![]() |
If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
![]()
Hi,
I'm relatively new to FS2004, and I'm just trying to learn to land the 747 using ILS and autopilot. I've set up a flight where I'm just about to capture the glide path at 2000ft at Sydney airport. I have no problem capturing the glide path. Alt switches off on the autopilot when I intercept. However the autopilot was crashing the 747 on landing. It was bobbing the aircraft up and down slightly, which I believe was causing the problem. I started speeds from 140 knots to 200 in increments of 10. 140 falls out of the sky. 170 crashes, 150 is perfect (no crash). Is this a bug or am I missing something vital? Does a real ILS behave this way? Is there an easier way to determine the correct speed? Forgive my ignorance if I'm missing something obvious Thanks, Sammy |
#2
|
|||
|
|||
![]()
On Tue, 05 Jul 2005 14:09:44 GMT, Sammy Yousef
wrote: speeds from 140 knots to 200 in increments of 10. 140 falls out of the sky. 170 crashes, 150 is perfect (no crash). Is this a bug or am I missing something vital? Does a real ILS behave this way? Is there an easier way to determine the correct speed? Forgive my ignorance if I'm missing something obvious Thanks, Sammy Yes approach speed is critical. The key to a good landing is a stabilized approach. Being stabilized farther out makes it easier. Make sure the flaps are set correctly for each airspeed change. Also, you may want turn off the autopilot at 100-200 ft AGL, and flare the plane manually. Most real airliners are not flown to the ground on AP. 170 is too fast and you are hammering it into the ground. 140 is probably stalling, that's the bobbing. |
#3
|
|||
|
|||
![]()
Hi again.
Thanks for the reply. I actually stall and fall out of the sky at 140, but bob at 170 and above. Which is what I don't understand. I can understand hitting too hard but why can't I get stable at a higher speed? Is it because I have flaps set at this speed that the autopilot can't hold a straight approach to the runway? I have no problems at all if I turn off the autopilot and flare manually, even at 170 and above. Thanks again, Sammy S Herman wrote: On Tue, 05 Jul 2005 14:09:44 GMT, Sammy Yousef wrote: speeds from 140 knots to 200 in increments of 10. 140 falls out of the sky. 170 crashes, 150 is perfect (no crash). Is this a bug or am I missing something vital? Does a real ILS behave this way? Is there an easier way to determine the correct speed? Forgive my ignorance if I'm missing something obvious Thanks, Sammy Yes approach speed is critical. The key to a good landing is a stabilized approach. Being stabilized farther out makes it easier. Make sure the flaps are set correctly for each airspeed change. Also, you may want turn off the autopilot at 100-200 ft AGL, and flare the plane manually. Most real airliners are not flown to the ground on AP. 170 is too fast and you are hammering it into the ground. 140 is probably stalling, that's the bobbing. |
#4
|
|||
|
|||
![]()
On Tue, 05 Jul 2005 20:53:29 GMT, Sammy Yousef
wrote: Hi again. Thanks for the reply. I actually stall and fall out of the sky at 140, but bob at 170 and above. Which is what I don't understand. I can understand hitting too hard but why can't I get stable at a higher speed? Is it because I have flaps set at this speed that the autopilot can't hold a straight approach to the runway? I have no problems at all if I turn off the autopilot and flare manually, even at 170 and above. Thanks again, Sammy It's the nose bobbing up & down? Is it only the 747? You may be able to change the .cfg file. Find the recommended IAS for the various flap/gear settings & stick to them. If the pitch & power are set with any given flap & gear configuration, the plane should seek out and hold a stable airspeed, whether climb, level or descent. Now whether this matches the GlideSlope is another thing. If you are too fast, the AP may chase the glideslope, so it pitches down to get lower, penetrates the GS low, then reverses pitch to climb back up to the GS, a vicious cycle.. This happens to human pilots too, pilot induced oscillation, or "porpoising" is one common error. |
#5
|
|||
|
|||
![]()
"S Herman" wrote in message
... On Tue, 05 Jul 2005 20:53:29 GMT, Sammy Yousef wrote: Hi again. Thanks for the reply. I actually stall and fall out of the sky at 140, but bob at 170 and above. Which is what I don't understand. I can understand hitting too hard but why can't I get stable at a higher speed? Is it because I have flaps set at this speed that the autopilot can't hold a straight approach to the runway? I have no problems at all if I turn off the autopilot and flare manually, even at 170 and above. Thanks again, Sammy It's the nose bobbing up & down? Is it only the 747? You may be able to change the .cfg file. Find the recommended IAS for the various flap/gear settings & stick to them. If the pitch & power are set with any given flap & gear configuration, the plane should seek out and hold a stable airspeed, whether climb, level or descent. Now whether this matches the GlideSlope is another thing. If you are too fast, the AP may chase the glideslope, so it pitches down to get lower, penetrates the GS low, then reverses pitch to climb back up to the GS, a vicious cycle.. This happens to human pilots too, pilot induced oscillation, or "porpoising" is one common error. Also make sure you are not too heavy. Your fuel should be around 25%. For sure less than 40%. That may help. What does the flight notes for that aircraft say. I don't fly heavies--too much like being a bus driver :-) Paul |
#6
|
|||
|
|||
![]()
Sammy Yousef a écrit :
Hi, I'm relatively new to FS2004, and I'm just trying to learn to land the 747 using ILS and autopilot. I've set up a flight where I'm just about to capture the glide path at 2000ft at Sydney airport. I have no problem capturing the glide path. Alt switches off on the autopilot when I intercept. However the autopilot was crashing the 747 on landing. It was bobbing the aircraft up and down slightly, which I believe was causing the problem. I started speeds from 140 knots to 200 in increments of 10. 140 falls out of the sky. 170 crashes, 150 is perfect (no crash). Is this a bug or am I missing something vital? Does a real ILS behave this way? Is there an easier way to determine the correct speed? Nope, jumbos land at 150kt. In case you're a bit too high on the slope, add 10-20kt then slow back to 150 when you're at the right alt. Just for your knowledge: normal twin jets commercial planes (b737, a320...) land at 135kt and private jets at 125-130. -- Virez Saddam pour me répondre. Remove Saddam to reply. http://www.charles-de-gaulle.org http://www.francelibre.net http://www.concours-resistance.org |
Thread Tools | |
Display Modes | |
|
|