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General RC Heli Discussion Discuss general topics on rotary wing aircraft, including construction, Servo's, Gryo's and Stabilizer discussions.
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Topic Review (Newest First)
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| 02-12-2011 08:50 PM | ||
| kev-o |
Re: TRex pitching up in forward flight Actually your pitch up problem is not really your flybar system you are probably using a 3d type blade which has a more inboard c/g which in fast forward flight will cause pitch up condition. That's why there are so many blades available for diff flying styles. Try a diff set of blades. |
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| 02-07-2011 09:06 PM | ||
| flycrazy = Darcy Creighton |
Re: TRex pitching up in forward flight I was thinking the same thing... pitching (ballooning) in FFF typically indicates an issue with the flybar system. I don't know how cold it is there, but on some of my helis, the ball links shrink outside and make the flybar stiff.... check for this if you're in a cold climate. If this is the case, buy a second set of linkages and ball links... ream them so they are very loose, when in the cold, they will shrink to the right size. In the summer, swap them for your current set. 
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| 02-07-2011 08:45 PM | ||
| rotormonkey13 |
Re: TRex pitching up in forward flight As I recall the stock dampers on a Trex 600 (I've never owned one myself) are fairly stiff. I'd say to aim for at least 1800 - 1850. I don't know what the gear ratio is on the align, but 75% is a little low on the curve. It's probably okay, but as a general rule, you should gear the heli so that you're at at least 80% on the throttle curve in all flight conditions. If that means a smaller pinion, then go smaller. It's generally hard on the ESC otherwise. Ideally for you should adjust your HS with gearing rather than the throttle curve, and aim to get the throttle curve at around 90 - 95% for maximum efficiency. |
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| 02-07-2011 08:37 PM | ||
| Rob |
Re: TRex pitching up in forward flight What should my head speed be on a 600 I think My throttle curve at a hover is 75% with athe stock 1600 kv motor with a 10tooth pinion. Im runing the stock dampeners and I have looked at CCPM interaction.I think the trim is ok as it will hover when to lift off. I did adjust my CG and realgined my paddels Ill try it tommorow night if I get home in time. Thanks for the sudgestion guys thay are helpful. |
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| 02-07-2011 07:56 PM | ||
| rotormonkey13 |
Re: TRex pitching up in forward flight 'fraid not. Translational lift means the heli gains additional lift when in forward flight (or when it has some airspeed vs when it has none). It means you'd have to adjust collective. Translational lift will not cause the heli to pitch up. I too have heard people say misaligned paddles will cause the heli to pitch up, but I don't understand that myself (feel free to educate me if anyone understands why it might have that effect). I would think it would cause extra drag, or a wobble, but pitching up? Doesn't make sense to me since they'll be off kilter throughout the entire rotation of the head. Now things that WILL cause the heli to pitch up: Bad trim Too hard dampening Super stiff blades (relates to dampening) CCPM interaction Too low of a headspeed Light paddles and low profile airfoil will accentuate it as well |
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| 02-07-2011 11:55 AM | ||
| Jeremy300 |
Re: TRex pitching up in forward flight Quote:
Pitching up in forward flight is almost always caused by misaligned paddles. Realign your paddles and double check your CG. |
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| 02-07-2011 06:33 AM | ||
| bensidus197217 |
Re: TRex pitching up in forward flight I guess I didn't give enough info! Where the balls screw into the swash plate,blade grips and other linkage arms is where I mean to check. Those are the places that can put stuff out of adjustment without being noticable, if you push and pull on them as you watch carefully you may notice movement. It doesn't take much but it will be enough to change your adjustments with each take off and landing. |
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| 02-07-2011 03:53 AM | ||
| Rob |
Re: TRex pitching up in forward flight All the ball links are new and not sloppy. as for balance it was a little tail heavy. Mabe that was the problem. it was weird that it would hover fine after lift off and then fly around and all of a sudden it seemed out of trim. Ill try it out tonight if it is still light out when i get home. thanks rob |
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| 02-06-2011 11:56 PM | ||
| bensidus197217 |
Re: TRex pitching up in forward flight Check all your servo balls and linkage make sure they are tight. Slightly loose linkage balls can be pulled in one direction in flight causing the flight characteristics to change in the air but not the ground. |
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| 02-06-2011 07:50 PM | ||
| chris p |
Re: TRex pitching up in forward flight is the heli ballanced good ? |
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