ADA Tejas (LCA) News and Discussions

[ersakthivel]

chinese removed canards of j20 after finding that it gives way higher rcs
.
and ada never applied canard to mca
.
so this proves the stupidity of those who calling ada as stupid on design creation
.
ada also tested canard on tejas but found that it doesn't multiply force but actually increase rcs
.

chinese removed canards on j-20?
please check.

 

[abhi_the _gr8_maratha]

chinese removed canards on j-20?
please check.

sorry , wrote it wrongly
.
let of correct myself
.
chinese used canards on j20 for more force and speed but while testing they found that it gives way higher rcs, may be j20 was detected while test by radar
.
so to correct this mistake , there is no canards on j31
.

 

[ghost]

 

[makmohan]

2566th flight on 09 May
TD1 : 233 PV1: 242 PV3: 381 LSP1: 74 LSP3: 200 LSP5: 267 TD2 : 305 PV2: 222 PV5: 40 LSP2: 294 LSP4: 114 LSP7: 94 NP1: 22 LSP8 : 78

2543th flight on 29 April
TD1 : 233 PV1: 242 PV3: 381 LSP1: 74 LSP3: 200 LSP5: 259 TD2 : 305 PV2: 222 PV5: 40 LSP2: 294 LSP4: 110 LSP7: 85 NP1: 21 LSP8 : 77

In 10 days - 23 flights.. not bad looks like fast tracking for meeting the FOC schedule..

 

[ersakthivel]

Well, or fake experts are once again hitting the wailing wall iwth the supposed superiority of grippen A/B/C?D over tejas mk-1!!!

First things first.
grippen max take off weight is 14 tons , but no one knows what is the MTOW for indian hot weather conditions.

can any one really certify how much was grippen C/D's max take off weight is in indian hot and humid conditions? No one has done that. but for tejas it was certifies to be 13.2 tons in indian hot weather conditions with the humidity in air very diferent from cold climatic nations.

Why I want to know this is that the hot climate generally reduces Max take off weight of any fighter because the jet engine thrust drops in these conditions.Without knowing this just looking at brochure specs is of no use.

Also grippen C/D weighs 300 kg more than tejas mk-1 in empty,

so a what ever marginal weapon load advantage enjoyed by grippen C/D is of no use because its excess empty weight offsets the marginal extra max take off weight.

This fact is often forgotten by fake experts spewing bile. And grippen C/D has no excess internal fuel capacity over tejas mk-1. In fact if some reports are to be believed it is supposed to have 20 percent lesser internal fuel capacity than tejas mk-1.

So in no way grippen C/Dis going to have more combat range in indian hot weather combat conditions while lifting any useful combat load.Whatever people claim!!!

And grippen' bit smaller delta wing with a bit higher wing loading and a bit lower internal fuel capacity,

was essentially built for the sweedish climatic conditions , where the engine thrust and wing lift wont suffer due to very high summer temp as in indian hot climate.

Also it has been explained to these bots a hundred times that F-16 XL which has a way higher wing area over F-16 (exactly like tejas airframe for all practical purpose!!!) suffers no drag penalty and and lifts more combat load and reaches a much higher combat range and outdoing the smaller wing area , high wing loading F-16 in almost all combat parametes including climb rate, g onset rate, etc, etc,

I am tired of repeating this again and again, because I have posted the link below at least twenty times,


. But these bots dread to acknowledge this inconvenient fact, because it will straight away puncture their "tejas bigger wing produces more drag theory".
In the above link it has been clearly explained that ,

The Revolutionary Evolution of the F-16XL

he Revolutionary Evolution of the F-16XL

By F. Clifton Berry, Jr.

This dual role fighter candidate has one foot in the present ad one foot in the future.
When Lt. Gen. Lawrence A. Skantze spoke at the rollout of the first F-16XL on July 2, 1982, he was speaking in his then-role as Commander of Aeronautical Systems Division. He characterized ASD's perspective as having "one foot in the present and one foot in the future."

Looking to the future, General Skantze said that "somewhere out there is a new and advanced technology fighter," and that sometime soon, USAF's present exploratory work would lead to the definition of that new aircraft. Meantime, he said, it's "our responsibility to take the fighter craft we have today and evolve those into higher performers, better performers, and improve their margin and hone the edge of their cutting abilities as the future goes before us."


That has been accomplished in the F-16XL. In a cooperative program, General Dynamics and the Air Force have demonstrated that, at rather modest cost, the F-16XL delivers double the range or payload of the current impressive F-16 performance.


That is revolutionary evolution indeed. The story of how it came to pass is an excellent illustration of industry initiative and risk-taking being applied to US Air force needs, with USAF taking a share of the costs in order to capitalize on the advances created. The result if the aircraft is chosen for production of up to 400 copies for USAF, will be a low-risk, high-payoff for the taxpayers.


D. Randall Kent is Vice President and Program Director for the General Dynamics F-16XL program that involved a team of more than 600 specialists. He summarizes the XL program this way:


"The F-16XL flight-test program has conclusively demonstrated that the XL performs as predicted. This performance level represents a significant increase in mission capability for USAF. Coupling this with the affordability and low risk of the F-16XL presents USAF with a viable way to increase mission capability while simultaneously growing to a forty-wing TAC force structure."


In addition to its potential as USAF's derivative fighter, the F-16XL is reportedly being considered by the Japanese Air Self-Defense Force as a replacement for its current ground-attack aircraft. Also, because of its extended range, payload, and suitability for both ground-attack and air-to-air roles, the F-16XL is a prime candidate for US maritime defense operations. That option is now being studied by defense officials and is yet another example of blending USAF and US Navy capabilities to enhance defense performance.


Genesis of the F-16XL


When General Dynamics won the LWF competition with the YF-16, David Lewis, the company's Chairman and Chief Executive Officer, looked ahead. Among other decisions, Lewis set GD's designers to work to develop derivatives of the F-16.


Harry J. Hillaker was chief project engineer for the advanced versions of the F-16. Harry has been involved in the advanced design of every major aircraft produced at Fort Worth since 1942. He served as YF-16 deputy chief engineer and director of F-16 deputy chief engineer and director of F-16 marketing before turning to leading the F-16XL design effort. The advanced designs that led to the F-16XL were undertaken with company funds and with the cooperation of the National Aeronautics and Space Administration (NASA) and USAF.


Hillaker said that the objective of the F-16XL program was to achieve a logical evolution from the basic F-16 that would provide significant improvements in all mission performance elements. At the same time, it would retain the fundamental F-16 advantage of low procurement and operating costs.

Although the principal improvements were to be in range and payload capabilities, simultaneous improvements in all other mission elements were to be given equal emphasis.

For example, survivability was to be a prerequisite to longer range. Higher military power (non-afterburning) penetration speed, lower observables, increased maneuver agility, and reduced vulnerable area increased the survival rate so as to be consistent with a longer-range/deeper-penetration capability.


To say that Hillaker's design team achieved its objectives is an understatement. Example:

For an air-to-surface mission,

1.the F-16XL can carry twice the payload of the F-16A

2.up to forty-four percent farther,

3.and do it without external fuel tanks while carrying four AMRAAM (Advanced Medium-Range Air-to-Air Missiles) and two Sidewinder AIM-9 infrared missiles.

4. With equal payload/weapons and external fuel, the mission radius can be nearly doubled.

5.When configured for a pure air-to-air mission, an F-6XL with four AMRAAMs and two AIM-9s can go forty-five percent farther than an F-16A and can do so while conducting a combat action that is equal to thirty percent of its internal fuel.

6.As for penetration and survivability, the F-16XL can dash supersonically with a load of bombs at either high or low altitude. It can climb at high rates with the bombs aboard.

7.And it has a speed advantage of up to eighty-three knots over the F-16A at sea level at military power setting and 311 knots on afterburner at altitude while carrying a bomb load.


8.Two additional capabilities of the F-16XL contribute to survivability. First is improved instantaneous maneuver ability coupled with greatly expanded flight operating limits (with bombs),

9.and second is reduced radar signature resulting from the configuration shaping.



Importance of High Turn Rate


For a decade and a half, many fighter tacticians have stressed the paramount importance of being able to sustain a high turn rate at high Gs. The rationale was that with such a capability, enemy aircraft that cannot equal or better the sustained turn rate at high Gs could not get off a killing shot with guns or missiles.

With developments in missiles that can engage at all aspects, and as a result of having evaluated Israeli successes in combat,

the tacticians are now leaning toward the driving need for quick, high-G turns to get a "first-shot, quick-kill" capability before the adversary is able to launch his missiles.

This the F-16XL can do. Harry Hillaker says it can attain five Gs in 0.8 seconds, on the way to nine Gs in just a bit more time.

That's half the time required for the F-16A, which in turn is less than half the time required for the F-4. The speed loss to achieve five Gs is likewise half that of the F-16A.


All of these apparent miracles seem to violate the laws of aerodynamics by achieving greater range, payload, maneuverability, and survivability. Instead, they are achieved by inspired design, much wind-tunnel testing of shapes, exploitation of advanced technologies, and freedom from the normal contract constraints.


The inspired design mates a "cranked-arrow" wing to a fifty-six inch longer fuselage. The cranked-arrow design retains the advantages of delta wings for high-speed flight,

but overcomes all of the disadvantages by having its aft portion less highly swept than the forward section. It thus retains excellent low-speed characteristics and minimizes the trim drag penalties of a tailless delta.




Although the wing area is more than double that of the standard F-16 (633square feet vs. 300 square feet), the drag is actually reduced.

The skin friction drag that is a function of the increased wetted (skin surface) area is increased,

but the other components of drag (wave, interference, and trim) that are a function of the configuration shape and arrangement are lower,

so that the "clean airplane" drag is slightly lower during level flight, and forty percent lower when bombs and missiles are added.

And although the thrust-to-weight (T/W) ratio is lower due to the increased weight, the excess thrust is greater because the drag is lower – and excess thrust is what counts.


The larger yet more efficient wing provides a larger area for external stores carriage. At the same time, the wing's internal volume and the lengthened fuselage enable the XL to carry more than eighty percent more fuel internally. That permits an advantageous tradeoff between weapons carried and external fuel tanks.


Through cooperation with NASA, more than 3,600 hours of wind-tunnel testing refined the shapes that Harry Hillaker and his designers conceived. More than 150 shapes were tried, with the optimum design now flying on the two aircraft at Edwards.


As an additional technology, the XL's wing skins are composed of an advanced graphite composite material that has a better strength-to-weight ratio than aluminum, is easier to form to the compound wing contours, and has higher stiffness to reduce undesirable flexibility effects.


Proof is in the Flying


The aircraft was loaded with twelve Mk 82 50-pound general-purpose bombs, four dummy AMRAAM missiles, and two AIM-9 Sidewinder missiles. Internal fuel was 10,200 pounds (full fuel for the prototype is 10,600 pounds). Allowing for fuel consumption for engine start and taxi, gross takeoff weight was 43,500 pounds. Jim estimated the takeoff roll at a bit more than 3,000 feet.



The F-16 design has always impressed me. It looked functional yet appealing, a design already in the classic category. Approaching the F-16XL with an F-16 alongside reinforced the appeal. Just parked on the ramp, the airplane looked efficient, and you wanted to get in and fly to see what it will do. The walk-around inspection reinforced the feeling, and verified features of the XL design discussed earlier.


Of particular interest were the control surfaces on the aft edge of the cranked-arrow wing. The F-16XL does not have a horizontal tail. Thus, the control surfaces for both pitch and roll are on the rear edge of the wing. The inboard surfaces are mainly for pitch control, while the out board surfaces take care of roll control. However, thanks to the automatic flight control system, when performance requires it, all four surfaces can act in either pitch or roll.


Supersonic in Seconds


Takeoff from Edwards AFB's Runway 22 with maximum power at gross weight of 43,500 pounds was achieved in les than 3,000 feet. Jim eased back the power to climb away from the Edwards traffic pattern and take up a northerly heading for the test airspace assigned to us.


Cleared to climb to 30,000 feet, Jim applied afterburner and back pressure. Our weight was diminished only by the fuel used for takeoff and the brief excursion out of the pattern.

We climbed at more than 20,000 feet per minute, leaping from 4,000 to 27,000 feet in sixty-seven seconds. Jim eased the power back while turning into the supersonic corridor and getting cleared by Edwards Control to begin a supersonic run.

Jim applied afterburner and the aircraft accelerated smoothly from Mach 0.95 through 1.0 and to 1.2 in seconds. Even with the heavy bomb load aboard, the aircraft went supersonic without a tremble. Handling characteristics at mach 1.2 with the heavy ordnance load were remarkably similar to those of the standard F-16 without bombs.


Jim pulled the throttle back to military power. The aircraft continued to coast supersonically for a long period before the mach meter showed that we were once again subsonic at 0.97.


Next, we maneuvered at slow flight speeds and high angles of attack, demonstrating the F-16XL's agile handling in that corner of the performance envelope. With airspeed below 150 knots, Jim invited me to try a roll to the left. Pressure on the side-stick controller resulted in a fast roll, with no sensation of lagging because of the heavy payload. Release of pressure stopped the roll immediately. I tended to "ratchet," and tried to end the roll with opposite pressure. That's unnecessary with the F-16XL's system, as Jim demonstrated. I tried it again, more smoothly this time.


We accelerated back to more than 400 knots and I tried more 360° rolls. Once I was accustomed to the correct control stick pressures, the roll rate was fast and the controls crisp. The same feelings were apparent at 500 knots – quick, sure response, with no feeling of carrying the heavy bomb load.


Next, Jim demonstrated the F110 engine's ability to accelerate from idle to max afterburner by slamming the throttle forward. Engine response was smooth with no coughing or stalling, thanks to General Electric's advanced electronic engine controls.


Then we descended to low level for penetration at high speed. Jim set up the aircraft at 600 knots indicated airspeed at 100 feet above ground level. The ride quality on a very hot day was smooth. The G-indicator on the head-up display (HUD) showed excursions of less than 0.2 above the below 1.0, but they were undetectable in the body. On similar flights with an F-4 as the chase aircraft, its G excursions were as high as 2.0, making for an uncomfortable ride and heavy concentration on flight controls.


In the loaded configuration, the F-16XL can penetrate at low level at airspeeds fifty-to-ninety knots faster than the basic F-6 when similarly configured. In fact, at every corner of the performance envelope, the aircraft has power in reserve, according to members of the Combined Test Force at Edwards.


Next, we conducted simulated weapons passes on a ground target, using the continuously computed impact point system (CCIP) displayed on the HUD. With this system, even this novice pilot, who has difficulty with a non-computing gun-sight, achieved on-target results. Attack maneuvers resulted in G forces ranging to +7.0.

With the heavy bomb load aboard, the F-16XL is cleared for maneuvers up to +7.2 Gs, compared with 5.58 Gs in the F-16A. This demonstrates how the designers were able to increase the aircraft weight while maintaining structural integrity and mission performance.


We returned to Edwards to land on Runway 22. Touchdown speed was 170 knots. When Jim deployed the drag chute, its effect was instantaneous, slowing us to less than eighty knots in less than 1,000 feet.


With the F-16XL, the US Air Force has the option to gain markedly improved range, payload, and survivability performance over current fighters. According to its designers, the F-16XL in production would have a unit flyaway cost of about fifteen to twenty percent more than the F-16C and D.

So what ever extra skin friction drag in tejas due to large wing area is completely cancelled out by the beneficial lift to drag ratio.

So it is time to wind up their favorite grip that compound arrow large are wing of tejas produces just drag and nothing else. People should stop another pet peeve that the crank at the tip of the wing in F-16 XL is not there in tejas and this is the cause of the all"problems"!!!!

Suffice to say compound delta wing form adopted on tejas is the best possible choice after through wind tunnel and CFD analysis.

So it is not the case of developers of tejas wanting to have highest capacity internal fuel fighter on a smallest airframe mistakenly designing a bigger wing to hold more fuel which led to excess drag .

While canards have their own advantages, they also perform worse in respect to wave and interference drag components.because another big right angled surface of resistance is offered to the oncoming air stream, which produces its own drag component.

ADA too experimented with the canrds and decided to drop it because they gave no specific extra performance for the weight and drag component they imposed.

Also the job of producing lift inducing vortex is done by lesser swept leading edge near the wing root , which is the same job done by canards. In addition the canards also act as another control surface.

But it has been compensated in tejas with far larger control surfaces attached to the back side of the wing.

They designed a fighter with wing area appropriate for the ASR under indian climatic conditions. Note tejas is supposed to fly from leh one of the highest airfields in the world where air density is lesser.

So without taking into account all these things , people should not jump to conclusions.


The link below lists various issues with canards.

http://www.desktop.aero/appliedaero/configuration/canardProCon.html

Fuel center of gravity lies farther behind aircraft c.g. than in conventional designs. This means that a large c.g. range is produced or that the fuel must be held elsewhere (e.g. strakes near the wing root.)

CLmax problems with flaps or margin on the entire wing: Flaps produce a larger pitching moment about the c.g. on a canard aircraft. This results in the need for both large canard aerodynamic incidence change and high maximum canard lift coefficient. Note that since the value of a S is usually larger for canard designs, Cm0 has a greater impact on L than it does on aft-swept designs.

Induced drag / CLmax incompatibility: Canard designs can achieve equal or better CLmax values than conventional designs, and similar values of span efficiency. However, the configurations with high CLmax values have terrible values of e and those with respectable e 's have low maximum lift coefficients.

Directional stability: The distance from the aircraft c.g. to the most aft part of the airplane is usually smaller on canard aircraft. This poses a problem for locating a vertical stabilizer and may result in very large vertical surfaces. (Note, however, that winglets may be used to advantage in this case.)

Wing twist distribution is strange and CL dependent: The wing additional load distribution is distorted by the canard wake.

Power effects on canard - deep stall: Accidents have been associated with tractor canard configurations for which the propeller slipstream has prevented canard stall before wing stall. The result is a possible deep-stall problem.

Finally, and perhaps most importantly, canard sizing is much more critical than aft tail sizing. By choosing a canard which is somewhat too big or too small the aircraft performance can be severely affected. It is easy to make a very bad canard design.

it is not as if canards have no disadvantages at all. Suffice is to say we should look at the holistic purpose behind the entire aerodynamic layout instead of getting fixated on one control surface to the exclusion of all other pitfalls.

 

[ersakthivel]

Aeronautical Engineering: canard's overall efficiency compared to conventional aircraft, tail dragger, tandem seating
-----------------------------------------------------------------------------------------------------------------------------------------------


Disadvantages

* The wing root operates in the downwash from the canard surface, which reduces its efficiency, although the effect of the downwash does not cause as large of a problem as the tailplane would experience in a conventional set-up.[citation needed]

* The wing tips operate in the upwash from the canard surface, which increases the angle of attack on the tips and promotes premature separation of the air flowing over the wing tip. This premature separation at one tip or the other would promote wing-drop at the approach to the stall, leading to a spin. This must be avoided by precautions in the design of the wing, and may require extra weight in the wing structure outboard of the wing root.[citation needed]

* Because the canard must be designed to stall before the main wing, the main wing never stalls and so never achieves its maximum lift coefficient. This may require a larger wing to provide extra wing area in order for the airplane to achieve the desired takeoff and landing distance performance.[citation needed]

* It is often difficult to apply flaps to the wing in a canard design. Deploying flaps causes a large nose-down pitching moment, but in a conventional aeroplane this effect is considerably reduced by the increased downwash on the tailplane which produces a restoring nose-up pitching moment. With a canard design, there is no tailplane to alleviate this effect. The Beechcraft Starship attempted to overcome this problem with a swing-wing canard surface which swept forwards to counteract the effect of deploying flaps, but usually, many canard designs have no flaps at all.[citation needed]

* In order to achieve longitudinal stability, most canard designs feature a small canard surface operating at a high lift coefficient (CL), while the main wing, although much larger, operates at a much smaller CL and never achieves its full lift potential. Because the maximum lift potential of the wing is typically unavailable, and flaps are absent or difficult to use, takeoff and landing distances and speeds are often higher than for similar conventional aircraft.[citation needed]

* In the case of an pusher propeller, the propeller operates in the wake of the canard, fuselage, wing and landing gear. Also, the propeller diameter is often smaller than optimum, because of ground clearance considerations at rotation. A smaller propeller operating in a large wake will result in reduced propulsive efficiency.[citation needed]


Although some of the advantages and disadvantages above apply to all situation a few of the disadvantages can be, and have been used in the design of high performance military aircraft were aerodynamic instability can allow for a large improvement in the maneuverability of the aircraft.[citation needed]

Though in the civil aviation industry the disadvantages are seen to far outweigh the advantages and few canard design civil aircraft have been successful though with exception of a range of light aircraft produced by Burt Rutan.[citation needed]


----------------------------------------------------------------------------------------------------------------------------------------------

 

[halloweene]

On some points you are right, on some other you forget the FBW systems that allowed to overcom most of these probs (see AV Week 1979 about mirage 4000)

 

[Kunal Biswas]

Interesting pics >>

KH2012 » LSP-02

KH2018 » LSP-08

 

[ersakthivel]

On some points you are right, on some other you forget the FBW systems that allowed to overcom most of these probs (see AV Week 1979 about mirage 4000)

Yeah, it was officially reported in government's tejas website that F-16 flies better with the Tejas fly by wire software.

And initial testing of tejas's fly by wire software happened at the facility where F-16 XL software was tested, according to reports I read somewhere.

All test pilots of tejas have praised it for its handling qualities, with the senior test pilot and group captain Suneeth Krishna saying that even the tejas mk-1 is a least equal to upgraded Mirage-2000 .

the above two pictures show the lesser swept wing leading edge angle of tejas which aids vortex generation in the same way as that of F-16 XL.

 

[ersakthivel]

these three snaps also show the lesser angle of the wing leading edge near wing root a unique vortex generating feature, same as that of F-16 XL wing root ,

 

[ersakthivel]

 

[ersakthivel]

On some points you are right, on some other you forget the FBW systems that allowed to overcom most of these probs (see AV Week 1979 about mirage 4000)

the compound delta's vortex generation observed , The F-16 XL too depends upon the same vortex generation effect as i explained above,

in Fig. 6 for angle of attack a = 13° and 18° . A fairly good comparison is observed. The vortical flow field captured in calculations is presented in Fig. 7. The particle traces illustrate the detailed structure of the rolled-up vortices.It is seen that the leading edge vortices are strengthenedas the flow develops progressively away from the leading-edge of the wing

 

[ersakthivel]

the following is the explanation given for the function of flaps in PAKFA,

In all the above pictures of tejas you can see the same flaps in operation.

vortex formation, has been extended and adapted for aircraft control, particularly at high angles of attack where conventional trailing edge surfaces lose effectiveness.

Down-deflected vortex flaps capture the vortex suction on their upper surfaces to generate an aerodynamic thrust force component that results in drag reduction.

Conversely, up-deflection of flaps magnifies the vortex to thereby increase wing lift accompanied by a drag force on the flaps.

The present invention combines the advantageous features of up and down deflected vortex flaps to induce thrust and drag forces in order to generate directional control moments.

Similarly, the differential operation of the flaps creates unequal lift increments on the wing panels to generate lateral moments.

The segmented, deferentially actuated flaps of the present invention thereby improve the ability and agility of high-swept thin wing aircraft during maneuvering at high angles of attack.

We can see segmented flaps acting in tejas in all the above pics with their individual up and down deflections.

And we can see the same vortex generation effect of those flaps on tejas in the picture above, albeit in low res. In addition to this the naval tejasmk-2 is slated to get the same kind of LEVCONS present in PAKFA.

If the air force wants it can ask ADA to add it to IAF tejas mk-2 as well. So if we look at the two differing angles of wing's leading edge, flaps operation and highly swept outer wing leading edge and movable LEVCONS,

there are lot of similarities in PAKFA wing design and tejas wing design in applying the same concepts in delta combination to reduce drag, increase lift and increase the better handling capability at high AOA.

So the job of canards is done by these flaps with out producing significant extra wave and interference drag is obvious from the above explanation.it answers most o the questions regarding why there are no canards in tejas,

So there is no use repeatedly disparaging a product without even trying to understand the basic principles behind its design and development.

Since there is no canard wings also reach their maximum lift co efficient in their peak AOA without any restriction leading to better handling at high AOAs,

since there is no need to design the canard to stall before main wing , there by preventing the wings to realize their max lift coefficient. So over all wing efficiency improves .So a crucial dis advantage of canrds listed below is also eliminated while retaining the same vortex generation effect of canards

Because the canard must be designed to stall before the main wing, the main wing never stalls and so never achieves its maximum lift coefficient.

This may require a larger wing to provide extra wing area in order for the airplane to achieve the desired takeoff and landing distance performance.[citation needed]

In the age of highly sensitive ASEA radar the elimination of extra radar reflections from the big canards jutting out at right angle in the front fuselage is another big plus, as well ,

also there are no restrictions in the Cg and CP movement since there are no canards

 

[abhi_the _gr8_maratha]

Canards are bad for stealth for a wide
number of reasons, including:
- Their effectiveness is much more
sensitive to their size and shape than
a horizontal tail, so edge alignment is
usually impossible (none of the
canards on the Typhoon, Rafale, nor
Gripen have leading or trailing edge
sweep aligned with the wing). This
contributes to RCS.
- They almost always require
anhedral or dihedral, so they are not
in a plane with the wing, which again
contributes to RCS.
- They require relatively "broad
shoulders" and bulky internal frame
structures in the front of the
airframe, which again contributes to
RCS. The empennage of aircraft with
horizontal tails can be contoured with
a lot more flexibility.
- The attachment points of the canard
to the fuselage are exposed to radar
from the front, unlike those of a
horizontal tail which is masked by the
wings and forward fuselage.
Bottom line, canards add complexity
and their aerodynamic requirements
make them incompatible with the
requirements of truly stealthy
designs.

 

[abhi_the _gr8_maratha]

As far as agility is concerned, US
designs have investigated canard
fighter designs extensively with four
different technology demonstrators,
but have found it to be an inferior
layout to the wing tail designs.
Basically, the wing tail designs can be
done with as as good or better
aerodynamic instability. They can be
done with equivalent or better
aerodynamic efficiency. LEXes can
provide better high AoA lift
enhancement than canards. And
wing-tail designs allow for LARGER
tails (vs canards) which improves low
speed handling and high altitude
control authority. The latest
preference is for the lobster tail
design (F-22 and F-35) which situates
the tails extremely aft of the airframe
for high control moments and the
concentration of the heavy engine(s)
near the Cg of the aircraft for minimal
polar moments. In all current US
wing-tail designs (since the F-16) the
tails provide lift not down force at a
level cruising attitude

 

[ersakthivel]

Since there is no canard ,wings also reach their maximum lift co efficient in their peak AOA without any restriction leading to better handling at high AOAs,

since there is no need to design the canard to stall before main wing ,

there by preventing the wings to realize their max lift coefficient.

So over all wing efficiency improves . because of the fact the main wing is never allowed to reach the angles close to stall angle its max lift coefficient is never reached,

Why?

In highly swept deltas the max lift comes into play only at high AOA , by preventing the wing to reach angles closer to the those AOAs canards stops the wing in realizing their full lift potential.

Because deltas are associated with high altitude, high alpha performance,


So a crucial dis advantage of canrds listed below is also eliminated while retaining the same vortex generation effect of canards

Because the canard must be designed to stall before the main wing, the main wing never stalls and so never achieves its maximum lift coefficient.

This may require a larger wing to provide extra wing area in order for the airplane to achieve the desired takeoff and landing distance performance.[citation needed]

 

[ersakthivel]

Canards are bad for stealth for a wide
number of reasons, including:
- Their effectiveness is much more
sensitive to their size and shape than
a horizontal tail, so edge alignment is
usually impossible (none of the
canards on the Typhoon, Rafale, nor
Gripen have leading or trailing edge
sweep aligned with the wing). This
contributes to RCS.
- They almost always require
anhedral or dihedral, so they are not
in a plane with the wing, which again
contributes to RCS.
- They require relatively "broad
shoulders" and bulky internal frame
structures in the front of the
airframe, which again contributes to
RCS. The empennage of aircraft with
horizontal tails can be contoured with
a lot more flexibility.
- The attachment points of the canard
to the fuselage are exposed to radar
from the front, unlike those of a
horizontal tail which is masked by the
wings and forward fuselage.
Bottom line, canards add complexity
and their aerodynamic requirements
make them incompatible with the
requirements of truly stealthy
designs.

it is important to note that the russians dropped canrrds in Su-35 and PAKFA as well, No american plane has had canards till date, The F-35 was studied with canard attachment first and the canards were dropped subsequently.

 

[laughingbuddha]

What is the MTOW of the Tejas in cold weather? Say from Leh? And what are the stores and fuel capacity in that config?

 

[ersakthivel]

What is the MTOW of the Tejas in cold weather? Say from Leh? And what are the stores and fuel capacity in that config?

That type of info is not available for any of the IAF fighters in service and the MMRCA contenders that were tested there due to the sensitivity involved.If you have please post

 

[ersakthivel]

Technically proficient value-add to 'Stop wasteful military deals' | Security Wise

Some info I once posted is the comments section of the Bharath Karnard Blog "securitywise" is there in the link above