help on balancing low wing planes
11-05-2012, 02:50 PM
#51
Senior Member
RE: help on balancing low wing planes
ORIGINAL: Bozarth
da Rock (I still don't know your real name),
I applaud your diligence. But it falls under the TLAR method if you apply science to part of the equation, and experience to the other. Specifically, how are you determining what the coefficient of lift is for your wing and tail? Or the wing's pitching moment coefficient? My guess is you are estimating. Which then leads to an estimated SM, which then leads to an estimated desired CG location. Which I would bet, falls somewhere between 25 to 35% of the MAC.
How do you learn of these coefficients for ARFs? I bet you estimate based on your experience. And I bet you know how it should feel when you fly it. And I bet you recognize there is a trade-off between maneuverability and stability, etc.
There is no ''correct'' cg provided it is within the static margin.
Measuring a cg location to the nearest 1/16'' means nothing. How do you like how the plane flies?
Measuring the cg to the nearest nth degree is like measuring how much hair the barber cut off.
Kurt
da Rock (I still don't know your real name),
I applaud your diligence. But it falls under the TLAR method if you apply science to part of the equation, and experience to the other. Specifically, how are you determining what the coefficient of lift is for your wing and tail? Or the wing's pitching moment coefficient? My guess is you are estimating. Which then leads to an estimated SM, which then leads to an estimated desired CG location. Which I would bet, falls somewhere between 25 to 35% of the MAC.
How do you learn of these coefficients for ARFs? I bet you estimate based on your experience. And I bet you know how it should feel when you fly it. And I bet you recognize there is a trade-off between maneuverability and stability, etc.
There is no ''correct'' cg provided it is within the static margin.
Measuring a cg location to the nearest 1/16'' means nothing. How do you like how the plane flies?
Measuring the cg to the nearest nth degree is like measuring how much hair the barber cut off.
Kurt
11-05-2012, 03:16 PM
#53
RE: help on balancing low wing planes
ORIGINAL: da Rock
The written word is about the worst communications us humans flog each other with.
What at least one of the most ''opinionated people'' has for motives is to provide enough detail that every beginner who comes through this swamp doesn't leave with just wet feet.
The point is for everyone to have a chance to understand most of this isn't an individual's opinion, and to understand how to find the mfg's suggested CG location with sufficient accuracy.
The written word is about the worst communications us humans flog each other with.
What at least one of the most ''opinionated people'' has for motives is to provide enough detail that every beginner who comes through this swamp doesn't leave with just wet feet.
The point is for everyone to have a chance to understand most of this isn't an individual's opinion, and to understand how to find the mfg's suggested CG location with sufficient accuracy.
All the OP wanted to know is why the airplane needed to be balanced up-side-down, and if the nose needed to point up or down. The techniques and aeronautical terms could have been left out. Now it is really confusing for anybody trying to read thru this mess.
Rafael
11-05-2012, 03:27 PM
#54
My Feedback: (15)
RE: help on balancing low wing planes
ORIGINAL: Rafael23cc
I _may_ understand your motives. The questions is, was it really necessary? The questions asked was simple and the answers would have been simple enough for anybody to understand. Now we are going into MAC and other parameters that would glaze over a newbie's eyes.
All the OP wanted to know is why the airplane needed to be balanced up-side-down, and if the nose needed to point up or down. The techniques and aeronautical terms could have been left out. Now it is really confusing for anybody trying to read thru this mess.
Rafael
ORIGINAL: da Rock
The written word is about the worst communications us humans flog each other with.
What at least one of the most ''opinionated people'' has for motives is to provide enough detail that every beginner who comes through this swamp doesn't leave with just wet feet.
The point is for everyone to have a chance to understand most of this isn't an individual's opinion, and to understand how to find the mfg's suggested CG location with sufficient accuracy.
The written word is about the worst communications us humans flog each other with.
What at least one of the most ''opinionated people'' has for motives is to provide enough detail that every beginner who comes through this swamp doesn't leave with just wet feet.
The point is for everyone to have a chance to understand most of this isn't an individual's opinion, and to understand how to find the mfg's suggested CG location with sufficient accuracy.
All the OP wanted to know is why the airplane needed to be balanced up-side-down, and if the nose needed to point up or down. The techniques and aeronautical terms could have been left out. Now it is really confusing for anybody trying to read thru this mess.
Rafael
Party pooper........oh, wait. Go Chiefs.
11-05-2012, 04:11 PM
#55
RE: help on balancing low wing planes
"All the OP wanted to know is why the airplane needed to be balanced up-side-down, and if the nose needed to point up or down. The techniques and aeronautical terms could have been left out. Now it is really confusing for anybody trying to read thru this mess.
Rafael"
If the OP's eyes glaze over at this point (25 years operating and building acccording to his profile) he needs cataract surgery. He isn't a newbie and newbies can benefit from the exchange of ideas.
Bob
Rafael"
If the OP's eyes glaze over at this point (25 years operating and building acccording to his profile) he needs cataract surgery. He isn't a newbie and newbies can benefit from the exchange of ideas.
Bob
11-06-2012, 03:34 PM
#57
RE: help on balancing low wing planes
ORIGINAL: retransit
''All the OP wanted to know is why the airplane needed to be balanced up-side-down, and if the nose needed to point up or down. The techniques and aeronautical terms could have been left out. Now it is really confusing for anybody trying to read thru this mess.
Rafael''
If the OP's eyes glaze over at this point (25 years operating and building acccording to his profile) he needs cataract surgery. He isn't a newbie and newbies can benefit from the exchange of ideas.
Bob
''All the OP wanted to know is why the airplane needed to be balanced up-side-down, and if the nose needed to point up or down. The techniques and aeronautical terms could have been left out. Now it is really confusing for anybody trying to read thru this mess.
Rafael''
If the OP's eyes glaze over at this point (25 years operating and building acccording to his profile) he needs cataract surgery. He isn't a newbie and newbies can benefit from the exchange of ideas.
Bob
ORIGINAL: Bozarth
Party pooper........oh, wait. Go Chiefs.
Party pooper........oh, wait. Go Chiefs.
Rafael
11-07-2012, 07:36 AM
#59
RE: help on balancing low wing planes
ORIGINAL: Rafael23cc
You'd be horribly surprised with some of people I have encountered in the 20+ years of me being in this hobby. They are quite content with what they know, and could care less about the rest.
I spend my time at the field or learning about my hobby, not watching grown men running around.
Rafael
ORIGINAL: retransit
''All the OP wanted to know is why the airplane needed to be balanced up-side-down, and if the nose needed to point up or down. The techniques and aeronautical terms could have been left out. Now it is really confusing for anybody trying to read thru this mess.
Rafael''
If the OP's eyes glaze over at this point (25 years operating and building acccording to his profile) he needs cataract surgery. He isn't a newbie and newbies can benefit from the exchange of ideas.
Bob
''All the OP wanted to know is why the airplane needed to be balanced up-side-down, and if the nose needed to point up or down. The techniques and aeronautical terms could have been left out. Now it is really confusing for anybody trying to read thru this mess.
Rafael''
If the OP's eyes glaze over at this point (25 years operating and building acccording to his profile) he needs cataract surgery. He isn't a newbie and newbies can benefit from the exchange of ideas.
Bob
ORIGINAL: Bozarth
Party pooper........oh, wait. Go Chiefs.
Party pooper........oh, wait. Go Chiefs.
Rafael
After informing a fellow flier about the care and feeding of Rx batteries on several occasions, he subsequently goes and flies and has a fly away. Dollars to doughnuts, the battery gave up the farm. I can't prove it because the plane is lost somewhere. On another occasion another flier was heard to say on a video that his batteries were at minimal voltage and that was good enough. After having his throttle stuck full open, he proceeds to fly around using up his batteries by performing maneuvers until he runs out of fuel. The batteries won that race. The result was a full bore lawn dart into the the earth. Another flier crashes when his plane is obviously tail heavy, fails to recognize the symptoms and continues to keep the aircraft aloft until he can no longer sustain any kind of control.
Fifty-five years in the hobby and no, I can't be surprised anymore. Talking to these people is fruitless.
Bob
11-07-2012, 09:48 AM
#60
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RE: help on balancing low wing planes
retransit,
You are starting to sound like Tired Old Man.
You know everything, and can't tolerate the ignorance of your peer group.
Greg
You are starting to sound like Tired Old Man.
You know everything, and can't tolerate the ignorance of your peer group.
Greg
11-07-2012, 02:25 PM
#61
RE: help on balancing low wing planes
ORIGINAL: OldRookie
retransit,
You are starting to sound like Tired Old Man.
You know everything, and can't tolerate the ignorance of your peer group.
Greg
retransit,
You are starting to sound like Tired Old Man.
You know everything, and can't tolerate the ignorance of your peer group.
Greg
Rafael
11-07-2012, 02:50 PM
#62
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RE: help on balancing low wing planes
I never mentioned stupidity. Don't add things I didn't mention.
My original observation of your comments on this post still reflect your personality.
Still standing by my original comment.
Just saying...Ha.
Greg
My original observation of your comments on this post still reflect your personality.
Still standing by my original comment.
Just saying...Ha.
Greg
11-07-2012, 06:11 PM
#63
RE: help on balancing low wing planes
ORIGINAL: OldRookie
retransit,
You are starting to sound like Tired Old Man.
You know everything, and can't tolerate the ignorance of your peer group.
Greg
retransit,
You are starting to sound like Tired Old Man.
You know everything, and can't tolerate the ignorance of your peer group.
Greg
I can stand the ignorance. We learn from other's experience and knowlege, and that includes me as the student. What I cannot tolerate is a mind set where a bit of attention to detail will defuse a bad situation concerning a fundamental safety issue. If you want to crash your plane due to unsafe practices, go ahead, but don't do it with others around and in a setting that can have a detrimental effect on those people.
Bob
11-09-2012, 08:51 AM
#66
Join Date: Dec 2001
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RE: help on balancing low wing planes
Hi!
Long fingers???
What do mean? Just hold the fingers under the wing at the supposed C of G What could be more difficult?
If the plane sits okay go out and fly it! If it doesn't behave good...change the C of G (Move servos and batteries )and go out and fly again. Repeat this process untill you are satiesfied with the flight caracteristics.
Long fingers???
What do mean? Just hold the fingers under the wing at the supposed C of G What could be more difficult?
If the plane sits okay go out and fly it! If it doesn't behave good...change the C of G (Move servos and batteries )and go out and fly again. Repeat this process untill you are satiesfied with the flight caracteristics.
11-09-2012, 01:28 PM
#67
RE: help on balancing low wing planes
My answer to that is, get it right the first time and you won't have to move components. Even if you do, it can be limited to a battery pack, which is easy to do. Servos require changing mounting location and pushrods if you want to fly to confirm your CG choice.
I've said it before, but it bears repeating. It is difficult to hold a 23lb. plane with two fingers, especially if it is covered with fabric. I wouldn't want to place that concentrated force on the fabric. That is why I use the hook, cord and plumb bob. By using a balancing device, no matter what it is, you can move components while on the balancer.
Bob
I've said it before, but it bears repeating. It is difficult to hold a 23lb. plane with two fingers, especially if it is covered with fabric. I wouldn't want to place that concentrated force on the fabric. That is why I use the hook, cord and plumb bob. By using a balancing device, no matter what it is, you can move components while on the balancer.
Bob
