Trials and tribulations of my SR120
01-28-2011, 03:34 PM
#1
Trials and tribulations of my SR120
OK, first I am a fixed wing driver. Never really had much interest in rotary winged aircraft.
But got a MCX last winter to fly on those frozen days in wasteland.
So I picked up the 120 SR last week and have enjoyed flying in a local gym since. But it seems like it will turn quite nicely to the right, but has a more difficult time in making sweeping turns to the left. Is this just bad technique, short thumb on the right hand, or something to do with the way these things work?
But got a MCX last winter to fly on those frozen days in wasteland.
So I picked up the 120 SR last week and have enjoyed flying in a local gym since. But it seems like it will turn quite nicely to the right, but has a more difficult time in making sweeping turns to the left. Is this just bad technique, short thumb on the right hand, or something to do with the way these things work?
01-28-2011, 06:21 PM
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RE: Trials and tribulations of my SR120
That's probably correct for any model. It's main blade rotation force that makes it easier to turn to the right than to the left. You can read the theories and much better explanations in other threads.
01-29-2011, 09:40 PM
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RE: Trials and tribulations of my SR120
It's not just you. Mine does it too. I think he's right in saying it has something to do with the way the blades rotate. You'll get used to it. I know it feels weird right now, but it doesn't take long to adapt. It's a fun little thing isn't it? 
01-31-2011, 11:49 AM
#4
RE: Trials and tribulations of my SR120
Yes, I'm currently getting three flights a day in a local gym. I'm to the point where I am dangerous to the survival of the bird.
I'm considering changing the ball joints for greater control and then using the radio (DX8) to compensate with less throw to the right and more to the left to get equal control both ways.
I'm considering changing the ball joints for greater control and then using the radio (DX8) to compensate with less throw to the right and more to the left to get equal control both ways.
01-31-2011, 12:41 PM
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RE: Trials and tribulations of my SR120
ORIGINAL: HighPlains
Yes, I'm currently getting three flights a day in a local gym. I'm to the point where I am dangerous to the survival of the bird.
I'm considering changing the ball joints for greater control and then using the radio (DX8) to compensate with less throw to the right and more to the left to get equal control both ways.
Yes, I'm currently getting three flights a day in a local gym. I'm to the point where I am dangerous to the survival of the bird.
I'm considering changing the ball joints for greater control and then using the radio (DX8) to compensate with less throw to the right and more to the left to get equal control both ways.
The small Fixed Pitch Helis all turn right much nicer than they turn left... eg Blade MSR, 120SR etc..
That is caused by the direction of the blader rotation and the sideways thrust of the tail rotor, and a whole lot of aerodynamics that go along with that...
When you step up to a true collective pitch heli they turn left and right more equally..
As for your 120 SR... using the outer ball joints will definitely help by giving you more roll control.
Can I offer a suggestion....
Don't use your computer radio to compensate for the natural assymetry that is flying a helicopter (even real ones)
Rather, let your body learn the natural muscle memory to make the compensations itself... it may not 'feel' right at first but in no time at all you won't even realise it.
When flying a real helicopter.. changing from forward flight to a hover feels all twisted up initially as you cross controls and compensate for tail rotor drift etc... but that is the nature of the beast and given time and practice your body automatically compensates and you stop being aware of it...
I was a fixed wing RC flyer for 30 years before getting into helis and personally HATED the assymetry at first... but trust me.. you will get used to it..
I was also a Full size fixed wing pilot for 25 years before converting to full size helicopters... man.. what a difference... I hated the feeling of by body feelingall 'twisted' up when slowing down for a landing... (that's the only way I can describe it..) Aircraft are symmetrical, but the heli felt ALL WRONG initially... it was just a matter of getting used to it though... nowI love them and don't even notice the assymetry...
Sorry for the ramble.. .just that I know exactly where you are coming from and exactly what you are feeling with a fixed wing RC background... .... But learn to enjoy the assymetry of the helis for what they are... give it 6 months and I'm sure you will agree with me...
here is my 120 SR...
[youtube]http://www.youtube.com/watch?v=GSYJVoUmPqY[/youtube]
And something more advanced to whet your appetite for later....
[youtube]http://www.youtube.com/watch?v=NfQ_IXVDP5k[/youtube]
02-09-2011, 05:42 PM
#6
RE: Trials and tribulations of my SR120
OK, I now understand the dynamics now as to why it doesn't like bank into the advancing blade during forward flight. I have flown 43 packs now for a total flight time just short of 4 hours. From what I have read, you can fly for about 7 minutes on a pack. However I am limiting time to 5.5 minutes so I only use 80% of the pack. The Control Line stunt guys claim the 80% limit allows the LiPo to last for hundreds of flights without drop off. We will see.
As Rob suggested, I changed the ball links today. It really helps with the left turn problem, and really brings the control system to life. My mistakes are now much less subtle and it is much easier to screw up to the point that I know I am about to crash so it's time to close the throttle. But damn, this thing is fun to learn to fly without breaking anything thus far. My only regret at this point is only having 3 packs at the moment, 5 or 6 would be twice as nice.
I've also managed to fly it outdoors one evening. With the stock ball link position it was a struggle at times with a very light whiff of a breeze. I think with the greater throw it will handle quite a bit more breeze. But it's going to have to be 50 degrees warmer before that happens.
I'd like to see some hop-up parts for this machine. A 90 degree flybar would be nice.
As Rob suggested, I changed the ball links today. It really helps with the left turn problem, and really brings the control system to life. My mistakes are now much less subtle and it is much easier to screw up to the point that I know I am about to crash so it's time to close the throttle. But damn, this thing is fun to learn to fly without breaking anything thus far. My only regret at this point is only having 3 packs at the moment, 5 or 6 would be twice as nice.
I've also managed to fly it outdoors one evening. With the stock ball link position it was a struggle at times with a very light whiff of a breeze. I think with the greater throw it will handle quite a bit more breeze. But it's going to have to be 50 degrees warmer before that happens.
I'd like to see some hop-up parts for this machine. A 90 degree flybar would be nice.
02-10-2011, 06:06 AM
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RE: Trials and tribulations of my SR120
ORIGINAL: HighPlains
OK, I now understand the dynamics now as to why it doesn't like bank into the advancing blade during forward flight. I have flown 43 packs now for a total flight time just short of 4 hours. From what I have read, you can fly for about 7 minutes on a pack. However I am limiting time to 5.5 minutes so I only use 80% of the pack. The Control Line stunt guys claim the 80% limit allows the LiPo to last for hundreds of flights without drop off. We will see.
As Rob suggested, I changed the ball links today. It really helps with the left turn problem, and really brings the control system to life. My mistakes are now much less subtle and it is much easier to screw up to the point that I know I am about to crash so it's time to close the throttle. But damn, this thing is fun to learn to fly without breaking anything thus far. My only regret at this point is only having 3 packs at the moment, 5 or 6 would be twice as nice.
I've also managed to fly it outdoors one evening. With the stock ball link position it was a struggle at times with a very light whiff of a breeze. I think with the greater throw it will handle quite a bit more breeze. But it's going to have to be 50 degrees warmer before that happens.
I'd like to see some hop-up parts for this machine. A 90 degree flybar would be nice.
OK, I now understand the dynamics now as to why it doesn't like bank into the advancing blade during forward flight. I have flown 43 packs now for a total flight time just short of 4 hours. From what I have read, you can fly for about 7 minutes on a pack. However I am limiting time to 5.5 minutes so I only use 80% of the pack. The Control Line stunt guys claim the 80% limit allows the LiPo to last for hundreds of flights without drop off. We will see.
As Rob suggested, I changed the ball links today. It really helps with the left turn problem, and really brings the control system to life. My mistakes are now much less subtle and it is much easier to screw up to the point that I know I am about to crash so it's time to close the throttle. But damn, this thing is fun to learn to fly without breaking anything thus far. My only regret at this point is only having 3 packs at the moment, 5 or 6 would be twice as nice.
I've also managed to fly it outdoors one evening. With the stock ball link position it was a struggle at times with a very light whiff of a breeze. I think with the greater throw it will handle quite a bit more breeze. But it's going to have to be 50 degrees warmer before that happens.
I'd like to see some hop-up parts for this machine. A 90 degree flybar would be nice.
I was in Wichita Kansas 2 weeks ago for 6 days.... Flight Safety training....
You are doing the right thinglimiting the LiPo use to 80% of the pack.. they will last much longer that way...
The MSR is a great heli but doesn't really need hop up parts... Mine has over 600 flights and is still going strong.. all stock..
Here is a video I made flying it around the house last night..
[youtube]http://www.youtube.com/watch?v=ASC9akSqQxw[/youtube]
Fly it to the point were yourun out of challenges and then you are ready for a CP heli.. once you move up to 450 size helis you are really going to have some fun...
I have flown my 450's about 40 times in the last 48 hours.. and can't wait for sunrise to fly them again...
[youtube]http://www.youtube.com/watch?v=H5AeH48c5Rg[/youtube]
02-14-2011, 11:54 PM
#8
RE: Trials and tribulations of my SR120
Well I have flown 64 packs for over 5 1/2 hours and things are still flying in formation. Since duty is shared between 3 actual packs, that is 21 charge/discharge cycles with no hint of performance drop-off. I did smack into concrete the other day and it flew with vibration after that. But I discovered that I dinged the leading edge of one blade in two locations on the underside, and after I used a heavy metal spoon to smooth out the airfoil's plastic edge, all went back to smooth again. I don't think it is quite as much fun fighting the wind as it is flying in the gym, so I'll spend most of the time over the hardwood.
I've been trying to figure out how to fly a funnel (tail down) with this machine, as I think that close to the upper performance limit of fixed pitch technology. It certainly provides a challenge to it's pilot in coordinating all four control functions in a dynamic situation. Bailing out of unfavorable flight paths is also exciting as well.
I've been rotating counter-clock wise (viewed from the top), because the direction of flight will allow pushing forward to pull out of it better than it would if I rotated the other direction. At least I think this makes the advancing blade the one over the tail boom, so it should push forward better. If I went clock-wise, then it would be easy to get too vertical of a cone, and the rotor may not have enough excess lift to keep it flying. I think this direction would be a death spiral each time.
I've been trying to figure out how to fly a funnel (tail down) with this machine, as I think that close to the upper performance limit of fixed pitch technology. It certainly provides a challenge to it's pilot in coordinating all four control functions in a dynamic situation. Bailing out of unfavorable flight paths is also exciting as well.
I've been rotating counter-clock wise (viewed from the top), because the direction of flight will allow pushing forward to pull out of it better than it would if I rotated the other direction. At least I think this makes the advancing blade the one over the tail boom, so it should push forward better. If I went clock-wise, then it would be easy to get too vertical of a cone, and the rotor may not have enough excess lift to keep it flying. I think this direction would be a death spiral each time.
02-17-2011, 05:46 PM
#9
RE: Trials and tribulations of my SR120
Well the flight meter hit 75 yesterday. Just short of 7 hours now. Today though I am in withdraw, because the 5 in 1 board quit working yesterday. I started losing control of the tail rotor, though looking back, it has had problems from the first flights - I just didn't realize what the problem was then.
Early on, it would make a funny sound and have a slight glitch in the yaw axis every once in a while. I knowing nothing about these things and never seeing another 120 just assumed that was normal. But yesterday, it started to drift more until full rudder could no longer hold it. Yet the tail rotor seemed to operate when I tested it. So I thought the rotor motor was going south, but it seemed to turn fine when I blew on it.
I did figure out that it is easy to test the gyro however. Just hold the machine's skids and throttle up to about 1/2 power. When you rotate the helo around the yaw axis without touching the transmitter, one direction will speed up the tail rotor, the other direction it will slow down. What mine would do however is run at the right speed, then slow down and slowly build speed again. Sounds like a car shifting gears and accelerating.
Anyway Horizon stands behind their products, and a new 5 in 1 is on it's way.
I'm starting to understand why some people have two of these. I was really starting to get the feel of how to lead the controls the last couple of sessions to go where I want in forward flight.
Early on, it would make a funny sound and have a slight glitch in the yaw axis every once in a while. I knowing nothing about these things and never seeing another 120 just assumed that was normal. But yesterday, it started to drift more until full rudder could no longer hold it. Yet the tail rotor seemed to operate when I tested it. So I thought the rotor motor was going south, but it seemed to turn fine when I blew on it.
I did figure out that it is easy to test the gyro however. Just hold the machine's skids and throttle up to about 1/2 power. When you rotate the helo around the yaw axis without touching the transmitter, one direction will speed up the tail rotor, the other direction it will slow down. What mine would do however is run at the right speed, then slow down and slowly build speed again. Sounds like a car shifting gears and accelerating.
Anyway Horizon stands behind their products, and a new 5 in 1 is on it's way.
I'm starting to understand why some people have two of these. I was really starting to get the feel of how to lead the controls the last couple of sessions to go where I want in forward flight.
