Tech questions that need answering
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Tech questions that need answering
1. Whilst maintaining a constant attitude,whatis the effect of flap's and slat's on the AOA.?
2. Besides using the scale , where can you measure distance on a Jep chart.?
3. Clearway will increase/decrease MTOW, and increase/decrease V1?
4. Stopway increases ASDA/TORA/TODA ?
5. What is service ceiling/absolute ceiling
6. How does crosswind effect the critical engine (is there such a thing on a jet/)
Thanks a million guy's & girls
2. Besides using the scale , where can you measure distance on a Jep chart.?
3. Clearway will increase/decrease MTOW, and increase/decrease V1?
4. Stopway increases ASDA/TORA/TODA ?
5. What is service ceiling/absolute ceiling
6. How does crosswind effect the critical engine (is there such a thing on a jet/)
Thanks a million guy's & girls
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LYKA,
1, AOA is the angle the aerofoil makes with the datum , the horizon. FPA (Flight path angle)is zero in level flight.So...when you increase the camber of the aerofoil ie. by extending flaps and slats the AOA increases and the lift increases thereby creating a buoyancy effect which has to be counteracted by applying down elevator to maintain level flight and a constant FPA. In answer to your question..The AOA increases.
2, As an approximation, use your forefinger to measure distance between 2 waypoints not to far apart on the chart and you will know how many miles your finger measures on a Jepp chart.
3,This is a tricky one.......here is what i feel. A clearway at the end of the RWY will increase your RTOW in the same way as if there was an obstacle close to the RWY one would have to reduce RTOW./ A clearway will have no effect on V1. I will however be open to more logical views.
4, A stopway will increase ASDA 'cos you have more rwy to accelerate and then stop. It will have no effect on TORA.It will increase TODA.
5,As height increases more power is needed to maintain level flight and less power is available. An airplane is said to have reached it's absolute ceiling when full climb thrust is needed to maintain level flight.Service ceiling is defined as the altitude at which the ROC has reduced to a 100fpm.
6, There is no such thing as a critical engine on a jet.
1, AOA is the angle the aerofoil makes with the datum , the horizon. FPA (Flight path angle)is zero in level flight.So...when you increase the camber of the aerofoil ie. by extending flaps and slats the AOA increases and the lift increases thereby creating a buoyancy effect which has to be counteracted by applying down elevator to maintain level flight and a constant FPA. In answer to your question..The AOA increases.
2, As an approximation, use your forefinger to measure distance between 2 waypoints not to far apart on the chart and you will know how many miles your finger measures on a Jepp chart.
3,This is a tricky one.......here is what i feel. A clearway at the end of the RWY will increase your RTOW in the same way as if there was an obstacle close to the RWY one would have to reduce RTOW./ A clearway will have no effect on V1. I will however be open to more logical views.
4, A stopway will increase ASDA 'cos you have more rwy to accelerate and then stop. It will have no effect on TORA.It will increase TODA.
5,As height increases more power is needed to maintain level flight and less power is available. An airplane is said to have reached it's absolute ceiling when full climb thrust is needed to maintain level flight.Service ceiling is defined as the altitude at which the ROC has reduced to a 100fpm.
6, There is no such thing as a critical engine on a jet.
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LYKA,
1. Not quite as simple as that. It is easy to confuse the geometric body angle (as in what the ADI says) with the aerodynamic situation. About all you can say is that, with the altitude and speed constrained, the increased CL for a given alpha (with high lift devices extended) will require a reduction in aerodynamic angle of attack with a corresponding reduction in ADI pitch attitude. To go beyond that you would need to have a look at the particular situation.
TE flaps tend to "lift" the basic wing's CL-alpha curve to a higher CL value at each alpha. LEDs tend to extend the basic wing's curve (with or without TEDs, as appropriate) to higher values of both CL and alpha before the separation roll off becomes evident. This is seen clearly in any basic text, as you would be aware.
3. Declared data is a matter for what the airport authority wishes to permit within the requirements of airports Design Standards.
Generally, clearway will permit an increase in RTOW up to a point where the declared TORA becomes limiting (at which stage additional clearway is of no use). V1 depends on what the intention is for the takeoff analysis and an assessment of all the story, not just the runway declared distances. However, if you were looking to compare the situation between, say, a runway with and without clearway but with the same declared TODA, then you would normally expect to see a lower V1 used in the case with clearway declared.
4. Stopway is nomally included in ASDA, and TODA by virtue of clearway. Generally, the clearway declared will extend beyond the stopway declared and result in an increase in TODA above ASDA.
5. Service ceiling normally is defined as the level where the aircraft has a small residual climb capability, absolute ceiling is of little practical interest.
6. A jet does not usually demonstrate the significant difference which you may see with a propeller aircraft between engine failures on one wing compared to the other. For practical piloting purposes, there is usually no critical engine as such.
The main concern with crosswind during the takeoff is in respect of what is happening in the region of min V1 (which relates to Vmcg). Although there are differences depending on which rules are in vogue for a particular certification, the declared Vmcg relates to light wind conditions.
If there is a strong crosswind, then the directional stability of the aircraft will provide either a stabilising (in the event that the failure is on the lee side) or destabilising (failure on the windward side) yawing moment. So, from a practical pilot's viewpoint, the worry is with a failure on the windward side during a takeoff predicated on V1 being around V1min.
The early 125s had some problems with directional characteristics and the previous post comment is acknowledged. Those aircraft, as I recall, also had Va predicated on rudder input rather than elevator.
The real concern is looking to see whether you can structure the operation to avoid the need for a min V1 takeoff in conditions of strong crosswind.
As a rule of thumb, the declared Vmcg will increase by around half the crosswind.
In the situation where the aircraft takeoff is based on minV1 in strong crosswind conditions, a critical speed failure during the takeoff might well result in the aircraft being directionally uncontrollable unless the operating thrust is reduced. In practice, if control proved to be inadequate, the only reasonable option would be to initiate an RTO.
If the scheduled V1 is greater than the wind corrected Vmcg by any appreciable margin, then the problem becomes progressively insignificant.
[This message has been edited by john_tullamarine (edited 06 July 2001).]
1. Not quite as simple as that. It is easy to confuse the geometric body angle (as in what the ADI says) with the aerodynamic situation. About all you can say is that, with the altitude and speed constrained, the increased CL for a given alpha (with high lift devices extended) will require a reduction in aerodynamic angle of attack with a corresponding reduction in ADI pitch attitude. To go beyond that you would need to have a look at the particular situation.
TE flaps tend to "lift" the basic wing's CL-alpha curve to a higher CL value at each alpha. LEDs tend to extend the basic wing's curve (with or without TEDs, as appropriate) to higher values of both CL and alpha before the separation roll off becomes evident. This is seen clearly in any basic text, as you would be aware.
3. Declared data is a matter for what the airport authority wishes to permit within the requirements of airports Design Standards.
Generally, clearway will permit an increase in RTOW up to a point where the declared TORA becomes limiting (at which stage additional clearway is of no use). V1 depends on what the intention is for the takeoff analysis and an assessment of all the story, not just the runway declared distances. However, if you were looking to compare the situation between, say, a runway with and without clearway but with the same declared TODA, then you would normally expect to see a lower V1 used in the case with clearway declared.
4. Stopway is nomally included in ASDA, and TODA by virtue of clearway. Generally, the clearway declared will extend beyond the stopway declared and result in an increase in TODA above ASDA.
5. Service ceiling normally is defined as the level where the aircraft has a small residual climb capability, absolute ceiling is of little practical interest.
6. A jet does not usually demonstrate the significant difference which you may see with a propeller aircraft between engine failures on one wing compared to the other. For practical piloting purposes, there is usually no critical engine as such.
The main concern with crosswind during the takeoff is in respect of what is happening in the region of min V1 (which relates to Vmcg). Although there are differences depending on which rules are in vogue for a particular certification, the declared Vmcg relates to light wind conditions.
If there is a strong crosswind, then the directional stability of the aircraft will provide either a stabilising (in the event that the failure is on the lee side) or destabilising (failure on the windward side) yawing moment. So, from a practical pilot's viewpoint, the worry is with a failure on the windward side during a takeoff predicated on V1 being around V1min.
The early 125s had some problems with directional characteristics and the previous post comment is acknowledged. Those aircraft, as I recall, also had Va predicated on rudder input rather than elevator.
The real concern is looking to see whether you can structure the operation to avoid the need for a min V1 takeoff in conditions of strong crosswind.
As a rule of thumb, the declared Vmcg will increase by around half the crosswind.
In the situation where the aircraft takeoff is based on minV1 in strong crosswind conditions, a critical speed failure during the takeoff might well result in the aircraft being directionally uncontrollable unless the operating thrust is reduced. In practice, if control proved to be inadequate, the only reasonable option would be to initiate an RTO.
If the scheduled V1 is greater than the wind corrected Vmcg by any appreciable margin, then the problem becomes progressively insignificant.
[This message has been edited by john_tullamarine (edited 06 July 2001).]
As above for the others, however point 2:
I am sure that whoever is asking the question wants to know if you are aware that 1 nm = 1 minute of latitude, so you can measure you distance in NM against any of the latitude scales on the chart.
I am sure that whoever is asking the question wants to know if you are aware that 1 nm = 1 minute of latitude, so you can measure you distance in NM against any of the latitude scales on the chart.
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You forgot to mention Checks any latitude within the nominated standard paralels for any Lamberts conformal conic projection. 
[ 10 July 2001: Message edited by: Slasher ]
[ 10 July 2001: Message edited by: Slasher ]
KYLA Morse code is not correct in answer No1,High lift devices, flaps slats, alter the stall angle. Flaps decrease the stall speed, increase the max lift coe'; and DECREASE the stall angle.
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I think a revisit to typical aerofoil section properties might be in order.
TE and LE devices work a little differently to each other.
TED tend to move the CL-alpha curve to the left, reducing the stalling angle without all that much variation in CLmax.
LED tend to extend the basic curve and increase CLmax and the stalling angle (important for jet takeoff, especially).
One of the problems is that it is easy to confuse body angle (ie ADI) with aerodynamic flow angles.
TE and LE devices work a little differently to each other.
TED tend to move the CL-alpha curve to the left, reducing the stalling angle without all that much variation in CLmax.
LED tend to extend the basic curve and increase CLmax and the stalling angle (important for jet takeoff, especially).
One of the problems is that it is easy to confuse body angle (ie ADI) with aerodynamic flow angles.
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CRITICAL ENG ON A JET.
Lets use a 747-400. Engs are numbered 1>4 L to R as you sit in the cockpit. Taking off on a runway heading N with a max crosswind component coming from E will mean that eng 4 is the critical eng for takeoff. Why is this? Because on T/Off you need lots of left rudder imput because the wind is blowing the tail to the L and the nose to the R. To counter the nose to the R on the roll you put in L rudder. Now number 4 eng fails on the roll meaning that numbers 1/2 engs are pushing the nose R and more L rudder is required to keep straight along the runway. If your speed isn't reasonably fast you will not have a very effective rudder and you may be at max L rudder imput and still be going right and off the edge of the runway. The answer would be to reduce power on the other engines to reduce the assy effect as produced by eng no 4 quitting. Of course eng 3 would also be a problem, but not being so outboard it is not such an assy problem and if 1/2 eng failed it would help reduce rudder imput required due to the wind.
Hope you got all that.
Lets use a 747-400. Engs are numbered 1>4 L to R as you sit in the cockpit. Taking off on a runway heading N with a max crosswind component coming from E will mean that eng 4 is the critical eng for takeoff. Why is this? Because on T/Off you need lots of left rudder imput because the wind is blowing the tail to the L and the nose to the R. To counter the nose to the R on the roll you put in L rudder. Now number 4 eng fails on the roll meaning that numbers 1/2 engs are pushing the nose R and more L rudder is required to keep straight along the runway. If your speed isn't reasonably fast you will not have a very effective rudder and you may be at max L rudder imput and still be going right and off the edge of the runway. The answer would be to reduce power on the other engines to reduce the assy effect as produced by eng no 4 quitting. Of course eng 3 would also be a problem, but not being so outboard it is not such an assy problem and if 1/2 eng failed it would help reduce rudder imput required due to the wind.
Hope you got all that.
