An Upper Rotor Fix for the Robocopter GST T-Series
By Lymond
The Helicopter
My girlfriend recently bought me an Extreme Flier Robocopter GST T-Series R/C mini helicopter in a groupon deal. It's amazing fun, essentially a very small radio controlled helicopter that you fly inside your house. It's rechargeable from a computer, very agile and controllable (once you get the hang of it and don't panic) and has what appears to be a reasonable construction. It's body is a metal shell, and most of the parts screw together, all in all, very repairable. Which is why it's strange that a) the upper rotor assembly hangs off two plastic pins less than a millimetre wide and b) the spares seem very hard to come by.
When mine broke, the initial symptom was that the helicopter started swinging round in circles. Then the upper rotors hit the lower ones and it fell out of the sky. There are two items that control the upper rotor assembly, the plastic cross pin that holds the rotor hub onto the metal shaft and the two loop-clips that connect the balance bar to the rotor hub. The loop-clips just pop off however, the cross pin had actually snapped. Super glue didn't work.
My Quick Fix for the Rotor Assembly
You'll need a pin of some description, I used a sewing pin (needles are too brittle), a pair of pliers, preferably long-nose with a reasonable cutting section, a fine needle or second pin (finer than the sewing pin), a small cross point screwdriver, some small pieces of rubber or plastic (I used some insulation off an old pair of headphones), a gas flame (on the stove top) or soldering iron and a steady hand. PLEASE NOTE, sharp hot objects will be used, don't stick yourself, burn yourself or otherwise injure you or anybody else. Try to make sure an adult is at least supervising the repair work...
1. Disassemble the upper rotor assembly.by first loosening the two screws just under the balance bar. Take the whole assembly off the main metal shaft.
2. Take the rotor hub off the plastic shaft section (if it hasn't already fallen off).
3. Take apart the hub by undoing the two screws at opposite corners of the square (not the ones that hold the actual blades onto the hub).
4. Take the plastic rod with the balance bar attached to it, look for the cross pin. On an unbroken assembly, the cross pin sticks out another one or two millimetres on either side and these fit into the holes on the inside of the square rotor hub. When these pins break, the hub is no longer attached to the shaft, apart from at the loop-clips.
5. Using the pliers, cut the point and the head off the sewing pin to leave about 6mm of the pin shaft. Cut the plastic or rubber so it is about 1-2mm long and will fit both over the shaft of the pin and into the holes on the inside of the rotor hub.
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6. This is the very delicate part, Heat the needle in the gas flame, (holding it with the pliers) and while it is hot, carefully poke a hole through the remains of the cross pin, as level and as cleanly as possible. (If you have a dremel tool and some skill you may be able to use a very fine (1/4mm ish) bit to drill the hole instead). As the pin is hot, it should go through quite easily. To pull it out, gently twist the pin with the pliers until it frees and you can pull it out.
7. Poke the 6mm pin shaft through the hole. You will not be able to use it like this as the main shaft has to go up through the plastic bar all the way to the balance bar at the top where it is held on by the two screws just under the balance bar. You will however, be able to see whether the pin actually fits.
8. Fit the balance bar back onto the helicopter and tighten the two small screws that hold it in place. The main rotor shaft now runs up the middle, across the hole you have just made.
9. Cut the 6mm pin shaft into two equal parts with the pliers. Try to make sure they are equal. Check they fit into the holes in the cross pin and don't stick out too far (otherwise the rotor hub will not fit back on).
Spares and Repairs for Other Makes
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10. Carefully heat the small pins and quickly set them in the cross pin. The heat will slightly melt the plastic, helping to keep them firmly seated. Alternatively super glue could be used, though be careful you get the pins seated correctly before the glue sets.
11. Put the small pieces of rubber or plastic over the pins to firmly hold the rotor hub onto the pins.
12. Re-assemble the rotor hub and make sure all screws are tight (careful not to strip the plastic by over-tightening the screws). Clip up the loop-clips and you're ready to get flying again!
I've flown my copter for about an hour (~10 flights) with this fix and so far its holding and she flies steady. I am going to get a replacement if its available but am anticipating this might take some time. Meanwhile I hope this keeps you flying too! Please note, this is a temporary fix to keep me in the air until I can get a spare part ordered.
FOR THOSE WHO HAVE LOST THEIR COGS
Comments
Spares ahoy! Emailed the sales lot, got back to me, seems very easy and not expensive! Excellent
Great article. Will try your fix probably this afternoon - have the same problem after around 10 flies :). Thanks a lot for sharing!
Hi Arthur, thanks for the comment, hope it worked! I had a disastrous landing on the back of a wooden chair (trying to be fancy and land on a very small surface) broke two rotor blades, snapped my fixed pin arrangement and broke the plastic fix that holds the tail fin in place. Out of commission until the proper spares arrive, which are taking their sweet time...
Thanks great... its working perfect! thanks a lot!!
Hi Lymond, I got exactly the same problem on my Robocopter. Around the 5th flight the crosspin broke when it hits the door frame pretty hard when I tried to fly through it. Thank you for the post! I just e-mailed the sales lot as well, but I don't know how much the parts will cost me and how long it takes before it arrives... maybe it is also wise to order a bunch of spare parts because it seems to break easily.
Hi, it was very tiny and sensitive work but I managed to fixed it, as I put some liquid super fast gum on both tiny pieces of pins which made them more stronger as without gum pins are keep coming out. anyway thanks alot, you save my £££. I think that parts should be metal not plastic.
Thanks
Great article! I was wondering if you could post a link to a location to buy replacement parts. I can't seem to find them anywhere. Thanks!
Hi Greg,
You will need to email their customer services -
customerse?rvice2@extr?emefliers.c?o.uk
I sent them an email requesting parts, they sent me a parts list with costing. I replied telling them which parts and how many and they send me a paypal request.
Make sure you send the request from the email that is linked to your paypal. All they send you is an email form paypal request. Mine was sent to the wrong email (they didn't ask) and I'm still trying to get them to resend the payment request to the right email account.
Hey Lymond - thanks so much for the advice on this - outstandingly helpful!
I've just painstakingly gone through the steps described and the helicopter is flying again, albeit a bit drunkenly.. The new hinge joint seems a bit stiff so I suspect that's stopping the rotors from gyrating as smoothly as they should do.. As much as I hate to I guess I might have to take it apart again to try to loosen things up since from past experience I know there's little chance of hearing back from Extreme Flyers this side of the new year...
Thanks again for the excellent post!
- Oliver
Hi Oliver, thanks for the comment, yes sounds like its too tight in the holes in the rotor hub. The balance bar on the top has to be completely free to move up and down (and take the rotors with it) as this is the 'gyro' that makes the control easier and stops it flying in drunken circles. I ran mine into a chair and am currently surviving on a split pin fashioned out of a paperclip, melted into the plastic section of the upper rotors and glued in place. It was way too tight and I had to take a scalpel to the rotor hub to get it to work. I'm still waiting on spares too. Best of luck!
I have the same problem with the drunken flying and made the same assessment. The gyro and rotors really need to be able to move freely for the heli to fly properly. Also, its been painstakingly difficult to get ANY response from the company. Ugh.
Didn't start trying to fix mine yet as I am awaiting reply from extreme fliers. It seems the customer service isn't very responsive... Maybe I will try give it a try and see what happens to my chopter.
Yes, the customer service is overwhelmed and underwhelming. I got a response reasonably fast but since they sent me a link I couldn't use, its been quite bad!
This is a different problem but I'm hoping someone could give me insight into my issue..
When I crank up the throttle, it seems like it isn't getting the lift it needs to get off the ground. It looks like the blades are hitting their full spinning potential about a third or halfway up the throttle stick. Copter is fully charged. There wasn't any significant crash when this started to happen. It died, I charged it, then this started. Maybe something relating to the motor?
:) yeah j, if you check the bottom of the rotor blades somewhere near the hub there should be numbers 1 and 2. It sounds like you've got the wrong rotors on either the top or bottom. You need to work which way they're spinning (contra-rotating top and bottom blades) then work out which way the blades should spin and apply accordingly. Make sure you have one set of number 1 blades and one set of number 2 blades in the right order.
Well, the blades are all on correctly. The copter worked, I turned it off, charged, turned it back on and suddenly no lift.
Thank you very much for the speedy response btw :)
I had mine working 20 mins till I had this problem. It's ridiculous how its made of plastic and how they don't give u a spare! Customer services will be busy after Xmas this year .....
Same problem..... does someone know the part number, to make ordering quicker?
All, this is what I got sent by email. Bear in mind prices may have changed!
1x upper blades set: £1 .99/ unit (assembled
with the balance bar, link rod and upper blades)
1 x blade : £0 .99/ pair
1 x link rod: £0 .49/ pair
1 x landing leg: £0 .99 /set
1 x tail rotor: £0 .49/pc
1 x USB: £1 .99/ pc
Postage: £1 .50 (with jiffy bag)
You only have to send an email with your
order and the DELIVERY ADDRESS.
We will send you a money request and upon
reception will ship the order.
I emailed: customerservice2@extremefliers.co.uk
no part numbers but hope that helps!
So what is the part needed to fix? Do I need to a buy new blade assembly? I just broke the upper rotor hub. I want to order about 10 of them! I see this part as the main weakness of the product blades seem good quality.
I paid $30 for mine. I think I'll just buy a new one instead of paying the same amount for spare parts
so far as I am aware, not having received my spares yet, 1x upper blades set: £1 .99/ unit (assembled with the balance bar, link rod and upper blades) is required to replace the broken cross pin of the upper rotor blade hub. Also at £1.99 and £1.50 postage (£3.49 or about $5.50) spares are worth it compared to $30 for a new one, albeit annoying that such a poor piece has been included in construction.
hi,
I have a different problem. My chopter fell out and hit the ground this morning. Since then, the lower (main) blade is not rotating at all which means that my chopter is not lifting at all. The upper 2 fans are working fine. On close examination inside the body of the chopter the upper of the white wheel is not rotating. Should this be linked to anything? PLEASE HELP!!!!!
Hi to all.
Great fix for top Done it this afternoon with pins and wire great fix better than real way stronger.. Have another problem Choper saying chargered on light but when i try to link up remote flashing then stays red and choper doesnt fly... Great choper but some little problems i think Any 1 Have any fixes
Hi happyherbal, try making sure the helicopter is definitely switched off before you put it on charge, mine has a bit of a dodgy on/off switch.
thanks for your 1st post, found very helpful, only difference I made was to use a small nail 0.063" dia, which is ths dia. of the hole in the rotor part, drilled into the plastic part just enough to enable the 0.063" pin to drive on it. lovely piece of kit to fly and operate.
Lymond Cheers just sorted it... It was the switch... Great we choper thou... Hope we can get the parts of these boys i have them emailed... Anyone get the parts yet...
Lymond,
Thanks a lot for your tip! The same problem happened to me 1 day of using. I was able to repair it...and save the Xmas from my 10y old boy. This is really poor engineering to have this plastic tips. Shame to extremefliers...but thanks to the internet community..
all,
please can someone help me with my problem. the upper assembly is fine. its the lower one which is problematic. My chopter fell out and hit the ground this morning. Since then, the lower (main) blade is not rotating at all which means that my choper is not lifting at all. The upper 2 fans are working fine. On close examination inside the body of the chopter the upper of the white wheel is not rotating. Should this be linked to the lower wheel?
sreeramralls,
I'm having the same issue but in reverse. On closer inspection it seems there may be a part missing on mine. On yours either side of the 2 white plastic rotating wheels do you have 2 small white cog like pieces? I only have 1 see which is why i believe only the lower fans on mine are working.
no. only the lower white one is linked to a cog. the upper one is like free wheel. i think the top blades shaft rotates the lower one as well. however in my
case only the upper blades are rotating. it was fine untill yesterday morning.
hi bmwkings, ive examined it again and i can confirm only the lower white plastic wheel is linked to another white cog towards the tail section. there seems to be a provision for another cog on the opposite side, however i cant see any cog there. i guess it must have fallen out when my choper hit the ground. maybe someone else can check and tell us if cog is required on both sides.
Hey, got a slightly different problem, my helicopter doesnt fly more than a few feet of the ground then after a minute or so refuses to fly at all then just doesnt respond. At first i thought the battery was low and charged it, and after charging it does the same thing. Only seems to work for a minute at a time... Does anybody know what the problem is? the copter is new and i only flew it about 5 or 6 times before that happened.
Hi Newman, I had a similar problem, and if your is anything like mine was, make sure the off switch is fully and definitely off before charging.
Im pretty sure its been off while charging. now it just doesnt respond at all but the light still flashes, on the remote and helicopter too.
Appologies for the previous comment.
I find that its better to turn the helicopter on, plug it in to charge, the light will be red, then turn it off while plugged in. The light on the USB will then go off, and it will begin to charge.
Also, make sure the channel is on A if you only have one helicopter in use.
Mine has broke like the one in the artical. Made a temporary fix with a new metal bar in each side. It works ok, but i feel it doesnt have the same smooth movement like before, and my helicopter now spirals slightly when hovering. Before it broke, it used to hover without moving atall!
Think i will get ordering a couple new top sections!
Very surprised that they never gave a spare one of these!
Shame they don't give better instruction for fixing issues.. It seems like a very easy machine to work on but some pics of the gears and how they should be configured would be nice. My small gear fell off the front and I have no idea what the orientation is, does it turn the top or bottom gear?
Ross i tried you suggestion but it still doesnt work. The light on the front of the helicopter just keeps blinking. Any ideas?
yes it should have cog on cog on each wheel ,ie,one big white cog and a little cog on the motor of each wheel,4 cogs in total,trying too get the small motor cogs but dont see it on the parts list??
Hi Same problem as J4 not enough lift . Small cog on lower gear had fallen off and was refitted . Now no lift even though all rotors are turning at a high speed. Heli nearly lifts off but just not enough power.
Any ideas????
Just checking back in to say that once Lymond's upper rotor fix had a chance to loosen up it worked like a dream and the helicopter got back to flying almost as new - so thanks again for that :)
My main problem now is that I've gone through all the rotor blades and am finding those impossible to fix even with a careful combination of glue and sellotape!
As for Extreme Flyers customer services, I don't hold out much hope on parts since I'm still waiting on a second helicopter which was ordered a month ago.. Next time round I'd suggest going to these guys on eBay for only a few pounds more - will contact them to see if they also do spares...
Thanks Lee. Is it possible to take a picture of ur Heli and post it here? Need to check all the cogs. alt can you send it to me on sreeram.ralls@gmail.com
Thanx
yer had the same problem with the pivot pin's breaking,did the fix like you said copter is flying great,had a few crash landing and still fine,im waiting for a reply from there spare's department and stated the problem with them pivot pin's.
Brilliant! Xmas was saved by these great tips!
brilliant! put a needle in as pin and worked a treat, did have to use the shaft to file away the plastic on the inside of the hole as it was catching at first..thx for the fix.
I do not have a clue why my sons helicopter just flies off at all angles - everything looks fine to me. Does any one know if there is a shop you can take it to , to be fixed. I live in Birmingham UK
Hi Julie, I don't know of any shops but there are one or two things you can have a look at.
1. up the throttle just enough to get the heli moving. Don't take off and preferably in a large free space.
2. Identify movement, e.g. forwards/backwards, left/right, rotation clockwise/anticlockwise or yawing (swinging motion often round in a circular fashion when the heli is in the air, tends to get more pronounced the longer it goes on).
3. use the trim functions (clicky little buttons at the bottom of the left/right stick and the side of the throttle stick) to try to counter the movement you observe when running the throttle up slightly. Counter forwards or backwards movement with the trim buttons next to the throttle and rotational movement with the trim buttons next to the left/right stick.
4. Yaw is very difficult to counter and tends to indicate there is something wrong with the heli physically, rather than being badly trimmed.
5.Check both loop clips are on. These attach the top blades to the balance bar at the top and can be observed on the third picture down in the article.
6.Take the loop clips off carefully, if the upper rotor blades and rotor hub either drop to the bottom rotors or sag, you may have broken the rotor hub pin, about which the article is written. If this is the case, buy another upper rotor assembly or try following the instructions above.
7.Once you have clipped the loop clips back on, check the upper rotor/balance bar assembly moves freely. Tilt the balance bar with your finger, it should right itself to roughly horizontal without sticking.
8. Check the tail assembly with the small motor, the fins and how tight all the fittings are. Hard knocks may loosen some of the fittings. If this is so, take a very small cross point screwdriver (jewellers or electronics screwdrivers) and gently tighten the screws.
9. Make sure the main rotors (both sets) swing freely. if the screw that attaches them on is too tight, the rotor has difficultly finding equilibrium. If you knock them with your finger they should freely swing to the end of the rotor stops.
10. Make sure you have the correct rotor sets on. The top rotor blades should both say A1 on the under side and the bottom pair should say A2. (Assuming it is an Extremefliers Robocopter GST model).
11. Very carefully and firmly hold down the heli by the landing skids and keeping your hands free (it hurts quite a bit if you catch the rotors across the knuckles) open the throttle. You should be able to detect whether the heli is pulling in a certain direction or the whole unit is vibrating. This may indicate something is broken on the helicopter.
Thank you for your comments- brilliant. Think you need to be on commission!
lee, sreeramralls, Joex7,
My guess (and it is a guess) is that if you have the throttle wide open and its not lifting off (assuming no damage to the battery or motors)is that the cog is slipping, either the big cogs on the main rotor shaft or the little cogs on the motors.
Also I have included some close up photos of my cog assembly as best I can.
Many Thanks Lymond,the first photo is enough for me to conclude that the cog on the upper wheel has fallen off from my heli. The lower wheel still has the cog. Wonder where I can source the cog for the upper wheel?
Lymond Everything on here great help... Choper was flying weird for a few days.. But it was the way i put it back together again wasnt right... But all good now great we job... Have it flying about the house... Thinking of getting a bigger 1 now...Many thanks stephen
My upper rotor pins came off after a few days of flying. What I have done is cut off the whole bottom section where the pins originally were. Then I soldered straight onto the metal shaft and just soldered on a big lump of solder. Using a small file I have filed down the lump of solder to form two metal arms. You can use the link arms to see roughly where abouts the solder should go. I just marked the position with a marker pen. This forms a really nice solution and best of all it's metal. After reasslbling the helicopter flew perfectly.
Hi paul, that its a very good solution especially since I have now broken mine to the point of not being able to use the plastic section! I have one query, isn't the solder a bit soft? Though I grant you, probably stronger than the original plastic arms!
Solder is solf but it sets pretty hard after heating. It's soft as in easy to file into the shape of the pins but I think it will be strong enough for this purpose. Mines had a few crashes and it seems to be standing up to the job. I will take a photo of what I've done and post it on my website, maybe today or first thing tomorrow as I have to go out in about an hour. I'll post a link when it's done. I also posted about the modification on the Extreme Fliers facebook page but they deleted the post soon after, lol.
Just posted a photo on my website of the modifications I made, see link below. Make sure to use enough solder and be sure to leave some solder around the whole drive shaft as this will make the joints stronger. There's enough room inside the upper housing to get away with leaving a fair bit of solder in there around the drive shaft without it touching anything. Looking at mine I could have left a lot more on as I've filed it down a fair bit. Something else maybe to look into is different solder types as there maybe some that are stronger than others. I just used regular solder for mine.
That is an awesome fix! Thanks for posting
Thanks for the tip about putting a rubber sleeve on the pins on the top rotor. I did a repair with just a pair of steel pins in the hole I drilled in the plastic and after one or two crashes the pins have vanished, presumably fallen out. I also had a problem with the charger socket being pulled right off the printed circuit board, due to the 'copter falling off the desk during charging, and having to be re-soldered.
I am surprised that no blades have been broken in spite of many crashes due to flying it in a congested living room & trying to land on small tables etc etc.
Thanks for your help Lymond, it has given us something to work on
Hi Julie, thanks for commenting. If you have access to a soldering iron, check out Paul Corfield's fix!
I got mine for Christmas and had the same problem as above. Used a thin nail and superglue left overnight to set to repair. Was a delicate operation but it worked a charm. Its no longer wobbling round like a drunk thing!
My new problem is the screws which attach the upper rotor assembly to the shaft. They won't tighten enough and the rotor is slipping on the shaft. Its now bad enough that I need full throttle to take off with a full charge. I don't have a soldering iron.
I wish they'd made this part out of metal, they made so much else from metal.
Hi Alex, I now have the same problem with the screws and judging by some of the comments, other people must have the same issue whether they realise it or not. I was very careful but somehow have stripped the plastic threads. I'm going to experiment with superglue to try to create a new screwthread that will hold the screws properly and allow the whole plastic bit to clamp firmly to the metal shaft. I'll let you know how it goes!
One of my threads was stripped from the start and the helipcopter was assembled like that as I saw it was loose from day one. Luckily the other one is working fine. Might be able to put a bit of tape round the drive shaft so that the plastic assembly is a snug push fit. That may prevent it from spinning for those that have stripped threads. I can never understand why plastic is used instead of metal in such a key componenet. Makes you wonder if they do it so they can continue making money throughout the year from selling the spare parts. I guess the sales of the actual helicopter are going to be very seasonal, like the bulk being sold at Christmas. That upper rotor assembly would be such a simple redesign for them and if they don't go ahead an do it then it says a lot about the company and what they think of their customers. Even if they still want to use plastic it would be a simple redesign to make it way stronger. We can but hope. My son has a simple UFO copter that only goes up and down and even the rotor assemblies on that are much better designs than the Extreme Fliers ones.
My soldered pins are still working fine after some quite bad crashes.
My soldered pins finally broke today but I did push the copter into some quite bad crashes. I also wanted to try a new way to model the solder in a much stronger way. With the first attempt at the soldered pins I filed too much of the solder away so this time around I've come up with a much stronger conical design.
See this detailed step by step to see how I did the new design. This is way stronger and I can't see this one ever breaking.
Woop! A good amount towards my faith in these guys being renewed: spare parts available online www.extremefliers.co.uk/shop/parts-and-accessories. Lots of stuff including small cogs, spare upper rotors including the infamous pin and a snazzy red metal shell!
In the spares they list a replacement helicopter for £15 which is £30 cheaper than buying the helicopter new. No replacement transmitter listed but once they bring out the Hyperbrain dongle for your smart phone then you could potentially save a lot of money compared to the new helicopter price.
Hi Guys,
I have just got a GST Special Edition, which is great! However, I only seem to get 5 minutes of flight time before it needs to be recharged!
Is this normal?
Cheers
Hi Lobster1001, That's maybe a little on the low side but not by much. Depends on how hard you're hitting the throttle.
Hi Lymond,
Thanks for the reply :-)
Cheers
HI
I was hoping you just sell the rotors
Hi Hoori, I dont sell anything :)
Speaking of sales - has anybody had any luck getting spare parts through from Extreme Flyers yet? What a bizarre attitude to customer services.. thankfully they only sell toys and we're not dependant on them for body parts!
They took my money last week. I trust they will be sending the two spare top rotor assemblies and the undercarriage I ordered. Watch this space.
I had an automated response from extreme flyers but nothing else and its nearly 2 weeks. How long do people normally wait for a reply.I cant believe how bad they are, and it is such a great little helicopter.
We got an automated reply and response within 48 hrs. Followed by a phone call to me to discuss the fault. A new rotor assembly is on its way to me. Perhaps their customer service is getting to grips with the post Xmas backlog?
I finally got a reply from the customer service, giving me a link to where I can order parts on their website. The full upper rotor is €2,50 so it is reasonable. But before that I tried to fix my broken crosspin with this guide, every went well except one thing: "careful not to strip the plastic by over-tightening the screws"... this is what I accidently did, now the pins are fixed but the upper rotor couldnt be fixed on the rotating shaft anymore, making the fix useless -.- I find no way to refix the upper rotor blades anymore, so leave me no option to wait for the spare parts. There is a €18,- full replacement, excluding the controls and usb chargers, I think that is also fair enough in case the chopter is total lost.
Hi Fung,
I eventually did the same (too many crashes) and briefly fixed this by shaving some plastic dust of another area of the plastic rotor section and melting them into the screw threads using a hot pin. I then manually retapped the hole using the screws and its now fine!
Www.extremefliers.co.uk/shop/parts-and-accessories
Hi Rileyuk, thanks, I already ordered mine a while back, still waitin' on delivery though....
My parts arrived Jan 18th. All OK back in the air.
Great to gather that someone's parts have arrived at least - I'm still waiting on them for a spare copter ordered in early December so hadn't yet dared to place a further order for parts!
Yeah, I just hit the ordered two weeks ago mark, though have been trying to order new parts since mid November :)
One of the company spokespeople said on facebook that they've only had a few hundred orders for spares out of 65000 helicopters sold. Makes you wonder what's taking the time for only a few hundred orders...
Super thread. Crashed on Christmas day. (Into a Bratz hair styling kit. Lost one link rod. Untangled all the hair. Fitted spare link rod (Supplied) and tried to take off. Circling violently. Pops link rod. Suspect that Upper rotor assembly is damaged. Replacement arrived today. Still circling (in ever widening circles). Hav tried trimming on the ground . Behaves reasonably on the ground - but, as soon as you lift off - you are in trouble!
Is it just the trim?
Hi Guys,
From day 1 my copter wont fly forward. It is very good at everything else and flies neatlty backwards, left and right. I know the rear rotor spins when reversing, but mine does not spin at all going forward. Is it supposed to? I assume it needs the tail to lift slightly to create pitch to move forward.I emailed Extreme Fliers 3 times now since xmas, they are ignoring me.
Cheers.
MrBassman, I don't think the yaw type behaviour (round in circles and swinging like a pendulum) you're describing is purely trim, sounds like there's something else wrong. Maybe check the balance bar at the top moves freely and has nothing wrong with it (this is the 'gyro' that stabilises flight on the copter). Second check the main axle running the rotor blades isn't bent. Even a slight bend will cause the behaviour you're describing. Other than those two I can't think of anything else.
Hi Vinnie, the copter moves forward when the rear upward facing tail rotor pulls the tail upward, tilting the nose down and allowing the main rotors to cut the air at an angle, pulling the copter through the air. If it doesn't rotate in one direction...no movement forwards. If it hasn't worked from day one, perhaps you should contact them for a replacement or refund?
Hi Lymond (Sorry for double posting - accident). I think you could be onto something with the Main Shaft. It doesn't look bent - but, judder comes into it as it slow down. Balance bar moving freely (As you would hope from a new Top Rotor Set)
Is the main shaft easilt replaced?
M
I have tried twice to order spares but the 'method of payment' page seems not to exist. The system appeared to take my order and indicated that I had paid by paypal, except I don't have a paypal account! You don't seem to be able to get to a credit card payment page. Has anybody else had the same problem?
Hi Griselda, I think you can only pay via paypal, as far as I could see they don't offer any other payment method.
Hi - so glad I found this forum. Similar problem to others with non-rotating bottom rotors but I have got the little cog. How do I get into the body of the chopper to fit it back on again? Can't work out the instructions in the faq on their website. Thanks for any help you can pass my way. Photos of assembly would also be gratefully received!
Will the Syma S107G main shaft fit on the Robocopter? Any comments?
Hi Vik, I have no idea, but I would suspect not. The main shaft is actually quite complex to allow the contrarotating top and bottom blades. My only direct experience with this is trying to use syma rotors, it didn't work despite the rotors being the same size.
great info lymond.
wouldn't have even attempted a fix without your repair guide. sewing needle cut down to size was easier to do than i first thought. i used some wire strippers to remove the plastic sheath from some old auto wire to fit the new pin. then just trim to size using a craft knife. works brilliantly!
have ordered new parts in the meantime from extreme fliers but 2 weeks waiting and still no sign of them.
heli is still flying great though.
I guess there is no other forum in the entire internet that has suggested this fix. the plastic hub is definitely the weak spot of many coaxial heli models. thanks for the awesome tip. Had been searching the internet for this for over a year now.
By the way, my heli also crashed when I was trying to land it on a wooden chair
Damian, Harisankar, thanks for your comments, check out the comment by Paul Corfield with a link to an even stronger fix if you have a soldering iron!
Harisankar, you can buy replacements for the upper rotors now, howver they do seem to take a while to arrive!!
I have a Robocopter gst special edition.
The helicopter flew perfectly stable. Now it flies unstable. Suddenly, the helicopter makes rocking motions while I don't steer. Just hanging in the sky?! The fly is unreliable.
None of the parts are broken. What could be the cause?
Hi Reiziger, this seems to be quite a common problem developing with the Robocopter. I now have a second 'chopper only' because the first one developed that very problem. The only thing I can suggest as the cause is a bent main rotor shaft. When I get time I'm going to take it to bits and confirm. The fix is not so simple, straightening out the shaft. If its solid metal, it might be possible to roll it between a flat surface and a flat heavy object, otherwise, it's down to obtaining a new shaft.
Thanks Lymond! your fix technique has my GST back in the air while I wait for new upper rotor assemblies from England. Great post!
Lymond 6 months ago
as a note, still flying, however on breaking the second A2 rotor and not having any spares, I redrilled a very small hole at the bases of both broken rotors and now have a new set, a little unbalanced but it just adds to the fun!