Stu Antonio 2746 Posted December 28, 2019 Report Share Posted December 28, 2019 fmgc_idle_fac= fmgc_perf_fac= What are those entries in the aircraft config setting? Can't find anything in the Aircraft Options pdf.... Greets, Stu Link to post
Koen Meier 1319 Posted December 28, 2019 Report Share Posted December 28, 2019 Those are the idle/perf values on a/c status page. You can change them in the fltsim.cfg or the a/c status page via arm in the change code. Link to post
Stu Antonio 2746 Posted December 28, 2019 Author Report Share Posted December 28, 2019 I see. But what exactly does it mean for the aircraft? And how do I know what to set here? For example I‘ve downloaded 2 321 liveries, one with =0, the other one with =3. Is this related to airframe age? Link to post
M_i_k_e_V_o_g 167 Posted December 28, 2019 Report Share Posted December 28, 2019 Done by engineering.Perf factor is shown on the ofp though, so if there is a discrepancy it is to be resolved with dispatch and changed if necessary. Amending the PERF factor is made to account for airframe/engine specific deterioration and therefore increased fuel burn from the std. Amending or updating the IDLE factor is to adjust the FM descent profile. If it is thought to be incorrect and the aircraft is descending too early, too late etc. Link to post
Koen Meier 1319 Posted December 28, 2019 Report Share Posted December 28, 2019 in the fslabs it does affect fuelburn but irl only calculations. Link to post
Cathal Kavanagh 47 Posted October 25, 2020 Report Share Posted October 25, 2020 Quick question, should we update the Fuel Factor option on Simbrief with the value for fmgc_perf_fac= ? Or should simbrief be set to a particular setting for accurate fuel burn logging from the flight plan? Link to post
Koen Meier 1319 Posted October 25, 2020 Report Share Posted October 25, 2020 27 minutes ago, Cathal Kavanagh said: Quick question, should we update the Fuel Factor option on Simbrief with the value for fmgc_perf_fac= ? Or should simbrief be set to a particular setting for accurate fuel burn logging from the flight plan? Simbrief should be set to the perf value that the aircraft has but you might need to tweak in the end as the fuel burn isn’t entirely accurate I feel. 1 Link to post
Cathal Kavanagh 47 Posted October 30, 2020 Report Share Posted October 30, 2020 On 10/25/2020 at 10:49 PM, Koen Meier said: Simbrief should be set to the perf value that the aircraft has but you might need to tweak in the end as the fuel burn isn’t entirely accurate I feel. Hi Koen, Any tips on how to calculate additional fuel burn % from the FP when logging burned fuel? I'm trying to get as accurate as possible a fuel factor. Link to post
Simon Kelsey 1086 Posted October 31, 2020 Report Share Posted October 31, 2020 I have to say that as far as the IAE engines are concerned my Simbrief fuel figures are always pretty much spot on, within 100kg or so most of the time, provided the Simbrief fuel factor matches the FMGC PERF factor. I rarely fly the CFMs so I'm not sure how it stacks up for them! 2 Link to post
Camille MOUCHEL 119 Posted October 31, 2020 Report Share Posted October 31, 2020 20 hours ago, Simon Kelsey said: I have to say that as far as the IAE engines are concerned my Simbrief fuel figures are always pretty much spot on, within 100kg or so most of the time, provided the Simbrief fuel factor matches the FMGC PERF factor. I rarely fly the CFMs so I'm not sure how it stacks up for them! i fly only CFM and the same, I did a flight from AZ to B fully managed in climb and descent and speed, and difference was within 100kg, the difference is only due to the taxi fuel, i always plan 200Kg of fuel but most of the time, i used 80-120kg so i always have in avg az surplus of 100kg when taking off Link to post
Michael Gold 3 Posted January 6 Report Share Posted January 6 On 12/28/2019 at 8:03 AM, Stu Antonio said: I see. But what exactly does it mean for the aircraft? And how do I know what to set here? For example I‘ve downloaded 2 321 liveries, one with =0, the other one with =3. Is this related to airframe age? I'd like to come back to this older question in this thread -- how would one go about figuring out what value would be appropriate for the airframe you're doing a config for? Link to post
Stu Antonio 2746 Posted January 6 Author Report Share Posted January 6 2 hours ago, Michael Gold said: I'd like to come back to this older question in this thread -- how would one go about figuring out what value would be appropriate for the airframe you're doing a config for? The real perf factors of each airframe of are usually not made public by the airlines. You will have to make one up, or find a source somewhere to get this value from. Some Virtual Airlines though (ie vEZY), who have access to their real world counterparts, provide very detailed airframe configs including this values.... Link to post
Antti Salo 99 Posted January 7 Report Share Posted January 7 Airframe age gives quite a good ballpark. For a new aircraft it will be around zero, and 20 years will add around 5% of burn. Though in reality it can vary a lot. Even if you had access to the real world figure of a certain airframe, it probably wouldn’t be valid for too long, as IRL the figures are updated at recent intervals and for example an engine change can change it significantly in either direction. 1 Link to post
Dan Parkin 141 Posted January 7 Report Share Posted January 7 I knew of an old airframe operated by a large UK carrier that was notorious for essentially flying sideways if was so knackered. 1 Link to post
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