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Old Jul 08, 2009, 07:33 PM
Canadian Bacon
flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
12,903 Posts
Normal throttle is.5-25-50-75-100
" pitch is38-48.5-60-80-100

IU throttle is 100-61-51-61-100
IU pitch is 0-25-50-75-100
Sorry I'm late. Just out for another jaunt chasing the neighbors cat Didn't know cats could run so fast!!. Not really. Used to own my own cat.

Gord..
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Old Jul 08, 2009, 11:02 PM
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Ottawa, Ontario, Canada
Joined Jun 2009
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Ok, so I adjusted it. Nothing seems to make a difference on the sound. I did notice that I do in fact have more play than I thought I did. When I was pulling the motor back I was pulling by the motor housing. which tilted the pinion forward making it appear I had no play. Once I locked it down there, the gears weren't even meshing, I could turn the main gear freely.

So I shifted it forward using the paper method. When I do that and lock it down, it is tight everywhere, but when I get halfway around the main gear, if I put resistance on the head and turn the motor body by hand, the pinion skips on the main gear. So I tightened it up a little more than that, and now it doesn't skip by hand, but it's still just as noisy.

One good thing I don't see any new plastic dust coming off anymore. And I spun it up for a while. Gave it a good couple minutes spinning with no blades on.

Then I added the blades. And went through the whole pitch adjustment process (see my comments in the dx6i instructions page on this forum).

Once I had the blades pitch checked. Then I tried spinning it up with the blades on (only at like 5% stick on my bench just to see how it sounds with blades on)

And it's about twice as noisy lol...

Sounds kinda aweful actually. So I spun it to 5% stick and left it up for like a couple minutes straight, then let it wind down and checked. Still no additional plastic dust.. So I guess I'll have to take it out and try putting a couple batteries through it and see what happens.

Edit: Here's a vid of that spin-up... (my wife is the brave one holding the skid down so it doesn't vibrate off the bench) lol
First Bench Spin Up. With Blades On. (0 min 27 sec)
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Old Jul 08, 2009, 11:13 PM
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United States, AZ, Mesa
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OK it still sounds terrible... also, think about what would happen with your wife holding one skid, and the helicopter suddenly has a little lift...
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Old Jul 08, 2009, 11:33 PM
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United States, LA, Houma
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something still aint right bro!
the noise is there for a reason.
ill check in later to see if you resolved the problem.
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Old Jul 09, 2009, 12:02 AM
Cranky old fart
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Germantown, WI.
Joined Oct 2007
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Go buy some Align main gears. That one is warped and out of round.
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Old Jul 09, 2009, 12:49 AM
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United States, AZ, Mesa
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Quote:
Originally Posted by Balr14
Go buy some Align main gears. That one is warped and out of round.
Yeah but that's not causing the nasty screeching... I've had a wobbly gear like that and it worked ok, and certainly didn't sound like that. I would look at the tail drive gear too, and make sure it's clear of the top gear.
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Old Jul 09, 2009, 12:58 AM
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Germantown, WI.
Joined Oct 2007
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Quote:
Originally Posted by jasmine2501
Yeah but that's not causing the nasty screeching... I've had a wobbly gear like that and it worked ok, and certainly didn't sound like that. I would look at the tail drive gear too, and make sure it's clear of the top gear.
That's a common sound to an out-of-round gear that can't be aligned properly.
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Old Jul 09, 2009, 01:04 AM
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It's impossible to tell from the video, but I think an egg-shaped gear would make a warbling sound - not a constant screech. Take a close look at the tail drive gear - I had one that would run into the main gear, and it made a sound a lot like that one, and it peeled off a bunch of the white stuff.
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Old Jul 09, 2009, 02:46 AM
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Letchworth, Great Britain (UK)
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Quote:
Originally Posted by jasmine2501
It's impossible to tell from the video, but I think an egg-shaped gear would make a warbling sound - not a constant screech. ...
What I'm hearing from the videos is a wah-wah sound, not a constant screech Taken in context with the op's other comments about meshing being too loose on one side of the main gear, it seems that a new main gear is the appropriate cure.
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Old Jul 09, 2009, 07:11 AM
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Ottawa, Ontario, Canada
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Quote:
Originally Posted by jasmine2501
OK it still sounds terrible... also, think about what would happen with your wife holding one skid, and the helicopter suddenly has a little lift...
Oh I thought of that trust me. That's why I was making sure it never went any higher than 5% stick. it never spun up enough to have any lift. I would have used a bench clamp if I had one, I just didn't have one large enough to clamp on my new desk. lol...

But yeah any further spin up tests will be done outdoors from a safe distance. (she is the one who volunteered to do it, saying "Perhaps the gears sound funny because there isn't enough weight on them yet, why not put the blades on and try spinning it up that way" to which I argued about safety, but she is the one who convinced me to do it lol)

Anyway, trust me, safety was a concern.
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Old Jul 09, 2009, 07:36 AM
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Ottawa, Ontario, Canada
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Ok I went through a couple full rotations by hand. (rotating the motor housing) and watched the gear at the tail. It easily comes to within 1mm at it's closest point to the tail gear (vertically, due to wobbly) and at it's farthest it gets about 1.5mm away. So I don't think I really have that much wobble (it is more visible when it's spinning though I agree).

It also stays a fairly constant .5mm away from the tail gear shaft. And even though I agree, at one point on the main gear it is a little tighter, than at another point. I don't think it's very far out of round.

Earlier when I said I adjusted, but then it would skip in some areas, I wasn't talking about an extreme difference. When I adjusted it, where it was just meshing ok with paper in there, from one side, I must have been adjusting against the closest part of the gear. Once the paper was out it was far from "too tight" but on the other side it would skip if I held the head still with my hand and rotated the motor housing. (if I didn't touch the head it would turn it ok).

So I snugged it up some more, but that resulted in the same sound.

One other thing to note, I figured out this morning that when I was moving the motor, I was pushing on the motor housing. Then snugging the screws. When I do that the motor housing rocks toward the main gear, which rocked the pinion away from the main gear. This gave the illusion of looseness, then when I tightened the screws, the motor squared up, and probably over-tightened the gear again.

That's also the reason when I pulled it away I said I had no clearance. When I pull it away, the motor rocked away, and the pinion rocked toward the main gear. Making it appear closer. But if I pull it the farthest away, and then tighten the gear, I have about 1mm of clearance between the pinion and main gear. They don't touch at all...

I have watched through several rotations by hand, and I can't see the main gear rubbing anywhere... But then again when I'm doing it by hand it doesn't appear to wobble nearly as much as it does when spinning. (the wobble is very noticable visually when it's spinning). Is it possible it's wobbling more at higher RPMs? in which case it could be striking the tail gear.

Interestingly enough, there are a small amount of shavings on the bottom of the main gear itself. but not on the top. And I have noticed no new shavings near the pinion gear. Perhaps it is the main gear rubbing on something, but only at higher rpms?

I'm really at a loss here. I really want to get this heli out for a maiden flight. But if there is something mechanically wrong, I want to get it figured out first. I'm fairly mechanically inclined. But I'm completely stumped as to where this noise is coming from. I might be able to get down to the LHS this evening and have them take a look at the heli for me. See if they can see where the problem is. But that might be difficult today. (tomorrow their hours are a bit better)

Any further suggestions are GREATLY apprciated lol...

Thanks!
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Old Jul 09, 2009, 08:00 AM
Canadian Bacon
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Kingston, Canada
Joined Jun 2004
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The main gear may already be ruined due to the shavings. The shape of the gear teeth is very critical for smooth running. I'd go to the hobby shop and get the blue Align big gears for the T Rex, VA. I think is the version. Not expensive.Comes 3 in a package and not hard to change. You'll need them. I went through half a dozen due to crashes doing things I shouldn't have. They're tougher plastic than the white ones. Sort of starting from scratch. To set the gear mesh, just barely snug the motor screws, enough so you can still barely slide the motor in the slots. Using a screwdriver, pry on the screw against the frame to tighten or loosen the gear mesh. Once you get it right, then tighten the screws. It's a little more precise than pushing the gear in and out by hand. Like I say, it will take 4 or 5 tries before you get the gear mesh right.

Gord.
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Old Jul 09, 2009, 08:37 AM
Cranky old fart
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Germantown, WI.
Joined Oct 2007
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The clones I've built all needed better gears and one way hubs and the HK450 is the cheapest version from the same company.
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Old Jul 09, 2009, 10:59 AM
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Ottawa, Ontario, Canada
Joined Jun 2009
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Quote:
Originally Posted by flypaper 2
The main gear may already be ruined due to the shavings. The shape of the gear teeth is very critical for smooth running. I'd go to the hobby shop and get the blue Align big gears for the T Rex, VA. I think is the version. Not expensive.Comes 3 in a package and not hard to change. You'll need them. I went through half a dozen due to crashes doing things I shouldn't have. They're tougher plastic than the white ones. Sort of starting from scratch. To set the gear mesh, just barely snug the motor screws, enough so you can still barely slide the motor in the slots. Using a screwdriver, pry on the screw against the frame to tighten or loosen the gear mesh. Once you get it right, then tighten the screws. It's a little more precise than pushing the gear in and out by hand. Like I say, it will take 4 or 5 tries before you get the gear mesh right.

Gord.
Well the gear teeth don't look messed up yet. but maybe your right. Either way from your description I was likely aligning it completely wrong lol... (like fixing a laptop with a sledge hammer) lol... Looks like I need to try some finer adjustments and see what I can do. (I didn't realize it was that fine of an adjustment)

But yeah if I can't get it figured out myself I'll likely take it down to LHS and have them take a look see if they can figure out what's up (might be a bit easier if they can get hands on with it) And at the very least I could pick up a new main gear.
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Old Jul 09, 2009, 11:29 AM
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United States, AZ, Mesa
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Is it possible you don't have the pinion pushed all the way down and it's contacting the "curved bottom edge"???
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