450 Problem with FB head!

[DAL2855]

Ok guys I am in the process of rebuilding my HK450GT with all Align parts and just got the new Align head installed and for some odd reason, after leveling the washout arms and upper set of arms with the Flybar cage, I am getting about 3 degrees of negative pitch. And I can't figure out why. I've remeasured all the links and they are all the correct length but for some reason, I'm getting a -3 degrees of blade pitch at the midstick and swashplate is level. What do I need to do here? Or should I even worry about it?

 

[Westy]

you need to raise your swash link (EQUALLY) about 3 turns and see how that works out. AS long as your servos are @ 90º at mid stick.

then recheck.

 

[DAL2855]

Yeah but if I do that Westy, then the washout arms will no longer be level and neither will the upper arms to the blade grips with the Flybar cage!

 

[Island Breeze]

is your pitch curve at linear setting's? 0-25-50-75-100. If so try going to your swash mix and bump it up until you get the 0 at mid stick, then check your + and - pitch. just FYI even if you measured the links you sometimes have to raise or lower them to get all arms level (mixer arms, cage etc.).

 

[Graham Lawrie]

Your pictures are not very clear on my phone. Someone on here had the same issue and not that long ago. I think it was in the 600 section. If I remember right it was arms the wrong way round.

 

[DAL2855]

Ok Graham, are the arms coming up supposed to lead the blade or lag the blade in timing?

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Right now I have them lagging the blades.

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What I am talking about here is the ball link on the inside end of the blade grip.

 

[Lee]

If everything else is level and even, then adjust the long links to the upper arms to get 0º pitch.

 

[DAL2855]

Yeah but when I do that, then the upper arms are not level with the flybar cage, that's my delima!

 

[Tony]

Watch my video that I posted in the other thread. YOu will 90 your servo arms, then level your washout arms, then your mixing arms, then get 0 at mid stick. Then check full positive and negative. IF you have to adjust the swash links, adjust them, level the washout arms, then the mixing arms then 0 at mid stick. You will keep doing this until everything is perfect. Your positive and negative should be within a half a degree.

 

[Derek]

yeah, I remember having Tony help me with my 500 on this issue. I had to go through each set of arms 3 or 4 times in order to get everything 90 degrees and level.

 

[DAL2855]

I guess what is really confusing me Tony, is this bird has the fixed links on Flybar cage and also from mixing arms to blade grips so those can't be adjusted but I've measured them both, and they are the correct length according to the manual.

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So would it be easier here to start at the top and work my way down instead of working my way up the usual way? Set 0 degrees on blade grips, then mixing arms, then washout arms?

 

[Westy]

from the bottom up normally as you are trying to get the swash in the sweet spot to get equal range on the pitch gauge..... no point doing it all from the top only to find your swash is hitting the head block or binding on the frame. It takes time ... but is worth it in the end

 

[DAL2855]

Yeah Westy, but since I'm confused about having these solid, nonadjustable links going up to the Blade grips, I can't adjust out the -3 degrees of pitch when everything else is level I guess is what I'm trying to say here.

 

[Westy]

Ok ... then you will have to do the trade off to get it to work. Is your swash about half way up the mast between hitting the head block and the top of the frame?

you will have to get that .... or will have big issues trying to get your pitch range or 20 degrees (+10 and +10º)

Because you only have 2 adjustment points ..... (servo to swash arms and swash to wash out base p links), and all the rest are solid.... you have not choice but to average it all out and get your assembly to just work.

Just eye up the swash ad mid stick into the mid mast position and then Zero out your master blade..... then check the range (make sure the head block does not get struck!) make sure you get your 20 degree pitch range and it is equal up and down from mid stick .... and then measure your master blade to swash link and adjust the slave blade to that dimension. Recheck you have zero ad mid stick and then your +10 at top and -10 at bottom and you should be good to go! There really is nothing more you can do. You may have to up or down the swash to get your range equal above and below the mid stick point, then re adjust your midstick and then recheck .... you may have to go round and round with this a few times until you get it right.

Then remeasure your market master blade link from the swash to the washout base and imitate that same measurement onto your slave blade. Then you are ready for the real tracking test ... again .... you will have to fine tune the SLAVE blade and not the master blade to get your tracking perfect ... do not adjust your master blade or you will get all your settings out again! Of course you will have to do your CCPM levelling top and bottom with tour travel adjusts before your head is put on ... but I am sure you have already done this right?

That is as good as it is going to get. the rotor system will do what you want it to do and most importantly your rotor system will do what is was designed to do.

Hope this helps your out.

NOTE:

1. I only concentrate on the master blade for all the setup .... or you are doing your head in trying to get every to work at the same time. Once you have done all the hard work ... you can simply transfer the linkage measurements to the Slave blade very quickly! - saves time and headaches.

2. MARK YOU MASTER BLADE AND BLADE GRIP

3. Once you have done your blade balancing (which should have been done well before this .....) you must not move that blade over to the other blade grip ... or you might get more vibration issues. This depends greatly on your balancing method. I Use the Dupro setup

 

[Tony]

Since you have non adjustable links, then there is nothing you can do other than adjust the swash links and the long links going up to the mixing arms. In this case, you will set your 0 and get your + & - pitch as close to the same as you can. You can now quit worrying about the arms being level. Yes, it is ideal, but there is no way to adjust non adjustable links.

 

[DAL2855]

Ok will try this method and see what I get! Thanks alot Westy and Tony for the great info about how to fix this issue! I use Tony's method of balancing the blades. Works great!

 

[Westy]

It Sure Does .....

I am ggon to try my good mates Dupro Balancer and see if I can get the complete head assembly including mainshaft into it! (I am sure you can do it)

 

[DAL2855]

Ok didn't have time today to work on this heli, but figured out that I do have the other adjustable links from mixing arms to blade grips, should I just take off the solid ones and use the adjustable ones? That would make this much easier right?

 

[Westy]

no need .... the solid link system that came out on the Sport and V3 and Pro .... are better as less adjusting needed .... only swash to servos ... .and swash to washouts ... done! Just go for it ..... you will be fine!

 

[DAL2855]

Ok will do Westy! I sure hope I can get this thing figured out now!