wing rocking how to stop it
01-19-2004 | 07:33 PM
#1
Thread Starter
Senior Member
My Feedback: (2)
Joined: Nov 2002
Posts: 125
Likes: 0
Received 0 Likes
on
0 Posts
From: gj, CO
wing rocking how to stop it
How can I stop the wing rock win I try to do harrier on my dave patrick extra 330. the cg is between the specefed point but have not latorally balanced it yet. It does not rock win I do it with low rates but the angle is not what I hoped it would be with low rates. one more thing Iam at 5000 ft in colorado and my moki 1.8 wiil not pull out of a hover do you think or now any one runing a DA 50 on a 15lbs plane up this high and if so would that motor give me the power I need.
01-21-2004 | 12:00 AM
#3
RE: wing rocking how to stop it
That motor will definitely give you the performance you desire. As for the wing rocking is sounds nose heavy to me and like it does not have enough elev. on high rate to maintain a full stall. Wing rocking is primarily caused by the plane stalling, then picking up a little speed and trying to fly, then imediately stalling again. It does this over and over and everytime it stalls it causes the rocking to increase. Make sure you can get 40-45 degrees of elev. and then start adding some tailweight if that isn't enough.
Also do not hesitate to add a few click of throttle, the additional prop blast over the stab helps a lot.
Chip
Also do not hesitate to add a few click of throttle, the additional prop blast over the stab helps a lot.
Chip
ORIGINAL: lcgj
Don't forget to help me out I need it. thanks
Don't forget to help me out I need it. thanks
01-21-2004 | 09:04 PM
#5
Thread Starter
Senior Member
My Feedback: (2)
Joined: Nov 2002
Posts: 125
Likes: 0
Received 0 Likes
on
0 Posts
From: gj, CO
RE: wing rocking how to stop it
Yes I now I have asked this before sorry. But there is no one else to learn from. I will try to fly the dam thing right. I am the only one were I fly that tries to do 3 D. I "ve almost got hover. It sucks being the only one.
THANKS
THANKS
01-21-2004 | 09:57 PM
#6
My Feedback: (11)
Joined: Jul 2003
Posts: 2,080
Likes: 0
Received 0 Likes
on
0 Posts
From: Tracy,
CA
RE: wing rocking how to stop it
I have a moki 2.10 in mine and lemme tell ya, POWER!!!!!!!!!!! Pulls like you wouldn't believe. I can't get the wings to stop rocking either. Just fight it with ailerons. S'all you can do with it. Good luck. Chris
01-22-2004 | 10:26 AM
#7
Senior Member
Joined: Sep 2003
Posts: 205
Likes: 0
Received 0 Likes
on
0 Posts
From: Granbury,
TX
RE: wing rocking how to stop it
The wing rock happens as a wing gets enough lift to start flying again. Once it produces lift, it also produces drag and the resulting yaw, it moves itself out of the airflow and drives the opposite wing into the airflow. The first wing then looses lift and the opposite one now has enough airflow that it begins to fly, and the process amplifies.
The problem is compounded by the fact part of your rudder is blanketed by the elevator during a harrier, and the rudder is what you need to stop the rocking. Swept wings increase the effect - jets call it "dutch roll" and have yaw dampers to prevent it......not aileron dampers, but yaw (rudder) dampers!
The lower your forward speed, the less tendancy the plane will have to enter the oscillation. On calm days you will probably have little trouble with wingrock. Windy days will help inititate the rocking. On a windy day your plane is moving faster through the air - even though it may not be moving at all over the ground. That forward speed will make it easier for the wing to get lift to begin the rocking. Gusts will also start the rocking. Once it starts it only gets worse until you do something to stop it.
That's the theory - now to work with it........
Stop it by adding rudder to counter the rocking. You have to lead your application, though. The rudder has some lag involved wiith it, so you have to apply it before it is actually needed. For example: If you wait until the left wing is up to add left rudder, the plane will start to reverse on its own about the same time the rudder takes effect.......so the right wing comes up with a vengence. You have to add the left rudder when the left wing just starts to rise, and release it as it passes level.
Aileron will not help as the wing doesn't have an efficient airflow over it. Adding aileron will increase drag on the low wing and make the yaw worse, so the rocking gets worse. Remember, it is a YAW problem, not a roll problem. The rolling is a result of the yaw.
By the way, most planes don't start the rocking in an inverted harrier. Can you guess why? Just remember that your rudder is reversed in the inverted harrier. (ie. use left rudder to raise the wing on the right and vice versa).
Bottom line.........lots of practice using rudder! Have fun.........
CJ
The problem is compounded by the fact part of your rudder is blanketed by the elevator during a harrier, and the rudder is what you need to stop the rocking. Swept wings increase the effect - jets call it "dutch roll" and have yaw dampers to prevent it......not aileron dampers, but yaw (rudder) dampers!
The lower your forward speed, the less tendancy the plane will have to enter the oscillation. On calm days you will probably have little trouble with wingrock. Windy days will help inititate the rocking. On a windy day your plane is moving faster through the air - even though it may not be moving at all over the ground. That forward speed will make it easier for the wing to get lift to begin the rocking. Gusts will also start the rocking. Once it starts it only gets worse until you do something to stop it.
That's the theory - now to work with it........
Stop it by adding rudder to counter the rocking. You have to lead your application, though. The rudder has some lag involved wiith it, so you have to apply it before it is actually needed. For example: If you wait until the left wing is up to add left rudder, the plane will start to reverse on its own about the same time the rudder takes effect.......so the right wing comes up with a vengence. You have to add the left rudder when the left wing just starts to rise, and release it as it passes level.
Aileron will not help as the wing doesn't have an efficient airflow over it. Adding aileron will increase drag on the low wing and make the yaw worse, so the rocking gets worse. Remember, it is a YAW problem, not a roll problem. The rolling is a result of the yaw.
By the way, most planes don't start the rocking in an inverted harrier. Can you guess why? Just remember that your rudder is reversed in the inverted harrier. (ie. use left rudder to raise the wing on the right and vice versa).
Bottom line.........lots of practice using rudder! Have fun.........
CJ
01-22-2004 | 11:58 PM
#10
My Feedback: (38)
RE: wing rocking how to stop it
Well, I have to disagree, the ailerons work just fine in a harrier and that is what to use to counter wing rocking, rudder is more used for directional control, if the rudder took care of the wing rocking, how would you be able to turn a corner......
01-23-2004 | 01:31 AM
#11
RE: wing rocking how to stop it
ORIGINAL: Blow n Go
The wing rock happens as a wing gets enough lift to start flying again. Once it produces lift, it also produces drag and the resulting yaw, it moves itself out of the airflow and drives the opposite wing into the airflow. The first wing then looses lift and the opposite one now has enough airflow that it begins to fly, and the process amplifies.
The problem is compounded by the fact part of your rudder is blanketed by the elevator during a harrier, and the rudder is what you need to stop the rocking. Swept wings increase the effect - jets call it "dutch roll" and have yaw dampers to prevent it......not aileron dampers, but yaw (rudder) dampers!
The lower your forward speed, the less tendancy the plane will have to enter the oscillation. On calm days you will probably have little trouble with wingrock. Windy days will help inititate the rocking. On a windy day your plane is moving faster through the air - even though it may not be moving at all over the ground. That forward speed will make it easier for the wing to get lift to begin the rocking. Gusts will also start the rocking. Once it starts it only gets worse until you do something to stop it.
That's the theory - now to work with it........
Stop it by adding rudder to counter the rocking. You have to lead your application, though. The rudder has some lag involved wiith it, so you have to apply it before it is actually needed. For example: If you wait until the left wing is up to add left rudder, the plane will start to reverse on its own about the same time the rudder takes effect.......so the right wing comes up with a vengence. You have to add the left rudder when the left wing just starts to rise, and release it as it passes level.
Aileron will not help as the wing doesn't have an efficient airflow over it. Adding aileron will increase drag on the low wing and make the yaw worse, so the rocking gets worse. Remember, it is a YAW problem, not a roll problem. The rolling is a result of the yaw.
By the way, most planes don't start the rocking in an inverted harrier. Can you guess why? Just remember that your rudder is reversed in the inverted harrier. (ie. use left rudder to raise the wing on the right and vice versa).
Bottom line.........lots of practice using rudder! Have fun.........
CJ
The wing rock happens as a wing gets enough lift to start flying again. Once it produces lift, it also produces drag and the resulting yaw, it moves itself out of the airflow and drives the opposite wing into the airflow. The first wing then looses lift and the opposite one now has enough airflow that it begins to fly, and the process amplifies.
The problem is compounded by the fact part of your rudder is blanketed by the elevator during a harrier, and the rudder is what you need to stop the rocking. Swept wings increase the effect - jets call it "dutch roll" and have yaw dampers to prevent it......not aileron dampers, but yaw (rudder) dampers!
The lower your forward speed, the less tendancy the plane will have to enter the oscillation. On calm days you will probably have little trouble with wingrock. Windy days will help inititate the rocking. On a windy day your plane is moving faster through the air - even though it may not be moving at all over the ground. That forward speed will make it easier for the wing to get lift to begin the rocking. Gusts will also start the rocking. Once it starts it only gets worse until you do something to stop it.
That's the theory - now to work with it........
Stop it by adding rudder to counter the rocking. You have to lead your application, though. The rudder has some lag involved wiith it, so you have to apply it before it is actually needed. For example: If you wait until the left wing is up to add left rudder, the plane will start to reverse on its own about the same time the rudder takes effect.......so the right wing comes up with a vengence. You have to add the left rudder when the left wing just starts to rise, and release it as it passes level.
Aileron will not help as the wing doesn't have an efficient airflow over it. Adding aileron will increase drag on the low wing and make the yaw worse, so the rocking gets worse. Remember, it is a YAW problem, not a roll problem. The rolling is a result of the yaw.
By the way, most planes don't start the rocking in an inverted harrier. Can you guess why? Just remember that your rudder is reversed in the inverted harrier. (ie. use left rudder to raise the wing on the right and vice versa).
Bottom line.........lots of practice using rudder! Have fun.........
CJ
It occurs because the plane is constantly trying to stall due to being nose heavy or not enough elevator throw, or both. Most planes do it worse upright because the majority of there weight is above the centerline of the wing. Inverted it is below the centerline.
Chip
01-23-2004 | 02:02 AM
#12
Senior Member
My Feedback: (5)
Joined: Jul 2003
Posts: 2,668
Likes: 0
Received 0 Likes
on
0 Posts
From: Tacoma, WA
RE: wing rocking how to stop it
A while back I had my elevators set to 30° of throw. Harriers were alright but not great. THing is, they had 0 wingrock. I Double-beveled my elevators to get 50° of throw and now they rock somethign horrid. What happened?
01-23-2004 | 02:15 AM
#13
RE: wing rocking how to stop it
ORIGINAL: 3DFanatic
A while back I had my elevators set to 30° of throw. Harriers were alright but not great. THing is, they had 0 wingrock. I Double-beveled my elevators to get 50° of throw and now they rock somethign horrid. What happened?
A while back I had my elevators set to 30° of throw. Harriers were alright but not great. THing is, they had 0 wingrock. I Double-beveled my elevators to get 50° of throw and now they rock somethign horrid. What happened?
Chip
01-23-2004 | 02:29 AM
#14
Senior Member
My Feedback: (5)
Joined: Jul 2003
Posts: 2,668
Likes: 0
Received 0 Likes
on
0 Posts
From: Tacoma, WA
RE: wing rocking how to stop it
Haven't you heard the phrase if it ain't broke take it apart and find out why? 
I changed it beacause of my decent angle, I wanted it to be a bit steeper.
I changed it beacause of my decent angle, I wanted it to be a bit steeper.
01-23-2004 | 10:21 PM
#15
Senior Member
Joined: Sep 2003
Posts: 205
Likes: 0
Received 0 Likes
on
0 Posts
From: Granbury,
TX
RE: wing rocking how to stop it
OK guys................let's get this straight.............
If your ailerons work in a fully stalled harrier, it is because you have prop wash over the inner surfaces. Period. Not all airframes get wash over the ailerons, so you can't blanketly say the ailerons work fine in a harrier. On some planes they will and on some they won't.........but that's not causing the rocking.
Bipes are also more stable in an inverted harrier, and the CG is way above the wing centers in that condition (or aerodynamic center to be correct) . If CG location was the cause, then the plane would not rock, but just flip over and stick with the CG down. That's not causing the rocking either.
This whole wingrock deal is yaw instablility. What everone is describing are the characteristics of particular airframes and at what point they become unstable in yaw. Every design is different, and it is not simple to predict the airflow over the rear of a fuselage....... stability is affected by the wash from the wings, the prop, and the elevator location and deflection to name a few variables. Even the big boys have messed it up on full scale airplanes on occasion. They solve it by adding bigger vertical stabilizers - not more elevator throw, or bigger ailerons.
You are all correct in describing what your planes are doing. Just remember that if the rocking is a problem on your plane, then rudder is what is going to fix the problem.
Here's another grain for thought.......I bet most of you guys that get wing rock have more effective rudders than those that don't...........How come?
CJ
If your ailerons work in a fully stalled harrier, it is because you have prop wash over the inner surfaces. Period. Not all airframes get wash over the ailerons, so you can't blanketly say the ailerons work fine in a harrier. On some planes they will and on some they won't.........but that's not causing the rocking.
Bipes are also more stable in an inverted harrier, and the CG is way above the wing centers in that condition (or aerodynamic center to be correct) . If CG location was the cause, then the plane would not rock, but just flip over and stick with the CG down. That's not causing the rocking either.
This whole wingrock deal is yaw instablility. What everone is describing are the characteristics of particular airframes and at what point they become unstable in yaw. Every design is different, and it is not simple to predict the airflow over the rear of a fuselage....... stability is affected by the wash from the wings, the prop, and the elevator location and deflection to name a few variables. Even the big boys have messed it up on full scale airplanes on occasion. They solve it by adding bigger vertical stabilizers - not more elevator throw, or bigger ailerons.
You are all correct in describing what your planes are doing. Just remember that if the rocking is a problem on your plane, then rudder is what is going to fix the problem.
Here's another grain for thought.......I bet most of you guys that get wing rock have more effective rudders than those that don't...........How come?
CJ
01-23-2004 | 10:39 PM
#16
RE: wing rocking how to stop it
Not sure where you get this stuff from, but have you ever tried to do an inverted Harrier with a bipe, its almost IMPOSSIBLE. I don't want to argue your Rudder theory, it sounds like you read it in a book, but I do know from experience the fin area has little or nothing to do with wing rocking.
Chip
Chip
ORIGINAL: Blow n Go
OK guys................let's get this straight.............
If your ailerons work in a fully stalled harrier, it is because you have prop wash over the inner surfaces. Period. Not all airframes get wash over the ailerons, so you can't blanketly say the ailerons work fine in a harrier. On some planes they will and on some they won't.........but that's not causing the rocking.
Bipes are also more stable in an inverted harrier, and the CG is way above the wing centers in that condition (or aerodynamic center to be correct) . If CG location was the cause, then the plane would not rock, but just flip over and stick with the CG down. That's not causing the rocking either.
This whole wingrock deal is yaw instablility. What everone is describing are the characteristics of particular airframes and at what point they become unstable in yaw. Every design is different, and it is not simple to predict the airflow over the rear of a fuselage....... stability is affected by the wash from the wings, the prop, and the elevator location and deflection to name a few variables. Even the big boys have messed it up on full scale airplanes on occasion. They solve it by adding bigger vertical stabilizers - not more elevator throw, or bigger ailerons.
You are all correct in describing what your planes are doing. Just remember that if the rocking is a problem on your plane, then rudder is what is going to fix the problem.
Here's another grain for thought.......I bet most of you guys that get wing rock have more effective rudders than those that don't...........How come?
CJ
OK guys................let's get this straight.............
If your ailerons work in a fully stalled harrier, it is because you have prop wash over the inner surfaces. Period. Not all airframes get wash over the ailerons, so you can't blanketly say the ailerons work fine in a harrier. On some planes they will and on some they won't.........but that's not causing the rocking.
Bipes are also more stable in an inverted harrier, and the CG is way above the wing centers in that condition (or aerodynamic center to be correct) . If CG location was the cause, then the plane would not rock, but just flip over and stick with the CG down. That's not causing the rocking either.
This whole wingrock deal is yaw instablility. What everone is describing are the characteristics of particular airframes and at what point they become unstable in yaw. Every design is different, and it is not simple to predict the airflow over the rear of a fuselage....... stability is affected by the wash from the wings, the prop, and the elevator location and deflection to name a few variables. Even the big boys have messed it up on full scale airplanes on occasion. They solve it by adding bigger vertical stabilizers - not more elevator throw, or bigger ailerons.
You are all correct in describing what your planes are doing. Just remember that if the rocking is a problem on your plane, then rudder is what is going to fix the problem.
Here's another grain for thought.......I bet most of you guys that get wing rock have more effective rudders than those that don't...........How come?
CJ
01-23-2004 | 11:51 PM
#17
My Feedback: (38)
RE: wing rocking how to stop it
Thank you Chip.
Use the ailerons to help stop the rocking, watch the pro's, they use them, propwash or not, it works, Ive done it.. Go ahead and try the rudder only, make sure to get us a vid of that one, if you try it low, bring a bag for clean up as its not going to do it. It will keep rocking, and rock more on each oscillation.
Thanks
my .25
Use the ailerons to help stop the rocking, watch the pro's, they use them, propwash or not, it works, Ive done it.. Go ahead and try the rudder only, make sure to get us a vid of that one, if you try it low, bring a bag for clean up as its not going to do it. It will keep rocking, and rock more on each oscillation.
Thanks
my .25
01-24-2004 | 09:59 AM
#18
Senior Member
Joined: Aug 2003
Posts: 432
Likes: 0
Received 0 Likes
on
0 Posts
From: Cookeville,
TN
RE: wing rocking how to stop it
It seems to me that the planes i have you have to hold a little right aileron and a little left rudder to stop the wing rock(this is for straight flight).
You still have to turn with the rudder but when you get straight like you want i have to hold a little opposite rudder. I have tried doing it with rudder only and have had no luck.(this may be because my skills arent at expert level)I do know for a fact that the ailerons will stop the wing rock for me(at least on my planes).
It sounds like Blow n Go is applying somekind of aerodynamics classroom theory and actually hasnt tried his theory with a transmitter in his hand(i may be totally wrong).
You still have to turn with the rudder but when you get straight like you want i have to hold a little opposite rudder. I have tried doing it with rudder only and have had no luck.(this may be because my skills arent at expert level)I do know for a fact that the ailerons will stop the wing rock for me(at least on my planes).
It sounds like Blow n Go is applying somekind of aerodynamics classroom theory and actually hasnt tried his theory with a transmitter in his hand(i may be totally wrong).
01-25-2004 | 11:51 AM
#19
Senior Member
Joined: Sep 2003
Posts: 205
Likes: 0
Received 0 Likes
on
0 Posts
From: Granbury,
TX
RE: wing rocking how to stop it
I get this stuff because I have a degree in it - and taught it in the Air Force for 11 years. (Blow 'n Go - if you get in trouble, hit the afterburner and go around - as I would tell my students!) I flew RC long before the AF. I'll be happy to explain what I am writing..........but there is no need to make up accusations about what I can or can't do that have nothing to do with the topic at hand. I assumed you guys were interested in learning something, but it's no sweat if you want to keep your flat earth theories.
Chip, I have 250 flights on your AW ultimate. It is very docile in an inverted harrier, but wing rocks like a SOB on a windy day when upright. I have had the CG forward with a 3W200 and so far aft with a DA150 that the plane climbs when you roll inverted - but its behavior in harrier is unchanged. It stops rocking with rudder, but starts quickly after........because it is unstable in yaw at this angle of attack. Inverted it does not rock, but you must use rudder to control the roll.
Vertical fin area needs to be added to the bottom of the fusealge to stabilize an upright harrier (a la F-16). Fin area on the top of the plane is blanketed by the elevator and fuselage when the free stream airflow approaches 90 degrees and is ineffective.
3DFanatic's example is a perfect demonstration of changing yaw stablility and the result. At 30 degrees of elevator throw the airflow was not that bad over the rudder and the plane was steady. At 50 degrees, you are blocking a considerable portion of the vertical stab with a big board (the elevator), disrupting the airflow, so the configuration becomes unstable in yaw. The result - wing rock.
By the way, I mix aileron into my elevator to get the best of both worlds. Aileron in the elevator does not create gobs of adverse yaw like the ailerons do. My aileron control does work in a harrier, but not like the rudder! I use both aileron and rudder to stop the rocking too, but rudder is the primary. The harrier is an unstable position for our models to fly in.........It takes a little work to keep them there.
.........you can land a plane with no elevator (using power to control pitch), and turn it with no aileron control (using rudder to roll), and you can learn to do both very well.......but that doesn't mean you are using the best control for the job. And for you groupies, I have done both with my fanny in the seat, not reading a book or watching a video.
CJ
Chip, I have 250 flights on your AW ultimate. It is very docile in an inverted harrier, but wing rocks like a SOB on a windy day when upright. I have had the CG forward with a 3W200 and so far aft with a DA150 that the plane climbs when you roll inverted - but its behavior in harrier is unchanged. It stops rocking with rudder, but starts quickly after........because it is unstable in yaw at this angle of attack. Inverted it does not rock, but you must use rudder to control the roll.
Vertical fin area needs to be added to the bottom of the fusealge to stabilize an upright harrier (a la F-16). Fin area on the top of the plane is blanketed by the elevator and fuselage when the free stream airflow approaches 90 degrees and is ineffective.
3DFanatic's example is a perfect demonstration of changing yaw stablility and the result. At 30 degrees of elevator throw the airflow was not that bad over the rudder and the plane was steady. At 50 degrees, you are blocking a considerable portion of the vertical stab with a big board (the elevator), disrupting the airflow, so the configuration becomes unstable in yaw. The result - wing rock.
By the way, I mix aileron into my elevator to get the best of both worlds. Aileron in the elevator does not create gobs of adverse yaw like the ailerons do. My aileron control does work in a harrier, but not like the rudder! I use both aileron and rudder to stop the rocking too, but rudder is the primary. The harrier is an unstable position for our models to fly in.........It takes a little work to keep them there.
.........you can land a plane with no elevator (using power to control pitch), and turn it with no aileron control (using rudder to roll), and you can learn to do both very well.......but that doesn't mean you are using the best control for the job. And for you groupies, I have done both with my fanny in the seat, not reading a book or watching a video.
CJ
01-25-2004 | 06:36 PM
#20
Senior Member
Joined: Aug 2003
Posts: 432
Likes: 0
Received 0 Likes
on
0 Posts
From: Cookeville,
TN
RE: wing rocking how to stop it
Blow n Go,
Looks like i was totally wrong, not the first time , maybe the last...but i doubt it. Meant no disrespect to you just have never heard anything like you said before. I do want to learn, that one reason i visit this forum.
I have one plane that does just as you and 3DFanatic describes (rocks bad with 50 degrees elevator throw not bad with 30degrees)with what you are saying would a bigger rudder help?
Looks like i was totally wrong, not the first time , maybe the last...but i doubt it. Meant no disrespect to you just have never heard anything like you said before. I do want to learn, that one reason i visit this forum.
3DFanatic's example is a perfect demonstration of changing yaw stablility and the result. At 30 degrees of elevator throw the airflow was not that bad over the rudder and the plane was steady. At 50 degrees, you are blocking a considerable portion of the vertical stab with a big board (the elevator), disrupting the airflow, so the configuration becomes unstable in yaw. The result - wing rock.
01-26-2004 | 07:59 AM
#22
RE: wing rocking how to stop it
The ultimate is one of the most stable planes I have flown in a harrier, and I do not recall any wing rock in the wind. I do not have a degree but I know how to make a model fly from experience and the ultimate is in no way unstable in yaw in any attitude that I have had it in.
Chip
Chip
ORIGINAL: Blow n Go
I get this stuff because I have a degree in it - and taught it in the Air Force for 11 years. (Blow 'n Go - if you get in trouble, hit the afterburner and go around - as I would tell my students!) I flew RC long before the AF. I'll be happy to explain what I am writing..........but there is no need to make up accusations about what I can or can't do that have nothing to do with the topic at hand. I assumed you guys were interested in learning something, but it's no sweat if you want to keep your flat earth theories.
Chip, I have 250 flights on your AW ultimate. It is very docile in an inverted harrier, but wing rocks like a SOB on a windy day when upright. I have had the CG forward with a 3W200 and so far aft with a DA150 that the plane climbs when you roll inverted - but its behavior in harrier is unchanged. It stops rocking with rudder, but starts quickly after........because it is unstable in yaw at this angle of attack. Inverted it does not rock, but you must use rudder to control the roll.
Vertical fin area needs to be added to the bottom of the fusealge to stabilize an upright harrier (a la F-16). Fin area on the top of the plane is blanketed by the elevator and fuselage when the free stream airflow approaches 90 degrees and is ineffective.
3DFanatic's example is a perfect demonstration of changing yaw stablility and the result. At 30 degrees of elevator throw the airflow was not that bad over the rudder and the plane was steady. At 50 degrees, you are blocking a considerable portion of the vertical stab with a big board (the elevator), disrupting the airflow, so the configuration becomes unstable in yaw. The result - wing rock.
By the way, I mix aileron into my elevator to get the best of both worlds. Aileron in the elevator does not create gobs of adverse yaw like the ailerons do. My aileron control does work in a harrier, but not like the rudder! I use both aileron and rudder to stop the rocking too, but rudder is the primary. The harrier is an unstable position for our models to fly in.........It takes a little work to keep them there.
.........you can land a plane with no elevator (using power to control pitch), and turn it with no aileron control (using rudder to roll), and you can learn to do both very well.......but that doesn't mean you are using the best control for the job. And for you groupies, I have done both with my fanny in the seat, not reading a book or watching a video.
CJ
I get this stuff because I have a degree in it - and taught it in the Air Force for 11 years. (Blow 'n Go - if you get in trouble, hit the afterburner and go around - as I would tell my students!) I flew RC long before the AF. I'll be happy to explain what I am writing..........but there is no need to make up accusations about what I can or can't do that have nothing to do with the topic at hand. I assumed you guys were interested in learning something, but it's no sweat if you want to keep your flat earth theories.
Chip, I have 250 flights on your AW ultimate. It is very docile in an inverted harrier, but wing rocks like a SOB on a windy day when upright. I have had the CG forward with a 3W200 and so far aft with a DA150 that the plane climbs when you roll inverted - but its behavior in harrier is unchanged. It stops rocking with rudder, but starts quickly after........because it is unstable in yaw at this angle of attack. Inverted it does not rock, but you must use rudder to control the roll.
Vertical fin area needs to be added to the bottom of the fusealge to stabilize an upright harrier (a la F-16). Fin area on the top of the plane is blanketed by the elevator and fuselage when the free stream airflow approaches 90 degrees and is ineffective.
3DFanatic's example is a perfect demonstration of changing yaw stablility and the result. At 30 degrees of elevator throw the airflow was not that bad over the rudder and the plane was steady. At 50 degrees, you are blocking a considerable portion of the vertical stab with a big board (the elevator), disrupting the airflow, so the configuration becomes unstable in yaw. The result - wing rock.
By the way, I mix aileron into my elevator to get the best of both worlds. Aileron in the elevator does not create gobs of adverse yaw like the ailerons do. My aileron control does work in a harrier, but not like the rudder! I use both aileron and rudder to stop the rocking too, but rudder is the primary. The harrier is an unstable position for our models to fly in.........It takes a little work to keep them there.
.........you can land a plane with no elevator (using power to control pitch), and turn it with no aileron control (using rudder to roll), and you can learn to do both very well.......but that doesn't mean you are using the best control for the job. And for you groupies, I have done both with my fanny in the seat, not reading a book or watching a video.
CJ
01-26-2004 | 11:20 AM
#23
Senior Member
Joined: Sep 2003
Posts: 205
Likes: 0
Received 0 Likes
on
0 Posts
From: Granbury,
TX
RE: wing rocking how to stop it
Chip,
I love your Ultimate! It's my 5th ultimate in a row - bought it because I shot my 52% scratch built down last summer and needed to get in the air quickly. I get harrier wing rock with all of them, though. It may have to do with the fact we fly regularly in 30+ knot winds here in TX. In calm wind it's like a big baby........
CJ
I love your Ultimate! It's my 5th ultimate in a row - bought it because I shot my 52% scratch built down last summer and needed to get in the air quickly. I get harrier wing rock with all of them, though. It may have to do with the fact we fly regularly in 30+ knot winds here in TX. In calm wind it's like a big baby........
CJ
01-26-2004 | 04:08 PM
#24
Senior Member
RE: wing rocking how to stop it
I have a Kangke Texas hurricane that will rock like crazy at idle, but if you just bump the throttle a little is will settle in a nice stable decent with 40 degrees of elevator, I have no explanation for this but it works, try it
01-27-2004 | 07:19 AM
#25
RE: wing rocking how to stop it
ORIGINAL: Blow n Go
Chip,
I love your Ultimate! It's my 5th ultimate in a row - bought it because I shot my 52% scratch built down last summer and needed to get in the air quickly. I get harrier wing rock with all of them, though. It may have to do with the fact we fly regularly in 30+ knot winds here in TX. In calm wind it's like a big baby........
CJ
Chip,
I love your Ultimate! It's my 5th ultimate in a row - bought it because I shot my 52% scratch built down last summer and needed to get in the air quickly. I get harrier wing rock with all of them, though. It may have to do with the fact we fly regularly in 30+ knot winds here in TX. In calm wind it's like a big baby........
CJ
Chip
