Questions about wing designs

What are the major advantages of forward swept wings? How about canards? What advantages do they provide to combat? What about curved/sloped wing designs?

replicators
What are the major advantages of forward swept wings?

Better Aerodynamics

replicators
How about canards?

Help the aircraft turn sharper.

replicators
What advantages do they provide to combat?

Isn't it obvious, better aerodynamics=faster / Turning sharper=out maneuver the other guy.

replicators
What about curved/sloped wing designs?

- any examples, i'm not sure what your referring to.

Nice question but I am not able to write real techical answer in english. Yes, it has better aerodynamic and maneouvrability. The main principle is that the air flow is leaving the wing firstly at the end. Airflow at normal swept wing is leaving it firstly in a place next to fuselage. That means, that plane with forward swept wing can fly stabilised at higher AOA (angle of attack) and will have the lift longer. Maybe you will better understand, what I want to say, if you will see the picture from aerodynamic tunnel.

www.hitechweb.szm.sk/berkut.htm

The cannard is the way, how to produce much manueuvrability in statically unstabilized plane. Also you need a FBW (fly by wire) or FBL (fly by light) for this. For better understanding I will post a picture at Monday.

I have a strange follow-up to this question. I recently flew to Canada on an A320 and was trying to figure out why the wing was designed the way it was. This is just a little hobby I like to do when I get a window seat on my business travels. Does anyone know of a source where you can get aerodynamic information on commercial aircraft?

Originally posted by replicators
What are the major advantages of forward swept wings?

Forward swept wings bleed air off intoward the fuselage, loosing less over the tip of the wing, which
creates better airflow over the control surfaces and thus better control of the aircraft. On modern
commercial aircraft, you see winglets which also keep air over the wing instead of bleeding it off the wingtip.

Air bleeding off the wingtip creates a lot more drag and thus makes the aircraft much less efficient.

How about canards? What advantages do they provide to combat?

Canards control airflow over the wing, allowing you to virtually adjust the dynamic makeup of the wing for
better control in different circumstances, for example you want to stall the aircraft into a turn so you adjust the
airflow so it produces less lift across the wing, turning the aircraft better.

What about curved/sloped wing designs?

Depends entirely on what you mean.

Another advantage of canards is that they provide additional lift whereas a tailplane produces downforce negating a small percentage of the total lift in order to balance the plane.

The advantages of FSW have been pretty well spelt out but a negative is that the twisting forces on the wing itself are immense and there is a real danger of it twisting itself off. It can be made stiffer but this also makes it heavier wiping out some of the original advantages.

The beauty of being able to maintain a high angle of attack is that the nose of the aircraft is obviously above the actual flight path of the aircraft. In air to air combat this is important as the higher the sustained angle of attack capability, the better the opportunity to get an IR missile seeker lock, while continuing to seperate in distance from the other aircraft (most missile have a minimum target range due to arming and flight control constraints). So in plain (plane!) speak, the aircraft is travelling forward, but the nose is pointing elsewhere, hopefully towards the enemy. Flying high AOA is difficult, but the benefit of maintaining 30 degrees + of AOA is hopefully fairly clear. These days things are more complex with helmet mounted sights and highly agile IR missiles, but the theory remains the same. Hence the utility of canards. Leading edge extensions, like those seen on the F/A-18, do a similar sort of role.

About forward swept wings, what about supersonic flight? Wouldn't they cause more drag in that case?
And why can't i operational military aircraft with a low aspect wing (during WWII the xf5u solved many areodynamic problems of the wing, but the project was halted)?

Oh, Murcielago, for example the F-4's wing design. The ends of the wings are sloped up, and the horizontal stabilizers are sloped downwards.


[edit on 9-1-2005 by replicators]

Originally posted by replicators
About forward swept wings, what about supersonic flight? Wouldn't they Oh, Murcielago, for example the F-4's wing design. The ends of the wings are sloped up, and the horizontal stabilizers are sloped downwards.

The Dihedral angle does assist with lift. It is most noticeable on some STOL cargo planes.

FSW are fine for supersonic flight as evidence by both the NASA X-29 and the S-37 Berkut. The issue that was unresolved until the advent of composite material was that at high speed they developed a condition called (Ithink) aeroelastic divergence. The wings would basically twist and loose shape. Composite materials resist this

Mention of the F-4 brings to mind another question about wings. With all the many different jet fighter designs that have gone into service I can think of only two that had completely unique wing planforms unused by any other operational types, they were the F-4, of course, and the Lightning. Can anyone think of any more?

How about the Wright Flyer? I believe it's wing was an original design.

Hello.
Actualy a diehedral of a wing provides a stabilizing affect on a aircraft on the longitudinal plane. So an aircraft can be more stable but therefore less maneuvrable in respect to the roll axis of the aircraft. On the other side an anhedral "negative angle" of a wing reduces the stability but increases the maneuverability of the aircraft, wich is what we want on a fighter jet.
High wing airplanes are too much stable just for having an high wing, so in order to geting them more maneuvrable they tend to have an anehdral angle.
The F4 is called to have a pollyedral angle, and actually it had his dihedral wingtips because the first F4´s had unanticipated roll instability, so to solve the problem without remaking all the wing, they just put dihedral wingtips wich solve the problem giving them the stability they need.
A instable plane means that the pilot need to make lots of small corrections to maintain the aircraft wings leveled. I hoped i helped something.
Cheers
Paulo Bett.

Originally posted by junglejake
I have a strange follow-up to this question. I recently flew to Canada on an A320 and was trying to figure out why the wing was designed the way it was. This is just a little hobby I like to do when I get a window seat on my business travels. Does anyone know of a source where you can get aerodynamic information on commercial aircraft?

Sorry for the double post but forgot to respond to mr. junglejake.
Comercial planes like the a320 have arround a 30º swept angle wich is the optimum angle for the range of speeds that they fly that goes from arround 125knots to mach .80.
A swept wing of a comercial plane is good to fly until mach .80 but planes couldn´t have such a swept wing angle if they hadn´t flaps, a high swept wing requires a large angle of attack (angle betwen airflow and the wing mid-chord) to fly at slow speeds, so to solve that problem to fly slow such as 125 knots a plane as to extend their flaps giving them more lift with less angle of attack giving pilots a good vision for the runway and a lower stall speed.
So comercial planes are pretty much equiped with hybrid wings.
We all remember the landings of the concorde who had a super heavy mechanic nose that had to be lowered so pilots could see the runway ahead, because he had a high swept wing and low flap setting so he had to do those kind of high angles landings.

reply to post by junglejake


Another factor to wing design is lift v drag. The more curve to the top of the wing, the more lift it provides. The curve lets the airflow go smoother over the top of the wing, and the shape to the back of the wing prevents the air from being sucked off the top of the wing. But having a thick wing it also allows for structure and necessary components such as fuel tanks. The downside is that the thicker the wing, the more drag it creates. Commercial planes want as much lift as they can get, so they go for a thicker wing. Fighter type planes want more speed and maneuverability, so they go for as thin a wing as they can get.

One of the drawbacks to a standard wing is what they call a Mach Tuck. That's when they get up into the transonic range, and there is a problem with the wave drag over the top of the wing. This led to research into supercritical wings. They have a much flatter top surface, with more curve to the back of the wing. This lets them fly closer to Mach 1 without the Mach Tuck. They used this on the Boeing 777, and the AV-8B.

reply to post by waynos


SAAB J-35 Drakken?

Its about the only one I could think of.

I'd tentatively argue for the Mig25 as well, but I'm not so sure of the uniqueness of the design at the time.

You could also argue a case for the Buccaneer, as the blown wings were fairly unique?



[edit on 10/3/09 by neformore]

Not sure if you have seen this, well they have been in production for over 5 years in Russia and i am looking forward to mid 09 viewing this in real life.

reply to post by tristar


That's not a production aircraft. It was just a testbed, and never planned to go into any kind of production.

Originally posted by Zaphod58
reply to post by tristar

 

That's not a production aircraft. It was just a testbed, and never planned to go into any kind of production.

Umm...why is it they have a squadron of these ?. Not being rude or arrogant, but i have been shown a photo of a full squadron of these. But then again it may be an on going test bed, either way im looking forward to it.

reply to post by tristar


There is no squadron of them. There was a single testbed; and I'm not even sure if that's flying either.

reply to post by tristar


Because its a fake picture. It WAS marketed as a production fighter, but no one has bought it to date.

Like the X-29 though, the Su-47 was primarily a technology demonstrator, one intended to lay the foundation for the next Russian fighter. Such a fighter must not only be as advanced as the US F-22 and Eurofighter Typhoon, but must also compete for funding with the more conventional MiGs. However, Sukhoi is now attempting to market the Su-47 to the Russian military and foreign customers as a production fighter in its own right. Initial reaction was not good, but the aircraft's performance has been so impressive that the Russian government has made funds available for further testing of the design.
Still, the low budgets of the Russian military and the aircraft's high price tag make it unlikely that the Su-47 will be purchased any time in the near future.

www.flymig.com...

They've been trying to sell them since 2004, but the price has been too high for anyone to buy them.