Surveillance Systems : :)

avionics ->>)

http://aeroden.files.wordpress.com/2011/12/survelience-system.ppt

Raymer-aircraft design-a conceptual approach

link :

http://aeroden.files.wordpress.com/2010/12/84632___raymer_-_aircraft_design_-_a_conceptual_approach.pdf



all the best for SADD .....:(

VSD - grehem kelly .... :)

http://aeroden.files.wordpress.com/2011/08/schaum__039_s_outline_of_mechanical_vibrations.pdf


click on above link for book - good for basics :

VSD - SS RAO .... :)

vibrations ... subjects creating vibrations in and out ...

here is text book for VSD ..

 link :http://www.ziddu.com/download/17723355/51092484-Mechanical-Vibrations-by-s-s-RAo-ebook2.pdf.html

good luck ... :) ..

computational-fluid-dynamics-vol-ii-hoffmann

exams .. exams ... exams ... starting nite outs ???


start following blog for regular updates of important materials again ... here is book for uncovered topics from CFD anderson .. specially grid generation .,

 http://www.ziddu.com/download/17723271/computational-fluid-dynamics-vol-ii-hoffmann.pdf.html


good luck aerozzz ...:)

How Airplanes Fly................

PLACEMENT MATERIAL --- very important

Good morning AErozzz .... this is link for placement material, it is really useful for placement patterns of various MNCs , and tips for resume preparation , interview guidance .......have glance

download link :

http://www.ziddu.com/download/16242191/placement_material.doc.html






All the best for final battle ( interviews) .....

Thank you . ;>))

"Adverse yaw" and how to solve it ?????????

To understand what adverse yaw is, we need to first explain the axes of motion for an airplane. An aircraft in flight can rotate around three different axes, as illustrated below.


Aircraft axes of motionFirst, the aircraft nose can rotate up and down about the y-axis, a motion known as pitch. Pitch control is typically accomplished using an elevator on the horizontal tail. Second, the wingtips can rotate up and down about the x-axis, a motion known as roll. Roll control is usually provided using ailerons located at each wingtip. Finally, the nose can rotate left and right about the z-axis, a motion known as yaw. Yaw control is most often accomplished using a rudder located on the vertical tail.


Aircraft control surfacesHowever, the effect of one control surface is not always limited to just pitch, roll, or yaw alone. When the deflection of one control surface affects more than one of these orientations, we say that the orientations are coupled. The most important of these coupled interactions is adverse yaw. To better understand the concept, let's study a picture of what happens when the pilot deflects the ailerons to roll the aircraft.


Effects caused by aileron deflectionAs you can see, the aircraft rolls because one aileron is deflected downward while the other is deflected upward. Lift increases on the wing with the downward-deflected aileron because the deflection effectively increases the camber of that portion of the wing. Conversely, lift decreases on the wing with the upward-deflected aileron since the camber is decreased. The result of this difference in lift is that the wing with more lift rolls upward to create the desired rolling motion.
Unfortunately, drag is also affected by this aileron deflection. More specifically, two types of drag, called induced drag and profile drag, are increased when ailerons are deployed. Induced drag is a form of drag that is induced by any surface that generates lift. The more lift a surface produces the more induced drag it will cause (for a given wingspan and wing area). Thus, the wing on which the aileron is deflected downward to generate more lift also experiences more induced drag than the other wing. Profile drag includes all other forms of drag generated by the wing, primarliy skin friction and pressure drag. This profile drag increases on both wings when the ailerons are deflected, but the increase is equal when the ailerons are deflected by the same amount. However, the induced drag on each side is not equal, and a larger total drag force exists on the wing with the down aileron. This difference in drag creates a yawing motion in the opposite direction of the roll. Since the yaw motion partially counteracts the desired roll motion, we call this effect adverse yaw.
We can correct for this effect in several ways, the most important methods being:

1. Frise ailerons: The concept behind this particular kind of aileron is to minimize the profile drag on the wing with the down aileron while increasing the profile drag on the wing with the up aileron. This difference in profile drag counteracts the effect of induced drag thereby creating a yawing motion that at least partially cancels the adverse yaw effect.
   
   Frise aileronsFrise ailerons accomplish this differential profile drag by maintaining a smooth countour between the upper surfaces of the wing and aileron, causing very little drag, while the bottom surface of the aileron juts downward to create a large increase in profile drag. Although this approach is simple and does provide some relief, the performance of Frise ailerons is very dependent on operating conditions. For this reason, such ailerons are often only partially effective at overcoming adverse yaw.
2. Differential ailerons: Another approach to solving adverse yaw is to deflect the ailerons by differing amounts. The deflection of the down aileron is typically much less than the up aileron so that the additional profile drag is very small compared to that on the up aileron.
   
   Differential aileronsAs in the case of Frise aileron, this differential profile drag produces a yawing motion that at least partially offsets the adverse yaw, but the effect is limited.
3. Spoilers: Spoilers are long narrow flat plates typically fitted along the upper surface of both wings. In normal flight, spoilers lie flat and generate no effect on the aerodynamic performance of the wing. However, the spoilers can be raised upward into the air flow to generate large turbulence that reduces the lift and increases the drag on a wing.
   
   SpoilerWhen used in coordination with ailerons, a spoiler can be used to reduce the lift and increase the profile drag on the wing with the up aileron. As a result, the wing with the down aileron experiences a large increase in lift and a small increase in drag while the wing with the up aileron experiences a large decrease in lift and a large increase in drag. These effects combine to create the desired roll motion and a complimenting yaw motion that is called proverse yaw.
4. Cross-coupled controls: One of the most effective solutions to adverse yaw is to couple the ailerons and rudder so that both surfaces deflect simulataneoulsy. As the ailerons create a yaw motion in one direction, the rudder automatically deflects to create a yaw motion in the opposite direction. The two effects counteract each other eliminating the undesired yaw. This form of cross-coupling was often built into the cable-and-pulley control systems of older aircraft. The problem was recognized even as early as the Wright brothers who incorporated such controls into the Wright Flyer. In addition, most major aircraft today utilize some sort of computerized fly-by-wire control system, and it is rather trivial to program cross-coupled control measures into the automated systems.

How do helicopters without tail rotors, like the V-22 and Ka-50, counter the torque effect? How are they able to spin on the spot?

Both of the aircrafts  mentioned are equipped with two rotors. The V-22 Osprey has one rotor mounted on each wing tip and the Ka-50 Hokum has two mounted on the same shaft. In both cases, the two rotors rotate in opposite directions. As we know about torque effect, counter-rotating propellers and rotors generate opposing torques that cancel each other out.

                                                     Ka-50 with coaxial rotors
The second part of question has to do with rotor dynamics. You may not realize it, but helicopter rotors are designed to move in more ways than just rotation about the central hub. The individual blades are also able to rotate or pitch up and down so they meet the air at higher or lower angles of attack. This change in blade pitch is accomplished in two ways. The first, calledcollective, allows the pilot to change the pitch of all blades simultaneously. At takeoff, for example, the pitch of all blades is increased until the rotor produces enough lift to exceed the weight of the helicopter. Thus, collective is used to change a helicopter's altitude
A second method of changing the rotor blade pitch is called cyclic. This control allows the pilot to change each blade's pitch angle independently. By doing so, a traditional helicopter can be made to roll or to move in a particular direction. The cyclic lever works much like the control stick or yolk on an airplane. For example, pushing the lever forward causes the helicopter to move forward. This motion occurs because the control stick deflection forces the forward-moving (advancing) blades to pitch to a lower angle of attack and the backward-moving (retreating) blades to pitch to a higher angle of attack. As a result, the entire rotor is tilted down towards the heliopter nose. This causes the lift vector to tilt forward creating a thrust component that moves the helicopter forward. Similarly, pulling the stick back moves the helicopter backward, moving it left moves the helicopter to the left, and so on.



                                              V-22 with twin non-coaxial rotors
However,  question relates to yaw control, or the ability of a helicopter to turn left or right. Most helicopters accomplish yaw control using the small tail rotor. By changing the pitch of the tail rotor's blades, this rotor will produce a side force that turns the helicopter nose left or right. Since neither the V-22 nor the Ka-50 have a tail rotor, how are they able to yaw? They do so using the cyclic. If a helicopter has two rotors, it can tilt one as if to move to the left and another as if to move to the right, but the combined effect causes the helicopter to spin while hovering over the same spot. This scenario explains how both the V-22 and Ka-50 are able to yaw while in hover. Tandem rotor helicopters, like the CH-47 Chinook, and intermeshing rotor helicopters, like the Kaman K-MAX, also rely on differential rotor cyclic to provide yaw control. 

Thread For Aeronautical Students [Text Books ] - Jntu World

http://forum.jntuworld.com/showthread.php?2938-Thread-For-Aeronautical-Students-Text-Book


many useful books in above thread ... hava a glance ....;>))


team AeroZzZz......

COMPUTATIONAL AERODYNAMICS - ANDERSON

HI all .....

new beginning - new possibilities ..... yes ..... i m talking about our college ......

its going great ... and let us try to maximize our effort in last academic year @ COLLEGE....

link for text book ( CFD - ANDERSON ) :


http://www.ziddu.com/download/15866976/cfd.pdf.html




ALL THE BEST 

dynamics of flight by etikins ..;>)

dynamics of flight by etikins  ..... covers basics ..... flight mechanics .....

lots of bla bla to study .....

download link :

http://www.ziddu.com/download/14517571/dynamics_of_flight_by_etkins.pdf.html.

;>)))

happy preparation ........

Analysis and Design of Flight Vehicles Structures, Bruhn ....... **important **

xams xams ..... sounds hard to listen ... still , ...

need to study ..;>)

http://www.ziddu.com/download/14517378/Analysis_and_Design_of_Flight_Vehicles_Structures_Bruhn.pdf.html

very good buk ..;>)

cheers and happy preparation all ......;>)

by -- vissu30,
         team aerozz ....

attention ... change in lab exam dates , and procedure

attention aerozz ...
lab exam postponed to 08-04-2011 ......
exam begins at  9 am , and no need of c program , excel sheet pakka ....
exam pattern :
FVD - excel sheet , written test , viva voce
AVS - written test , viva voce .......

good luck all ..... keep chimping books ....

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

important questions for AP2 :: 4-8 units

                                         AEROSPACEPROPULSION -II

1)  . Identify the components of a solid propellant rocket motors with a sketch. Explain

briey the components.

2) What are the characteristics of liquid propellants and the types of liquid propellants.

Give the examples of each.

3)  write short notes on :

    (a) Photon propulsion

(b) Free radical propulsion

(c) Nuclear fusion

(d) Problems associated with plasma jet propulsion.

4)   Discuss the advantages and disadvantages of scramjet.

5) Compare the solid propulsion systems with liquid propulsion systems and mention

their comparative advantages and usage.

6)  

(a) Explain the following with respect to a rocket motor:

      i. Impulse to weight ratio

      ii. Total impulse.

 (b) Di_erentiate between a rocket and a missile..

-------------------------------------------------------------------------------------------------------------all the best aerozzz...