The Swedish JAS 39 "Gripen", Simple and stylish

Originally posted by Zaphod58
Because canards are there WITH conventional elevators as well, which just gives you more surface for the radar to reflect off of. Canards make you more manuverable, but also are just added reflectors for radar.

You know it's not necessary to have both, right?

I'm well aware of that. But you're putting a big flat reflector near the higher point of rcs, the fuselage.

Originally posted by Zaphod58
I'm well aware of that. But you're putting a big flat reflector near the higher point of rcs, the fuselage.

And where do elevators go? Are we even speaking the same language here?

[edit on 5-8-2005 by LemonAide]

The elevators are farther back. The radar hits the fuselage first, then bounces back to the receiver. With canards, you've got an additional reflector in the front.

Originally posted by Zaphod58
The elevators are farther back. The radar hits the fuselage first, then bounces back to the receiver. With canards, you've got an additional reflector in the front.

You can point me to a source for this? This seems farfetched. In a tail chase scenario the canards would be in the "back".

Originally posted by waynos

I hope it doesn't come across as if I am stalking your threads waiting to pounce. I only wish to add information where I can.

At first it seemed so... But the longer I have been here, the more I comes clear that you wish no harm...

Cheers FMF.
Regarding this new discussion above, I'm pretty sure that just having canards instead of a tailplane does not, in itself, increase RCS overall. Having a three surface layout as used in some versions of the flanker will, I'm sure, add a large reflected surface, as stated. But if you are ditching the tail it makes no difference, in fact as reflective surfaces go a canard should be better as they are smaller than equivalen tailplanes (look at the size of the elevators on the Tornado and F-22 compared to the canards on the Rafale and Typhoon).

I'm not saying that makes the Typhoon stealthier than the F-22 (like,Duh. But someone probably WAS thinking that as they read that sentence)

I am just saying that canards are not the handicap they are made out to be.

True, and in my opinion a plane looks better with them... But that's just my personal opinion...

Originally posted by waynos
in fact as reflective surfaces go a canard should be better as they are smaller than equivalen tailplanes (look at the size of the elevators on the Tornado and F-22 compared to the canards on the Rafale and Typhoon).

From what I understand, and I've never designed with a canard, in a close coupled canard configuration the CG can be moved aft with the wing and, for an unchanged fuselage, you end up with a larger moment arm in front on which to apply your control. An all moving canard and use of the ailerons in pitch helps as well. Hence you need a smaller control surface. That's not necessarily true. Typhon and Rafale have small canards. The J-10, Viggen, and Grippen (sorta) have these huge canards. The Sukhoi's canard are an afterthought. I wouldn't call them an excellent example of canard design.

Mind you this discussion is about using canards as a control surface. WRT RCS, I would agree 100% with your post. Unless somebody can show me some hard test data to prove otherwise, of course. ;-)

That is exactly what I was getting at.

WRT the canards on thje Viggen, the reason they are bigger is because they were not meant for manoeverability and they are not all moving like the latest designs. The Viggens canards were there to give it its STOL capability and they have aileron like control surfaces along their trailing edge. The Gripens canards are a little larger than the rest in relation to aircraft size but the wing is also correspondingly smaller.

Originally posted by waynos
That is exactly what I was getting at.

WRT the canards on thje Viggen, the reason they are bigger is because they were not meant for manoeverability and they are not all moving like the latest designs. The Viggens canards were there to give it its STOL capability and they have aileron like control surfaces along their trailing edge. The Gripens canards are a little larger than the rest in relation to aircraft size but the wing is also correspondingly smaller.

Which is the same for the J-10. Like the Gripens I mean. Which makes me suspect the J-10's have short legs and compensate with large drop tanks. Basically a quick, nimble interceptor for fighting near home like the Gripens. OTOH, the big F-22 and Su-27 were designed with fighting away from home in mind.

more info :

www.abovetopsecret.com...

in teh big previous thread about the gripen

Interesting points... I am not as wise as you so I will not say anything stupid untill I study this a bit more...

Here's a photo to illustrate my point about the Viggen's fixed canards with separate control surfaces, which can be clearly seen on this pic. The Viggen wasa designed this way to give it the STOL capability which allows it to operate from sections of motorway which is a standard Swedish requirement for all their combat aircraft.



[edit on 5-8-2005 by waynos]

Nice pic... But the point in Sweden is, that just one model can take care of many things... For instance the JAS, Jakt (Hunt) Attack (Attack) and Spaning (Recognisance)...

What is the unit cost of the Gripen BTW...?????