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Can't Lift Off

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Old 05-29-2006, 07:43 AM
  #1
Battoo
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Default Can't Lift Off

Hi all,

No matter what i try i can't get my hirobo shuttle to lift off vertically. i have set all the trims but it still won't take off vertically. If i set the trims in the opposite direction that its trying to take off by one increment it trys to take off in the other direction. What am i doing wrong... Does the wind speed have an effect on the heli and if so what is the highest wind speed reccomended to hover and or learn to fly. Also some of the linkages to the main rotor and stabiliser seem loose to touch.. Is this normal.

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Old 05-29-2006, 09:03 AM
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Zik
 
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Default RE: Can't Lift Off

[edit]Nevermind, i had the wrong interpretation of the question.
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Old 05-29-2006, 09:03 AM
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Default RE: Can't Lift Off

heli's normally slide left upon takeoff to counter tail rotor forces. also in a stable hover, helis with tail rotors always lean slightly to the right (unless your main rotor rotates CCW from the top, then the heli would lean left in stable hover).

wind above 5mph, or gusty winds are generally too much for learning to hover. a gust of wind will make the heli shoot upward and in the direction of the wind. with well trimmed helis, you get almost pure vertical movement due to wind regardless of direction.

it's ok for the links to feel "free", as long as they're not on the verge of falling off under centrifugal forces & vibration. of course if the links are so sloppy that the pitch can move more than a couple of degrees, you might want to replace them to stabilize the heli. test this by holding the flybar still and rotating the blade grips back & forth to observe how much movement you get.
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Old 05-29-2006, 11:17 AM
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Battoo
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Default RE: Can't Lift Off

Thanks for your input

The linkages are not badly loose, just loose to touch so i think they will be ok!

I tried to fly again today with no wind but still it won't lift off vertically.

I have ballanced and tracked the rotors, I have made sure the tail stabiliser is secured and tight but i can't stop a big vibration that occurs when the throttle is halfway between idle and hover speed what is this and how can i stop it and will this cause the heli to NOT take off vertically?
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Old 05-29-2006, 05:13 PM
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credence
 
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Default RE: Can't Lift Off

The helicopter won't take off completely vertical and hover by it's self. You need to fly it. It doesn't matter how well it's trimmed. It will not hover by it's self for any extended period of time. That's simply the way helicopters are. Using the trims you can counter the effects of tail thrust, but you can't get rid of it completely because the thrust will always be there, and as air currents and density changes, so will the movement of your helicopter.


Basically, keep practicing, you'll get it .
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Old 05-29-2006, 06:56 PM
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Default RE: Can't Lift Off

it is possible to take off vertically, but it must be done quickly and smoothly until you're out of ground effect. it takes some practice to get down, but don't expect perfect "news chopper" style takeoffs until you've mastered hovering.

the way you describe it, the vibration may not stop the heli from taking off vertically. you should still try to fix it as it indicates something is amiss, which will likely affect stability. i'd start by checking the tightness of the blade grips. then if it still vibrates, check the main blade CG's.

if it still does it, check all your control linkages carefully for binding/slop. i know you said the ball links were good, but check the rest of it out anyways. it may help to bring it to an r/c guru friend or lhs so they can help you with the mechanicals.

edit: i know what credence means by having to fly a heli, they are always a handful for beginners. however you should *always* ensure your heli is setup as precisely as possible first. having your "best ever" setup every time you fly will make all the difference in the confidence you have with your piloting abilities. old addage goes: "You shouldn't have to fly your heli. Your heli should want to fly itself." it has worked for me since my first heli crash.
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Old 05-30-2006, 09:26 AM
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Default RE: Can't Lift Off

My helicopter has the similar problem for the past week. I just notice something wrong with the flybar blades last night. The blades are not at 0 degree in the initial state (everything center). One blade was at 10 degree and the other at -30 degree. I set them all back to 0 degree and it can take off vertical now. I think I bump the flybar once when the helicopter landed sideway once to cause this problem. Have you check your flybar blade angle?

DC
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Old 05-30-2006, 01:20 PM
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CVN-71
 
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Default RE: Can't Lift Off

Have you got your pitch set up correctly on the main blades? -9,-7,0,+7,+9 Is a good starting point..
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Old 05-30-2006, 11:46 PM
  #9
dannoh40
 
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Default RE: Can't Lift Off

I agree with the last post. I thought I got ripped 0ff because my heli wouldn't lift-off.
Both blades were out of pitch, one more then the other. I even bought a new battery thinking that would help(not)
Changed the pitch and up she went.

Dannoh40 & his fly right boys
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Old 05-31-2006, 02:52 AM
  #10
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Default RE: Can't Lift Off

Hi,

Here is whast I did when I had this vibration problem at BELOW hover throttle... Adjust the LOW END needle "slightly" OUT. This happens because of the MAin needle and the Low end needle are slightly off with respect to each other.

Secondly, -9 to 0 to +9 is too much for a beginner. That seems like 3D to me.

Falconeer.
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Old 06-03-2006, 03:13 AM
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Default RE: Can't Lift Off

Hi,

Thanks for all your suggestions, all of wich were very helpfull in letting me understand my heli. I did everything as you all say, i start her up, set her spinning and try to hover. I get her in the air and hover for about 10 seconds then i crash it into the fence (doh!) I now require a new set of rotor blades, a new swash plate and a few linkages. [:@]
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