450 Min/max Pitch?

Rob Lancaster

Rob Lancaster

Active Member
What do you guys think the min/max collective pitch can be set at on my 450?

I know the swash plate is still high or + because I can only get 10.6 deg. + before the washout block maxes out at the top.
The setting in the TX's swash, is only 70%+…
Thanks again in advance crew!
Rster...
 
D.O.G.

D.O.G.

Goblin 380 Supporter
This is just me talking but I like my pitch to be 13+/- on all three of my birds.
 
murankar

murankar

Staff member
Pitch is relative to head speed. A base line pitch is about 12 to 14 degrees with 13 being a good start point. Its all based on feel for a given head speed range.

I ran my X3 with 325mm blades at 13 degrees with a max head speed of about 3200.

I have been running everything lately at the lower end of head speed for an air frame and setting at 14 degrees. My 570 I was running just under 2000 at the low end and 2200 at the high end.

Th oxy team I have now I am running at 14 degrees at the lower end if the head speed range.

Get a feel for your set up and base It on feel. If its not snappy enough the add pitch. Don't exceed 14 degrees. Most kits won't be able to go more than that. Just to put it out there, with the exception of speed kits. Speed kits run 22 degrees. Lol.
 
Rob Lancaster

Rob Lancaster

Active Member
Ok cool! Just what I wanted to hear!
I figured it was about there.. Nice! Thanks and good morning. As for me,,, Good night from the middle of the Pacific..
Rster..
 
Tony

Tony

Staff member
Pitch is also going to depend on the person flying it. Some like a mushy stick so they only put in about 9º or so. Others like a very sensitive collective stick and will set it to 14º. I'm right there in the middle, my max pitch that I put on everything is about 12º, sometimes 13 depending on my mood lol. Try out each one and see what you think.
 
Rob Lancaster

Rob Lancaster

Active Member
Yeah, thanks to your excellent video on this procedure I knew I could tune the head a bit more and get back the missing degrees at the top end. I have some very calm weather approaching so I hope I can reset the swash and head in time.
Thanks again guys! I'll let you know how it goes,, of course.
Rster...
 
Rob Lancaster

Rob Lancaster

Active Member
Good day I had today!
I redialed in the head and the weather is improving so I got one flight in just before dark.
With the exception of a minor tracking problem she flies good.
Yeah after lowering the swash I can now get to 14 +/- degrees pitch.

The only little question I have is, why can't I get zero degrees at center stick? The reading on both blades are +.7 to .8 degrees?

Other that that I think the head is good. I still have a tiny tail wiggle but it's not so bad so I'll worry about that after I finish the head.
Stay tuned, flight testing continues tomorrow as the weather continues to calm down.

Ok that's about it for now.
Let me know your theories about that center stick thing.
Thanks,
Rster...
 
D.O.G.

D.O.G.

Goblin 380 Supporter
Rob Lancaster said:
Please elaborate for this guy...
Thanks,
Rster...
Click to expand...

Hey Rster. What URI is trying to explain is that the linkage from the servo to the swashplate needs to be adjusted longer or shorter to read zero degrees at center stick. For example, you mention both blades are + .7 to .8 degrees off. So since it's on the + side you probably need to turn the ball link holder a 1/2 turn toward the inside of all 3 servo links taking to consideration that the swashplate is level and the servo arms are at 90 degrees. That will get you closer to zero at center stick. This might take you a few times to get it right. In the manual, when they give you a length on the servo linkage, it just a guesstimate. It's a number that will get you close to center but not perfect. That's when you have to do your fine tune adjusting. 1/2 a turn here or a 1/2 a turn there. I hope this makes sense and helps you out.
 
murankar

murankar

Staff member
Your close, the links that connect to the blade grips are to long. The servo to swash links adjust the travel of the swash.
 
D.O.G.

D.O.G.

Goblin 380 Supporter
Sorry, my bad :(. I thought he had + 14/-14 on blade pitch already and swash was off. I should of said don't quote me.
 
Rob Lancaster

Rob Lancaster

Active Member
Ok, I think is starting to sink in. Sometimes I need to watch Tony's video on this multiple times to absorb it all, HA!

Just one further question.. Do I need to set the main trims back to center before I reset the swash links? The sub trims are set and the servo arms are level.

I flew 4 packs today and the tracking is good now and with 14 degrees pitch this thing yanks!! YANKS!!!
When I pour on the pitch though the tail jumps a good 90 degrees. But this problem is for another day..

Are we having fun yet...…… Yes, yes...…….
Rster...
 
murankar

murankar

Staff member
Now your getting into the same problem i have.

If your flying a fly bar heli then leave the sub trims. If your a flybarless system then yes remove the sub trims.

Now for the tail kick: you need tail pre comp added in. Since I don't know what system you have I can't tell you what to adjust. Generally you want to increase your pre comp for a tail right, nose left kick.

Now this can be a negative tendency of the governor also.
 
Rob Lancaster

Rob Lancaster

Active Member
I am flying a flybar HK450GT clone.. What about the regular trim? I figure it should be set to center, right?

Ha! Again You lost me on the tail kick.. I'm using a Spartan Quark gyro....
What is pre-comp??
Rster...
 
Tony

Tony

Staff member
I would try my best to not use trims and put all adjustments into the links rather than trim. Sub trim is only to center the servos and get the swash level, trim is to keep it flying (hovering) in one place without drifting. If you can do this mechanically, that would definitely be better.

As for pre-comp, I think you can connect to the Quark with your computer and do some adjustments that way. Been a very long time since I did anything with a flybar helicopter lol. But basically it is just a mix between the tail servo and the throttle. The more throttle you add, the more tail input it will give to keep the tail from kicking. But, with a Heading Hold gyro, you shouldn't have to do this if you have a good tail servo.
 
Rob Lancaster

Rob Lancaster

Active Member
Ok gotcha on both counts. And agree that it's better to set the mechanics good first. Then the radio will do the rest.
Oh, I know I can hook up the gyro with the computer, I just need to get the interlink cable.
The servo is a Futaba S9257...
Is the tail servo's frame rate dictated by the gyro? (properly set to match the servo),,, Or by the radio's frame rate setting?
 
Tony

Tony

Staff member
It will be set by the gyro. And if I remember correctly, that is a narrow band servo. I tried looking up the specs on that servo and could not find the center width, but I'm pretty sure it is 760µs. If the gyro is set to 1520µs, then that could be a lot of your issue and you could burn that servo up.
 
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