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Old Jan 08, 2013, 05:10 AM
Brent 黑雁
BThirsk's Avatar
Canada, AB, Ponoka
Joined Jan 2012
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Quote:
Originally Posted by tracker1955 View Post
Well, just tried it again, same as before but only wags when hovering, but if I turn left or right it smooths right out. Didn't get any involuntary spinning this time. Will have to keep an eye on it, if it gives me anymore trouble I may have to replace the gear box and motor. If that doesn't work, then a new pcb. I wish I could adjust the gyro some how, it acts as if the gyro can't settle on the right rpm's to keep the tail locked in a hover so it seems like it revs.
Do you have any excessive vibration when hovering. That will often cause the gyro issue.
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Old Jan 08, 2013, 05:23 AM
Brent 黑雁
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Canada, AB, Ponoka
Joined Jan 2012
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Quote:
Originally Posted by BobTopofTheWorld View Post
GRRRRRRRRRRRR my first flight was both EXCELLENT and ... seems the plastic that MJX uses isn't as resistant to cold as I hoped for, a 6 foot drop to the frozen parking lot resulted in death of a tail rotor blade and snapped the rear landing gear strut. (the plastic WLtoys uses on the v911 is EXCELLENT for cold weather)
I know, I know... says 40 degrees f min... FFS thats barely 5 months outta the year here :@
SOMEONE... ANYONE do tell me of a landing gear that will fit AND is cold-resistant.
In the meantime, what method of repairing this type of plastic is best?
I as well broke the landing gear from a hard landing in the cold when my gyro went nuts and sent my Heli into the spin of death. I cut the throttle at about 5 feet so the blades would not be spinning and shattered 3 legs on the gear.
I am going to try Align 450 struts as they won't need much modding to work.
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Old Jan 08, 2013, 05:26 AM
Scotsman in Germany
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Germany, BY, Schwabach
Joined Oct 2012
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Well I've tried it with the cap off - hard to tell if it makes a difference, as having the cap on makes any wobble more obvious due to the diameter.

Played with the flybar a bit and from the following videos, it seems to be pretty straight and level now compared to yesterday's vids. Light quality wasn't very good I'm afraid, but I think you can see that the flybar looks OK.

Put new blades on - no difference whatsoever.

SUNP0020 (0 min 24 sec)

SUNP0021 (0 min 26 sec)


Quote:
Originally Posted by Whizgig View Post
Hi Tigg,
Here ya go: F45 Inner Shaft
Thanks for that Eugene. What exactly are the "blade pins"? All I can see are
- a screw which holds it onto the main shaft, which I managed to tighten about 1/4 turn.
- the pin through the flybar, which is fine and
- the pin which goes through the main shaft and connects the blade holders, which I think is the one. This flew out and nearly lodged in my forehead yesterday when I tried checking the flybar without the blades on (I know not to do THAT again ). It was still perfectly straight and is now back where it should be.

So what do the expert eyes say? On the basis of the flybar seeming to track OK, can I assume that maybe the cap is a bit lopsided and safely fly again, or do I need to somehow check the main shaft?

If a video from a different angle with better lighting might help with further analysis, please let me know and I'll post one up.

Thanks again for all the help guys, and Happy Flying
Tigg

Edit: like this maybe?
SUNP0020 (0 min 48 sec)
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Last edited by tiggertoo1962; Jan 08, 2013 at 06:02 AM.
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Old Jan 08, 2013, 06:17 AM
Brent 黑雁
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Canada, AB, Ponoka
Joined Jan 2012
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Quote:
Originally Posted by tiggertoo1962 View Post
Well I've tried it with the cap off - hard to tell if it makes a difference, as having the cap on makes any wobble more obvious due to the diameter.

Played with the flybar a bit and from the following videos, it seems to be pretty straight and level now compared to yesterday's vids. Light quality wasn't very good I'm afraid, but I think you can see that the flybar looks OK.

Put new blades on - no difference whatsoever.

Thanks for that Eugene. What exactly are the "blade pins"? All I can see are
- a screw which holds it onto the main shaft, which I managed to tighten about 1/4 turn.
- the pin through the flybar, which is fine and
- the pin which goes through the main shaft and connects the blade holders, which I think is the one. This flew out and nearly lodged in my forehead yesterday when I tried checking the flybar without the blades on (I know not to do THAT again ). It was still perfectly straight and is now back where it should be.

So what do the expert eyes say? On the basis of the flybar seeming to track OK, can I assume that maybe the cap is a bit lopsided and safely fly again, or do I need to somehow check the main shaft?

If a video from a different angle with better lighting might help with further analysis, please let me know and I'll post one up.

Thanks again for all the help guys, and Happy Flying
Tigg
From the videos, it looks pretty straight. If you get it up to a low hover, how does it react now.
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Old Jan 08, 2013, 07:15 AM
Scotsman in Germany
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Germany, BY, Schwabach
Joined Oct 2012
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Quote:
Originally Posted by BThirsk View Post
From the videos, it looks pretty straight. If you get it up to a low hover, how does it react now.
Not sure yet, but I know how The Wife will react if I try it in here

Have to try and get out this afternoon and I'll let you know.

Thanks Brent
Fin
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Old Jan 08, 2013, 07:42 AM
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Joined Jan 2013
2 Posts
Hello everyone. I'm new on the RC group site.
I just collected my MJX F645 last weekend.
I am still taking it step by step and tuning the swashplate and trim settings on the controller. I am using Mode 4.
I know it will take some time for me (my first heli since playing with a tiny micro).

I am having a problem with the tail rotor.
When I first started up, the Main / Tail rotors started simultaneously. I had some left/right shifting before takeoff (slowly ramping the throttle).
I toppled over a few times (4 or 5 times) before takeoff and the motors stopped as expected.

Now after restart or full radio reconnect, the tail rotor does not start when the Main starts (usually at 4-5% Throttle), even when throttle ramp up to say 20%.

I can get the tail going with a finger touch of tail rotor.
The tail cannot seem to overcome the starting torque required to roll through that first gear tooth meshing.
Tail rotor seems to run fine unless I the use rudder stick and tail slows to a stop; then the tail can't restart for itself unless it gets a kick start (not always practical!).

The notchiness of the tail rotor gears seem the same as at original (good) start up. Is the gearbox stiffness adjustable?
Could the gearbox or blade shaft or motor shaft be damaged after just a few ground level topples that stop the tail / main blades?

I Did try a little WD40 and then light Royal Purple Synthetic lube on gear box and tail rotor shaft.

Sorry for the long first post. Please advise from your great experience guys.
Thanks.
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Old Jan 08, 2013, 08:15 AM
Brent 黑雁
BThirsk's Avatar
Canada, AB, Ponoka
Joined Jan 2012
1,766 Posts
Quote:
Originally Posted by Hurricane6 View Post
Hello everyone. I'm new on the RC group site.
I just collected my MJX F645 last weekend.
I am still taking it step by step and tuning the swashplate and trim settings on the controller. I am using Mode 4.
I know it will take some time for me (my first heli since playing with a tiny micro).

I am having a problem with the tail rotor.
When I first started up, the Main / Tail rotors started simultaneously. I had some left/right shifting before takeoff (slowly ramping the throttle).
I toppled over a few times (4 or 5 times) before takeoff and the motors stopped as expected.

Now after restart or full radio reconnect, the tail rotor does not start when the Main starts (usually at 4-5% Throttle), even when throttle ramp up to say 20%.

I can get the tail going with a finger touch of tail rotor.
The tail cannot seem to overcome the starting torque required to roll through that first gear tooth meshing.
Tail rotor seems to run fine unless I the use rudder stick and tail slows to a stop; then the tail can't restart for itself unless it gets a kick start (not always practical!).

The notchiness of the tail rotor gears seem the same as at original (good) start up. Is the gearbox stiffness adjustable?
Could the gearbox or blade shaft or motor shaft be damaged after just a few ground level topples that stop the tail / main blades?

I Did try a little WD40 and then light Royal Purple Synthetic lube on gear box and tail rotor shaft.

Sorry for the long first post. Please advise from your great experience guys.
Thanks.
If the tail seems to run ok after you spin start it, it may be the motor has shifted on the mount. There are 2 screws that hold the motor. Loosen those and retighten. Also, check the mount for cracks. The tail should turn pretty easy. Also, if you are testing on carpet, check for fibers in the gearing. It likes to wrap around the shafts. Animal hair as well binds things up.
If everything runs smooth, check the gyro on the pcb to make sure it is not broken loose.
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Old Jan 08, 2013, 10:05 AM
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Joined Dec 2012
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Take the blade and cover off the tail motor and run up in your hand watching the mesh of pinion gear with main gear, see if pinion wobbles. Mine was bent from factory and had to straighten.
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Old Jan 08, 2013, 10:41 AM
Scotsman in Germany
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Germany, BY, Schwabach
Joined Oct 2012
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Quote:
Originally Posted by BThirsk View Post
From the videos, it looks pretty straight. If you get it up to a low hover, how does it react now.
Thankfully the rain stayed away long enough for a test flight this afternoon. It was a bit windy, so it took a while before I got around to doing any hovering close in - that's my excuse and I'm sticking to it .

Not really knowing the heli too well yet I can only say that it seemed to fly OK, and I don't see anything obviously wrong when it's in hover. If any of your more experienced eyes notice anything untoward I'd appreciate it if you let me know.

Meantime I'm quite happy to fly the heli as is, since I now have #2 on the way and, should anything happen to Big Bird here (The Wife has insisted I name them all so she can follow what I'm talking about ) I can always use him for spares.

Thanks again
Tigg

test flight after repairs (10 min 7 sec)
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Old Jan 08, 2013, 11:45 AM
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United States, OR, Portland
Joined Oct 2012
674 Posts
Quote:
Originally Posted by tiggertoo1962 View Post
Well I've tried it with the cap off - hard to tell if it makes a difference, as having the cap on makes any wobble more obvious due to the diameter.

Played with the flybar a bit and from the following videos, it seems to be pretty straight and level now compared to yesterday's vids. Light quality wasn't very good I'm afraid, but I think you can see that the flybar looks OK.

Put new blades on - no difference whatsoever.

http://www.youtube.com/watch?v=vV1pDKI_TdQ
http://www.youtube.com/watch?v=bb0zKvrIzf0



Thanks for that Eugene. What exactly are the "blade pins"? All I can see are
- a screw which holds it onto the main shaft, which I managed to tighten about 1/4 turn.
- the pin through the flybar, which is fine and
- the pin which goes through the main shaft and connects the blade holders, which I think is the one. This flew out and nearly lodged in my forehead yesterday when I tried checking the flybar without the blades on (I know not to do THAT again ). It was still perfectly straight and is now back where it should be.

So what do the expert eyes say? On the basis of the flybar seeming to track OK, can I assume that maybe the cap is a bit lopsided and safely fly again, or do I need to somehow check the main shaft?

If a video from a different angle with better lighting might help with further analysis, please let me know and I'll post one up.

Thanks again for all the help guys, and Happy Flying
Tigg

Edit: like this maybe?
http://www.youtube.com/watch?v=YDfJ1...ature=youtu.be
The flybar seems good. Not sure if I'm seeing or hearing correctly, but there may be a slight wooble in the shaft and I hear a bit of what I would call clicking. Both my F45s have no woobles and just the normal gear noise. If you are happy with the flight, just check for changes in shaft movement and gear noise. Any woobles will probably get worse as the bearing wears. BTW, woobles can be checked by keeping the chopper stationary (bolted down), then from above placing a stiff wire with a 90 degree angle (an L shape) in it straight down near the rotor head. The tip of the wire is placed just above the center of the shaft with a tiny bit of white paint on it. Any woobles can be seen very easily.
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Old Jan 08, 2013, 11:46 AM
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tiggertoo1962
Forgot to mention. Any missing main gear teeth?
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Old Jan 08, 2013, 01:57 PM
Scotsman in Germany
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Quote:
Originally Posted by hawaiichopper View Post
BTW, woobles can be checked by keeping the chopper stationary (bolted down), then from above placing a stiff wire with a 90 degree angle (an L shape) in it straight down near the rotor head. The tip of the wire is placed just above the center of the shaft with a tiny bit of white paint on it. Any woobles can be seen very easily.
Hey Hawaii.

All teeth present and correct sir! Tend to agree with you about the clicking now I listen again. Didn't have a healthy one to compare it to so probably convinced myself there was nothing to it. Hard to be objective when you just wanna get back in the air .

Trying to visualise your tip with the wire, but I'm either too dumb or still too tired from the night shifts. Think you could be just a bit more specific about exactly how it works (placement of the wire? length of the "L"? wire running inside the shaft or outside for a comparison? where the paint comes into the equation?). If you have it, either a vid or a diagram of the test would be great... or a link if you've seen this somewhere else.

Thanks once again bud
Fin
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Old Jan 08, 2013, 03:19 PM
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United States, OR, Portland
Joined Oct 2012
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Quote:
Originally Posted by tiggertoo1962 View Post
Hey Hawaii.

All teeth present and correct sir! Tend to agree with you about the clicking now I listen again. Didn't have a healthy one to compare it to so probably convinced myself there was nothing to it. Hard to be objective when you just wanna get back in the air .

Trying to visualise your tip with the wire, but I'm either too dumb or still too tired from the night shifts. Think you could be just a bit more specific about exactly how it works (placement of the wire? length of the "L"? wire running inside the shaft or outside for a comparison? where the paint comes into the equation?). If you have it, either a vid or a diagram of the test would be great... or a link if you've seen this somewhere else.

Thanks once again bud
Fin
I'll attempt a picture but I'm no artist! Hopefully it will make sense.
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Old Jan 08, 2013, 03:44 PM
Frank
Germany, BW, Heubach
Joined Dec 2012
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Quote:
Originally Posted by tiggertoo1962 View Post
Hey Hawaii.

All teeth present and correct sir! Tend to agree with you about the clicking now I listen again. Didn't have a healthy one to compare it to so probably convinced myself there was nothing to it. Hard to be objective when you just wanna get back in the air .

Trying to visualise your tip with the wire, but I'm either too dumb or still too tired from the night shifts. Think you could be just a bit more specific about exactly how it works (placement of the wire? length of the "L"? wire running inside the shaft or outside for a comparison? where the paint comes into the equation?). If you have it, either a vid or a diagram of the test would be great... or a link if you've seen this somewhere else.

Thanks once again bud
Fin
here is what I think he means tig
take off the blades first.
tell me if ya can see what i mean and I sent you a message too

Frank
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Old Jan 08, 2013, 03:45 PM
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The "white dot" end of the wire is placed over the center line of the rotor shaft. You can then observe the shaft movement from on top (looking down) and from the side. Of course ensure that both the wire and the helicopter are static and can't move at all. I attached a chopper to a piece of one meter square plywood that had a wood frame on top from which the wire was suspended. The wood was held by two bags of concrete mix I had in the garage. Probably overkill, but nothing moved! Click on picture to see text.
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