Thrust sensitive at aproach.

[Staffan]

[font color="#800000" size="2" face="verdana"]
Hi,

First let me whish you all Happy Holidays.

I have a great time in flying the 727. And it seams that I donīt get tired as quick with this jewel, as with many other planes. :-)

However, there is a tiny thing I have noticed............

Is it only me, but I find the 727 very thrust sensitive at aproach. I have a very hard time in keeping a steady aproach speed, even at no wind conditions.

Is this the way the 727 should behave?

Just curious. ;-)

Fly safe,
Staffan Ahlberg
Sweden/Stockholm/ESSA
[font color="#008080" size="2" face="verdana"]PMDG MD-11 Team - Beta tester[/font]

http://www.scandicair.com/images/dc9_banner.jpg

[font color="#5F546A" size="2" face="verdana"]My specs are:
Dell Dimension 4600 P4/3.0 Ghz
512 Mb DDR333 Dual channel memory
128 Mb ATI Radeon 9800 Pro
Omega 2590
DirectX 9.0c
W XP Home with SP1
E171FPb Flat panel monitor 17"
240Gb (2x120) 7200rpm HD

[MaxThrust]

Hi Staffan,

Keeping the fuel flow about 3000 pounds per hour is giving 140kts approach speed here. My typical landing configuration is flaps 30 and weight about 150.000 Lbs.

However, if you fall below 140kts approach speed, increasing pitch adds extra drag and accelerating to 140kts needs a bit higher power than it's anticiaped, this causes Pilot induced thrust oscilations..

I recommend not to fall below 140kts at approach, regardless of weight.

Regards,
Bozhan Özsoy.

[wem]

Hi Bozhan

>>My typical landing configuration is flaps 30 and weight about 150.000 Lbs<<

I thought the maximum landing weight was 142500lbs?

regards

Bob

[MaxThrust]

Bob,

AOM Page 156;

Maximum Landing Weight for -200 Series;

30 Flaps 150,000 Lbs.
40 Flaps 142,500 Lbs.

I've configured my 722 Freighter to 135.000 Lbs ZFW wich is very close to the MZFW. With Alternate, Holding and Reserve Fuel my Landing Weight is very close to the MLW. I must try a ferry flight sometime :)

[amollen]

I remember reading somewhere that real pilots also had this problem when the 727 was first introduced... It doesn't glide real well at idle and then there the engine spool-up time.... so quite a few pilots in the early years found themselves, shall we say, a dot or two beneath the glide slope! Once it was generally known that you need to keep up the power, there was no problem.

[airforce2]

I think it's probably rare to find the cargo load pushing up against the floor load limits...most air cargo doesn't tend to be very dense, and cargo aircraft tend to "cube out" long before they get close to "grossing out."

Back to the original question...it's possible that if you are using a driver with a nonlinear throttle response curve, that throttle response can be tricky in some parts of the throttle range. Most of those curves sacrifice precise control in part of the throttle range to increase it in another.

Another possibility is some nonlinearity or noise in the pot in your throttle itself.

I'm not seeing this problem myself. In fact, the ability to trim to an almost hands-off stable approach is one of the great strengths of this add-on. It flies like an airplane, not a Tie-Fighter. Not that I have anything against Tie-Fighters... :-)

Regards

Bob Scott
ATP IMEL Gulfstream II-III-IV-V L-300
Washington, DC

[Staffan]

[font color="#800000" size="2" face="verdana"]
Thanks guys.

I hardly think that joystick noice is the problem. I have an optical stick with drivers from W XP itself. And I donīt have any problems what so ever with other aircraft (around 30). :-)

I increased the approach speed to 140, and now it is more steady than before. ;-)

Fly safe,
Staffan Ahlberg
Sweden/Stockholm/ESSA
[font color="#008080" size="2" face="verdana"]PMDG MD-11 Team - Beta tester[/font]

http://www.scandicair.com/images/dc9_banner.jpg

[font color="#5F546A" size="2" face="verdana"]My specs are:
Dell Dimension 4600 P4/3.0 Ghz
512 Mb DDR333 Dual channel memory
128 Mb ATI Radeon 9800 Pro
Omega 2590
DirectX 9.0c
W XP Home with SP1
E171FPb Flat panel monitor 17"
240Gb (2x120) 7200rpm HD