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Old Oct 24, 2012, 04:37 AM
Ret. CH-46 Pilot USMC
United States, OH, Whitehouse
Joined May 2012
85 Posts
Ray...

just curious... the signal dropout is nerve racking indeed. I would be tempted to get some tent pegs and nail it to the ground. Then walk in ever widening circles with rotors spinning.

How far away did you get?
How long from start time does it usually happen?
Are you in any particular direction away when it happens?
Have you opened x-mitter to check the solder joints and for loose parts?

grasping at straws...lol
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Old Oct 24, 2012, 08:14 PM
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Originally Posted by boulier1 View Post
Ray...

just curious... the signal dropout is nerve racking indeed. I would be tempted to get some tent pegs and nail it to the ground. Then walk in ever widening circles with rotors spinning.

How far away did you get?
How long from start time does it usually happen?
Are you in any particular direction away when it happens?
Have you opened x-mitter to check the solder joints and for loose parts?

grasping at straws...lol
Hi boulier1,
The cutouts are random in everyway including distance except that now on the new board their happening at around the half way point during a flight, were as with the old board it would do it at just about any time during the flight. I did check out the inside of the transmitter a few months back when it was happening with the old board.

I did just finish a 10th flight with the new PCB board on my 8006 and again it cutout, but luckily the helicopter once again recovered just in time. I am baffle by why there was not a hint of a cutout on the first 7 flights, and now since the 8th flight its cutout once on each of the last 3 flights at around the half way point during the flight.


I have been able to rule these things out for causing the power cutouts;

1] The batteries in the transmitter - The batteries have lots of power and work with no problem in my 2.4ghz airplane transmitter and that transmitter flies my airplane over 1000 feet out with no problem.
2] The antenna wire - I double its length and ran it straight back to the lower part of the tail support and still the helicopter cutout.
3] I eliminated the ON / OFF switch - but still the helicopter cutout.
4] Immediately upon landing I used my fingers and touched all the electronic parts on the new PCB board - and everything was very cool to the touch.
5] Since putting the new PCB board on the helicopter its kind of strange that it didn’t cutout not once until the 8th flight - I think that tends to rule out the transmitter itself as being faulty since a faulty transmitter would be causing a problem on every flight.

So basically that really only leaves radio interference as being the problem, but then why didn’t it affect the helicopter on the first 7 flights. But then again if its interference, why isn’t causing other control problems on the helicopter. Since buying the helicopter new I have been noticing that the helicopter does sometimes do a little quick nose twitch to the right, but I wrote that off as probably being a bug in the 8006 radio system since my helicopter always responds exactly to my transmitter controls and never really does anything else strange.

I also figure since there hasn’t been much complaining about this problem on the thread, then the problem has to be due to some sort of random interference that interferes with my 8006’s transmitter in my flying area.

It really looks like to me that a different transmitter / receiver maybe the only way to fix the problem.

Ray
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Old Oct 24, 2012, 10:28 PM
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Hey guys. Here's really good LCD lipo battery Balance charger, that tells you the voltage in each cell, and it don't cost much at all (Free shipping). Plus it's a US order, so no waiting for weeks from china..

Mike...

Oh, as for your cutouts Ray. It must be from interference in your flying area, as I've haven"t had cutouts yet (Touch wood) But I don't let my heli go to far from me. Also, is the 27mHZ version am or fm (That I use)...

http://www.ebay.com/itm/3in1-RC-2s-6...item43afadeb8b
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Last edited by hooleydog; Oct 24, 2012 at 10:39 PM.
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Old Oct 25, 2012, 01:40 AM
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Originally Posted by boulier1 View Post
The motors need 2 things to run.....current and voltage. MOSFETS can be used to control both... see where that is leading my friend... check current under load, the motor, put ammeter and dvm on and watch....
Now....since it has been a while, and I have slept since then is this about adding twin tail rotors? Can we make a set of main rotor blades work on the tail?

Is there another motor with higher rpm?
What is the tail rotor motor?
Do you have it's parameters?
Can the gears be changed?
Can a different prop with a more aggressive angle of attack be used?
In it's basic form the problem is how to generate enough air flow to keep the nose down....


The difference in the second board, did it have the newer transistors? When you remove them, could you test the hfe, just curious.
Do you have a scope? A curve tracer would be real handy...
Hi boulier1,
Both PCBs have the original TO-92 882s and no I don't have a scope.
I was hoping to get this idea tested before posting pics but I’m at the “what the hell do I do now stage” so some pics of what I’m trying to do are uploaded.
Constructive suggestions, ideas or thoughts welcomed.

I see two options: Generate/supply/provide a PWM signal from the tail rotor pin - + voltages to operate the swashplate servo.
Pros: PWM would automatically keep/return the servo to centre position (neutral/hover) when no juice is applied. This set up would retain the original board and could be paralleled with the tail rotor motor provided the 882s could handle both and I don't see why not as I have had two N50s connected in parallel on an 8006 without problems before and servos don't drag that much current.
Cons: Added weight. Zero control volts would automatically return the servo to centre position (neutral/hover). A bit each way with this one as the natural tendency for the heli to return to level flight would come into play as soon as the forward/back control was centred and the servo returned to centre position (level flight).

The other option is using a 12 volt 6RPM reversible motor/gearbox to operate the swashplate with voltage supplied directly from the - + tail rotor pins. Pros: This is probably the simplest option. Once set in forward flight position the lower blades should remain in that attitude until opposite voltage is applied. No need to continuously hold the control on.
Cons: Added weight. Touchy control, hold the forward/back control on too long and the lower blades get turned inside out as would most of the heli as the motor/gearbox is 360 degree rotation type. May have to reduce voltage to around 3 volts to slow the motor/gearbox RPMs even more than the current 6RPM (more weight/electrics). Slow response/recovery from an over control situation. Hover position of lower blades (level) could only be guessed. Tail rotor becomes an ornament.

Either way, lower blade movement up or down has to be limited to a maximum of 20mm at the tips to minimise/avoid blade, canopy strike or the need to extend the centre shaft.... yet.
Main shaft assembly has been moved to new version position and canopy has been lowered 8mm at rear screws and 10mm at front screws. This has angled the canopy down at the front enough to minimise potential for blade strike. Battery located under drive gears as new version.

This is only a rough mod until I can determine whether this will actually work. At the moment I'm only working with longitudinal pitch control of the lower blades. If it works and it's a BIG IF, I may then look at doing a "proper" job. Depends on results but maybe a second servo to change the lower blades angle of attack as well as pitch. In theory, a 5 degree change in pitch angle should provide enough lift for better forward/back lift/flight while also overriding the upper blades tendency to lift the heli back to level flight.

Like Ray I still have the odd cut out to deal with but under test conditions I have been able to reproduce the cut outs with a 90% success rate and I’m leaning heavily towards interference as the cause as I deliberately introduced interference into the tests. How to solve it is another matter added to my “to do” list.
cheers,
Ken
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Old Oct 25, 2012, 11:47 AM
Ret. CH-46 Pilot USMC
United States, OH, Whitehouse
Joined May 2012
85 Posts
On heli's with cutout probs...are any wires to PCB using connectors? Ray's makes me think connectors due to length of time with no prob then it rears it's ugly head. With as much vibration as these go through I'm surprised you don't see more. Besides one little hiccup in the PULSE WIDTH MODULATION stream would also cause it to cut out or reset and that could be an intermittent connection, wonder if all connections being soldered would help? Couldn't hurt. Plus minimize wire movement by using mini tyraps. I would also try adding 1 battery cell at a time to x-mitter to kick signal up a bit
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Old Oct 26, 2012, 11:20 AM
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Joined Feb 2011
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Quote:
Originally Posted by hooleydog View Post
Hey guys. Here's really good LCD lipo battery Balance charger, that tells you the voltage in each cell, and it don't cost much at all (Free shipping). Plus it's a US order, so no waiting for weeks from china..

Mike...

Oh, as for your cutouts Ray. It must be from interference in your flying area, as I've haven"t had cutouts yet (Touch wood) But I don't let my heli go to far from me. Also, is the 27mHZ version am or fm (That I use)...

http://www.ebay.com/itm/3in1-RC-2s-6...item43afadeb8b
Hi Mike,
That looks like a pretty nice battery charger for the Li-Po batteries and the good thing about it is that it can handle all the common size Li-Po batteries plus handle any future bigger helicopter batteries. I wonder if the charging speed is faster than the G.T. Model battery charger.

By the way, the 8005 and 8006 transmitter’s are on AM.

Ray
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Old Oct 26, 2012, 11:25 AM
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Quote:
Originally Posted by boulier1 View Post
On heli's with cutout probs...are any wires to PCB using connectors? Ray's makes me think connectors due to length of time with no prob then it rears it's ugly head. With as much vibration as these go through I'm surprised you don't see more. Besides one little hiccup in the PULSE WIDTH MODULATION stream would also cause it to cut out or reset and that could be an intermittent connection, wonder if all connections being soldered would help? Couldn't hurt. Plus minimize wire movement by using mini tyraps. I would also try adding 1 battery cell at a time to x-mitter to kick signal up a bit
Hi boulier1,
I didn’t think much of it at the time but on the first 7 flights I did land my 8006 once during each flight. On each flight I landed the helicopter about half way thru the flight for only about 30 seconds (and I turned nothing off while landed), and then I finished off the rest of the flight and there was no cutouts. So yesterday when I did the 11th flight, I landed the helicopter twice for about 15 seconds each time and the 8006 didn’t have any power cutouts this time around. I’m now wondering if maybe the Li-Po battery could somehow be momentarily cutting out or has a bad internal connection. The only thing about that idea though is that the cutouts did occur more often when using the old PCB board and I am still using the same battery. One other thing I have noticed about my 8006 (ever since I bought my 8006 helicopter new) is that I have always had to use around 2/3 throttle just to stay hovering. I don’t know if that is the normal hover power setting for the 8006, but I do know my 8005 helicopter could easily hover using less than ˝ throttle.
I will need to do more flights though to see if doing shorter flights is really controlling the cutouts or I if was flying on a day with less radio interference.

Ray
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Old Oct 26, 2012, 02:06 PM
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Originally Posted by Pilot Ray View Post
Hi Mike,
That looks like a pretty nice battery charger for the Li-Po batteries and the good thing about it is that it can handle all the common size Li-Po batteries plus handle any future bigger helicopter batteries. I wonder if the charging speed is faster than the G.T. Model battery charger.

By the way, the 8005 and 8006 transmitter’s are on AM.

Ray
Ray. I'll let you know it goes with this charger, as I ordered one, cos I would like to see the voltage in each cell, which the GT charger don't do..

Mike..
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Old Oct 30, 2012, 05:54 PM
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Well I got my "tiger moth" tail prop setup today.. Really simple just some sand paper, scissors, and super glue. I didn't really measure anything.. just did it all by eye.. I cut the stock blade down to small stubs and took them down to the width i needed on a belt sander. I cut the tiger moth blade off the center hub just by eye and sanded the corners to fit the stub of the stock prop... then some super glue.. and done. Still need to clean it up with some paint. Seemed to work well. I did some test hovers in my basement (being very careful). I also took apart the main shaft and put some lithium grease on the main gears and the tail motor cog. Vibration is cut down dramatically and it runs much quieter.. also seems to have reduced friction quite a bit as i can feel a difference just spinning by hand.




I took her outside for a quick test.. and unfortunately the charge wires from the battery got sucked up into the main gears and ripped out of the battery, and stripped a few teeth on the gears. Seems to be an ongoing issue with the new battery box model because there is no room for the wires. Anyway I eventually pulled the wires out and she still flew on what was left of the battery and gears. forward speed is now doubled and the reverse is about the same maybe a little faster. I suggest this mod to everyone that owns the 8006. |

I feel I have to keep fixing/ modding this thing almost everyday.. and I've only flown it for 10 minutes lol (:


Cheers!
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Old Oct 31, 2012, 08:20 AM
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Hi Guys,
Finally, I got to fly the modded OS. I ended up using the Motor/gearbox option simply to see if angling the lower blades down at the nose would improve forward flight. It didn't! Without the tail rotor to push the nose down nothing happened though I am amazed at just how stable these helis are.
With the lower blades angled down, as in pic 3, post of Oct 25, 2012, (about 10 degrees) the damn thing just hovered. I was even able to land with this configuration. Same results in reverse.
OS has now been rebuilt to the latest version as I need some flying time.
FYI: Check any new outer shafts that you buy. When rebuilding OS I had intended to use the new outer shaft I had modded to fit the swashplate but found the spacer sleeve between the lower blade grip and the top bearing would not fit (see pic for reason why not).
Ken
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Old Oct 31, 2012, 01:13 PM
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Hi Ken,
I’m surprised that adding lower rotor tilting to the 8006 had no effect on forward movement. I guess the strong upper rotor thrust just negates any direction change of the lower rotor thrust. Maybe you could try making the 8006 operate like the small 4 channel G.T Model helicopter that I have posted a link to below. The 4 channel G.T 5887 helicopter has a fake tail blade on it, but yet it can go forward, backwards, up, down, turn left and right and has sideways flying control. Also, check out the 4 channel transmitter near bottom of the 5887 ad. I wished the 8006 came equipped with a similar transmitter that has all the basic working features like that one, but at same time give the 8006 an extra flying distance safety margin by using a 200 meter control range.

Link to 4 channel G.T 5887 helicopter; http://www.gt-model.cn/Eng/Product_Show.asp?id=162

Also, check out this full size coaxial helicopter; http://en.wikipedia.org/wiki/Kamov_Ka-27

Ray
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Old Oct 31, 2012, 05:43 PM
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Originally Posted by Pilot Ray View Post
Hi Ken,
I’m surprised that adding lower rotor tilting to the 8006 had no effect on forward movement. I guess the strong upper rotor thrust just negates any direction change of the lower rotor thrust. Maybe you could try making the 8006 operate like the small 4 channel G.T Model helicopter that I have posted a link to below. The 4 channel G.T 5887 helicopter has a fake tail blade on it, but yet it can go forward, backwards, up, down, turn left and right and has sideways flying control. Also, check out the 4 channel transmitter near bottom of the 5887 ad. I wished the 8006 came equipped with a similar transmitter that has all the basic working features like that one, but at same time give the 8006 an extra flying distance safety margin by using a 200 meter control range.

Link to 4 channel G.T 5887 helicopter; http://www.gt-model.cn/Eng/Product_Show.asp?id=162

Also, check out this full size coaxial helicopter; http://en.wikipedia.org/wiki/Kamov_Ka-27

Ray
Hi Ray,
It did move forward ever so slowly with the heli horizontal. I'm guessing around 5 feet per minute but that could have been a very slight breeze. Certainly much slower than with the tail rotor working. What amazed me was how stable this thing was in that configuration. When landing I could hover about 6 to 8 inches off the ground (even with ground effect), then slowly back off the throttle and it just settled gently on the deck. I landed this way a number of times just to prove the first landing was not a fluke. It looked good if nothing else.

Setting up similar to the 4 channel G.T 5887 was the original plan and the problem. The original 8006 TX/RX signal coding is for the 8006 set up as is and despite boulier1's assist I still can't figure out either how to change or utilise the existing signal/electronics. Something about old dogs and new tricks comes to mind.

Converting the 8006 to 4 channel and probably 2.4G looks like being the only remaining option but so far I have not found anything “off the shelf” that would handle the 2 x 290 main motors or 14.8 volts. This seems to be the main hang up with the 8006's large size as the smaller helis use 7.1 to 7.4 volts. Also most servos are 4.8 to 6 volt although I did read somewhere that that there are some 12 volt servos about now. Only question now is whether this route would be worth it or I just go and buy something else.

Right now, weather permitting, I'm going to put the modding on the back burner and get some flying hours in.... even if only downwind.
cheers mate,
Ken
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Old Nov 03, 2012, 07:27 PM
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Help help

::Took the 8006 out today and ran it through 3 batteries for almost 40 minutes of test flights. Worked well with the new tail rotor.

I just got it ready for a night flight and the tail motor wont spin. It worked perfectly when I last landed... I checked all the connections.. Fried motor? Fried board? Help please.. I finally got this thing flying and now it's dead again lol
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Old Nov 04, 2012, 12:12 AM
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Originally Posted by helicrapter View Post
::Took the 8006 out today and ran it through 3 batteries for almost 40 minutes of test flights. Worked well with the new tail rotor.

I just got it ready for a night flight and the tail motor wont spin. It worked perfectly when I last landed... I checked all the connections.. Fried motor? Fried board? Help please.. I finally got this thing flying and now it's dead again lol
Hi helicrapter.
It is possible that the extended flight time has caused some problems. Tail motors and their driver transistors don't like being run for too long without a break.
To try:
Disconnect tail motor leads at the board pins and try a 6 volt torch battery across the tail motor leads (NOT the board pins). Polarity don't matter. This will show whether the motor circuit including leads is faulty. Motor will run or it won’t. Connecting 6 volt torch battery directly to the motor will prove or disprove a motor problem. Again motor will run or it won’t. DO NOT have motor leads connected to PCB when trying this.
Check transistors (immediately behind tail motor board pins) for cracking or other obvious signs of being stuffed. Burn marks etc.
Unless you want to remove balance bar and both sets of blades unplug main motor leads from PCB.
Switch heli on, bind TX/RX then set throttle half way. Move forward control slowly on and check voltage across tail motor PCB pins with tail motor disconnected. Should be 14.8 volts or thereabouts. If no voltage the transistors are probably shot.
Ken
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Old Nov 04, 2012, 10:05 AM
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Originally Posted by Trainee Ken View Post
Hi helicrapter.
It is possible that the extended flight time has caused some problems. Tail motors and their driver transistors don't like being run for too long without a break.
To try:
Disconnect tail motor leads at the board pins and try a 6 volt torch battery across the tail motor leads (NOT the board pins). Polarity don't matter. This will show whether the motor circuit including leads is faulty. Motor will run or it won’t. Connecting 6 volt torch battery directly to the motor will prove or disprove a motor problem. Again motor will run or it won’t. DO NOT have motor leads connected to PCB when trying this.
Check transistors (immediately behind tail motor board pins) for cracking or other obvious signs of being stuffed. Burn marks etc.
Unless you want to remove balance bar and both sets of blades unplug main motor leads from PCB.
Switch heli on, bind TX/RX then set throttle half way. Move forward control slowly on and check voltage across tail motor PCB pins with tail motor disconnected. Should be 14.8 volts or thereabouts. If no voltage the transistors are probably shot.
Ken


I tried it again this morning. The tail prop made about 4 complete rotations before it stopped working again.. any ideas of what this could be? anyone have a pic so i know what connection at the board is for the tail?
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