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Leveld B763 - Needs Too Much Power?  
User currently offlineSevenHeavy From United Kingdom, joined Mar 2004, 1156 posts, RR: 10
Posted (6 years 5 months 1 week 1 day 4 hours ago) and read 8111 times:

Hoping for some opinions on this one....

I've had the LevelD B763 for a couple of years and I've just gone back to using it after a while on PMDG stuff. I can't remember whether it was like this all along but it seems to me that an unrealistic amount of thrust is needed when taxiing on the ground. Even at relatively light weights 45-50% N1 is required to get the aircraft moving and this goes up to almost 60% when at MTOW. Even take off thrust seems excessive - derated take offs are much more sluggish than I believe they should be and I'm using 110% just to get airborne

I'm wondering if I have unwittingly done something to the FDE?. Does anyone else think the same or has had a similar issue? is there a way to adjust the power settings within the aircraft.cfg?

I remember from a thread on here (which I now can't find!!) of an update for the FDE to increase the power when using reverse thrust. I updated my FDE accordingly and I wonder if this could have influenced any other power settings.

Grateful for any opinions or suggestions.

Regards


So long 701, it was nice knowing you.
17 replies: All unread, jump to last
 
User currently offlineQantas744ER From United States of America, joined Jun 2005, 1288 posts, RR: 4
Reply 1, posted (6 years 5 months 1 week 1 day 2 hours ago) and read 8096 times:

Hey, use to feel the same when I started off with my PMDG and LDS planes. And for the taxi thrust there is a simple answer. Microsoft simply did not create a very good friction module for fs2004. This means the tires suffer from higher friction then they should. Requiring more thrust then they really should to taxi.

For your takeoff during a derated TO it will feel a little weak on TO depending from your TOW but since that allways changes there is no general power setting you should use. Look for a takeoff performance calculator for the LDS763 were you can enter weight, wind, pressure, temp and the specific airport and runway and the prog will tell u what de rate and assumed temp to use. It can even give you the optimal flap setting and tell you approx. How much runway you will need.

The 763 has a lot of power and even at MTOW at most conditions full thrust should not be required. BTW do you only derate or also use a assumed temp. ? Do you use TOGA on TO?

And don't change anything in the .cfg except for the power of the engines in lbs. What I do is check under the FAA TCDS for the specifc thrust on a certain engine I am flying on that airline and the. Enter it in the aircraft.cfg for that flight to make it as realistic as possible.

Excuse my spelling but written from my iPhone.

Leo



Happiness is V1 in Lagos
User currently offlineRyanair737 From , joined Dec 1969, posts, RR:
Reply 2, posted (6 years 5 months 1 week 23 hours ago) and read 8081 times:

I think you might have done something to the FDE without knowing, on very light weights my Leveld 767 doesn't need any thrust to start moving and when heavy only needs about 40-45% I would say which is true to the real thing.

I would check your settings out.


User currently offlineSevenHeavy From United Kingdom, joined Mar 2004, 1156 posts, RR: 10
Reply 3, posted (6 years 5 months 1 week 20 hours ago) and read 8069 times:

Thanks guys- Ryanair - the figures you quote are more in line with what I remember.

My next question is, are there any obvious places to start to find the problem with the FDE? I have limited experience of updating the .cfg's but I am familiar with the process.

Regards



So long 701, it was nice knowing you.
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 4, posted (6 years 5 months 1 week 20 hours ago) and read 8069 times:



Quoting Qantas744ER (Reply 1):
This means the tires suffer from higher friction then they should. Requiring more thrust then they really should to taxi.

Wheel bearings, surely? Tyres should offer as much friction as possible. In any case, other publishers seem to have worked around it.

Quoting Qantas744ER (Reply 1):
For your takeoff during a derated TO it will feel a little weak on TO depending from your TOW but since that allways changes there is no general power setting you should use. Look for a takeoff performance calculator for the LDS763 were you can enter weight, wind, pressure, temp and the specific airport and runway and the prog will tell u what de rate and assumed temp to use.

Doesn't the LDS 763 have an FMC to give a huge helping hand in such matters... assuming it's set up correctly?


User currently offlineCptSpeaking From United States of America, joined Apr 2006, 639 posts, RR: 1
Reply 5, posted (6 years 5 months 1 week 8 hours ago) and read 8047 times:



Quoting SevenHeavy (Reply 3):
My next question is, are there any obvious places to start to find the problem with the FDE? I have limited experience of updating the .cfg's but I am familiar with the process.

Re-installing the airplane would probably be your best bet...

I hadn't flown the 763 in a while and when I got on the other night, it was all screwy, and I only had the default Level D 32 bit textures, and nothing else...did a re-install of the 763 and it was fine after that...just had to reinstall my add-on textures again and it was good to go...



...and don't call me Shirley!!
User currently offlineQFA380 From Australia, joined Jul 2005, 2062 posts, RR: 1
Reply 6, posted (6 years 5 months 6 days 10 hours ago) and read 8010 times:

I also often feel that the Level-D might have something up, it does take quite a large amount of thrust just to get it moving. I normally just throttles to the metal though for take-offs, don't really care how much virtual fuel I'm using.

Quoting David L (Reply 4):
Doesn't the LDS 763 have an FMC to give a huge helping hand in such matters... assuming it's set up correctly?

The FMC doesn't figure that stuff out for you, it just allows you to enter it and then it will control the power during take-off. Real pilots I assume either work this out for themselves with runway length, weight and atmospheric conditions in those massive flight manuals or they have a special calculator or they might just ask dispatch.


User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 7, posted (6 years 5 months 6 days 9 hours ago) and read 8006 times:



Quoting QFA380 (Reply 6):
The FMC doesn't figure that stuff out for you, it just allows you to enter it and then it will control the power during take-off.

I'm not saying it does it all for you, I'm saying that if you use it properly, you remove a lot of extra work.


User currently offlineRyanair737 From , joined Dec 1969, posts, RR:
Reply 8, posted (6 years 5 months 6 days 6 hours ago) and read 8001 times:

All the FMC does with regards to thrust in the 757/767 it allows you to enter your takeoff thrust temperature and that is about it. The Thrust Management System (TMS) near the engine display does the majority of the thrust management in the 757/767.

User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 9, posted (6 years 5 months 6 days 2 hours ago) and read 7980 times:



Quoting Ryanair737 (Reply 8):

I guess I've been spoiled by the PMDG 744X.  Smile


User currently offlineQantas744ER From United States of America, joined Jun 2005, 1288 posts, RR: 4
Reply 10, posted (6 years 5 months 6 days 1 hour ago) and read 7970 times:



Quoting David L (Reply 4):

Doesn't the LDS 763 have an FMC to give a huge helping hand in such matters... assuming it's set up correctly?



Quoting David L (Reply 7):

I'm not saying it does it all for you, I'm saying that if you use it properly, you remove a lot of extra work.

There is a difference bewtween a de-rated takeoff and a takeoff with assumed temp. + a de-rated setting. A normal de-rate being chosen from the FMC will not be even close to optimal for the takeoff .

Pilots use only the minimum thrust required for their takeoffs. This to save fuel, wear to the engines etc. This minimum thurst is a combination of assumed temp and a de-rated setting. But the FMC cannot give you this data. So it is calculated by the crews with either charts, dispatch over ACARS (thats how its mostly done in the US) or by having laptops with the software on them.

For example at x weight x wind x temp on x runway length with xobstacles the plane requires 1.30EPR to complete the TO successfully the 2 de-rate options in the FMC will give you 5% 10% and de-rate for example. 5% might give you 1.52EPR 10% 1.41EPR This because these de-rate settings rely on the real outside temp which at full takeoff thrust might give you 1.60EPR at x temp. So why not use a assumed temp.? This will get you the closest to 1.30 EPR together with a de-rate setting.

Quoting David L (Reply 4):
Wheel bearings, surely? Tyres should offer as much friction as possible. In any case, other publishers seem to have worked around it.

Wrong. Tyres will offer a certain friction. But when friction is too much then the plane will of course require more thrust to get it rolling then in real life. And this is exactly the problem with FS2004 the friction is much too high. My proof is that with a PW4056 744 such as UA,SQ,MH etc. operate (i have changed the thrust setting in the .cfg to match the thrust of the PW4056 so 56,750Lbs as to the 58,000Lbs it currently has for all 3 models as this is the max. thrust provided by the GE CF6-80C2BF1) When at MTOW i need 42-45% N1 to get my plane rolling and then around 41 to 42% to keep it going.

Philsquares, member of this forum and SQ 744 captain also flying with PW4056 engines stated how using more than 40% N1 on the 744 for taxi is pretty dangerous as the exaust temps. get very high.

Try the same!

Other example, a real 737 will roll foward slowly at low weights and idle thrust. Take the PMDG 737 at a low weight hit F1 to make sure you really are using idle thrust (incase you have a throttle quadrant etc.) and check if the plane rolls foward. Again this wont happen.

As it seems the issue with the thread starters 763 is related to a bad? FDE update then it does make sence. But if you would like to have a better and more detailed read about the issue with the friction in FS2004 just google it up. There is even a alternative .dll that someone created requiring a more realistic thrust setting for taxi, but as the LDS and PMDG developers have confirmed this creates a whole bunch of other unrealistic issues with brake distance etc. as the brakes on the LDS and PMDG planes have been adapted to be realistic even with the increased friction that FS2004 creates.

Leo  Smile



Happiness is V1 in Lagos
User currently offlineSevenHeavy From United Kingdom, joined Mar 2004, 1156 posts, RR: 10
Reply 11, posted (6 years 5 months 5 days 8 hours ago) and read 7942 times:



Quoting Qantas744ER (Reply 10):
My proof is that with a PW4056 744 such as UA,SQ,MH etc. operate (i have changed the thrust setting in the .cfg to match the thrust of the PW4056 so 56,750Lbs as to the 58,000Lbs it currently has for all 3 models as this is the max. thrust provided by the GE CF6-80C2BF1) When at MTOW i need 42-45% N1 to get my plane rolling and then around 41 to 42% to keep it going.

How do you go about changing the .cfg's? Do you create a seperate one for each engine type or just amend it each time you fly a particular type?

Thanks



So long 701, it was nice knowing you.
User currently offlineQantas744ER From United States of America, joined Jun 2005, 1288 posts, RR: 4
Reply 12, posted (6 years 5 months 4 days 1 hour ago) and read 7897 times:

hey sevenheavy, all I do is change it for the particular flight, but it only takes 5 seconds and I hardly need to change it. And knowing the max thrust ratings by heart is even better. If you need some for certain operators on the PMDG 737/744 or LDS 763 I will tell you what airline uses what engine at what thrust rating. Feel free to ask.


Leo



Happiness is V1 in Lagos
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 13, posted (6 years 5 months 4 days 1 hour ago) and read 7894 times:



Quoting Qantas744ER (Reply 10):
Wrong. Tyres will offer a certain friction. But when friction is too much then the plane will of course require more thrust to get it rolling then in real life.

If you reduce the tyre friction you risk slipping. Tyres are designed to offer as much friction with the surface as possible. Wheel bearings are designed to have as little friction as possible. To take an extreme example: if tyre friction was zero, you'd have no traction on the runway, therefore no directional stability if there was even the slightest camber on the taxiway/runway and your brakes wouldn't do anything either. If the wheel bearing friction is too high, on the other hand, you'll need more thrust to get moving.


User currently offlineCptSpeaking From United States of America, joined Apr 2006, 639 posts, RR: 1
Reply 14, posted (6 years 5 months 3 days 22 hours ago) and read 7885 times:



Quoting David L (Reply 13):

I started to post yesterday about this, going into the differences between static and dynamic friction, then I thought I could probably spend my time better  Smile



...and don't call me Shirley!!
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 15, posted (6 years 5 months 3 days 8 hours ago) and read 7858 times:



Quoting CptSpeaking (Reply 14):

I thought of referring to the notorious Conveyor Belt thread but thought better of it.  crazy 

Qantas744ER: there might be a property which MS calls tyre friction but, if it's "too high", it can't actually be tyre friction - that's all I'm saying.  Smile


User currently offlineQantas744ER From United States of America, joined Jun 2005, 1288 posts, RR: 4
Reply 16, posted (6 years 5 months 2 days 14 hours ago) and read 7833 times:



Quoting David L (Reply 15):

Qantas744ER: there might be a property which MS calls tyre friction but, if it's "too high", it can't actually be tyre friction - that's all I'm saying. Smile

Regarding the actual tyre friction i was 100% wrong and you are 100% right. Thats just what the file is named that creates the issues in FS9.

I stand corrected!

Leo  Smile



Happiness is V1 in Lagos
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 17, posted (6 years 5 months 2 days 8 hours ago) and read 7826 times:



Quoting Qantas744ER (Reply 16):
Regarding the actual tyre friction i was 100% wrong and you are 100% right.

I'd say we both had valid points. The difference is that you were dealing with the issue under discussion and I was being pedantic.  biggrin 


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