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Old May 14, 2012, 08:19 AM
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I can empathise with N. of 49's feelings about not wanting to put money out on the mCPX. I really have no interest in it myself due to it's postage stamp size.

That having been said, I'm afraid I'm going to have to do just that. I don't think I have a powerful enough computer to run any sort of sim (I'm not a PC gamer) And I'm not about to upgrade my computer just for that purpose.

As much as I feel I'm quite proficient with the 120SR, I'm afraid I would be in for an ego-busting (if not downright bank-busting) experience if I tried to transition directly to the 130x.

So I guess if I have any real designs on getting into the world of CP, I'm going to have to swallow one more pill and get myself an mCPX.
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Old May 14, 2012, 09:03 AM
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United States, WA, Port Angeles
Joined Nov 2010
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I can't argue with the crash survivability of the mcpx and it was a good little heli, i just didn't have any interest in flying it after a while. All i fly now are my fbl 400 and my trex 600. And no, i don't crash them, but i don't do stupid stuff with them either. I practice at altitude and then move lower. My 400 is setup with the zyx fbl unit with a 5084mg tail servo and its rock solid. Powerfull even with the stock motor and tail does not blowout ever. This allows me to learn things the right way without compensating for bad tendencies in the heli.
Either way you decide on the mcpx i would still say to get good you will need a sim. Just depends on how people want to fly. Getting away from the computer and getting outside is always a good thing but there is just no substitute for a sim.
One thing about the mcpx is it still holds its value well. I bought it at discount at ampdraw hobbies and i only lost $20 when i sold it here on the classifieds. Probably some of the cheapest fun i've had in this hobby.
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Old May 14, 2012, 05:38 PM
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United States, FL, Clearwater
Joined Jun 2009
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After reading the past page or so (as I have been following this thread for a little while now), I can't think of why I have seen hardly anyone mention the fact that even thought the 130X is bigger and therefore heavier, it is because of its mass that it will be more inherently stable than the much smaller mCPX. I too never really liked the tiny size of the mCP X, though I can say that I have seen and have flown a mCP X thanks to a pilot friend of mine. Smaller = squirellier handling due to any wind currents. It's really a give and take... smaller is more durable, but it's much more of a "handful" in the air.

Since I have owned a 450 class heli now for just about a year and have felt the difference in the air the difference between it and a 600 class (again thanks to my buddy), my point is proven. I do realize the difference between a 450 class heli and a 600 class is much more significant, but it only makes sense that a heli with a bigger rotor-span will behave in a much more stable manner than one that has a smaller disk.

To put the first 2 paragraphs in a nutshell, the more stable heavier heli is a better platform to learn from, though it will admittedly cost more to replace any parts lost due to a crash. I really do now wish that I had gone right to a 500 or even a 550 (like I will be getting next month), rather than the 450 I started out with.
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Old May 14, 2012, 07:00 PM
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Originally Posted by jscott1 View Post
True the 130x and the 120SR in stock form are virtually the same mass. The real difference is the head speed. The symmetrical blades on the 130X require significantly more head speed to achieve the same amount of lift. Also higher head speed is part of the design because it increases the stability and control in flight. The 120SR has a tendency to balloon up when a gust of wind hits it.

As a result the 130X will respond significantly faster to the controls than an FP helicopter. And we haven't even addressed the lack of the 45 degree flybar and lack of self-correction in hover...but I'm sure you know all about that.
The symmetrical blades in and of themselves do not require a higher headspeed for the same lift as the FP blades on the 120SR. You can always increase the blade pitch to get more lift for a given head speed. The higher head speed can improve stability.

Because the 130X uses the electronics for stability and control response it most likely can be tuned to more or less replicate the response of the 120SR. I would guess that this might be the initial setup. Once you get used to it, you can then adjust the setup to make it more sporting.

The 3-axis stability system removes the requirement for the flybar. The servos may be beefed up to handle the extra load required to adjust the blade angle directly.
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Old May 14, 2012, 08:22 PM
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A great FP trainer for a CP is the walkera V120d01. It is not "self stabilizing" like helis with a 45 degree flybar. I was able to go from this heli to a flybar gaui 200.

I would agree that going from a 120SR to a small CP would be tough, but it depends on the stabilization system of the CP. Very hard to go from there to a flybar gaui 200, but not so hard to go from there to say a walkera v120D02s. And I bet the 130 has at least a just as good better stabilization system than the v120d02s...

If you get a sim then anything is possible...

Chief
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Old May 14, 2012, 08:51 PM
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Malaysia, Penang, Bayan Lepas
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Originally Posted by ssobol View Post
The symmetrical blades in and of themselves do not require a higher headspeed for the same lift as the FP blades on the 120SR. You can always increase the blade pitch to get more lift for a given head speed. The higher head speed can improve stability.

Because the 130X uses the electronics for stability and control response it most likely can be tuned to more or less replicate the response of the 120SR. I would guess that this might be the initial setup. Once you get used to it, you can then adjust the setup to make it more sporting.

The 3-axis stability system removes the requirement for the flybar. The servos may be beefed up to handle the extra load required to adjust the blade angle directly.
I think you're not getting what these people are trying to say here.
You can't just increase pitch without adding headspeed, it is going to bog the motor down and cause the heli to fly like crap (believe me, I tried to push my 250 down to about 2k RPM, unstable as hell and are all over the place, same for my 4G6S).

The 3 axis does not self stabilize. Inherent nature of 45 degrees flybar (120sr) is that when you release the aileron and elevator, it self stabilize (locks back into hover), but in 90 degrees flybar or 3 axis stabilization system, they don't. They'll continue the heading of the last command.
My suggestion is that try out some sim (even free ones), and you'll see how flying CP is different from flying 45 degrees FP. For FBL FP or 90 degrees FP, they're quite similar to 130x. That's my 2c.

FYI, I had flew 45 degrees FP (NE solo), 90 degrees FP (4#6), 90 degrees CP (4G6S, Trex250), and FBL CP (v120d02s)...

Hope this helps...
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Old May 14, 2012, 09:09 PM
Yes, I know it's upside down.
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Joined Dec 2008
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Originally Posted by Coptafeel View Post
That having been said, I'm afraid I'm going to have to do just that. I don't think I have a powerful enough computer to run any sort of sim (I'm not a PC gamer) And I'm not about to upgrade my computer just for that purpose.
I run a 6 year old laptop that is not a gaming computer and my sims (AeroFlyProDeluxe and Pheonix) run fine. You just need to turn off things like water reflections, smoke, etc.
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Old May 14, 2012, 09:14 PM
Yes, I know it's upside down.
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Originally Posted by everydayflyer View Post
Two years ago I shelfed my Blade 400 due to rebuild cost and time. One dum thum move equaled $50 to $100 in parts and hours of rebuilding and re tuning.
Getting a little off topic here, but have you tried flybarless? Converted my 450 recently, and rebuild times and costs are now dramatically reduced. Once you're past the initial setup, most crash repairs involve little more than replacing a main gear, bent shaft and blades, and then checking your blade tracking. All that fiddley, sloppy flybar stuff that takes all day to tune is gone and is replaced with two simple links.
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Old May 14, 2012, 09:16 PM
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Thanks, Harrow!....I guess I'll have to check in to a sim then.
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Old May 14, 2012, 10:35 PM
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Originally Posted by thloh85 View Post
You can't just increase pitch without adding headspeed, it is going to bog the motor down and cause the heli to fly like crap (believe me, I tried to push my 250 down to about 2k RPM, unstable as hell and are all over the place, same for my 4G6S).
This is true, but the easiest solution is to cut down the blades so that the headspeed remains high at increased pitch.

Some have also successfully set up the MCPx and other helis as fixed pitch helis by using a flat pitch curve on their transmitter.
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Old May 14, 2012, 11:12 PM
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Originally Posted by thloh85 View Post
I think you're not getting what these people are trying to say here.
You can't just increase pitch without adding headspeed, it is going to bog the motor down and cause the heli to fly like crap (believe me, I tried to push my 250 down to about 2k RPM, unstable as hell and are all over the place, same for my 4G6S).

Hope this helps...
Yes, as you increase pitch the motor load increases so the head will slow down. However, if you have some sort of governor you can increase the motor torque to recover the initial headspeed. A motor of sufficient torque will maintain the headspeed at the cost of higher battery consumption. If you are using a brushless motor it is fairly simple to add a governor. Setting the throttle curve attempts to do this but without direct feedback. (In the old days throttle curves were set up using a tachometer to actually measure the headspeed at different blade angles.)

My point is that a symmetrical blade does not automatically REQUIRE a higher headspeed to get similar lift to a FP blade. You can run a FP blade and a CP blade at the same RPM and get similar lift, but the blades' angle of attack could be different. You may be correct in saying that for a given blade angle a symmetrical blade may require a higher headspeed for a given amount of lift compared to a FP blade. But that is not a rule. When a symmetrical blade is generating lift, it is actually acting as an asymmetric (or FP) blade. The advantage to a symmetrical blade is that it will generate the same amount of thrust relative to the blade disk for a given positive or negative blade angle, just the direction of the lift is different.

There are a number of other reasons why you might run the head faster (more stability, faster response, etc.). You also might run the head slower if you wanted to reduce the damage because of a blade strike or to reduce the size of the servos required.

Different helicopters will have a different sweet spot regarding head speed, stability, control response, and energy consumption. Having the highest headspeed possible is not automatically the best answer in all cases. You could end up making the helicopter too stable (say for 3D), having high speed airflow problems near the blade tips, or requiring servo forces that exceed the available servo size.
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Old May 14, 2012, 11:45 PM
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I think the point has been made that no matter how you slice it the 130X will handle significantly different than a 45 degree flybar.

Yes there was a time in the dark ages when a 450 sized heli was considered small and people started out on big 60 size nitro powered helicopters. You can still do that, but the learning curve is steep and the price of failure is severe. A man was killed at my local flying field when a heli got away from him and struck his instructor, so this is not a game.

http://rc.runryder.com/helicopter/t70830p1/
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Old May 15, 2012, 12:09 AM
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Originally Posted by ssobol View Post
Yes, as you increase pitch the motor load increases so the head will slow down. However, if you have some sort of governor you can increase the motor torque to recover the initial headspeed. A motor of sufficient torque will maintain the headspeed at the cost of higher battery consumption. If you are using a brushless motor it is fairly simple to add a governor. Setting the throttle curve attempts to do this but without direct feedback. (In the old days throttle curves were set up using a tachometer to actually measure the headspeed at different blade angles.)

My point is that a symmetrical blade does not automatically REQUIRE a higher headspeed to get similar lift to a FP blade. You can run a FP blade and a CP blade at the same RPM and get similar lift, but the blades' angle of attack could be different. You may be correct in saying that for a given blade angle a symmetrical blade may require a higher headspeed for a given amount of lift compared to a FP blade. But that is not a rule. When a symmetrical blade is generating lift, it is actually acting as an asymmetric (or FP) blade. The advantage to a symmetrical blade is that it will generate the same amount of thrust relative to the blade disk for a given positive or negative blade angle, just the direction of the lift is different.

There are a number of other reasons why you might run the head faster (more stability, faster response, etc.). You also might run the head slower if you wanted to reduce the damage because of a blade strike or to reduce the size of the servos required.

Different helicopters will have a different sweet spot regarding head speed, stability, control response, and energy consumption. Having the highest headspeed possible is not automatically the best answer in all cases. You could end up making the helicopter too stable (say for 3D), having high speed airflow problems near the blade tips, or requiring servo forces that exceed the available servo size.
I disagree. I tried running my 4G6S with low headspeed (still higher than my 4#6), and increasing the pitch - result is, it flew completely crappy. Reason being - for CP, when you do aileron or elevator, the pitch changes over the rotor disc, while for FP, they don't. This (and a lot other factor) causes the heli the require the headspeed to be higher. I used to think the same as you do (believe me or not), but all my experiments says otherwise (and it made sense if you think thoroughly about it)

Think about it - Why do our fan has the FP like curve? Fan maker could just slap a 45 degrees angled blade and spool it up if curved and flat structure displaces as much air.

And no, adding headspeed will not cause the heli to be "too stable". The reason you think that way is you're too used to self stabilizing heli (45 d flybar). Stability in CP is defined in how much control you have over the heli (ie how responsive).
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Old May 15, 2012, 05:49 AM
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Originally Posted by Coptafeel View Post
Thanks, Harrow!....I guess I'll have to check in to a sim then.
You can try Clearview. It's a relatively small download, and it runs for about 10 minutes for free, then you need to pay $40 to register. Also, Pheonix has a free demo download that you can only watch, not fly, but it would give you a pretty good indication if your computer can handle the graphics.
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Old May 15, 2012, 05:51 AM
Yes, I know it's upside down.
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Originally Posted by Martyn McKinney View Post
This is true, but the easiest solution is to cut down the blades so that the headspeed remains high at increased pitch.

Some have also successfully set up the MCPx and other helis as fixed pitch helis by using a flat pitch curve on their transmitter.
Hmm, never thought of putting my mSR blades on the mCP-X. What a great little experiment. My own flybarless mSR without needing to buy the mSR-X
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