Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Apr 11, 2008, 07:44 AM
Registered User
Joined May 2006
194 Posts
I was looking at these pics and it looks like this ball was salvaged and drilled out for a screw to attach it? I'm guessing any ball with a stud would work.

-Mark
bigmark61 is offline Find More Posts by bigmark61
Reply With Quote
Sign up now
to remove ads between posts
Old Apr 11, 2008, 09:39 AM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by bigmark61
I was looking at these pics and it looks like this ball was salvaged and drilled out for a screw to attach it? I'm guessing any ball with a stud would work.

-Mark

This ball has a built-in hole in it for a screw to fit in. I actually got it from one of my copterx heli spare parts. You can actually replace this with other ball link options but just make sure the flybar link rod is easily detachable (thus the ball is used instead of the screw) as the flybar usually separates during crashes.
EQMOD is offline Find More Posts by EQMOD
Last edited by EQMOD; Apr 11, 2008 at 09:52 AM.
Reply With Quote
Old Apr 27, 2008, 06:15 PM
Registered User
superevan's Avatar
United States, TX, Austin
Joined Aug 2007
338 Posts
Could use some Help

Hey EQ,
Ive been experimenting with your design on my Lama but Im running into stability problems. I cant for the life of me get it hold a steady hover.
Also when I constructed pitch link for the upper swash I found that the two stabilizing links keep the vertical connection from staying @ 90 degrees so I eliminated them. This works but it seems weak. What am I doing wrong, do you think you could help?
superevan is offline Find More Posts by superevan
Reply With Quote
Old Apr 27, 2008, 09:44 PM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by superevan
Hey EQ,
Ive been experimenting with your design on my Lama but Im running into stability problems. I cant for the life of me get it hold a steady hover.
Also when I constructed pitch link for the upper swash I found that the two stabilizing links keep the vertical connection from staying @ 90 degrees so I eliminated them. This works but it seems weak. What am I doing wrong, do you think you could help?
Looking at the first picture, the upright link (swash to mixing arm) is already out of phase. That upright arm should be close to the blade, in fact 90 degrees is actually under the blade. If the upright arm moves far from this spot you wont get a stable hover.

You need to keep that swash to mixing arm link upright. That means you need the other two links on the swash going to the mixing arm link. If it is not upright, it will go out of phase causing the unstable hover.

The flybar should move freely and when it is horizontal, the blades should be horizontal as well with the pitch equal on both sides.


Also check the blade tracking on the upper blades. Spool it up at half speed and look at the horizontal plane. You should see a single disc, if not, try adjusing (bending) the horizontal arm coming from the swash going to the mixing arm (opposite side of the mixing arm's flybar link). The key is to make it level (for a stable hover) with both upper blades having equal pitch at 0 Aileron and elevator inputs.
EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Apr 27, 2008, 09:55 PM
Heliologist...AMA#899937
BladeCX2Runner's Avatar
Richmond, VA...right next to the Airport...
Joined Jan 2008
2,906 Posts
Quote:
Originally Posted by EQMOD
There is nothing on this thread i mentioned the word "easier".
yea..... its real easy to hit that edit button isnt it???
BladeCX2Runner is offline Find More Posts by BladeCX2Runner
Reply With Quote
Old Apr 27, 2008, 10:04 PM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by BladeCX2Runner
yea..... its real easy to hit that edit button isnt it???
Let me try that again.... Never in this thread i mentioned the word "easier". I see to it what i post is what exactly i experienced. You have read the entire thread posts, I am sure you have not seen that word mentioned here.
EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Apr 27, 2008, 10:09 PM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by BladeCX2Runner
yea..... its real easy to hit that edit button isnt it???

Quote:
Originally Posted by EQMOD
Let me try that again.... Never in this thread i mentioned the word "easier". I see to it what i post is what exactly i experienced. You have read the entire thread posts, I am sure you have not seen that word mentioned here.
While you are at it, you might want to check the other mod projects i've been doing and do some analyzing on the mechanical/physical intrinsics of heli flying;

http://www.rcgroups.com/forums/showthread.php?t=855814
http://www.rcgroups.com/forums/showthread.php?t=852288
EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Apr 27, 2008, 10:54 PM
Registered User
rbinc's Avatar
Californication
Joined Nov 2007
1,234 Posts
Quote:
Originally Posted by EQMOD
Let me try that again.... Never in this thread i mentioned the word "easier". I see to it what i post is what exactly i experienced. You have read the entire thread posts, I am sure you have not seen that word mentioned here.
You aren't entirely honest here:

Quote:
The hover is very much stable (just like the original lama hover feel) except that when you start sending hard aileron and elevator servo movement commands (roll and pitch) the heli moves fast
We both have always known from the beginning that the bold (if we are to tell the truth) is not, and cannot be, the case.

I've applauded your efforts in experimentation, but it's your comments like the above that now have people trying to duplicate what cannot be duplicated.

I believe you are still learning to hover the coaxial helicopter, right?

Regards
rbinc is offline Find More Posts by rbinc
Reply With Quote
Old Apr 27, 2008, 10:55 PM
Registered User
superevan's Avatar
United States, TX, Austin
Joined Aug 2007
338 Posts
Quote:
Originally Posted by EQMOD
Looking at the first picture, the upright link (swash to mixing arm) is already out of phase. That upright arm should be close to the blade, in fact 90 degrees is actually under the blade. If the upright arm moves far from this spot you wont get a stable hover.

Thanks for the help EQ.
Should the upper blade pitch match that of the lower blades exactly? When I spin the heliopter keeping the blades still to check their movement, it looks like the upper blades are hardly changing pitch. When I was test flying today I had a few blade strick crashes which makes me think my mod isnt quite dialed in yet.
superevan is offline Find More Posts by superevan
Reply With Quote
Old Apr 27, 2008, 11:44 PM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by superevan
Thanks for the help EQ.
Should the upper blade pitch match that of the lower blades exactly? When I spin the heliopter keeping the blades still to check their movement, it looks like the upper blades are hardly changing pitch. When I was test flying today I had a few blade strick crashes which makes me think my mod isnt quite dialed in yet.
They are not supposed to match as the upper blades are rotating counterclockwise and the pitching is 90 degrees apart but the net effect would be a combined and synchronized upper and lower blade wind draft putting more aileron/elevator force on the heli.
EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Apr 28, 2008, 12:00 AM
Registered User
superevan's Avatar
United States, TX, Austin
Joined Aug 2007
338 Posts
Quote:
Originally Posted by EQMOD
They are not supposed to match as the upper blades are rotating counterclockwise and the pitching is 90 degrees apart but the net effect would be a combined and synchronized upper and lower blade wind draft putting more aileron/elevator force on the heli.
Thanks again for the info! Oh and whats with all the nay-saying on previous posts? I thought one of the joys of rc was experimentation.
superevan is offline Find More Posts by superevan
Reply With Quote
Old Apr 28, 2008, 01:44 AM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by rbinc
You aren't entirely honest here:



We both have always known from the beginning that the bold (if we are to tell the truth) is not, and cannot be, the case.

I've applauded your efforts in experimentation, but it's your comments like the above that now have people trying to duplicate what cannot be duplicated.

I believe you are still learning to hover the coaxial helicopter, right?

Regards
Here we go again ... oh well ...

Maybe we should re-word what i've said to "Lama hover feel at 0 TX inputs". I've already told you guys that it hovers but when you apply the usual aileron and elevator TX inputs, the heli moves fast. Besides, these coaxials are designed to hover at 0 TX inputs so the the premise still apply. But when you start providing those aileron and elevator inputs, the mod will act differently from the stock one as the upper blades are now contributing to the aileron and elevator commands.

I think the modded heli is hovering on this video right ? It may just need some trimming but it does hover...

Lama V4 Double Swashplate mod - Outdoor Hover Tests (1 min 14 sec)



Also, I am way past the "learning to hover" process, and my hovering skills does not in a way restricted to just to coaxials.

Here is one funky little hover on a very tight space on a modded experimental CP2. Video of the hover starts at 1:09.

HoneyBee CP2 Brushless Direct Drive Tail with Tail Servo (4 min 11 sec)


Take note of the tail, its a brushless motor with a tail servo.
EQMOD is offline Find More Posts by EQMOD
Last edited by EQMOD; Apr 28, 2008 at 01:56 AM.
Reply With Quote
Old Apr 28, 2008, 05:38 PM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
bigmark61 has came out a better design on the swash to upper blade link using a v-link configuration. Its tight and clean;

EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Apr 28, 2008, 06:58 PM
Registered User
rbinc's Avatar
Californication
Joined Nov 2007
1,234 Posts
Quote:
Originally Posted by EQMOD
Here we go again ... oh well ...

Maybe we should re-word what i've said to "Lama hover feel at 0 TX inputs". I've already told you guys that it hovers but when you apply the usual aileron and elevator TX inputs, the heli moves fast. Besides, these coaxials are designed to hover at 0 TX inputs so the the premise still apply. But when you start providing those aileron and elevator inputs, the mod will act differently from the stock one as the upper blades are now contributing to the aileron and elevator commands.

I think the modded heli is hovering on this video right ? It may just need some trimming but it does hover...

Also, I am way past the "learning to hover" process, and my hovering skills does not in a way restricted to just to coaxials.

Here is one funky little hover on a very tight space on a modded experimental CP2. Video of the hover starts at 1:09.

Take note of the tail, its a brushless motor with a tail servo.
Yes, it is quite tiresome, but we will eventually get to the bottom of it.

In your video (as I have pointed out time and again), you are countering cyclic to bring the helicopter back into a hover and then releasing the stick. Exactly in the same fashion as we stabilize any single rotor helicopter back into a hover. This IS NOT how any stock FP coaxial performs; all that is required is to release cyclic and the helicopter will hover as well as it is trimmed. Your climb outs are also very similar to a single rotor with non-commanded cyclic; I can do the same with a CP Pro in no wind. Once I command cyclic, I massage back to a hover the same way you do in the video.

Over and over, you miss my point. I'm NOT knocking (or "naysaying) your modifications; I think they are quite clever and applaud you (again) for the creativity. The point is that I and others have done exactly the same thing and, while we have experienced performance improvement, it is AT THE EXPENSE of the stability of the coaxial as it comes from the factory. That is ALL I am saying.

You seem to understand the physics of helicopters well enough, so you should be able to admit that ANY inhibition of a free upper rotor and flybar gyro HAS to compromise the stability of the original design. You link this to ANYTHING and it has a negative effect. Can we agree on this? If not, you need to post a video showing that your helicopter returns to THE SAME STABLE hover as a stock Lama simply by releasing the cyclic, regardless of swash deflection prior to release.

The comment about hovering was from this:

Quote:
Still practicing. I may have to work on the throttle stick "click stops" Ratchet plate. With a fresh charge of the Lipo, one click above drives the heli higher, one tx throttle "click" below moves the heli lower. There is no "in-between". In this case, i had to move the throttle stick alternately up and down in between clicks for a steady hover. Plus the fact that the gyro switch is above the throttle switch that i sometimes had to release my thumb on the throttle to flick the switch.
From this thread:

http://www.rcgroups.com/forums/showt...t=servo+gunner

In your video, you never had the helicopter in a stable hover, even if it was your learning to manage the throttle stick's ratchet. I can hover a stock Lama perfectly well (especially indoors) with the stock TX, regardless of the TX's ratchet

Here's the bottom line IMO:

I think you are a talented and creative individual that is clearly having a ball with the hobby. I'm happy for you. Your modifications have been tried over and over again and they result in a departure from stability of the original helicopter. At this point, one usually moves on to a real helicopter and retains the stock coaxial precisely for the tame stability it affords in casual indoor flight.

But your modifications need to explain the sacrifices and negative effects as WELL as the positive. Coaxial helicopters, as they come from the factory, are tremendous learning tools for a hundred bucks or so. Many of your posts suggest that the beginner can modify their coaxial and get outstanding performance WITH NO SACRIFICE. This IS NOT the case.

All my point has ever been. Continue experimenting. It would just be nice, IMO, to see an honest evaluation of the results.

By the way, what is the point of the tail motor on the CP2? You've introduced complexity and failure potential beyond the simple belt drive and likely had some considerable CG issues to compensate for? Not "Naysaying", but why?

Regards
rbinc is offline Find More Posts by rbinc
Reply With Quote
Old Apr 28, 2008, 09:04 PM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by rbinc
Yes, it is quite tiresome, but we will eventually get to the bottom of it.

In your video (as I have pointed out time and again), you are countering cyclic to bring the helicopter back into a hover and then releasing the stick. Exactly in the same fashion as we stabilize any single rotor helicopter back into a hover. This IS NOT how any stock FP coaxial performs; all that is required is to release cyclic and the helicopter will hover as well as it is trimmed. Your climb outs are also very similar to a single rotor with non-commanded cyclic; I can do the same with a CP Pro in no wind. Once I command cyclic, I massage back to a hover the same way you do in the video.
Maybe a good video from you showing "0" TX inputs would give a definition of a good hover on a stock coaxial. Probably that would clear things out as i see we have different views of what a "0" TX input hover really like from a coaxial stock.

Quote:
Originally Posted by rbinc
In your video, you never had the helicopter in a stable hover, even if it was your learning to manage the throttle stick's ratchet. I can hover a stock Lama perfectly well (especially indoors) with the stock TX, regardless of the TX's ratchet
This is a completely different issue and is not in any way related to aileron/elevator/flybar stability or the dual swash mod. As i have said, i only encounter this from a fully charged state lipo where the motors are still rotating quite fast that that i had to play around with the throttle stick ratchet clicks for a stable heli height. But when the Lipo's juice is just mid-way, the throttle control is stable.


Quote:
Originally Posted by rbinc
All my point has ever been. Continue experimenting. It would just be nice, IMO, to see an honest evaluation of the results.
I already did my best in pointing out what the mod results are. If there is something - probably technical in nature you would like to see such as results at certain TX settings, i would be glad to test and post the results. As far as i am concerned, i already provided the details based on my experience on this mod.


Quote:
Originally Posted by rbinc
By the way, what is the point of the tail motor on the CP2? You've introduced complexity and failure potential beyond the simple belt drive and likely had some considerable CG issues to compensate for? Not "Naysaying", but why?
The HoneyBee CP2 right out of the box is not a belt drive heli. The CP2's carbon fiber tail will never become a belt drive. I guess you have already tried flying a brush motor tail driven heli and have had experienced the ill negative effects of a direct drive brush tail motor right ? I think you also know what the advantages of having a tail servo + blade pitch changes in controlling the heli's tail as against "motor speed" dependent rudder control. As such, how do you now combine a non-belt drive, tail servo + gyro driven, tail blade pitch control on a heli such as the Honeybee CP2 ? Thus this mod ....
EQMOD is offline Find More Posts by EQMOD
Last edited by EQMOD; Apr 28, 2008 at 09:23 PM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion LAMA V4 Double Pitch Control Mod EQMOD Micro Helis 5 May 23, 2008 06:07 PM
Contest Lama V4 mod contest dubhouse11 Coaxial Helicopters 0 Mar 05, 2008 09:50 PM
Discussion Ka-50 Project for Lama V4, oh yeah!! Drew816 Coaxial Helicopters 13 Feb 23, 2008 11:19 AM
Discussion Lama V4 swashplate stock bearing removal? Drew816 Coaxial Helicopters 0 Feb 01, 2008 11:57 AM
Mini-HowTo Lama Swashplate Mod Lou Coaxial Helicopters 3 Feb 08, 2007 05:45 AM