CarlosT 7 Posted December 22, 2012 Share Posted December 22, 2012 +1 Link to comment Share on other sites More sharing options...
Rafal Haczek 1612 Posted December 22, 2012 Share Posted December 22, 2012 Guys, the arrow voting system has been reintroduced. Why don't you use it to show you like the idea? Adding '+1' posts is annoying for everyone who follows this thread. Link to comment Share on other sites More sharing options...
galaio 16 Posted December 22, 2012 Share Posted December 22, 2012 Guys, the arrow voting system has been reintroduced. Why don't you use it to show you like the idea? Adding '+1' posts is annoying for everyone who follows this thread. One vote for Rafal. Hello mate Link to comment Share on other sites More sharing options...
Patrick1246 353 Posted December 22, 2012 Share Posted December 22, 2012 Gents, what is now the Problem, wrong FLX from FMGS or wrong N1 setting ? I always use TOPCAT for FLX, because AXE calculated that a bit wrong. I compare the N1 Setting with Tables, I can't see any Problems, I'm sure ouer Bus has correct N1 for FLX and TOGA Link to comment Share on other sites More sharing options...
Alex Jefferies 17 Posted December 23, 2012 Share Posted December 23, 2012 Hi Patrick, I think the N1 values are correct, they are generally within 0.2% of TOPCAT which is very good; however the thrust output vs. N1 doesn't seem to be quite right i.e. low thrust for a given N1 value. E.g. TOPCAT says FLX T/O with 83.7% N1 is sufficient given the field length and conditions yet the AXE struggles to make Vr by the opposite threshold. I've taken to taking about 10*C off any TOPCAT value for use in the AXE, or just going TOGA full-time. The alternative is that the AXE is correct, and that the TOPCAT calculations are somehow wrong. It's hard to tell without more data. Alex Link to comment Share on other sites More sharing options...
auss81 2 Posted December 23, 2012 Share Posted December 23, 2012 For me TOPCAT is working just fine calculating AXE FLX TO. I use the wilco profile as a reference for TOPCAT, however I use it only in the Take off page getting the current gross weight. I have only to adjust 1°C less the computation to have a perfectly reliable TO power. Link to comment Share on other sites More sharing options...
Jarkko 39 Posted December 23, 2012 Share Posted December 23, 2012 Gents, what is now the Problem, wrong FLX from FMGS or wrong N1 setting ? I think the N1 values are correct, they are generally within 0.2% of TOPCAT which is very good ... AXE struggles to make Vr by the opposite threshold. In flaps 3 scenario, the simulated Airbuses TOGA performance equaled Topcat Flex +58 takeoffs. Hello Patrick! Alex summed up the current "problem". (I also agree that the N1 values match extremely well!) The "problem" now is that the AXE uses about 2000-3000ft more runway during takeoffs than predicted by Topcat. To give you an example: TAKE-OFF KSAN/SAN RWY 27 TORA 9401FT US-7141 AIRBUS 320-214 CFM56-5B4 SAN DIEGO INTERNATIONAL TEMP +15C ALT 29.92 WIND 345/00 (00KT HW) ------------------ CONDITIONS ------------------- ** CONF 1+F ** NORM T/O ** DRY ** ** AIR COND ON ** ANTI ICE OFF ** ASSUMED TAKE-OFF WEIGHT 145300 LB ------------------ FULL THRUST ------------------- +15C 174744 FIELD 133-141 141 144 3930FT 89.2% ---------------- REDUCED THRUST ----------------- +57C 152869 FIELD 143-145 145 147 1881FT 83.3% +58C 151485 FIELD 144-146 146 147 1708FT 83.2% +59C 150101 FIELD 145-146 146 147 1521FT 83.1% +60C 148719 CLIMB 146-147 147 148 1267FT 82.9% //+61C 147337 CLIMB 147-148 148 149 952FT 82.8% +62C 145894 CLIMB 148 149 149 516FT 82.7% +63C NOT AUTH *************************************************** DO NOT EXCEED MAX STRUCT TAKE-OFF WGHT OF 169756 LB *************************************************** ------------------ ENGINE OUT ------------------- NONE ---------------------- END ----------------------- I was struggling to make off the runway, even with full thrust, which should have given me a safe 3930FT runway margin. If you feel adventures, you could try the Topcat's suggestion of flex +61, but I'm too scared to try Just to quote Alex: The alternative is that the AXE is correct, and that the TOPCAT calculations are somehow wrong. It's hard to tell without more data. Link to comment Share on other sites More sharing options...
Fabo 41 Posted December 23, 2012 Share Posted December 23, 2012 Hi guys, here you go with a partial Aerosoft Airbus X Extended profile. It can load people and stuff, and it will compute CoG and takeoff trim. it CAN NOT load FUEL, I repeat it CAN NOT load FUEL. You HAVE to do that by HAND. The CoG values are correct however.note: Ability to load fuel is tied to support of Christian Grill of TOPCAT. At this point, I am not optimistic enough to believe he would grant any in any realistic timeframe. Link to comment Share on other sites More sharing options...
Patrick1246 353 Posted December 23, 2012 Share Posted December 23, 2012 Gents, i have tested this a bit On this TO, i can't see any problems, thats really weird. Sorry for meters, at Vr i have 1800m left to the end, and TOPCAT display 1400m margin Link to comment Share on other sites More sharing options...
balus 43 Posted December 23, 2012 Share Posted December 23, 2012 I generally use the first temp that Topcat recommends and so far it has been spot on - loving this bird Link to comment Share on other sites More sharing options...
Jarkko 39 Posted December 23, 2012 Share Posted December 23, 2012 For me TOPCAT is working just fine calculating AXE FLX TO. Gents, i have tested this a bit I generally use the first temp that Topcat recommends and so far it has been spot on - loving this bird OK, this sounds good! This means that I'm doing something wrong. Can you do a following test, so we can compare apples to apples. Aircraft: AXE 320-214 Aer Lingus, Location: KSAN (San Diego International) runway 27, Weather: FSX default Fair weather, time 22.12.2012 day time. Fuel and payload: half of everything: As the aircraft is ready to go on the runway, use taxi fuel for Topcat: Select flaps 2 and flex +45 as this gives us 1000m/3300ft runway margin: Make sure that flaps 2 and FLX 42 is annunciated: How much runway did you have left on takeoff? Thank you very much for your help! Link to comment Share on other sites More sharing options...
Patrick1246 353 Posted December 23, 2012 Share Posted December 23, 2012 1020 meters Link to comment Share on other sites More sharing options...
Jarkko 39 Posted December 23, 2012 Share Posted December 23, 2012 Thanks for the help! I had less than 10m runway left... I'm clearly doing something wrong. I just have to figure out what it is Link to comment Share on other sites More sharing options...
Patrick1246 353 Posted December 23, 2012 Share Posted December 23, 2012 make a screen please after FLX Setting from FMA and Upper ECAM Link to comment Share on other sites More sharing options...
Swen 20 Posted December 23, 2012 Share Posted December 23, 2012 What i do is following: First i setup my weight for flight with ABE Fuelplanner and try to sync at best with topcat: Uploaded with ImageShack.us Next i calc takeoff with topcat Uploaded with ImageShack.us Next i setup fmc with it all Uploaded with ImageShack.us Uploaded with ImageShack.us The only thing i can't trim the plane to 0.5 its an issue. But Calculation and setup works well i think. Try it and give me feedback what you think. Remember that this calc based on wilco airbus with cfm engines. Link to comment Share on other sites More sharing options...
Jarkko 39 Posted December 23, 2012 Share Posted December 23, 2012 make a screen please after FLX Setting from FMA and Upper ECAM I've got some good news and some bad news I removed all FSUIPC axis assignments, mapped all axis again in FSX => no luck. Checked my every action against the Step-by-Step tutorial and... just did 2 flex +45 takeoffs with about 900m runway left. The good news is that AXE and Topcat now match, the bad news is that I have no idea what I was doing wrong Thank you so much for helping me out! Link to comment Share on other sites More sharing options...
Patrick1246 353 Posted December 23, 2012 Share Posted December 23, 2012 No Problem, have fun with the Airbus Link to comment Share on other sites More sharing options...
Max Reverse 344 Posted December 24, 2012 Share Posted December 24, 2012 @ Sven Thanks for your pictures. I've noticed that you used to set T/O without Air Condotion in TOPCAT. Do you also switch them off for T/O? I am asking, because i never did this before, but maybe its better? Link to comment Share on other sites More sharing options...
Swen 20 Posted December 24, 2012 Share Posted December 24, 2012 Yes, its company like. Some switch off some not. I switch off. After take off i switch pack 1 on do some work flow 10 sec later i switch pack 2 on. Link to comment Share on other sites More sharing options...
Max Reverse 344 Posted December 24, 2012 Share Posted December 24, 2012 Thank you, Swen Link to comment Share on other sites More sharing options...
Aprilia 4 Ever 35 Posted December 25, 2012 Author Share Posted December 25, 2012 thank you for that file but is it "normal" that I'm always getting a nose down trim? could you make a file for the A321? Link to comment Share on other sites More sharing options...
Fabo 41 Posted December 25, 2012 Share Posted December 25, 2012 Hello, The trim is fully dependant on Centre of Gravity. The position for 0.0 trim is at about 27% MAC. Anything more will mean that negative trim is in order, which is quite normal. TOPCAT will try to load more towards the rear, as this is beneficial for aerodynamics and lowers total fuel consumption (if you would like further explanation, drop me a PM, but this can take a rather long time to explain, and I need some illustrations I dont have at hand). Anyway so while default value put in the FMGS is ZFCG at 25% MAC, that corresponds to about 0.8 units uptrim, this is not actually what the loadmanager loads (even if it loads somewhat front heavy). TOPCAT will load more for tail, for example ZFCG at 30% MAC. That can then mean up to TOCG of 36% MAC. IIRC, this aft-heavy loading is called "trimming for performance" or "loading for performance" in the industry, and usually an airline will tell you where ideally will they want their ZFCG to be at. (some like it as far aft as possible, some with more margin). Also, if you were wondering why you got such a high number, when usual CoG in a 737 is in mid 20s, the reason is FBW. More aft the CG is, less stable the airplane is, and this could be problematic in non-FBW airplanes. (as an aside, if you know MD-11s LSAS, this is what it is for). As per A321: TOPCAT does not support the type A321 and regarding adding any Airbus types: Not gonna happen, unfortunately source performance data for Airbus airplane are pretty much impossible to obtain. Link to comment Share on other sites More sharing options...
Aprilia 4 Ever 35 Posted December 26, 2012 Author Share Posted December 26, 2012 I'm a former ATPL studentpilot so I'm aware of priciples of flight etc but I had some jumpseat training flights (a320, a321 and a330) and at all these flights the Trim was UP, so that's the reason why I was asking. best regards Link to comment Share on other sites More sharing options...
Fabo 41 Posted December 27, 2012 Share Posted December 27, 2012 Oh, sure. But many guys are not, and dont always really understand what is going on with what. Weight&Balance does seem to be one of the things that are often overlooked by simmers as marginal, while it actually is quite substantial to the flight. Anyway I have no experience with A321 or A330, so I dont know how the typical number looks there, but in case of A320, 0 trim is at those 27% MAC. Maune the airline you jumped with has a different, nose-gheavy prefering techniques. BRGDS Peter Link to comment Share on other sites More sharing options...
Swen 20 Posted December 27, 2012 Share Posted December 27, 2012 Topcat is ok. If you use Wilco A320 you dont get far away data. I cant do that for A321, 'cause im not really sure but there isn't an A321 in Topcat. Trim setting is always round about 1°. But always UP. I dont have many real life expirience, but negativ - down trim - i have never seen. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.