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Old Apr 03, 2011, 10:32 AM
Master of Creative Crashing
United States, MI, Berrien Springs
Joined Mar 2011
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Drift in Phoenix

I know, this is going to sound like Iím overly impatient and need more practice. While thatís entirely true, I think Iíll ask my question anyway.

When hovering the Trex 500 in Phoenix, there is a strong tendency to drift left. Iím not talking about the left drift on takeoff. This is after a stable hover is established at a couple feet. When I take my hands off the stick, it accelerates left rather rapidly. The ďgentle nudgesĒ that are supposed to be used to maintain a stable hover donít seem to do muchóonly a stronger right stick to brake the left drift, then a slight left stick to keep it in place. And the pendulum beginsÖ

CaptJac wants me to start working on simple forward flight exercises, but that requires a reasonably stable hover to begin with. While attempting to hover, I can stay within the 10m box indefinitely without crashing, but Iím all over the place, mostly as a result of trying to compensate for the left drift. The goal of a stable hover isnít even a dream; itís more like a fantasy.

I tried adding some right trim on the DX6i. That seems to slow down the drift progressively through the first four notches. Then there seems to be a large difference between four and fiveówhen right trim is set at five notches, the heli basically falls over to the right and crashes. Should trim even be necessary in Phoenix?

Iíve never flown a real 500, so for all I know this is typical behavior. Is it? If not, what am I doing wrong in Phoenix? Other than being impatient, that is. And needing a few more eons of practice.

In the meantime, practice, practice, practice. And when I get frustrated with Phoenix (or, more honestly, with my performance on Phoenix), I can always retire to the living room and fire up the mSR. A few batteries worth of rock-solid hovering does my ego goodóeven if itís not a 500.
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Old Apr 03, 2011, 11:53 AM
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United Kingdom, England, Witham
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are you using the latest version of Phoenix? The trex500 did that to me as well (Using a Hitec Laser 6 as controller) so I used a different model (Vibe I think it was) but the problem went away with the last update
Also make sure you are using the sport and not the 3d one
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Old Apr 03, 2011, 12:21 PM
Master of Creative Crashing
United States, MI, Berrien Springs
Joined Mar 2011
47 Posts
Quote:
Originally Posted by Essex2visuvesi View Post
are you using the latest version of Phoenix? The trex500 did that to me as well (Using a Hitec Laser 6 as controller) so I used a different model (Vibe I think it was) but the problem went away with the last update
Also make sure you are using the sport and not the 3d one
Yes, I'm using the latest version (3.0.r), with all the latest model updates. And yes, I'm using the Sport, not the 3D.

I tried a few other models, including other 500s, a couple of 450s and a 600, all with varying degrees of success (or, in my case, lack thereof). Maybe it's time I admit, however reluctantly, that I'm just a slower learner than I'd like to think?

After re-reading the closing comment of my original post (about relaxing with my mSR), just for grins I loaded the mSR into Phoenix to see if it was any harder than the real thing. Just the opposite. Once the mSR is in the air in Phoenix, you can take your hands off the controls and it will hover motionlessly indefinitely. It certainly doesn't work that way in my living room. (Maybe I should turn the ceiling fan off...)
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Old Apr 03, 2011, 08:24 PM
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Not trying to hold the heli level are you? In a stable hover it leans to the right just a bit.

If it drifts to the left, you simply don't have it at the right angle for a stable hover. If it ROLLS to the left, then your trim is off or you need to calibrate the radio. Trim should not be needed on the simulator, for helis anyway - I find that the trim on the planes is sometimes off.
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Old Apr 03, 2011, 10:00 PM
Master of Creative Crashing
United States, MI, Berrien Springs
Joined Mar 2011
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Quote:
Originally Posted by jasmine2501 View Post
Not trying to hold the heli level are you? In a stable hover it leans to the right just a bit.

If it drifts to the left, you simply don't have it at the right angle for a stable hover. If it ROLLS to the left, then your trim is off or you need to calibrate the radio. Trim should not be needed on the simulator, for helis anyway - I find that the trim on the planes is sometimes off.
No, I'm not trying to hold it level. In fact, I'm not paying much attention to orientation, I'm just trying to keep it in one place. I hadn't thought about the distinction between drifting and rolling. It is in fact drifting, not rolling.

So I can't blame the trim, or the sim, or the radio. Which means, I guess, that I just suck at this. That's okay--it's nothing that can't be cured by a little time and practice (okay, a lot of time and practice). Hmmm... Required to spend a lot of time doing something I love that is just plain fun. Poor me.
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Old Apr 04, 2011, 10:57 AM
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Joined Mar 2010
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You canít forget the 3 P's of learning...

Practice, Practice, Practice!

Donít be like my stepfather, blaming all sorts of mechanical problems for his lack of hovering ability. Do (at least) 1 hr a night, practice in a structured manner (for now, just learn to hover!) and keep at it, persistence is key... then you will see the world of helis just open up for you, you will start enjoying flying even more and we will all be happy.

Good luck,

Igor
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Old Apr 04, 2011, 11:20 AM
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^^^^^ +1 ^^^^^^

The sim is boring b o r i n g.


BUT you would not find me at the field thinking hmnnn today I will try backwards inverted flight into a tick tock followed by cutting the grass! With out first doing it 100 times in the sim.

Hovering in the sim is really hard when I first got it I thought it was broken! But again you get used to it and before long it actually starts to make sense. Learn to fly this way and save yourself a lot of money.

The sim never gets exciting but it becomes a really good training aid whatever your level.

P
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Old Apr 04, 2011, 11:26 AM
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Originally Posted by hedgeheli View Post
Hovering in the sim is really hard when I first got it I thought it was broken!
P

Hmmm, I'm coming to similar conclusions now
Going to have to get a sim sorted out but that also means buying a good radio set too (ouch ! ) as the one's I have were all RTF packages most are 4 channel one is a 6 channel but I've no idea if it'll work with Phoenix

Getting really fed up with 10 min practice followed by 1 week down time waiting for parts
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Old Apr 04, 2011, 11:33 AM
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Did the setup come with a USB lead?
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Old Apr 04, 2011, 12:26 PM
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If the simulator is boring, you are doing it wrong...
http://jazzyflight.blogspot.com/2011...is-boring.html
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Old Apr 04, 2011, 08:02 PM
Master of Creative Crashing
United States, MI, Berrien Springs
Joined Mar 2011
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Quote:
Originally Posted by hedgeheli View Post
Learn to fly this way and save yourself a lot of money.
I couldn't agree more. Crashing in a simulator is cheap:
  1. I don't have to mortgage the house to pay the repair bills.
  2. I don't have to wait two or three weeks for the parts to come from Hong Kong.
  3. I don't have to wait two or three months for the parts to get back in stock.
  4. I don't have to take out a second mortgage on the house when I get tired of waiting and pay for express shipping.

Though I have to agree with Jasmine that the simulator is not boring, even at my level of ineptitude. I have three helis in various stages of assembly, and while I'm really looking forward to flying them, I'm not particularly looking forward to breaking them. I'm in no hurry--I can afford the simulator time, and besides, it's fun too. At my current level of expertise, if I were to fly the real thing, I'd be two minutes flying, three weeks downtime. I'd much rather spend some quality time each day, until I can have some small chance of flying for real without death and mayhem.

Back to the original subject, though--left drift. When I'm hovering (or what passes for hovering in my case), I never, ever give any left stick, only right. Is that really how it works?

By the way, Jasmine, I've been meaning to mention that I love your hairdo. The ears are a really cute touch, too.
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Old Apr 04, 2011, 08:16 PM
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Possibly yeah... the heli might stabilize towards a level attitude and you would need to lean it to the right again - but if it's properly trimmed, this shouldn't happen too quickly. Helicopters require constant management, and if you find that you're constantly putting in the same stick movement, then either you're flying in wind, or your heli is out of trim. Hovering movements should be fairly random, not always in the same direction. But it's possible that you're just waiting too long - you're slow on the draw, and by the time you notice anything, it's always the same thing. Hard to explain... just work on it. Hovering is a precision maneuver, and it's actually a little harder than flying around, but you need to learn it first and get comfortable with it because it's how you begin and end every flight, and how you recover in flight too - it's one of the stable attitudes, and you need to know how to achieve those.

Yeah those ears are freekin huge...
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Old Apr 04, 2011, 08:24 PM
Master of Creative Crashing
United States, MI, Berrien Springs
Joined Mar 2011
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Hmmm. Random it's not. If I take my hands off the controls during a stable hover, it immediately drifts left, never right. As I mentioned before, I tried setting the trim, and up to four clicks slowed it down, but the drift is still always left. After the fifth click on right trim, the heli just rolls right and crashes. I'm not sure why there's just a large difference between four and five clicks.

I don't mean to get personal, Jasmine, but you need a shave. Or at least a clip. Like the sweater, though.
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Old Apr 04, 2011, 08:30 PM
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hehe... check out this video of hovering in the simulator - it's a different sim, but it should work just fine.

Helicopter Flight Training Lesson 1 (9 min 51 sec)


You're using Phoenix... record your flight and post the file on here and I'll see if I notice anything. Perhaps your radio isn't calibrated or set up properly.
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Old Apr 08, 2011, 10:29 AM
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Of course, left drift is completely normal if everything is zero-zero, like it probably is on a sim!

Think about it---Physics alert!!!.

The rotor is horizontal, and providing pure vertical thrust. However the turning rotor blades make a torque around the main shaft (vertical).

The counteract this torque which would rotate the heli to the left, a small tail rotor is provided. It is blowing air to the right, pushing the tail to the left, and if it is adjusted perfectly, this left force, multiplied by the lever arm will counteract the torque of the main, giving zero net torque and the heli won't rotate.

This is where you are right now, everything great, right!

Well no. If you notice, the Main blade force in the vertical direction is just balanced to zero by gravity--if the heli isn't rising or falling, the torques are balanced so the heli isn't rotating, BUT the left force from the tail rotor has no balancing opposite force. Since F=ma, the heli will begin to accelerate to the left, because the tail is pushing it that way!

To compensate, you have to add a touch of right aileron. This tilts the main rotor to the right, and generates a small component of force to offset the tail rotor. As a minor point, you have to give the main a bit more power, since you lost a little vertical thrust in the tilt.

You can do this by hand, or you can trim a little right aileron. Or in Phoenix you can dial down the left drift via the setup window! My impression was that the left drift was a bit excessive in Phoenix, unlike a real heli.

So uncompensated left drift is normal, the exact amount depending on how you setup your pitch and rpm curves on the heli which determine how much thrust the tail needs to provide for torque compensation.

Physics Alert off.
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