300X - the HOW TO GET RID OF VIBRATIONS tread

[sn00p]

Whilst the rest of us are waiting on Lynx to come out with there offering :-)

[SHYguy]

Originally Posted by sn00p

Whilst the rest of us are waiting on Lynx to come out with there offering :-)

Amen brotha

[Stubbz]

Originally Posted by sn00p

Whilst the rest of us are waiting on Lynx to come out with there offering :-)

I would agree, i think the Lynx would be a better frame than MH. Anyone have any idea on when Lynx will be releasing one? Going into fall and hunting season for me so it wouldnt kill me to wait for Lynx to come out with some more goodies. But i'd buy the MH if i saw a big issue with the stock frame. Then again i have 2 frames so i can probly manige for a while.

[SHYguy]

That being said MH make good stuff too! From pics their frame look very nice.

It's just that Lynx test very thoroughly, they don't sell anything unless they are 100% satisfied with it. Same with Astroid Designs, amazing quality!

[SHYguy]

Originally Posted by SHYguy

I'm starting to suspect tha the shaft is already cracked on one side of the bolt hole. Can't wait to go home and check!...

No cracks as I can see... OK I guess a new frame as well then while we are waiting for a proper one... (and new bearings)

[Centurian]

I don't yet own a 300 but I did spend some time helping a 300 owner out... the frame around the main gear is crazy flexible. For the frame to flex at the maingear the 3 mainshaft bearings are trying to bend the mainshaft. My thought would be to omit the bottom mainshaft bearing as the frame below the mainshaft does not really need to be held rigidly. I believe the mainshaft is retained vertically by the mainshaft collar and the main gear so the omission of the bottom bearing would not affect mainshaft retention. I'm a bit old school I guess, but a straight line is defined by 2 points and a curve 3. Back in the day no helis including 90's used or needed 3 mainshaft bearings. I think it's worth a shot, I'll be trying it when I get me hands on a 300 if the frame appears strong/rigid enough without the bottom bearing.

[jcmo]

Originally Posted by Centurian

I don't yet own a 300 but I did spend some time helping a 300 owner out... the frame around the main gear is crazy flexible. For the frame to flex at the maingear the 3 mainshaft bearings are trying to bend the mainshaft. My thought would be to omit the bottom mainshaft bearing as the frame below the mainshaft does not really need to be held rigidly. I believe the mainshaft is retained vertically by the mainshaft collar and the main gear so the omission of the bottom bearing would not affect mainshaft retention. I'm a bit old school I guess, but a straight line is defined by 2 points and a curve 3. Back in the day no helis including 90's used or needed 3 mainshaft bearings. I think it's worth a shot, I'll be trying it when I get me hands on a 300 if the frame appears strong/rigid enough without the bottom bearing.

I think you might find there's a bit much flex in the stock frame when under load in the air to leave out the bottom bearing. The top is the least rigid part, IMO, and it's been well documented here how many different users have recognized the need for stiffening things up. Maybe you'll find something surprising that will help us all out if you experiment, but be careful! We don't want you or anyone else/your heli to get hurt

[John66]

Let's get this into the Sticky section. This is valuable stuff!!
John

[SHYguy]

I've already asked an admin to sticky some treads (one of them even has more hits than the existing ones)... but no reply...

OK - so finally up and running again! I replaced the frame + put in Boca main bearings, looks good now!

The problem actually seemed to be the anti-rotation guide. It was cracked/off - I just didn't see it. That was why it got this "whop" sounds when the anti-rotation pin came out of it's guide. But the guide then afterwards sneaked back into place to cover it's tracks

This probably also generated so much imbalance that the main shaft oscillated and rounded out the top main shaft bearing holder...

[jcmo]

Originally Posted by SHYguy

I've already asked an admin to sticky some treads (one of them even has more hits than the existing ones)... but no reply...

OK - so finally up and running again! I replaced the frame + put in Boca main bearings, looks good now!

The problem actually seemed to be the anti-rotation guide. It was cracked/off - I just didn't see it. That was why it got this "whop" sounds when the anti-rotation pin came out of it's guide. But the guide then afterwards sneaked back into place to cover it's tracks

This probably also generated so much imbalance that the main shaft oscillated and rounded out the top main shaft bearing holder...

Great to hear you got it tracked down! No more mystery noises... I suppose that could be a source of vibes too, if the AR guide wasn't securely holding the pin.

[m1crochip]

I've had this mystery afflict me very early in the season, and I've yet to resolve it. I was flying with the wicked (even at 11t) with the lynx brace for a couple of months with no problems. One day, WHACK! I don't know what caused it, but it was never able to get to higher headspeeds without the aforementioned vibes.
Now, with new frame, mainshaft, mainshaft bearings, feathering shaft, dampers, head, tail assembly, different gyro tape, ect, etc, and Scorpion 2314, I'm still unable to go over 64% throttle with a 14t pinion. 64.5 throttle or over and it goes nuts. When I first installed the scorp, I had Idle up at like 70% - it didn't shake and roll like it usually does, but it was very unstable and rocked fore and aft. Never been crashed.

ShyGuy - are you still fine with the boca bearings? I've changed to new stock bearings with the same result.

I'm sick about how much money I've sank into this thing for nothing. I knew I should've just bought the align 450DFC pro - I'd be way ahead money-wise.

I suppose I could just fly it at like 62% throttle, but WTF happened??

The only things that haven't changed are the motor mount, swashplate, and blade grips. This fiasco has kept me from flying pretty much the whole summer.

[Thorvald]

Has anyone tried balancing the main gear yet?

Using a prop balancer for example. It certainly seems to move around a lot.

Cheers
Tim

[Nelsonisms]

Originally Posted by Thorvald

Has anyone tried balancing the main gear yet?

Using a prop balancer for example. It certainly seems to move around a lot.

Cheers
Tim

I haven't really felt the need to do so, especially after switching to the Lynx gear & hub.

But, I did run across this video a while back where this guy did it and thought about giving it a go since I have one of those Du-bro balancers for the props on my planks...

Balancing the main gear assembly, Blade 300 X (2 min 3 sec)

[m1crochip]

I'll add that the vibes are less with less belt tension, until it's too loose and goes nuts from that. So, it seems that the harder the belt pulls on the main and tail shafts, the more the vibes are amplified. Maybe it's the tail frequency at that rpm messing up the BX... I've balanced it as best I can with the stock blades on the align hub/grip holder, but maybe the bearings are moving around in the tail case or something. I think I'll try removing the lynx stiffener and see what happens as I've never flown without it...

[SHYguy]

Originally Posted by m1crochip

I've had this mystery afflict me very early in the season, and I've yet to resolve it. I was flying with the wicked (even at 11t) with the lynx brace for a couple of months with no problems. One day, WHACK! I don't know what caused it, but it was never able to get to higher headspeeds without the aforementioned vibes.
Now, with new frame, mainshaft, mainshaft bearings, feathering shaft, dampers, head, tail assembly, different gyro tape, ect, etc, and Scorpion 2314, I'm still unable to go over 64% throttle with a 14t pinion. 64.5 throttle or over and it goes nuts. When I first installed the scorp, I had Idle up at like 70% - it didn't shake and roll like it usually does, but it was very unstable and rocked fore and aft. Never been crashed.

ShyGuy - are you still fine with the boca bearings? I've changed to new stock bearings with the same result.

I'm sick about how much money I've sank into this thing for nothing. I knew I should've just bought the align 450DFC pro - I'd be way ahead money-wise.

I suppose I could just fly it at like 62% throttle, but WTF happened??

The only things that haven't changed are the motor mount, swashplate, and blade grips. This fiasco has kept me from flying pretty much the whole summer.

Sounds like exactly the same problem as me.

Mine is still not good. didn't replace tail case bearings yet.

I'm kinda starting to think the Scorp is too much for this frame. May try to go back to the Parkfly...

Hopefully the Lynx frame will be here soon!

You could make a tail case belt roller in order to run the belt looser.

[Stubbz]

Shyguy recently you mentioned a new pinion that's out I think from Lynx that can be used on a larger shaft size like a 450 motor. Think it's possible to use a 450 motor in the 300's? I'm sure it would be to much for the stock frame but maybe not with Lynx frame when it's out. I just keep thinkin you mention your 300 is way to heavy now being setup well but a 450 motor could really resolve that or make it even worse I guess.

Or is the Scorpion motor your using basically one for a 450 or just a bit smaller?

Theres a couple of you that have good setups overall but still some vibe issues that idk if the Lynx frame would resolve completely or not but i'm afraid to build a nice setup heli and have it still not be right, to me it wouldn't be worth owning at that point n i'll just keep wishin I went 450.

[Nelsonisms]

I'm just a little baffled by all this. My 300X seems to be smooth as silk with basically the same setup. I definitely haven't been running my belt loose. Not crazy tight, but not exactly loose either. If you can rule out the bearings or any bent parts (main shaft, main hub, motor shaft, feathering shaft, tail shaft, tail hub, etc.) then it seems to me there has to be some give and/or warp somewhere in the frame that's causing this. Have you double checked all of the screws in the frame to make sure they're not under or over tightened? Are any of the screws stripped out, particularly the ones surrounding the main shaft bearings? Same thing with the tail case?

[SHYguy]

I had no vibe issues for a loooong time, with stock, Wicked and Parkfly. A few packs into the Scorp it's never been the same again. I've went over it several times... it outta fly good That being said I just discovered that my cyclic servos are totally messed up (or the iKON, but not likely). That could be a cause too... (they move out of sync)

Weight: I've almost finished my Gaui X2 build now (also 300 size). It couldn't be more different from the 300X! I've yet to fly it but others can testify it flies great. It seems the 300X is over engineered, or simply too beefy and heavy to be correct. It's more of a shortened 450 really. With a proper frame a stretch kit to 450 would be a good idea in order to reduce disc loading. So Stubbz yes you need to crank up the HS to compensate. I'd say a 450 motor is over the top though.

If you have space I'd defo sell and get a 450 or larger! Check out the new Align Dominator?

[Stubbz]

I have space at home but 450 would be on the edge of what I could do here but I don't get to fly that much at home anyhow with the family and such anyways so a 450 would be nice along with my 500 for when I go to the field and itd make me go to the field more often, only have 2 bats for my 500 and at $100+ each I don't plan to have a lot so a couple for a 450 would make a nice trip to the field not just for 2 batteries. Now that I have a full set of savox servos I could keep beastx then build off a dfc airframe for cheap n not have to worry about havin a $600 300 shortly. I want more of 450 stability than anything the 300 seems more microish to keep in the air, few more batteries will confirm if the wind would ever stop blowing 50mph.

[Nelsonisms]

On a different note. I seem to recall someone (DCH or SHY) had tried running the aluminum tail grips on your 300X a while back. I had actually bought some months ago, but just decided to stick with the TRex 450 tail hub assembly since it was flying perfectly that way. Well, on a whim I decided to go ahead and install the Blade aluminum tail grips and the carbon fiber tail blades this weekend to see how she flew. I wanted to try it because I discovered the carbon fiber tail blades do not fit in the TRex grips because they make contact with the bolts.

Like a jackass I didn't spool it up on the bench with just the tail blades to make sure the vibes were in check. Luckily I was ready for issues and hit throttle hold just before the right-roll-of-death tried to make an edger out of my main blades. I took the main blades off and spooled it up at the field...sure enough...crazy vibes causing the swashplate to tilt. I then put the TRex tail hub/grips back on and she's smooth again.

At home I put the Blade tail hub/alum. grips on my prop balancer to see what's going on. What I expected was that one of them would be heavier than the other, but that doesn't seem to be the case. It always comes to equlibrium right in the middle where the blades are pointed out horizontally. So I don't think a difference in weight is the issue. So I can only assume that there is just too much mass in these aluminum grips with the chinese weights installed.

I guess I'm content to stick with the TRex assembly if the Blade aluminum grips are going to cause these kinds of headaches, but I am interested in any advice as to why this setup should cause such high vibrations given what appears to be perfect balance.

Also has anyone else seen this issue with fitting the carbon fiber tail blades in the TRex tail hub assembly. Since they're just collecting dust now, I thought I might try to file down the root a bit to see if I can get them to clear the bolt.