Couple of Build Questions

[hoblium]

Hi all, first Mini P here.

I see the kit comes with shims for the head, how important is is that I get any side-to-side play out? Do the shims go against the dampers, or against the grip?

Also, looking at Mr. Mel's calculator, the 16T pinion with the 2580kv motor would be 3459 at 75%. I am thinking I'd probably want to be more around 3200. Is 65% throttle a comfortable place for the stock YGE, or am I better off with the 15T?

Lastly, it seems like the part of the main grips that hold the balls is running against the hub, just barely. Is this cause of concern, or will it be fine under load?

Thanks in advance!

[Aryemis]

Originally Posted by hoblium

I see the kit comes with shims for the head, how important is is that I get any side-to-side play out? Do the shims go against the dampers, or against the grip?

The shims go between the head and the dampers, and there should be no side-to-side play at all, it's normal if they feel slightly notchy, they should be pretty free if you pull on them a bit.

Originally Posted by hoblium

Also, looking at Mr. Mel's calculator, the 16T pinion with the 2580kv motor would be 3459 at 75%. I am thinking I'd probably want to be more around 3200. Is 65% throttle a comfortable place for the stock YGE, or am I better off with the 15T?

I run 3000-3100 rpm governed on the YGE, and have no issue whatsoever. No clue what % throttle it is as I've never ran it without the SK governor.

Originally Posted by hoblium

Lastly, it seems like the part of the main grips that hold the balls is running against the hub, just barely. Is this cause of concern, or will it be fine under load?

I don't understand what you mean, but it doesn't sound normal. It should be pretty clear in the manual though (well it sounded clear to me and it was my first build so ...)

[sp00fman]

Upload some pictures of the whole heli. You will be surprised how many things we can tell.

[hoblium]

Thanks guys, I will post up a couple of shots when I get home from work.

[hoblium]

Here's what I mean about the grips rubbing

Sent from my Nexus 4 using Tapatalk

[keyscrt]

Don't know if its the picture but it doesn't look like your balls that screw into the grips aren't aligned with each other they should be just looked at mine and they are. Also looks like the dampners are sticking to far out.

[Shtumpa]

Originally Posted by hoblium

Here's what I mean about the grips rubbing

Sent from my Nexus 4 using Tapatalk

Slight touching wont be an issue, they will seat in ..Just make sure the ball screw end is not poking thru and rubbing on the head block.. they are a plastic molded part so sometimes you get this, you can bend it out a bit..or remove the grip and scrape a bit of plastic off with a sharp knife.. But really it will be ok ..

[Shtumpa]

Originally Posted by Aryemis

The shims go between the head and the dampers, and there should be no side-to-side play at all, it's normal if they feel slightly notchy, they should be pretty free if you pull on them a bit.

+1 so fit shims into head first then push in the dampeners, then put grips on and do up, slight notchy feeling on the grips is normall and ok..

[sp00fman]

Something strange about how your rubber dampners stick out of the headblock. Mine are close to flush with the main hub when the grips are screwed on. I only had to use one tiny flat washer on both sides.

Did you use the correct spindle spacer? There is a standard one for use with the flybarred featheringshaft/spindle and a fatter one for FBL spindle use.


If the plastic grip arm does bind with the main hub you could sand a tiny bit of plastic away if you like.

[baui2000]

Others have said it, dampers are sticking way too far out of the head block. You will have huge phasing issues if you fly it like that, so go by the manual and fix it.

Sand the arms a little. Rubbing won't cause any issues if you don't but why keep it less than perfect?

15T pinion would give you a bit more efficient drive train that will be easier on the ESC and packs but 16T will work fine as well.

Those spacers are not only to get slop out of the head (which I never had an issue with) but to correct for slight variances in phasing as well. Here's what you are looking for...

When you turn swashplate so that balls holding the follower arms are aligned with longtitudal axis of the helicopter like so...



...spindle shaft has to be correctly aligned with the longtitudal axis as well. Not like in following images which show phasing error close to 10°:



In other words, when you turn swashplate like in the first picture, you want to have the spindle shaft (and blade grips) perfectly aligned with the longtitudal axis and 90° angle between the swash balls and grip arms.



I shot these last year when I was hunting down some cyclic wobbles. Turned out the set of follower arms I used was molded wrong and moved the head out of phase... Issue was different than yours, result the same.

[hoblium]

Thanks all. I will pull the head apart again and see what I can do.

I got a closer look and I don't think the screws are rubbing, and the grips may have actually 0.5mm space.

But I will add the shims, make sure the dampers are seated properly and maybe tighten the spindle bolts a little more (I made them barely tight to help the grips rotate more smoothly).

[sp00fman]

Make the bolts snug so the threading is all the way in the spindle. If you leave it partially in, the screw will break on its threads over time due the blades flapping in flight, Dont torque them down hard. Any excessive force on the threads will be added to the force from the blades pulling of them in flight. If you exceed the bolt strength you know what happens. Let loctite do its job of preventing the bolt unscrewing, not torquing it down.

[CrashAddict]

Yep. Spindle bolts need to be tightened down all the way. Double check you are using the right spindle and spacers.

[hoblium]

Hmm, very odd. I followed the above advice. I currently have 4 shims on each side and still have play.
Without shims (but with a ton of play), the ball grips line up nicely. As I eliminate the play by adding shims, the ball grips no longer align. It appears that my feathering shaft is too long! When I tighten one side of the spindle, then pass it through the grip, hub, and other grip, the shaft sticks out 1 or more mm post the radial bearing, so no matter how much I tighten it, there is still play.

It is 53mm. While not listed in the manual (v2.0), a little research tells me that is the right one. Also, I got one of the newer kits that only has the low head.

This is very frustrating! Am I better off with side-to-side play or mis-aligned grip balls?

[keyscrt]

Is the stepped face of your dampners facing out ?

[CrashAddict]

No need for 4 shims. Even with one shim there is no play. Perhaps your spindle was made too long. Do you have all the bearings and spacers in the grips properly?

[CrashAddict]

You sure you have all the bearings in? There are 2 radials in each grip and a 3 part thrust bearing and a thin shim. When the grips go on the feathering shaft should be flush with the outermost radial bearing.

[hoblium]

Okay, the plot thickens, well, actually not really...

I pulled both grips apart to make sure they were right (they were), but now when I put it back together, it's fine. I know you must think I am nuts, but I swear I didn't do anything differently than I did the past 12-15 times!
Is it possible I originally pushed the bearings in too far into the grip? Is that possible? I'm thinking no, but I have no other explanation.

If the bearings weren't seated properly, you'd think the spindle would then be too short.

Maybe swearing and throwing things around my office helped?

Feel free to throw things at me guys, this is really embarrassing! I really do appreciate all your help.

I will keep you posted, the maiden probably won't be for another week.

[Shtumpa]

Originally Posted by hoblium

Okay, the plot thickens, well, actually not really...

I pulled both grips apart to make sure they were right (they were), but now when I put it back together, it's fine. I know you must think I am nuts, but I swear I didn't do anything differently than I did the past 12-15 times!
Is it possible I originally pushed the bearings in too far into the grip? Is that possible? I'm thinking no, but I have no other explanation.

If the bearings weren't seated properly, you'd think the spindle would then be too short.

Maybe swearing and throwing things around my office helped?

Feel free to throw things at me guys, this is really embarrassing! I really do appreciate all your help.

I will keep you posted, the maiden probably won't be for another week.

Tell us the overall length of your spindle and width of the spacers you are using between the grips and dampeners

[hoblium]

Originally Posted by Shtumpa

Tell us the overall length of your spindle and width of the spacers you are using between the grips and dampeners

The overall length was 53mm, I didn't measure the spindle spacers while they were off, but from what I can tell measuring them installed, they look to be 1.5mm.