Rafale aerodynamics

[BKNO]

Rafale Optimisation: ElementAir mon cher Watson!!!


Rafale optimisation is not a vain word or empty commercial argument.

The aircraft aerodynamic is way more developed than that of the previous design, the Rafale A.

After Rafale A flew first on 4th July 1986, it served its purpose as demonstrator, validating the close-coupled delta-canard formula.

In particular, it meet all of ACX requierements for high maneuvrability and STOL performances, climb rate, sustain dash speed etc.

The proposed Navalised version, ACM was to meet more stringuent requierement from Marine Nationale after a Carrier trial period:

Increased sink rate with a 16* AoA and better downward visibility than the A were among MN demands after Carrier trials.

Design have to evoluate further and Dassault designers didn't do things half-way.
http://img123.imageshack.us/img123/8366/rafalesaserieprofilesuppp0.jpg

The A wings were similar to that of the Mirage IIING, a crancked delta plan which allowed the A to sustain M 2.0 and provided with good qualities at high AoA.
http://img260.imageshack.us/img260/6696/awingplanjg3.jpg

In some instances (as in the case for the EAP), this wingplan can lead to assymetric dispacement of Cl at supersonic speed, the center of lift of the two parts of the wings moving back backward at a different rate. (It depends on wingsweep).

There were also gains to be made by repositioning the wings from low-shoulder to mid-fuelage and this unlocked several other design options starting with a reduction in wave drag:
http://img171.imageshack.us/img171/3229/hybridgs9.jpg

1) This allowed the designers to give the aircraft a sharply sweept LEX which not only gives an increae in lift but also is shaped for supersonic performances.

2) The surfaces of the canard was increeased by 30* and their root shaped so that they can deflect fully at 30* and increase the effect of the deflected airflow above the wing.

3) The LEX leading edge were designed sharper with a tri-dimentional shape, a constant sweept and progressive adrenal.
http://img379.imageshack.us/img379/2929/arrangementdevelopefk0.jpg

The LEX are rooted at the point where the inlets diffuser shock hits the inlet leading edge, and beneficiate from the same weaker shock wave which triggers their own while minimising its intensity.
http://img124.imageshack.us/img124/1733/vortexesdp1.jpg
At lower speeds they provoc several vortexes, one of which is clearly visible here, resulting on a significant increase in lift.

4) There was a marqued increase in wing-fuselage junction volume too, with a more blended shape which reduces wave drag and increases internal fuel volume.

Accessorly this feature is also reducing the aircraft RCS.
http://img69.imageshack.us/img69/5038/c01hybridkn3.jpg

While this would have been more than enough for most design houses, it wasn't so for the Dassault aerodynamicians.

During the Mirage 4000 flight-tests, they notices that the nose cone and front fuselage could be used to accomodate better pressure control and increase overal aerodynamic efficiency around the inlets.
http://img46.imageshack.us/img46/6490/acfareafronths5.jpg

This resulted in the characteristic V-shaped fron fuselage and inlet arrangement which optimises the airflow in front of the diffusers.
http://img296.imageshack.us/img296/1358/05rafaleb3011dn2.jpg

http://img47.imageshack.us/img47/9974/rafrontbe7.gif

This arrangement allows for a higher supersonic performances and a less complex inlet design.

But AGAIN this wasn't enough for Dassault, when they were given the word "OPTIMISEZ"!!!

Using their experience on the Mirage series they developed the conceipt of pressure and wave control even further:

Using the principes of compressive and expensive waves they channeled the boundary layer to the exact point where they wanted these phenomenons to occur: At the limit of the wing root.

There are sdeveral advantages in doing so:

First they do away with the Mirage 2000 strakes, as they are notably unstealthy and offers less control over the boundary layer.

These are normaly rooted at shoulder-level and dynamises the airflow around the fin at high AoA offering increased Yaw stability.

In the case of Rafale, by shaping the inlets in a V, they made it possible to energise BOTH that of the wing at its root and the fin's simultaneously, retain a sleek aircaft and low RCS.

http://img183.imageshack.us/img183/5148/intakeleftarrangementnh9.jpg

These shock takes place from the transonic regime, at point A where the airflow is separated, (part of it recycled by the engine IR-suppressant channel).

The shock created there is of the compressive type, and results on an increase in temperature, pressure and density, the airflow velocity becoming lower which means higher energy.

From point D and E, where it matters most, this same airflow is submited to another Shockwave, this time of the Expensive type.
http://img252.imageshack.us/img252/6682/condiii1.jpg
A new Mach line is created, resulting on lower pressures, density, temperature but a higher velocity which energises the airflow coming from the canard surfaces and the rest of the airframe.

This particular feature works so WELL thats its effects can even be seen when the aircraft is stationary due to paint tear and wear.
http://img441.imageshack.us/img441/1521/vortexeffectsairframeoq6.jpg

So to finish, the Supersonic optimisation of the wing.

Many tends to think that a 50*+ sweept angle would allow for better "performances".

Well it's true and untrue at the same time, the wing of a Mirage 2000 will drag more and have a lower lift coefficient at higher AoA.

There are advantages for higher sweept wings, higher Critical Mach is one but you need an accordingly overal reduced drag wave to take advantage of this.

For example: Mid-fuselage mounted wings and well blended fuselage wings areas, Rafale have this too...

Lower mid-to-high supersonic drag is another but this can be CONTROLED with different design features.
http://img47.imageshack.us/img47/3638/chocsli8.jpg

This is a composite image from different sources. One being NASA.

It shows the use of their little gizmo called ShockModeler and when applied to an aircraft design can bring a FEW surprises.

In the case of Rafale it appears that the designers have managed a "tour de force":

They combined the effect of both the LEX and wings shockwaves in a way that it reduces its supersonic drag where the moderate 48* sweep angle would be the most needing it = Above M 1.65.

As shown in this image, the shock wave from the LEX creates a second zone (2 in purple) ahead of the wing leading edge.
Schock_M1.674.jpg. http://img127.imageshack.us/img127/8346/schockm1674eg9.jpg
This appears from <> M 1.655 and doesn't change from M 1.8 (as shown here) to speed well in eccess of M 2.0.
Schock_M2.0.jpg. http://img171.imageshack.us/img171/7184/schockm20eq1.jpg
Before that due to their combination BOTH LEX and WING shockwaves are perpendicalar to the relative wing and are called "NORMAL".

This compresses the whole design transonic zone, and reduces its transonic and supersonic drag further = increased optimisation.

The SMART bit is that the combination of the TWO waves are hitting the JUNCTION between the LEX and the wing (Hence the LEX particular frontal design) parralel to the ambiant air from <> M 1.674, where supersonic drag gets higher.
http://img379.imageshack.us/img379/2929/arrangementdevelopefk0.jpg

This results on the creation of two other zones, one (zone 3) adopting the characteristics of the free airflow, the fourth resulting from a NEW and weaker shockwave (Expension) created by its interection with the previous.

The limit between the zones 3 and 4 is called Slip Surface and is parralel to the wing leading edge.

This artificially incereased the high mach characteristics of the main wing by lowering the pressures while increasing the airflow velocity in front of the leading edge and reducing the shock intensities... = Expansion wave AGAIN.

As a result, the LEX can bedesigned with a much higher sweep angle which if it reduces their surface doesn't result on a lower increase in LIFT, particularly so at higher Mach.

When was the last time someone asked WHY would Rafale have a higher payload and 250 nm better range with 3 X 2.000 L than a F-35 CLEAN while flying at a similar cruising speed?

Apparently, when some are buzy screwing their weight targets while CATIA, at Dassault they're buzy doing the best job an aerodynamicist can do with it and then some...

I think it's time to stop claiming superiority for somne designs which feature only (and comparatively) caterpilar-like aerodynamics.

Chapeau messieurs!!! http://img46.imageshack.us/img46/96/asterix01bu8.gif

"In Rafale the angle of attack is 16° but it can fly easily at 30° . Deck landings in the past were very stressful for the pilot. Now [in the Rafale] they are easy."
http://img402.imageshack.us/img402/6469/0630190ve9.jpg
Chief test pilot Yves Kerherve.


Enjoy.

 

[riksavage]

BKNO - And your point is?

You should seriously consider working for the French propaganda ministry. The way you defend the Rafale in all guises would, I’m convinced, ultimately result in a sale somewhere outside France!

 

[gf0012-aust]

Enjoy.

For a plane that is apparently a self evident and spectacular succes, it is amazing that it is yet to realise a Tier 1 or Tier 2 sale. (or any sale).

France is a country that is able to sell disparate but competitive systems to the Indians, Pakistanis, Chinese, Taiwanese and Americans - and yet its allegedly pre-eminent frontline aircraft is not going anywhere.....

 

[rjmaz1]

I believe the Rafale is a great aircraft its just that the industry is flooded.

Lets have a look at all the aircraft available in the 50-100 million price bracket.. we have F-16's, Gripens, Rafale, SU-35, Super Hornet, Eurofighters, F-15's and soon to be F-35. Now thats alot of aircraft to choose from.

Some countries have already been operating F-15's and F-16's for the last 20 years so they often buy newer versions for obvious reasons.

Countries like India and China have always bought Russian aircraft so its not surprising they have purchased SU-30's.

Alot of countries on a lower budget who are starting fresh would purchase teh Gripen due to its lower operating cost.

This leaves the Eurofighter and Rafale left in the European market. It seems both aircraft are similar in many area's but the Eurofighter is being selected often for political reasons.

Alot of the current Mirage owners are yet to purchase newer aircraft, when they do they may purchase the Rafale. Remember the original Mirage price bracket was 20-50 million we now have second hand F-16's and Gripens available dirt cheap.

I believe the Rafale may get a few sales next decade. Lets just hope that Russia doesn't produce an 'F-35 equivalent' as that will be very bad news for the french. That Russian aircraft will sell to many countries that the US would refuse to sell the F-35 in both Asia and the middle east.

 

[gf0012-aust]

Alot of the current Mirage owners are yet to purchase newer aircraft, when they do they may purchase the Rafale.

Existing Mirage owners also regard their platforms as having 80% of the functionality for 60-70% of the price.

Rafales problem is existing Mirage users, not F-16 or Gripen users.

 

[BKNO]

riksavage And your point is?

Be informative, the rest is your interpretation of informations, and i really dont NEED to defend it, it does it well in itself thanks...

As for the way it sells i'm not concerned by, i'm into the air element first commercials last.

gf0012-aust Existing Mirage owners also regard their platforms as having 80% of the functionality for 60-70% of the price.

They are FAR from having 50% of Rafale capabilties.

AdA chiefs reccon a single Rafale can do the job of THREE Mirages, TWO Ds and One 5F. I think they know way more about it than you dont you?

gf0012-aust Rafales problem is existing Mirage users, not F-16 or Gripen users.

Rafale problem is L-M and the US industrial weight no less than this, performance and capabilitywise, there is no Mirage nor F-16 existing at the moment that come anywhere close to it and this is proven in actual operations, not forum topics.

 

[gf0012-aust]

They are FAR from having 50% of Rafale capabilties.

AdA chiefs reccon a single Rafale can do the job of THREE Mirages, TWO Ds and One 5F. I think they know way more about it than you dont you?



Rafale problem is L-M and the US industrial weight no less than this, performance and capabilitywise, there is no Mirage nor F-16 existing at the moment that come anywhere close to it and this is proven in actual operations, not forum topics.

no doubt they do, but funnily enough thats the comment made by various french aviation staffers made to me at a conference. I guess they don't have a clue and you know more than all of us put together?

and for goodness sake, blaming LM and the might of the US industry lobby is absolutely lame. are you telling me that the french aviation industry is so incompetent (when compared to the obviously pointed inroads that french invested and participant companies like EADS, DCN, and Thales make into the international market?)

They've adopted Giats marketing team methinks.


leave your arrogance at home - unlike the others, I won't tolerate it.

 

[swerve]

...
leave your arrogance at home - unlike the others, I won't tolerate it.

I wonder - is BKNO the person otherwise known as Fonk (& a few other aliases)? The style is similar, & a couple of other things match.

 

[BKNO]

gf0012-aust I guess they don't have a clue and you know more than all of us put together?

You mean you interpret what they say the way you want it to be???

Rafale M have NO A2G capabilties whasoever, a basic RBE2 and SPECTRA, Mirage 2000-5F onboard computers etc.

Rafale F-2 have capabilties unique in NATO inventory, capable of engaging 6 A2G targets and 6 A2A targets simulatneously, with Link-16 remote targeting, backward firing of MICAs included in the package.

The A2G weapons were 250 kg kitted-up AASM (330 kg each).

So YOU know a F-16 Block with even 50% of these capabilties have you been told?

Sorry mate but for a starter i AM French (to yourdislike apparently) and can read BOTH English and French so i can ALSO tell the difference between what is said to US and what YOU understand, as well as what YOUR press report to YOU.

During the last NATO TLP they scored second A2A to USAFE F-15 while doing A2G you certainly KNOW a F-16 which have these capability i'm sure, the USAFEEagle Jockey were IMPRESSED...

gf0012-aust and for goodness sake, blaming LM and the might of the US industry lobby is absolutely lame.

Really??? There is a FULL Assemblee Nationale repport on the subject, i guess that's another one you heared of but actually never read for yourself in its original form isn't it???

Too bad i did, too bad too i dont live on assumptions and get my informations right before posting anything, (even more) too bad that i can bring the evidences of what i posted if needed.

gf0012-aust are you telling me that the french aviation industry is so incompetent (when compared to the obviously pointed inroads that french invested and participant companies like EADS, DCN, and Thales make into the international market?)

What i am saying is what the French officials are saying no more no less and if you want i'll dig the right infos for you too, i got NO problem validating what i write how about you?

As for coming up with this incompetence stuff it is not surprising considering that you put a Rafale in the same ballpark than a F-16.

gf0012-aust They've adopted Giats marketing team methinks.

Giat Marketing team is a LOT more competent than their design and production managers. Probabilly the opposite is true for Dassault.

gf0012-aust leave your arrogance at home - unlike the others, I won't tolerate it.

I have the strange feeling that what you won't tolerate is a counteridcory arguments expecially when it is sustantiated by evidences you can't moan about.

We dont have the same definitions of the word arrogance, you're a person in a position of power, i'm a free thinker with a high estime for the truth.

Sop lease leave my "arrogance" alone is and look for the rightinformations before mentioning any of my "shortcomings", even if this quote bring me a ban i'm not going to bow when i KNOW i am right it's a family tradition, sorry.

The truth is you dont get the full picture and believe what is told to you by guys restricted by their jobs weither there is NOWHERE to hide for anyone getting grilled at the Assemblee cessions appart behind the Secret-Defense Act which makes these cessions bits NOT available to the public.

This includes our AdA head of staff making these comments on the NEW capabilties available to him.

Guys like yourself and most Anglo-american writers have TWO problems, they believe everything US is better, they IGNORE the rest of the world, not my case and ho i forgot, they rely on other's for documents in a different language than English too...

Now if you want the evidences of what i was saying you just have to ask i guess it will complement what was "told to you" and then some more. Have a good day.

@swerve: When everything else failed get personal.

Another admition of failure doesn't hurt a bit (and your lot call me arrogant?) If you can't argue technically and provide with proper evidences dont insist and push it to the point where it become laughable.

Rafale aerodynamics in Military Aviation is the topic subject i take your (technical) silence for lack of argumentation, for the rest it's just the usual and i had a bvery good preview a few days ago too.

Guess why there aren't more French in your forums these days.

http://www.ec17provence.org/tlp.html

Wanna KNOW about it? Then this is the place to look for it.

 

[BKNO]

About what the French Assemblee and our ex-Defense Minister on F-35.
http://www.defencetalk.com/forums/attachment.php?attachmentid=1617&stc=1&d=1180782788

And an article from flight international...

DATE:14/06/05
SOURCE:Flight International
Europe warned on F-35 dangers
A new analysis of the European Technology Acquisition Programme (ETAP) is warning that the six-nation initiative meant to advance next-generation combat aircraft capabilities has been seriously undermined by Italian and UK participation in the Lockheed Martin-led F-35 Joint Strike Fighter (JSF) programme.

The report also says the French government-initiated Neuron unmanned combat air vehicle (UCAV) demonstration programme is not providing the industrial and technical co-ordination needed by Europe to offset US dominance in the aerospace sector.

Prepared by the Western European Union (WEU) Assembly’s technology and aerospace committee, the report says “new life” needs to be injected into the four-year-old ETAP initiative, including greater involvement of the newly established European Defence Agency in its activities. Alignment of ETAP activities with new research to be funded under the European Commission’s 2007-13 Seventh Framework is also required.

The WEU analysis says JSF programme participation by Italy and the UK ties those nations “for over a decade to a US project which makes no industrial or technological contribution to [the] European defence industrial and technology base. In research and technology terms, the issues thus raised are important ones as the sums invested in the JSF inevitably represent a loss to any other possible European project for an offensive air system of the future as envisaged in the ETAP agreement.”

 

[harryriedl]

I wonder - is BKNO the person otherwise known as Fonk (& a few other aliases)? The style is similar, & a couple of other things match.

would that be the FONK of key publishing and those memaoble flame wars on Rafael and typhoon threads

 

[gf0012-aust]

would that be the FONK of key publishing and those memaoble flame wars on Rafael and typhoon threads

I actually thought he was one of my old french buddies from SP

 

[gf0012-aust]

Sorry mate but for a starter i AM French (to yourdislike apparently) and can read BOTH English and French so i can ALSO tell the difference between what is said to US and what YOU understand, as well as what YOUR press report to YOU.

I can speak and read german and some chinese - so whats your point? My ex is French, so it appears that I don't have a problem with French women. and finally, I have the utmost respect for people like Francois as he is full bottle on the things he debates and can argue with some panache. Do I have a problem with the french - sorry to dissapoint you - but no.

Guys like yourself and most Anglo-american writers have TWO problems, they believe everything US is better, they IGNORE the rest of the world, not my case and ho i forgot, they rely on other's for documents in a different language than English too...

everything in the US is better? my my, we are making grand assumptions based on your own bigotry now. There is some French kit I like, but don't let that stop you lathering up

Guess why there aren't more French in your forums these days.

http://www.ec17provence.org/tlp.html

Wanna KNOW about it? Then this is the place to look for it.

I don't need to go to a french internet forum to get an opinion, believe it or not, we do deal with the french on a number of issues. I'll stick to my less emotional contacts thanks very much.

 

[BKNO]

gf0012-aust I can speak and read german and some chinese - so whats your point? My ex is French, so it appears that I don't have a problem with French women.

And the relevance of this is??? Let me guess you still cant read French.

gf0012-aust everything in the US is better? my my, we are making grand assumptions based on your own bigotry now. There is some French kit I like, but don't let that stop you lathering up

The only one assuming some here is you in your own atempt to turn tables.

Perhaps you can explain why then you dare saying than ANY F-16 have 80% of a Rafale capabilties when obviously this is not the case.

gf0012-aust I'll stick to my less emotional contacts thanks very much.

EEEEEEEEEEEEEER> Yes i forget, the pilots of the 1/7 Squadron are very emotional beings, they have to be for their own survival no???

MAN you got it all wrong methink...

 

[Aussie Digger]

Perhaps you can explain why then you dare saying than ANY F-16 have 80% of a Rafale capabilties when obviously this is not the case.

Try reading what he actually wrote before you start frothing at the mouth.

He stated, "Existing Mirage owners also regard their platforms as having 80% of the functionality for 60-70% of the price."

He didn't write about the F-16's capability at ALL.

And learn to play nice and drop the chip from your shoulder or you face permanent banning.

LAST WARNING.

 

[BKNO]

Mod edit:

Bye.

 

[swerve]

I actually thought he was one of my old french buddies from SP

Fonk has been banned from two of the three other fora that I frequent (Key Publishing, where Harry's seen him, & the Eurofighter forum), under different names. It was clear from what went on at the Eurofighter forum that he was known to some there from other places, so why not SP as well? I'm not sure he & BKNO are the same person, but didn't BKNO say he lives in the UK? That fits.

 

[gf0012-aust]

Fonk has been banned from two of the three other fora that I frequent (Key Publishing, where Harry's seen him, & the Eurofighter forum), under different names. It was clear from what went on at the Eurofighter forum that he was known to some there from other places, so why not SP as well? I'm not sure he & BKNO are the same person, but didn't BKNO say he lives in the UK? That fits.

Its possible, there was a common theme of national hypersensitivity and a willingness to become adversarial that made me wonder....

 

[Aussie Digger]

Fonk has been banned from two of the three other fora that I frequent (Key Publishing, where Harry's seen him, & the Eurofighter forum), under different names. It was clear from what went on at the Eurofighter forum that he was known to some there from other places, so why not SP as well? I'm not sure he & BKNO are the same person, but didn't BKNO say he lives in the UK? That fits.

Netherlands I believe he stated. Another of his comments to make himself feel superior. That he also speaks "Dutch" as well, having lived there for years.

Funnily enough I'm going there in October. I might try and track him down for a "latte"... nfloorl:

 

[Ozzy Blizzard]

Lets just hope that Russia doesn't produce an 'F-35 equivalent' as that will be very bad news for the french. That Russian aircraft will sell to many countries that the US would refuse to sell the F-35 in both Asia and the middle east.

I agree it is indeed a flooded fighter market at the moment, all with great capabilities.

If by "F35 equivelent" you mean lightweight or "low" capable fighters (in a high low mix i mean) the Russians revieled their contender in Aero india this year. The MiG 35. Upgraded R33MK 3D thrust vecored smokeless engines with around 18 tonnes of thrust. Glass cockpit, upgraded avionics and full HOTAS. Significantly increased range due to an inlarged internal fuel capacity in the dorsal tank and more fuel efficient engines. Zhuk AE AESA multimode radar and 9 hardpoints. R27EM, R77, R74 and various PGMs are on offer. Given the probable low pricetag in comparison to western contenders, this capable fighter will be very attractive to existing Fulcrum opperators and new customers alike. Supermanuverability, AESA, Mach 2+ performance, decent range, good avionics, rough field capable, impressive range of munitions at an affordable price (and dare i say it, future potential for EW/EA) is going to be verry attractive.

However any buyer will have to deal with reliability and service life issues that seem to be a problem with russian manufacturers. Nevertheless the Indians will probably have their own supprt infastructure giving any other buyers more flexability. And the new model is set to be easier to maintain than original Fulcrums and the varois current operators seem to be happy enough so i doubt this point will be much of a problem.

If this platform is as capabl;e as promised i would spend my money on it rather than an F16 or grippen and probably Raffale.