Pull Pull Rudder
11-13-2009 | 11:36 PM
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From: Port MacquarieNew South Wales, AUSTRALIA
RE: Pull Pull Rudder
Hi billd76,
There arn't any real tricks to pull/pull connections just make sure the rudder horn is firmly mounted and the cabels are slack free but NOT tight.
Cheers,
Colin
There arn't any real tricks to pull/pull connections just make sure the rudder horn is firmly mounted and the cabels are slack free but NOT tight.
Cheers,
Colin
11-14-2009 | 09:19 AM
#5
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RE: Pull Pull Rudder
Of key importance in any pull/pull installation is for the two surface horns clevis holes to be lined up perfectly laterally and through the exact hingeline of the surface. If there is any discrepancy in the alignment either fore or aft then differential will be induced and there will be a slack line situation on movement in both directions.
For all practical purposes the chief reason for pull/pull is to save weight aft of the CG for airplanes that may have tail heaviness problems. That sure applied to my Balsa Nova I built some years back. The Morris kits lumber was overly heavy at least in mine and the structure was a bit overdone. Take care in your CG considerations and the airplane is a great flyer however you will enjoy it. I recently gave the old bird away to the gentleman in the photo and he is sure enjoying it.
John
For all practical purposes the chief reason for pull/pull is to save weight aft of the CG for airplanes that may have tail heaviness problems. That sure applied to my Balsa Nova I built some years back. The Morris kits lumber was overly heavy at least in mine and the structure was a bit overdone. Take care in your CG considerations and the airplane is a great flyer however you will enjoy it. I recently gave the old bird away to the gentleman in the photo and he is sure enjoying it.
John
11-14-2009 | 09:38 AM
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From: Nottingham,
PA
RE: Pull Pull Rudder
ORIGINAL: JohnBuckner
Of key importance in any pull/pull installation is for the two surface horns clevis holes to be lined up perfectly laterally and through the exact hingeline of the surface. If there is any discrepancy in the alignment either fore or aft then differential will be induced and there will be a slack line situation on movement in both directions.
For all practical purposes the chief reason for pull/pull is to save weight aft of the CG for airplanes that may have tail heaviness problems. That sure applied to my Balsa Nova I built some years back. The Morris kits lumber was overly heavy at least in mine and the structure was a bit overdone. Take care in your CG considerations and the airplane is a great flyer however you will enjoy it. I recently gave the old bird away to the gentleman in the photo and he is sure enjoying it.
John
Of key importance in any pull/pull installation is for the two surface horns clevis holes to be lined up perfectly laterally and through the exact hingeline of the surface. If there is any discrepancy in the alignment either fore or aft then differential will be induced and there will be a slack line situation on movement in both directions.
For all practical purposes the chief reason for pull/pull is to save weight aft of the CG for airplanes that may have tail heaviness problems. That sure applied to my Balsa Nova I built some years back. The Morris kits lumber was overly heavy at least in mine and the structure was a bit overdone. Take care in your CG considerations and the airplane is a great flyer however you will enjoy it. I recently gave the old bird away to the gentleman in the photo and he is sure enjoying it.
John
11-14-2009 | 10:00 AM
#7
Senior Member
RE: Pull Pull Rudder
As one who uses pull-pull on nearly all my planes, on both rudder and elevator, I have found that you always want some positive Ackerman in any pull-pull. If you do not know what Ackerman is, just google for it as there is a lot of good info available . Basically, it is adjusting the attachment points relative to the hinge point so that the line NOT being pulled on always goes a bit slack as you move the surface away from neutral. The trouble most people get into on their first pull-pull is to get some negative Ackerman built in and that can cause all kinds of problems as it causes excessive current drain on the servos as well as possibly causing binding and/or restriction on amount of throw.
11-14-2009 | 11:10 AM
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From: Nottingham,
PA
RE: Pull Pull Rudder
ORIGINAL: Rodney
As one who uses pull-pull on nearly all my planes, on both rudder and elevator, I have found that you always want some positive Ackerman in any pull-pull. If you do not know what Ackerman is, just google for it as there is a lot of good info available . Basically, it is adjusting the attachment points relative to the hinge point so that the line NOT being pulled on always goes a bit slack as you move the surface away from neutral. The trouble most people get into on their first pull-pull is to get some negative Ackerman built in and that can cause all kinds of problems as it causes excessive current drain on the servos as well as possibly causing binding and/or restriction on amount of throw.
As one who uses pull-pull on nearly all my planes, on both rudder and elevator, I have found that you always want some positive Ackerman in any pull-pull. If you do not know what Ackerman is, just google for it as there is a lot of good info available . Basically, it is adjusting the attachment points relative to the hinge point so that the line NOT being pulled on always goes a bit slack as you move the surface away from neutral. The trouble most people get into on their first pull-pull is to get some negative Ackerman built in and that can cause all kinds of problems as it causes excessive current drain on the servos as well as possibly causing binding and/or restriction on amount of throw.
11-14-2009 | 11:33 AM
#9
RE: Pull Pull Rudder
All I have ever used is the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD858&P=0]Dubro pull-pull.[/link] The cable threads through the rigging couplers, then wound throw the crimp. The rigging couplers are threaded and the clevises screw on to them. A locknut is also used on the clevis/rigging assembly.
11-14-2009 | 02:36 PM
#10
My Feedback: (1)
RE: Pull Pull Rudder
Yes, with that type of crimpinng sleeve you simply crimp after routing as you described. you can also use short peices of brass tubing for crimpers if you don,t want to buy expensive pull/pull sets.
Another method I often use on the airplanes I choose to use pull/pull is to use a clevis threaded onto a solder on thread fitting. Just flatten the end that the wire rod is normally inserted and soldered. Then drill a small hole for spider wire which works great tied directly through this hole and dripped with a drop of Ca. This works well with a lot of lighter aircraft, old timers and such. Have used pull/pull on a fair number of my old timer types even on elevators this of course for the need to minimise weight aft of the CG.
My Balsa Nova was a working airplane that was needed quickly for the use as a pace plane in the old Scale Warbird Racing Association events used at a number of southwestern fields. Typically the airplane would be required fly working normally with three other pace planes for around one minute every fifteen minutes for a total of around fifty flights in a long race day. This required a lot of fore thought to keep the pace planes going with shared pilot duties and refueling and servicing. That why the upright engine for ease of ignitor use and fueling with a visible and accessable fuel tank. In some cases we also used converted Q-500 airplane with taxi capable tri gears for pace planes also. The Balsa Nova is a very easy airplane to land and more importantly easy to taxi and get off the runway quickly. Important for that type of application.
John
Another method I often use on the airplanes I choose to use pull/pull is to use a clevis threaded onto a solder on thread fitting. Just flatten the end that the wire rod is normally inserted and soldered. Then drill a small hole for spider wire which works great tied directly through this hole and dripped with a drop of Ca. This works well with a lot of lighter aircraft, old timers and such. Have used pull/pull on a fair number of my old timer types even on elevators this of course for the need to minimise weight aft of the CG.
My Balsa Nova was a working airplane that was needed quickly for the use as a pace plane in the old Scale Warbird Racing Association events used at a number of southwestern fields. Typically the airplane would be required fly working normally with three other pace planes for around one minute every fifteen minutes for a total of around fifty flights in a long race day. This required a lot of fore thought to keep the pace planes going with shared pilot duties and refueling and servicing. That why the upright engine for ease of ignitor use and fueling with a visible and accessable fuel tank. In some cases we also used converted Q-500 airplane with taxi capable tri gears for pace planes also. The Balsa Nova is a very easy airplane to land and more importantly easy to taxi and get off the runway quickly. Important for that type of application.
John
11-14-2009 | 03:06 PM
#11
My Feedback: (-1)
RE: Pull Pull Rudder
Life was just so much easier before we heard of Ackerman, who is this person?? How did we ever get our pull/pull systems to work before he invented Ackerman?? Just boggles my mind.
Yes, all my rudders had slack on one side when I turned but they worked, I never really cared about the slack, it was a pull/pull system, not a push pull so who cared, just the nature of the beast. Now days I have perfect rudder pull/pull systems because someone wrote about this Ackerman guy and a lot of nim rods read about it. When they look at one of my planes and there is slack on one side of the rudder cable I must hang my head in shame. Truth is someone in a magazine showed us how to set up a pull/pull correctly and I have been doing it ever sense. I make up my own systems and save a few bucks. I go to Bass Pro and buy rolls of braided stainless steel leader with the plastic coating, I can get it in several diffrent weights so I have thick and thin on hand for different sizes of planes. I buy rigging couplers in 2-56 and 4-40 and I can make up my own rudder tillers or buy some of the nice Dubros. I haven't bought any of the complete systems in years. Now if we could only find out who this Ackerman guy is and hang him!!
Yes, all my rudders had slack on one side when I turned but they worked, I never really cared about the slack, it was a pull/pull system, not a push pull so who cared, just the nature of the beast. Now days I have perfect rudder pull/pull systems because someone wrote about this Ackerman guy and a lot of nim rods read about it. When they look at one of my planes and there is slack on one side of the rudder cable I must hang my head in shame. Truth is someone in a magazine showed us how to set up a pull/pull correctly and I have been doing it ever sense. I make up my own systems and save a few bucks. I go to Bass Pro and buy rolls of braided stainless steel leader with the plastic coating, I can get it in several diffrent weights so I have thick and thin on hand for different sizes of planes. I buy rigging couplers in 2-56 and 4-40 and I can make up my own rudder tillers or buy some of the nice Dubros. I haven't bought any of the complete systems in years. Now if we could only find out who this Ackerman guy is and hang him!!
11-14-2009 | 06:18 PM
#12
My Feedback: (1)
RE: Pull Pull Rudder
ORIGINAL: Gray Beard
Life was just so much easier before we heard of Ackerman, who is this person?? How did we ever get our pull/pull systems to work before he invented Ackerman??
Life was just so much easier before we heard of Ackerman, who is this person?? How did we ever get our pull/pull systems to work before he invented Ackerman??
[sm=biggrin.gif][sm=idea.gif] He,he trial and error thats how? But of course you already knew that.
John
11-14-2009 | 09:21 PM
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From: Grovetown, GA
RE: Pull Pull Rudder
I had a blast with my Balsa Nova. Mine was flown with a 45 2stroke and a tuned pipe and it was fast but with that thick wing it landed like a trainer. Good luck with yours.
When crimping the sleeve be careful and crimp towards the center of the sleeve and not pinch the ends as they may actually cut the cable.
Tom
When crimping the sleeve be careful and crimp towards the center of the sleeve and not pinch the ends as they may actually cut the cable.
Tom
11-14-2009 | 09:26 PM
#14
My Feedback: (1)
RE: Pull Pull Rudder
To make life simpler, Bill, the bottom line is to center the servo, make the attachements with the straightest connection between the servo and the control horns, and then don't try to remove 100% of the slack. It just won't happen.
I use a vinyl coated cevlar cord (see link below). Great stuff, comes in two sizes. I threw away the steel cable stuff, in favor of this cevlar cord. It's strong, but very easy to manipulate and to tie knots with (hey, Coast Guard Retired, remember? ha.. oops) And, if and when it may become frayed, and it can and will happen, it's easy to replace.
http://www.thunderboltrc.com/index.p...roducts_id=580
They make different thicknesses. This one is .038" but there is.058 I believe and other thicknesses.
Of course, there are the physics of the connections. Use the same conrol horns on both sides, do your best to make sure the control horns are mounted in as close to exactly the same position on the left as on the right (and, of course, vice versa..
) and then make sure you absolutely center the servo with your transmitter set to exact center with the trim at as close to center as possible.. then make the connections WITH THE SERVO'S ENERGIZED. Use the strength of the servo to insure maintaining centering.
Once done, you will have a well centered and balanced pull-pull rudder installation.
Oh my gosh.. next project.. having a pull-pull elevator AND an pull-pull rudder ( as in the Excelleron 90 installation.. quite a challenge!!)
CGr.
I use a vinyl coated cevlar cord (see link below). Great stuff, comes in two sizes. I threw away the steel cable stuff, in favor of this cevlar cord. It's strong, but very easy to manipulate and to tie knots with (hey, Coast Guard Retired, remember? ha.. oops) And, if and when it may become frayed, and it can and will happen, it's easy to replace.
http://www.thunderboltrc.com/index.p...roducts_id=580
They make different thicknesses. This one is .038" but there is.058 I believe and other thicknesses.
Of course, there are the physics of the connections. Use the same conrol horns on both sides, do your best to make sure the control horns are mounted in as close to exactly the same position on the left as on the right (and, of course, vice versa..
) and then make sure you absolutely center the servo with your transmitter set to exact center with the trim at as close to center as possible.. then make the connections WITH THE SERVO'S ENERGIZED. Use the strength of the servo to insure maintaining centering.Once done, you will have a well centered and balanced pull-pull rudder installation.
Oh my gosh.. next project.. having a pull-pull elevator AND an pull-pull rudder ( as in the Excelleron 90 installation.. quite a challenge!!)
CGr.
11-15-2009 | 05:39 PM
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From: Nottingham,
PA
RE: Pull Pull Rudder
ORIGINAL: CGRetired
To make life simpler, Bill, the bottom line is to center the servo, make the attachements with the straightest connection between the servo and the control horns, and then don't try to remove 100% of the slack. It just won't happen.
I use a vinyl coated cevlar cord (see link below). Great stuff, comes in two sizes. I threw away the steel cable stuff, in favor of this cevlar cord. It's strong, but very easy to manipulate and to tie knots with (hey, Coast Guard Retired, remember? ha.. oops) And, if and when it may become frayed, and it can and will happen, it's easy to replace.
http://www.thunderboltrc.com/index.p...roducts_id=580
They make different thicknesses. This one is .038'' but there is.058 I believe and other thicknesses.
Of course, there are the physics of the connections. Use the same conrol horns on both sides, do your best to make sure the control horns are mounted in as close to exactly the same position on the left as on the right (and, of course, vice versa.. ) and then make sure you absolutely center the servo with your transmitter set to exact center with the trim at as close to center as possible.. then make the connections WITH THE SERVO'S ENERGIZED. Use the strength of the servo to insure maintaining centering.
Once done, you will have a well centered and balanced pull-pull rudder installation.
Oh my gosh.. next project.. having a pull-pull elevator AND an pull-pull rudder ( as in the Excelleron 90 installation.. quite a challenge!!)
CGr.
To make life simpler, Bill, the bottom line is to center the servo, make the attachements with the straightest connection between the servo and the control horns, and then don't try to remove 100% of the slack. It just won't happen.
I use a vinyl coated cevlar cord (see link below). Great stuff, comes in two sizes. I threw away the steel cable stuff, in favor of this cevlar cord. It's strong, but very easy to manipulate and to tie knots with (hey, Coast Guard Retired, remember? ha.. oops) And, if and when it may become frayed, and it can and will happen, it's easy to replace.
http://www.thunderboltrc.com/index.p...roducts_id=580
They make different thicknesses. This one is .038'' but there is.058 I believe and other thicknesses.
Of course, there are the physics of the connections. Use the same conrol horns on both sides, do your best to make sure the control horns are mounted in as close to exactly the same position on the left as on the right (and, of course, vice versa..
) and then make sure you absolutely center the servo with your transmitter set to exact center with the trim at as close to center as possible.. then make the connections WITH THE SERVO'S ENERGIZED. Use the strength of the servo to insure maintaining centering.Once done, you will have a well centered and balanced pull-pull rudder installation.
Oh my gosh.. next project.. having a pull-pull elevator AND an pull-pull rudder ( as in the Excelleron 90 installation.. quite a challenge!!)
CGr.
11-15-2009 | 08:47 PM
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From: Nottingham,
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RE: Pull Pull Rudder
ORIGINAL: JohnBuckner
Yes, with that type of crimpinng sleeve you simply crimp after routing as you described. you can also use short peices of brass tubing for crimpers if you don,t want to buy expensive pull/pull sets.
Another method I often use on the airplanes I choose to use pull/pull is to use a clevis threaded onto a solder on thread fitting. Just flatten the end that the wire rod is normally inserted and soldered. Then drill a small hole for spider wire which works great tied directly through this hole and dripped with a drop of Ca. This works well with a lot of lighter aircraft, old timers and such. Have used pull/pull on a fair number of my old timer types even on elevators this of course for the need to minimise weight aft of the CG.
My Balsa Nova was a working airplane that was needed quickly for the use as a pace plane in the old Scale Warbird Racing Association events used at a number of southwestern fields. Typically the airplane would be required fly working normally with three other pace planes for around one minute every fifteen minutes for a total of around fifty flights in a long race day. This required a lot of fore thought to keep the pace planes going with shared pilot duties and refueling and servicing. That why the upright engine for ease of ignitor use and fueling with a visible and accessable fuel tank. In some cases we also used converted Q-500 airplane with taxi capable tri gears for pace planes also. The Balsa Nova is a very easy airplane to land and more importantly easy to taxi and get off the runway quickly. Important for that type of application.
John
Yes, with that type of crimpinng sleeve you simply crimp after routing as you described. you can also use short peices of brass tubing for crimpers if you don,t want to buy expensive pull/pull sets.
Another method I often use on the airplanes I choose to use pull/pull is to use a clevis threaded onto a solder on thread fitting. Just flatten the end that the wire rod is normally inserted and soldered. Then drill a small hole for spider wire which works great tied directly through this hole and dripped with a drop of Ca. This works well with a lot of lighter aircraft, old timers and such. Have used pull/pull on a fair number of my old timer types even on elevators this of course for the need to minimise weight aft of the CG.
My Balsa Nova was a working airplane that was needed quickly for the use as a pace plane in the old Scale Warbird Racing Association events used at a number of southwestern fields. Typically the airplane would be required fly working normally with three other pace planes for around one minute every fifteen minutes for a total of around fifty flights in a long race day. This required a lot of fore thought to keep the pace planes going with shared pilot duties and refueling and servicing. That why the upright engine for ease of ignitor use and fueling with a visible and accessable fuel tank. In some cases we also used converted Q-500 airplane with taxi capable tri gears for pace planes also. The Balsa Nova is a very easy airplane to land and more importantly easy to taxi and get off the runway quickly. Important for that type of application.
John
. It sure would've been alot easier to cut the cowl that way!! Wow!!Speaking of which, did any of you Nova owners apply 2 degrees right thrust? There doesn't appear to be any thrust angles built into the firewall. And also what size props are you spinning? Thanks
