Logo 400 SE spec analysis

[Yoda DK]

here guys. a few pics. i use 3 shims on top of maingear. and 1 under it. hope im not wrong i would shoot my self

[egaus]

I don't have that problem. My main gear lines up nicely with my tail gear, using mod .5. I'll try some plastic blades.

e

[galensk]

Hi Yoda,

Manual says 3 shims on top one below...

I see that you're using the hollow main shaft. On the 400 this shaft wears fast on the bearing positions. This might not be the cause of you're vibrations but a place to check. Many 400 flyers use the hardened main shaft (MIK 04180) Maybe first we have to wait until you've checked the standard blades and see how this works out... The fact that you're 3mm below with the tailgear is maybe due to the different maingear which "looks" higher in the foto's than the standard gear...
/Kurt

[Bullfrog98]

I have heard a lot of guys complain about bad vibes using mod 0.7 gears. I know it's a bitch to swap everything out for mod 0.5 but if you are out of ideas it might be worth it just to eliminate one more thing.

I really don't think mod 0.7 is needed on the 400, I am swinging 500mm blades and have never striped a gear...... except when I had a few brain fart moments

If you are looking for bigger plastic tail blades the logo 500 ones work very well.

[Yoda DK]

Hi Kurt

yes i'm using the hollow mainshaft. i will change wenn its worn out or if it cause vibes. maingear is almost twice as thick as the mod 0.5 but my tailgear is also mod 0.7 so they are same hight. i'l get back wenn i get the shims and tailblades with an update but i thank you and the other guys so much for your help so far

Danny

[Yoda DK]

Hi Bull
if every thing else go wrong i'll change to mod 0.5gears. reason i bought it was because guys have talked alot about gear stripping with the 0.5gears didn't know the caused vibes i'll take a look at the L500 plastic tail blades. i honestly don't care what the look like. the should just be vibe free!

[galensk]

Originally Posted by Bullfrog98

I have heard a lot of guys complain about bad vibes using mod 0.7 gears. I know it's a bitch to swap everything out for mod 0.5 but if you are out of ideas it might be worth it just to eliminate one more thing.

+1 ...might be a last bailout... and no need to thank...We've all had our problems and the Logo guys always helped me out too... take care
/Kurt

[egaus]

Guys,

I just put on some plastic 85mm blades (white ones that came w/ my 600). I balanced the whole assembly, reset my boom at 90 - seems the vibrations were worse. I didn't analyze them but I can tell.

I also replaced the flanged bearings in the CF tail before doing this. I'm using the hardened main shaft.

I'm out of ideas. I've replaced every part that could matter, balanced over and over only to have the exact same result each time. Very frustrating.

e

[gravydrive]

It might be time to put it on the shelf, fly your other helis for a few days or a week, then revisit the problem with a fresh mind after you cool off. I've had to do that more than once, it's easy to get ultra-fixated sometimes, I've overlooked a lot of things this way (more recently than I'd like to admit... ).

[egaus]

Yeah.. But I need a flying 500 size heli or else I might go and buy another, yikes.

Here's some pics, camera sucks and everything is really straight (lens distorts some). The gear mesh shown actually has less backlash than it looks (it is more loose). I run a strip of paper through it and it looks good.

e

[egaus]

One of those photos has a mistake in it . Can you spot it? Even when corrected, it didn't change anything.

˙pǝxıɟ ˙ʎɐʍ ƃuoɹʍ ǝɥʇ ƃuıɔɐɟ sı ƃuıɹɐǝq ǝƃuɐlɟ puɐɥ ʇɥƃıɹ ǝɥʇ :ɹǝʍsuɐ

e

[Bullfrog98]

Man, you're not the only one getting despondent about this heli.

When you do your test runs on the bench do you disconnect the tail servo push rod? I'm clutching at straws here, but it's not maybe a jittery servo or something like that.

Also you say you can clearly see a vibration in the tail at the target head speed. Perhaps it is some sort of resonance issue that can be fixed with slightly shorter/longer tail support struts, or a brace between the struts? Struts are easy to make if you get the right thickness carbon rod from the LHS.

Apologies if these suggestions seem stupid, but I'm pretty much all out of ideas. I had some minor issues with the initial setup on my 400 but nothing like this. Perhaps you should just give it a break for a week and then give it a fresh look.

[Yoda DK]

egaus

just got really happy. thought you hat found what was wrong. but no such luck. i don't understand any of this. i have put alot of heli's together i have never had problems or vibes like this before

i think i'll take my heli apart today and do the build all over again. something must be wrong. i must admit that i already regret buying this heli. so many problems on a brand new heli and all the time spent on it instead of flying the thing

[Yoda DK]

Hi guys

a litle update. i got the 72mm edge to day.balanced them and put them on. heli was much smoother now. no loud and wild vibes. wenn spooling it up. but i do have 2 bad spikes

1: 11,70Hz rpm 702. vibes 428

2: 107,20Hz rpm 11232 vibes 760

after the vibes test i pulled the hole tail of. wenn spinning it slowly i get a click sound. so i guess i've got a bad bearing. i'll order new ones and try again..

[galensk]

Originally Posted by Yoda DK

after the vibes test i pulled the hole tail of. wenn spinning it slowly i get a click sound. so i guess i've got a bad bearing. i'll order new ones and try again..

Got that one too, changed the bearings in the tailgear and clicking was gone. I wouldn't change a thing at the blades now and check the vibes after replacing the tailgearbearings.
/Kurt

[Yoda DK]

i found a spare bearing,and changed it. vibe test again no difference. i'm now changing to mod 0.5 gears. do you use 3 shims on top of maingear? if do that. it will hit lower frames

[egaus]

Yoda, look at the manual, find online if you don't have one. It looks like you have the one-way in upside down? Check out my pic on the previous page. Hard for me to tell, I am at work right now but the gear should not be that low. Good job on getting your vibes down so far!

e

[Yoda DK]

your right i better take a break on this heli i'm starting to loosing it..

[galensk]

@e : good job noticing this . If this is corrected the problem migth be solved !!!
Danny will be airborne soon !!!!
/Kurt

[egaus]

I wish I had as much progress. Seems anything I do, the problem stays relatively the same. Messing with the boom angle and mesh is not doing much of anything it seems.

The thing that gets me is the heli spools up super smooth, up until the very end, at target RPM, where it gets loud and shakes. Argh.

e