PikalaxALT 19 Posted November 13, 2014 Share Posted November 13, 2014 I just bought the new A320/A321 and took it for a test flight KPHL-KDCA. The aircraft was near its maximum landing weight. When taxiing out and in, I noticed that the ground speed would rise very slowly, then suddenly (and without warning) jump 5-10 kts with throttles at ~30% N1. This is a major problem as there are times when slow speed is required, eg. pulling into a parking spot, in line for takeoff. This did not happen in the Airbus X Extended A320, nor does it happen in the A319. Comparisons are based on similar flight conditions: same airports, same weather engine, same computer, with VATSIM connection. I'll try again after giving my PC a second reboot (perhaps FSX is still trying to get used to the new aircraft? it tends to resist change :\). Link to comment Share on other sites More sharing options...
Deputy Sheriffs The Dude 6537 Posted November 13, 2014 Deputy Sheriffs Share Posted November 13, 2014 Did the reboot help? Link to comment Share on other sites More sharing options...
Aerosoft Aerosoft Team [Inactive Account] 51558 Posted November 13, 2014 Aerosoft Share Posted November 13, 2014 Have you tried this change? http://forum.aerosoft.com/index.php?/topic/87941-a320-cfm-model-engine-spool-up-jumping/#entry630376 Link to comment Share on other sites More sharing options...
PikalaxALT 19 Posted November 14, 2014 Author Share Posted November 14, 2014 Thanks for pointing that out Mathijs. Stand by, I'll have the opportunity to test it out this weekend. Link to comment Share on other sites More sharing options...
PikalaxALT 19 Posted November 15, 2014 Author Share Posted November 15, 2014 Mathijs, The Dude, and assorted developers, neither the fix nor the reboot helped. Taxi speed still jumps by 5+ knots instantaneously. Link to comment Share on other sites More sharing options...
IGrant 51 Posted November 16, 2014 Share Posted November 16, 2014 I get this too but it only seems to happen at 3rd party airports that make extensive use of ground polygons. So far I've encountered this at Aerosoft EIDW, UK2000 EGKK (free version) and ISDT's LIRF FSX patched. I have not gotten it at any default airport and have flown UK2000's EGNM free version, FSIAT's LICJ (freeware) and AeroportoRC.com's LICR (freeware) with no issues. Why some of these airports cause it and not others, I am not sure of, but it certainly does seem to have something to do with the use of ground polygons. Perhaps it has something to do with their elevation above actual ground level? Another symptom I spotted was that at airports where this problem occurs, the aircraft will not maintain speed at idle thrust like it usually does while taxiing. These speed 'bursts' seem to coincide with odd thrust surges from the engines. I am taking a totally blind guess here but maybe in regards to the polygon elevation, it is confusing the FADEC programming? I could be (and probably am) wrong, but perhaps idle is adjusted up when the aircraft is on the ground- we all know FSX suffers from poor static thrust and friction issues when it comes to simulating jet behavior on the ground. If the idle had been adjusted to be higher while on the ground but the aircraft wasn't actually 'on the ground' but a few cm above it on a hard polygon, then such adjustments wouldn't trigger. Link to comment Share on other sites More sharing options...
PikalaxALT 19 Posted November 16, 2014 Author Share Posted November 16, 2014 It's definitely AccuFeel. Disabling it solved the problem, and re-enabling it brought the problem back. Link to comment Share on other sites More sharing options...
Deputy Sheriffs The Dude 6537 Posted November 16, 2014 Deputy Sheriffs Share Posted November 16, 2014 Ok, thanks for the info! We will make sure that is mentioned in the manual or as a sticky here. Happy Landings! Link to comment Share on other sites More sharing options...
IGrant 51 Posted November 17, 2014 Share Posted November 17, 2014 Interesting. I will have to try this as well and see if it works. Perhaps it was just dumb luck that I always encountered the problem at add on airports only. Glad this one was tracked down because it really bothers me! Link to comment Share on other sites More sharing options...
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