btm123

I'm suffering vibration on my esky Lama V4. It was second hand and to be honest I can't remember if it has alway done it or not, but it seems to be getting worse. I'm a complete beginner to all this BTW.

It is most noticable on the tail with an up/down motion (no left right). It is enough to vibrate the heli along a wooden floor at slow enough rotor speed where there would be no lift. I assume this is not normal - certainly my big lama is super smooth.

I had some xtreme blades on it so switched back to new esky basic ones, but that hasn't made a lot of difference - maybe a little but not a lot.

I've tried it very briefly and slowly with blades off and flybar off - no vibration.
Blades on flybar off - still vibration
flybar on, blades off - still vibration

So it doesn't look like duff blades or bent flybar, unless both are slightly out. Seems that if there is any weight on it vibrates.

I've taken the body off and cannot find anything loose. However, I did note there is more flex in the main body (the bit between the two motors) back to front than there is left to right? Though it doesn't look like it is loose, more the flex in the plastic by design.

Is there anything else I should be looking at, or is this just normal on these helis? Seems to fly OK, and the vibrations do lessen at speed, though they are still noticable when flying.

Thanks

pgroom_68

Hey again mate,

The good news is it is probably easy adjusted out. You want to (in very small increments) adjust the "gain" pot on the side of the 4in1 - no need to unplug/replug the lipo for these changes to take affect either CCW a tiny bit to loosen the gyro gain hold on the bird is a good start.............

Peter[sm=shades_smile.gif]
P.S. A small flat-bladed screwdriver is all you need for this[sm=49_49.gif]

btm123

Thanks again Peter,
Still not sure about this one.
I adjusted the 4 in 1 and had things pretty smooth with the stock blades. A bit of slight wobble powering up through the slower revs but smooth once up to speed. Much better anyway.
But I then put the Xtreme blades back on and its back how it was, so I'm thinking one of these is out of balance or warped.
I have 4 more new Xtreme blades in a packet so will change them all and see what happens next.
Tried the Big Lama again though and that is super smooth, so something isn't quite right with the V4, it isn't just my imagination. Hopefully it will just be the blades.

Will let you know how I get on - I've run out of time for a couple of days now.

pgroom_68

Hey again mate,

When you do get time - you should static balance your blades as well. It seems (from what you've said) that one out-of-a-pair of blades is heavier than the other. This shouldn't make a big diff. unless the diff. is huge - but obviously there are other factors as well. A new Extreme warped blade is a possibility - although remote also.
If you change blades for other Extremes and the wobble is still there - it may be the shaft bent - and only with performance blades you notice it. There is one more possibility - [sm=72_72.gif]that the "top link" (which you spent a lot of time adjusting for the stock blades) may be damaged in some way, so it cannot be adjusted for the Extremes......sound feasible??[sm=49_49.gif]

You can balance each individual blade by measuring its weight with its "paired" opposite. You may add weight to the lighter of the two, by adding electrical tape to a non-conspicuous place (usually the underside near the middle).
...Or (pic below). This identifies the heavier vs lighter blade if you don't want to remove individual blades and weight them with digital scales (or you just don't any any accurate scales)
When you have the two blades fairly close it will run a lot smoother.........

Anyway, I hope your luck improves, and I'm glad you are having great success with the BOL mate!

Peter[sm=shades_smile.gif]

pgroom_68

I'm off to my heli-meet now. Read you later mate!

Peter[sm=shades_smile.gif]

btm123

Hi again Peter,

Yeah, good tip with the balancing. I'll give that a go when I have more time, though I'm doubting both sets of blades can be duff now.
I've spent 30 mins tonight, and you'll be pleased to hear I took some video

I took the old xtreeme blades and flybar off and spun the shaft. The lower shaft was very smooth to the touch, but the upper one had quite a bit of vibration to it when touching it.

NEW set of xtreme blades on and we are back how we were:

http://rfmisc.homeip.net/heli3/MVI_0770.mp4

I'm assuming this is not as it should be?

On closer inspection the upper blades have a lot of play in them at the tips, as if they need aligning. Lower blades seem pretty uniform and level though.

http://rfmisc.homeip.net/heli3/MVI_0773.mp4

I placed the blades back to back before putting them on though, and they seemed perfectly aligned, so I'm starting to think it isn't the blades.

So, either I've got 2 sets off duff blades, or something else is causing them to spin off centre.

Correct my thinking but I'm starting to think the inner shaft is slightly bent? This in turn is causing the back forth movement of the heli, up down movement of the tail, and up down flight path of the tips of the blades?

Any other ideas?

I guess my next step is :
1. to take the shaft out and see if it is visibly bent.
2. Check the blades are balanced, though I think this is a red herring
3. put up with it, though I'm worried I'll just get more wear and tear on other parts.

Thanks

pgroom_68

Hey again mate,

Yip - that looks familiar! My son (who has seen my helis for a few years now) just came past and seeing the video said "Hey Dad that's a bent inner shaft - right?". It is a pretty bad case - but not too uncommon........[sm=49_49.gif]

90% chance of a bent inner shaft - 60% chance of outer shaft being bent also - 25% chance that your upper bearing race has collapsed. Mostly just caused by hitting stuff in "newbieness" - either you or the previous owner[sm=wink_smile.gif]

You can straighten an inner shaft to nearly perfect again by hand (rolling on glass allows you to see any imperfections), or order another (extended) [link=http://www.rchelicoptershop.com/catalog/lp0002-turbo-shaft-for-lama-dauphin-comanche-p-342.html?osCsid=06570c9r4dvnt3tt00c4js14f3]Turboshaft[/link] - its your choice.
Within the Turboshaft link is a couple of videos to watch - and note that when you do order you get a spare extended shaft also
I suggest do both - order the Turboshaft and while you wait for it to be shipped to your location, try straightening the one you have.......

To replace inner shaft with Turboshaft - [link=http://www.youtube.com/watch?v=qDbWHTgm3ZU]HERE[/link]'s a instructional video!
I don't agree with the vid in one regard. Chris shows that you should remove the screws from Gear A all the way out - just back them off to 3/4 way out IMHO.

Happy viewing[sm=49_49.gif]

Peter[sm=shades_smile.gif]
P.S. If you need disassembly, shaft-straightening, or outer shaft tips - just ask[sm=49_49.gif]

btm123

Thanks Peter (and Son),
Another very helpful reply.
I'll get this apart and see if either of the shafts are obviously bent. Any chance you could elaborate on what the upper bearing race is so I can look for that, and what the part number is for it?

If it is just the inner shaft then its not a problem, but if it turns out the other stuff is bust I'm not sure its economical to repair.

For info, I paid AU$50 for the Lama second hand. I can get a new one from a local dealer here for AU$95.

To fix I might be looking at AU$8.50 for a standard inner shaft, AU$10 for an outer shaft, and maybe another AU$10 for the bearing race, assuming nothing else is wrong. I'm just not sure that is economical.
I also reckon I might even get the AU$50 back for it on ebay for spares.

I dont want to spend a lot on this heli either, the BOLis going to be my primary heli.

Decisions decisions. I think the best think is to get it stripped and see what is visibly bent and whether it can be straightened. I'll let you know how I get on.

And thanks for the offer - I'm sure I'll be back with more questions. Sorry to be a pain

btm123

Actually, to save this thread bouncing back and forwards between our respective time-zones, what are my options for straightening what I've got? I'd like to get this stripped down, attempted straighten, then back together again before I forget how it came apart in the first place

I'll roll on a glass table to test for testing straightness - I've already seen a vid on that on youtube. Not found anything that looks easy on doing the actual straighteneing of either shaft yet though. Have you any tips?

If it looks like just an inner shaft I'll buy a new one, but on the assumption it might be more I'd like to try to straighten everything I can.

Thanks

pgroom_68

Hey again,

I know what you mean about "bouncing between time-zones"
By "upper bearing race" I was refering to the [link=http://www.rc711.com/shop/bearing-263-for-esky-lamas-p-148.html?cPath=166_22_40]bearings[/link] held within the black plastic [link=http://www.rc711.com/shop/bearing-set-collar-for-esky-lamas-p-47.html?cPath=166_22_40]holder (on the left)[/link] at the top of the outer shaft. You can easily pull the holder off the top - and sometimes the race comes out of its holder when the inner shaft is removed. If the bearing looks (all the steel ball bearings within look present) and spins smoothly (you could pass the removed inner shaft back through it and rotate it by hand) - I think it should be OK!

The inner shafts of coaxs (the Big Lama included) can all be manipulated by hand - the trick is to find exactly where the bends are - simple or complex - and in which directions they flow.
Here is a couple of tips that I have picked up on my journey: Drill a hole in a piece of timber (4" x 2") a couple of drill sizes smaller than the diameter of the inner shaft. View the video (linked above) and follow it to remove the inner shaft from your helicopter, and tighten one end in a "cordless" (battery) drill chuck. Spin fast enough that the bends become obvious. Push the shaft through the hole in the wood to straighten it - sometimes not easy to do!! Edit: I'VE JUST HAD A THOUGHT - this might not be possible with a stock inner shaft due to the plastic head. Buying a Turboshaft may be the only option you have as you can remove the aluminium head with a grub screw.
With your bird in this condition (inner shaft removed) it is easier to see the wobble of the outer shaft. Trying looking from above also.

Caution: safety first!
Ensure that you undo the shiny phillips screws and remove the lower grips also (still holding the blades) - or hold your bird at arms length - those blades hurt if they hit you!

One more tip for checking possible bends in the outer shaft. A felt-tip pen held close (but, for the most part, not quite touching) the shaft as it slowly spins will mark any of the larger bends quite clearly![sm=49_49.gif] Then it is a matter of hand-bending as best you can. But the outer shaft may still be relatively OK - judging from the videos though - it has taken quite a bit of abuse and may need some attention!

You (or your wife) may have some [it is know by many names]: 3in1 (light) sewing machine oil. One drop (try to get it between the actual ball bearings) AND your motor shafts (below the pinion, on the actual motor shaft where it "disappears" into the motor) will help heaps with smoothness. The only thing that I recommend you buy immediately (if you don't have any access to it already) is: silicon-spray - not WD-40 . Before you reinsert your inner shaft, spray it liberally along its length with silicon-based spray! It works wonders lubing & eliminating binding and quiets the bird down heaps {although yours sounds like it has chipped a tooth on one of your main gears also} for a long time - long enough to last until the next time you remove the inner shaft (usually).......[sm=regular_smile.gif]

If you need to order bearings 'cause they are adding to the problem, try searching on fleabay.co.uk for " bearings 2.6.3 " ...or {I'm sure there is either an on-line or walk-in Local Hobby Shop (LHS) in London that stocks esky parts} ...or order them from [link=http://www.miracle-mart.com/store/index.php?main_page=product_info&cPath=80_204_149&products_id=201]Miracle-mart[/link] - whichever option is cheaper (remember to factor in shipping) and faster!!
I think MM has cheaper shipping than rc711[sm=wink_smile.gif]

Wow - that has turned out to be a long post...................[sm=red_smile.gif]

Peter[sm=shades_smile.gif]
P.S. At the prices you posted, I think you are wise not to spend too much $ on this bird!
P.P.S. It all depends on what you find is actually bent - but the Turboshaft includes the (removable with a grub screw) aluminium head (with a cap to hold your flybar in place). It is a good buy $-wise if you only need to replace the inner shaft (as it widens the gap between the "blade planes" by 2cm (20mm) which totally eliminates blade strike!)

btm123

Hi Again,
And thanks again for all that.

Well, I've had it stripped right down tonight.
The upper bearing seems fine. I could take the plastic casing off and the bearing stayed in. Spun freely, and no signs of any problem.

Inner shaft looked straight. Rolled pretty well on a table (dont have a glass one) but always stopped rolling on one of the outer sides - I guess they have more weight to them. But is was a different one of the two each time, not the same one each time which would indicate shaft was bent.
I did the drill test, and it looked like there was some slight wobble, but very very slight, and in my opinion more likely to be the hold the chuck had on it than a kink in the shaft.

Anyway, I did some diy straightening anyway to make sure. My Black and Decker workbench (not sure if you have these in Oz) had a long wooden vice with a groove in it width ways. I was able to use cardboard to pad the groove enough to allow it to grip the blade tightly and was able to spin the shaft. Tried the drill afterwards and it seemed the same to be honest.

Had less luck with the outer shaft. The screw was so tight I couldn't remove it, and I also just couldn't get a grip with my micro screwdrivers. To add to it I look to have stripped the screw head a bit too now. Not sure how I'd ever get that off, but I'll worry about that another day.

In the heli the outer shaft seemed pretty straight to me. Didn't do the felt tip test as visually it just wasn't out. To the feel it maybe had some vibration, but then again that was probably the motors/gears right next to it.

No gears were missing any teeth.

Managed to get it all back together, silicone spray on the shaft too.

Problem still persists, though as before it seems to fly OK.
Not sure if it is slightly better than it was, as battery died on me during testing. I'll have another go soon, and also try adjusting the gain again to see if I've actually made any difference.

Still a good hour ot two's work, and feels good to have taken it apart and still have it flying. I'm sure the first time is always the worst.
I'll update you when I've charged the battery and experimented more.

But basically, there is nothing obvious to me. If the shafts are bent, it is by such a tiny amount. To put it in perspective, if they were properly bent I seriously doubt anyone could straighten them to as good as they are now. But of course Imay be wrong.

Thanks again for the assistance though, it is much appreciated. Whilst I'm reluctant to spend money when there is nothing obvious, I'll perhaps try an extended inner shaft as a last resort. I'll see how I get on once i'm charged and take it from there.

pgroom_68

Hey again mate,

It is not very confusing to me at all - in the above videos the symptoms all point to a bent shaft. Which shaft is the only point of contention! If you are sure that the inner shaft is pretty damn straight - then it can only be the outer..... Perhaps you should be ordering a cheap [link=http://www.helibuy.com/esky-gear-shaft-b-ek10557-p-101.html]outer shaft[/link] (the "B" gear comes already attached).
When you spun it up (with the inner shaft removed) the slightest sideways movement of your outer shaft (or wobble) will be magnified to your blades Even if the actual shaft appears perfectly straight - looks can be very deceiving........

I know you don't want to spend very much cash on this bird 'cause you have a much more popular BOL, so I have searched (using my bookmarks) for the cheapest outer shaft + shipping to you that I can find. To the above outer shaft you have to add £1.19 for shipping and wait for a 14 day lag time........[sm=49_49.gif]

Sorry, I don't understand what you are saying in the bolded area above[sm=confused.gif] The idea with the timber is to pass the inner shaft through a slightly smaller hole (enlarging the hole by pushing it through), and this will bend the inner shaft back to perfect! A medium drill speed is best. Is that what you did?? Did you remove the blades (still within their grips first?)

Peter[sm=shades_smile.gif]
P.S. Tip: Try heating the head of the grub screw a little with the tip of a soldering iron to release the thread-lock - sometimes it works!![sm=regular_smile.gif]
P.P.S. Yip, Black & Decker and Ryobi are two of the best-selling brands here.

btm123

Hi again Peter,
Have dismantled once again!
I have forced off the screw holding the outer shaft collar and taken the outer shaft out. Rolling it on a table I can now see this is the culprit, as you already guessed.
It's not massively bent, but always stops in the same place, and definitely isn't 100% straight.

Some other stuff that may or may not be normal which may confirm this:
1. The top bearing would not go over the hole in the shaft without a lot of force with plyers. Was spinning OK though.
2. The bottom bearing by the gear would not slide up the shaft, but was spinning smoothly. On attempting to help it off with plyers the bearing broke completely.
3. The exploded diagram on my instruction book seems to suggest the gold coloured washer underneath is just that, but it seems attached on my shaft. I'm wondering if the design has changed.

SO despite not wanting to spend too much I've actually had to order quite a bit of stuff:
A new Outer Shaft EK1 -0557
New bearings to fit this shaft after one was stuck/broken- EK1-0328
A set of screws just to get the gold washer - EK1-0573
And a new EK1-0324 collar set to replace the one I struggled to get off.

After all that I decided Ibetter order a new flybar and stock inner shaft (it was only a couple of quid) just in case they also got damaged at the same time. If they didn't, I guess they will at some point in the future anyway.
I didn't want to spend the extra on the extended inner shaft until my flying improves!

And to cap it all I was just under the free shipping threshold, so got a spare set of skids for the BOL in anticipation of my next crash with that!

It came to about £22 in all, and I'll have it next week.

Would have been quite a bit cheaper but I've been a little unlucky with the miscellaneous stuff that hasn't come off cleanly and has bumped the price up. Still, I expect you are used to these complications by now.

Here's hoping Ihave a bit more luck putting it back together than I did taking it apart.

Thanks again for your help, I'll let you know if it does the trick.
P.S. I nearly ordered some more blades in case the culprit still turns out to be the Xtreme Blades. Do you have a recommendation similar to the Walkera ones you linked to on ebay for my BOL. Something cheap but a bit more sturdy than stock blades.
P.P.S. You were right about the white Xtreme BOL blades Ibought. Were much more flexible than even the stock blades and lasted barely 5 minutes, with 2 blade strikes. I never had any strikes with the stock ones even, which I'm actually still using. I'll put the walkera ones on when one breaks. I've not replaced the inner shaft yet either - again, I'll try to get most of my crashing out of the way first.

pgroom_68

Hey again mate,

Sounds like you had "fun" disassembling, but rest assured, it does get easier the more you learn about what is what
You've cornered the market on parts I think - it will definitely solve all your problems and fly brilliantly and smoothly![sm=49_49.gif] (fingers crossed)
You asked about cheap harden blades for a L4. - [link=http://www.dealextreme.com/details.dx/sku.20037]THESE[/link] are the answer you seek! They are next in line from Extreme blades in brilliance - suits me fine (I recommend them to you[sm=wink_smile.gif])

One of my birds (pic below) is fitted with DX blades.........[sm=thumbs_up.gif]

Peter[sm=shades_smile.gif]
P.S. That is all the cash you will have to spend on this bird![sm=red_smile.gif]

btm123

I should certainly hope so - I dont think there's much left of the old heli now.

Your Lama looks cool - not much left of original parts on that either, or Esky parts for that matter.

If I break the tail off mine I'll definitely be tempted by the graphite tail boom - looks very good.

Has been too windy here all week for even the BOL so I've really missed the V4. Although I have very little indoor space its fun to mess about practicing landing and putting it where I want. Although it suddenly went very calm last night and I got a couple of great flights with the BOL. I'm finding it much more stable and controllable now.

Will order some of those blades now too, ready for when I need them.

pgroom_68

Hey again mate,

I read on many occasions that the graphite tails are too heavy and adjustments have to be made to the control arms (vertical half-metal-half-plastic arms which go between the swashplate balljoints at the top down to the servo horns at the bottom) so the bird can hover level again. Without this adjustment - many find that this addition makes their heli fly backwards! I bought a [link=http://www.boomtownhobbies.com/BoomTownHobbies_Model_4_Boom_Kit_for_CX2_and_Lama_ p/bth010.htm]Model 4 boom kit[/link] from (appropriately) BoomTownHobbies.com (in the US) - the lightest boom available to date I believe! I highly recommend this over the graphite booms.........[sm=wink_smile.gif]
I have tried to keep to Esky parts on it as much as possible.

Peter[sm=shades_smile.gif]

btm123

Hello again,
I thought you might me pleased (or is the word relieved) that I got this back together again last night and all appears to be well after a quick test flight.
Much smoother.

Ididn't bother using trial and error to work out what part(s) was causing the issue, I just built it with the new parts. I've kept the old stuff as replacements so I'll find out what was good and what was bad if/when I need to call upon them.

I'm pretty sure it was the outer shaft that was the main issue, but that doesn't mean all the other stuff was 100%OK.

Thanks once again for your help. As I said previously it was possibly a good thing that I was forced to strip it down. At least I know how it all fits together now and am confident doing repairs on it.

pgroom_68

Hey again,

An excellent result mate![sm=thumbs_up.gif] I agree that the more you take these birds apart and successfully reassemble them - the better!
We are all asked to be pilots first - but engineers second

Peter[sm=shades_smile.gif]
P.S. I agree the the worst was probably the outer shaft - and the other parts may still be fairly OK.