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Old Nov 05, 2009, 07:24 PM
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Livermore, CA
Joined Sep 2004
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Coaxial without gyro??

The coaxial's seem so stable. Is a gyro really nessary??
Anyone fly one without one?? Thanks, Butch
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Old Nov 06, 2009, 12:11 AM
All flight is 3D.
various parts of NY
Joined Jan 2009
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Yeah... it would just be a lot harder to keep it pointed in one direction. But it is possible. In the early days of rc helis there were guys who flew single rotors w/o gyros. Or so I've been told.
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Old Nov 06, 2009, 01:26 AM
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Quote:
Originally Posted by Lamedico View Post
Yeah... it would just be a lot harder to keep it pointed in one direction. But it is possible. In the early days of rc helis there were guys who flew single rotors w/o gyros. Or so I've been told.
Definitely a gyro on a coaxial is a plus plus.

There is a big difference in controllability. I've experimented on such on 3 channel coaxial helis without gyros by default and by adding such;

3 Channel RC Helicopter : Gyro Magic (1 min 6 sec)


Badminton Mania - 1 (0 min 50 sec)



At the workbench: 3CH Tight Flight - 2 (1 min 6 sec)



Maneuverability: Indoor Obstacle Course with a 13 gram coaxial helicopter - Attempt 1 (1 min 2 sec)
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Old Nov 06, 2009, 01:57 AM
OlliW
Joined Sep 2009
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Hey Butch,

I am currently developping my own 3in1 for a lama v4 and in the course of that I flew also without gyro, to test things, to find some settings, and - yes - to just see the difference. Anyhow, I was amazed how well my lama flew without gyro, I would have expected something much much worse (and don't belive that this is because I am such an outstanding experienced pilot... ). So, with the proper settings it is not that bad, but, of course, it's much better with a gyro.

Olli
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Old Nov 06, 2009, 06:34 AM
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Springfield, VA USA
Joined Sep 2008
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Butch,

Having first used 3 co-axial toys that did not have gyros before the CX2 came to market, my conclusion was that gyros made all the difference in control. It was not just a question of experience or skill, it was the simple fact that gyro control of the heading freed you up to actually fly rather than react to what the helicopter was doing in flight.

AH-64 D
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Old Nov 06, 2009, 09:13 AM
Multifaceted Heli Nut
USA, GA, Atlanta
Joined Oct 2004
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I've flown my Sovereign Tech Helibaby coax with the yaw gyro shut off. As long as the differential collective pitch is tuned correctly, there's minimal yawing force generated from the blades but if you input a yaw, the heli can start rotating extremely fast and is 'fun' to arrest. Just give small yaw inputs and try to avoid wind coming from behind the heli. No video available of gyroless flying yet but there will be when I find the time.
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Old Nov 06, 2009, 02:08 PM
Fly Runaway Fans
United States, TX, Fort Worth
Joined Jan 2009
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I've got 3 coaxes. Submicro, no gyro. Micro with rate. Micro with HH.

The sub is a jolly challenge, to have/keep it pointed while engaging ELE. So light, the consequences of failure are negligible. Kinda rewarding when you can tame it. It's a $20 giggle to fly, I got from Walgreens.

The rate drifts with battery state and temperature, but well within range of pilot load. This is a Lama V4, $100. It doesn't need to point where it goes, it has aileron. Gyro snaps from RUD commands to whatever state of drift it has at the time.

The HH is, of all things, another 3ch. $60. The ad blurbs don't claim gyro at all. But the snap is very aggressive when RUD is released, and batt/temp drift just isn't there.

People flew helis for decades before gyros were invented. Seems though, coaxes and gyros were invented about the same time. As most are light, little inertia, zero tail authority, seems they are made for each other. I definitely wouldn't want to fly a 17" coax in a 7-foot space without gyro. But with a good one, even without aileron, it's manageable.
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Old Nov 06, 2009, 07:24 PM
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Livermore, CA
Joined Sep 2004
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Thanks guys.
The reason I asked is I picked a Walkera 400D and it wouldn't spin(yaw). I picked up another Tx and still no luck. If I held the rudder stick all the way to one side for 20-40 seconds, it would finally move in that direction. Then when I realeased the stick, it would stay in the turning mode a couple seconds more and then go back the other direction.
Knowing that I'll some day put brushless motors on it, I changed the rx to a Berg, and installed 2 GWS ESC,s and a GWS tail mixer last night.
I got it working, but the yaw is real sensitive. I don't have any gryos around, but maybe I'll get one later. Butch
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Old Nov 07, 2009, 01:51 AM
OlliW
Joined Sep 2009
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I don't know your mixer, but I guess the "problem" is that your mixing is way to strong, so you could use a "coaxial" mixer, i.e., one which allows you to adjust the mixing ration, or, since you don't have a gyro in you could equivalently do the mixing in the transmitter (if you have a computerized one).

In my case I used a mixing ratio of 12.5%. So, no wonder your yaw is real sensitive... (assuming your mixer does 100%)

As regards your BL plans, although not absolutely nesseccary since the mixing ratio can be adjusted via the gyro gain, a "coaxial" mixer seem to be useful also then - at least I have read reports that the performance is better if the gyro gain is 100% and the mixer ratio at let's say 20% instead of having the gyro gain at 20% and the mixing ratio at 100%.
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Old Nov 09, 2009, 04:24 AM
All flight is 3D.
various parts of NY
Joined Jan 2009
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Quote:
Originally Posted by arbilab View Post
I've got 3 coaxes. Submicro, no gyro. Micro with rate. Micro with HH.

The sub is a jolly challenge, to have/keep it pointed while engaging ELE. So light, the consequences of failure are negligible. Kinda rewarding when you can tame it. It's a $20 giggle to fly, I got from Walgreens.

The rate drifts with battery state and temperature, but well within range of pilot load. This is a Lama V4, $100. It doesn't need to point where it goes, it has aileron. Gyro snaps from RUD commands to whatever state of drift it has at the time.

The HH is, of all things, another 3ch. $60. The ad blurbs don't claim gyro at all. But the snap is very aggressive when RUD is released, and batt/temp drift just isn't there.

People flew helis for decades before gyros were invented. Seems though, coaxes and gyros were invented about the same time. As most are light, little inertia, zero tail authority, seems they are made for each other. I definitely wouldn't want to fly a 17" coax in a 7-foot space without gyro. But with a good one, even without aileron, it's manageable.
Gyro's were around for a long time. I remember hearing about people experimenting with them in the early 70's. Mechanical gyro's too.
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Old Nov 09, 2009, 08:21 PM
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Didn't the first coax fly in the 50's?

As far as things go, I'd say that with a mechanical drive train, collective pitch, and one motor, that a gyro would not be necessary. On the other hand when using two motors that are supposed to perform identical (but usually don't) a gyro becomes almost a necessity.

I'm sure it's possible to fly a coaxial without one, but in a larger rc coaxial, who would really want to?
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Old Nov 11, 2009, 10:45 AM
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Canada, ON, Ottawa
Joined Jun 2009
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I have a palm size 3CH co-axis, 6020, without a gyro. I have to trim it in flight all the time to stop it from spinning. I have to add yaw on back and forth flights to keep it go straight. It is possible to fly but a bit challenging.

I've added another 3CH palm size co-axis, CF-555, with gyro a couple of days ago. This one is so stable that it is almost too dull to fly. It moves up and down, back and forth as if we are driving a car on the ground. It does not feel like we are flying a helicopter.

The difference between with/without gyro is very obvious.
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Old Nov 11, 2009, 01:28 PM
Fly Runaway Fans
United States, TX, Fort Worth
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Gotta wonder how Kamovs manage.
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Old Jun 04, 2010, 08:29 PM
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Hi Butch, re your Gyro comment. I mastered a single rotor Poly toy, upgraded to a S105 without a gyro, fun to fly. Upgraded again to a S107 with Gyro, better stability, less seat of pants. But gyro circuitry failed, copter now oscillates (hunts) forward, reverse, left, right, up and down. Totally suicidal. Even attempts ground loops and rolls. Will eventually replace the PCB, unless I find some component specs, but till then I have dusted off the old 107. Not knocking gyro assisted flight, both are fun.
Cheers
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Old Jun 05, 2010, 11:19 AM
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I'd assume the Kamov has a gyro- military stuff hopefully is at least as advanced as these $30 Poocopters.

My first few 6020's and 8818's were non-gyro, and you really had to be a good rudder man to guide them along in anything resembling forward flight.
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