The wing is the most important part of an aircraft since it produces the lift that allows a plane to fly. The wing is made up of two halves, left and right, when viewed from behind. These halves are connected to each other by means of the fuselage. A wing produces lift because of its special shape, a shape called an airfoil. If we were to cut through a wing and look at its cross-section, as illustrated below, we would see that a traditional airfoil has a rounded leading edge and a sharp trailing edge.
Aerodynamics Questions
How does a wing work?
What exactly do you mean by angle of attack? Since a wing stalls at high angles of attack, how is it possible for an airplane to perform a loop or similar maneuver without stalling?
I would like to know the formula to calculate the lift produced by an airplane's wing or helicopter's rotor (make the terms as easy to understand as possible).
I have a further question regarding the earlier answer on the lift formula. You use the same equation for an airplane and a helicopter, but what if the helicopter is in hover? The velocity in hover is zero, so the lift must also be zero according to this equation.
What is the meaning of the word streamlining?
How can you define aerodynamics and how it is different from streamlining? What is aerodynamics?
Does the shape of the nose on a rocket affect how high it goes?
What is a vortex generator?
What exactly is the purpose of the small wing?
What is the effect of a notch or sawtooth on the leading edge of a wing? What are the advantages of these devices for high-speed military and commercial aircraft?
What is a slat segment for?
I have noticed many times that the flaps at takeoff go down less than compared to landing even though surely enough the plane is heavier at takeoff. Why would this be so?
Can you explain what adverse aileron yaw is and what factors cause it?
During a space shuttle launch, they say that the shuttle has reached "max-q." What does that mean?
What does Max Q mean?
What is meant by the term finite aspect ratio (2D) or infinite aspect ratio (3D) on an airfoil's coefficient of lift? Is this difference related to the air coming around the wing at the tip?
Can a pilot hear anything inside the cockpit when breaking the sound barrier?
Is there such a thing as a channel plane?
What is "aircraft icing" and how does it affect an airplane?
Airfoil Questions
An airfoil is a cross-sectional shape used on wings and other streamlined surfaces. The questions answered below discuss the different types of airfoils, how they are designed and analyzed, and their various applications.
What is a supercritical airfoil?
How would you compute the lift of an experimental airfoil?
I need to know the lift and drag of a symmetric airfoil as a function of the angle of attack from 0 degrees to 90 degrees. I have seen tables for 0° < alpha < 15°, but I need it up to 90 degrees. Where can I find these tables?
Atmospheric Properties Questions
How does the air density affect an airplane?
What is the speed of sound?
What is the sound barrier?
How fast do you have to go to break the sound barrier?
How fast is the speed of sound at ground level?
Does sound travel faster through a solid, a liquid, or a gas?
What is the atmospheric pressure inside a typical commercial airliner?
Whenever I fly and the airplane is descending from altitude, my ears and forehead hurt so badly I feel like my head will explode. Why is that?
Flight Dynamics Questions
What is the meaning of the term "g force"?
How would I calculate the speed of an object upon contact with the Earth's surface, like if it fell from the top of a building?
Can you explain what adverse yaw is and how to solve it?
Do aircraft with piston engines or turboprops experience torque effects like helicopters do?
Aircraft Performance Questions
How fast does an average commercial airline plane go when it is taking off from the runway before takeoff?
Why is it that when an airplane is at a bank angle of 60 degrees, the loading on it has been doubled regardless of its speed?
Propulsion Questions
Why do many turbofan engines on airliners have a painted white spiral or bar on the spinner? What is that swirly thing painted on the fan of a jet engine?
Why do different aircraft have different numbers of propeller blades on their engines?
What is the difference between a jet engine and a rocket engine?
Can you explain how various jet engines work, including the turbojet, turbofan, turboprop, and turboshaft? In particular, what is the difference between a turbojet and a turbofan and which is more efficient?
What is the difference between two dimensional and axisymmetric nozzles?
How does a rocket fly?
Why is aluminum used in solid rocket propellants? What is the role of aluminum agglomeration in the combustion of propellants?
Can you explain overexpansion and underexpansion of the flow exhausted from a nozzle? What is the convention that dictates these definitions?
Helicopter Questions
Can you please explain how a helicopter moves forward? The blades of the helicopter rotate around the vertical axis, so it generates a vertical lift force. Then how do you get forward motion?
What does the helicopter term "engine overtorque" mean?
Spacecraft Questions
What do astronauts do on the space station?
How do space vehicles get to different planets? What kind of computers or equipment guide them there?
Vehicle Design Questions
Can you please explain the different parts of an aircraft, such as the wing, horizontal tail, vertical tail, and fuselage?
How is the center of gravity of an airplane calculated?
I was wondering is there a safer way to design an airplane that is somewhat more crash resistant?
Electronics Questions
What is the purpose of the lights on the outside of a plane?
What does radar cross section mean? What does it have to do with stealth?
Instrumentation Questions
How do you measure g's?
What is the difference between airspeed, true airspeed, equivalent airspeed, calibrated airspeed, indicated airspeed, and ground speed? Which of these speeds does a pilot see in the cockpit?
Shipping & Hydrodynamics Questions
Vehicles traveling through water encounter many of the same phenomena as those traveling through air. This section includes questions describing hydrodynamic principles related to the forces acting on objects in motion through water. Also included here are topics discussing the history of ships and other nautical subjects.
Aerospace History Questions
Accident Investigation Questions
What material is the black box made from and how does the box function? If the black box is indestructible, couldn't the plane be made out of it too?
Astronomy Questions
Astronomy is the science that studies the stars, planets, and other bodies of the heavens. This section is intended to address subjects ranging from the structure of various celestial bodies to the methods scientists use while observing the universe.
What are some good sources for astronomy pictures?
How did you choose to become an aerospace engineer?
What universities would you recommend to a student who wants to become an aerospace engineer?
Outside of formal engineering training, what kinds of courses do you think would be beneficial?
What does it take to become a professional engineer (PE) in the field of aerospace engineering?
How long did it take to find a job?
What is the salary like?
Is there a high demand for engineers in this field?
What do you enjoy most about aerospace engineering and engineering in general?
What hours do you work?
What are the pros and cons of your job?
What are the day-to-day responsibilities of an aerospace engineer?
What kinds of projects do you work on?
What drives you to work in the field you do?
I want to know the careers in aerospace/aeronautical industry?
What is a job description for an aerospace engineer?
What is the difference between an aerospace and aeronautical engineer?
I'm doing a report on aeronauntical and aerospace engineering and I need some information on what kind of education is needed to become an aeronautical engineer. Also, how can I get involved in the field of aeronautical engineering?
What are the basic courses to be taken in college for aerospace engineering? Which is the best university to transfer to?
I am looking into possibly becoming an aerospace engineer. I would like to know what universities offer the best programs and if there are any universities on an international scale that offer a good degree in Aerospace engineering.
What does an aerospace engineer do in a typical day on the job?
How much time is spent daily working on projects as an Aerospace Engineer? And just to be more specific, vehicle design?
Do you get short assignments, or assignments that drag on for long time? Does your job mainly deal with people, data, or things?
What are the responsiblities (ie: health and safety issues, legal, and ethical implications) of an aeronautical engineer?
What bonuses does this profession provide, such as medical and dental insurance, vacation, and holidays? What is your company's policy on being late and how to dress?
What advice will you give to a high school student who wants to be an engineer?
On average, how much does an aerospace engineer make in a year?
If I graduate college with a B.S. in Mechanical Engineering, can I attend graduate school in aeronautical engineering?
Can a mechanical engineering graduate work in the aircraft industry?
I'm very interested in becoming an aerospace engineer. However, I'm much more interested in spacecraft than airplanes. Is there such an option? Is it true that aerospace engineers get to do computer programming (which I enjoy) and even help design space missions?
What type of training does it take to become a metallurgist and how are they employed by the aerospace industry?
I want to be an astronaut and wondered what's the best way to get started in this field? How much college education does it require? If I had degrees and everything in order to be an aerospace engineer, would I be able to switch to an astronaut without tons of extra schooling?
Who do aerospace engineers work with?
I am currently a university student doing my preliminary year course, and I am stuck between Aerospace Vehicle Design and Flight Dynamics. I don't know which one to take. My career desire is to work in the air as a flight test engineer and on the ground with flight simulators and wind tunnels. Your advice? Also, do flight test engineers get to fly often, testing planes or something?
I'm interested in working for the armed forces. Do they need aeronautical engineers and what do they do?
I would like to know if one can get into aircraft accident investigations by studying aerospace engineering?
What exactly is the training necessary to enter the field of aerospace engineering? How would someone go about getting a license, an apprenticeship, or become an intern in this field?
I know this is a hard question because it varies. I was wondering how much someone in the aeronautical engineering field makes yearly?
How much money does a first-year aerospace engineer earn in this occupation?
Are there any aspects of aerospace engineering that are unexpected?
What are the advantages of being an aerospace engineer?
How many years of school did you attend and what degrees did you get? How heavy was the workload for your degree and what classes are the hardest?
How long would it take for a full time student to get his masters degree and Ph.D?
I am thinking about majoring in engineering. I like learning about space, but do aeronautical engineers have much to do with space besides designing spacecraft? Should I study engineering or another field?
I am an aeronautical engineering student and want to be a rocket scientist. How can I become one?
I'm confused about becoming an aerospace engineer or a commercial pilot. I want to know what do aerospace engineers do compared with pilots?
How much does an engineer have to work in a typical week? Is it hard to balance work and family?
Q. How safe is flying?
A. Flying on a modern jet aircraft such as any member of the Airbus family is amongst the safest and most reliable forms of travel. All Airbus aircraft meet the certification requirements of aviation authorities worldwide. Airbus works hand in hand with these authorities to ensure standards are maintained and enhanced.
Q. What are aircraft made of?
A. Variety of materials are used in the primary structure of our modern aircraft family.
Whilst aluminium is the traditional material for aircraft construction, and is still used extensively throughout an aircraft's structure, metal is being replaced by composites in many areas. Composite Structure typically represents around 30% of a modern aircraft structure.
What is Acrylic?
What is an acrylic sheet?
Have you ever looked at something made of plastic and wondered how it was made?
Are you aware that Jet-aircraft cabin windows are made from acrylic sheet?
Q) How does an engine work?
A.
Q) Why do Airplane Seats Have to be Upright for Takeoff and Landing?
Brussels, 7 April 2008
Commission Decisions on Mobile Communication
Services on Aircraft
What is meant by mobile communication services on aircraft (MCA)?
It means in-flight phone calls, e-mail type data communication and messages sent or
received by passengers using their own everyday mobile phones. It does not include
aircraft-specific phones, such as those integrated within the aircraft seat that are
made available by some airlines, nor does it cover operational communications
made by and to the aircraft's crew.
This service is currently limited to GSM1800 technology. The generic term mobile
communication services on aircraft (MCA) is preferred to the previously used "GSM
on-board" because other mobile technologies such as 3G could also be deployed in
the future, depending on market demand.
What are the technical requirements for airlines that wish to offer
mobile services to passengers during flights?
Airlines need to install MCA equipment, which is being produced by several mobile
equipment manufacturers. This consists of a "picocell" (a very small mobile base
station or mobile "mast") and a "Network Control Unit". The Network Control Unit
stops onboard phones trying to connect directly with land-based cellular networks,
which are not designed to deal with high-speed movement. Until now, the potential
disturbance to land-based mobile networks was one reason for prohibiting mobile
phone use in planes.
The other reason was the risk of high-power transmissions from mobile phones in
aircraft interfering with on-board navigation and avionics equipment. This risk,
already small, is made remote by the MCA service, which introduces a controlled
environment inside the cabin forcing all mobiles to connect only to the MCA system.
Mobile phones need to use much less power to connect to the base station that is
only a few metres away and on board the aircraft itself, rather than a base station
that is on the ground. Furthermore, each aircraft offering this service undergoes
stringent aeronautical testing before the MCA equipment is installed to ensure that
the aircraft is capable of supporting the MCA service without safety consequences.
The third element in the MCA system is a satellite link connecting the aircraft to
public phone networks on the ground. The same satellite link is already being used
for operational communications with the crew of the aircraft.
Why was it necessary for the European Commission to get involved in
MCA? Could these services not be dealt with by national authorities?
As planes in Europe typically cross several borders during flights, coordination at the
European level is the only way to enable one of the first truly pan-European
communication services. In order to ensure that new pan-European business
innovations like MCA have the opportunity to be assessed by the market, undue
regulatory obstacles and delays to commercial deployment need to be removed. A
particular difficulty within Europe has been the heavy national bureaucracy involved
for operators in having to deal with 27 or more national administrations at once, often
requiring different solutions to very similar problems.
In August 2007, the European Commission has already taken similar steps to
encourage the development of pan-European mobile satellite services (IP/07/1243).
So, concretely, what has the Commission done?
The starting point of the EU's involvement in MCA was the funding of the WIRELESS
CABIN research and development project between 2000 and 2002, which delivered
the technological development required to make in-flight telephony a realistic
proposition (see http://wirelesscabin.triagnosys.com).
Now that the technological solution has been developed, the Commission aims to
simplify and speed up market access for MCA operators by removing as much "red
tape" as possible. For this purpose, two measures have today been adopted by the
Commission:
- A Commission Recommendation for a harmonised approach on licensing
which will promote mutual recognition between national authorisations for
mobile communications services on board aircraft.
- A Commission Decision which sets out harmonised technical parameters of
onboard equipment for in-flight mobile phone use throughout the EU that
will allow Member States to recognise each other's licences for mobile
communications on board aircraft without risk to mobile networks on the ground.
The on-going certification of MCA systems with respect to air safety has also been
undertaken at EU level, via the European Aviation Safety Agency. The Commission
has furthermore encouraged national security authorities to share their know-how
and views on elements of MCA related to justice and home affairs.
Has the Commission consulted stakeholders while preparing these
measures?
In October 2007, regulatory aspects of MCA in the EU were discussed at a workshop
between all stakeholders in Brussels, including national and European regulators,
operators, airlines and consumer representatives.
Representatives of the Member States and national regulatory authorities were fully
involved in drafting final versions of the measures adopted today and gave very
broad support to the proposed approach.
What is the pricing policy applicable to MCA? Is it one fixed price or
does it depend on the country the aircraft is flying over?
During flight, each aircraft will effectively be a single "network in the sky" for MCA
customers, so the price will not be affected by the aircraft's location.
Who will determine the cost of calls made on board?
The service provider of the customer (i.e. the home cellular network operator that
furnishes the invoice) will set the retail price, taking into account all charges,
including agreements with the MCA provider, the air carriers, the satellite service
providers, and other mobile network operators.
How will the caller and receiver be charged for the calls?
They will be charged through their existing mobile account, as if they were placing a
call from abroad or using another mobile network while outside the reach of their
regular service provider.
What about customers using pre-paid cards?
It depends. People using their phones abroad are often not allowed to use their pre-
paid cards, unless they are roaming on networks that have a co-operation
agreement with operator they use at home. Otherwise they have a service
subscription which supports international roaming and they can use their cards
abroad. This will also be the case for MCA.
Does the EU's Roaming Regulation of June 2007 apply to calls made
to/from MCA?
The EU Roaming Regulation (IP/07/870), which will be reviewed before the end of
2008, has been adopted by the European Parliament and the Council of Ministers in
June 2007 primarily to deal with the issue of roaming on terrestrial networks. The
definitions of the Regulation therefore do not apply to MCA, even though it is in many
respects similar to a roamed service.
The EU Roaming Regulation expresses a very important single market principle that
the European Commission would like to see broadly applied and that can be defined
as follows: irrespective of location in the EU, one and the same communication
service should not be more expensive for the consumer than in his or her home
country unless there is a clear justification (such as additional cost for the operators).
This principle of course applies not only to the situation of using a mobile phone in
another country, but also to the use of a mobile phone in an airplane crossing
several EU Member States.
In a market economy, prices for communication services should first of all be
determined by market forces. This applies especially to MCA, which is still a
nascent service and still has to find to its business model(s). The Commission
therefore finds it preferable to give commercial forces the chance to work.
However, it is clear that the take-up of MCA would be best served if mobile network
operators pursue from the beginning a transparent pricing policy and avoid prices
which would be considered excessive by consumers or even represent shock bills.
The European Commission will keep a close eye on how this market develops.
Who will provide in-flight mobile phone services? How can I find out
more about it?
Although the market will fluctuate and evolve in the coming months and years,
depending on consumer take-up, two companies have been created specifically to
develop MCA services and are most advanced in this field. A number of airlines have
announced cooperation agreements with these operators.
Will all mobile devices be allowed on board?
The commercial systems currently envisaged are focussing on MCA services for
GSM phones operating in the 1800 MHz frequency bands, which over 90% of air
passengers are estimated to carry when travelling. The legal instruments adopted
today by the Commission address this technology at first, but will be extended to
other standards if there is demand for them.
A minimum altitude restriction of 3000 metres will apply to the use of
this service. Does this rule out the use of mobile phones on many
short-haul flights altogether?
Nearly all European commercial flights reach a non-critical phase of flight or “cruising
phase" over 3000 metres above ground. In other words, MCA will nearly always be
available, even if only for short periods of time on some flights – which is similar to
having to rush breakfast before you have to fold away your tray on the plane!
What is the Commission doing for passengers who do not want to be
disturbed by mobile phone use during flights?
The role of the Commission is to create the legal and technical conditions that help
new service providers and are required in a single market. As long as safety and
security are ensured, the way in which commercial services are provided is a
decision essentially for the private sector. The social aspects related to the use of
MCA technology therefore should be handled by the airlines as part of their usual
relationship with their customers, keeping in mind the special situation in aircraft
cabins where one passenger is normally located closely to another. Airlines may,
for example, remind or require passengers to turn mobile phones to silent mode; to
switch off the MCA service in particular circumstances, such as during turbulence
or at night; or designate certain areas of the aircraft cabin as 'quiet areas' where
mobile phone use is prohibited, as is the case on certain train carriages.
Will aircraft flying outside EU airspace have to switch off their mobile
phone service? Would this make calling on the plane unreliable?
If the aircraft is in international airspace (i.e. more than 12 nautical miles from any
country), the rules and regulations of the country where the airline is registered
apply: if the MCA operator has a national licence in that country, the aircraft can use
the service. If the aircraft is in airspace of a country that is not part of the EU, the
MCA operator normally will need an authorisation from that country to operate its
service, unless there is a special agreement between that country and the EU
allowing for mutual recognition.
It is likely that other countries (especially neighbouring countries) will align
themselves to the European approach, and the Commission believes Member
States will accept non-EU aircraft operating MCA systems, as long as their techni-
cal operating parameters are the same as those used in the measures agreed
today
In any case, airlines and MCA operators are unlikely to launch the service on given
routes without the guarantee of reasonably continuous operation for the passenger.
Why choose Steel Structures for your steel aviation hangars?
Will this type of construction work in my area?
What about concrete?
What tools are required to construct a steel building?
Do you have erection crews? We have access to independent crews that will travel and install your steel building. They will contract with the customer or owner of the building.
What does clear span mean? The building is designed and engineered with no interior columns for support.
What are the terms of agreement?
Can I Build Additional Improvements In A Hangar?
How is that Aircraft Hangar Regulated Anyway?
Where can I find more information on hangars?
For your project to be successful it must be com-
pelling to the key decision makers and stake-
holders. There are four key phases to create and
integrate a compelling business case for your
hangar project.
Phase One: Develop the business case
Phase Two: Check with stakeholders to ensure
the business case is compelling
Phase Three: Develop a basic presentation
Phase Four: Feed the business case into
your communications plan
Depending on the requirements of your project
and the demands of decision makers and key
stakeholders, you might not need to go through
all of this detail. However, it is beneficial to go
through these phases to ensure the project will be
successful even when faced with resistance.
Phase One:
Develop the business case
Review the questions listed in Phase One and
brainstorm other questions that will capture the
five aspects of a compelling business case. It is
important to document the business case, even
parts that seem obvious, because it gives everyone
the same point of reference for communication.
Parts of a Compelling Business Case
Questions to Ask to Develop Each Part of the Business Case
PART ONE:
Description of the project
What is the current situation?
Describe what will be targeted in the project.
What is currently going well that can be built on?
What has been done to confirm the need for new hangars?
Who authorized/initiated the project?
Description of the project importance
Why are the hangars needed?
What is the motivation of airport users for new hangars?
Do they perceive:
An opportunity – a situation leading to future success?
A need – a current shortage of hangar space?
A discomfort – an existing problem requiring a solution?
Pain – a severe problem requiring immediate response?
What situation demonstrated the current need?
Description of benefits of the new hangars
How will stakeholders benefit in the short run?
How will stakeholders benefit in the long run?
How will the airport, local community and owner benefit in the
short/long run?
What are the consequences of not doing the project?
What resources will be available to complete the project?
PhaseTwo:
Check with stakeholders to ensure
business case is compelling
In Phase Two, evaluate how compelling the
business case is to key stakeholders. Review
these questions, and check your business case
against them.
Parts of a Compelling Business Case
Questions to Ask to Develop Each Part of the Business Case
PART FOUR:
Description of the costs associated with
What will it cost in terms of money, time, and effort?
How will stakeholders be impacted by these costs?
What is the cost/benefit analysis (project proforma)?
PART FIVE:
Measures for success
How will success be measured?
What is the monitoring system?
What does success look like?
How will stakeholders recognize success?
The Stakeholder will ask:
The Stakeholder really wants to know:
PART ONE:
What does the project look like?
Is the project going to impact my business or daily work?
PART TWO:
Why is this project important?
What’s in it for me?
Who cares?
So what?
Is it going to negatively impact me?
PARTTHREE:
Is it good for business?
How will the project help my business?
How will the project make my job easier/harder?
How will the project make me look good/bad?
PART FOUR:
What will this cost me?
How will the project impact my budget, people, and time?
What do I have to give up if the project goes forward?
What additional workload will I have?
PART FIVE:
When will this be successful?
How do I know I’m done with this and can go back to my “real work?”
How will I know there is a positive impact on my business?
Develop a basic presentation
Once the business case has been drafted into
your plan and checked with a sample of stake-
holders, develop a presentation that can be used
for communication about the project.
Be sure that the communication plan you have
developed to gain the support of key stakeholders
includes a discussion of the business case. Also,
keep in mind that the business case will change
as the project progresses. Revisit the business
case frequently as conditions and situations
change, such as project cost increases.
Q) Why is this project important?
Next