Batty33Res

Is longer servo arms the only way to get any real forward or backwards flight? On mine, you can push the cyclic full forwards or backwardsand it will go forwards or backwards a few feet then stop, Any forward or backwards flight is SO WEAK its unreal. My comanche is stock except Xtreme blades and shortened 3" flybar.

pgroom_68

Hey again mate,

As far as I know you are entirely correct! The swashplate tilts in a direction in order for the bird to fly off in that direction - the more tilt the greater the action! The only way to increase this tilting is to increase the servo "throw". Caution must be used in adjusting servo arms on the servo (the spline is the first tricky parts) - to allow both forward & reverse servo throw of the same distance!!

Are the white [link=http://www.rc711.com/shop/esky-7g-servo-horns-and-screw-set-p-1903.html]servo arms[/link] in the commache full-length or have they been trimmed after the first hole[:@] (like the Lama4)??

Peter[sm=shades_smile.gif]
P.S. You might get more answers if you post within the [link=http://www.rcuniverse.com/forum/m_7311577/mpage_138/tm.htm]ESKY LAMA 4 THREAD[/link] coaxial thread.[sm=49_49.gif] I don't see a problem with doing this - 'cause most of the Esky small coaxs are basically the same (and some fliers have more than one model eg. Lama4, Lama3 & Hunter)[sm=thumbs_up.gif]

Batty33Res

Yes they have been trimmed after the first hole on the servo arms. Chopper seems to fly sideways better than forwards backwards or atleast it seems to have more movememt side to side. Guess I just need to get longer servo arms and a longer inner shaft.

btm123

I'd also be interested to know what the options are with this. My Big Lama also struggles a bit with forward flight, especially if there is a light breeze. It sets off OK, then appears to hit a brick wall and tilts backwards, even on full forward. I know it is a different heli, but very similar underneath.

At the moment I'm very new to this so I'm happy to get more practice as it is, but in the near future I'd like to make it a little more responsive/faster going forwards so I can battle against the wind a bit better. In my case I'm consious about not running before I can walk though : )

I also need my forward trim on full in order to balance for hover, so think Imay have some room to adjust on mine anyway.

This youtube vid has a battery mod for the big lama as he was suffering the same thing - faster backwards than forwards - perhaps you can do something similar on your comanche?

http://www.youtube.com/watch?v=yMctPc_Dq2g

I also have an extra hole at the end of my servo arm for forward/backwards, so Imay try extending it out one. I assume I can move the forward back one out without having to move out the left/right one, or do they need to be moved together? (the left/right one has been cut off)

Does extending the existing arms (i.e. by unscrewing them a couple of turns) increase the throw, or does that not work?

Batty33Res - hope I've not hijacked your thread too much. I believe all this stuff is equally relevent on Lama, Comanche and BOL

Batty33Res

Thanks BTM123 your simptoms are same as mine, starts off flying forwards, then kinda stalls out after several feet even when holding the cyclic full forwards then kinds lunges backwards? Glad to know I'm not the only one with this problem. Hopefully someone can help us with this problem

btm123

I think mine is related to the breeze rather than a problem. Ishould have said this is normally noticable going in one direction, but coming back the other direction is much better.

I dont think its an issue as such, it just needs a bit more power to beat the breeze sometimes. As I said it is super stable, which suits me now whilst in learner mode, but I am starting to think I could do with a little more forward power now.

Are you using yours indoors our outdoors?

Batty33Res

I fly mine indoors and outdoors, past 2 days we have had zero wind. Not even the smallest breeze so it's been nice being able to go outside and fly it. Like you said though, mine hovers great and even launches forwards good for the first few feet but then it just kinda slows to a hault, even with me holding the cyclic full forwards.

btm123

I'm still not 100% sure what the best way to improve this is, as I'm not 100%sure what the cause of the issue is.
From what I've seen the options are:
1. Move servo links out on plastic bars if there is another hole to move to, to give more throw
2. Unscrew and hence lengthen the servo arms to give more throw
3. An adjustable/shorter flybar will give better performance, which may or may stop the helis slowing down.
4. Add some weight to the nose, or preferably move some weight (battery) to keep the nose down a bit.

I've very new to this, but from what I've read and seen I get the impression these are setup at the factory to be as stable as possible in hover. Its just a question of the best way to 'unstabilise' them.

Hopefully we'll get some advice - if not I'll post in the BOL forums in a week or two as I was going to before I saw your post.

pgroom_68

Hey again guys,

Sorry. I've just come out of hospital after an operation and I couldn't sit for extended periods before.

I will try to answer both of your queries at once - i hope you don't mind!

The phenomenon of suddenly stopping forward flight you are both experiencing (we try to reserve "stalling" for a sudden loss of blade rpm ) is due to the flybar authority taking over your forward input with the right stick (cyclic). I will try to explain it thus: The flybar "flies" the upper rotors (trying to keep them horizontal to the ground so your bird hovers) while you fly the bottom rotors. When the flybar authority is stronger than the swashplate tilting input from your Tx, the flybar "takes over" bringing the bird back to hover![sm=49_49.gif] To get around this happening you have to achieve a couple of major things. As btm123 says, you give the bird more servo throw - thus allowing the swashplate to tilt further; and lower the flybar authority by a combination of lowering the weights at its ends and/or shortening the distance from the hub at which it spins. Flybar torque is not your enemy though! If you lower and/or move the weight towards the hub too much - disaster!![sm=confused_smile.gif] Results: "head stall" & "death slide" - not good[:@]

Btm123 above also suggested unscrewing the servo arm and moving it. It is not that easy - sorry - 'cause as you rotate the servo arm in one direction (beware the spline[sm=wink_smile.gif]) it also shortens the amount of throw in the opposite direction......but there is room on some birds for a little adjustment to even up the throw distances - just remember that the spline usually doesn't allow you to place it exactly where you want..........!

Adding weight to the nose is never a good idea 'cause these birds are very light and adding any extra weight may not allow your bird to get enough lift to take off.......[&:] A much better option if sliding the lipo forward (and then hold in place with rubber bands) to move the center of gravity (CG). This will give less stability in hover - but allow longer forward flight.

Peter[sm=shades_smile.gif]
P.S. [link=http://www.helitek-rc.com/index.php?act=viewProd&productId=60]HERE[/link] is a link to adjustable flybar weights which are able to be slipped onto (and tightened) your existing flybar - you obviously have to cut off the black plastic-encased stock weights first. Email HeliTek-rc (via their "contact us") and ask questions..........[sm=regular_smile.gif]
P.P.S. This is a coax only phenomonen. I hope that clears up a few things........................[sm=teeth_smile.gif]

btm123

Thanks once again Peter,
That totally makes sense now. I'll see if I can source some of those weights nearer to home. Do the ones you linked to fit a BOL or just a V4. I'm going to leave my V4 alone as its just for around the house, so the more stable the better. Its the BOL Ineed a bit more forward thrust on.

If not is there a shorter/adjustable replacement Ican try? Or is it just trial and error to get a decent fit.
Also, is there a knack to ensure the weights end up the same distance apart so as not to indroduce vibration?

Hope you are feeling better soon. Apologies for bombarding you with questions when you are feeling under the weather.

erdnuckel2

Hi btm,

even if I am not Peter ... the weights from his link will NOT work for a BOL(without modification ... you would need 2 Sets and drill the holes out, as the diameter of the BOL flybar is larger than that of the LamaV4)
However, helitek sells an adjustable flybar for the BOL through eBay ...
http://cgi.ebay.com/L-K-NEW-Adjustab...item3f0149be34

or you could get the weights alone (brass weights either 8.8g or 12.6g ... same price ...) made by Skytec (if you interested contact leethetreeguy at www.coaxsupermodspartsshop.com)

hth

Edit:
just saw you are in the UK ... you might be able to get the Skytec weights easier at www.helischrauber.de

pgroom_68

Hey again & thanks Sven,

I am too sore to sit for a long time at keyboard.......[sm=thumbs_up.gif]

Peter[sm=shades_smile.gif]
P.S. The linked helitek-rc adjustable flybar is the better option IMO. Just remove the weights from it when it arrives. Cut off the stock weights near the black plastic and replace just the weights from the helitek-rc.com one! A dob of solder on the ends of the flybar after you have slipped on the weights will stop them coming off again in flight

btm123

Thanks Both,
I've ordered a heliteck one. The time it takes for delivery is not an issue, I can still use a lot of practice whilst it is fully stable.

I'm curious why you suggest cutting off and using the weights - why not just use the Helitek flybar when it arrives? Or are you referring to future if it gets damaged.

Rereading Peter's excellent description above, could you explain one further thing to me. Th coax helis with the flybars are pretty much designed to always return to a horizontal and stable hover. What technique should be used for banked turns with coaxs, or should turns just be done using the rudder without banking?

So far I'm using just the rudder for turns, but was going to go to a bigger area to practice higher speed and larger banked turns, as I've read in various tutorials. The implication is that the cyclic is used to bank, in the same was as with an aeroplane, but the guides I've found are mainly for CP helis. I'm starting to think (and I've tried in limited space) that the BOL doesn't need to be banked when turning, and in fact will try to turn against the bank anyway.

I'm not sure I've explained that question very well, but hopefully you get the idea.

Batty33Res - sorry, despite apologising for doing so originally, I do now appear to have completely hijacked your post. I hope all this stuff is useful to you also.

pgroom_68

Hey again guys,
(I assume both of you are reading along....[sm=49_49.gif])
I suggested cutting off the original weights and using the Helitek flybar weights in their place, due to the fact that the black plastic "seesaw" of the Helitek hub is slightly larger and may bind on the cap or the screws that hold the cap in place. To totally avoid this happening, just leave the actual flybar on and cut off the "black-encased" stock weights - if it ain't broke - don't "fix" it!
Alternatively you can file the Helitek's circular "seesaw" hub down to the same size as a stock flybar's hub - but that is just a pain![sm=confused_smile.gif]

Re. banking turns - they are better done with a higher head speed CP as it can handle the strains, but are able to be performed with a coax very carefully but only in FFF! [link=http://www.rcuniverse.com/forum/fb.asp?m=8382165]HERE[/link] is a link to the info needed to perform - 1. try at your own risk. 2. PM shadow99 for more details.
To view a video of Simon's where he performs 45º banks - [link=http://www.youtube.com/watch?v=BnyU6wKgnWU&feature=player_embedded]HERE[/link] is his YouTube video!

Peter[sm=shades_smile.gif]

btm123

OK, I'll have a look at it when it turns up.

Not sure what other mods Simon has done but his Lama flys very well with the adjustablle flybar, though I'm clearly a long way off his skill level. I'll be bringing those weights in very slowly but surely. Very impressive stuff though.

pgroom_68

Hey again btm123,

Simon has years of experience now - and even owns and flies (hovers) a 450 Trex clone - so his journey is roughly around halfway![sm=72_72.gif] The adjustable flybar can lower the flybar authority and the servo arms are full length on the BOL, so the only other variable is the blade "stiffness". You see you don't want coning to create a blade strike for you. (You want that "priviledge" yourself[sm=wink_smile.gif])

The blades I have tried from "stiffest" to "bendiest" are:
Extreme [link=http://www.miracle-mart.com/store/index.php?main_page=product_info&cPath=80_204_212&products_id=3398]'blues'[/link] (you will need to purchase both uppers & lowers - so be prepared to double that $), Walkera Lama [link=http://www.miracle-mart.com/store/index.php?main_page=product_info&cPath=80_203_224&products_id=3105]400Ds[/link] - trimmed (the ones that both Simon & I prefer), [link=http://www.miracle-mart.com/store/index.php?main_page=product_info&products_id=2824]stock Esky[/link], HighPrecisionRotor blades (HPR blades), Extreme '[link=http://www.miracle-mart.com/store/index.php?main_page=product_info&cPath=80_204_212&products_id=3412]whites[/link]' (these are only good for onboard cam work IMO)

The HPR blades were readily available (and really cheap) before now, and could be taped with a layer of clear parcel tape on the lower - then the upper surface from root to tip (then trimmed) to make them a lot stiffer - and much more suitable to BOL flying! I just searched for them on ebay again - and turned up nothing.........

I haven't tried the Extreme '[link=http://www.miracle-mart.com/store/index.php?main_page=product_info&cPath=80_204_212&products_id=4323]blackies[/link]' to see if they are what I am searching for!

Peter[sm=shades_smile.gif]
P.S. While linking info for you, I came across [link=http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=400106329088#ht_2696wt_1054]THESE[/link] blades also[sm=confused.gif] I have ordered a couple of sets - so I will edit and insert detail later.......
P.P.S. Be very careful when moving the weights inwards towards the hub - 'cause (after about 2 inches of movement when there seems to be no diff.) suddenly the slightest change (of 2mm) will cause a huge diff to hover stability!! Also a great tip is to apply a dob of solder to the ends of the flybar after you have slipped on the adjustable weights. This ensures that they can't spin off at high rpm should the hex screws not hold[sm=49_49.gif]

erdnuckel2

Even though I have not flown the fake CF xtremes, Ihave a pair at home and Ican tell you they bend as bad as the white ones do! So it is to expect that they will not be a preferred choice for "sporty" flying, Peter ...

take care
Sven

pgroom_68

...Thanks Sven![sm=49_49.gif] I had assumed so - but am still unwilling to fork out the $ to try them[sm=regular_smile.gif]

Peter[sm=shades_smile.gif]
P.S. The [link=http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=400106329088#ht_2696wt_1054]Eagle3[/link] blades arrived in today's mail - so I will be trying those out soon....! As the pic shows the hole in the root is huge - but that shouldn't make much diff. to the mounting, but what will make a diff., is the thickness of the root within the blade-grips. I will be taking a flat file to these (and perhaps some plastic spacers/fillers to go in the holes The rubber on the leading edge definitely makes them stiffer!!

btm123

Hi again,
Still waiting for the adjustable flybar for now, which isn't a bad thing as I can get a bit more practice.

I've been looking again at adjusting the forward flights on mine again in the meanwhile. I know it sounds like I'm going round in circles but it really is quicker going backwards than forwards. On top of that for hover I need it trimmed as far forward as possible to stay still.

So it must be possible to adjust this, yes?

I've tried moving the battery forward and that does make it better forwards and I can move the trim back nearer the centre. Thats one solution if Ican get a way to hold the battery it in place.

But, surely this is not the best way. Can I not just adjust the upper servo arm to make it longer? I tried that (unscrewed one full turn initially then 2 full turns) and it seems to make the heli quite unstable, and veers to the side.
Why is this - I've checked I'm lengthening the correct rod by moving the trim. The rod I extended was the back left one when looking from the rear, that moves the swashplate. I can see it moving if I move the stick forwards.

There are also two adjustables from the swashplate to the blade holder. Should I need to do anything with them.

I know the way to get more throw is with longer servo horns (is that the right term?) and I dont want to do that, just balance the forward/backwards sweetspot so Idont have to be trimming fully forwards.

Can this be done or am I better off just moving the battery as I've already worked out improves things?

I figure I'm better trying to get it balanced as it is now rather than trying to balance it after I reduce the flybar.
P.S. Funny thing happened yesterday, I was practicing landing on a low stone wall in the garden. Just as I landed a quite large frog jumped out straight into the underneath of the BOL, and got itself wedged facing forwards looking out of the front window. Didn't manage to get a photo sadly as he didn't really feel like staying in there too long. For all the animal lovers out there I refrained from taking it for a test flight.
P.P.S. Peter, hope you are now feeling better and are getting back to flying

pgroom_68

Hey again mate,

[link=http://www.rcuniverse.com/forum/fb.asp?m=8876563]HERE[/link] are the linkage adjustments that you are trying. What you are experiencing is due to a couple of very complex physics propositions. I will spare you the details - simply (maybe "over-simply"): Notice when you move the stick forward and backwards the swashplate doesn't tilt exactly towards the front and rear? (Similar with left & right stick movements - the swashplate tilts at a "combination" of sideways and forwards). By the time (a milli-milli-second) the blades have elicited the desired response from your bird in the air - the blades have tracked to the correct positions. If you are really keen look up " dihedral of lift " & " blade progession in rotary flight "[X(]

To answer your questions - sorry, unless I see your coax bird and can adjust the control links (vertical half-plastic/half-metal links) myself, I really can't offer any suggestions apart from ordering full-length servo horns - you can install just one (on the elevator servo). This would give you greater forward movement - then you could balance the CG with the lipo![sm=thumbs_up.gif]

Yip - feeling 98% now and back at work[:@] Weather here is the only thing stopping me from flying outdoors (winter here ATM) My next indoor helimeet is due next Tuesday - but from initial tests here in the house, I have lost the "touch" (or is that the "feel") - still it shouldn't be hard to get it back!! I am having fun in Clearview - but a sim can only do so much..............

Peter[sm=shades_smile.gif]
P.S. What do you mean by "two adjustables from the swashplate to the blade holder. Should I need to do anything with them". My small coax' just have black plastic non-adjustable vertical linkages here (you can see one of them in linked pic)[sm=49_49.gif]

btm123

Thanks Peter,
At least I'm not going mad. I couldn't work out for the life of me why it was going to one side.
If it isn't that simple I think I'll leave well alone and try to pull the battery forward instead. The adjustable flybar is here now so can get that on too.

Sadly its too windy to do anything much at the moment.

For my curiousity, why is getting longer servo horns any different to just lengthening the push rod? Is it not the same, especially if I only replaced the one servo horn. As I said its mainly out of curiousity as I dont think I want to risk adjusting this into being unstable.

P.S. to answer your question on my BOL I have adjustable link rods from the servo horns to the bottom of the swashplate. Then from the top of the swashplate the arms that push up and connect to the bottom blade grip also look to be adjustable, though I'm not sure why you'd want to. On the pic on the link you attached they are fixed length - you can see the one at the front as you look at the pic.

btm123

Well, the wind suddenly dropped so I've been out with the adjustable flybar.
It certainly livens things up a bit

I've tried 3 settings so far.
First was 32mm in from the ends of the helitek bar. Was quicker but still suffered from the difficulty maintaining forward flight.
I then went straight to a credit card width, which was too much for me.
Finally ended up with 45mm, which was probably still too twitchy for me, but gave fast flight.

HOWEVER.......... in all cases it kept rocking forward and backwards. It didn't appear to be going left to right at all, just forwards and backwards. So I could set off at pace forwards, it would go faster/further than usual, but then still rock right backwards. Even trying to hover it was constantly rocking back and forth. Not just moving back and forth, it was rocking like a seasaw.

So it looks like the lower weight is amplifying the issues I have with going forward, and actually making it worse. Unless I'm just not ready skills-wize yet for the lack of flybar authority.

I know its very difficult without seeing it but any idea what to do next. I guess I need to get the batteries weighted forwards and try to resolve the balance that way, and then try again? Or does it sound like I need to persevere with changing the flybar weights?

Edit:
I guess what I'm trying to say is my original problem at the start of the thread was that the heli was going forwards then tilting backwards and stopping. That was put down to too much flybar authority. However, now I've reduced it I've made it worse. Although it flys faster and further forwards, when the flybar pulls it back it is much more severe. OR - is the problem not really the flybar authority and more to do with the balance issue whereby it flys better backwards than forwards. I'm a bit confused now. Or, maybe I'm just not up to flying with the lower flybar authority yet of course

pgroom_68

Hey again BTM,

I think you misunderstand the flybar authority. The problem wouldn't be solved by an adjustable flybar alone. What it sounds like to me is your center of gravity (CG - you call it balance) - the pivot point is too far toward the front of the bird. Move the lipo forward and use rubber bands to hold it still. This affectively moves the heaviest point to under the axis. This will allow you to fly forwards indefinitely now that you have "mastered" the flybar weight distance that you are happy with.....

Enjoy.

Peter[sm=shades_smile.gif]
P.S. Brendon (stalyoni) has this set up on his Lama4 and loves it! [link=http://www.rcuniverse.com/forum/fb.asp?m=9511339]HERE[/link] is his post with videos - I hope he doesn't mind[sm=red_smile.gif]