Attn: Swept Wing Transport Pilots
Gender Faculty Specialist
Originally Posted by Chesty Morgan
And the same can be said of a C152. Make your mark at 60kts and accelerate to 120kts you'd miss!
And the same can be said of a C152. Make your mark at 60kts and accelerate to 120kts you'd miss!
Originally Posted by AluminumDrvr
exactly.. 
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To discuss the "change of speed" issue.
Let's ignore the other axes and consider just pitch. The "dot" therefore represent the relative bearing in pitch alone to the target.
Assume I make the initial "dot" at low speed, say with a pitch attitude of ten degrees. Assuming the "target" is actually level with respect to me, that means the "dot" is ten degrees below the aircraft horizontal through my eyes.
Now, if I maintain speed and keep the dot on the target, there is pretty much total agreement that I (eventually) hit the target.
What if I speed up, causing my AoA to decrease? Assume I instantaneously go to an AoA of 9 degrees. If I now put the "dot" on the target, I get a pitch attitude of 10 degrees, so I get a gamma (climb) of one degree. I begin to go "high" relative to the target. As I begin to climb above the level of the target, the act of placing the dot on the target actually causes my pitch attitude to reduce (since Im now placing the dot below my horizon). Eventually, I'll climb enough so that the target is one degree below my horizon: now the "dot" technique causes me to be at a pitch attitude of 9 degrees, equal to my AoA. I enter level flight.
Now I continue level, but as Im approaching the target I find that it still is dropping below the dot (as my "look down" angle increases). So, in order to keep the dot on the target, I pitch down - bringing my flightpath down towards the target again. I'm going to end up 'wobbling' my way towards the target as I successively over and undercorrect, and I believe (though Ive not worked out the maths) that the average will be, in this case, an approach path inclined downwards about 1 degree (the difference between my AoA when I placed the dot and my current AoA).
Its not the most efficient tracking/homing system, but it will work. The yaw plane is similar.
Let's ignore the other axes and consider just pitch. The "dot" therefore represent the relative bearing in pitch alone to the target.
Assume I make the initial "dot" at low speed, say with a pitch attitude of ten degrees. Assuming the "target" is actually level with respect to me, that means the "dot" is ten degrees below the aircraft horizontal through my eyes.
Now, if I maintain speed and keep the dot on the target, there is pretty much total agreement that I (eventually) hit the target.
What if I speed up, causing my AoA to decrease? Assume I instantaneously go to an AoA of 9 degrees. If I now put the "dot" on the target, I get a pitch attitude of 10 degrees, so I get a gamma (climb) of one degree. I begin to go "high" relative to the target. As I begin to climb above the level of the target, the act of placing the dot on the target actually causes my pitch attitude to reduce (since Im now placing the dot below my horizon). Eventually, I'll climb enough so that the target is one degree below my horizon: now the "dot" technique causes me to be at a pitch attitude of 9 degrees, equal to my AoA. I enter level flight.
Now I continue level, but as Im approaching the target I find that it still is dropping below the dot (as my "look down" angle increases). So, in order to keep the dot on the target, I pitch down - bringing my flightpath down towards the target again. I'm going to end up 'wobbling' my way towards the target as I successively over and undercorrect, and I believe (though Ive not worked out the maths) that the average will be, in this case, an approach path inclined downwards about 1 degree (the difference between my AoA when I placed the dot and my current AoA).
Its not the most efficient tracking/homing system, but it will work. The yaw plane is similar.
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If you are outside the marker (outer marker), at 250 knots, clean. You then draw a dot on the windsheild to correspond with your runway landing spot. Then you change airspeed and slow for landing (forget about flaps and gear). The pitch angle gets higher as you slow, so you drop the nose to keep it on the spot, you sink and hit the ground prior to hitting your spot.
If you are at 250 knots and draw the dot. Accelerate to 400 knots in the dive. Your AOA will decrease so you will need to pitch up in order to keep the dot on target. You will overshoot. You will have to keep the dot off target at a higher airpeed than you first drew the dot in order to hit your target. Plain and simple.
You draw your target at 7000 feet. As you decend the wind changes 30 degrees to the left (or right, depending on hemisphere). You keep your dot on target and "home". You are traveling 8 miles per minute over 5 miles. You'll be lucky if you can home it.
You cannot hit any target unless you maintain a constant airspeed and altitude.Thats why HUD's hae a "Flight Path Indicator" that change with airspeed and configuration.
If you are at 250 knots and draw the dot. Accelerate to 400 knots in the dive. Your AOA will decrease so you will need to pitch up in order to keep the dot on target. You will overshoot. You will have to keep the dot off target at a higher airpeed than you first drew the dot in order to hit your target. Plain and simple.
You draw your target at 7000 feet. As you decend the wind changes 30 degrees to the left (or right, depending on hemisphere). You keep your dot on target and "home". You are traveling 8 miles per minute over 5 miles. You'll be lucky if you can home it.
You cannot hit any target unless you maintain a constant airspeed and altitude.Thats why HUD's hae a "Flight Path Indicator" that change with airspeed and configuration.
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As you say, 'keep the dot on the target' will work wherever the dot is as long as the aircraft has the performance to fly the resulting profile. The misunderstanding seems to be that this cannot work with a particular attitude, and of course this is true. If the dot is near the top of the windscreen the initial control inputs will put the nose down until the dot coincides with the target, the target will then tend to move upward requiring the nose to be raised to maintain the dot on target. This will continue as long as necessary. In the extreme case the ac would perform a series of loops around the target before impact, and many types would not have the performance to maintain the dot on target.
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Originally Posted by AluminumDrvr
a. Several investigators had reported that the presence of beards
caused a decrement in the efficiency on half masks, full masks, and -.
respirators. A Department of Navy study (No. NADC-722110CS) reported an '
average inboard leakage of 16 to 67 percent for military-type crew oxygen
masks when tested with subjects wearing beards to altitudes of 18,000 feet.
Civilian crew oxygen masks vary considerably from these types of masks
because of differences in basic mask designs, suspension systems,.,and
controlling regulators. Consequently, CAMI conducted'research to determine
if the problems noted in these reports would also be present when civil
aviation oxygen equipment was tested.
.... respirator/oxygen (sometimes
referred to as "demand") masks cannot be donned rapidly and do not seal
over beards or heavy facial hair. This lack of a seal could result in a
reduced amount of oxygen in the mask and the entry of smoke or toxic fumes
that could result in reduced crewmember capability and performance.
...This can adversely affect the performance of the mask and reduce crewmember
awareness, capability, and performance.
http://www.airweb.faa.gov/Regulatory...E/AC120-43.pdf
In civil 'airline' flying it was company policy in my last airline to pre-select 'Safety Pressure' on the rapid donning mask during pre-flight check. This ensured that there would be an outward flow of O2/air from the mask to clear the smoke goggles and keep mask free of smoke in the event of smoke/fire in the cockpit.
There were many bearded F4 pilots in the Fleet Air Arm and I've never heard of problems there either.
Sight Line Spin = 0, and closing speed = Intercept.
Regards,
rts
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Im not saying pilots dont wear beards. I know its prohibited by most (if not all) company ops manuals in the US (which are regulatory by nature since it needs FAA approval).
I dont know when you used to fly with a beard, if it was done prior to 1987 (before the study, you mention F-4, but that could be after as well), but it only really takes common sense that you will get a better seal on a smooth face than if you had hair between your face and the mask. No matter how trimmed the beard may be. Unless you're able to get the mask around the beard, such as a short goatee.
As i said, i have never seen any active line pilots in the US with a full beard unless they were piston drivers that dont have a mask on board. There may be many who wear beards abroad. Thats what i was trying to find out. Thanks for the input guys...
I dont know when you used to fly with a beard, if it was done prior to 1987 (before the study, you mention F-4, but that could be after as well), but it only really takes common sense that you will get a better seal on a smooth face than if you had hair between your face and the mask. No matter how trimmed the beard may be. Unless you're able to get the mask around the beard, such as a short goatee.
As i said, i have never seen any active line pilots in the US with a full beard unless they were piston drivers that dont have a mask on board. There may be many who wear beards abroad. Thats what i was trying to find out. Thanks for the input guys...
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FWIW - if you read an NTSB report of any midair, you will find an analysis of the relative position of each aircraft in the other aircraft's field of vision.
And you'll find 98% of the time the collision-bound aircraft are stationary in each other's field of view. Not necessarily straight ahead (except when head-on or overtaking), but fixed on the other's windscreen.
And you'll find 98% of the time the collision-bound aircraft are stationary in each other's field of view. Not necessarily straight ahead (except when head-on or overtaking), but fixed on the other's windscreen.
You cannot hit any target unless you maintain a constant airspeed and altitude.
The 'keep the dot on the target' method will always work. As others have said, it may not be the most efficient interception method but you'll get there in the end (even if the target speed vector is changing) as long as the intercepting aircraft has the performance and manoeuvrability to keep the dot there.
Cant comment on the dot in the screen of a 747 and its relative position, however. Any dot that remains in the same position on the windshield will be one of two things. A potential collision because your RELATIVE bearing remains the same and you will collide.
Or
A bug on the windshield that has already collided.
Or
A bug on the windshield that has already collided.
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Originally Posted by FullWings
If that's true then no-one would ever be able to land...
The 'keep the dot on the target' method will always work. As others have said, it may not be the most efficient interception method but you'll get there in the end (even if the target speed vector is changing) as long as the intercepting aircraft has the performance and manoeuvrability to keep the dot there.
The 'keep the dot on the target' method will always work. As others have said, it may not be the most efficient interception method but you'll get there in the end (even if the target speed vector is changing) as long as the intercepting aircraft has the performance and manoeuvrability to keep the dot there.
Do me a favor.. next time you shoot an approach, stick a piece of gum on the windshield outside the marker corresponding to the touchdown zone markers on the runway of intended landing. Let me know where the piece of gum ends up on a 1/4 mile final with respect to the touchdown zone. Make a video.
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I assume that the said dot is at the centre of the wind screen..
also assume that the pilot is sitting at the normal eye height....
ANY AIRCRAFT....
look at it this way............
If you black out your wind screen leaving just a dot in the middle
THROUGH WHICH YOU CAN SEE.......
and if asked to land it on a r/w in cavok cond.....
can I assume that one can manage it with reasonable accuracy...
if you agree then what you are doing is nothing but keeping the dot on the target.......
also assume that the pilot is sitting at the normal eye height....
ANY AIRCRAFT....
look at it this way............
If you black out your wind screen leaving just a dot in the middle
THROUGH WHICH YOU CAN SEE.......
and if asked to land it on a r/w in cavok cond.....
can I assume that one can manage it with reasonable accuracy...
if you agree then what you are doing is nothing but keeping the dot on the target.......
Last edited by gearpins; 1st Aug 2006 at 12:52.
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'ullo, 'ullo, 'ullo .... Constable J_T here, chaps .. as you know I don't routinely
(a) ban folk for getting out of control
(b) lock threads
although, with sufficient provocation, such protocol could be varied ...
Now, I have slashed and burned some of the posts in this thread (without fear or favour, I might add) as the thing was getting out of control in the past 24 hours without any sign of the autopilot's being engaged ...
Let's all take a Bex, please, have a nice cup of tea and a 30 minute lie down, and come back with more sensible Tech Log attitudes to life ...
My apologies to those whose humorous retorts I have slashed but I try to be scrupulous to the point of ruthlessness in these sorts of circumstances ...
I shall take an extremely dim view if anyone were to go back into my handiwork and vary things .. anyone has any beef with what is left of the earlier posts, please let me know by PM and we can think about it ..
Guys and gals .. Tech Log is not for this sort of infantile nonsense ... plenty of places elsewhere where folks can let their hair down a bit if that's the sort of thing which revs you up a tad ..
(a) ban folk for getting out of control
(b) lock threads
although, with sufficient provocation, such protocol could be varied ...
Now, I have slashed and burned some of the posts in this thread (without fear or favour, I might add) as the thing was getting out of control in the past 24 hours without any sign of the autopilot's being engaged ...
Let's all take a Bex, please, have a nice cup of tea and a 30 minute lie down, and come back with more sensible Tech Log attitudes to life ...
My apologies to those whose humorous retorts I have slashed but I try to be scrupulous to the point of ruthlessness in these sorts of circumstances ...
I shall take an extremely dim view if anyone were to go back into my handiwork and vary things .. anyone has any beef with what is left of the earlier posts, please let me know by PM and we can think about it ..
Guys and gals .. Tech Log is not for this sort of infantile nonsense ... plenty of places elsewhere where folks can let their hair down a bit if that's the sort of thing which revs you up a tad ..
Originally Posted by AluminumDrvr
Do me a favor.. next time you shoot an approach, stick a piece of gum on the windshield outside the marker corresponding to the touchdown zone markers on the runway of intended landing. Let me know where the piece of gum ends up on a 1/4 mile final with respect to the touchdown zone. Make a video.
Not the same.
A concept of alternate ideas.
Get it?
It's blindingly obvious that if you're going so slow as to have a pitch angle that lets the aeroplane run out of either wing or airspeed then you're not going to hit the target.
But with 400kts+ is not exactly a problem is it?
It's really simple concept that a heap of people here have explained different ways.
Originally Posted by john_tullamarine
'ullo, 'ullo, 'ullo .... Constable J_T here, chaps .. as you know I don't routinely
(a) ban folk for getting out of control
(b) lock threads
although, with sufficient provocation, such protocol could be varied ...
Now, I have slashed and burned some of the posts in this thread (without fear or favour, I might add) as the thing was getting out of control in the past 24 hours without any sign of the autopilot's being engaged ...
Let's all take a Bex, please, have a nice cup of tea and a 30 minute lie down, and come back with more sensible Tech Log attitudes to life ...
My apologies to those whose humorous retorts I have slashed but I try to be scrupulous to the point of ruthlessness in these sorts of circumstances ...
I shall take an extremely dim view if anyone were to go back into my handiwork and vary things .. anyone has any beef with what is left of the earlier posts, please let me know by PM and we can think about it ..
Guys and gals .. Tech Log is not for this sort of infantile nonsense ... plenty of places elsewhere where folks can let their hair down a bit if that's the sort of thing which revs you up a tad ..
(a) ban folk for getting out of control
(b) lock threads
although, with sufficient provocation, such protocol could be varied ...
Now, I have slashed and burned some of the posts in this thread (without fear or favour, I might add) as the thing was getting out of control in the past 24 hours without any sign of the autopilot's being engaged ...
Let's all take a Bex, please, have a nice cup of tea and a 30 minute lie down, and come back with more sensible Tech Log attitudes to life ...
My apologies to those whose humorous retorts I have slashed but I try to be scrupulous to the point of ruthlessness in these sorts of circumstances ...
I shall take an extremely dim view if anyone were to go back into my handiwork and vary things .. anyone has any beef with what is left of the earlier posts, please let me know by PM and we can think about it ..
Guys and gals .. Tech Log is not for this sort of infantile nonsense ... plenty of places elsewhere where folks can let their hair down a bit if that's the sort of thing which revs you up a tad ..
Point taken. In the best tradition of Maxwell Smart...
"Sorry about that!"
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Originally Posted by Chesty Morgan
And the same can be said of a C152. Make your mark at 60kts and accelerate to 120kts you'd miss!
Originally Posted by Chiliarch
Not if you keep the dot on the target! It is quite likely that a C152 won't have the power to both accelerate to 120 kts and keep the dot on the target, so as has been said before, you have to work within the limits of the ac, and you may run into an obstacle if the resulting flight path is too extreme. Otherwise, the only circumstance in which you won't hit the target is if it too quick to catch.
We're talking about a very large and very stationary building here.
The Pentagon.
Hani, the terrorist, may not have hit his desired target, but he certainly hit the broad side of a barn.
