Thinking of buying a Teryx 450 co-axial

[Silverking]

Thanks for all the advice so I have bought an mCPX for use with my DX6i and it should be here tomorrow. Using it and the Phoenix sim I hope to be able to transition to a 450 in due course.

[KevDavies]

Cool Nice 1 mate!! Youll do well with that setup!

[Silverking]

Well that was a learning curve! Set it up as per the manual and it got really weird. Blades spun up but after 50% throttle the motor closed down. Checked everything, rang the supplier (Kings Lynn Model Shop) who were very helpful and think we got there (try a different memory slot). Eventually got it in the air but it immediately flew backwards so hovering in the living room was not an option because this thing is fierce. I have now set the DX6i at the most friendly parameters and I need to fly it in the garden but hovering is a big challenge. So I am learning a lot but I think I need a field to safely understand the mXCP. On the other hand when I did get it in the air it was great.

A question for you. When I run the Phoenix sim should I be able to use the DX6i mCPX settings or do I need to create new ones. Only reason I ask is that at times even the sim would not allow me to take off (and yes I set the reverse pitch to R) so I have this weird combination of real vs sim and one seems to screw up the other.

[KevDavies]

for phoenix you set a blank model and use the settings in the sim, If you look at the instructions on the phoenix site it will tell you exactly how to set up your transmitter for the sim

[tomatwalden]

As Kev says, treat the sim as a different model in your TX. The " settings" for whatever model you choose within the sim are then in effect overlaid on top of the blank settings from the TX.

[Silverking]

Thanks for the Phoenix tip. I think the mCPX is faulty because no matter what settings I use (and I have gone for the mildest I can find and the weighted blades) there is no way the heli will hover. Goes up then diagonally backwards despite all the trims being in neutral. If I have enough space I can catch it and get it flying forwards but it is impossible to get it to hover. Doing a bit of reading here suggests this is a known problem and is due to a faulty main board. Any thoughts?

[KevDavies]

there is a spate of known issues with them, however most helis are like that due to a phenomenon known as ground effect. The turbulent air from the blades makes them do silly things, but when you above waist height the heli will sort itself out. Do you have any expo in the transmitter settings?? Expo will help a lot to learn to hover especially on the smaller machine.

Also what you need to remember is the mcpx is a complete diff kettle of fish from a coax as the co ax pretty much hovers itself, you have to do the work yourself.

Keep at it mate itll click all of a sudden and youll wonder what the fuss is about

[tomatwalden]

I've never heard of a faulty board making an mCPX act like that. Can you provide links? Normally, if a heli drifts, it's because the swash plate isn't level. That's easy to fix by adjusting the swash links.

HOWEVER ... As you're a new to this, I would say if you can, get somebody who can fly already to check it for you if possible as there are two other very simple reasons why this might happen ..

1/. ALL single-rotor helicopters drift left. It's a fact of how they work. It's called translating tendency, and it relies on the pilot to compensate with a bit of right cyclic. If your heli is going left at all, this may be perfectly normal (though it depends on how quickly it goes!)

2/. Front/rear drift could also be caused by the heli not being balanced. On the mcpx, this may be that the LIPO isn't pushed in fully, making it tail-heavy.

Besides all that, CP helicopters are inherently unstable! You have to fly them all the time - you cannot let go and expect the heli to stay still. Only toy co-axials will do that.

Perhaps post a vid if possible ?

[tomatwalden]

there is a spate of known issues with them, however most helis are like that due to a phenomenon known as ground effect. The turbulent air from the blades makes them do silly things, ...

Ground effect, as Kev says, is the heli getting blown about at low altitude by its own rotor-wash. Height is your friend here (about 3 foot in the case of the mcpx)
Translating Tendency is the nature of a single-rotor heli to drift left (due to the tail rotor), most noticable on take off.

Where are you based? Do you have a decent heli store near you?

[Silverking]

Both these threads have my heli's symptoms. Firstly not taking off because it goes to half power and pushing the stick forward reduces power to a stop despite settings being correct and high speed rear movement after take off even 6ft above the ground. I eventually sorted the power issue by setting up a new slot on the Tx but it still happens intermittently. I could cope with a bit of drift but it goes off backwards at about 45 degrees like a demented rabbit.

http://www.rcheliaddict.co.uk/e-flite-mcpx/90926-drifting-backwards.html and Identifying a 3n1 board problem on MCPX - HELP - HeliFreak

Kings Lynn Model Shop have been great and have asked me to return the heli so they can BNF to their DX6i and test fly.

[Silverking]

Sorry - don't think I am being rude but I replied giving links and the next stage in the story but I got a message about my post being "approved by the Moderators" and six hours later it is still not up. Weird Forum you guys have here, albeit very helpful when it works!

Yours, in anticipation.

[Rubber Bullets]

I bought my mCPx last August with a similar history to you, though I did put a single rotor FP in between the coax and the mCPx. It is possible, but I doubt the behaviour you mention is a faulty heli, my Nano also has a tendency to go back and left on take off, it is just a part of the learning curve.

The mCPx is a bit too powerful to learn on indoors, unless you have pretty forgiving furniture and are extremely careful, the Nano is less destructive and so less intimidating to chuck around.

What you could try and do is anticipate the movement of the mCPx and be countering it before it becomes apparent. Don't try to put forward right stick on before the heli takes off, it will confuse the gyros, but pop it up in the air and be applying just a touch of stick to it immediately. Remember to use only very small inputs to the stick, and to let it recentre immediately. If/when you can get it outside you will have loads more space to try this and you will learn so much faster, I did.

RB

[tomatwalden]

Sorry - don't think I am being rude but I replied giving links and the next stage in the story but I got a message about my post being "approved by the Moderators" and six hours later it is still not up. Weird Forum you guys have here, albeit very helpful when it works!

Yours, in anticipation.

Not sure what happened there! Would be good to hear how you're getting on.

[Rubber Bullets]

Sorry - don't think I am being rude but I replied giving links and the next stage in the story but I got a message about my post being "approved by the Moderators" and six hours later it is still not up. Weird Forum you guys have here, albeit very helpful when it works!

Yours, in anticipation.

I've not been on this forum for long, so I don't know, but it is possible that they don't allow new members to post links within the first few posts. Some forums do this to stop spambots from posting dangerous or commercial links. Not that you're a spambot Silverking, or if you are then you're a highly sophisticated one

RB

[Silverking]

There are a couple of threads I linked to one on this Forum, the other on Heli-freaks (try "Identifying a 3n1 board problem on MCPX") relating to faulty mCPX 3in1 main boards that cause erratic motor problems and flying backwards at speed. With the correct settings in the Tx it would only spin up to 50% speed and further stick movement would cause it stop. The shop suggested setting up a new slot on the Tx which did at least solve that problem (although it has happened intermittently since). I then set the DX6i up with the mildest settings I could find but it still will not hover and as soon as it leaves the ground it goes off like a demented rabbit. Contacted the supplier who offered some excellent advice on what to try but nothing worked. They said the would expect the mCPX to hover with some initial drift until it gets to about 3 feet off the ground. Constant forward flying can cause the gyros to get mixed up apparently and the result is it refusing to hover but I never got that far. When I mentioned the faulty board problem they immediately asked for its return so they could BNF to their own Tx, do some diagnostics and report back. Seems like an excellent solution and if it is down to my lack of experience at least I know I have to work at it.