General 450 Pro 3GX V2 tilting left on spool up?

Graham Lawrie

Graham Lawrie

Well-Known Member
I have started to get to the stage of my first take off, when i get to mid stick the heli looks as if it is going to tip over to the left so i spool down. I dont have training gear. What could cause this? how do i correct it? and if i continue to spool up will it tip over and destroy blade? HELP PLEASE:)
 
Your tail rotor creates thrust that pushes the helicopter left. You have to counter this with a little right cyclic, but not too much. This is perfectly normal.

I would strongly suggest getting a training gear or making one. Training gears saved my bacon on at least 20 occasions. Without a training gear, your helicopter very well could tip over and if the blades strike the ground, things will get messy.

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If you watch any video of a Trex hovering, you will notice that they are banked slightly to the right. This is the result of having to hold a little right-cyclic to counteract the tail thrust.

Probably not the best video, but since I am still a noob, you can see my delayed reaction during takeoff in this video of my Trex-250. Just jump to 1:50 in the video.
You will notice that the helicopter doesn't tip to the left because I am counteracting the tail with the right-cyclic. You will notice immediately after takeoff that the helicopter starts to slide to the left. I quickly counter this to hold it still in a hover, but this left-ward slide is an indication that I didn't give it enough right-cyclic while spooling up and taking off. You will also notice at about 2:17 as I am climbing that the helicopter is indeed banked to the right as I previously mentioned.

You will want to give a little more right cyclic than is needed to keep both skids on the ground. The key is to be very gentle in your inputs; you will barely be moving the stick. You can probably give it a bit more right cyclic until the left skid just comes off the ground if you want, and then you'll learn how much is too much.

Once you give a bit more collective and the helicopter gets light on the skids, it will probably try scooting to the left. If this is the case, give more right cyclic until the motion stops and you should be just about perfect for a hover. Tony's instructional videos go over scooting the heli on the ground, but you need a training gear for that.
 
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Thanks Zenmetu, i watched a video that said dont toch right cyclic till you left the ground, but when i was practising on the Phoenix flight sim i always gave it a little nudge at the right momentto get it to lift off straight up
 
I think the reason that some people say not to touch the stick until you take off is because beginners tend to move the sticks way too much. Without a training gear, the helicopter will tip over pretty easily and this will cause a crash.

If you are quick with the collective, the helicopter will not have enough time to tip over to the left before you add right-cyclic after takeoff. Unfortunately you don't want to be quick with the collective as a beginner, slow and small is the way to do it.

I'd say that the safest way to do it is to add right cyclic to keep both skids on the ground and slowly raise collective. Once the heli starts to slide on the ground, add a little more right cyclic to make it stop moving. Adding a little more collective should get you into a very low hover and then you can take it from there. Just keep things low and slow at first.

Training gear will help a lot. I've seen people use two wooden dowels fastened to the bottom of the helicopter. The actual training gears are pretty cheap, as long as you have a hobby store near you.

Best of luck. Keep us posted on how you do.
 
Actually not touching the cyclic is on flybarless heli's with a 3 axis gyro. It messes up the gyro and you end up fighting the heli once it's in the air. Take a look at my maiden flight of the Align 450 Pro V2, I made that mistake and it almost cost me the heli on takeoff. However if you have a flybar, I ALWAYS give a touch of right cyclic on take off.

Make sure your swash is level. If you don't have the tool, take the whole head off of the main shaft, leaving the main shaft in the heli. Leave the swash on the heli and connected to the links. Put a zip tie on the shaft and cut it so it just misses the anti rotation bracket. You can get a very good and close idea of what you need to adjust to get a level swash. You should have the exact same gap (if your swash was like mine) or no gap if you have an older swash. Either way, it's a very cheap and effective way of checking your swash for level which is a MUST!

Hope this helps and I agree with the above, get some training gear.
 
All my helis are flybarless. I do give a touch of right cyclic on take off, but only as the heli is about to lift off. Never had any issues doing that. Maybe it been worked out now in the firmware, as that was a thing mentioned back when Flybarless was new.
100% get training gear. Itgives you tonnes of confidence and save you MUCHOS ££££££ I got to the stage of looping my hell before my training gear came off. And i always use to put them back on after a rebuild or on a new heli until i was sure everything was ok. Now i don't, cause i'm 100% happy with my flying and control.
Good luck Graham
 
Tony said:
Actually not touching the cyclic is on flybarless heli's with a 3 axis gyro. It messes up the gyro and you end up fighting the heli once it's in the air. Take a look at my maiden flight of the Align 450 Pro V2, I made that mistake and it almost cost me the heli on takeoff. However if you have a flybar, I ALWAYS give a touch of right cyclic on take off.

Make sure your swash is level. If you don't have the tool, take the whole head off of the main shaft, leaving the main shaft in the heli. Leave the swash on the heli and connected to the links. Put a zip tie on the shaft and cut it so it just misses the anti rotation bracket. You can get a very good and close idea of what you need to adjust to get a level swash. You should have the exact same gap (if your swash was like mine) or no gap if you have an older swash. Either way, it's a very cheap and effective way of checking your swash for level which is a MUST!

Hope this helps and I agree with the above, get some training gear.
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Thanks Tony, I built my heli watching your videos and using the manual. it is flybarless. Iam going to use my tx on the Phoenix and see how it reacts with the settings on the tx that i have, then i am going to go over everything once then try a test hover today, video to follow.
 
Remember that when connecting the battery, the bird should sit on the skids. Do NOT pick up the bird, connect the battery, then set it on the ground - this messes up the gyro and will result in unwanted behavior during take off. I have the same bird and mine takes off perfectly level to whatever it sat on during take off.

ps. Get a swash level tool.
 
Tony,

The problem with the gyro on the ground is actually pretty simple. The same thing happens with the tail gyro in heading hold mode. I think that the flybarless systems use heading hold instead of rate mode and that would explain the behavior.

Basically what happens is that you give the helicopter input, they gyro expects a response, but there is none because the helicopter is on the ground and not free to move. On a flybar bird, if you give right or left rudder while the heli is on the ground, you will notice that the blades stay pitched until you get the helicopter light enough on the skids to allow it to spin around to the "expected" heading.

Alternatively you can kick the gyro down to rate mode and then back to heading hold mode to "re-zero" it and reset the tail pitch. Sometimes when I am handling my helicopter before flight, the blades are pitched because I moved the helicopter. I am in the habit of quickly flipping the gyro to rate mode and back so that I don't have any "surprises" during spool up and take off.
 
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