V977

23 May 2016

I flew both heli on 20 May 2016 and decided I have enough for now. I will make and fly airplanes instead.

16 May 2016

When the rudder became twitchy, when it would held its direction then gaves up and then tried to hold the original direction again, I was afraid I have a faulty receiver board. But when the other helicopter behaves likewise, then I suspected it was my transmitter again.

I had re-soldered the rudder potentionmeter twice; could it be my soldering skill be that bad? I opened up the transmitter and found the culprit, a red wire has broke loose. Not a problem, a bit of soldering cures it. The last two soldering exercises were with the white wire. I flew perhaps 18 flights over the weekend.

26 April 2016

I flew 14 flights last Saturday, 23 April 2016. The night before, I have replaced the main gear to the older V977 because I want to fly that, to use up any batteries that cannot fit in the newer V977. I crashed it once and noticed that the main gear was still on the main shaft, but 2 spokes of the main gear was missing! I flew it again, missing 2 spokes.

I can do normal flying at 3D+idle up mode on both heli.
On 6G, I practiced pirouttes (occasionally I get one or two round of nose-in circles), backwards flying and some 'wing-over' (whatever it is called with heli).

Last night, 25 April 2016, the $27.57 for the 4 batteries and charger arrived. I bought it for 2 reasons.
1) The 4 batteries, knowing that there is a current freeze on Banggood to Singapore lipo delivery but since I can still order this item from Banggood, well...
2) The charger that claims
"1-to-4 large current charger charges 8 times faster than regular ones. In this way, it only takes 72 minutes to charge four 520mAh batteries. With stable performance and high charging efficiency, you can rest assured to rely on it. And it is easy to use."

And now I have 14+4 batteries!

18 April 2016

Repairs again

On Saturday, a crash had the tail motor came out of its housing. It was inserted back in and it works fine. That afternoon I disassemble the blade holders (clips as WLToys call it) to access the bearings. I also noticed the bearings were all arranged with the sealing piece external to the holder surfaces. This is counter to what I thought it ought to be, so I re-align them and inserted a spare bearing to replace the broken one. I used blue loctite threadlocking compound on the small screw in the horizontal shaft to prevent fly-offs and dabbed some on the tail motor for insurance.

The canopy was missing three grommets. The forward left pin (motor side) broke when I attempted to straighten it, so I only had two to insert. I used a tweezer this time and it works well. The rubber grommet was squeezed with the tweezer and inserted one end into the canopy, including the tweezer. Then the tweezer was withdrawn, leaving the grommet midway in the canopy hole. Finally, the grommet was coaxed to its seated position bit by bit. Since I already have the threadlock at hand, I dabbed some there for luck.

Out of the nine batteries I brought to field yesterday I couldn't connect three, I think I may have to solder a different battery connector to the receiver board.

Flying

The wind has subsided and the heli is easier to control.

I practised spinning (pirouetting?) left and right slowly. Then I introduce some aileron control to make the heli go in one direction and then the other while spinning slowly. Another one I did is to introduce some elevator control instead of aileron. By timing and controlling the inputs I was able to make the pirouetting heli go round in circles and by limiting the amount of rudder and pulling back the elevator, tail-first flying with left and right banking turns. I think this is a useful exercise and my flights in the immediate future is going to compose of lots of this pirouetting around.

4 April 2016

I couldn't use up all my batteries on 27 March 2016. Both of my V977s' tail rotor will speed up with the main motor motionless unless the throttle is very high.

Adrian thought it was board failure, motor kaput, Chris thought it is battery dying. To both I questioned how possible is it with two heli having identical symptoms? Mr. Tan supposed it is transmitter problem. I thought so too, so I changed the batteries in the transmitter but that didn't work out. He then suggested opening up the casing to check for wiring to the joysticks.

I had ruled out the rudder wiring to the joystick because I re-soldered it once and that time, the tail rotor didn't spin. I opened up the casing and found that the white wire was indeed disconnected from the rudder potentiometer and it seemed it has been brushing itself to the throttle's potentiometer!

This time round, I exposed a new length of the wire core before soldering it to the rudder potentiomenter at the joystick. It works and I hope it will last.

With the transmitter repaired, I flew 10 batteries last Saturday on my two V977s. Only the newer V977 can do flips, the older one keeps slipping the main gear and so is relegated to 6G flying. Tan suggested loctite on the main gear, I think I will take up his suggestion.

Flips: Forward, Backward and even Sideways; I have a better success rate now. Every flip happens so quickly that before my reaction catch up, it's over.  Perhaps with more anticipation and automatic-reaction I might be able to do tic-tocs one day. In the meantime, it's untidy flips.

I also tried loops. They are all untidy and occassionally the V977 got too low for comfort.

Tail-first flying is difficult even though they were attempted on 6G. I am still doing round circle circuits. The circle has to be large, a bit too tight and the heli's tail swings back into the head-first forward flight mode. It wasn't because the CG is wrong, I think it was because the tail's rotor is acting like a forward fin, but Mr. Tan says that's neglible. Maybe that's true for his good-size heli, but I don't think that is the case with V977. Mr. Tan confided he has problems with tail-first flying too, that sort of made me feel better. hahahhha....

I think my bad performance can be blamed on the gusty winds and that the heli is too small rather than admitting it could be my not-so-acute reaction. I don't suppose I can react quicker, but when my anticipation gets better, (and the wind slackens), I think my flips, loops and tail-firsts can become more presentable and then I can perhaps progress to tic-tocs.

My newer V977 has developed great slop at one of the blade clips, I can wiggle it around. I think a bearing there is probably busted. This was a familiar experience, as concluded in my 14 October 2015 entry that "Slop was due to damaged ball bearings". I shall use loctite to assemble the horizontal spindle and screws to prevent fly-outs as per my 11 November 2015 entry.

So I shopped at Banggood for the horizontal spindle and screws, the blade clips with bearings, the soft bushings and conical washers, main gears (6 pieces!) and came to notice that a WSX 4x520 mah combination package ships to Singapore (not other combinations). Immediately I placed my order for all the above! Why do I need more batteries? That's because I have noticed last week that Banggood is not selling/shipping lipos to Singapore. I have also noticed that our local hobby shop, Rotor Hobby, does not sell these batteries even though they sell the XK K110 which apart from the board, I read, is identical to the V977. The WSX combination also said it can charge 520mah battery in 70 minutes which sounds like a good deal, so I placed my order for the combination and all those parts I require (didn't bother to check if I already have some of them at home) and if Banggood can't deliver, I am prepared to apply for refund for the WSX combination if it can't be shipped.

20 March 2016

When the V977 spins on power, it may not be the gyro. I replaced the tail rotor and all's well again.

I got my courage up and did some flips and hammerheads today on idle up. They were very untidy but you can see what they were to be.  I tried inverted for a short while and crash very soon. Maybe it's the wind.

At least I am now capable of flying figure 8 in 3D mode.

 

15 March 2016

It seems that flying the V977 improves my flying ability in general.
I received my CX-10A quad and I can fly it very well now. It could be that they had programmed it better, but I think flying the V977 helps a great deal.

7 March 2016

I attempted to fly with idle up and the experience was getting frustrating. Many flights later, I found I can handle idle up. Infact idle up, regardless high or low, is easier to handle then 3D low!
But this is all relative, no way as easy to fly with 6G of course.
My idle up flying is now in the figure 8 stage now.

One day I was surprised that both heli did not react to the transmitter. Then I realised that the transmitter's 4 batteries are weak, even though the LCD shows 2 bars remaining. Replacing the 4 batteries and all's fine again.

Yesterday a heli hopped and I couldn't get it to fly. I replaced it's main gear and it's fine again.


I only have the 10 new batteries now.

9 January 2016

To the left is the 3rd V977 and at right, the 2nd V977. I noticed that the main gear of the 2nd V977 was not as deeply set as the 3rd V977 (red circle). Flights this morning confirmed this. It require more throttle to hold level.

On the 2nd V977, the main gear was loose and showed heavy wear anyway, so I replaced it with a new one. Still, for unknown reasons, the main gear could not be set as deeply as the newer 3rd V977 despite my attempts. I also noticed that the front elevator socket has cleared the ball joint and was at the arm. At 3D Idle up (throttle hold of course), the blades are level with the throttle stick high.

 I lengthened the 3 pushrods by a full turn and made sure that the front elevator socket is correctly mounted onto the ball joint (red circle).  At 3D Idle up, the throttle stick is near middle.

At 3D Idle up, the adjusted 2nd V977 is now similar to the new 3rd V977.
Test flight has shown this works, there is more lift at 6G mode with the throttle stick slightly high. I then fitted 3 rubber grommets to the canopy (the first V977 but used on the second V977) and set them with superglue.

Most of my older batteries are puffed and I suspect less power/capacity is available. I don't run them down until the motor shows sign of slowing and I set my timer to 5 minutes for each flight. Sure, maybe the motor is drawing too much current, but there's nothing more that I could have done then limiting the flight time. I suspect charging might at least be part of the cause of puffing. So far, I have been charging them with the WLToys' USB 4-way individual charger (although the 4th socket seems not to be working now).

To the left is the mentioned WLToys' USB 4-way charger. On the right is a set of USB charger and 1-to-5 charging cords.

Since I have now three sets of USB chargers and 1-to-5 charging cords that came with my purchase of batteries, I charged the 10 new batteries with them.

• Unlike the WLToys' USB 4-way individual charger which has 4 LEDs to indicate which battery is charging or has completed charging, the USB charger only has 1 LED. If one of my battery will be damaged in the future, I don't know if the USB charger will continue to charge and therefore damage the other batteries.
• The WLToys' individual LED lights up when it is charging, but if a battery is removed or the charging is completed, the LED is off. Whereas the USB charger's single LED will only light up when charging is completed or when no uncharged battery is connected. Obviously the WLToys' charger is more convenient and I would be able to identify the damaged battery.
• The USB charger took a few hours to charge the 5 batteries at a go. I left the chargers working overnight and my batteries were charged in the morning. This is much longer than when using the WLToys' charger, the batteries were usually charged in about an hour. Perhaps this means that the USB charger is only capable of charging at a much slower rate and this might prolong the life expectancy of my 10 new batteries.
• I have noticed that if I plugged in a single battery to the USB charger, the charging is completed rather quickly, quite similar to WLToys'.

Taking two helis to alternate in order for each of them to cool down before the next flight is a bit troublesome and waiting is killing time, so I searched the web just now while watching Vasantham for the question whether it is alright to fly back-to-back continuously.  Some said letting the motor cool is applicable only to brushed motor and not so for brushless, others said that the components reached their peak temperature within a minute or two so it doesn't make sense to let them cool. I think that makes sense, and I shouldn't need to rest the heli between each flight. Then I saw a link on batteries. Some recommended that in order to have the batteries last longer, the used battery should be rested for about 15 minutes before charging, and when fully charged, the battery should not be used for flight for about 15 minutes so that the chemical can stabilize and that the batteries should not be stored fully charged for weeks, they should only be about 50% capacity for storage (which I wouldn't be able to set unless I use my proper charger)rather, and each use should be limited to 85% capacity, and as voltage drops, the current increases and thus leading to heat.

Taking all these into consideration, I shall charge my batteries the night before flying day using the USB+1-to-5 charger, fly my heli for 5 mins each flight, no cooling period in between flights, and the discharged batteries kept until the night before flying day for charging. The 5 mins ought to use up 50-85% capacity.

17 batteries @ 5mins each = 85 mins. I think I would be tired from flying so long!

8 January 2016

Order for a bnf (packaged with 5 batteries) was placed on 29 November 2015.
The goods finally arrived on 7 January 2016; 39 days or almost 6 weeks.

I tested this 3rd V977 immediately.
I did a short indoor flying and it reacted normal (6G mode), except that this heli is so much louder.

And now my total battery count is 17 after misplacing a few of them? I think I will mark the brand new batteries separately from the older ones.

30 November 2015

I was flying fast forward at 3D idle up Low mode at the field opposite the swimming complex.
Wind was blowing, field was unfamiliar, heli was too small, 3D idle up was exciting, etc.
My 1st V977 ended up in a tree which was full of branches and leaves. I couldn't see it but I could hear the motor spinning.
Boh bian, buy another bnf V977.

<--- V977 somewhere inside.

27 November 2015

Bought 5 more batteries, they may come before Christmas. I will have 13 batteries then.

I list below what I think is the flying progression:

1. Hover and pirouette in all orientation
2. Forward in straight, figure eights, slow, medium, fast
3. Backwards in the different paths and speed as in Forward
4. Loops in forward flights, then backwards
5. Rolls in forward flights, then backwards
6. Flips are only from hovering
7. 7 to 12 are 1 to 6 as above but inverted

Now I am good in 1.
Getting better in 2, need more practice to get symmetry.
Started out in 3, need a lot of practice.
Didn't try 4 to 12.

V977 is cheap and good. I have managed to get good return for such a low investment.

I started with objective 1 by doing it in 6G low mode, then high mode.
Then proceed to objective 2 by doing it in 6G low mode, then high mode.
When comfortable, I went back to do objective 1 and 2 in 3D low mode, 3D low mode+idle up and finally 3D high mode+idle up.
With objective 3, I am still in 6G low mode. I need to become more comfortable before I progress to idle up.

22 November 2015

I practiced with flight simulator to practice generally, including tail-first and also to figure out how to fly with 3D idle up mode. I tried my 2nd V977 on 3D idle up low and high rate, seems fine now. High rate requires more correction, i.e. moving the sticks the other way momentarily. I can do some ugly figure 8s on 3D idle up High rate and recover for hovering. I ought to be able to try inverted if I had a bigger and more isolated flying area. Seems I have got the heli flying done with and it is only a matter of practice for the different maneuvers. I have now come to the limitations of the V977; I could appreciate a 'better' heli now, one that is bigger and has more power.


Heli flying is quite similar to plane flying except: 1) heli can fly backwards, and 2) lift direction can be changed immediately (most noticeable with idle up when the throttle stick controls the collective pitch). And of course, the V977 can't glide power off. Glad I didn't buy a third V977, maybe I might need more of the big gears and more batteries (the one that came with the RTF has no power now so it must be damaged).


My interest has waned, but the two V977 are good and I will use them for occasional flying.


On Sunday morning my 2nd V977's tail gyro/mems/whatever is called, was damaged, so I flew the 1st V977 in the evening. Before flying it I noticed that the main gear was missing a few teeth, so I replaced it but before it was replaced, I sprayed on EZglide to the main gear because I think it helps. Flights were good, once you get the groove. Left circles are easier than right circles.

16 November 2015

I use 6G low mode for my practices. For tail-first flying, I am starting with the heli higher then normal and at a bigger field. I will reduce the height and field size when I am comfortable.
I didn't fly on Saturday and Sunday wasn't a good day as I was dizzy. I only put in 3-4 flights last Sunday. I let Mr. Wong flew one battery, he crashed and resetted about 8 times while doing hovering; the wind was a bit strong. I brought both V977 to alternate, and so did not have to wait for the motor/esc to cool down, but still ended up with plenty of rest in between because of my dizziness.

11 November 2015

On Friday night, I assembled the rotor head onto my 2nd V977. I gave it a slow start up but the blades flew apart again. I couldn't find one conical washer. Lucky I found one in my spares bag.

On Saturday afternoon I purchased this small bottle of Loctite. I smeared a bit of it on a screw and installed the screw onto the feathering spindle. After I assemble the rotor head, I removed the last blade holder to expose the internal thread of the spindle and used a small piece of stick to smear some Loctite to that end of the spindle and then assemble the head and tighten with the remaining screw. I did it this way because I was concerned that if I had applied the loctite to the screw, I might need a few attempts to fit the screw onto the spindle and in the meantime contaminate the bearing causing it to seize. I found that after the screws were tightened, the blade holders do not move in a free manner and yet if I do not tighten the screws, a screw would fall out. So I put it as new rubber grommets and tightened them anyway. I hoped that the servos have enough torque to overcome the tightness and the rotor head will be alright after it has been 'set-in'.

The 2nd V977 was left alone until Monday for the Loctite to set. My fear of too tight a rotorhead did not materialise and it has had more than 10 flights since, and so I would say the replacement is a success.

I chose 6G for most flights, backwards (tail-first) flights got better and I did a better controlled inverted flight except that I crashed it when I couldn't flip it back upright and the heli drifted too far away to see. Crash was ok, no parts needed replacement. For the last 2 flights of this 2nd V977, I flew it with 3D on low mode and seems to get better.

I think my flying has improved without me realising it and it was simply because of practice. With more practice I got more and more familiar with the different orientation of the heli and the control inputs. I shall practise in 6G low mode for tail-first flights and practise hovering in 3D low mode.

6 November 2015

The main shaft and bearings arrived on the evening of 2 November 2015. Actually I had all the necessary parts to replace the damaged pitch servo and to assemble a new rotor head on 23 October 2015 if I re-use the main shaft and bearings, but I have been procrastinating. The servo should be replaced before I do up the rotor head, so I did just that last night.

There are two screws to remove before the servos clamping piece can be taken out. Perhaps  Banggood item SKU122853 can fit V977, Banggood says so but the photos look different from my recollection. The first screw is highly visible, it has its head exposed and I thought that was it until I found I couldn't prise it out. The second screw is behind the swashplate guide rail, it is quite easy to gloss over it, but it is there, the clamping piece has a sort of tubular recess that concealed the screw head, leaving only the top visible and accessible. I pried open the zip tie with a small spectacles screwdriver and removed the damaged servo. The new servo's servo lead plug was then fed round the main shaft, and plugged into the receiver. Finally, the clamping piece was re-fitted, making sure that the swashplate's rear guide arm is in the guide rail's slot, and I zip-tied the wires. I set the throttle to 50% (I tried 6G, 3D and 3D+idle up) and mounted the servo horn at what I think is the same position as the other 2 servos. This setting up was done with throttle-hold activated of course.

Next up, I shall assemble a rotor head from all-new parts (rotor head, rubber grommets and conical washers, blade grips with bearings, feathering spindle and screws, blades) onto my 2nd V977.  Hopefully this time, the blades will not shoot out when flying.

2 November 2015

On one occassion I managed to get the heli in 6G mode to go inverted. It was as stable as it was in upright. It was fun because of the novelty but I know I shouldn't because I was not ready. I could also fly the heli downstairs, but with people around I have to be very careful, so although it was comfortable, it wasn't suitable. Heli flying is still interesting but I can see it is a very long process.

I can now perform the following with competence, all in 6G high mode:

• Hover all orientation.
• Forward flight in figure 8.

And without competence, the following:

• Pirouetting circles but only in the 'forward' direction.
• Backwards flight occassionally and usually ended with the heli in an awkward orientation. 

Stall turns are shallow, I think it must be the 6G auto-stabilisation. The 6G is also the reason why it was hard to get the heli inverted and while inverted that I am able to fly easily.

This model has 6G (low and high), 3D (low and high) and 3D+idle up (low and high).
6G is very stable, the throw range is set up for upright flying, i.e. more up pitch then down pitch. In In 6G mode, if the heli is inverted, pushing the throttle and collective pitch upwards still increases the throttle and collective pitch.
3D has the same throw range as 6G but it seems not to be auto-stabilising. In 3D mode, if the heli is inverted, pushing the throttle and collective pitch upwards will decrease the throttle and collective pitch.
3D+Idle up has totally different throw range. I suppose it is also without auto-stabilisation. It behaves the same way as 3D mode when inverted.

Should I practise in 3D low mode for hover in all orientation and forward flight in figure 8? On the occassions I did, even at low mode, I found the heli unstable and rather difficult to control and changed back to 6G mode.

26 October 2015

Some parts arrived, but the packet of 10 rubber grommets came with only one. I have written to Banggood. (27 October 2015: Banggood responded and asked to send photo. I think this is their normal procedure even though it can't really prove anything. So I sent them this photo and Banggood has offered to re-send the parts to me. That's nice.)

The rubber grommet is quite difficult to install on the canopy shell. I tried many times. Most of the time it would either stay on the same side and fall off, some times the whole grommet would pass through the hole, and fall off. Occassionally, I get lucky and it get installed correctly. I have tried using the shank of a screw driver and found my fingers have better control. Maybe I should try to use a pair of tweezers, and I might, if I find my pair of tweezers.

I need to replace this servo on my 2nd V977. I have checked the receiver board with another servo to make sure it is this servo which, for some reason, is damaged. The servo plug is on the right side in this picture.

I have a spare servo among the spare parts but I am not looking towards doing it because I don't know how the servo keeper fits to the frame. I think I might have to either use a magnifying glass or my camera phone to see the details.

Rather then waiting until I replace the servo, I swapped the entire head assembly to my 1st V977. I removed the assembly by de-linking the two socket links and removing the retaining screw. The head, including feathering spindle and main blades was then attached to my 1st V977. A few flights confirmed the success of this transplant. I noticed that my 1st V977 flies easier, is able to climb faster and the motor and battery are less warm after each flight then my 2nd V977. This may be because it has a better setup then the 2nd V977.

20 October 2015

On Saturday, I flew the repaired V977 and on the 2nd battery, the blades flew out.

Contrary to what I had thought, it is necessary to ensure that the screws to the feathering spindle be fastened because the centrifugal forces exerted on the blades are great. I am just glad that nobody is hurt. Chris suggested to use loctite. A few parts are missing, a rubber grommet, a ballbearing, maybe some concial spacers etc. I shall wait for the ordered parts to arrive from Banggood to repair the V977 and meanwhile I shall fly the new bnf V977.

On Sunday, I was with Thang and he thinks that the main gear and pinion are too tightly meshed. When I returned home, I made some adjustment to the motor mounting and at one stage, I even noticed that although they look alright, the pinion would spin but not drive the main gear. Some more hit and miss adjustments and at least I got it working again.

On Monday I had a few flights and then noticed that not only were the battery and heli warmer after each flight then the older V977, it seems to be getting hotter with each flight. It doesn't seem to fly as well as the old one as it ballooned more when turned windwards. On the sixth or eighth flight, it got so bad that the motor stuttered and would not spin the rotor. I disassembled the main rotor and found the top ball bearing was binded to the main shaft. The ballbearing could not be turned. Further disassembly involved releasing the nylon collet and supporting the ballbearing with a vise to tap out the main shaft. The main shaft was corroded, I couldn't wipe it away with WD40. I changed the main shaft and the nylon collet (it looked grinded), squirted WD40 and threaded the bearing and found it working again. The shaft was then assembled with the rotor head and slipped through the main frame to the lower bearing and main gear. I did some hovering test at home and it worked fine. The rotor can now be turned by hand easily.

I don't have any spare main ball bearings, I think I should order them.
The screws to the feathering spindle must be tightened/loctite, or, use new feathering spindle to ensure the threads are not damaged previously.

14 October 2015

I changed the feathering spindle, the 2 rubber grommets and inspected/ rectified the blade holder.




The difference between the two sides of a ball bearing set.


This is how the bearing should look like when placed in its holder.


This is how I made used of the feathering spindle to insert the ball bearing sets into the blade holder/clip.














The two rubber grommets at the top of the picture are the ones removed from the rotor head.
I replaced them with the lower pair beside the conical spacer. The upper pair has imprint of the conical spacers, perhaps they are still re-usable so I am keeping them because apart from this visual clue, it looks and feels fine.

The photo on the right is what I believe to be the real reason behind sloppy blade holder/clip. They are the remants of a ball bearing set extricated from a blade holder/clip. One blade holder/clip has the bearings installed correctly while the other has one bearing installed the other way round which I suppose, cause it to break out, causing accelerated wear also to the other bearing. I replaced what looks like a pair of good ball bearings, but when the holder was rotated on the spindle, there were notches in the movement and the other holder felt smooth. Anyway, I think it is still usable and I shall use it. When my ordered parts arrived, I shall do a new rotor assembly as a standby replacement.

Slop to rotor head/blade holders

1. Slop is not due to untightened spindle screws.
2. Nor was it due to damaged rubber grommets in this case.
3. Slop was due to damaged ball bearings.

I wouldn't be able to inspect the bearings were it not for my camera phone. I shall fly the repaired V977 and keep the bnf in its box.

13 October 2015

I replaced the undercarriage, then I noticed one blade holder was loose. They call it clip, which led me wondering if I was to expect some clips with my holders. I thought that the holders became sloppy because the screws were not screwed into the spindle tight enough, so with 2 screw-drivers, I tightened them as much as I could. Then I realised that the screw is only slightly bigger than the bearings, and the whole spindle can be pulled through the blade holder's ball bearings by hand and has probably removed the inner part of a ball bearing in the process.

There must be a direction to install the blade holders' ball bearings. One side of a ball bearing has the small bearings visible. I think this side should be placed facing each other in each blade holder. The screws should be on the side where you can't see the small bearings. I think that's how the bearing was assembled and mounting it the other way will be disassembly of ball bearing. Also, it makes sense when the visible bearings are held captive by the bases of the blade holder.

The second thing I realised is that I shouldn't tighten the screws too much because they could not be meant to reduce slop in the blade holders. They only need to be screwed in to offer some minute resistance to what I think is practically non-existing pulling force, if any.

So I guess the process of assembly a rotor head should be:

1. Insert a pair of ball bearings to each blade holders. The side of the bearings showing the small bearings should be placed facing each other so they will be seated against the bases of the holder.
2. If any blade holder is loose, replace the rubber grommets on the head piece. I think my rubber grommet was deformed from constant compression. I should trust the factory to have machined exact length for the spindle and not resorted to screwing in harder.
3. Lightly screw in the screw to one end of the spindle, and slide it through one assembled blade holder.
4. Slide the conical washer onto the spindle against the holder. The base (bigger side) should be towards the head.
5. Push the rubber grommets into the recesses on the head and slide the spindle through them. Fit the other conical washer before sliding in the other blade holder/clip.
6. Then lightly screw in the screw to secure the spindle in place.

If this still doesn't work, I am out of ideas.

I have just placed an order to Banggood. When the parts arrive, I shall assemble a new rotor head following the 6 steps above. I think it should work.

And since my bnf has arrived last Thursday (8 October 2015, about a month from order), I shall fly it and reserve the assembled new rotor head and the older heli for spares.
Enjoy the good things now and stop hoarding.
And I shall not bring my MI 10000 MAh charger anymore since I have now 10 batteries of 520MAh and 1 of the original. 10 flights of 5 minutes is 50 minutes flying time and almost 2 hours!

Binding of bnf was done after referring to the manual. To recap:

1. Power on the heli, let it blink rapidly.
2. Power on the trans, wait and the heli blinking light will turn steady.

So it seems that the heli is bounded to the trans and not the other way around.
To ensure that the heli will not bind to other trans:

1. Power on the trans.
2. Power on the heli, and it will bind to the trans.
3. And when flight is finished, to unplug the heli and then the switch off the trans.

5 October 2015

By now I can zoom the V977 comfortably with high rate on 6G. I find that I like to use a lot of rudder. I would zoom forward, bank, pirouette, bank and fly it back in a figure of 8.

I can also hover nose-in but tail-first flying is uncomfortable. On Saturday, I did one tail-first round.
On 3D setting, the V977 is too responsive to be comfortable, even at low rate.

When I practise, I took all my 6 batteries, and the charger powered by my MI 10000 MAh battery which I bought primarily for this purpose. I timed myself to fly 5 minutes and land, reset timer to 5 minutes, removed the battery, off transmitter, and connect used battery to charger. When 5 minutes is up, I fly the V977 for another 5 minutes with another battery and the cycle repeats until I have used all 6 batteries. By this time, 1 or 2 batteries would be charged. For each flying session I can fly 12 times, by then I am less focussed and I stopped. My MI 10000 MAh battery is then around 1/4.

I ordered a bnf V977 combo (with 5 pieces of 520 MAh batteries) on 8 September 2015. It has not arrived. The order status advised is it was shipped on 13 September 2015 by 'Air Parcel Register' from China warehouse (via Sweden), but it was not trackable. I think it should arrive this week.

7 September 2015

Un-controlled Spinning to the right

While in hovering flight the heli spins to the right. Tail rotor was spinning very fast and no control from the rudder stick.
Checked internet and did what others did and solved the mystery. Rudder's white signal wire came loose. Need to solder.

Did the soldering and it now works.

Physical conditions

Now replaced:
1) main gear

31 Aug 2015

Physical conditions

Now replaced:
1) main gear (and it seems that the second one is going to fail soon even though I only installed it for a day)
2) main blades. With a few crashes the new blades are also nicked and scratched.
3) tail rotor blades. Looks good.
4) 1 blade holder and 1 bearing. It was difficult to install the bearing to the inside of the blade holder.

The battery holder keeps popping out.
1 forward canopy holding pin was broken.
I taped the tail rotor motor's wire to the pitch servo with blenderm tape because one of the wire prefers to rest on the hooked pushrod.

Flying

6G and high rate is preferred. 3D is too touchy, it reacts too quickly but I do like the greater deflections. I turned on 3D only when it is already hovering. Having 3D turned on usually results in crash. I am keeping idle-up out for now because I have had a few crashes with the main motor spinning at high speed before I could switch throttle hold.

I like the high headspeed because it is good for outside flights; it handles windy conditions very well and does not balloon like a fixed pitch.
I like the collective pitch because the heli reacts immediately to my input.

Repeated 5 mins of flying 5 mins followed by 5 mins of cooling off and charging the used batteries charging  at the same time means that my 6 batteries are used up in an hour and by then, the 1st used battery is charged and when all 6 batteries are used twice, I have flown a 2 hours session.