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Old Jan 21, 2012, 03:06 PM
LearningFast
United States, LA, Denham Springs
Joined Jan 2012
410 Posts
Hey Everyone, my tx on light is blinking. I know the batteries are good as I checked the voltage at 8.53 V. Any ideas? On, as stated earlier, my tail rotor motor is acting up. It won't turn unless I move it. It seems to have a bind. I am going to try to clean it. I checked the voltage at the ecs, and it is good and variable as it should be.
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Old Jan 21, 2012, 04:12 PM
Crash and learn
United States, PA
Joined Dec 2011
1,605 Posts
Quote:
Originally Posted by Ken59 View Post
weak rear motor
Low battery voltage under load could cause the tail motor to not reach maximum speed and the main motor is by far the heaviest load. But then the main motor is the first to slow when battery voltage drops.

My DH9104 rotates quite well in either direction at full throttle. Will have to take note if there is a change when the battery runs low. I don't remember any tail problems with a low battery.

If the tail gears don't have a lot of slop (watch the internal coils from the rear while turning the blades), then it likely is the tail motor, specifically the brushes. Take the tail motor apart after you replace it and see what is in there. A good cleaning around the commutator may fix it. I'd like to know how dirty the motors get.

Stormforce took apart a main motor and found carbon brushes. He was expecting simple metal spring contacts.

Try a drop of oil on the bushings when you can get at them.
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Last edited by Ribble; Jan 21, 2012 at 04:20 PM.
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Old Jan 21, 2012, 04:15 PM
Steve
Chester1's Avatar
United Kingdom, Staffordshire
Joined Jan 2012
156 Posts
DH 9116 ordered

Well, I decided to just go for it and have ordered a DH 9116 . It won't be dispatched from HK until after Jan 31 due to the Chinese holiday so probably mid Feb before it gets here - cost me $125 inc. shipping. It will be joining my fleet of 18 other helis. Being the middle of winter not much flying being done - high winds and rain with 5 degC temps - not good
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Old Jan 21, 2012, 04:59 PM
LearningFast
United States, LA, Denham Springs
Joined Jan 2012
410 Posts
ok, what is happening, still after a cleaning, is the motor won't start on throttle until I turn it. I pulled it out and found the positive was not soldered that well and did it again. When I throttle up and it is running, I can go up and down and then it stops. The shafts seems rather "notchy" when turned by had. I believe it is bad. I have another on order, so must wait again. I was flying a little today and got it to hover quite well until the trouble began. Oh, well. Time to walk away for a bit. I will check the batteries on the tx again and see what is up. It is probably just weak batteries.
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Old Jan 21, 2012, 05:08 PM
Crash and learn
United States, PA
Joined Dec 2011
1,605 Posts
I like the DH9116, except for me it is smaller than the DH9104 for outside winds and too big to fly in the house. The 4th channel (ailerons) makes it desirable as in most cases it is a better flying machine and higher on the learning curve than the DH9104.

Goodbye rudder, hello aileron. Enjoy the new found freedom Chester.
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Old Jan 21, 2012, 05:15 PM
Crash and learn
United States, PA
Joined Dec 2011
1,605 Posts
Ken - my tail motor feels very "notchy" when turning by hand, as does the main motor. Magnetics I guess.

I've seen commutators get eaten away from arcing, causing dead spots.
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Old Jan 21, 2012, 05:56 PM
LearningFast
United States, LA, Denham Springs
Joined Jan 2012
410 Posts
Thanks! That sounds as if it may be the problem.
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Old Jan 21, 2012, 06:10 PM
Steve
Chester1's Avatar
United Kingdom, Staffordshire
Joined Jan 2012
156 Posts
Quote:
Originally Posted by Ribble View Post
I like the DH9116, except for me it is smaller than the DH9104 for outside winds and too big to fly in the house. The 4th channel (ailerons) makes it desirable as in most cases it is a better flying machine and higher on the learning curve than the DH9104.

Goodbye rudder, hello aileron. Enjoy the new found freedom Chester.

Yes, I am looking forward to getting it, it should be interesting to say the least. I have flown many 4 channel heli's but most of them are co-axials except my Blade 120SR which is good fun but very 'twitchy' - hoping the bigger airframe of the 9116 will make for a calmer flight. I did have a Blade SR full CP and flew it for about 5 seconds - spent the next 2 hours picking up the pieces
Thats why I'm back into easier fun heli's
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Old Jan 21, 2012, 07:01 PM
Always, against the wind
Thetis's Avatar
United States, IL
Joined Oct 2011
1,074 Posts
Quote:
Originally Posted by Chester1 View Post
Yes, I am looking forward to getting it, it should be interesting to say the least. I have flown many 4 channel heli's but most of them are co-axials except my Blade 120SR which is good fun but very 'twitchy' - hoping the bigger airframe of the 9116 will make for a calmer flight. I did have a Blade SR full CP and flew it for about 5 seconds - spent the next 2 hours picking up the pieces
Thats why I'm back into easier fun heli's
The 9116 has its own learning curve and is not as easy as you think. You need to spend time to master the Tx along with manual trimming. I am sure you have seen the posts for the 9116 in the beginner forum. One more thing that happened to me. I received a Mode 1, and I am used to Mode 2. I was lucky, I have ordered it from Amazon (free shipping in four days) and when I returned it I got a full refund. I don't know what mode you fly but when you receive it check what it is ticked on the back of the box. Opening the Tx and try to convert to mode 2 was a nightmare and never worked properly for me. In addition, the 9116 is more delicate than the 9104 and breaks much easier. My 0.02 cents.
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Old Jan 21, 2012, 07:12 PM
Always, against the wind
Thetis's Avatar
United States, IL
Joined Oct 2011
1,074 Posts
Quote:
Originally Posted by Ribble View Post
Thetis - Stormforce has a test for the gyro. Hold the helicopter and increase throttle then rotate the helicopter by hand - the tail rotor will try to hold heading (correct the yaw).

OK, for the purists, the DH9104 gyro doesn't actually hold heading as it doesn't continue to correct yaw if the yaw isn't corrected.
---

After the crash, the DH9104 now rotates Clockwise (CW) or Counter Clockwise (CCW), looking from above? CCW means a weak tail rotor, while CW means too much tail rotor.
---

Inspect that the flybar does indeed change the blade pitch, no links off the balls, no bent flybar.
---

Another, test that the tail rotor is mixed with the throttle. Remove the main rotor plug from the Electronic Speed Control board. Increase throttle. The tail rotor speed will track the increasing throttle. Also check the gyro again and note that the tail rotor will indeed slow as the helicopter is rotated clockwise.

With the main rotor connector removed, increase thottle. Then test right stick, left and right, and note change in tail rotor speed. Now turn the TX upper right "left/right turn" potentiometer full CCW and test right stick rudder again. Turn pot full CW and test again. Note CCW kills any right stick, left rudder. Do same test with "backward/forward" potentiometer and note no effect on tail rotor, but servo does indeed tilt swashplate forward and backward, as does the right stick elevator control.
Riddle, thanks for your suggestions. I have found out that I have too much right rotor speed and no left at all. I did what you have suggested and these are my findings by mounting the heli on the lazy susan. Now shall I forget her? I have other outdoor helis to have fun, but somehow I like the 9104. No breakage at all after so many crashes.
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Old Jan 21, 2012, 11:59 PM
Crash and learn
United States, PA
Joined Dec 2011
1,605 Posts
Just remembered. One time after putting my transmitter back together again, I had no rudder control. Took the transmitter apart, connector looked OK and potentiometer wiring looked OK. Pulled connector out and put back in and it worked again.

DH9104 49MHz transmitter connectors:
1 - Throttle
2 - Backward/Forward Elevator
3 - Left/Right Rudder
4 - Backward/Forward Trim Knob
7 - Left/Right Trim Knob

Never did figure out why there are 5 distinct proportional inputs to the controller integrated circuit. Maybe it is a 5 channel transmitter - someday I will drag my oscilloscope out and watch the waveform to see exactly what is being transmitted.
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Old Jan 22, 2012, 12:09 AM
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michaeldepeza's Avatar
Trinidad & Tobago, St Andrew, Valencia
Joined Jan 2012
171 Posts
Please post pics of this soldering mod/adjustment of transmitter

Quote:
Originally Posted by Ribble View Post
I just took my 49MHz DH9104 outside (in the dark).

With helicopter sideways (on the ground) I get roughly 10 meters (30 feet) with the transmitter antenna removed before the helicopter red LED goes out. A foot closer LED comes back on. Solid with antenna back on the transmitter and collapsed. That is as far as I can go in my back yard.

Transmitter antenna removed:
Originally, with helicopter antenna tied to tail, I got 2 meters.
After refolding antenna on skid (as out of box), I got 3 meters.
After tied to tail again and tuning receiver, I got at least 5 meters, but was behind an inside wall and ran out of room.

Then I soldered the bad connection in the transmitter at the antenna connection. Now (outside) I get 10 meters line of sight, no transmitter antenna.

When tuning the receiver, I let the helicopter battery hang down and used a small jewelers flathead screwdriver to turn the slug inside the antenna coil (up through battery holder). But I used too much force and the slug and top wax popped out the top and fell in the receiver board - the slug is so small that it would have been hard to find otherwise. Slug back in and kept walking away from antennaless transmitter and tuning for best distance, watching helicopter red LED.

So, tuning the receiver worked, but it is very easy to lose the tuning slug or do other damage, and I don't recomment it.

hey bro please post or send me pics of this antenna mod/soldering adjustment...i really need more range out of mine......also
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Old Jan 22, 2012, 12:11 AM
Always, against the wind
Thetis's Avatar
United States, IL
Joined Oct 2011
1,074 Posts
My Tx is 27.145Mhz. I will open and check it out, but the heli was crashed not the Tx.
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Old Jan 22, 2012, 12:44 AM
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michaeldepeza's Avatar
Trinidad & Tobago, St Andrew, Valencia
Joined Jan 2012
171 Posts
link on amazon for 9116 swashplate

http://www.amazon.com/Double-Horse-H...sim_01_04_t_lh

link for 9116 swashplate buckles and blades(most likely too small to power 9104)

http://www.amazon.com/Double-Horse-H...ref=pd_sim_t_2

link to site selling parts inclusive of PCB for 9116

http://www.feala.com/double-horse-91...-and-parts.htm


Question:wondering if converting 9104 to 9116 4ch is worth it............hmmmmmm
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Old Jan 22, 2012, 12:48 AM
Crash and learn
United States, PA
Joined Dec 2011
1,605 Posts
michaeldepeza - Well there were several. Do a range check first.

First remove the transmitter antenna and walk away from the helicopter until the red LED under the canopy goes out. About 30 feet (I flew my DH9104 for the first two weeks with no transmitting antenna).

Put the transmitting antenna back in and keep on walking. I'm guessing range was about double. If you can't see the helicopter anymore, then your transmitter should be OK. If not I can help.

Next, wrap the helecopter receiving antenna back on the skid as it came out of the box. If you didn't unwrap it, then skip another range check. I found that the receiver was tuned for the antenna on the skid.

OK, now you have to decide if you really want to do this. The DH9104 receiver antenna is soldered to the Electronic Speed Control (ESC) board. Next to that is an upright coil with melted wax filling the hole. Underneath the wax is a movable ferrite slug that is threaded so turning it with a very small screwdriver moves the slug up and down inside the coil. Ideally it should be a non-metallic tuning wand, but I didn't know what was in there, so I put a jewelers screwdriver in from the bottom and pushed and turned.

If you never tuned a coil before, then I advise not doing it because you will likely damage the slug, the coil, or the ESC board itself. And the best way is to do it with the ESC connected to the battery and turned on.

However, since you will nuts it up anyway (I did), best to keep the battery disconnected (the switch only turns ON/OFF the +5 volts and the ESC board itself is hot at battery voltage).

So, you have to get the wax out of the coil somehow and after that you have to be able to adjust the slug. That done, you can tune the receiver.

TUNING THE RECEIVER
Remove the antenna from the transmitter and set it flat. Walk away with the helicopter until the red LED goes out. Adjust the slug until the red LED comes back on. Walk farther and repeat. Etc.

Getting that far, try unwrapping the receiving antenna from the skid and tie it to the tail plastic part. Repeat the walk and adjust.

Again, if all this is Greek to you, then better not done. Good luck.
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