Wing Heavy
Wing Heavy
I have recently completed rebuilding my Aeronca 7AC and engine, they checked out great except that the plane it is very Right wing heavy. It has been suggested that the Right wing be washed in (right adjustable strut shortened) an the Left wing be washed out (left adjustable strut lengthened) I have no idea which wing strut or if either has the proper length now. Possibly only one strut needs change. It does not have a (skid ball) inclinometer installed. and yaw was corrected by seat of pants feel it possibly will need a rudder tab also. Your comments and suggestions will be appreciated N83996
Re: Wing Heavy
Do you have access to a digital level? You could use one with some spacers on it to check the angle of incidence on the bottom surface of the wing. The spacers are to give the level consistant spacing to known points on the wing like the trailing edge and a point near the main spar. You might even create spacers which bridge two ribs so you can cancel out some of the rib to rib variation.
Check at the root, mid-span, and at the end of the aileron bay and see if there are differences between wings. If so, that's probably the problem.
Check at the root, mid-span, and at the end of the aileron bay and see if there are differences between wings. If so, that's probably the problem.
Kyle Boatright
Marietta, GA
RV-6 Built and Flying
Champ Restoration Underway
Marietta, GA
RV-6 Built and Flying
Champ Restoration Underway
Re: Wing Heavy
A friend who restored a Taylorcraft BC-12D also had a heavy wing. An AD on the struts motivated him to replace his struts
and he noted that one strut was about 1 and 1/4 inches longer than the contralateral strut. Now that the struts are equal he had to remove/adjust back (many to mid-position) all the tabs and control surfaces. It may be worthwhile to check the basics first.
and he noted that one strut was about 1 and 1/4 inches longer than the contralateral strut. Now that the struts are equal he had to remove/adjust back (many to mid-position) all the tabs and control surfaces. It may be worthwhile to check the basics first.
11CC-251
Re: Wing Heavy
How did the plane fly prior to rebuilding it? If it flew nicely in the past, then you probably "built in" a problem. However, with the exception of the wings, it's hard to knock something out of whack because everything else is so simple and straight forward on a Champ.
If you started with a project plane, there is something else to check for. Bill Pancake suggested to me in the past to measure the distance between the front wing attach fitting on the fuselage and the lower strut attach fitting. When the fuselages rolled out of the factory, the distance on the left side matched the right.
Over time and many landings, the distance on the right side would tend to creep a little shorter due to the fact that the framework on the door side is not as strong as the left side. Even if your plane has no damage history, we have found almost every fuselage we have checked to have this "creep" where the door side measurement can be almost an inch shorter.
In a Cub, that's not really a problem. Piper put a forkscrew at the base of the lift strut and that is how you adjust the dihedral angle of the wings. Aeronca being the superior product with tighter tolerances didn't need the adjustment and has a fixed length lift strut. There is where the problem comes in for flying hands off in trim. If your plane has a shorter distance on the right than the left, than your left wing is sitting up a little higher than the other. The plane will try and hang evenly under level wings, but that now has the fuselage slightly crooked and the other flight controls are now cocked into the wind a little off level and the whole applecart is now upset. I know of no way to correct this without hacking into the tubing of the front fuselage which will be unheard of on a plane that has just been recovered.
For anyone rebuilding a Champ, please check the left side measurement against the right before you start building up the fuselage. If your plane has that "creep", you will be glad if you address it now rather than accept a sloppy flying plane later. Anyone who has a 7AC in pieces can have access to our fuselage jig for free to check their plane for straightness before putting on the wood and fabric.
If you started with a project plane, there is something else to check for. Bill Pancake suggested to me in the past to measure the distance between the front wing attach fitting on the fuselage and the lower strut attach fitting. When the fuselages rolled out of the factory, the distance on the left side matched the right.
Over time and many landings, the distance on the right side would tend to creep a little shorter due to the fact that the framework on the door side is not as strong as the left side. Even if your plane has no damage history, we have found almost every fuselage we have checked to have this "creep" where the door side measurement can be almost an inch shorter.
In a Cub, that's not really a problem. Piper put a forkscrew at the base of the lift strut and that is how you adjust the dihedral angle of the wings. Aeronca being the superior product with tighter tolerances didn't need the adjustment and has a fixed length lift strut. There is where the problem comes in for flying hands off in trim. If your plane has a shorter distance on the right than the left, than your left wing is sitting up a little higher than the other. The plane will try and hang evenly under level wings, but that now has the fuselage slightly crooked and the other flight controls are now cocked into the wind a little off level and the whole applecart is now upset. I know of no way to correct this without hacking into the tubing of the front fuselage which will be unheard of on a plane that has just been recovered.
For anyone rebuilding a Champ, please check the left side measurement against the right before you start building up the fuselage. If your plane has that "creep", you will be glad if you address it now rather than accept a sloppy flying plane later. Anyone who has a 7AC in pieces can have access to our fuselage jig for free to check their plane for straightness before putting on the wood and fabric.
Re: Wing Heavy
The guy who rebuilt my 7AC obviously made this mistake and the right wing droops on the ground.
At first I thought it was in the LG struts but they all measure all the same. I measured everything else except what is mentioned above so that must be my problem. Too late to change that now!!
However, it is not too hard to correct. I adjusted both wing struts a bit at a time and it now flies about hands off, as hands off as a Champ can be, which is not too much!
It does need a bit of rudder tab adjusting but that is not too hard either.
After all this it is fine for normal flying but I won't be doing any spin training in it as long as this exists!
At first I thought it was in the LG struts but they all measure all the same. I measured everything else except what is mentioned above so that must be my problem. Too late to change that now!!
However, it is not too hard to correct. I adjusted both wing struts a bit at a time and it now flies about hands off, as hands off as a Champ can be, which is not too much!
It does need a bit of rudder tab adjusting but that is not too hard either.
After all this it is fine for normal flying but I won't be doing any spin training in it as long as this exists!
Gus Causbie
Ash Flat, AR
N83564, 7AC-2235, A65-8
Ash Flat, AR
N83564, 7AC-2235, A65-8
Re: Wing Heavy
Thanks for all the comments and suggestions.
I had never considered the possibility of fuselage distortion from use or possibly hard landings, especially those you walked away from. I must admit that I may have contributed to at least one or two distortions in my 67 yrs of flying
When this airplane restoration was completed, it also sat with the right wing noticeably lower on the level hanger floor. The right outer strut measured about 1/2 inch shorter than the left (top to bottom) but this should not effect height which is controlled by the inner shock strut springs.bushings and or spacers.
A difference of .27 inch was found in the spring lengths and was corrected by the addition of a shim until a new set of springs can be obtained.The airplane sits level. We will attempt to determine if the fuselage is distorted by several measurements Distance front spar attach point to front landing gear attach point etc There were no problems found when the fuselage was stripped, checked for rust, or other problems and repainted But the suggested measurements were never thought of or considered. Thanks for your helpfulness fastmach1@windstream.net
I had never considered the possibility of fuselage distortion from use or possibly hard landings, especially those you walked away from. I must admit that I may have contributed to at least one or two distortions in my 67 yrs of flying
When this airplane restoration was completed, it also sat with the right wing noticeably lower on the level hanger floor. The right outer strut measured about 1/2 inch shorter than the left (top to bottom) but this should not effect height which is controlled by the inner shock strut springs.bushings and or spacers.
A difference of .27 inch was found in the spring lengths and was corrected by the addition of a shim until a new set of springs can be obtained.The airplane sits level. We will attempt to determine if the fuselage is distorted by several measurements Distance front spar attach point to front landing gear attach point etc There were no problems found when the fuselage was stripped, checked for rust, or other problems and repainted But the suggested measurements were never thought of or considered. Thanks for your helpfulness fastmach1@windstream.net
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Paul Agaliotis
- Posts: 2589
- Joined: Wed Dec 08, 2004 18:49
- Location: San Martin, California
- Contact:
Re: Wing Heavy
Check that your tail is on straight. All of the surfaces can be 90 degrees from each other but not square to the wings. This will induce a skid to the airplane and the leading wing will rise. I have seen many ailerons with some pretty big trim tabs. You shouldn't need one out there.
Paul
Paul
Mailing Adress : Paul Agaliotis 2060 E. San Martin, San Martin,Calif. 95046
Re: Wing Heavy
All my struts were the same length, all other measurements were the same. The two LG struts are the same and the protruding pistons are the same length.
The fuselage was level with the ground as per measured in the cockpit.
I never thought of measuring the fuselage to wing bolt mount so that has to be the only thing left unmeasured on mine.
In spite of this I now have a reasonably nice flying Champ although it is kind of embarrassing on the ground, I tell people one LG strut or a tire is low and most don't know the difference. One guy did though!!
The fuselage was level with the ground as per measured in the cockpit.
I never thought of measuring the fuselage to wing bolt mount so that has to be the only thing left unmeasured on mine.
In spite of this I now have a reasonably nice flying Champ although it is kind of embarrassing on the ground, I tell people one LG strut or a tire is low and most don't know the difference. One guy did though!!
Gus Causbie
Ash Flat, AR
N83564, 7AC-2235, A65-8
Ash Flat, AR
N83564, 7AC-2235, A65-8
Re: Wing Heavy
We did it, it was easy and it flew hands off.(as much as any 7AC). We put a tall stool under the tail, jacked the tail up until the carpenters level was level at the butt ribs (there was negligible difference between left and right wings). We then checked the level at the ribs nearest the outer end of the ailerons and changed the adjustable struts so that level readings were the same at the butt ribs and the outer aileron ribs. (no wash in, no wash out) either wing. We had to lengthen the left wing adjustable strut two turns and shorten the right wing adjustable strut four turns to accomplish this. It now fly's great and stalls power off with no tendency to choose one wing over the other. This plane was bought in one piece, but not flyable. I have no idea of how it flew before. Both rear spars were replaced on this rebuild due to mouse bites. Thanks for your suggestions and help.