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-   -   Blade SR 120 - is TBE normal out of the box? (http://www.rcuniverse.com/forum/rc-helicopter-beginners-forum-165/10609644-blade-sr-120-tbe-normal-out-box.html)

Jesse Gordon 07-06-2011 10:36 PM

Blade SR 120 - is TBE normal out of the box?
 
Good Day,

I'm learning to fly my first single rotor heli the Blade SR 120. However, it will not hover for more then a second or so before it builds up to a significant cyclic orbit pattern while maintaining heading lock is that called TBE?

It's bad enough that if I don't correct for it on the fly, after 10 or 20 seconds, it's going faster and faster around, banking 45 degrees because it's going so fast in circles. It doesn't seem to actually crash as long as I keep compensating the throttle, but it makes it hard learn to fly slow when the thing wants to go fast in circles around my head!

If I give it corrective input it stops the nonsense and hovers steady for around a second, but then starts up again, slowly at first then faster and faster.

On fast flight it works fine, but I'm really not skilled enough to do fast flights very well.

Sooo my question is whether this is normal behavior for an SR120 or if they can hover steady.

(I flew a good bit of micro coaxial before the SR120 so I know what's normal for sideways drift due to poor trim or air currents. I have a Syma 006 which was cheap as dirt in construction but steady as a rock and actually loads of fun for the $35 it cost me. I even modified it, replacing the lower blades with E-Flight blades & swashplate.)

Because this is my first Single Rotor heli, I have no idea what to expect, whether TBE is normal and I just need to grow up and fly fast/continually correct, or whether mine needs an adjustment.

Thank you so much!

Jesse

PS: This little birdie really is a whole lot of fun!

rem0.061 07-07-2011 07:07 AM

RE: Blade SR 120 - is TBE normal out of the box?
 
I had the same problem with the msr; it must be a design flaw. So I would say this is normal behavior for the sr120. However, you will find that alot of helis don't like to stay in a hover for too long. when you move up to cp helis this tendency to hover in a circle will go away, but you will still have to be on the sticks at all times.

Jesse Gordon 07-10-2011 09:18 AM

RE: Blade SR 120 - is TBE normal out of the box?
 
Thank you rem0.061!

I am interested in CP helis, but of course figured I should get the feel on a cheaper SR to slightly increase my time till first total smash of a more expensive CP heli.

Can you explain a little what flying a good CP heli is like as far as having to always keep on the sticks? From a mathematical standpoint (and from coaxial experience) I'm aware of vertical drift where the operator must keep constant control of collective so the birdie doesn't go too high or too low, and I'm also aware of horizontal drift due to either out of trim conditions or crosswind or churning air currents if inside a small room :-).

But other then those, what characteristics are exhibited by a CP heli which create a challenge for a beginner to hover? If one's flying in a large open flat grassy field with no wind on a dry day and the heli is trimmed out perfectly, does it not hover pretty steady as long as collective is controlled to maintain steady altitude? Or does it also still get in some sort of oscillation due to the dynamics of flybar or something?

I suppose a flybarless CP heli with effective rate gyros would be the least likely to get into some oscillation, (But also the most expensive :-)

Thanks very much,

Jesse

madmorgan 07-10-2011 03:55 PM

RE: Blade SR 120 - is TBE normal out of the box?
 
you shoulda just went ahead with a 3d machine them intermediate birds are a big waste imho u shoulda started with mcpx its a cool lil guy and nearly indestructible

Jesse Gordon 07-10-2011 06:00 PM

RE: Blade SR 120 - is TBE normal out of the box?
 
Thanks for the suggestion! I had no idea an mcpx was so affordable! My local hobby store had one for around $500 but of course I wasn't about to learn & burn on that one.

Can you tell me a little more about the mcpx and how it flies? If trimmed out, will it hover steady if I keep the collective correct for constant altitude? I don't mind mild drift due to non-exact trim or a crossbreeze, but cyclic circling or some run-away, oscillating or self-feeding instability condition is what I'm asking about.

If it's trimmed out, and I'm flying forward at a nice speed and I let go of the cyclic stick will it level out, or does it maintain pitch lock and require me (for example) to pull back on the cyclic stick to cancel out a previous forward push on the cyclic stick?

Thank you very much!

Jesse

rcheliguy2 07-11-2011 03:39 AM

RE: Blade SR 120 - is TBE normal out of the box?
 
i totally agree with u on the syma they make extremley stable coaxials and 3 chs. i also had no idea that you could modify it. as for the 120 sr, i am still on the msr, and sometimes have a more mild form of the problem, but usually it is quite stable. I am thinking of making a youtube video called "things that we can do with the msr hands off hovering" J K-inghttp://www.rcuniverse.com/forum/js/f...wink_smile.gif

madmorgan 07-11-2011 06:02 AM

RE: Blade SR 120 - is TBE normal out of the box?
 
i have the bnf version of the mcpx as i have to many radios already i went through alot of threads on mods and fixes alot of them are easy and well affordable 500 doesnt sound like a good deal  i paid like 135 for my bnf but the hs i bought it from always knocks money off everything. i would say the bullet blades are better for like hovers and fwd flight  theres alot out there that complain of tail blowout etc i wouldnt know im not into the hardcore 3d i can tell you i did a inverted hover for the first time ever and pulled out of it with no probs even in high winds this thing is pretty stable ive had it in 10 mph didnt even hardly notice. do a search on other threads about mods and fixes then u make the decision. but i can tell you 1 thing ive had hard nose in crashes etc etc u pop off the skids push the main gear back up check you didnt lose or pop off the blade links reassemble and fly i have broken a few links like i say i lose the lil suckers more often than breaking though. i have yet to break either set of main blades "knock on wood" as far as hovers ive had it up 6 ft trimmed out controls and let go of sticks and she will almost maintain a perfect hover in no wind ofcourse

twoslick2 07-11-2011 02:21 PM

RE: Blade SR 120 - is TBE normal out of the box?
 
Has anyone had any experience changing the tail boom on the sr 120? How hard is it to do? I looked on youtube for a vid but had no luck finding it Thanks!

Jesse Gordon 07-12-2011 12:05 AM

RE: Blade SR 120 - is TBE normal out of the box?
 

Quote:

ORIGINAL: madmorgan

you shoulda just went ahead with a 3d machine them intermediate birds are a big waste imho u shoulda started with mcpx its a cool lil guy and nearly indestructible
I went back and checked and my local RC Hobbies had the mcpx BNF for $179.99 so I got it. Of course it was dark by the time I got a chance to fly, so I hopped it around in the house for a bit then tried to fly it in the cow pasture in the dark but there's a breeze, and it's hard to tell which way its going, so I'll have to wait..

But it has a totally new feel. I haven't detected any cyclic circling at all. (Of course I've only flown it for a few seconds at a time.)

Thanks!

Jesse

madmorgan 07-12-2011 01:29 PM

RE: Blade SR 120 - is TBE normal out of the box?
 
welcome to cp jesse nice to hear that make sure u check the mods like painting the little arms that connect to blade grips and when you notice when tryin to take off the blades start to vibrate that means the gear is loose just push it back up into place. the cut grommet that holds the connectors your painting is a big differance in performance too. im getting rdy to clean my servos as they tend to get dirty. just have fun and dont get discouraged every1 crashes just some more than others lol

Jesse Gordon 07-13-2011 10:44 PM

RE: Blade SR 120 - is TBE normal out of the box?
 
Thanks for the encouragement, madmorgan.

I still haven't found a time and place for more then 1 or 2 second flights, but I'm learning in short hops right now.

I have a DX6i which allows me to set gyro gain but that doesn't seem to have any influence for the mpcx, so maybe it doesn't support that.

First, I've gotta say, the power of the gyros on this thing is amazing. I can drive it around skidding it on a smooth floor tilted up, sliding on a single runner end.

However, I've noticed something very strange. When the tail & main motors are not running, the swashplate control is under regular proportional control by the left-hand stick with the gyros providing corrections for sudden movements, just like I would expect. However, as I throttle up, as soon as either of the rotor motors start to spin, the swash plate switches to rate-mode, where swashplate position is no longer proportional to stick input, but rather stick input controls rate of change the further forward you push the stick, the faster forward the heli tilts. When you let go, it holds the heli there. You have to pull back, to level it back out.

I guess this makes sense in one way, it's basically heading-lock for all 3 axis, and the trim functions no longer trim the way one would expect.

There also seems to be a bit of a deadzone which makes it hard to exactly control direction at low speeds, although this sensation may be just new user syndrome.

But on the other hand, it's a little tricky to learn to fly since you're controlling the rate of angle change rather then the angle.

I'd like to find a way to switch it to be such that the swashplate stick proportionally controlled the pitch of the heli (which would not be good for stunts, and which would not work due to gyro drift) or such that the stick proportionally controlled heli-to-swashplate angle, with the gyros to cancel sudden movements not caused by the operator. (This mode should be quite workable then hover could be trimmed out. Sort of like the way a coaxial with a flybar works - except using the solid state gyros to replace the flybar.)

Anyway, all very interesting. Any tips or ramble about CP heli's for newbie CPer's would be most appreciated!

Thanks,

Jesse


PS: I did set up my transmitter according to the MPCX instruction book, and then toned down the throttle curve a bit. But it is possible I missed something and the behavior of heading lock in all three axis is a result of my misconfiguration of my transmitter.

madmorgan 07-14-2011 03:03 AM

RE: Blade SR 120 - is TBE normal out of the box?
 
ok heres what i learned about the mcpx when taking off spool her up easy if you notice the bird is leaning left right fwd or back slowly move the opposite to get it level the servos dont recenter like a normal servo i believe the board for the flybarless is the reason . so once your happy with it all level taking off keep moving collective up once u see the skids getting light give her a bit more and get it off the ground the gyro doesnt have much effect on the ground esp in bigger helis like the b400 trex etc etc  dont be afraid to get it 4 ft up i know the heart starts racing but ive found if i put the headphones on or turn music on it controls this excitement . its a very tuff bird !! you will also notice it will want to slip left on take off this is normal you will get use to it and learn how to compensate for it by moving your right stick ever so slightly to right . if your hopping  this tells me your to heavy on your collective up and down. nice fluid motion is what you want. some people fly with thumb and pointer other like me use just thumbs but im trying to learn the thumb and pointer much more control doing it this way. just take it easy get it off the ground and remember if just hovering you need only small inputs on the sticks when u start getting into fwd flight etc then you have to start working the collective to compensate to keep height when you move the right stick as the bird will start to lose some altitude. dont be afraid if u mess up the little guy is very forgiving

Jesse Gordon 07-14-2011 07:22 AM

RE: Blade SR 120 - is TBE normal out of the box?
 
Thanks!

By "Hopping" I mean that I fly it up to 6 to 12 inches on the kitchen floor, and fly it as long as I can before it runs into a wall or appliance, then I set it back down, and reposition it to the center of the kitchen, and try again.

It's taking me a while to get the hang of changing directions in a timely manner :-)

(The right-hand stick seems to have some deadzone such that I start pushing it a little bit at a time but the heli doesn't respond until I go far enough. It's very small of a deadzone, but I have to push slowly or when I'm out of the deadzone, the heli will change directions too fast.)

I'll also try flying it with a less drastic pitch curve since I do notice the collective is very active, and since I'm not doing aerobatics yet, I don't need full pitch throw.

Thanks again,

Jesse

madmorgan 07-15-2011 11:30 AM

RE: Blade SR 120 - is TBE normal out of the box?
 
did you put in any expo in that dx6 jesse?

Jesse Gordon 07-18-2011 07:23 PM

RE: Blade SR 120 - is TBE normal out of the box?
 
Madmorgan,

Yes, I put 30% expo in my dx6i as instructed by the MPCX instruction manual.

Last night I got a chance to fly indoors in a 20x25 foot room! It was lots of fun! Still very challenging, but I was able to fly for 20 seconds at a time! (Yeah yeah, okay I'm a beginner! I know 20 seconds is nothing, except it was a first for me on the MPCX!)

I did end up breaking a ball on the swashplate so I gotta replace the swashplate.

Thanks,

-Jesse

madmorgan 07-21-2011 02:32 PM

RE: Blade SR 120 - is TBE normal out of the box?
 
try cutting that expo down a bit so it reacts to your commands im around 15 % but there again its all about preference . its up to you but you can just turn the swash to next set of balls to keep flying as it has 4 then pick up another but there again its your money. you will find it gets easier and easier then boring just hovering if u keep at it you will be in fwd flight before you know it lol. remember once u master tail in hovers next its nose in very intimidating in real life ofcourse i can nose in hover on realflight no probs when it comes to real  life it gets sketchy lol.

Jesse Gordon 07-22-2011 10:33 PM

RE: Blade SR 120 - is TBE normal out of the box?
 

Quote:

ORIGINAL: madmorgan

<snip>.... its up to you but you can just turn the swash to next set of balls to keep flying as it has 4 then pick up another but there again its your money.<snip>
Thanks for all the helpful suggestions! Unfortunately, the ball on the swashplate that broke off was on the non-rotating part it was the ball that connects to one of the servo push rods.


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