RC India

Hi to all,

Yesterday evening, In my flight, some small crashes (no physical damages) and then I tried to take off again.

The heli rotates along with the fuselage and also it does not take off. I was trying all my possible ways but I could not.

Can anyone suggest me how to fix this issue? Please check the video below.

http://www.youtube.com/watch?v=K2rdRnkscvI

Try adjusting the "GAIN" and "PROPORTIONAL" controls on the 4-in-1 unit on your heli. Start with the "GAIN" one.

how to do this anwar?

There is a 4-in-1 controller unit on these Eky helis (like Robbins, Lama etc).  It is a white rectangular box, and you will see two small "pots" marked "Gain" and "Proportional" which can be rotated with a small flat screw driver.

You can see them in the link below (the two holes with a while line/cut). Insert a small screw driver, and turn the "Gain" one very lightly (something like 5 degrees each time), and test fly it.  If it got worse, turn in the opposite direction. Do it step by step. The final tuning is done using the PROPORTIONAL one.

http://www.rc711.com/shop/product_info.php?products_id=53

Sriharishine,
Forget about taking off. First try to get the proper tail control. I am not sure about this heli, but i think that maybe the gyro is reversed ? Or tail blades put opposite or maybe belt put the otherway.

Not sure this was of help, but i couldnt resist posting.

BTW good to see you trying to fly something !

I have tried changing the gain first, no change, it was as it is before.... And tried with proportional too. .... No change in the condition.... Still it is rotating with the fuse and not taking off

Then the gyro must have gotten reversed. How bad was the crash and what all did you have to fix / change ?

maybe you put the servo the other way ? I thought i could do this and potentially reverse the setting. maybe that was the case here ?

More than the servos, may be one of the motors was connected in reverse after the crash ?

Note that on most of these helis, the "gyro" function is done by the coax blades, and the servos are only for the swash.  That is why I was asking if any motor connection came loose in the crash.

The crash is not big one, I have not disconnected or connected anything, SO there wont be any chance for reverse, but to confirm, the switched in the radio (Rud, Thrtl, Ail and Ele) all are in the normal mode (not reversed mode).

And also the fuselage vibrates(like shivering) when I increase the speed.

can you also tell me the initial settings that would be right to fly it?

I have tried the Gain and Proportionals which does not reacted.

Please tell me how to reverse the settings, I will do it...

Thanks

The solution lies somewhere between [1] adjustments to the Gyro/Proportional pots, [2] making sure the motors are not reversed, and [3] adjusting the "rudder trim" slider on your transmitter.

You should be able to find the stability using one or a combination of above factors.  Remember that a small adjustment goes a long way while doing [1] above.

And if none of these helped, then the 4-in-1 unit may have gone bad :(  They are sometimes known to go bad if it tried to move the blades but the blades could not move (due to crash or being pinned to the ground etc).

Here are two related threads.

http://helifreak.com/showthread.php?t=111535

http://www.helifreak.com/showthread.php?t=140621&highlight=proportion+gain+adjustment

Yet another reason that someone pointed out is when the screws that lock the gearwheels to the shafts have gone loose. Please check those also.

Srihari,

Please ask the person from whom you got this heli may be he encountered  such problem earliar and might be able to help you

Rest all possible things have been covered in the above posts just make sure that the trims on the Transmitter are centered and the battery is fully charged

Hellyflyer

Hi Amit,

Thank you amit, I will contact him for this issue, In  the meantime, I am also searching for a person who fly this model and so he/she could recognize the problem and come up with the solution.

I fly a similar coaxial model Esky lama v4. I had similar issue twice and for once the culprit was the servo linkage that guides the tilt angle of the lower blade was broken (in short the swash does not move up or down). Second time it was that the the 4-in-1 mixer control was bad.

I also have exactly the same problem with my small palm sized model art infra red heli. I thought the batteries have gone weak. But even after changing the batteries, same problem.

Earlier I had faced a similar problem, but heli used to take off ateast. It used to get sorted by changing the trim setting on the TX. It was a very fine setting though. However recently, the setting does not have any effect at all. the heli does not even take off..  :banghead:

maybe another 1,000 bucks for a new one.  ???

So there is no solution for this issue???

Anyone there who can fix this issue for us???

Well there sure is some solution... but first we need to identify the cause of the issue. Is it possible to post close up pictures of the heli with the canopy removed? Given that it is a esky heli all parts can be purchased and replaced if the faulty part is identified. The issue could be as simple as one of the servo wire is loose. Both the motors seems fine as both blades rotate. Given that you have not made any changes I can only suspect the servos and the servo linkages

Does the heli stop spinning or the rotation slow down when u apply yaw in the opposite direction of rotation?

yes, We are nearing to the issue, If I apply yaw in one direction then the rotation speed is increased and when I apply the opposite yaw, The speed is decreased but rotates in the same direction...

How can I confirm that the Wire to servo is loose, Since the both servo works as per instruction of the tx?

Ok so looks like either some linkage contorlling the swash is broken or the 4-in-1 controller is not functioning. Does it blink a red light on the 4-in-1 controller or is it solid green. Did u happen to change blades. It may sound stupid to ask as you have said u have not changed anything. But inter changing the blades A and B will cause the heli to spin and not fly ... so just confirming... Pls try to post some close up pictures if possible

I haven't changed the blades before, but after getting into this issue, I though that blade may be the reason for this problem and so I changes but after changing there was nothing different. Yes after switching on the Tx, the 4 in1 system shows solid green. Still I can say that I have not changed anything before this problem arise.

And I will be posting the closeup pics by removing the canopy by tonight, can you say "How can I find whether the" Linkages controlling the swashes are broken or not?"

Just went through the entire post... seems like anwar, gaurav and others have already walked you through the list of things that might be wrong.....  I will go home play with my lama try some scenario by unpluging servos and test.

Regarding the linkage: Basically they pop off on these helis just like the flybar. They dont break unless the crash is really hard. I will try positing some pics on tonight. But cant gurantee...

Also when u said u changed the blades. Even thought all 4 blades look similar the lower blades are different from upper blades. So please double check that u have not swapped them. 

I copied the picture for an on sale message. Verify that the linkage has not popped off. I have rounded the linkage in red. Not sure how visible the pic is...

I am sure that these linkages are fine...

While removing the OLD blades, I have marked them out so I can replace it to ensure that the blades are not interchanged.

And I will be posting the close up images removing the canopy by tonight once I reach home...

Dear Srihari, how hard was the crash, the linkages were fine when i sent them to u and as u yourself had mentioned u flew it once right, try sending more information with pics maybe i can see something amiss.sorry could not reply earlier as i was not in town

Vijay, When you send all where fine and good in condition and it flied well. A small crash, the heli fell down from 2 feet height that is the crash actually. I will post the close up pics by removing the canopy today...

Dear Srihari, good to hear it flew well, i am still waiting for the pictures, if any of ur friends are interested kindly refer my name as i still have the EC-135, Big Lama, Falcon 400 3D heli and belt cp heli fo e-sky.

Please check the close up pics and help me out to find the problem and to fix them to fly the heli.

more pics

some more pics goes here

Can anyone help me out to fix the problem with the above closeup pics?

If anyone can do it, Then I am ready to send it to you for fixing and then you just fix and resend, I will bear the shipping cost for them... Coz it is idle here...

Hi...looking at the pictures I do not see any physical damage to any of the servo linkage or the blades. Only other suspect is the 4-1in-1 controller....

 

Yes, I also, but one more thing that I suspect is the Shaft that connect the lower blade and the motor which is fixed on the frame through bearings, If there is struck in it then it would let the fuse to rotate right
?

And also, Shall I completely disassemble and then re-assemble the heli ? Is that right choice to fix this issue?

May be ...may be not... I still think the cause is the controller.
In co-axial heli the lift is generated by the rotation speed of the blades, as long as both sets of blades are spinning at exactly the same speed the heli can lift straight up.
The yaw is controlled in coaxial rc helicopters, by making one set of blades spin faster or slower then the other set.
So either the teeth of the rotary system might have been broken. From the image it looks fine... but check the inner rotary wheel.

the wheels are perfect and none of the teeth is broken.

And for you information, I have tried a experiment by removing the top blade set and run the heli, When I increase the throttle, the same happens - the fuse rotates. So the condition is same even after removing the top set of blades then what would be the suspect?

I think we have two option,
1. Shaft of the lower blade
2. 4 in 1

AM I RIGHT?

The fuse is suppose to rotate when one of the blades is not rotating or not present... that is the normal behaviour. It should basically rotate on the direction of the blades is rotating. So only other suspect is that the 4-in-1 contorller might be bad

 I have completely disassembled the heli to find the exact problem in it, And found that one teeth of the main wheel of lower blades axis is broken and rest are fine...

Is this is the only problem for the rotation of the fuse???

Please let me know as soon as possible.


Srihari

hi mate,
check that 'both the shafts' are straight and that the blade holder is a firm fix on the shaft......sometimes the top blade holder comes loose from the shaft......it this is so and it is the plastic one sometimes can be fixed with 'ca' glue....super glue.........the lower blade holder is fixed by the little screws......they go into holes in the shaft................. also check that the gears are fixed tight to the shaft... these are the things that cause your problem........
the contoler bad...usualy it stop one motor when bad.
your blades and servo conecters look fine to me......
one tooth missing ...you need new gear there realy, but should work, but may cause 'clicking; noise
 make sure the gear on the motors are firm also.
regards
don

Thanks don, The shaft has no bent at all... but the holder of the top blade is loose as you said, I am going to fix it by gluing it.

And for the wheel, I am not sure whether to get it but I think I can fix it using MSEAL and a nice file....

Thanks for your comment and waiting for more comments.

if you hunt around ebay.
seasrch for lama upgrades.....there is a ally top for that shaft with a grub screw fitting..........you could also then put a 15mm nonger shaft in to help with blade clashes.
http://shop.ebay.co.uk/?_from=R40&_trksid=p3907.m38.l1313&_nkw=lama+upgrades&_sacat=See-All-Categories
there seem to be none at ebay india but some from aisa may not be bad for you.......these all fit the robins etc, same basic heli but different frame set
regards
don

"blade holder is a firm fix on the shaft......sometimes the top blade holder comes loose from the shaft......it this is so and it is the plastic one sometimes can be fixed with 'ca' glue....super glue."

Was about to suggest this, as I had an identical problem with my Syma Scweizer 300. Since you had a minor crash, this is most probably the damage that is causing your fuse to turn and resulting in no take off. I CA'd my Blade holder to the shaft and all was well after that.

Shrikant, your infra red heli has probably lost a stabilising weight from the tips of the  blades that are mounted above the main prop. Use M seal to re create the weight and all should work well.

Btw, Sriharishine, you need to change that gear with a missing tooth.............

Cheers!

VC

hi mate,
one thing to watch for when buying spares for these .....
there is a difference in the outer shaft..... there are two versions one has holes for the lower blade holder at a different position to the other outer shaft so be sure to get that shaft for the robbins all other blade assosiated spares fit all the lama type heli from esky.
also the 'extreme blades' are very good and stronger than the black stock ones.
if you find it 'easy' to fly then shorten the flybar  (with the weights on)  by about 10mm each end........this must be exact mind or it will upset the heli instead of making it more reactive

regards
don