V-Tail 110° vs 122°
06-06-2003, 01:32 PM
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V-Tail 110° vs 122°
Hi to everybody:
Here in México we have been flying thanks to the testing of one of the racers with 122° on the VTail instead of 110° throwing very good results on the stability of the Q500´s (428 mainly)
It calls my attention that all the planes such as the V-Max, Neme Q, Vortex and others use 110°, as we in México really have had better results with a little bit more degrees (122°)
Mainly it give us much more stability.
Could anyone comment why all the planes have 110'° or your experience using more or less degrees.
Here in México we have been flying thanks to the testing of one of the racers with 122° on the VTail instead of 110° throwing very good results on the stability of the Q500´s (428 mainly)
It calls my attention that all the planes such as the V-Max, Neme Q, Vortex and others use 110°, as we in México really have had better results with a little bit more degrees (122°)
Mainly it give us much more stability.
Could anyone comment why all the planes have 110'° or your experience using more or less degrees.
06-06-2003, 05:08 PM
#2
Just an observation
Any time you flatten V tail (120 degrees) without changing the tail moment arm you will increase stability around the lateral axis while at the same time will be reducing stability around the vertical axis.
If you make it less of an angle (100 degrees earlier Preditors, done I think to make it easier to stuff in the box) without changing the tail moment arm you are reducing stability around the lateral axis while at the same time you will increase stability around the vertical axis.
everything is a compromise
John
If you make it less of an angle (100 degrees earlier Preditors, done I think to make it easier to stuff in the box) without changing the tail moment arm you are reducing stability around the lateral axis while at the same time you will increase stability around the vertical axis.
everything is a compromise
John
06-09-2003, 01:26 PM
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V-Tail 110° vs 122°
Thanks a lot John, thats a quite professional answer.
Might these be the cause that when we turn arrond Pylons the plane tends to lower down the V Tail a little?
These effect has been observed in these Q500's in which we have flattened the V.Tail but not in the ones with 110 Degrees.
Might these be the cause that when we turn arrond Pylons the plane tends to lower down the V Tail a little?
These effect has been observed in these Q500's in which we have flattened the V.Tail but not in the ones with 110 Degrees.
06-09-2003, 10:32 PM
#4
V-Tail 110° vs 122°
Thanks oddy
Keeping in mind I am no engineer, there is another factor in the mix here and that is the moment arm of the tail (both the vertical and horizontal stabilizing area). In other words the distance the tail is behind the CG (or more properly the neautral point) The longer that arm the more stability for both the yaw and pitch axis.
Engineers use a referrance number that I believe is called the tail volume and it is the product the horizontal stabilizer area including control surface times the moment arm. In the case of a 'V' tail that actual horizontal tail area is what you actually see when looking straight down on top of the V tail. The Vertical tail area is actually what you see when looking straight from the side times two.
Now to my way of thinking I think the perfect situation for our application is for the vertical tail volume and the horizontal tail volume to match very closely. I Believe that when you have the situation where the pitch stability is a higher tail volume number than the yaw stability it will expose itself when you pull high 'G's at the #1 by doing a little 'Butt wiggle' and that robs acceleration out of the pylon.
Now to 'play the devils advocate' while acheiveing good stability around all axis' is a good thing to a point. Too much stability particularly on the pitch axis will reduce the the airplanes ability to make a very tight radius turn without loosing excessive speed. So were right back to the old compromise affecting the next compromise and affecting the next compromise so on. But certainly is interesting Huh.
All of the above is just my personnel speculation and I claim neautrality under the articals of war when the aerodynamics soldiers come after me with their weapons at the ready.
John
Keeping in mind I am no engineer, there is another factor in the mix here and that is the moment arm of the tail (both the vertical and horizontal stabilizing area). In other words the distance the tail is behind the CG (or more properly the neautral point) The longer that arm the more stability for both the yaw and pitch axis.
Engineers use a referrance number that I believe is called the tail volume and it is the product the horizontal stabilizer area including control surface times the moment arm. In the case of a 'V' tail that actual horizontal tail area is what you actually see when looking straight down on top of the V tail. The Vertical tail area is actually what you see when looking straight from the side times two.
Now to my way of thinking I think the perfect situation for our application is for the vertical tail volume and the horizontal tail volume to match very closely. I Believe that when you have the situation where the pitch stability is a higher tail volume number than the yaw stability it will expose itself when you pull high 'G's at the #1 by doing a little 'Butt wiggle' and that robs acceleration out of the pylon.
Now to 'play the devils advocate' while acheiveing good stability around all axis' is a good thing to a point. Too much stability particularly on the pitch axis will reduce the the airplanes ability to make a very tight radius turn without loosing excessive speed. So were right back to the old compromise affecting the next compromise and affecting the next compromise so on. But certainly is interesting Huh.
All of the above is just my personnel speculation and I claim neautrality under the articals of war when the aerodynamics soldiers come after me with their weapons at the ready.
John
