Incidences
05-11-2003 | 11:10 AM
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From: Port of Spain, FL
Incidences
Hello,
What are the symptoms of a plane which has the stab at -1 relative to the wing when it is supposed to be 0
To me this would imply that the tail would be driven down,
My plane has this incidence and the cg is about 1" fore of the manufacturer's recommendation and it still is a bit tail heavy and floaty when landing.
What are the symptoms of a plane which has the stab at -1 relative to the wing when it is supposed to be 0
To me this would imply that the tail would be driven down,
My plane has this incidence and the cg is about 1" fore of the manufacturer's recommendation and it still is a bit tail heavy and floaty when landing.
05-11-2003 | 03:18 PM
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From: St. Charles, MO
Incidences
The negative tail angle does throw an extra pitching moment into the airplane - it will tend to cause an incremental nose up pitch. Since the normal 0-0 trimmed airplane usually needs some up trim in the elevator to fly level the -1 degree will just replace this up trim but unfortunately there is usually a little excess nose up left over.
In the balance of things you can get rid of the nose up due to the incidence with a little nose down elevator trim. Mostly this will take care of it for just flying around and enjoying life.
However the incidence plus trim effects will never quite be equal to the 0 setting at all fligth conditions. If you are trying to do a precision pattern type of flying I would recommend that the incidence be removed and set to zero.
You have to be careful and try to separate the way the airplane flies due to the incidence effects and the CG effects. Look up the "dive test" in this forum to see how to locate the CG to what you would like.
Floaty when landing is really a function of wing loading, landing speed and stick held in while landing. When I land (well on a good day and when no one is there to look, when anyone is around the landing ususally are pretty bad) I drop power and feed in some up elevator - the amount of which sets the angle of attack during the landing. Excess speed and too much angle of attack will give the floaty look. Leave enough time and space for the airplane to bleed off excess airspeed. If done right you should be holding in aft stick and gradually increase it until full aft stick can be held at touchdown. Realfight is a good tool to investigate the way to do it without breaking an airplane.
In the balance of things you can get rid of the nose up due to the incidence with a little nose down elevator trim. Mostly this will take care of it for just flying around and enjoying life.
However the incidence plus trim effects will never quite be equal to the 0 setting at all fligth conditions. If you are trying to do a precision pattern type of flying I would recommend that the incidence be removed and set to zero.
You have to be careful and try to separate the way the airplane flies due to the incidence effects and the CG effects. Look up the "dive test" in this forum to see how to locate the CG to what you would like.
Floaty when landing is really a function of wing loading, landing speed and stick held in while landing. When I land (well on a good day and when no one is there to look, when anyone is around the landing ususally are pretty bad) I drop power and feed in some up elevator - the amount of which sets the angle of attack during the landing. Excess speed and too much angle of attack will give the floaty look. Leave enough time and space for the airplane to bleed off excess airspeed. If done right you should be holding in aft stick and gradually increase it until full aft stick can be held at touchdown. Realfight is a good tool to investigate the way to do it without breaking an airplane.
