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Old May 19, 2004, 11:21 AM
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terryk's Avatar
Manching, Germany
Joined Aug 2003
177 Posts
Newbie problems maintaining a constant altitude

Newbie problems maintaining a constant altitude

Is it just me or do others have this problem?

I thought I was getting hovering down pretty well until a friend came around with his Hummingbird FP (almost identical to mine) and I noticed him maintaining a steady altitude in hover as though the helli was hanging on an invisible string. Being the modest chap that he is he attributed his skill to many hours on the simulator. Well Iíve tried that too but as well as being mind numbingly boring, the sim (Picofly) doesnít seem to model the changes in altitude too well.

I suppose its all about anticipation and although Iím getting used to seeing it balloon when a gust comes through changes to tail rotor speed also have an effect. Less tail rotor power more main rotor power and climb and vice-versa. And what else should I be expecting?

Since fitting my like90 blades things do seem a little easier though, maybe with these the slope of the throttle to rotor speed curve is not so steep?

Iíd welcome any comments or advice

TerryK
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Old May 19, 2004, 11:54 AM
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Coventry
Joined May 2004
268 Posts
Firstly how long has your friend been flying? I have started to become good and preventing my pic from moving too far, but altitude it a bit harder, and it may well just be that he is good at seeing the signs, or feeling the change in the wind and prepares for what he thinks is going to happen. Nothing you can do about that but admire, and aim to be able to do that as soon as possible, but it's not everything being able to hold a rock steady hover.

The other thing is that with a different heli, he may have a different setup, modifications, etc, and so his heli is just more stable because of what he has done to it.

Flying outside is difficult though, I have just been outside, and you can never tell when there is going to be a gust and which was it is going to kick your heli.

My advice is to go into forward flight, and whoop him and flying circuits
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Old May 19, 2004, 11:55 AM
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EddieNewYork's Avatar
Los Angeles, CA
Joined Apr 2004
4,930 Posts
I'm having the same problems with you. I blame it on the heli's weight I'm using the heavy 750 NiMH, and also have a GY240, and when the heli starts to fall, I start increasing the throttle but, I always do it too soft and too late, cause I think if I do it vice versa it will fly into the ceiling, so I just let bounce of the ground a little But since I started taking my heli outdoors I try not to let it bounce anymore. I agree with the sim, the lift is really not applicable. I hoping practice will cure this yo yo effect Is your heli heavy too?
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Old May 19, 2004, 12:42 PM
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Coventry
Joined May 2004
268 Posts
I think that this problems is also to do with the motor. Where as with the cyclic you can almost instantaneously counter a movement with a bit/lot of cyclic, but the motors really aren't that powerful so it can be hard to increase power to maintain height. Also if you decrease speed to prevent the heli from going up, you will lower the head speed and lose control too.
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Old May 19, 2004, 04:02 PM
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Melbourne Australia
Joined May 2003
5,263 Posts
I think this is typical of fixed pitch helis. I am getting better at anticipating and you do need to work the throttle a lot more to keep constant hover. (esspecially outside)

did your friend tell you that he was managing the throttle or did he just set it and forget it ?

Your batteries will also play a part. The shorter lifed nimh's power curve will drop more suddenly, so as you hover you are losing the ability to supply the same amount of amps at any given throttle setting. The lipos are not only lighter, but have longer duration and a better power curve. They can supply the same amps for longer. This takes one factor out of the equation.

Eddie..i'm surprised that for all your mods and upgrades, you still haven't done the single most important one yet...ie going to lipos I know you're worried about them, but that's why I think you should get them...because you already respect the damage they can do if not treated correctly.
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Old May 19, 2004, 04:45 PM
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terryk's Avatar
Manching, Germany
Joined Aug 2003
177 Posts
Well having started on fixed wing and got used to a 3 posn throttle (idle, cruise, max) I'm just not paying enough attention to that control. Its good having someone else to compare with though, a little competition is pretty useful too.

Someone said get out and fly a bit! I have had the helli down to the park for a couple of sessions now to try a bit of forward flight and the way the thing climbs as soon as a bit of forward speed is acheived astonished me. But having scared myself I pushed on and just tried to fly it on the cyclic like it was a fixed wing (It felt really satisfying to see the helli flying around way above my head though, I felt like one of the big boys)

Finally getting out of hover made me notice a few more problem areas on the helli, one is that I needed to do a range check first. After the airborne range check I ended up with the Rx antenna hanging straight down. I have a GWS Rx and the technique of wrapping the aerial around a drinking straw, as described in various threads does not seem to suit this Rx. (As anyone out there tried this trick on 35MHz?)

I discovered I didn't have enough down elevator trim.

Slowing down out of forward flight and getting nicely back into a hover is trick that is eluding me.

Thanks for the comments guys,
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Old May 20, 2004, 07:52 AM
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Coventry
Joined May 2004
268 Posts
If you find that you don't have enough trim, you can always move the servo control arm further out along the servo arm, so that you get a greater throw.

I found exactly the same thing, I flew out in the park and in just a bit of wind I was having to move the stick from one extream to the other, and there was just not enough to get decent control
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Old May 20, 2004, 02:29 PM
micro mechanic
aerohawk1's Avatar
Oz, Kansas
Joined May 2004
2,303 Posts
One thing you might try if you haven't already...
If your throttle stick has a "ratchet" effect,take your TX apart and remove the ratcheting clip from that stick.Your throttle should be smooth to maintain hover.

Aerohawk1
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Old May 20, 2004, 02:42 PM
Spark antenna on my Tx !
eekflyer's Avatar
USA, PA, Pittsburgh
Joined Mar 1999
436 Posts
Like Ozzie and AeroHawk1 alluded, you'll learn to think ahead and anticipate the throttle changes necessary to maintain constant altitude with a FP heli. You need to know the capability of your heli as well. That way, you'll know how much time you'll need from a particular decent to punch the throttle to avoid bouncing on the ground given how much battery power is left. Loosening the ratchet spring clip in your Tx will help too so you're not bound by the clicks. Be aware of the wind on your face. When the breeze blows, there's a good chance your FP heli will go up and which way it might be taken. I learned on a CP and just can't break my CP habits on my Corona. Time for a CP HB !

EEK
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