Transport Aircraft for IAF

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shiv
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Re: Transport Aircraft for IAF

Postby shiv » 20 Dec 2010 17:52

Lalmohan wrote:shiv, to add to indranil's comments on roll and ailerons - in normal aircraft - wing dihedral (angle up from the fuselage when looking face on) is used to induce stability, i.e. return it to the neutral position following manoevres. Also, differential ailerons rarely operate symmetrically - the wing aerofoil section is not symmetric and the lift/drag curves are non-linear. the impact of up and down ailerons vary non-linearly

I recall reading that an anhedral configuration actually causes a roll tendency because the center of mass hangs below the wings like a pendulum that can rock from side to side. I guess a plane with an anhedral wing is less likely to "want" to return to stability?

I have observed this tendency to return to stability and level flight in model aircraft with dihedral wings. It's almost as though the presence of a dihedral wing automatically increases lift on the wing that goes down as it becomes more horizontal and the lift on the wing that goes up is reduced as it tends towards vertical, tending to "unroll" the aircraft. But with anhedral the wing that goes up becomes more horizontal causing it to lift further and accentuate the roll. Seems like that to me. Much of my mental image are etched in by several hundreds of hours of playing with flying models aeroplanes :oops:

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Re: Transport Aircraft for IAF

Postby Lalmohan » 20 Dec 2010 17:54

you are empirically correct!

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Re: Transport Aircraft for IAF

Postby Austin » 20 Dec 2010 20:22

UAC offers in India to produce the An-148 ( ato.ru )
Mon, 20/12/2010 - 17:11 | Maxim Pyadushkin

UAC intends to find in India an industrial partner for the joint production of AN-148, said Alexei Fyodorov, president of the corporation to open today in New Delhi, the Russian-Indian Forum on Trade and Investment, RIA Novosti reported.Source in the Russian aviation industry ATO.ru explained that as a possible partner considered Indian industrial giant HAL and Tata. "However, all agreed on joint production of AN-148 are still at a preliminary level and will be implemented in the event of a major order for the An-148 from the Indian airlines , "- said a source.

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Re: Transport Aircraft for IAF

Postby Lalmohan » 20 Dec 2010 21:34

interestingly - most large aircraft appear to have anhedral, but usually that is due to the weight of the wings, once they start generating lift (as it starts to roll down the runway) the wing bends upwards from the roots to form a dihedral geometry

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Re: Transport Aircraft for IAF

Postby Raman » 20 Dec 2010 23:10

Anhedral contributes to *unstability* while dihedral contributes to stability. The reason is not, as is commonly thought, due to pendulum effect. The reason that dihedral contributes to roll stability is the following sequence of actions:
- gust of wind pushes one wing slightly up
- bank causes side slip towards the lower wing
- due to slip, transverse airflow on low wing (with dihedral) increases effective angle of attack, increasing lift on low wing, correcting the bank
The opposite happens for anhedral.

The reason why large transports have anhedral is because a "high wing" contributes a few "degress of dihredral" worth of roll stability to the airplane. (This is also because of transverse airflow during side slip caused by gusts, but now it is because the fuselage causes a flow distortion that causes an upwash near the low wing, increasing its angle of attack. For similar reasons, low wings are less stable.) As such, some large high wing become "too stable" and do not want to turn easily. This is why they have anhedral installed - to make them more controllable.

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Re: Transport Aircraft for IAF

Postby Raman » 20 Dec 2010 23:14

It's almost as though the presence of a dihedral wing automatically increases lift on the wing that goes down as it becomes more horizontal and the lift on the wing that goes up is reduced as it tends towards vertical, tending to "unroll" the aircraft.


And therein lies the fallacy. The airflow around a wing doesn't care about the direction of gravity - the aerodynamic force is exactly the same regardless of absolute orientation in the world frame.

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Re: Transport Aircraft for IAF

Postby Indranil » 21 Dec 2010 06:33

Shivji, I don't think Ramanji ever tried to explain the ailerons or rudder controls (or their side effects ... He was just speaking of the effect of dihedrals/anhedrals. And he is dead on AFAIK.

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Re: Transport Aircraft for IAF

Postby shiv » 21 Dec 2010 07:06

indranilroy wrote:Shivji, I don't think Ramanji ever tried to explain the ailerons or rudder controls (or their side effects ... He was just speaking of the effect of dihedrals/anhedrals. And he is dead on AFAIK.

viewtopic.php?p=993355#p993355
Raman wrote:
Applying a left or right aileron induces a nose down attitude during the turn which is why one uses the rudder to maintain a level turn instead of loosing altitude on a turn using only ailerons.


This is incorrect --- the nose doesn't drop. Using ailerons causes one wing to develop more lift than the other, causing the bank. However, the lift differential also causes differential in induced drag --- the "high" wing develops more induced drag than the "low" wing. This causes the adverse yaw --- the nose rises a little and yaws towards the high wing, which is away from the direction of the turn, resulting in the aircraft skidding through the turn. The skid causes an unpleasant sensation and is inefficient because the side the fuselage is subjected to the airflow, causing a huge drag increment. As you pointed out, the rudder is applied to counteract this adverse yaw.

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Re: Transport Aircraft for IAF

Postby Indranil » 21 Dec 2010 08:23

shiv wrote:
Raman wrote:This is incorrect --- the nose doesn't drop. Using ailerons causes one wing to develop more lift than the other, causing the bank. However, the lift differential also causes differential in induced drag --- the "high" wing develops more induced drag than the "low" wing. This causes the adverse yaw --- the nose rises a little and yaws towards the high wing, which is away from the direction of the turn, resulting in the aircraft skidding through the turn. The skid causes an unpleasant sensation and is inefficient because the side the fuselage is subjected to the airflow, causing a huge drag increment. As you pointed out, the rudder is applied to counteract this adverse yaw.


He is right there too. Actually acrobatic displays by turboprop planes often use this skidding as a stunt. I think there is some gap between his explanation and your understanding. It is in 3D. He is not saying that the there is no induced roll when one uses the rudder. Now imagine this banked plane. Its longitudinal axis is (say) horizontal. Now in addition to this role, the plane experiences differential drag on the wings (higher on the outside wings). This pushes the outside wing backwards and hence the plane's longitudinal axis no longer stays horizontal, but at a positive AoA. So the plane is banked (caused by the differential lift) and at a positive AoA (caused by differential drag).

The nose drop that I was speaking off in my reply to Shalav was a simplification. That is the end result. There is a lot of aerodynamics and combinations (airspeed, CG, mass of the plane, shape of wing etc.) involved which I didn't want to go into then.

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Re: Transport Aircraft for IAF

Postby shiv » 21 Dec 2010 10:01

indranilroy wrote:The nose drop that I was speaking off in my reply to Shalav was a simplification. That is the end result. There is a lot of aerodynamics and combinations (airspeed, CG, mass of the plane, shape of wing etc.) involved which I didn't want to go into then.


The simple question is in a turn to the left (for example) does the pilot use his rudder at all? If he uses his rudder does he deflect the rudder to the left or right?

If the plane is turning left, it is already banked to the left. If the rudder is moved to the left the nose will go down (yaw to left) as the tail goes up. If the rudder is turned right, the nose will tend to point up as the plane is yawed to the right. Raman says the plane that is turning to the left will have a natural tendency to yaw to the right (towards the "high wing"because of differential lift). Does this require rudder correction? If so in which direction? Raman made no statement about what direction the rudder is deflected. Counter intuitively it appears that for a left turn the rudder must be deflected to the right to keep the nose up, or else the nose will tend to go down because of "lift" from the tailplane.

I understand that it is all in 3-D but I am doing my best to explain 3-D in words because what has been written does not fit in with what I have observed or what you are saying. Obviously "nose up and nose down" take on new meanings when a plane is banked say 45 degrees. Nose up and nose down while a plane is banking demand some yaw unlike level flight where nose up and nose down means pitch alone.

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Re: Transport Aircraft for IAF

Postby Austin » 21 Dec 2010 10:44

PD-14: Powering Up pg 82
Maxim Pyadushkin

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Re: Transport Aircraft for IAF

Postby Indranil » 21 Dec 2010 12:10

shiv wrote:The simple question is in a turn to the left (for example) does the pilot use his rudder at all? If he uses his rudder does he deflect the rudder to the left or right?

If the plane is turning left, it is already banked to the left. If the rudder is moved to the left the nose will go down (yaw to left) as the tail goes up. If the rudder is turned right, the nose will tend to point up as the plane is yawed to the right. Raman says the plane that is turning to the left will have a natural tendency to yaw to the right (towards the "high wing"because of differential lift). Does this require rudder correction? If so in which direction? Raman made no statement about what direction the rudder is deflected. Counter intuitively it appears that for a left turn the rudder must be deflected to the right to keep the nose up, or else the nose will tend to go down because of "lift" from the tailplane.

I understand that it is all in 3-D but I am doing my best to explain 3-D in words because what has been written does not fit in with what I have observed or what you are saying. Obviously "nose up and nose down" take on new meanings when a plane is banked say 45 degrees. Nose up and nose down while a plane is banking demand some yaw unlike level flight where nose up and nose down means pitch alone.


Shiv ji, I completely understand the difficulty of explaining 3D stuff in words. Hence I believe a lot of things are getting mixed up here.

It all started with Shalav saying that rudder has only yaw effect and no rolling effect - he was wrong there. Using the rudder alone for yaw will induce roll as others and I explained, which if uncorrected will lead to a zero lift condition, where the plane will nose dive.

Now lets move on to the ailerons.
Shalav also had got it wrong as to what the ailerons do to induce the bank, maintain the bank and then reverse the bank. In all modern planes, AFAIK ailerons are used to induce the bank as the moment is much higher and hence the response is much more niftier. However, Shalav went on to say that the plane has a tendency to pitch down (which is what Raman ji corrected). When a plane uses ailerons to bank, it has a tendency to turn towards the outward wing. which in this banked position actually leads to positive AoA (3D again). It is somewhat like the nose is not aligned in the direction of the planes turn. But then once the banking is achieved the ailerons are leveled this differential dissipates to a lower extent. However even with the ailerons leveled there is still some lift and drag differential. This is because the planes outer wings covers a circumference of a bigger radius. This makes the airspeed higher over the outward wing. This means that the outward wing (even with leveled ailerons) creates more lift and more induced drag. So the plane would continue to roll and skid (albeit by a much lesser extent than when the ailerons were deflected). This can be corrected in many ways. The designer has the all the control surfaces to play with to negate this differential and hence make the nose point in the direction of the turn. He can use the rudder, or the ailerons or a combination of both.

So to answer your question, what happens if I created a bank with ailerons (almost always) while turning left. Obviously the roll is counter clockwise. While the banking is being achieved, and once the required banking is achieved, reverse yaw will make the nose turn towards it right(clockwise). In a 45 degree bank, this reverse yaw would mean that the nose would get misaligned to the right and up. As a correction the rudder might be used (deflected left) to make the nose yaw to the left (an anti clockwise moment). Hence the nose will be pushed left and down. Generally the amount of deflection of the rudder is a function of the deflection of the ailerons which is very simple to understand.

Albeit there are other ways like using the ailerons themselves to negate the differential. So once the banking angle is reached, even when turning left, one would deflect the ailerons (ever so slightly) to create a clockwise roll moment to negate this unintended roll and yaw. Another method which is almost never used is providing more power to the outer engine. This is sluggish and maintenance prone. Probably Gilles can clarify if using differential power from engines is even in the manuals if the hydraulics fail.

Now for creating a pure yaw effect in a left turn, the rudder would be turned left. This would create a parasitic anticlockwise roll moment. The ailerons could be used to counter this roll moment. So left aileron would be down (ever so lightly) and the right aileron would be up (ever so lightly). Again the deflection of the ailerons would be a function of the deflection of the rudder.

Sorry for going OT. I hope the moderators don't mind a discussion on aerodynamics on this page.

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Re: Transport Aircraft for IAF

Postby Indranil » 21 Dec 2010 12:27

While on the subject ... enthusiasts might want to read about side slips (used for cross wind lading) and forward slips (used for high descent rates for landing).

I got interested in reading about it when the plane I was in did a crosswind landing (can't remember if it was Pune or Bangalore). The pilot made it so smooth, I couldn't help but go home and read about it.

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Re: Transport Aircraft for IAF

Postby shiv » 21 Dec 2010 14:22

indranilroy wrote:So to answer your question, what happens if I created a bank with ailerons (almost always) while turning left. Obviously the roll is counter clockwise. While the banking is being achieved, and once the required banking is achieved, reverse yaw will make the nose turn towards it right(clockwise). In a 45 degree bank, this reverse yaw would mean that the nose would get misaligned to the right and up. As a correction the rudder might be used (deflected left) to make the nose yaw to the left (an anti clockwise moment). Hence the nose will be pushed left and down. Generally the amount of deflection of the rudder is a function of the deflection of the ailerons which is very simple to understand.


Excellent - this is an exact answer to my question. Now to the second part of the question:

As an extension of the phenomena you have described imagine an aircraft flying in a continuous circular path with a 45 degree bank angle. As far as my knowledge goes this aircraft should gradually lose altitude and actully fly a corckscrew path down an hit the ground. Unless something is done to stop that.

If this corkscrew path down is to be avoided the vector that maintains altitude - i.e the force acting on the plane directly upwards and against gravity should be equal to the mass of the aircraft. Now clearly in a 45 degree bank the upward (anti-gravity) component of the lift is less than what it would be in level flight.

What would a pilot have to do to maintain altitude while flying in a circle?

It seems to me that he would have to point the nose up so that the engine thrust is now being used to provide some lift to compensate for the loss of lift away from ground in a 45 degree bank. In other words for a left turn, a nose that is misaligned to the right and up is an advantage to maintain altitude. But if the deflection caused by the explanation you have given so lucidly is insufficient, would it not be necessary to deflect the rudder in the exact opposite direction (i.e to the right in a left turn) to help keep the nose deflected to the right and up to maintain altitude?

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Re: Transport Aircraft for IAF

Postby Lalmohan » 21 Dec 2010 14:50

^^^nose up using opposite rudder and increased thrust to counteract the drag

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Re: Transport Aircraft for IAF

Postby Pratyush » 21 Dec 2010 16:57

Hmm.......

The thread is turning into a nice learning resource for the amatures.

Great.

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Re: Transport Aircraft for IAF

Postby Abhibhushan » 21 Dec 2010 18:23

Shiv said
point the nose up so that the engine thrust ...


Doctor Saab, it is simpler than that.
    Increase the angle of attack by pulling back thus increasing lift
    Increase power to prevent loss of speed because of higher drag at higher AoA
    Turn for as long as you want
    :)
The vertical component of lift now counteracts weight while the horizontal component provides the centripetal acceleration to let the aircraft turn and every one is happy.

Lalmohan: NO opposite rudder! Need for inside rudder has been explained earlier.

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Re: Transport Aircraft for IAF

Postby Raman » 21 Dec 2010 18:49

It seems to me that he would have to point the nose up so that the engine thrust is now being used to provide some lift to compensate for the loss of lift away from ground in a 45 degree bank. In other words for a left turn, a nose that is misaligned to the right and up is an advantage to maintain altitude. But if the deflection caused by the explanation you have given so lucidly is insufficient, would it not be necessary to deflect the rudder in the exact opposite direction (i.e to the right in a left turn) to help keep the nose deflected to the right and up to maintain altitude?

For regular flight, pointing the rudder to the right in a left turn will exacerbate the side slip effect, increasing drag greatly and causing the aircraft to lose even more altitude and/or speed. The yaw angle required for using engine thrust to support the aircraft is quite enormous. It is far better to use the most efficient mechanism on the aircraft to produce lift --- the wings. Thus, if you want to maintain constant circular flight to the left, in addition to banking to the left, you will have to (a) maintain left rudder as before to co-ordinate the turn, (b) pull up on the elevators to use the wings to produce more lift and (c) apply more thrust to counteract the drag and energy bleed caused by (b).

The dynamics you describe come in to play during knife-edge passes. In this case, the aircraft is usually banked to almost 90 degrees so there is little or no "vertical" component of lift at all. The rudder provides the trim to align the nose up and provide thrust component to keep the airplane up, and the elevators are held down to prevent the aircraft from turning. These are only possible on aerobatic aircraft with very large control surfaces and powerful engines. It is dramatic but very "inefficient."

EDIT: Ah, I see Abhibhushan got the answer in just before me.
Last edited by Raman on 21 Dec 2010 18:56, edited 1 time in total.

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Re: Transport Aircraft for IAF

Postby Singha » 21 Dec 2010 18:55

do pilots need to remember all this and put it into effect or the FCS takes care of it? I would hate to have to recall all this with a fighter on my tail.

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Re: Transport Aircraft for IAF

Postby Lalmohan » 21 Dec 2010 19:04

thanks for pointing out that i was inadvertently describing side-slipping!
probably explains much! :)

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Re: Transport Aircraft for IAF

Postby Raman » 21 Dec 2010 19:16

Singha wrote:do pilots need to remember all this and put it into effect or the FCS takes care of it? I would hate to have to recall all this with a fighter on my tail.

Using rudder in combination with ailerons for turning is more than second nature to pilots since it is drilled in from the very beginning, as is maintaining back pressure and/or managing the throttle. It is like explaining how to down shift in a turn, where explaining how to ease off the gas, perhaps hold the brake a bit, depress the clutch, change gears and let the clutch out all while turning the wheel sounds more complicated than it really is to a regular driver. :)

The FCS really helps as well. If there are non-linear effects because of effect of stores or aircraft peculiarities, the FCS can assist with corrections using differential ailerons and/or rudder, as well as damping out oscillations, etc.. FCS also really helps with taking care of issues with aeroelastic effects. I.e., at high speed, applying (say) down aileron on the wing warps the wing and causes it to twist down. This decreases the effective angle of attack and reduces lift. In some early aircraft, this resulted in aileron reversal at high speed --- you would move the joystick/yoke to the left and have the airplane bank right!! The FBW FCS lets you get away with these kinds of issues. You can use less rigid (and therefore lighter) structures than otherwise.

There have even been some mechanical solutions to correct adverse yaw: differential ailerons using mixers and Frise ailerons.

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Re: Transport Aircraft for IAF

Postby nachiket » 21 Dec 2010 19:26

Wonderful! This discussion should be archived even if OT.

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Re: Transport Aircraft for IAF

Postby ashokpachori » 21 Dec 2010 20:10

Image

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Re: Transport Aircraft for IAF

Postby Indranil » 22 Dec 2010 00:41

^^^ Ashok, I am sorry that I am making yet another example of your post.

Could you please explain the reason of the above post. That diagram explains how the rudder causes yaw, ailerons cause roll and elevator give pitch control. Do you think we were discussing any of that or that anybody here doesn't know something that elementary?

I don't want to do any policing. The moderators are very much upto their tasks. But I implore posters to make pertinent posts. Look at Raman ji, Kartik and indeed many others. They make one post in 2-3 days and posters wait for their posts to learn more. There was a time a couple of years back where posters were very strict about the quality of posts. During my years of lurking here, I used to be scared of posting.

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Re: Transport Aircraft for IAF

Postby ashokpachori » 22 Dec 2010 01:46

indranilroy wrote:^^^ Ashok, I am sorry that I am making yet another example of your post.

Could you please explain the reason of the above post.



There are people in the following form just few posts away:

The thread is turning into a nice learning resource for the amatures.

And that was intended for them, and some probable laymen lurkers who might be intersted in such animated beginer stuff. The post was not intended for you, so dont loose your cool. I have migrated from other forum so I am not fresh off the boat, hence take it easy.

Reason explained!

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Re: Transport Aircraft for IAF

Postby Indranil » 22 Dec 2010 07:37

I am not loosing my cool :). Sorry if I am coming across like that. And as I said before it is nothing personal against you. It applies to all posts and posters. Please please mark my posts out when you feel that it doesn't add anything new. It will make me a better poster.

For newbie things like the graphics you put up, I think it is better if you use the newbie thread. Just put a link to this discussion and post the graphics. Newbies will appreciate it. Arrogant posters like me who don't like dilution of thread discussions will also appreciate it.

These are JMT and my personal experience. Please do as you think apt. But personally I miss the glory days of BRF when posts used to be laden with information. Unwanted posts would be blown to smithereens. For example in this case, if posters didn't know about rudder, ailerons and elevator they would rather stay out! Nowadays I literally skim over so many posts. Everybody seems to be posting everywhere. Sorry for the rant.

I request the moderators to delete our last few posts for being OT.

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Re: Transport Aircraft for IAF

Postby Austin » 24 Dec 2010 11:35

India's regional aircraft could be a jet
By Greg Waldron

India's first indigenous regional aircraft, the RTA-70, could be powered by turbofan engines, with the government viewing it as a stepping stone to larger aircraft.

Although the RTA-70 (regional transport aircraft-70) was originally envisaged as a 70- to 90-seat turboprop, the Indian government asked National Aerospace Laboratories to investigate the use of turbofans. NAL is studying the two options, and will report to the government in April 2011, after which a decision will be made.

"The government asked us to look at the turbofan option, and after we conduct a feasibility study, we will decide," says NAL director AR Upadhya. "Previously, we were focusing only on a high-wing turboprop design. If all goes well, by the end of 2011 we will have full go-ahead to create the aircraft."

NAL has been in talks with jet engine producers, including General Electric, Pratt & Whitney, Rolls-Royce and Snecma. It says all have shown interest in the project.

"Initially, we were looking only at the turboprop option because of the high price of fuel," says Upadhya. "Lifecycle costs were our key concern. The government then asked us to look at the turbofan option, because they see it as a stepping stone to the high end."

NAL foresees demand for regional aircraft in India reaching 250 by 2025. This is driven by India's increasingly wealthy middle class, and its demand for flights on low-cost carriers. In addition, industries are moving into India's smaller cities, increasing the viability of regional flights to those destinations.

NAL also sees possible demand for 150 military variants to replace the Indian air force's Antonov An-32 fleet.

Irrespective of the RTA-70's powerplant, it is likely to come in two variants - a shorter one with 70-90 seats and a longer one with 80-100 seats. Its range will be 1,350nm (2,500km), suitable for most long sectors in India. Avionics are likely to be produced locally, and include an indigenous fly-by-wire control system to save weight.

Upadhya estimates the aircraft could be in service as soon as 2017, and NAL is open to international and local partners. The aircraft would be produced by government-owned Hindustan Aeronautics.

If India were to produce the RTA-70 as a jet, it would find itself in the increasingly crowded field of 50- to 100-seat regional jets. Competitors would include the Bombardier CSeries, Comac ARJ21 Embraer's E-Jets and the Sukhoi Superjet.

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Re: Transport Aircraft for IAF

Postby Victor » 24 Dec 2010 13:20

People interested in the nitty gritty of flight dynamics and in getting a realistic feel for "flying" without joining a flight school will enjoy the Microsoft Flight Simulator series of programs. They are used in training real pilots and the flight manuals are as thorough as real ground school texts. Just as with learning to ride a bike, it is more productive to actually do it first and then be fascinated and amazed by the complex variables and instincts involved. That is why the first thing they normally do in flight school is take you up and give you the stick for a few moments. At least with flight sims, you won't get sick.

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Re: Transport Aircraft for IAF

Postby Philip » 24 Dec 2010 13:21

I am not against indigenisation and Indian designs,but when the field is so crowded with 50-100 seaters from proven manufacturers like Bombardier,Embraer,Sukhoi (whose Superjet will fly with western engines-mock-up was displayed at an Aero-India),etc.,what chance will the NAL have in perfecting and producing an aircraft within 6 years,that too at what cost?! It would've been far better to have examined the players' wares and co-produced a similar aircraft with inputs/ requirements for Indian conditions.This would be a faster and cheaper way of doing so.If China with its huge captive market can get Airbus to set up an A-320 factory in China to meet its needs,it shows a maturity of thought in getting a proven aircraft production line to meet its immediate and future needs,rather than taking the risk all on itself.Even if we do produce a good aircraft,the competition would be huge and exports would be v. difficult.Since the MTA is also under devlopment,why can't a version of the MTA be dsigned for civilian use too? This would then bring down costs sufficiently to tempt airline operators.

We know what happened to the Saras prototype.We have yet to perfect an indigenous aero-engine ourselves and get in into production and Saras was overweight.We do not produce enough composite materials within the country and have to import our requirements.What would be a better option is that with HAL's long experience in producing the DO-228s,also the large number of ATRs in service,to scale up a turbo-prop to a 100 seater,which would be economical to operate,plus would have a good export potential and even have variants for maritime patrol/ASW,EW,etc.There is a good demand for "low and slow" MRP aircraft globally and the ATR has a virtual monopoly here with the "42/72" versions.This could even be looked at as an AN-32 future replacement by 2020 when the upgraded AN-32s wil be long in the tooth.

The way to go is to design and develop at home (even with foreign assistance if need be) the basic trainers,IJTs,AJTs,and similarly a range of transport/utility aircraft from Do-228 upwards.These are required in large numbers and could be manufactured very cost-effectively.Once we've mastered all aspects of these types,including engine designs,we should move onto totally indigenous designs for larger types.

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Re: Transport Aircraft for IAF

Postby KiranM » 25 Dec 2010 17:36

Austin wrote:India's regional aircraft could be a jet
By Greg Waldron


Considering that there is no pressing commercial or military need for an RTA; GOI should provide resources to GTRE to set up another team to build a turbo-fan for RTA. Rather than import and strap one on.

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Re: Transport Aircraft for IAF

Postby vic » 25 Dec 2010 18:11

RTA seems to be growing in size. It was supposed to be 50 seater, then 70 seater, then 3 versions including 90 seater and Now it is going upto 100 seater turboprop. I think that NAL should be mandated with 30 seater stretched Saras and Turboprop RTA both in Civilan and Military versions 50-70-90-110 seaters. The turbofan passenger version should be given to HAL and capacity should be increased to 240-220-180 seater for mid distance range of 2000, 4000, 8000 km i.e. slightly bigger than Airbus 320, 737 and MS 21 series

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Re: Transport Aircraft for IAF

Postby Aditya G » 25 Dec 2010 19:18

Austin wrote:India's regional aircraft could be a jet
By Greg Waldron

...NAL also sees possible demand for 150 military variants to replace the Indian air force's Antonov An-32 fleet....


Such claims of "possible demand" from IAF are more reason for heartburn. Will the IAF ever replace a rear ramp cargo hauler with a civvie passenger jet? In any case it is the HAL-UAC jv that will ultimately produce the An-32 replacement.

IAF committed to replacing th Avros with the Saras - and instead lost 2 fine test pilots to the program. NAL should rather invest itself to the AMCA and UAV programs which are high priority.

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Re: Transport Aircraft for IAF

Postby Indranil » 26 Dec 2010 01:44

^^^ This is not right. Hack and Saras are nowhere in same payload category. So Saras's where never meant to replace Hacks. They were supposed to replace the Dorniers. Anyways, I share your hurt-burn on the Saras saga. There seems to be absolutely no sense of urgency. I have a lurking fear that Saras will go Hansa's way.

I feel the turboprop variant of the RTA will be an excellent replacement for the AN-32. It is high winged, supposed to have short runway requirements. Why can't it do the job?

Just fix the target. It seems to be moving all the time!

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Re: Transport Aircraft for IAF

Postby Indranil » 26 Dec 2010 01:44

Having said that even I feel that something is not right at NAL. I believe there is no systematic expectation-delivery mechanism. NAL is a research lab. Who is the user for these research? Research has to be directed. I think there should be a mechanism through which an end user should drive a production unit (like HAL) and the production unit should channelize research. We came up with Hansa-3. Where is it being used barring a few sports clubs at Safdarjung airport? And we are ending up importing basic trainers!!!

Similarly, I had read about the engines for Hansa-4 being decided in 2002. I don't think that there is even a prototype in 2010!

Since we are on the subject of heartburn, I have serious heartburn on the HTT-35. Now come on HAL! Going by your capabilities I am very sure you could have built a prototype of the HTT-35 in 3 years! You, our brethren, lost the money!

Our LIFT is BAE Hawk, a sub-sonic plane which supposedly cannot maintain full control authority at high AoA (I am not surprised). And now that we have them here, I don't think that the IAF will have another training stage after the Hawks. Hence, I don't know if we will ever see a IJT upgraded CAT or a Tejas based LIFT in-service anytime till these Hawks are retired!

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Re: Transport Aircraft for IAF

Postby Aditya G » 26 Dec 2010 15:38

indranilroy wrote:^^^ This is not right. Hack and Saras are nowhere in same payload category. So Saras's where never meant to replace Hacks. They were supposed to replace the Dorniers.


Hi Indranil,

Saras will replace the Hs-748s in communication and training roles - I think there was an order of 14 aircraft placed. There are no plans to replace the Do-228 - whose production is still on.

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Re: Transport Aircraft for IAF

Postby Indranil » 26 Dec 2010 23:56

From whatever, I have read I have come across the Saras as a Dornier replacement. I would be very glad to know better.

link
link

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Re: Transport Aircraft for IAF

Postby srai » 27 Dec 2010 08:44

Aditya G wrote:
indranilroy wrote:^^^ This is not right. Hack and Saras are nowhere in same payload category. So Saras's where never meant to replace Hacks. They were supposed to replace the Dorniers.


Hi Indranil,

Saras will replace the Hs-748s in communication and training roles - I think there was an order of 14 aircraft placed. There are no plans to replace the Do-228 - whose production is still on.

indranilroy wrote:From whatever, I have read I have come across the Saras as a Dornier replacement. I would be very glad to know better.

link
link


IAF currently has the following (BR IAF ORBAT):
  • 119 x An-32
  • 68 x HS-748
  • 24 x Do-228

Based on the current orders/plans, IAF will be replacing these three types with a mix of new types:
  • 45 x MTA (+40 options)
  • 12 x C-27s (+12 options)
  • 15 x Saras (+20 options)
  • ?? x RTA-50/70/90

So this does not seem like a one type-to-one type replacement.

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Re: Transport Aircraft for IAF

Postby neerajb » 27 Dec 2010 09:31

indranilroy wrote:^^^ This is not right. Hack and Saras are nowhere in same payload category. So Saras's where never meant to replace Hacks.


I believe you meant Avro HS 748, HACK is the name of the testbed that crashed and not all Avros are hack. Just nitpicking. :)

Cheers....

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Re: Transport Aircraft for IAF

Postby Indranil » 27 Dec 2010 09:38

Thanks for the correction :)

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Re: Transport Aircraft for IAF

Postby Dileep » 27 Dec 2010 10:54

Had the opportunity to talk to a paanwala somewhere in the pvt sector, who sold paan to the people working late midnight, trying to grab some slices of RTA pie. Heard the term NCAD (National Civil Aircraft Development) for the first time. Did a search here at BRF, got no hits. Checked googlammaan and got the site: http://www.nal.res.in/ncad/index.htm

I found that the same LCA habit of shooting the moon does persist. The apparent target is to 'out-spec the 787'.


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