Sign in to follow this  
No Ice

How to Increase Profile Drag in settings?

Recommended Posts

Good evening all,

 

Don't suppose anyone knows if you can alter the Profile drag in the NGX settings? I would like to increase it a little. 

 

Many thanks.

 

~Shifty~ 

Share this post


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

Full names required in the PMDG forums please.

 

Short answer: No.  Reason:  PMDG aircraft air model is for the most part based on work done outside the sim platform and those entries are both very important and meaningless to users.

 

EDIT:  Now I am wondering why in the world would you want to do that?  If you are having trouble with speed then best to ask help in that area because there are good techniques available.

Share this post


Link to post
Share on other sites

Full names required in the PMDG forums please.

 

Short answer: No.  Reason:  PMDG aircraft air model is for the most part based on work done outside the sim platform and those entries are both very important and meaningless to users.

 

EDIT:  Now I am wondering why in the world would you want to do that?  If you are having trouble with speed then best to ask help in that area because there are good techniques available.

 

Ah ok, no problem, thanks for a reply anyway Dan. 

 

I personally think decelerating from about 250kts to UP speed doesn't react like the real aircraft. It was only a minor thing anyway, its close enough.  

 

Craig Wilson

 

737-300/800 First officer - Jet2.com

Share this post


Link to post
Share on other sites

Ah ok, no problem, thanks for a reply anyway Dan. 

 

I personally think decelerating from about 250kts to UP speed doesn't react like the real aircraft. It was only a minor thing anyway, its close enough.  

 

Craig Wilson

 

737-300/800 First officer - Jet2.com

 

The real aircraft according to Pilots I have talked to , is pretty slippery and not quick to slow down. 

Share this post


Link to post
Share on other sites

The real aircraft according to Pilots I have talked to , is pretty slippery and not quick to slow down. 

 

I agree with them, Bob, I just think it's overemphasised in the NGX. For example I use "Gates" in the Real world that work well for slowing down into certain airports, these don't seem to work in the NGX in the same wx conditions.  

 

Craig Wilson

 

737-300/800 First officer - Jet2.com

Share this post


Link to post
Share on other sites

If you are a 737-800 first officer, your opinion has certain weight. Maybe this in an issue that could be corrected in the NGX v2.... please contribute with more information regarding NGX realism....

Share this post


Link to post
Share on other sites

If you are a 737-800 first officer, your opinion has certain weight. Maybe this in an issue that could be corrected in the NGX v2.... please contribute with more information regarding NGX realism....

 

...but this somehow invalidates the weight of our entire beta and tech team (the latter requires actual experience on the airframe, and pretty significant experience at that).

 

Not sure I agree with that. Do keep in mind that this is all being done in the confines of Flight Sim.

Share this post


Link to post
Share on other sites

I have toured the factory at CAE in Montreal,  where they manufacture $20 million + full motion simulators for among other manufacturers, Boeing customers. The data that is part of the functioning of their simulators, in the case of Boeing, is given to them by the Boeing company and is derived from many of the actual test flights that Boeing makes on their aircraft after their manufacture. How a $60 simulator program on a $700 PC is going to be exactly the same, would be a mystery to me. From what I have heard from real pilots. the PMDG products are pretty darn close. 

Share this post


Link to post
Share on other sites

 

 


The data that is part of the functioning of their simulators, in the case of Boeing, is given to them by the Boeing company and is derived from many of the actual test flights that Boeing makes on their aircraft after their manufacture.

I'm sure you didn't mean that literally, but Boeing doesn't give CAE the the data. They sell them a licence to use it. In cost terms probably the largest single item supplied, one of main the reasons those sims cost that much. The flight tests used are actually those done during aircraft certification. The same also applies with sims for other aircraft manufacturers such as Airbus, Bombardier and Embraer.

Share this post


Link to post
Share on other sites

I'm sure you didn't mean that literally, but Boeing doesn't give CAE the the data. They sell them a licence to use it. In cost terms probably the largest single item supplied, one of main the reasons those sims cost that much. The flight tests used are actually those done during aircraft certification. The same also applies with sims for other aircraft manufacturers such as Airbus, Bombardier and Embraer.

 

Correct, and I had a lengthy  discussion on this topic alone at CAE. I seem to remember that this data was purchased from Boeing at considerable expense. They even selected data from the most average of the aircraft data they had tested, since all aircraft are rigged a bit differently, they wanted something that was typical. 

Share this post


Link to post
Share on other sites

Correct, and I had a lengthy  discussion on this topic alone at CAE. I seem to remember that this data was purchased from Boeing at considerable expense. They even selected data from the most average of the aircraft data they had tested, since all aircraft are rigged a bit differently, they wanted something that was typical. 

I'm not so sure about that. Different aircraft fly different certification tests. It wouldn't be possible to choose only test data from one average aircraft.

Share this post


Link to post
Share on other sites

I'm not so sure about that. Different aircraft fly different certification tests. It wouldn't be possible to choose only test data from one average aircraft.

 

They were discussing  programming  the 767 ER 400 at the time. They took that data from several 767 400 ERs recorded during Boeing's  very extensive flight tests, compared them, and took what they felt was the best representation of an average 767 and that was the data programmed into  the sim's computers. I spent hours with one of the chief engineers of the company, this was not just a casual conversation that I had. He seemed to know what he was talking about. By the way, the sims cost so much, not just from the expense of the data, but the cost involved in  the entire construction of the simulator.  The hydraulic motion platform for the sim that I eventually got a chance to fly for several hours, cost over $2,000,000 and that was a decade ago ( approximately). Everything in the sim has to be exactly like in the real aircraft, the spring tension and  tactile feel, and sound of each and every switch in the cockpit, for instance has to be the same as the real aircraft. The upholstery on the seats, the tracks that the seats slide back and forth on, the rudder pressure, and control pressures, everything must be identical to the real aircraft. When the sim is finished at the factory, the entire unit has to be disassembled, and boxed up, and shipped to the customer. At the customer's site, it has to be totally reassembled, adjusted, and then it is test flown. It then  has to undergo a test flight by the Airline, and the FAA, before it is certified, the same acceptance procedure that an aircraft undergoes.  

Share this post


Link to post
Share on other sites

They were discussing  programming  the 767 ER 400 at the time. They took that data from several 767 400 ERs recorded during Boeing's  very extensive flight tests, compared them, and took what they felt was the best representation of an average 767 and that was the data programmed into  the sim's computers. I spent hours with one of the chief engineers of the company, this was not just a casual conversation that I had. He seemed to know what he was talking about. By the way, the sims cost so much, not just from the expense of the data, but the cost involved in  the entire construction of the simulator.  The hydraulic motion platform for the sim that I eventually got a chance to fly for several hours, cost over $2,000,000 and that was a decade ago ( approximately). Everything in the sim has to be exactly like in the real aircraft, the spring tension and  tactile feel, and sound of each and every switch in the cockpit, for instance has to be the same as the real aircraft. The upholstery on the seats, the tracks that the seats slide back and forth on, the rudder pressure, and control pressures, everything must be identical to the real aircraft. When the sim is finished at the factory, the entire unit has to be disassembled, and boxed up, and shipped to the customer. At the customer's site, it has to be totally reassembled, adjusted, and then it is test flown. It then  has to undergo a test flight by the Airline, and the FAA, before it is certified, the same acceptance procedure that an aircraft undergoes.  

Bob,

 

I've been involved with designing and building training sims since 1977, so I know exactly what's involved. I've also implemented Boeing aerodynamic data packages on numerous occasions and we've never got to pick and choose what to use. I'm not saying what you were told didn't happen but it isn't the normal practice.

 

As for costs, I stand by what I said.

Share this post


Link to post
Share on other sites

Bob,

 

I've been involved with designing and building training sims since 1977, so I know exactly what's involved. I've also implemented Boeing aerodynamic data packages on numerous occasions and we've never got to pick and choose what to use. I'm not saying what you were told didn't happen but it isn't the normal practice.

 

As for costs, I stand by what I said.

 

So you designed and built sims on a scale that CAE does, a world leader in this technology. . Why do I find that really hard to believe? 

Share this post


Link to post
Share on other sites

Kevin and Bob,

 

From what I understand,  Boeing collects Test data from at least the first four aircraft that are in the Test flight program to get the performance data that is published to provide a more accurate picture of what expected performance should be for a production aircraft.   While there may not be large differences in the aircraft they aren't exactly the same obviously.  I don't think it's presented as multiple packages but an average of the test data that is released.

Share this post


Link to post
Share on other sites

So you designed and built sims on a scale that CAE does, a world leader in this technology. . Why do I find that really hard to believe?

I personally don't build the entire thing of course but I do design the simulation software. Are you calling me a liar Bob?

Share this post


Link to post
Share on other sites

Interesting discussion. But I haven't heard any discussion of the idle thrust of the engines in the actual aircraft, which also contributes to the descent performance at idle. That is also a variable depending on manufacturer.

Share this post


Link to post
Share on other sites

Kevin and Bob,

 

From what I understand, Boeing collects Test data from at least the first four aircraft that are in the Test flight program to get the performance data that is published to provide a more accurate picture of what expected performance should be for a production aircraft. While there may not be large differences in the aircraft they aren't exactly the same obviously. I don't think it's presented as multiple packages but an average of the test data that is released.

Hi Paul

 

Indeed. Though I don't think several test aircraft all fly the same data points. Several aircraft are used to cover all the data points.

 

The released data package is based on the original predicted (theoretical) aerodynamic model and adjusted to match actual test aircraft measurements.

 

There is one data package for each type and variant. However the 767-400ER which Bob referred to might have been a special case in terms of how Boeing flight tested the differences to the base 767 model.

Share this post


Link to post
Share on other sites

Interesting discussion. But I haven't heard any discussion of the idle thrust of the engines in the actual aircraft, which also contributes to the descent performance at idle. That is also a variable depending on manufacturer.

The same principle applies. The aircraft manufacturer will usually have an engine model from the engine manufacturer in their simulation model which they provide to sim manufacturers.

 

It only becomes an issue in FSX because the FSX engine model doesn't account for things like flight idle.

Share this post


Link to post
Share on other sites

I personally don't build the entire thing of course but I do design the simulation software. Are you calling me a liar Bob?

 

I am stating that I spent a great deal of time learning about flight sims and how they  are designed by some of the largest flight sim manufacturers in the world , starting with CAE, Boeing, L3 and others, since my job involved interfacing with these companies and even training some of their workers. I am trying to explain how this is done in the case of CAE, and you are implying that I don't know what I am talking about.   :nea:

Share this post


Link to post
Share on other sites

Kevin,

 

Yes, there is a baseline data set for each aircraft type, and the baseline data set is based on one, individual tail, but for $ you can customise to an elected tail. You can also pay $ to have the various 'options' data sets made available to you.

 

Kevin and Bob,

 

From what I understand,  Boeing collects Test data from at least the first four aircraft that are in the Test flight program to get the performance data that is published to provide a more accurate picture of what expected performance should be for a production aircraft.   While there may not be large differences in the aircraft they aren't exactly the same obviously.  I don't think it's presented as multiple packages but an average of the test data that is released.

This post practically says it all!

Share this post


Link to post
Share on other sites

 

 


Yes, there is a baseline data set for each aircraft type, and the baseline data set is based on one, individual tail, but for $ you can customise to an elected tail. You can also pay $ to have the various 'options' data sets made available to you.

Certainly, but tail number data doesn't extend to changes to the aero data. It relates to specific aircraft configuration.

Share this post


Link to post
Share on other sites

The same principle applies. The aircraft manufacturer will usually have an engine model from the engine manufacturer in their simulation model which they provide to sim manufacturers.

 

It only becomes an issue in FSX because the FSX engine model doesn't account for things like flight idle.

Well, I'm sure you are an expert in sim modeling and I am not, but I dabble. On your point about FSX not modeling flight idle thrust, if you go look at some representative .air files for transport type aircraft you will see that there is non-zero thrust at low N1 throughout the aircraft speed profile. Why is that not idle thrust?

Share this post


Link to post
Share on other sites

Well, I'm sure you are an expert in sim modeling and I am not, but I dabble. On your point about FSX not modeling flight idle thrust, if you go look at some representative .air files for transport type aircraft you will see that there is non-zero thrust at low N1 throughout the aircraft speed profile. Why is that not idle thrust?

 

Research the difference between flight and ground idle.

 

Full names in the forum, please - first and last.

Share this post


Link to post
Share on other sites

I am stating that I spent a great deal of time learning about flight sims and how they  are designed by some of the largest flight sim manufacturers in the world , starting with CAE, Boeing, L3 and others, since my job involved interfacing with these companies and even training some of their workers. I am trying to explain how this is done in the case of CAE, and you are implying that I don't know what I am talking about.   :nea:

Bob,

 

CAE don't do that any differently to any other sim manufacturer. The data available to them from Boeing is the same as that available to any customer. You may have spent time learning how flight sims are designed. I have spent my entire career actually designing and building them and getting them qualified by the FAA, CAA, etc. I've dealt directly with the Boeing data department (also Airbus, Fokker, etc) on a number of projects.

 

With respect, I didn't say you didn't know what you were talking about, I said the process you related about obtaining data from Boeing was not typical. I even conceded that the 747-400ER sims you mentioned might have been a special case, being a rather rare bird. You, on the other hand, said you found it hard to believe what I said was true and haven't retracted that comment.

Well, I'm sure you are an expert in sim modeling and I am not, but I dabble. On your point about FSX not modeling flight idle thrust, if you go look at some representative .air files for transport type aircraft you will see that there is non-zero thrust at low N1 throughout the aircraft speed profile. Why is that not idle thrust?

As Kyle hinted, what I meant was FSX doesn't model different idle settings. There's nothing in the AIR file which allows for a lower idle setting on ground, or multiple idle setting in flight.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this