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CarbonXtreme . Midland Helicopters . HeliProz

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Century Hawk - Falcon - Raven - Predator > Raven 50 head setup.
 
 
rotormonkey
Senior Heliman
Location: Ottawa, ON - Canada

So I have this swanky new metal head and I'm having problems getting everything all squared away. I have two questions:

1: I have more aileron pitch in one direction than the other. Oldfart mentioned at the funfly that end point adjustments could be used to dial this out. The only problem is that if I do that, then ccpm interactions are introduced where I had none before.

For example, I adjust the high point of the pitch servo to lower a bit and/or the low point of the aileron servo to come up. Now I have equal pitch in both directions, but when I move the collective to high stick the swash is all cockeyed. I suppose I could use a pmix to dial it out, but I'm already using all my available mixes for other stuff.

2: I spent 3 hours trying to fix a problem that I don't believe is even a problem anymore. When I'm at full low stick, and I give full aileron say to the right the bell mixers bind up in the flybar cage on the right side when I have the blades parallel with the boom. But they only bind if the flybar is tilted to the left a little.

Now if I understand how everything works properly (and there's a good chance I don't), when in flight the flybar disc will tilt right when I give right cyclic, correct? If that's the case, the I don't think that binding would be a problem. So should I even worry about this?

Any input you good folks could give is well appreciated. Thanks guys!
08-16-2008 01:34 PM
 
 
Blade_Master1
Key Veteran
Location: Canada

 told you the metal heads weren't that good

Anyways sounds to me like you have aileron trim set to one side
is it centered ?

As for the binding Wasp says the stock bell mixers work well for this head although I haven't tried it. Having to much fun flying now with the stock head.
another thing to try is lower your pitch setting and or cyclic

Did you level swash at mid stick?
if your swash starts out level then gets cockeyed up top or at bottom use the travel limit and increase the travel on the servo

I'm sure your links are = on both sides of flybar
and the rotor links are =

maybe 1 of your servo horns are off center

JM2C's :)
08-16-2008 02:43 PM
 
 
Dilbeck
Key Veteran
Location: Springdale Arkansas

I have heard of some problems with this metal head, I also encountered some issues with binding and due to no instruction manual had to work out the problems on my own. Due to the variables in Hawk/Raven/eccpm/mccpm/servos/servo arm length exc, problems have to be worked out for each setup. If you use the Allen wrench method Ive described in previous post to level the swash you will locate the problems at high, mid and low collective. If you level the swash at mid stick on all 3 points and then find it out of level at full collective something is out of sink or off kilter in the setup. I'm a firm believer in no mixes of any kind if you can get away with it. I also believe if you work it out you will not need it and will get a level swash at all points.

If it doesn't fly sell it!
08-16-2008 03:24 PM
 
 
rotormonkey
Senior Heliman
Location: Ottawa, ON - Canada

Okay, I think there's a misunderstanding here. Currently my swash IS level at all points of collective travel. There are no interactions, links are the same length on both sides.

The problem is that I have more cyclic (aileron) to the left than I do to the right. We're off by about 2 degrees. When I asked oldfart about fixing that he said I should use EPAs to do so.

Now, I CAN fix it using EPA, however IF I do - THEN I get interactions because the high point on one servo has changed, but not on the other. Make sense? My question is - what is the proper procedure to fix having more cyclic one way or the other? I do not need help fixing interactions.

As for the binding, I don't think it's a problem as long as everything works the way I think it does in flight. If I give right cyclic, does the flybar disc tilt right? If so, then no problem?
08-16-2008 07:25 PM
 
 
Blade_Master1
Key Veteran
Location: Canada

Quote 
If I give right cyclic, does the flybar disc tilt right? If so, then no problem?

I was just flying when I give any cyclic the flybar stays pretty much parallel with the rotor disc


the only way I can see you having more travel on 1 side
is from centering your servo horns

did the horns fit perfectly or did you need sub trim to get them perfect?

JM2C's :)
08-16-2008 08:04 PM
 
 
the Wasp
rrProfessor
Location: Vt

Swash and Servo Setup (only),,

Swash Binding Problems

1) a servo problem

1a) bad servo

1b) wrong gears in 1 servo

1c) 1 servo mounted lower and or one servo mounted higher,, here, when a Servos moves the Linkage Angles change, if one servo is mounted slightly higher or lower it's Linkage Angle is different than the other, this could create the problem when the Servo Arms is at higher deflections

1d) 1 Servo Mounting Frame bent out more than the other, here too when the Servos move the Linkage Angles change, if one Servo Frame is bent out more it's Linkage Angle is steeper than the other, this could create the problem

1e) different servo arms, so you will have different Ball Hole placements

2) both Servo Arms are not set to "True Level"

3) Servo Subtrim,, 1 servo could be set way to high, here my Rule of Thumb is not to use more than 18%, BUT with my JR Equipment and the right Servo arms I wont need more than 6% Subtrim !!

4) different Linkage Lengths, here if you have different Linkage Lengths you will again get different Linkage Angles when the Servo Arm is at higher deflection

5) if you are using Hitec Servos they may need programming..


Servo/Swash Setup,,

1) first,, make sure your Servo Arms are 100% level, use less than 20% Subtrim,,

2) set both Aileron Linkage (servos to swash) to the same lengths,,
2a) mount linkages to heli (servo & swash)

3) now (at Mid Stick/50% Pitch Curve) set Swash Height so the Anti Rotation Pin is centered in the Anti Rotation Guide

4) now level Swash,, leveling the Swash is a balance between Servo mounting to high/to low and adjusting their Linkages,, to much of adjusting one or both can create the problem you have,,

now stop Swash CYCLIC Binding with Aileron Swash Mix or with Dual Rates (set both high rate and low rate the same)


now on what Old Fart said (Phil),,
now after you have got the Swash level and the Pin centered in the Anti Rotation Guide and you have set your Collective Pitch (about 11 degrees), if you get Swash Interaction at full Collective (using Collective ONLY) you can use the ATV's to stop this Collective Swash Interaction (as Phil said),,

you have now setup the Swash and have no Collective Interaction and NO Cyclic binding in the Swash,,,,,

Metal Mixers on the 30/50 head,,
(compared to the Predator's Grips) I believe the Arms on the 30/50 Metal Grips are farther out from the Spindle's Center, so to achieve the same pitch the 30/50 Mixers has-to travel farther than on the Predator, so on the 30/50 we get the binding with the Metal Mixers,, so just use the Plastic Bell Mixers on the 30/50s, they perform just as good..

Jim
Buzz Buzz Buzz
08-16-2008 10:47 PM
 
 
rotormonkey
Senior Heliman
Location: Ottawa, ON - Canada

Swash and servo setup:

1: No servo problems. Of this I am absolutely certain.
2: Just eyeballing it, they look pretty level to me. If they are 89 degrees instead of 90 to the mainshaft, I'm sure it can't cause too big a problem.
3: I've got 15% and 23% on the aileron and pitch servos (left and right ones). Yes I'm sure it could stand to be lower, but in order to get a straight run from the servo balls to the swash balls I'm limited to only the 3 longest servo arms that came with the servos. This is the best I could do with those arms.
4: Linkage lengths are symetrical on either side.
5: Indeed I am using hitec servos. Please explain "programming". First I've ever heard of programming a servo. Unless you mean playing with radio settings?

On to the next part. This is all rudimentary setup stuff. There is no binding in the swash itself. Binding is ONLY between the flybar cage and bell mixers, and ONLY when at full negative pitch giving full right or left on the right stick, and ONLY when you tilt the flybar in the opposite direction of the cyclic you're giving.

I suppose what oldfart was talking about was just getting rid of ccpm interactions. I would have thought I would have interactions with the subtrims not all being equal, but even with a bubble level on the flybar paddle I have none. You can't feel the paddle twist when moving the collective at all either. I haven't had a chance to flight test yet though.

The more I think about it, the more I'm sure that the subtrims not being equal is likely the culprit here. I'm just not sure how to correct it without CAUSING interactions. I did try playing with the end points to correct it, but after doing so I end up introducing CCPM interactions when there were none to begin with.

As for the plastic bell mixers, they are quite a bit shorter than the metal ones and I'm sure that using them would solve the binding problem. I'll use them if I have to, but I'm not convinced that that binding problem IS a problem. If the flybar stays level during flight no binding would ever occur. And plastic mixers on my shiny metal head would be an eyesore. If I can get away without 'em, I'd prefer to do that.

Back to subtrims and interactions.. Does what I'm saying make any sense? Is it possible to have unequal aileron throws w/o interactions? It doesn't particularly make sense to me, but I SWEAR this is what's happening.

I appreciate the suggestions guys. Please keep it coming!
08-17-2008 12:06 AM
 
 
the Wasp
rrProfessor
Location: Vt

""Indeed I am using hitec servos. Please explain "programming". First I've ever heard of programming a servo. Unless you mean playing with radio settings?""

yeeup,, Hitec makes a Programmer (see link),, I'm betting you need to program them, I have Hitec's Servos on 1 of my planes, nice servos but they needed programming, I have heard and read about having to program Hitec's Servos many times,,

find some Plane Guy in your club that has a Programmer and program your servos and start over,,

http://www.servocity.com/html/servo...mer_tester.html

Jim
Buzz Buzz Buzz
08-17-2008 12:22 AM
 
 
the Wasp
rrProfessor
Location: Vt

I see,,

""Binding is ONLY between the flybar cage and bell mixers, and ONLY when at full negative pitch giving full right or left on the right stick, and ONLY when you tilt the flybar in the opposite direction of the cyclic you're giving""

that will never happen in flight, I too asked this question to Steve H some 5 years ago,, it will never happen in flight !!


but program those servos, one may be traveling farther than the other !!

Jim
Buzz Buzz Buzz
08-17-2008 12:27 AM
 
 
rotormonkey
Senior Heliman
Location: Ottawa, ON - Canada

No kidding.. I had no idea those servos were programmable.

Not to be contradictory.. BUT... If the problem is that one servo is traveling further than another could I not just adjust them using EPA to get the same result? What will programming the servos do for me that my radio can't?

Also, if it were one servo traveling further than another, wouldn't I end up seeing CCPM interactions rather than just more cyclic one way than another?

Honestly, I'm not trying to say you're wrong, or contradict you in any way. I'm just struggling to understand and learn.
08-17-2008 03:30 AM
 
 
Blade_Master1
Key Veteran
Location: Canada

with the hitec servo programmer you could program the servo's so your radio has zero for sub trim then you would have equal travel on all servos


your sub trims not being equal or at least very close could explain the un-even travel

set up your servo's the same way for all 3, if the servo horn fits better at a positive angle make them all positive then adjust sub trim accordingly to bring them level
once the servo's are 90'd (centered) then level swash

JM2C's :)
08-17-2008 03:51 AM
 
 
the Wasp
rrProfessor
Location: Vt

yeea,,, what he said

Jim
Buzz Buzz Buzz
08-17-2008 04:21 AM
 
 
the Wasp
rrProfessor
Location: Vt

I'm sure someone in your club has a Programmer, if not maybe you local shop can do it for you..

Jim
Buzz Buzz Buzz
08-17-2008 04:24 AM
 
 
rotormonkey
Senior Heliman
Location: Ottawa, ON - Canada

Just throwing this out there... But say I put 15 points of subtrim in my radio to move the arm up, could I add 15 points of EPA to the bottom, and remove 15 from the top end and end up with a centered servo with equal throws (assuming the other was 0 subtrim)?

I'll ask around about the programmer, but I figured I'd ask if the above would work.
08-17-2008 05:18 AM
 
 
the Wasp
rrProfessor
Location: Vt

edited

Monkey,, as I have found with JR it does not work that way,,

15% Subtrim is not that much, besides that if you add 70 or 80% "Right" Subtrim it affects the Left side,, how, you wont have as much Servo Travel on the Left side,,

test it !!

raise your Subtrim around 80% (even higher) on one side, then move your stick side to side, you will see your Servo travels farther on the side you have the Subtrim adjusted for!!

Jim
Buzz Buzz Buzz
08-17-2008 05:51 AM
 
 
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Century Hawk - Falcon - Raven - Predator > Raven 50 head setup.
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