fishtailing
05-13-2006, 04:17 PM
#4
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RE: fishtailing
the torque of the motor usualy coupled with ground effect. At the point (speed) were your control surfaces don't have enough air passing over them the engine will over come them and the plane will fishtail. acually known as a ground loop.
also a cross wind
also a cross wind
05-13-2006, 04:54 PM
#5
RE: fishtailing
Generally, a fishtailing at high speed is caused by the alternate detachment of air in the corner of the fuselage and the wing at the trailing edge. The curved fuselage causes a low pressure area and the rear part of the wing is also low pressure. Add them together and you get an area where the airflow can't stay attached. Any little disturbance causes the air on one side or the other to detach. The plane swings slightly toward the other side and that side detaches resulting in a fishtail.
This also happened on early pattern planes, in particular the Kaos where it was known as the Kaos tail dance. The fix is a large fillet to fill in the low pressure area. The same fix was used on several full scale planes.
Looks like your Spitfire has a fillet, but it may not be large enough.
You could also try a better servo or, if it really bothers you, a gyro.
This also happened on early pattern planes, in particular the Kaos where it was known as the Kaos tail dance. The fix is a large fillet to fill in the low pressure area. The same fix was used on several full scale planes.
Looks like your Spitfire has a fillet, but it may not be large enough.
You could also try a better servo or, if it really bothers you, a gyro.
05-13-2006, 06:00 PM
#6
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RE: fishtailing
The real ones do it also. Most of it has to do with the vertical fin area. We always look at it as they are wagging their tails because they are happy to be flying.
Bottom line is fly it and don't worry about it.
Bottom line is fly it and don't worry about it.
ORIGINAL: kahn41
What causes my corsair and spitfire to fishtail? It's not bad but noticeable
What causes my corsair and spitfire to fishtail? It's not bad but noticeable
05-14-2006, 03:10 AM
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RE: fishtailing
i had a pete tindal innovation that fishtailed really badly,i sorted it by going to a closed loop system on the rudder and keeping the cables very tight,the problem was caused by the original pushrods flexing whilst in flight.
05-14-2006, 11:47 AM
#9
Senior Member
RE: fishtailing
It appears the vertical is too large. It's obviously not to scale. That can create the wobble you see.
If you can live with it, it's probably not worth the trouble to change the vertical.
If you can live with it, it's probably not worth the trouble to change the vertical.
