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Old Jul 06, 2012, 10:52 PM
Registered User
Joined Jul 2012
5 Posts
@Mdigiovabc the M2x8mm from my media server laptop did the trick. I have a little overhang but as I mentioned it got me at least in flying shape. I haven't had time to fully test everything and re-trim for the center of gravity yet but I do notice I have significant difficulty with forward pitch. Roll and yaw work fine as does pitching backward but I suspect I may be mounted too far back for forward pitch to overcome the new COG. Since its all velcro I'll reposition the battery and see how I do. Thanks for the tip with the laptop. I was tearing through boxes of old equipment when I thought , hmmm looks like a small laptop screw might work.
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Old Jul 06, 2012, 11:36 PM
Eugene
Whizgig's Avatar
Australia, VIC, Delacombe
Joined Oct 2006
918 Posts
Quote:
Originally Posted by mdweaver7485 View Post
Can anyone else provide any more information on this screw?
Hi Mate this is what you want just contact the seller and ask him if the screw pictured in the page dose come with it.

http://www.aliexpress.com/wholesale/...low-pipe-.html

And If anyone wants a complete screw set then goto Google and type in DH 9116 screw and you will find heaps of supliers to get them from
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Last edited by Whizgig; Jul 06, 2012 at 11:53 PM.
Old Jul 07, 2012, 06:02 PM
Steve
sllee51's Avatar
United States, FL, Miami
Joined Feb 2012
27 Posts
Quote:
Originally Posted by Balr14 View Post
I have a DX6i and older model Futaba 6EX. They are comparable in almost all respects as far as programming and ease of use are concerned. Removing old models from the DX6i is a pain in the ass, otherwise the are no major issues. Futaba FASST is the best and most reliable 2.4 ghz protocol. Receivers for either aren't cheap, but you can find orange clone DSM2 receivers for the DX6i for under $20. I'm using two with no complaints. There are no helis that come with Futaba receivers. All Blade helis will work with a DX6i.

If I could pick a radio system based entirely on quality and reliability, without regard to cost, it would be Futaba, Airtronics, JR and Spectrum (in that order).
do you think the dh 9116 would bind with the 6ex ?
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Old Jul 07, 2012, 07:38 PM
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Originally Posted by sllee51 View Post
do you think the dh 9116 would bind with the 6ex ?
No...

The only chance you have with it binding with a better tx is the turnigy 9x or flysky FS-TH9x transmitter, but there is an issue controlling the tail rudder.
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Old Jul 10, 2012, 05:23 AM
motivated flyer
ruszomir's Avatar
Poland, Kujawsko-Pomorskie, Torun
Joined May 2012
22 Posts
Does anybody know if the electronic gyro on 9116 is controlling other movement axis than tail rudder?

I was successfully able to hover, fly in circles etc.

Now, I can't get back to hover on my 9116 and I'm wondering what parts to change.

In seconds after airborne heli flies backward, which I compensate with aileron stick forward and more throttle. Nothing happens in 1 or 2 seconds, then heli moves forwards and left and flies upwards.
It is very difficult to fly forward, even with full throttle it dives into ground, then without changing stick's positions, climbs up.

It's like flying in large (5+ meters diameter) circle, like pendulum with string attached to main shaft and hung about 10 meters above ground.

Swashplate is level, servos working fine, only thing comes to my mind is some play at buckles between swashplate and blade grip.

I also replaced gyro module from 9100 PCB board, but heli flied ok after that swap.

Any help would be appreciated.

Slawek
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Old Jul 10, 2012, 05:45 AM
Eugene
Whizgig's Avatar
Australia, VIC, Delacombe
Joined Oct 2006
918 Posts
Quote:
Originally Posted by ruszomir View Post
Does anybody know if the electronic gyro on 9116 is controlling other movement axis than tail rudder?

I was successfully able to hover, fly in circles etc.

Now, I can't get back to hover on my 9116 and I'm wondering what parts to change.

In seconds after airborne heli flies backward, which I compensate with aileron stick forward and more throttle. Nothing happens in 1 or 2 seconds, then heli moves forwards and left and flies upwards.
It is very difficult to fly forward, even with full throttle it dives into ground, then without changing stick's positions, climbs up.

It's like flying in large (5+ meters diameter) circle, like pendulum with string attached to main shaft and hung about 10 meters above ground.

Swashplate is level, servos working fine, only thing comes to my mind is some play at buckles between swashplate and blade grip.

I also replaced gyro module from 9100 PCB board, but heli flied ok after that swap.

Any help would be appreciated.

Slawek
Have you checked the pins on the inner shaft at the top of the shaft which holds the rotor blade holder on its pivot.
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Old Jul 10, 2012, 06:10 AM
motivated flyer
ruszomir's Avatar
Poland, Kujawsko-Pomorskie, Torun
Joined May 2012
22 Posts
Quote:
Originally Posted by Whizgig View Post
Have you checked the pins on the inner shaft at the top of the shaft which holds the rotor blade holder on its pivot.
Well, yes, there is no play.
I've remachined it by replacing broken pins with some custom pins made from nylon on lathe.
AFAIR heli flied OK after repair.

Do you think I should replace inner shaft and blade grip?
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Old Jul 10, 2012, 06:22 AM
Eugene
Whizgig's Avatar
Australia, VIC, Delacombe
Joined Oct 2006
918 Posts
Quote:
Originally Posted by ruszomir View Post
Well, yes, there is no play.
I've remachined it by replacing broken pins with some custom pins made from nylon on lathe.
AFAIR heli flied OK after repair.

Do you think I should replace inner shaft and blade grip?
No they must be fine so what hapend to the heli before you noticed it doing what it it is now, did you have a crash or a hard landing or did it just start doing it?

And yes the gyro dose control more than just the rudder it helps with all controls to help the heli to be stable, also why did you change the gyro in it to one off a 9100 ?
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Old Jul 10, 2012, 06:37 AM
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Joined Nov 2011
1,246 Posts
Quote:
Originally Posted by ruszomir View Post
Does anybody know if the electronic gyro on 9116 is controlling other movement axis than tail rudder?

I was successfully able to hover, fly in circles etc.

Now, I can't get back to hover on my 9116 and I'm wondering what parts to change.

In seconds after airborne heli flies backward, which I compensate with aileron stick forward and more throttle. Nothing happens in 1 or 2 seconds, then heli moves forwards and left and flies upwards.
It is very difficult to fly forward, even with full throttle it dives into ground, then without changing stick's positions, climbs up.

It's like flying in large (5+ meters diameter) circle, like pendulum with string attached to main shaft and hung about 10 meters above ground.

Swashplate is level, servos working fine, only thing comes to my mind is some play at buckles between swashplate and blade grip.

I also replaced gyro module from 9100 PCB board, but heli flied ok after that swap.

Any help would be appreciated.

Slawek
The electronic gyro only controls the tail motor so to keep the tail from unwanted drifting, it could also be called a "head holding" gyro, as it constantly monitors the motor torque and compensates for any excessive sideways movement. To spin the heli, left or right, you override the electronic gyro and apply or decrease power to the tail motor to make it spin faster or slow it down to make the heli spin left or right.

The flybar is also a physical spinning gyro specifically designed to control the angle of the main blades and ensure the thrust is always pointed downwards, this in turn ensures the heli will fly level at all times, thus, it will actively resist any blade movement outside the horizontal plane, so it will constantly make adjustments to keep the heli horizontally level, at all times, that's what makes this heli so stable, easy to fly, and when the swashplate is correctly adjusted, you will be able to achieve a near perfect hover hands free (when there isn't any wind to upset it). When you fly the 9116 or any heli with a 45 offset head or flybar, you will always be fighting the flybar for any movement authority other than a hover, hence, when you fly forwards, it will fly like it's attached to a long string, so it flies in a pendulum type arc. The nose will dip down when made to move forwards, then fly in an arc, at the end of the arc, the flybar will win out and the heli will stall. The best way I've found is to find the sweet spot, between the flybar taking over and bringing any forward momentum to a halt. Unfortunately, this means the lack of any real fast forward speed. Or alternately, fly fast and use the arc to your advantage, by pushing it hard forward, and at the top of the arc, spin the tail around and fly fast forward in the opposite direction. A bit like the skateboarders ride a half pipe. Another way is to fly like you are riding over waves, just before the heli starts to pitch up, pull back on the stick quickly then push forward again and start over, continuing on the same heading.

Ideally, you,as a beginner, must learn how the heli flies and then anticipate what it will do in certain circumstances and fly it around any particular drawbacks, so it's drawbacks don't take over. It's those drawbacks that most beginners (including me when I started) aren't aware of, and that is usually why the heli crashes early in the learning curve, because a beginner is usually either over-confident in their abilities or is too impatient to find out the safe and reliable way to fly it, usually at the expense of replacing many parts, but eventually a beginner will come to the conclusion that they should either slow down and actually learn to fly the heli properly, or they give up in anger and frustration.

Knowing now how my 9116 flies, I can fly it 100m or more in a straight level flight path, without letting it succumb to the pendulum effect, by not pushing it so hard and slowly get the heli to go fast enough by being patient and allowing it to build up speed over a longer distance. if you maintain a steady throttle and apply the elevator and aileron smoothly and with confidence and utmost control, you will crash less and get more enjoyment from it because you are 100% in control, and knowing how the heli will react in certain circumstances means, if you get into a unfavorable situation, you can use the pendulum effect to get you out of a bad situation, like if you are heading towards an obstacle.
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Last edited by stormforce; Jul 10, 2012 at 06:53 AM.
Old Jul 10, 2012, 06:38 AM
motivated flyer
ruszomir's Avatar
Poland, Kujawsko-Pomorskie, Torun
Joined May 2012
22 Posts
Quote:
Originally Posted by Whizgig View Post
No they must be fine so what hapend to the heli before you noticed it doing what it it is now, did you have a crash or a hard landing or did it just start doing it?

And yes the gyro dose control more than just the rudder it helps with all controls to help the heli to be stable, also why did you change the gyro in it to one off a 9100 ?
unfortunately I've a lot of hard landings, due to wind gusts at my location. (kehm, as well as low skills

I've changed the gyro, because one on my 9116 PCB board was broken due to hard crash. The failure occurred as not holding the tail.
As I had fried PCB of 9100 laying around, I changed only gyro element, and It worked like a charm.

As you Whizgig said, if the other controls ARE controlled by gyro, I think that I have to replace PCB board (gyro).
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Old Jul 10, 2012, 07:11 AM
Eugene
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Australia, VIC, Delacombe
Joined Oct 2006
918 Posts
Quote:
Originally Posted by ruszomir View Post
unfortunately I've a lot of hard landings, due to wind gusts at my location. (kehm, as well as low skills

I've changed the gyro, because one on my 9116 PCB board was broken due to hard crash. The failure occurred as not holding the tail.
As I had fried PCB of 9100 laying around, I changed only gyro element, and It worked like a charm.

As you Whizgig said, if the other controls ARE controlled by gyro, I think that I have to replace PCB board (gyro).
Well considering the gyro was from a fried PCB then I would say that the gyro has gone so you would have to replace the PCB.

Yes Mick I thought it didnt control anything but the tail as in heading hold but if you rotate the heli side to side on a fixed pivot the gyro will react to throttle aileron and rudder to keep the heli stable as well as the fly bar as well this allows you to be helped in flight and in auto recovery as well
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Old Jul 10, 2012, 07:27 AM
motivated flyer
ruszomir's Avatar
Poland, Kujawsko-Pomorskie, Torun
Joined May 2012
22 Posts
Quote:
Originally Posted by stormforce View Post
The electronic gyro only controls the tail motor so to keep the tail from unwanted drifting, it could also be called a "head holding" gyro, as it constantly monitors the motor torque and compensates for any excessive sideways movement. To spin the heli, left or right, you override the electronic gyro and apply or decrease power to the tail motor to make it spin faster or slow it down to make the heli spin left or right.

The flybar is also a physical spinning gyro specifically designed to control the angle of the main blades and ensure the thrust is always pointed downwards, this in turn ensures the heli will fly level at all times, thus, it will actively resist any blade movement outside the horizontal plane, so it will constantly make adjustments to keep the heli horizontally level, at all times, that's what makes this heli so stable, easy to fly, and when the swashplate is correctly adjusted, you will be able to achieve a near perfect hover hands free (when there isn't any wind to upset it). When you fly the 9116 or any heli with a 45 offset head or flybar, you will always be fighting the flybar for any movement authority other than a hover, hence, when you fly forwards, it will fly like it's attached to a long string, so it flies in a pendulum type arc. The nose will dip down when made to move forwards, then fly in an arc, at the end of the arc, the flybar will win out and the heli will stall. The best way I've found is to find the sweet spot, between the flybar taking over and bringing any forward momentum to a halt. Unfortunately, this means the lack of any real fast forward speed. Or alternately, fly fast and use the arc to your advantage, by pushing it hard forward, and at the top of the arc, spin the tail around and fly fast forward in the opposite direction. A bit like the skateboarders ride a half pipe. Another way is to fly like you are riding over waves, just before the heli starts to pitch up, pull back on the stick quickly then push forward again and start over, continuing on the same heading.

Ideally, you,as a beginner, must learn how the heli flies and then anticipate what it will do in certain circumstances and fly it around any particular drawbacks, so it's drawbacks don't take over. It's those drawbacks that most beginners (including me when I started) aren't aware of, and that is usually why the heli crashes early in the learning curve, because a beginner is usually either over-confident in their abilities or is too impatient to find out the safe and reliable way to fly it, usually at the expense of replacing many parts, but eventually a beginner will come to the conclusion that they should either slow down and actually learn to fly the heli properly, or they give up in anger and frustration.

Knowing now how my 9116 flies, I can fly it 100m or more in a straight level flight path, without letting it succumb to the pendulum effect, by not pushing it so hard and slowly get the heli to go fast enough by being patient and allowing it to build up speed over a longer distance. if you maintain a steady throttle and apply the elevator and aileron smoothly and with confidence and utmost control, you will crash less and get more enjoyment from it because you are 100% in control, and knowing how the heli will react in certain circumstances means, if you get into a unfavorable situation, you can use the pendulum effect to get you out of a bad situation, like if you are heading towards an obstacle.
Well, I'm confused Stormforce. You said that gyro controls only the tail, while Whizgig said that other axis too.

Thanks Stormforce for explaining pendulum effect in simple words. Unill now I thought of smaller pendulum, like couple of centimeters.

Although I'm beginner, the things were OK, hover, small circles etc. But something went wrong and now the pendulum effect is so strong, that It's impossible to hover at all, not mentioning hands-free hover.

I'm just seeking solution.
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Old Jul 10, 2012, 07:41 AM
motivated flyer
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Poland, Kujawsko-Pomorskie, Torun
Joined May 2012
22 Posts
Quote:
Originally Posted by Whizgig View Post
Well considering the gyro was from a fried PCB then I would say that the gyro has gone so you would have to replace the PCB.

Yes Mick I thought it didnt control anything but the tail as in heading hold but if you rotate the heli side to side on a fixed pivot the gyro will react to throttle aileron and rudder to keep the heli stable as well as the fly bar as well this allows you to be helped in flight and in auto recovery as well
@Whizgig: the gyro was OK after replacing, heli handled well.

I have a theory that crash or hard landing causes electronic gyro to operate improperly thus causing some strange behavior to heli.
Electronic gyro contains some very small moving element thus making it vulnerable to impact. Maybe it will not fail at first time, maybe the failing curve and it's effect is similar to these one described on this forum.

OK, I'll order PCB and head elements as most probable points of failure.

Thanks for your comments Whizgig and Stormforce.
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Old Jul 10, 2012, 09:02 AM
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Joined Nov 2011
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Quote:
Originally Posted by Whizgig View Post
Well considering the gyro was from a fried PCB then I would say that the gyro has gone so you would have to replace the PCB.

Yes Mick I thought it didnt control anything but the tail as in heading hold but if you rotate the heli side to side on a fixed pivot the gyro will react to throttle aileron and rudder to keep the heli stable as well as the fly bar as well this allows you to be helped in flight and in auto recovery as well
I thought that was just the programmed mix, not the pcb gyro. Normally the mix is programmed to act with throttle, elevator or aileron input, like for take off etc. which is pretty easy to incorporate into the programming.

The pendulum effect is also exaggerated by how far away the center of gravity it is, the closer the CoG is to the rotor head, the less the pendulum effect you will get. The CoG is derived by finding the balance point between the top of the rotor head and the weight of the mass and it's position on the heli, like a fulcrum point. If the heli has a metal frame and a large heavy battery, the CoG will be lower, so in effect, the "string" that decides the length of the arc is determined by the weight of the mass, hence, the heavier the weight / mass, the lower the CoG. Then to make matters worse, the length of the main shaft compounds the issue by adding further length to the pendulum arc. It's a compromise between mass, weight, main shaft length, length and position of the flybar and the gyroscopic progression and the speed of the translating tendency to communicate input from the servos into the rotor head to allocate movement in a particular direction. The longer and heavier the flybar is, will dampen the response of the rotor head from translating the servo's / swashplate input into blade / rotor head movement.

It's all very complicated and difficult to understand at the beginning, but once you understand the fundamental basics of what it does and why, it's easy to look at a heli and know what it will or won't do, by the design that's used.
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Last edited by stormforce; Jul 10, 2012 at 09:22 AM.
Old Jul 10, 2012, 10:55 AM
Registered User
dragnse7en's Avatar
United States, MA, Northampton
Joined Jan 2009
131 Posts
Hello everyone

I picked up my DH9116 in the beginning of this month, and it's wicked fun and easy to fly. I started a thread in the wrong sub-forum, and didn't know that this thread existed. If you care to read my thread, click here

I modded mine a small bit, and have been thinking about the main motor a lot. I would like to find out what size motor it is, and try and match up a more powerful one to drop into the airframe.

I have a Litehawk Aero, and I use the three 800mAh lipos from it to fly the 9116, and I'm getting well over ten minutes of flight time on each pack.

Going back to the motor, running those three packs in one session heats that main motor up and I need to have a cigarette break and let it cool down.

Does anyone know of a heatsink that I can get for it?

If any of my questions have already been answered, I apologize. I'll read this entire thread later on though!
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