Ventral fin for high maneuverability

For provement I have already sent someone what Chinese forth generation fighter will looks like. I please you guys notice: both two competiter of Chinese forth generation fighter would be designed to use ventral fin.
That's very interesting, if we learn a littile bite aerodynamics, we will know that as a fighter designer, who will avert to use ventral fin to cause the fighter more stable. Also, the ventral fin will lead to a bigger drag force than a design without it. So why Chinese designer such like it?
I think that ventral fin will be used for high attack angle maneuverability just same as MiG 1.44, but I guess that using way will be different. What difference will be? You guess first.

[edit on 14-12-2006 by emile]

actually you don't need a ventral fin to have better manoeuvrability, proof of these is that birds don't have one...

I think it has to do with the Chinese experience in design. I think they are not up to the level to dispose a ventral fin in their designs...

Wrong! no bird can fly over 200km/h but most jet fly over 800km/h in a to a scop. You can also see birds has no dorsal fin.

ventral fins, in the past, have always tended to be added when the designer has screwed up and not given the original design enough vertical side area, ie ventral fins were added during test flying to planes like the Jaguar, or became much enlarged compared to how they were originally intended to be such as on the F-16. Ventral fins also had to be added to the Boeing 707 and the DH Comet (when the latter became the HS Nimrod). However the advent of FBW controls rendered such crude additions unnecessary. Look at the Typhoon/Rafale/F-22 generation to see how the feature has been eradicated on the latest western designs, so a ventral fin is not evidence of advanced design but rather a lack of advanced design/control capability. The latest highly futuristic UCAV proposals have no vertical tail surfaces whatsoever.

Do you believe the ventral fin will move like this?

Image while a fighter being high attack angle, the ventral moving right to left in front view, which can contral the fighter nose turn to other direction if it not losing speed. Losing speed, yes, that is point, while fighter go for high attack angle, the dorsal fin on it where is the first place to losing speed but the ventral fin! So if you design in right way, the ventral fin could be a rudder which never losing maneuver energy.

ALso this above is image only, the layout out of chengdu aircraft factory is realy similar to, only one difference is using side airintake like F-22.
The other one out of shengyang as compeitor just looks like Su-33 with side airintake. Please notice both of them was designed as fitting vetral fin.

Cool concept, looks like a cross between a MiG-1.44 and a YF-23 to me.

Today, FBW has made the use of the ventral fin obsolete. You don't really need them anymore.

Shattered OUT...