
"little" at the extremes on the bench. Once the helicopter was in flight,
the gyro would naturally take a little bit of that back, because it couldn't
tell if the turn was commanded by the pilot or not.

With HH gyros, the "gyro" controls the tail rotor servo, "not" the pilot.
That's why you have to do a setup procedure with the gyro itself to set the
servo ATV's or travel adjustments so that the tail rotor pitch controls
don't bind at the extremes. This is "very" important especially with the
new digital servos. If the servo binds at the extremes, it would draw a LOT
of current off the battery, trying to force the linkage to a point that it's
not capable of reaching. That's bad for the battery "and" the servo.

What about the "rate, command" part I mentioned above? The HH gyro will try
to rotate the helicopter at a given rate in degrees/second based on how much
tail command the pilot is giving from the transmitter. How fast the
helicopter will rotate is dependant on how much tail rotor authority the
model has, what the ATV's or travel adjustment settings are in the
transmitter, and how far the pilot is holding the stick over. Assuming that
tail rotor authority is a non issue, and it usually is in most of the models
available these days, the higher the ATV's or travel adjustment settings
are, the faster the model will spin for a given stick position being held by
the pilot. If the tail control is too fast for the pilot, all he/she has to
do is turn the ATV's or travel adjustments down on the tail rotor (rudder)
channel in the transmitter. The gyro doesn't care if the ATV's or travel
adjustments are set to 100% and the pilot is holding the stick 50% over, or
the ATV's or travel adjustments are set at 50% and the pilot is holding
stick "all" the way over. It's all the same to the gyro. The nice part of
all of this is that the pilot can hold the stick at a certain point and the
gyro will try to provide a given yaw rate regardless of what the wind is
doing. With the old mechanical gyros, the pilot had to gradually (sometimes
not so gradually) increase the tail command as the tail rotor pushes into
the wind. Then, when the tail is pointing straight to the wind and crosses
over to the "downwind" side, the pilot has to immediately reduce and
sometimes reverse the tail rotor command to maintain the same yaw rate. It
was difficult to perform a constant rotation rate pirouette in the wind.
Now, with HH gyros, the gyro does all the work. It will apply whatever tail
command is needed to maintain the "commanded" yaw rate regardless of whether
or not the tail is pushing into the wind or being pushed by the wind. If
that means taking the tail rotor to full control right, then full left,
it'll do it, even though the pilot is only holding 1/4 stick over. That's
what I meant when I said that the gyro controls the tail rotor servo and not
the pilot.

One way to see this rate command phenomenon is to set the tail rotor ATV's
or travel adjustments to a certain level, say 80%. Take the helicopter up
(I'm assuming you're capable of doing this safely, or letting someone who is
try this!) and give a full tail rotor command from the transmitter and note
how fast it spins. Next, land and reset the tail rotor ATV's or travel
adjustments to 40% and perform the same test. You'll see that it spins
significantly slower than at the 80% level. That's what they mean by a
"rate," or as I like to say, "rate, command" gyro. It's really cool as far
as I'm concerned.

Hope this makes sense.
Fly Safe,
Steve R.

david

the


Then surely it's incorrectly set up? A standard rate gyro should enable you
to hover the machine hands off, no tail yaw and certainly no spinning,
shouldn't it?

I accept that if you fly the machine sideways etc it WILL then yaw, and it
might even weather ****, but hovering into wind it should exhibit no motion
at the tail that requires permanent rudder stick to be applied.

It should pirrouette well of course when you end-stop the stick!


Thats my understanding anyway. Its how mine work for me.

D

geebeer

Hello,

What are the differences between a heading hold gryo and a piezo gyro? Are
there more kinds than that? As a first timer... what type of gyro would be a
good preferable? If, for instance, I were go get a heading hold gryo...
would that hinder me later on after I am doing more than just hovering?

I appreciate your comments!

chris ramakers

A Heading Hold gyro is a big help for learning to hoover.
For flying I set the gyro on normal.

Doubleheli

"GeeBeer" <NotARealOne@ev1.net> schreef in bericht
news:10g3odid0ked51a@corp.supernews.com...


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