F-16.net

Enthusiast Joined: Dec 07, 2006 Posts: 28 Status: Offline

Kind of interesting. Didn't know that Korea was actually building fighters.

http://www.militaryphotos.net/forums/sh ... hp?t=89427

http://youtube.com/watch?v=PVw1X2iYrnE

F-16.net Sponsor

tiedyed wrote:

Kind of interesting. Didn't know that Korea was actually building fighters.

http://www.militaryphotos.net/forums/sh ... hp?t=89427

http://youtube.com/watch?v=PVw1X2iYrnE

Umh, they already build F-16s...

In all seriousness, in stealth design more than any other, the devil is in the details. Making something LOOK stealthy is not at all making something actually stealthy. Sorry if I don't make much sense tonight... have had to much Chivas! Cheers

::Edited by mod for intollerant statements::

Enthusiast Joined: Mar 08, 2005 Posts: 49 Status: Offline

Does KAI's F/A-50 count? Smile

Elite 1K Joined: Aug 01, 2006 Posts: 1003 Status: Offline

There is a big misconception that Canard layouts are better than Horizontal Tail layouts -- in part due to its popularity with the last few iterations of 4th genration fighters. The canard layout is neither more efficient nor does it provide superior control authority in most respects. Had the former been true, fuel miserly Boeings and Airbuses will be canards. In aerodynamically stable designs the canards are able to compliment the wing as lifting surfaces. But in unstable designs, both canards and tails do that. Canards have all kinds of problems not found on Wing-tail designs. The biggest being that the center of lift form the main wing is much further aft than is ideal -- ideal being close to the geometric and gravitational centers of the aircraft. This leads to trim inefficiencies, a problem which is worsened when the wing also carries heavy ordnance and fuel. The generally sharper, wide chord deltas also require higher AoAs at landing speeds, is somewhat less efficient at subsonic cruise and reduce the amount of underwing room for stores.

The biggest advantages of canard designs are two fold. The first being that they allow the wider span main wing to be further aft and hence is able to tuck it within a more acute shock cone. If you push Mach 3 (remember the XB-70?) that may be a significant advantage, but for Mach 1.8~2 fighters like we see them on, that is largely irrelevant. The second thing being that the vortex from the canards improve the high alpha vortex lift performance of the main wing -- the canard vortexes go over the main wing whereas the tail vortex go over nothing. However, LEX have the same effect and more recently very refined designs like the F-35 and F-22 rely on multiple complimentary vortexes to achieve the same thing without awkward and draggy LEXes. In any case, none of this is particularly relevant until very high AoAs (>20 degrees) are being pulled. And in combat with jets going ~Mach 1 or faster, G-loading limits of 7~12Gs limit AoA to much less than that meaning all of those Cobra and High Alpha tail stand pass enabling capabilities are largely irrelevant.

Below image shows the complimentary interaction of three vortexes. The nose vortex (not labeled but visible as a red line) merges with, and is pulled outwards slightly by, the lip vortexes from the intakes. The resulting strengthened vortex then merges with the wing vortex and is pulled outwards further more to cover the largest possible wing surface before exloding clear of the vertical tails so as not to buffet it. The resultant vortex maginitudes and coverage charateristics is better than I have seen from any LEX or canard based designs so far.

The F-35 follows a similar -- nose, lip and wing -- complimentary vortex principle.

SWERC.Com is the Sung Woo Engineering Corporation - they make model aircraft, baby UAV's and target drones.

Korean Air started the local aircraft industry in the mid 70's.

F-16.net Editor Joined: Sep 23, 2003 Posts: 2862

Depends what you are using a canard for.

In the case of the old Kfir, fixed canards were a help to aid in shorter take off rolls on a hot day with a heavy bombload.

Canards help the naval variant of the big SU so as to do a slower approach speed.

The take-off and landing advantages mentioned may also help a canard Flanker variant get into and out of shorter fields when loaded up. I don't know but the theory would have to be told to me by an engineer.

Just all depends what you are trying to do. I think if the goal is super manuverability, it is a complete waste of time as high off-boresight HOBS heaters end that advantage real quick.

As a maintenance item. If the goal is the idea of super manuver forget it, waste of time. Just one more item on an air frame ( like swing wings )... that has to be maintained, inspected, refirb'd. ......= extra cost over the life of the jet. "#0013 is down, can't find a spare part for the canard...."

Why go out of the way to make things so GD complex if it isn't needed?

I'm looking at the small size of that Korean vaporware and seeing the two mouths to feed and thinking that the legs are going to be aweful short. Where is the internal fuel going to go? Better get a legacy Hornet driver to advise you on time management for missions. Laughing

F-16.net

Forum: F-35 Lightning II

Hyundai and Kia's Version of the F-35