HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Mar 24, 2008, 05:42 AM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Discussion
Lama V4 Double Pitch Control / Tail Rotor / Single direction coaxial Mod

I modified my Lama V4 in order to improve its flight responsiveness;






Modifications:

Single Brushless motor (upper and lower blades both rotating in one direction)
Tail Rotor with Gyro
Dual ESC configuration
Double Pitch Control with upper blades linked to the swash plate via mixing arm

Mod Pictures:

Sinlge Brushless motor for Both upper and lower blades (both rotating in one direction)



Both gears strapped together and are being rotated by a single brushless motor pinion;






Added a gyro controlled tail rotor;




Double Pitch Control - Both upper and lower blades provide pitch data coming from the swashplate improving flight response;




Videos:
Demo of the Lama V4 mod with hard/extreme aileron / elevator / throttle commands to show responsiveness. Take note; No blade strikes or turboshaft modification. Blades are hardened though.
Crazy Lama V4 flying w/ tail rotor/double pitch control mod (0 min 44 sec)


Indoor Hover Tests:
Lama V4 Tail Rotor / double pitch mod indoor hover test (0 min 49 sec)


Demo of Upper Blade Pitch control:
Lama V4 Double Pitch control mod (0 min 38 sec)


Demof of the blades in action showing transmission of pitch data from swashplate to the upper blades
Lama V4 Double Pitch control mod Blade tracking demo (0 min 27 sec)
EQMOD is offline Find More Posts by EQMOD
Last edited by EQMOD; Sep 12, 2008 at 01:36 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 24, 2008, 06:20 AM
Registered User
Joined Jan 2005
226 Posts
wooooooow, very nice!
jazzy is offline Find More Posts by jazzy
Reply With Quote
Old Mar 24, 2008, 06:26 AM
Suspended Account
Pittsburgh PA
Joined Dec 2004
2,365 Posts
nifty project,

what benefit does it have over a single rotor?

does the flybar even need to be installed now that the upper rotor is linked to the swash?
Cable Guy is offline Find More Posts by Cable Guy
Reply With Quote  (Disabled)
Old Mar 24, 2008, 06:44 AM
Registered User
Joined Jan 2005
226 Posts
Does it handle like a single rotor?
jazzy is offline Find More Posts by jazzy
Reply With Quote
Old Mar 24, 2008, 08:23 AM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by Cable Guy
nifty project,

what benefit does it have over a single rotor?

does the flybar even need to be installed now that the upper rotor is linked to the swash?
In this case we get to use a single brushless motor on all four blades.
With four blades, you achieve lift on a smaller diameter blade footprint (which all coaxial lamas have) as against a two bladed heli with a wider diameter.

The flybar is still needed for stability (same function as the ccpm paddles).
EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Mar 24, 2008, 08:28 AM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by jazzy
Does it handle like a single rotor?
Handling is like a single rotor specially if you link the upper blades to the swashplate.

On a standard lama v4 coaxial implementation, the upper blades only contribute to lift and stability plus the anti-torque for the lower blades. The lower blades contribute to the heli's lift and direction.

In this mod, both the lower and upper blades contribute to stability, lift, and direction. Anti-torque is provided by the gyro controlled tail rotor. With all four blades contributing to lift and direction (pitch and roll), heli's directional response is greatly improved.
EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Mar 28, 2008, 04:24 PM
Registered User
in the middle, somewhere...
Joined Jun 2007
199 Posts
very interesting....

Curious why not have upper and lower blades at 90 degrees from each other, to separate the down wash a bit.

It would be interesting to see something like this cut to a much lower mast height, with a single four-blade, or closely double-stacked 90-degree head assembly.

Or even a mid-mount flybar-link assembly, between upper and lower 2-blade heads... and on a single driveshaft. (could ditch the inner shaft altogether)

I like the multiple-blade makes for a smaller rotor circle fixed pitch heli concept.

I wonder if anyone makes a 4-rotor head for modest size fixed-pitch helis that could use lama-style blades in the grips...
CanardianFan is offline Find More Posts by CanardianFan
Reply With Quote
Old Apr 01, 2008, 12:06 AM
Registered User
Joined Apr 2007
320 Posts
Hmmm Nice work. But it seems pretty unstable. More like a FP now.
altronpower is offline Find More Posts by altronpower
Reply With Quote
Old Apr 01, 2008, 07:02 PM
Registered User
rbinc's Avatar
Californication
Joined Nov 2007
1,234 Posts
Quote:
Originally Posted by CanardianFan
very interesting....

Curious why not have upper and lower blades at 90 degrees from each other, to separate the down wash a bit.

It would be interesting to see something like this cut to a much lower mast height, with a single four-blade, or closely double-stacked 90-degree head assembly.

Or even a mid-mount flybar-link assembly, between upper and lower 2-blade heads... and on a single driveshaft. (could ditch the inner shaft altogether)

I like the multiple-blade makes for a smaller rotor circle fixed pitch heli concept.

I wonder if anyone makes a 4-rotor head for modest size fixed-pitch helis that could use lama-style blades in the grips...
Because locking upper and lower FP rotors together at 90 degrees would result in a helicopter that could not be flown without some complicated additional flybar/paddle mixing (perhaps TWO flybars with paddles) and the advance or retard (depending on rotation of the fixed head) of servo positions to compensate precession.

I give the guy kudos for experimentation, but it's a road very well traveled. One cannot modify the simple physics of this helicopter and expect the same results. It's either a simple heli intended for indoor flight that nearly anyone can master, or it's a step toward a real helicopter that is much harder to control. If the latter, why not buy a real helicopter?


Regards
rbinc is offline Find More Posts by rbinc
Reply With Quote
Old Apr 01, 2008, 07:03 PM
Registered User
rbinc's Avatar
Californication
Joined Nov 2007
1,234 Posts
Quote:
Originally Posted by altronpower
Hmmm Nice work. But it seems pretty unstable. More like a FP now.

Precisely.

Regards
rbinc is offline Find More Posts by rbinc
Reply With Quote
Old Apr 01, 2008, 07:29 PM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by rbinc
Because locking upper and lower FP rotors together at 90 degrees would result in a helicopter that could not be flown without some complicated additional flybar/paddle mixing (perhaps TWO flybars with paddles) and the advance or retard (depending on rotation of the fixed head) of servo positions to compensate precession.

I give the guy kudos for experimentation, but it's a road very well traveled. One cannot modify the simple physics of this helicopter and expect the same results. It's either a simple heli intended for indoor flight that nearly anyone can master, or it's a step toward a real helicopter that is much harder to control. If the latter, why not buy a real helicopter?


Regards
I guess you are the guy who hates creativity and exploratory test and heavily rely what the commercial vendors present - "that is if you want something new... simply buy them". These projects are meant to be interpreted as experimental at as it shows different possibilities on different configurations. The important thing is, it is flying and it is controllable. Now as to the type of control feel you are aiming for, that is a different story. In this case, its a presentation of how one can convert a coaxial configuration to a "FP" like flyer. Obviously, this experiment is not here to retain the original Lama feel as it is not anymore coaxial and it has its own tail rotor
EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Apr 01, 2008, 07:43 PM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by rbinc
Because locking upper and lower FP rotors together at 90 degrees would result in a helicopter that could not be flown without some complicated additional flybar/paddle mixing (perhaps TWO flybars with paddles) and the advance or retard (depending on rotation of the fixed head) of servo positions to compensate precession.
No need to those complicated flybar/paddled/or dual flybars. If you want a 90 degree configuration, there are two simple ways to do it;

1. remove the pitch link going to the upper blades and simply use the upper blades as a flybar stabilized lift control blades and the let the two lower blades handle the direction.

2. Mount the pitch link of the upper blades directly to the swashplate and the mount point should be 90 degrees from the mount point of the two pitch links intended for the lower blades.
EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Apr 01, 2008, 07:49 PM
Registered User
rbinc's Avatar
Californication
Joined Nov 2007
1,234 Posts
Quote:
Originally Posted by EQMOD
I guess you are the guy who hates creativity and exploratory test and heavily rely what the commercial vendors present - "that is if you want something new... simply buy them". These projects are meant to be interpreted as experimental at as it shows different possibilities on different configurations. The important thing is, it is flying and it is controllable. Now as to the type of control feel you are aiming for, that is a different story. In this case, its a presentation of how one can convert a coaxial configuration to a "FP" like flyer.
Read this again:

Quote:
I give the guy kudos for experimentation, but it's a road very well traveled. One cannot modify the simple physics of this helicopter and expect the same results. It's either a simple heli intended for indoor flight that nearly anyone can master, or it's a step toward a real helicopter that is much harder to control. If the latter, why not buy a real helicopter?
Not knocking your experiments, as I've told you time and again.

But, there is no rational reason to convert a counter-rotating coaxial to single-rotor FP flight characteristics. All simplicity and ease is lost once one does. I know you think you are after something new and improved, but it cannot be done with this platform AND REMAIN the stable and easy to fly helicopter that it is. The physics will not change.

It is flying and controllable, but not in the same fashion as factory configuration.

Hundreds of people read this forum every day. Many are new pilots just learning how helicopters work and how to fly them. It is egregious to suggest that your experiments are an improvement (in your words) over what they just payed hard-earned cash for. Few will have the bin of components that you have assembled and tweaked to get flying. Fewer will have your knowledge of how to make it all work. This is the "Multi-Rotor" forum and such is largely for people with counter-rotating coaxial helicopters.

We either engage in truth-telling here or we are wasting everyone's time.

Best Regards
rbinc is offline Find More Posts by rbinc
Reply With Quote
Old Apr 01, 2008, 07:59 PM
Registered User
EQMOD's Avatar
Joined Mar 2008
3,775 Posts
Quote:
Originally Posted by rbinc
Read this again:



Not knocking your experiments, as I've told you time and again.

But, there is no rational reason to convert a counter-rotating coaxial to single-rotor FP flight characteristics. All simplicity and ease is lost once one does. I know you think you are after something new and improved, but it cannot be done with this platform AND REMAIN the stable and easy to fly helicopter that it is. The physics will not change.

It is flying and controllable, but not in the same fashion as factory configuration.

Hundreds of people read this forum every day. Many are new pilots just learning how helicopters work and how to fly them. It is egregious to suggest that your experiments are an improvement (in your words) over what they just payed hard-earned cash for. Few will have the bin of components that you have assembled and tweaked to get flying. Fewer will have your knowledge of how to make it all work. This is the "Multi-Rotor" forum and such is largely for people with counter-rotating coaxial helicopters.

We either engage in truth-telling here or we are wasting everyone's time.

Best Regards

ok, i did not say retaining "factory config" as obviously it acts as a FP flyer. Even new guys on the field deserve to know the possibilities and this can only be done through experimentation and bascially the presentation of results.
EQMOD is offline Find More Posts by EQMOD
Reply With Quote
Old Apr 01, 2008, 08:03 PM
Registered User
rbinc's Avatar
Californication
Joined Nov 2007
1,234 Posts
Quote:
Originally Posted by EQMOD
No need to those complicated flybar/paddled/or dual flybars. If you want a 90 degree configuration, there are two simple ways to do it;

1. remove the pitch link going to the upper blades and simply use the upper blades as a flybar stabilized lift control blades and the let the two lower blades handle the direction.

2. Mount the pitch link of the upper blades directly to the swashplate and the mount point should be 90 degrees from the mount point of the two pitch links intended for the lower blades.
Sigh...

1.) The factory helicopter has NO "pitch link going to the upper blades". It has a link to the flybar and there is no change in pitch. It is a gyroscope. Further, we were talking about the two rotor systems being FIXED together at 90 degrees. You cannot let "the two lower blades handle direction" when the upper rotors are FIXED to the lowers. They have to work in unison.

2.) The factory helicopter has NO "pitch link going to the upper blades". It has a link to the flybar and there is no change in pitch. It is a gyroscope. Further, we were talking about the two rotor systems being FIXED together at 90 degrees. You cannot let "the two lower blades handle direction" when the upper rotors are FIXED to the lowers. They have to work in unison.

Let's let this go?

Regards
rbinc is offline Find More Posts by rbinc
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
Discussion LAMA V4 with a Functional Tail Rotor EQMOD Micro Helis 15 Mar 21, 2008 07:10 PM
Discussion Tail Rotor - Rotation Direction? KarbonBird Mini Helis 2 Nov 23, 2006 03:34 PM
Tail Rotor Control Play In Hirobo Lama Gannex Fuel Heli Talk 5 Jan 31, 2005 10:00 PM
corona cf rod for tail rotor pitch control derway Electric Heli Talk 1 Nov 08, 2003 05:55 PM