Flightdeck Solutions Forum Index Flightdeck Solutions
Technical Support Forum
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

S-A 737-800 FLIGHT PLANNING

 
Post new topic   Reply to topic    Flightdeck Solutions Forum Index -> Sim-Avionics Support
View previous topic :: View next topic  
Author Message
Banananav



Joined: 08 Oct 2015
Posts: 76
Location: 5nm West of RAF Cranwell

PostPosted: Mon Jun 17, 2019 1:57 pm    Post subject: S-A 737-800 FLIGHT PLANNING Reply with quote

Dear All

I've had my Jetmax 737 now for nearly three, very enjoyable, years. As an ex-RAF Navigator I would plan my trips using the (PMDG) FCOM tables. I quickly found that I would always land with much more fuel than planned and that the ac would not perform a Vnav Path descent without significant extra drag.

To cut a long story short, after much experimentation I found that using a Parasite Drag Scalar of 1.27 (instead of the 1.05 in the flight tuning section of the aircraft.cfg file) I was getting consistent on-speed and profile VNav descents and the cruise N1s were much more accurate. I also tweaked the engine fuel flow scalar to tune the cruise fuel flows.

Then Mark pointed out Sim-Brief which, according to FlightDeck2Sim (a current 738 captain on Youtube) is almost exactly what his operator uses. So I flew a series of trips using CI 30 with 0% factor and further tuned the fuel flow scalar.

My last trial trip today - Brisbane to Perth in nil-wind ISA conditions with a fuel flow scalar of 0.98 (originally 0.95) gave a Sim-brief planned time of 04:41 and 27436 lbs of fuel used - the actual time flown was 04:42 and 27556 lbs used (from Aivlasoft EFB flight log). This puts the Sim-Brief hourly fuel flow and the actual one within 0.3% of each other. I have had similar results with these settings on other, shorter range, trips.

In summary, I am now using the following figures to get very accurate flight performance and fuel useage:

Parasite Drag Scalar = 1.27
Fuel Flow scalar = 0.98
Cost Index = 30 (FMC & Sim-Brief)
Sim-brief fuel flow correction = 0%

I hope fellow 738 fliers find these numbers useful.

Regards

Chris
_________________
Chris Finn

Jetmax 737-800 & TQ
P3D 4.5 HotFix2
S-A 1.961
FSUIPC 5.152
Back to top
View user's profile Send private message
jackpilot
Site Admin


Joined: 25 Apr 2004
Posts: 1024
Location: Montreal

PostPosted: Mon Jun 17, 2019 3:26 pm    Post subject: Reply with quote

Thank you...will try.
Jack
_________________
Jack
Full B737-800 DSTD/Sim-Avionics P3d4
ALL FDS & OEMs (+custom TQ)
Back to top
View user's profile Send private message
kand



Joined: 03 Feb 2016
Posts: 185
Location: Buckinghamshire, UK

PostPosted: Mon Jun 17, 2019 5:02 pm    Post subject: Reply with quote

You will never get accurate FB in any MS iteration of fsim, simply because the sim engines still burn fuel from net thrust, not gross, it has been broken for years.

You will get close for 1 particular weight/regime of flight but thats about your lot

I have rewrittrm my own 777 ER airfile to get closer RW perf but its still flawed
Back to top
View user's profile Send private message AIM Address
Jetcos



Joined: 30 Sep 2005
Posts: 1223
Location: Newmarket,Ontario

PostPosted: Mon Jun 17, 2019 7:24 pm    Post subject: Reply with quote

Thanks Chris, will give that a try.
_________________
Steve Cos
Vice President and Tech Support
Flightdeck Solutions (FDS)
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    Flightdeck Solutions Forum Index -> Sim-Avionics Support All times are GMT - 5 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group