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Twister CP 2 problems


Ajohnw
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any moons ago I could hover and move about an MFA sports helicopter that's still kicking around some where. Next I tried a small esky lama. Slightest puff of wind would send it anywhere but the biggest problem was take off. Very very reactive and nigh on impossible to control.
 
Thought I would try cp next so bought a used twister cp2 of ebay. Not had to play with adjustments much before so need a few ideas.
 
1st problem is that the tail rotor trim is at the end of it's travel. This controls it until I set enough lift to allow it to be skidded along the floor. The tail end then drifts out and then snaps back to the correct position. Seems the gyro works but the gain might be up the screw. Can the trim problem be corrected by reducing the static main rotor pitch?
 
2nd problem occurs at the point of lift off. Flips over rather rapidly immediately. Things look level and straight so I am at a bit of a loss. I haven't tried to trim that out but I suspect it would use up all of the trim travel or more.
 
Fortunately I tried it on carpet 1st which might explain the jerky gyro response.
 
 
Any help gratefully appreciated.
 
 
John
 
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I attempt to fly a Twister CP Gold.
Please note the attempt!
Due to the attempting, it makes me fairly good at the repairs which have been many.
 
Tail rotor trim first.
Reset the trim on the Tx.
Slightly loosen the servo mount on the tail boom and slide the servo down the boom until the tail rotor deflection is centralised.
 
Are you using the supplied Tx or your own one?
 
When you say it flips over, which direction does it flip?
Sounds like you need to check all the servos are adjusted correctly.
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Hi It's a cp v2 with a separate motor driving the tail rotor. Looks to be the same as the gold except for colour, even says TEST FLOWN on the box.
 
I'm using the TX that came with it.
 
Looking from the rear it flipped to the left.
 
 
All a bit terse as I'm cooking tea. The rotating oven in the stove is stuck.
 
John
 
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The tail rotor and gear etc looks fine. It also seems to have sped up a bit. Maybe the motor was a little sticky for some reason. Could be just lack of use but it still needs a lot of trim.
 
Looking at the swash plate neither the forwards/aft or the left/right movements are any where near equal with the trims central . Both bend the body in one direction. This I think explains the flip but I'm surprised how quick it was. One skid didn't even leave the floor and whack. There is a slight wobble in the head at low rotor speeds well below take off speeds. I'm not sure if that's normal. Or if it was there before the whack - think it was but not sure.
 
On the static pitch of the rotors I assume these helicopters mix in tail thrust against and speed while changing the pitch. So if the heli lifts too soon because the pitch is incorrect it wont set enough  tail thrust. This suggests that the whole mix will be out and the gyro is left to correct it. This is not good in my humble opinion.
 
It's all interesting because I don't think it's been used much. The guy who sold it couldn't fly it even with professional instruction. The video that comes with it states these are very suitable for beginners - jp's web site offers an entirely different opinion.
 
One point. Do you find that the elastic band that holds the battery in place is a joke. A really bad joke. Anyone know of a fix? It shows the same band in the video but doesn't show what the guy did before he actually flew it. No way will it fly with the battery simply slipped into the band. The c of g will go all over the place. Actually the battery would fall out.
 
To add to this I understand exactly the same helicopter is sold under various names even in different boxes.  I would be interested in names of compatibles for parts if I can't find the jp ones.
 
John

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Hi John
 
I had to set up my swash plate which was close to where it should have been but not quite there.
Having said that please bear in mind that I purchased mine without the Tx so I had to program my Tx and heli to match.
 
As to the flip, they do that at a frigtening speed, I suggest you fit training landing gear which at least gives you half a chance of stopping it roll over, and reduces the breakage rate - don't ask how I know.
 
If the main shaft wobble is only at slow rotor speeds then that is likely due to the blades not quite being in line due to them being moved fore / aft. Once the rotors are up to speed the wobble should disappear, if not you have a bent main shaft which is replaceable and can be obtained from your local JP supplier. Get a couple because you will probably bend another one.
 
Also check from a safe distance that both blades are running at the same height, view from one side - you should not be able to see 2 blades. If you can, stop the rotor, mark one of the ball joints (tipex) and adjust it. Test again and adjust until only one blade can be seen.
 
My CP Gold is advertised as for beginner to 3d, I am a heli beginner and I am struggling like anything. Certainly has cost me a bunch of parts.
 
As to the elastic band, I never used it. My lipo is fastened in position with velcro on the pack and frame and then has a velcro band around it to hold it secure.
 
I hope this helps a little.

Edited By Andy Gates on 17/07/2010 22:54:16

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Hi Andy I'm not exactly a beginner but not what you would call proficient either. As I pointed out I started with a 40 2 stroke MFA sport a long time ago. I could fly it around with a mishap from time to time. Thanks, your suggestions will help. The mfa basically worked.
 
On the cp2 I didn't intend to do anything other than skid it along to set up the trims -. as per included instructions. One skid was well on the ground when it flipped. It really isn't wise to try actually lifting a new helly without a training stand which I now have. Having been down this sort of route before I've visited a model shop. Came away with length of carbon tube. This will be fixed to the centre of the training stand and will pass through a hole in a landing pad a little larger than the cp2's stand. The pad will be on the end of something maybe a piece of ally tube about 4ft off the floor. The carbon tube will have something on the lower end to prevent it pulling through the hole. The hole will be sized to allow the carbon tube to angle something like +/- 30 degrees maybe a bit more in any direction. May sound daft but this will allow me to get a feel for the thing and practice hovering in one spot with little risk of any damage and to see what is going on. Actually no idea about now but people used to set up their transmitter mixing and trims this way. Cost from the model shop was £6 including a piece of lightish ply that I might need. Not ideal I know but this helped a lot with the mfa that had so much power that the carbon rod was a garden cane and the pad was a hole in the centre of a large steel garden table. The pad could be as big as you like really but I'm curious about rumours of ground effects on helli's but think it's mostly a lot of twaddle.
 
Model shops are terrible places. Helicopters the man says have you seen this and promptly flies a micro twister around the rather small shop followed by you have a try. I'm impressed. Micro Twister now sits along side CP2 Twister. Lift off is easy, forwards reverse too, left right rather sensitive as usual. The trim is fine if one's pushed. Ideal for practice or even learning. Full replacement rotor including blades about £8 but I managed to run the shop one into a metal stool and it survived - it uses IR so I had no control as it was behind the counter. Flying in the lounge and not sure what to do because it's going to hit something - easy - forwards or reverse it away. Many metal parts and rather well made. Good value too at about £35 even though they could probably be knocked out for 1/2 that. Sure of many hours of fun and lowish upkeep costs. Cheaper on ebay by a few quid but support your local model shop many of them need it at the moment. It's rather unusual for me to approve of something like this. In the case of the CP2 if it had flipped as it did and I had just bought it would go back along side a demand for my money back. Nothing should be that bad with centred trims.
 
 
Out of interest this small model shop has sold 35 micro twisters so it sound like I'm not the only one who is impressed. Flying a CP2 in the lounge would be a little dodgy to say the least. It's really for mild weather outdoor use and probably a handful too but I expect that. Interestingly left right could be less sensitive but then it would be tooooo easy.
 
On the training stands some manic importer and cleaver chinese designer who wants to increase the sales of spares is bringing in one that has legs that don't join at 90 degree so the width and length spread isn't equal. ideally they need to spread in all directions equally to something  over the diameter of the rotor. Even larger to start off with even covering the tail boom too. Oh well at least it was cheap and too big so that I can shorten it at some point.
 
The MFA's training stand was 2 crossed ally arrow shafts with one of those 75mm dia hard plastic balls with lots of holes in them on each end. Whole thing held on and together with cable ties. Just a thought for people with larger helli's. I bought the mfa of some one who could really fly it and he used the stand most of the time. Why waste money on spares, just remove the stand when you really need too.
 
 Hope there are no of my bizarre typo's in the above
 
John

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Hi John, speaking from memory here, about two years ago so bear with me on the answers, I believe that the tail rotor is controlled by a potentiometer on the 4in 1 and has to be adjusted so that your tx trim is at neutral ie it sounds like it needs speeding up, this may sort out your tail issues. As for the flipping over, disconnect your motor plugs from the 4in1 and raise the throttle, all the servos and the swash should rise nice and even. The slightest crash will cause damage and everything should be checked out after such an event, mainshafts can be straightened out in a cordless drill without to much hassle and the feathering shaft is always one to check. I believe that the esky honeybee cp is the same model and some parts are interchangeable. Not the easiest things to fly but if you google the esky or the twister there is a wealth of knowledge out there.......Glyn
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There are 3 video's that cover setting up a cp helicopter in this series including pitch, tracking and fly bar all by the same person.
 
http://www.youtube.com/watch?v=VArYrRQ4dxw
 
On blade balance things are a bit varied but one person removes the blades and holder and balances that on the rim of 2 glasses. Makes more sense than weighing each of them to me. In the early stages he also suggests setting the fly bar to 5 degrees pitch for hover practice and reducing it later to about 3 for actual flight.
 
The person in the previous post also describes a test stand but it looks a bit manic and ott to me. A board with a hole in it and a length of tubing does work. Add some sort of adjustable stop on the tube to limit lift and set the size of the board in relation to the size of the training stand if fitted so the that heli can't tip over. The hole size needs to be considered in relationship to that too and say 2ft or more lift. Fix the lot to a table with a woodworking clamp etc. This is probably more challenging that actual hovering at 4ft plus but with practice it should be possible to move in all directions and turn in any direction - if the helicopter is up to it. Maybe the video's will help with that.
 
One of the comments  in the first link I posted doesn't sound entirely correct to me. Left right turns in relation to the tail rotor thrust. At any point when it's stable it's running at a speed to counteract the main rotor, increasing speed or reducing it's speed to turn could have more or less equal in effects, depends on the slow down rate to speed up ratios and thrust changes.
 
John
 
 
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Well a gallon of welsh cawl is in the slow cooker and I've started checking it over. 30 sec and I notice one of the blades is the wrong way round !  Now why didn't I notice that when I skidded it along the floor.
 
John

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Hehe, that's not going to help at all! I assume that's a main blade rather than tail, right?
 
Most single rotor helis require right cyclic input on takeoff to counteract the gyroscopic effect from the tail rotor. I trust this isn't what you refer to when you talk about it flipping over to the left on takeoff?
 
I think a lot of parts are similar if not the same as the E-Sky Honey Bee CP2 and the E-Flight Blade CP. It looks like the bell-hiller mixer is a totally different configuration though, so I'm not sure how many parts are actually compatible. The HB CP2 and Blade CP suffer a lot from sticky collective which makes takeoff a little crazy. I don't know if the twister CP2 is similar in that respect or not.
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Yes it's the main blade and of course the end took a small chip and I suspect the engine shaft which in this case includes the gear has a very slight bend in it, Fortunately it really is very very slight.
 
Going from the videos the pitch is too high but that's assuming there should be near zero pitch when the 3d switch is used. I would say there is about 5 degrees at the moment. Any one any thoughts?
 
I've had the head off and the blades were 1 loop of tape light on the undamaged end. It spins up more smoothly now but does shake about at one rev setting.
 
On the pitch the it struggles a at full throttle again suggesting there is too much pitch according to the video's. Any thoughts the suggestion that it should reach max revs at full throttle and not struggle seems sensible to me.
 
One blade lifts slightly more than the other too but as the revs increase lower one more or less matches it but bends more. There's a difference at the lift of speed. The tips match at  a throttle level for the brave. Maybe we need to match them against bending loads too.
 
The head was difficult to get off and rather hard to get back on too. Reason the hole in the engine shaft for the retaining pin. Rough edge. I fired up the engine and smoothed it very lightly with a very fine slip stone. Much easier now and it hasn't altered the fit..
 
 
John
 

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Few points on some of the comments.
 
The cp2 twister does have the mixing control on the 4 in 1 as per usual. With the trim central on mine the main rotor motor can be heard ticking - just on the point of turning and the mixing control doesn't seem to have any affect. I have found that the trim needs to be moved up towards the central position to get the tail rotor spinning as it should before the main rotor starts up.
 
Using right cyclic on lift of due to gyroscopic effects of tail rotor?  I've not experienced anything of concern due to that. This tip occurred  short of the point where the heli would lift off anyway. My MFA was more likely to be in need of minuscule amounts of left or right tail rotor not cyclic. That one was made when companies did try and make sure that the things they sold worked.
 
On the twister cp I'm getting the impression that it's a case of getting the mechanics right first and then adjusting the mixer on the basis of what happens at lift off.  As per normal really. Problem though the throttle trim may interfere too from what I have seen so far offering a sort of mixer come trim on the fly so as too speak.
 
John
 
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You would experience the tip over to the left as soon as the helicopter begins to become light on the skids. In fact, for a good takeoff, you'll need to force the left skid to take off first, and the helicopter will always hover tipped over slightly to the right. You should have to add right cyclic while still on the ground to prevent tip-over. Check this out, it's one of the most frequently recommended set of instructions on learning to fly a single rotor helicopter:
 
 
It's possible that your previous helicopter had design features to offset this tendency, such as the main shaft tilting to one side, but I would still think you'd have come across it.  You do find that you compensate for it without thinking after a while though.
 
I don't understand why the tail rotor needs to start spinning before the main rotor starts turning.  I don't think my Honey Bee FP does that, and it doesn't cause any problems. As it's still on the ground, the friction between the skids and the surface is enough to hold things steady while you spin up, and the tail rotor catches up pretty quickly. Set the gyro settings on the 4-in-1 for proper behaviour during hovering.
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My 1st reaction to the link is to laugh but I need to start at page 1 and go on from there before I really laugh or maybe change my mind. I certainly haven't noticed the effect you mention - once my heli was correctly set up
 
On spinning up the tail rotor 1st that is as per the instructions that come with a twister cp2. It makes a lot of sense too as the tail is driven by a separate motor which will take time to spin up. The MFA uses a geared drive off the main rotor and variable pitch on the tail rotor for control.
 
On friction with the ground again as per instructions on the cp2 twister and others I will set up for stability with a sufficient amount of lift to very very nearly lift the helicopter off the ground. This is a gradual process. As soon as the heli starts to turn trim it out and allow the setting to settle. Then apply a little more lift trim out again and so on watching to see that it's lifting evenly all the time and trimming that out  with the cyclic trimmers. A training stand is a great help with that aspect. This helicopter flipped instantaneously some way before this stage. I didn't have a stand at the time and had no intention of getting anywhere near lift off. It looked ok and a tiny bit more lift and bang.
 
Next comes the actual lift off and here there is a definite problem of varying degree with all helicopters. As soon as the helicopter starts to lift the air flow increase through the blades and this generates more lift which in turn generates even more air flow and so on. You could say that the blades are stalled/working inefficiently until the helicopter starts to lift. Much the same as the static thrust on a normal aeroplane propeller. It is likely  to be entirely different to the thrust generated when it's actually flying.
 
Once the heli is stable with hardly any load left on the ground the next thing is what happens when it lifts. This is where the mixer should come in. Obviously changing this will alter the earlier trim settings as well. The 2 setting inter react but it doesn't take all that long to sort out.. Once set up it wont always behave entirely perfectly but should be close.
 
As to gyro's it's very easy to see just how effective they are. Disconnect the main motor, fire it all up, put some throttle on if there is a tail rotor motor and then swing the helicopter about it's vertical axis at various speed. Varying jerks would be a better description in some ways. You will see the effects with a variable pitch tail rotor and hear/see the effects  if it uses a separate tail motor. You should also see something happening with a twin rotor craft.
 
The Cp2 settings out of the box are interesting. The part that moves for cp is central with the throttle  trim set central as well but it's a good way of centre with the throttle trim where it needs to be.
 
Personally I don't think it pays to take information on the web as gospel. It often isn't. Those links I posted need some thought. The comment on the motor managing to reach full speed is a very interesting one though, My cp2 wont. Full throttle actually causes the low volts warning to come on and the speed to drop. This could well be down to too much pitch. To much of that and the blades will act like paddles. The effect is so sudden I am fairly sure they are behaving just like that but this could be down to the fact that the heli isn't lifting.
 
Likewise on the links should the pitch be zero with throttle in the middle and the 3d switch on? Makes sense in some ways but clearly negative pitch wouldn't be a good idea. A sudden drop in pitch might not be such a good idea either. I'm inclined to think the pitch shouldn't change at all if throttle in the middle and the switch is used. Only way to find out is to try it.
 
John

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Posted by Ajohnw on 22/07/2010 00:59:21:
My 1st reaction to the link is to laugh but I need to start at page 1 and go on from there before I really laugh or maybe change my mind. I certainly haven't noticed the effect you mention - once my heli was correctly set up

Assuming you mean the heli leaning to the right when hovering then yes - that effect is very real.  On most model helis the blades rotate clockwise (viewed from above) and the tail rotor is pulling the tail to the left to prevent the heli from rotating.  However as well as stopping the heli rotating,  this force also pulls the entire heli to the left,  so when hovering the heli must lean slightly to the right to remain stationary.
 
 
Posted by Ajohnw on 22/07/2010 00:59:21:
Likewise on the links should the pitch be zero with throttle in the middle and the 3d switch on? Makes sense in some ways but clearly negative pitch wouldn't be a good idea. A sudden drop in pitch might not be such a good idea either. I'm inclined to think the pitch shouldn't change at all if throttle in the middle and the switch is used. Only way to find out is to try it.

 
The "3d switch" is normally called the "idle-up" switch, and in idle-up mode (3d switch ON) it would be normal to have zero degrees pitch at the centre of  the throttle/collective stick.  You then have equal positive and negative pitch for stick movements either side of the centre which is what you want for inverted flying.  This of course is some way into the future for you at the moment! 
 
Conventional advice is to have the pitch set to 6 degrees - which is about where the heli will hover - at centre stick for normal mode (3d switch OFF.)  There will be a change in pitch when switching between modes (3d switch on or off) and for that reason my local heli gurus recommended me to use broadly the same pitch curve with idle-up on and off - however that is not the advice you will normally see.  My heli hovers at around 2/3 stick.
 
 

 

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Ajohnw,
 
Yes, the style of Radd's school of rotary flight is somewhat daft (!) but the substance is good.
 
Sorry, yes, I wasn't totally accurate in what I said about the tipping left and the tail rotor force.  Firstly it isn't a gyroscopic force, as John Privett points out, it's the imbalance of forces directly created by the tail rotor. If something's pushing the heli left, there needs to be some force to the right to balance it. Initially you have to tilt the rotor right while taking off to achieve this. Once in flight, the heli just sits tilted. Secondly, it doesn't actually tip the heli, it pushes it laterally left, though if you skids stick on something it will tip it over.
 
Regarding making the tail rotor spin first, I can't really comment on the Twister instructions as I have a Honey Bee, but it seems unnecessary to me. You'll notice in one of the links you posted (http://www.youtube.com/watch?v=Cc_l0PDZHps) that the guy actually holds the stick right to make the tail rotor spin first. He actually ends up with the heli turning clockwise on takeoff as he takes off holding the rudder stick right. So long as you spin up gradually the gyro is more than capable of holding the tail steady for you, and will start spinning the tail rotor when necessary. At least that's how it is on my HBFP, and I'm using the mixer/gyro out of a CP2, frankensteined together with a Spektrum Rx.
 
I'm not convinced that you need the throttle trim set to the bottom. I've not needed to do this. If it's just to arm the ESC/mixer/gyro unit, you could lower the trim, then put it back to central. This will solve the issue with the pitch being off zero at mid-throttle.
 
If you experience the pitch increasing rapidly rather than gradually you might have a sticky collective problem. I wouldn't expect to get the low voltage warning with a fresh battery unless the pitch is too high. What Tx are you using? If it's stock, the pitch curve ought to be set up right as is :-/
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You may find this page useful for some of the setup:
 
 
As the page is about the HBFP only certain parts will apply, but the gyro setup instructions should help you a lot.
 
Also see the next section on the page, the FAQ, as it explains about the right cyclic during lift-off and why you don't want to trim it for neutral behaviour while on the skids.
 
As with all info on the web, it's not guaranteed to be right, but it's a wiki, so errors tend to get corrected over time. I used this page to set up my HBFP and it was spot on. There is a lot of useful info that will relate to the 4-in-1 and tail rotor design that your heli shares.
 

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Being fair to your 1st link David I think he assumes that the heli is already trimmed out at least on the ground. The pages do provide some useful clues though eg balancing the blades out to individually before balancing the usual way or at least checking them.
 
The suggestion of turning the gyro gain down while setting up the mixer on the wiki is interesting too. The gyro setting of a little before the tail wags is the same as the instructions that come with other esky heli's I have seen. There's none of this sort of information with the twister cp. I've seen many comments that the on the box statement "has been test flown" is entirely incorrect. Not so sure. I think the problems in that direction may be that if a person sits on the end of a production line all day testing heli's they will soon manage to fly anything. A statement like trimmed out to hover with all trims central would be much better - in our dreams.
 
On swash plate settings in the two modes I'm really trying to find a method of checking that pitch is where it aught to be.  The fact that the swash mechanism is central with the trimmer also set central with 3d on concerns me. The heli wont always power up like that as it detects main rotor power.  Set the trim right down it powers up ok but pitch goes negative when the 3d switch is used.  I just checked if the pitch can be set to zero with the throttle trimmer but it's still slightly negative with the trim right up. I did have  the throttle stick central when I tried this. Slight mod needed to this paragraph - since I stoned out the rough edges on the hole in the engine shaft the swash remains central in both modes  providing the throttle trimmer's central as well. It must have been sticking due to being forced on.  I'm beginning to wonder if the tail and main rotor motors are plugged the wrong way round. Trouble is though that swapping them may overload the tail drive and let the smoke out. (All electronics work due to smoke as they stop working when it comes out.) This and a miss set static pitch might explain the trim settings needed to get it to work as per the book. The mixer gain doesn't seem to affect this aspect.
 
 
John

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No, don't let the magic smoke out! It's very hard to squeeze back in!
 
I think you should be able to tell if the motors are connected to each other's connectors. Try disconnecting the main motor, putting the throttle to just about a quarter (idle up off) and rotate the helicopter about the axis of the main shaft. The tail should spin faster (you should be able to hear it) when you turn the heli counter-clockwise (from above) in response to the gyro.
 
As I understand it, the proportional setting on the gyro fine tunes what the gyro thinks is zero rotation. This is what is adjusted to remove tail drift. The gain setting adjusts how ratio of rotation to tail speed, thus affecting how fast it tries to stop rotation. When this is too high, there is overshoot leading to a wagging tail. When the gain is too low, the tail hold would be less solid than it could be I think.
 
You are talking about a mixer gain. I'm not sure I understand what this is - the gain on the 4-in-1 is for the gyro, and doesn't affect the CCPM mixing (which I believe is done in the Tx). What Tx are you using? The supplied one? If so, I think the only way to adjust the collective pitch independently of the throttle is to adjust the pitch links, though others might correct me on that.
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Doh I had already checked the gyro that way so motors must be connected correctly. Forgot that thanks for pointing it out..
 
On the mixer gain I tried adjusting it to see if it would help get the tail rotor up and running correctly before the main rotor starts spinning, It doesn't seem to have any effect on that only the speed of the tail rotor when the main is running. To be expected I suppose as some fraction of zero is still zero but there might have been some interaction in the circuitry.
 
I'm using the supplied transmitter.
 
The blades are off at the  moment to tidy up an small epoxy repair to the end of one of the main blades and then rebalance them correctly. I'm also berating the ebay seller on the fact that one of the blades was reversed plus the other oddities.
 
I'm left in an unhappy situation. With 3d on etc there is negative pitch, this suggests the pitch needs increasing. At full throttle the motor can't cope suggesting too much pitch - that could be down to lack of airflow generated by lift as I am holding the heli in my hand. (Blades above my head or at least not at eye level)
 
Being a glutton for punishment  I'm picking up an esky cp belt tomorrow with pitch guage and one or too other bits and pieces which should help check the the cp2 out  further. The cp2 turns out to be a cp2.1 by the way. Following that check I'm going to give it  a go again and see what happens. If it's stupid it's going back to the seller. The esky is very reasonably priced but lacks a battery. I consider it a decent purchase as the major components would cost far more than I am paying for it and I intend going in the larger direction at some point anyway. Probably more sensible than trying to electrify the MFA even though I'm sorely tempted. All part of a long term curiosity about model helicopters.
 
2 things I've noticed that might be worth passing on.
 
The main engine shaft is one piece with the gear that drives it on my cp2. Not good, fair bit of dismantling to replace also more expensive. Could be that gold parts fit. These seem to have  a separate shaft and gear.
 
When balancing the blades I used a wicks spirit level packed up to be level as a reference. Easy to check if the level is ok. Place on some surface, note bubble position which may not be central, swinging the level round through 180 degrees should give an equal and opposite displacement of the bubble if the surface it's on isn't level. I always try that in the shop before I buy.
 
On the micro twister I'm inclined to think that it would make a very good sensible 1st time step into helicopters even though a controlled yaw left or right of a few degrees is rather challenging to say the least. It also uses infa read for control but that isn't too much of a problem really especially in doors. I fly mine round the bedroom for  a few mins before I get up each morning. Excellent practice. It sometimes takes rather a long time for the throttle to start working so watch out for that.
 
John

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  • 3 weeks later...
This helicopter gets worse. It was supplied with the tail motor reversed. Fixed that, balanced the blades and checked tracking and it's the most unstable one I have tried to date. Me thinks there is a fault some where. Looking at cost plus spares it would have been better to buy a new one.
 
John

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  • 8 years later...

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