General Links too long?

H

hrjrkr

New Member
Hi. I'm building an Align 500E. This is my 3rd heli build and it's being a pain. It seems that the links going from the servos to the swash plate might be too long. I have checked them 4 times and they
are the correct length. Following Tony's build video when I get to small links that need to be adjusted for the washout arms to be level, the links are bottomed out and I can't get the arms to level. Should the swash plate hit main rotor housing with full pitch? Should I just shorten the links from the servos to the swash plate?
Thanks
Joe
 
Lee

Lee

Well-Known Member
If the swash is hitting the main rotor housing at full pitch, its too high.
If you can take a pic and post it, that would make things easier to be 100% sure.
 
murankar

murankar

Staff member
When doing your setup for 90° are you using mid stick in IU1? If your links are to long then nothing will be at 90° at mid stick. Also the manual is more of a starting point. Most of the time you will need to make some adjustments.

Sent from my LG-E980 using Forum Runner
 
stokke

stokke

Well-Known Member
The geometry on those arms doesn't look quite right. I would move the Pitch and Aileron links at least one hole in on the servo arms. I can't judge the Elevator link by the picture, but the optimal geometry is usually achieved with the links pointing as vertical as possible from the swash down.

Judging by the picture, if you do correct your geometry issue, your drivers will come out of alignment. In my opinion your links are too long (as you suspected).

Are the links as short as they can be?
 
murankar

murankar

Staff member
That might be 2 holes in. Let the links dangle and see where the rest. Then move the linkage ball.

Make sure your linkage ball has the right distance to the center of the output shaft of the servo.

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Lee

Lee

Well-Known Member
I may be wrong, but from the picture, the geometry of the servo to swash arms looks odd.
Are you sure the servo arms are the correct length?
The manual says 19.5mm for the servo arms, centre drive shaft to centre ball link.
And 50mm from centre link to centre link on the servo to swash arms.
These are approx, and can be adjusted.
If the wash out block is hitting the main head block, then you can shorten these arms, or come in a hole on the servo arm to reduce the travel.
At low stick, does the swash get anywhere near touching the top bearing block?
 
H

hrjrkr

New Member
murankar I'm not sure what you mean by IU1 but yes I did have the stick at mid throttle.
stokke, no the links are not as short as they can be but I did follow the manual and yes I know you have to do some adjustments but it just doesn't seem right.
I know what you mean by the links being vertical to the swash but if you look at the pic the link ball on the swash is actually
more forward than the ball link on the servo arm. I will shorten the servo links and see what happens.
Thanks
Joe
 
H

hrjrkr

New Member
The servo arm ball is exactly 19.5mm to the shaft of the servo. The servo to swash plate links were 50mm but I had to reduce them so the swash would not hit the main rotor housing.
I will adjust the rest of the links and see what happens.
Thanks for all your help.
Joe
 
murankar

murankar

Staff member
Your setup should be done with IU1 provided you have the pitch curve setup right. Your pitch curve for IU1 should be 0 25 50 75 100. That way when you are at mid stick your pitch should be at 0°. Then everything is setup from the swash up. Level swash, level mix arms, then level flybar cage then zero out the blade grips. If everything is done right blade tracking should be spot on. Then test hover in normal flight mode.

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Graham Lawrie

Graham Lawrie

Well-Known Member
lee said:
i may be wrong, but from the picture, the geometry of the servo to swash arms looks odd.
Are you sure the servo arms are the correct length?
The manual says 19.5mm for the servo arms, centre drive shaft to centre ball link.
And 50mm from centre link to centre link on the servo to swash arms.
These are approx, and can be adjusted.
If the wash out block is hitting the main head block, then you can shorten these arms, or come in a hole on the servo arm to reduce the travel.
At low stick, does the swash get anywhere near touching the top bearing block?
Click to expand...

tthe link size for this is 47mm centre to centre of the ball links(hole to hole) metal rods should be 31mm and when ends fitted only 18mm of rod from end to end:)
 
H

hrjrkr

New Member
Wow Graham after making the servo links short enough so it would not bind at the top that is exactly what I have now 47mm (even though the manual says 50mm) and
the metal rod is 18 mm. Have not had time to do the other links but thanks to all for helping.
Joe
 
H

hrjrkr

New Member
It started to look good there for a while but when I went to adjust the high, low, cyclic and elevator pitch it was all over the place. Don't know if its my pitch gauge or the setup but I was getting all kinds of weird readings. I'm going to have to put this one aside for a while. Looks like I'm going to have to tear it down and start over.
 
murankar

murankar

Staff member
If you are not getting consistent readings then your gauge needs to be looked at or your work surface is not consistent. If your have inaccuracies with in a few tenths of degree you should be fine for a rough setup anything more than that I would investigate what causing the inaccuracy of the setup.

If you are using your phone as a gauge I would consider something else. I tried the phone and it was a pita to get things close let alone dialed in.

Sent from my LG-E980 using Forum Runner
 
H

hrjrkr

New Member
Work surface is a piece of 1/2" tempered glass roughly 30" x 30" and it is level. I am using the Align AP800 Digital Pitch Gauge. I will have to check the gauge. The readings (specially when checking cyclic and aileron pitch) were off 2 to 3 degrees.
It's kind of frustrating because I used a digital caliper and tripled check the links. That is why I set it off to the side and I will get back to at a later time. I'm not giving up just taking a break. I'm actually thinking of upgrading it to DFC
but just wanted to learn more about helis with the flybared version.
I have my 450 I can use. Thanks for all your help.
 
murankar

murankar

Staff member
I built a table deal that I can use to adjust level. All i did was use a piece of scrap wood and installed three adjustable feet. Now I can use the part of my digital pitch gauge that reads absolute level and level the platform. Once I have that level then I can go about leveling everything else.


When you zero the level it has to be leveled at the same point and orientation every time. When taking readings you the same orientation on the blades.

I tried using the tarot version of your level and did not like it much. I feel it left to much room for error. When I used it I used the boom for reference and as long as the frame did not move I was okay. Now that I have my current setup i like it more, I have the freedom to use the Solo method without the solo tool. I was able to get the main shaft perfectly vertical by twisting the bolts to the feet.

Even though you are using glass the surface it rests on needs to be dead on also. One more reason to have a leveling surface.

Sent from my LG-E980 using Forum Runner
 
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H

hrjrkr

New Member
Yes stokke the swash was leveled with a swash leveler.
Yes murankar I leveled the glass with a 4 foot level.
Maybe it's my age. I should probably take up crocheting.
 
D.O.G.

D.O.G.

Goblin 380 Supporter
Hey hrjrkr just a suggestion, have you looked inside of your servo arms to see if any teeth are missing? Just a thought.
 
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