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03-09-2010 07:00 PM  8 years agoPost 1
Damper

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Point Blank TX USA

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I need some ideas what could be wrong with a left cyclic input and the Heli rolls with a nose down corkscrew movement. It looks cool and everything but I am not giving that command when sraight left input in a stationary place. Is that normal for the Heli do a nose dive corkscrew manuever because the right input cyclic is a nice level roll from a stationary spot.

Full Throttle Spooning Leads To Forking

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03-09-2010 07:30 PM  8 years agoPost 2
rotormonkey

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Ottawa, ON - Canada

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Sounds like your phasing might be off. Which heli is this? If the phasing ring is adjustable, then you may be able to just twist it a little to fix the problem. Otherwise if it's a Trex or similar you'll be relegated to playing with programmable mixes in your radio to compensate.

If it can't hover, it ain't worth flying.

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03-09-2010 08:23 PM  8 years agoPost 3
hornet dave

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Cedar Rapids, IA USA

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I think it's time I put together a "how to setup your heli for 3D flight video" because these sorts of questions always come up.

So, the short version of it is:

your CG is off
resulting in your swashplate being crooked
causing bad left rolls.

Of course your phasing is off, too, because with your heli in such a botched-up state, you get good rolls to the right. If your phasing was correct, your rolls would be more or less equally screwed up both left and right.

Here's your fix:

1) adjust, trim, mix, twist, and/or whatever it takes to get your swashplate totally interaction free. (most helis don't even get this far in setup)

2) get your CG correct. First off, don't lift the heli by the flybar and say "hey it doesn't tilt much the CG must be good" because this method is WORTHLESS! You need to tilt your heli over sideways 90 degrees by grabbing the heli by the maingrips; this should put the body of the heli parallel to the ground. Move equipment or add weight until the heli sits level with the ground rather than having the nose or tail fall towards the ground. Do this with around half a tank of fuel. (now your heli is in the top 10% when it comes to setup)

3) get your heli trimmed; on a calm day trim the heli for an upright hover. Next, flip it upside down and check the trim in an inverted hover. If you have to hold in some cyclic while inverted but not upright, split the difference on the trims so you have to hold the cyclic a little one way while upright and a little in the other direction while inverted. This should be minimal if your swash is setup properly and your CG is on the mainshaft. (now your heli is top 5%)

4) Now adjust your phasing so the heli flips and rolls properly on axis. (congrats your heli is now in the first percentile in heli setup)

Most folks simply throw the heli together, take a WAG at leveling the swashplate, then fly the heli. Whichever heli they throw into the air in this manner that flies the best becomes their "favorite brand" or "the best heli on the market" or whatever when it's more a matter of dumb luck getting them closest to a good setup.

I got a fever! The only prescription is MORE 6HV

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03-09-2010 10:26 PM  8 years agoPost 4
holzback

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noblesville IN United States

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set up is key, you should have even elev and ailor deflection and the make sure the swash is perfectly level alll the way through the pitch range

you aint crashin you aint learnin

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03-09-2010 11:38 PM  8 years agoPost 5
Damper

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Point Blank TX USA

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Hornet dave

Point well taken. Thx

The phasing seems the point of interest to me. Excuse my ignorance on this, but I thought a Titan 50 phasing was essential bullet proof. Can it be phased in? If yes, how is it accomplished? Thx

Full Throttle Spooning Leads To Forking

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03-10-2010 12:06 AM  8 years agoPost 6
hornet dave

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Cedar Rapids, IA USA

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plastic headblock or the older style metal headblock?

If it's the plastic headblock, the only reasonable thing you can do is use a transmitter mix (ail -> elev and elev -> ail) to adjust the phasing.

If you have the older metal headblock with the adjustable phasing ring, just adjust the ring one way or the other very slightly until you get your heli reacting properly.

Different blades, paddles, and who knows what else all affect the phasing. That being said, a fixed factory position may be in the ballpark but will probably not be perfect.

The good news is you have a mechanical mix heli so you can forget all the hassles of a ccpm setup.

If you're into FAI style flying disregard everything I say because I think those guys go about setting up the heli in quite a different manner.

And congrats, simply going down this road will greatly increase your knowledge of how to get these helis to work well.

I got a fever! The only prescription is MORE 6HV

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03-10-2010 12:45 AM  8 years agoPost 7
Damper

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Point Blank TX USA

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I am sorry not being more specific on the rotor head. It is a Titan Se metal block head. Phasing ring is what exactly? I am guessing the two metal legs that go into the metal slider. Is that correct?

Full Throttle Spooning Leads To Forking

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03-10-2010 12:58 AM  8 years agoPost 8
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

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Is that correct?
That is correct.

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

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03-10-2010 01:44 AM  8 years agoPost 9
Damper

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Point Blank TX USA

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So how is that adjustable? By turning clockwise or counterclockwise to phase in the flybar?

Full Throttle Spooning Leads To Forking

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03-10-2010 02:01 AM  8 years agoPost 10
hornet dave

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Cedar Rapids, IA USA

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hmm. the titan SE. isn't that the latest version with the two jesus bolts and the red anodized covers? if so, it's not adjustable.

I got a fever! The only prescription is MORE 6HV

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03-10-2010 02:10 AM  8 years agoPost 11
Shawn Behrens

rrApprentice

DEEP IN THE BOG

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While I agree that a good setup is a great foundation for learning. Please consider this.
Most people naturally give an unwanted down eleavator input with what they believe is a pure left cyclic input. If you don't believe me put your transimitter to the servo/channel monitor screen have have a friend watch the eleavator channel (now you look up into space)and try giving what you beleive is a pure left cyclic input. You might be surprised. The good news the fix is easy. Lotsa fuel.
shawn

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03-10-2010 02:15 AM  8 years agoPost 12
thorpdrvr

rrApprentice

san antonio, tx

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If it doesn't do it to the right you may be inadvertantly putting in some elevator on the aileron input without realizing it. Try putting in a whole bunch of expo on the elevator channel for one flight and try a few rolls to see if its you or the heli.

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03-10-2010 02:29 AM  8 years agoPost 13
Damper

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Point Blank TX USA

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Hornet dave

Yes, I guess I will retrace the cg as you described. Thx dave

Thorpdrvr I kinda eliminated that but I did not look at the servo input on the radio itself. I did by concentrating giving up elevator and down elevator on the diagonal on the sticks while flying several occasions with same results but that is based if my inputs actually did that. Not postive on that, so I will do that way to make sure. Thx

Full Throttle Spooning Leads To Forking

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03-10-2010 03:41 AM  8 years agoPost 14
rotormonkey

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Ottawa, ON - Canada

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I don't think the paddles will actually affect phasing at all. The big factor is the blades. Depending on the weight, the airfoil, etc ,etc the blades will tend to lead/lag more or less. The manufacturer can't account for every blade out there so most that have a fixed phasing ring just offset by a degree or two and call it close enough. Generally it is (for me anyway).

Anyway, ideally the way to fix it is mechanically by rotating the ring a degree or two at a time, and test flying. The ones I've seen with adjustable phasing use a set screw to fix the ring to the main shaft. You can back off the set screw, rotate the ring, and re-set the screw.

To get the phasing CLOSE on the bench you can line the blades up with the tail boom and give forward/back cyclic inputs. Doing so should ONLY move the flybar. The blades shouldn't change pitch at all. That gives you 0 degrees assuming the blades are centered in the grips. But because the blades lead/lag in flight 0 degrees isn't generally optimal which is why you need to test fly it.

If you don't have an adjustable phasing ring, as many helis don't, then programmable mixes are your only recourse.

Since I didn't actually read any of the above in a book anywhere, take it with a grain of salt. That's just how I do it and my understanding of it. Maybe it's wrong, but it makes sense to me.

If it can't hover, it ain't worth flying.

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03-10-2010 04:41 AM  8 years agoPost 15
Damper

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Point Blank TX USA

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Programing mixed in the radio I have not done and another good reason I do not understand it and how is there any example u can give me to understand the fundamentals of programable mixing ,rotormonkey? Thx

Full Throttle Spooning Leads To Forking

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03-10-2010 05:08 AM  8 years agoPost 16
rotormonkey

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Ottawa, ON - Canada

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The idea behind pmixes are that when an input is given on the "master" input, the "slave" will do something in proportion. That's probably not a great explanation, but I'm not really sure how to explain it. For example:

Suppose you're not using a governor. Your throttle curves are all set up right, and everything's fine except your heli bogs when you give full aileron input for a roll. You can't fix that with the throttle curve, so you'd use a mix. In this case, you want to increase throttle when you give an aileron command. That way, the motor outputs more power the more aileron you give. To do that you'd set up an aileron to throttle mix. Aileron being the "master" throttle being the "slave". Suppose you have a mix of 25%. That means that at full aileron deflection your throttle will increase by 25% of what it'd normally be. (at least that's how I understand it). And the response would be proportional everywhere in between. So at half aileron deflection you'd automatically increase throttle by 12.5%.

In the context of phasing, you'd want to set up two separate mixes. One would be elevator to aileron, and the other aileron to elevator. That way no matter what input you give on the cyclic, it'll be offset slightly in whatever direction to correct for the bad mechanical phasing.

I'm really not sure how else to describe it. Hope that makes sense...

After re-reading your original post, if rolls one way are fine, but not the other the problem is certainly not phasing. More likely it's just a problem with your thumbs

If it can't hover, it ain't worth flying.

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03-10-2010 05:24 AM  8 years agoPost 17
Spitfire1

rrElite Veteran

Perth Australia

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2) get your CG correct. First off, don't lift the heli by the flybar and say "hey it doesn't tilt much the CG must be good" because this method is WORTHLESS! You need to tilt your heli over sideways 90 degrees by grabbing the heli by the maingrips
After reading this Ive gone out and used this method on my heli, but what Im finding with my Trex 600e, is in order to get it to balance Im haveing to have the 6s 5000 hanging right out the front so far theres nothing supporting it at the bottom, meaning the pack can spring up and down, is this alright??

I dont have anything I can move forward, everyhtings already up front.

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03-10-2010 05:45 AM  8 years agoPost 18
Damper

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Point Blank TX USA

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It makes sense rotormonkey, believe it or not. I will apply what u said tomorrow and see it works. Not to monopolize your time I have dx7se I go to to the programable menu in the radio or is there a menu already defaulted for these applications?

Dumb thumbs is my bet too but I would like some knowledge on programming mixes though sounds fun to do and to learn, especially if it makes flying more enjoyable.

Full Throttle Spooning Leads To Forking

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03-10-2010 02:56 PM  8 years agoPost 19
budz

rrApprentice

las vegas

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spitfire1
you should do the CG test with the canopy on. otherwise, it's going to be slightly tail heavy

team solo

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03-12-2010 12:38 AM  8 years agoPost 20
Damper

rrVeteran

Point Blank TX USA

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I am blaming 90% on the operator and 5% on the loop interference with the main grip and remaining a slight bend on the ball screw of the loop connection on the bottom.

Full Throttle Spooning Leads To Forking

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