Newbie with SR 120 questions

DaiCa · Posted: Wed Jan 18, 2012 8:08 am Post subject: Newbie with SR 120 questions

I just bought a SR 120 & DX5e last week. I'm completely new to this so any input is greatly appreciated.

1. Charging the battery. The manual says to set it at 0.7A but some YouTube videos say to set it at 0.3A. Which is better?
2. Placing the battery. Do I slide it all the way in or leave it sticking out a little? Does it affect the balance in any way?
3. I centered all the trims: click one way till it beeps, then click the other way 10 clicks. But as I increase the throttle, the nose rotates to the left so I increase the rudder trim to the right until it stops. This requires 9 clicks on right rudder trim. Almost to the max!! Is this normal?
4. As I continue to increase the throttle, it now begins to slide to the left. I saw the post about the tail effect which requires a slight input to the right aileron as it takes off. This I will have to try.

I guess I'm not coordinate enough yet. The guy at the hobby store made it looks so easy. Maybe I should have started with the CX2. Another question: Would switching to the DX6i help in reducing the learning curve?

Thanks in advance.

jcjrogers · Posted: Thu Jan 19, 2012 1:43 am Post subject:

This is coming from another newbie, but this is what I have found being in the same boat as you:

2) I saw somewhere that the 120 SR was better balanced if you didn't slide the battery all the way in. However I found a few problems: 1) the battery tended to slide further out as I flew and 2) the copter seemed more stable with the battery slid all the way in, and 3) even with it slid all the way in, it will still often work itself out. I have gone with pushing all the way in and prefer that over not pushing all the way in for reasons stated.

3) I believe you should start with your trims centered. You know a particular trim is centered when you hear a longer beep. If you are clicking 10 times either way, you have a lot of adjustment on that particular trim. Start in the center and then adjust as needed.

4) I've had it go both ways, in circles, etc. During practice in my den, I've started raising the helicopter quickly to reduce ground effect. Once it is a few feet in the air, I start manipulating it. Though this sometimes results in a quick loss of control and crash, more often than not, it results in a hovering copter that I can control. When I start flying outside, I'll practice lifting more gradual, but in such close quarters and furniture I have to clear, I don't have time to correct a slow lift-off.

nick_onelove · Posted: Thu Jan 19, 2012 2:21 am Post subject:

1) 0.7A is fine. 0.5A would be the safest, 1C charge rate, but I'm pretty sure these batteries can handle it. Mine have for about a year now.

2) I slide mine as far forward as possible for maximum forward speed. If you're mostly hovering, maybe slid back would be more balanced, you'll have to decide for yourself where you like it.

3) I'm not familiar with the DX5e, but 10 clicks seems excessive. Is it possible your tail motor is slowly dying?

4) When you increase the throttle suddenly, the tail motor must also suddenly blow harder to keep the tail steady, this could cause some lateral movement.

If you can afford it absolutely go for a DX6i, you can program in custom dual-rates and exponential to soften or increase the heli's response to your inputs. If you plan on moving on to more advanced helis in the future you're going to need a 6-channel transmitter anyway.

Good luck and welcome to the forum!

jcjrogers · Posted: Thu Jan 19, 2012 8:23 am Post subject:

Regarding your number 3, I was answering thinking you were using the stock transmitter... sorry. I've never used the DX5e so shouldn't have responded.

DaiCa · Posted: Thu Jan 19, 2012 8:32 am Post subject:

Thanks for the replies. I tried it last night in my living room which has carpet and it did not slide to the left before lifting off. It did however wanted to go forward after lift-off so I gave it a bit of backward pitch and it hovered for a few seconds before crashing.

airshot · Posted: Fri Jan 20, 2012 6:47 am Post subject:

Here is how I do it. Center all the trims..connect the transmitter to the heli by binding or plugging in the battery. Look at the swash plate, is it level? front to back and left to right? If not adjust the arm that connects to the servo until you get the swash as level as your eye can see. This is a must when starting out. Operate your pitch and yaw stick to be sure the swash is moving in the correct directions. Slowly engage the throttle and see if the tail motor engages before the heli lifts, if it does then you are ready for liftoff. You need to jump the heli up a few feet to get it above its own rotor wash. If you see it move drastically one way or another drop it down to prevent damage and adjust the correct trims. Keep doing this until the heli pops up and stays in a fairly small area. The rest is "lots" of practice!! Good flyin!

Airshot

admiral · Posted: Fri Jan 20, 2012 6:59 pm Post subject:

Welcome to Forum Airshot,

You have nailed it, could not have said any better, secret to the 120SR is get it in the air, it hates gentle take offs 12" / 30CM off the ground a totally different machine.

jcjrogers · Posted: Fri Jan 20, 2012 11:12 pm Post subject:

How do you manually adjust the swash plate? The manual doesn't mention.

airshot · Posted: Sat Jan 21, 2012 6:23 am Post subject:

You have to carefully unsnap the control rods (black ends) from the swash plate. Those black ends screw on the metal rod, shorten or lengthen until swash sits "very" level. You should find then your trim adj on the transmitter should only have to be adj a few clicks to be spot on..

Airshot

airshot · Posted: Sat Jan 21, 2012 6:26 am Post subject: