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HomeAircraftHelicopterBeginners Corner › Pitch Curves...What Happend?
05-04-2005 08:30 AM  13 years agoPost 21
darkfa8

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Brick, NJ - USA

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Mike,

I double checked my Tx Pitch Curve settings, and I don't know what's up, but I do have 85% in for top stick in HH. I'll have to double check that with the pitch gauge later after I get some sleep. Otherwise, I changed the rest of the points in HH to mirror my Normal curve.

One other point that I can think of has been the "touch" of Right Aileron for translating tendency... what should I do about this, anything? I could turn the ball link out a turn or two on the machine or do it in trim? As it is right now, all the trims (Ail, Elev, Rud) in the radio are centered, only have sub-trim on the collective servo since the arm I got on there doesn't center at 90* with 0-sub-trim (i'll fix that eventually), and the swash is flat/level as a board....

I haven't been able to fly the heli in dead air but hopefully over the next few days the wind will be more calm and I can see how well the heli sits in a hover and what trimming is needed.

After that, I gotta finish setting up the Co-Pilot.. then after that, it's back to work on hovering-Ts in different orientations. I'm hoping to get nose-in hover before the month is over.

- Dan Goldstein
Team Revolectrix

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05-04-2005 03:12 PM  13 years agoPost 22
MJWS

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Airdrie, AB - Canada

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You probably won't get the right amount cyclic in on the bench to get it dead on. We always end up trimming in the air any way.

However, correct procedure would be to trim it in the air. Bring it down and then set the linkage so you can recenter your trims. Bottom line is that if it only takes a couple clicks to trim it.... lots of us will fly it as is and not sweat changing the links a tiny bit. If it's way out.... you might as well get the links right.

Sounds like you're close.

Mike

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05-04-2005 06:31 PM  13 years agoPost 23
darkfa8

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Brick, NJ - USA

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lil mistake...
Mike,

I didn't realize it, but those numbers above are for my "SIM" heli settings =\

Anyway, I loaded up the "Hawk" model in the Tx, and also readjusted my 12* for top stick in HH. Here are the numbers we should be looking at:

Pitch Curve – Normal Flight Mode
Stick Position Current % Current Pitch
P5 75.5 9*
P4 69.5 5*
P3 50 0*
P2 43 Averaged
P1 36.5 -5*

Pitch Curve – Flight Mode 1
Stick Position Current % Current Pitch
P5 75.5 9*
P4 69.5 5*
P3 50 0*
P2 43 Averaged
P1 36.5 -5*

Pitch Curve – Flight Mode 2
Stick Position Current % Current Pitch
P5 75.5 9*
P4 69.5 5*
P3 50 0*
P2 36.5 -5*
P1 18 -9*

Pitch Curve – Auto/Throttle Hold
Stick Position Current % Current Pitch
P5 91.5 12*
P4 69.5 5*
P3 50 0*
P2 43 Averaged
P1 36.5 -5*

ATV Setup
Throttle 100% Low 100% High
Collective100% Full 100% Low
Rudder 100% Left 100% Right
Aileron 100% Left 100% Right
Elevator 90% Fore 90% Aft

Sub-Trim Setup (0 unless noted)
Throttle +66
Collective -32

Sorry for the confusion =\

- Dan Goldstein
Team Revolectrix

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05-04-2005 06:40 PM  13 years agoPost 24
fritzthecat

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Virginia Beach, VA

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You still do not have 100% at the top of the pitch curve and 0% at the bottom.
In Idle-up With 18% low and 75% high you are missing 43% (18%+25%) of your available servo travel. This makes the servos work harder with reduced torque and decreases control resolution.

At the bottom 0% should be -10 deg, at top 100% should be +10 deg. 50% should be 0 degrees. No need to have more pitch in throttle hold.

Fritz


'Send Money, Women and Guns!'

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05-04-2005 08:48 PM  13 years agoPost 25
MJWS

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Airdrie, AB - Canada

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Fritz, some people are NEVER satisfied. (He is right of course.) I let you off easy.

It is as simple as moving the ball in one (maybe two) holes on your collective servo. This would give you a little more torque and resolution.

It isn't uncommon to run a little more pitch in HOLD to try and eek out a little more hang time in an auto. It complicates things a little though. My ships are set dead center as Fritz suggested as well.

We'll hit the logic any way just for kicks.

Total pitch range we are looking for is 22 deg. -10 to +12. So mechanical center should be +1. (We'll ignore F3D for now) We'll use the shortest arm possible to give us this range and keep a sensible atv value around 100. But we will feel empowered to adjust the atv's slightly to normalize our curve. +-5% is fine.

So our endpoints and mechanics are now set such that on our pitch curve:

0% is -10
50% is +1
100% is +12

A little more math would show us that 4.5% is about 1 degree of pitch(100/22). Our goal is linear pitch response, 0deg at center stick in all modes. Except in hold where we will allow a little extra pitch.

Expert Mode: -10 to +10 All modes matched except last point on hold.
Pitch Curves (All Except Hold) 0, 22.5,45,67.5,90
Pitch Curve Hold 0,22.5,45,67.5,100

The downside is the last point on our hold curve is steeper and will have a slightly different feel for aerobatic autos, but we shouldn't be tagging that much pitch any way. And by that time we will be flying a 'centered' and matched config.

Beginner Mode:
-5 to +10 Normal 22.5, 33.5,45(0deg),67.5,90
-5 to +10 Idle1 (Same)
-10 to +10 Idle2 0,22.5,45,67.5,90
-5 to +12 Hold 22.5, 33.5,45,67.5,100

This will give you 0 at centerstick always. You have two 'soft' flight modes for gentle decents and a little extra pitch for the bottom of your auto's. It's way too complicated for me... but it will work fine and has some good points for a beginner.

The math will always be the same because by definition we are setting up the mechanics first.

On my r50. I can only get 23 degrees total. It is -11.5 to +11.5. I use a monster 180oz servo on collective with a slightly long arm for a little more speed so the atv's are 84/85 (slight cost to resolution... who cares?)

All curves all modes. 0,25,50,75,100. No subtrim anywhere. Occassionally I'll back off idle2 a degree 5,27.5,50,72.5,95.

Hey it's a book. Have a blast, and don't sweat it too much. Your bird will fly fine. We tweak on these things because it's fun.

Mike

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05-04-2005 08:59 PM  13 years agoPost 26
darkfa8

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Brick, NJ - USA

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ugh, Fritz.. more work

so, i should have this:

P5 100% 10*
P4 75% 5*
P3 50% 0*
P2 25% -5*
P1 0% -10*

& for HH, instead of 12* at the top I should just have 10*?

I have a feeling it's gonna be a long night... I just stuck the pitch guage back on the heli, and at half stick, it's not reading exactly 0* i don't think .. ugh

I'm gona ditch this pitch gauge.. guess it isn't doing it for me...

I'm gonna order that Robart Pitch Gauge and Fly-bar lock combo from Tower...

- Dan Goldstein
Team Revolectrix

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05-04-2005 10:01 PM  13 years agoPost 27
MJWS

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Airdrie, AB - Canada

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Yep. You'll get there. Just takes a little time.

I wouldn't sweat the pitch guage. But if you need an excuse to get a new one...

Check it as you go. You need to concentrate on getting the collective arm centered and then connected to your centered servo. Your guage will show you if the throws are even, even if there is a large offset. For the 30 you really only need 20degrees total, so use a small wheel or arm on collective and enjoy the torque and resolution. Then you are back to releveling everything and setting correct pitch.

Half hour tops

Mike

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05-05-2005 01:14 AM  13 years agoPost 28
darkfa8

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Brick, NJ - USA

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before i dig in on this again...

the ball on the collective servo is 10mm out from center (this is what is recommended for "Sport" flying by my manual), 12mm is noted if I want "3D"

I ordered the Robart gauge and flybar lock, it's range is only +/- 10*, I guess for this machine it's fine.

I really appreciate all this help.. I feel like this is heli-boot-camp between you two.. which is fine, just wish you all were closer or I could call...

I had centered the swash in it's physical range on the mainshaft and then set everything else off that for 0* at center stick with everything leveled and linkages/bell-cranks at 90*...

I do want to try and get the Collective servo closer to 90* at center with less or no sub-trim, I'll just have to try another few arms or just make my own out of a wheel....

if i wasn't so anal, and you guys weren't so far away, this wouldn't be so bad...

btw, I did fly it for a tank today because there was no wind, a rareity here.. and eh, going into power to get off the ground and into a hover it leaned forward a lot, need to put in more aft elevator to correct that and it had a slight tendency to want to drift to the right. Guess it doesn't matter since I'm redoing it all anyway.. but I just needed to get some flight time with the good weather, my hovering control is much improved too

- Dan Goldstein
Team Revolectrix

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05-05-2005 05:42 AM  13 years agoPost 29
darkfa8

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Brick, NJ - USA

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more updated...

here's what I've grilled my brain over tonight...

disconnected the collective servo pushrod, dialed out all the sub trim, junked the existing arm/ball (arm wasn't at 90* without sub-trim and the ball had a knick in it, arm was a #2 on the Futaba star)... picked out a #5 on a Futaba star and it was perfectly lined up at 90*, stuck a new ball on the 3rd outter hole. Ok, so at half stick, with 100-100 atv, 0 sub-trim, the collective servo is now at dead 90* up and down

onto the collective arm... i moved it to it's right-most extreme and made a mark on the frame where it stopped.. then moved to left extreme, marked there.. took a measurement with my calier, found the center, put the arm on center, then setup the pushrod to set right on the servo arm at half stick/90* and the collective arm at it's center travel point.

Now, at low stick the collective goes to it's low mechanical limit, at high stick the servo is about 10-12% (atv) below the mechanical limit of the collective arm

In my radio, top stick is at 100%, bottom 0% in the Pitch Curve for "3D" Idle-Up 2, at full stick, I get 11*, at low stick I'm getting -15*+, my gauge only goes to =/- 15* and it's a bit beyond that on the bottom end...

That is where I stopped with the collective system cause the Aileron servo wheel has been bothering me...

To end my setup frustration I ordered Gary Wright's 90* link-tool and swash deflection gauge.

My aileron servo wheel and it's setup isn't as exact as I wanted and for the time being I actually had to dial in some sub-trim in order to get the balls perpendicular to the main shaft.. they were off slightly =\ I also reset the lengths of the Aileron servo-to-bell crank push rods...

Guys... I am determined to get this dialed in... I feel like I'm missing something, or making some faulty adjustment, overlooking something.. I don't know.. but this is one hell of a crash course in perfecting the linkage geometry for this machine.. I can only hope other machines are easier.. or maybe I'll get better and this won't be such a fight

If either of you guys wants to or can call me tomorrow or when you have time, maybe I could better sort out some of this via the phone with the machine right in front of me: 609.384.4756, any time between 11am-10pm EST.. or, i'll call you

- Dan Goldstein
Team Revolectrix

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05-05-2005 06:01 PM  13 years agoPost 30
darkfa8

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Brick, NJ - USA

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Mike,

Thanks for the call to help me sort things out. I can sleep tonight knowing my bird is set as damn near perfect as sanely possible

Thank you to Fritz and Wayne as well. I think I'm figuring this stuff out

ok, i'm gonna go fly now... :P

- Dan Goldstein
Team Revolectrix

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HomeAircraftHelicopterBeginners Corner › Pitch Curves...What Happend?
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