Archived

This topic is now archived and is closed to further replies.

2009

MD-11, Vmin, amber foot

Recommended Posts

Issue:A/C weight 260 tons, clean config, speed near the amber foot: if you now fly a turn with 30 deg bank maitaining level flight, the amber foot is not moving up (towards a higher min speed) at all.I have tried different configs, but it is not moving. Only after passing 45 deg bank I notice a reaction of the amber foot.I think there is a little bug here.RGDSTOM

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Amber foot?What specifically are you testing? I think you are referring to higher stall speeds in a turn, and you are testing that the PFD speed tape symbology includes this affect. Could be a little bug, or could be that is accurately models the real aircraft.... if you provide a few more details such as IAS, altitude, temp and indications there might be something to look at.

Share this post


Link to post
Share on other sites
Amber foot?What specifically are you testing? I think you are referring to higher stall speeds in a turn, and you are testing that the PFD speed tape symbology includes this affect. Could be a little bug, or could be that is accurately models the real aircraft.... if you provide a few more details such as IAS, altitude, temp and indications there might be something to look at.
Just take a standard day 15 deg/ 1013. The rest of the conditions I described above. The real plane, the amber band in the PFD will change since the stall speed changes during a turn- this is the reason for an additional speed ( Vmin + 20kts, while flying clean until Flaps 15)- this is about the amount, the amber foot will move up during a turn (max 30 deg bank).This is good enough for normal ops, because after selecting Flaps 28, the maneuvering is already completed.In the PMDG Sim it does not move at all until the bank is exceeding 45 deg.TOM

Share this post


Link to post
Share on other sites

Thanks, Tom. I will forward to the team and see if the item can be vetted.

Share this post


Link to post
Share on other sites
Thanks, Tom. I will forward to the team and see if the item can be vetted.
Thanks Dan!

Share this post


Link to post
Share on other sites

Tom,The yellow band marks minimum certified speed for required g-limit. That ofcourse includes BANKS ! This is not a Boeing. It is not the stick shaker limit. In fact the stick shaker is somewhere between red and yellow (around 70% of the difference, depends on AoA). Vref for example is top of yellow. You cannot have a floating Vref as a function of bank. The equivalent for a Boeing would be for the yellow zone to extend all the way to the manouverability green marker on the speed tape and for an Airbus all the way to dot speed.Hope this clears the issue.A request : I would be greatful if phrases such as "I think is a bug" were included in text with a lot of caution. It is quite evident that Michael and to a smaller extent Yours Trully went out of our way to include features unlikely to be discovered by 90% of simmers, who do not even read the manuals, after 1000 flights. This little feature would be way too gross to overlook right ?Thank youVangelis

Share this post


Link to post
Share on other sites
Tom,The yellow band marks minimum certified speed for required g-limit. That ofcourse includes BANKS ! This is not a Boeing. It is not the stick shaker limit. In fact the stick shaker is somewhere between red and yellow (around 70% of the difference, depends on AoA). Vref for example is top of yellow. You cannot have a floating Vref as a function of bank. The equivalent for a Boeing would be for the yellow zone to extend all the way to the manouverability green marker on the speed tape and for an Airbus all the way to dot speed.A request : I would be greatful if phrases such as "I think is a bug" were included in text with a lot of caution. It is quite evident that Michael and to a smaller extent Yours Trully went out of our way to include features unlikely to be discovered by 90% of simmers, who do not even read the manuals, after 1000 flights. This little feature would be way too gross to overlook right ?Thank youVangelis
Dear Vangelis: I wont call it a bug anymore- that is what you want? I am sorry for that!Than it is a minor mistake, ok? PMDG is aiming high- so it should be just a contribution to make this product even better as it is already.All what I said in my post before is correct- the yellow band is moving with the different g-load during a turn.I am pretty sure there will be pilots to confirm that fact- may be there are some who you can ask- than you may want to correct your statement here.Many Thanks!TOM

Share this post


Link to post
Share on other sites

Tom: Your observation and feedback is appreciated. The Vmin (or whatever it is called) indication should move with the varying wing loads imposed by the banking turns... now the issue is considered a "requested feature" and given time and resources these are seriousely considered by the developers.

Share this post


Link to post
Share on other sites
Tom: Your observation and feedback is appreciated. The Vmin (or whatever it is called) indication should move with the varying wing loads imposed by the banking turns... now the issue is considered a "requested feature" and given time and resources these are seriousely considered by the developers.
Thanks again Dan, I was hoping, that this going to be understand as a help for the developers not as pure criticism.RGDS TOM

Share this post


Link to post
Share on other sites
Dear Vangelis: I wont call it a bug anymore- that is what you want? I am sorry for that!Than it is a minor mistake, ok? PMDG is aiming high- so it should be just a contribution to make this product even better as it is already.All what I said in my post before is correct- the yellow band is moving with the different g-load during a turn.I am pretty sure there will be pilots to confirm that fact- may be there are some who you can ask- than you may want to correct your statement here.Many Thanks!TOM
There's indeed some room for improvement here.Vss is g-load dependent,and indicating as such. Vmin is indicating a static value during turns, iso 1.3 VstallFrom the real plane I remember this Vmin increasing during turns.Regards,Harry

Share this post


Link to post
Share on other sites
Thanks again Dan, I was hoping, that this going to be understand as a help for the developers not as pure criticism.RGDS TOM
Tom,I do have to apologise. I received confirmation about this from a tech advisor about only 7 months later of discussion of what exactly is what. A fix takes 3 seconds (reinsert code that was removed out back in July when Michael and I asked precisely the same question you did, see ?). It is so gross to overlook and so freaking easy to implement (the 744 has it ofcourse) that I believed that it could not have possibly been missed by anyone. My fault with respect to the latter.Thanks again ! (and sorry...)Vangelis

Share this post


Link to post
Share on other sites
Tom,I do have to apologise. I received confirmation about this from a tech advisor about only 7 months later of discussion of what exactly is what. A fix takes 3 seconds (reinsert code that was removed out back in July when Michael and I asked precisely the same question you did, see ?). It is so gross to overlook and so freaking easy to implement (the 744 has it ofcourse) that I believed that it could not have possibly been missed by anyone. My fault with respect to the latter.Thanks again ! (and sorry...)Vangelis
Hi Vangelis, thanks for that kind reply and that background information!We all know, to get a simulation close to the real one, is a very, very complicated thing to do, but with the PMDG MD-11 you are on a good way to achieve that! Plus: a lot of people here in this forum will provide great support and information.Thanks, TOM

Share this post


Link to post
Share on other sites