FSX and the Mach gauge

[chrisal 9]

HiI'm happily using David Maltby's fine Comet 4 in FSX. All the xml gauges but one work flawlessly.However the Mach gauge reads high - not accurately as it does in FS9.I've tried other of DM's Mach gauges (e.g. his VC 10)but with the same result.Is the mach speed output data different in FSX from FS9?Glad of any helpCheersChris

[WarpD 824]

Without knowing what his gauges use to display (i.e. is it a default FS mach value or not)... we wouldn't be able to say if it's FSX or his gauge.

[tgibson 11]

XML gauges are definitely read differently by FSX than FS9. I was using a VSI gauge that read OK in FS9 but rather bizarrely in FSX (at rest it was 500 fpm low and in motion the VS was never correct or even linear). Found out the gauge was dividing the default VS variable by 1000 and using that to move the needle. By eliminating the division by 1000 and changing the non-linearity table to match, it now works fine in FS9 AND FSX. Very odd - that variable must be exposed to the XML gauge differently somehow.Hope this helps,--Tom GibsonCal Classic Propliner Page: http://www.calclassic.comFreeflight Design Shop: http://www.freeflightdesign.comDrop by! ___x_x_(")_x_x___

[chrisal 9]

Hi,If it helps, the relevant code is here:(A:Airspeed mach, mach)Definitely does not deliver the same result as in FS9Something is differentChris

[Gypsy Baron 10]

>Hi>>I'm happily using David Maltby's fine Comet 4 in FSX. All the>xml gauges but one work flawlessly.>However the Mach gauge reads high - not accurately as it does>in FS9.>I've tried other of DM's Mach gauges (e.g. his VC 10)but with>the same result.>>Is the mach speed output data different in FSX from FS9?>>Glad of any help>>Cheers>ChrisI've noticed this also, Chris, on the 1-11 or Trident. I think I've noticed it on other aircraft as well but I know I did look into Dave's code for the gauge and it appears correct and uses the very SAME variable to displaythe ToolTip Mach reading as it does to display the needle,and of course the two are NOT in agreement.This leads me to believe that there is conversion taking place "behind the scenes" in the ToolTip routine that causesthe error. I've not checked to see which item is correct...thegauge display of the tooltip readout or neither.Just one more little subtle point of diversion from FS9 to FSX. Paul

[Gypsy Baron 10]

>Without knowing what his gauges use to display (i.e. is it a>default FS mach value or not)... we wouldn't be able to say if>it's FSX or his gauge.Here are the two applicable statements from the Trident Machgauge.To drive the gauge needle he usues:(A:Airspeed mach, mach)To display the mach value he uses:Mach %((A:Airspeed mach, mach))%!1.3f!The same variable in both cases, but the results are not thesame for both. And yes, the non-linearity statements are correct and the gauge does, in fact, work OK in FS9. Paul

[chrisal 9]

>>Hi>>>>I'm happily using David Maltby's fine Comet 4 in FSX. All>the>>xml gauges but one work flawlessly.>>However the Mach gauge reads high - not accurately as it>does>>in FS9.>>I've tried other of DM's Mach gauges (e.g. his VC 10)but>with>>the same result.>>>>Is the mach speed output data different in FSX from FS9?>>>>Glad of any help>>>>Cheers>>Chris>>>I've noticed this also, Chris, on the 1-11 or Trident. >I think I've noticed it on other aircraft as well but I >know I did look into Dave's code for the gauge and it >appears correct and uses the very SAME variable to display>the ToolTip Mach reading as it does to display the needle,>and of course the two are NOT in agreement.>>This leads me to believe that there is conversion taking >place "behind the scenes" in the ToolTip routine that causes>the error. I've not checked to see which item is>correct...the>gauge display of the tooltip readout or neither.>>Just one more little subtle point of diversion from FS9 to>FSX.>> Paul>The gauge reading is definitely out (and high)-I've checked it carefully. I haven't checked tooltips but it looks like that is the correct reading.The mystery deepens...Chris

[taguilo 33]

Hi,Just a little test that can be made to ensure that it is definitely a "real" different interpretation in FSX vs FS9, and not a "unit" problem:Replace the unit "mach" or any other in both Avars used in and with "number", or even without unit -like (A:FSvar)-, and use a test gauge to test the values.If all readings coincide, then certainly it is a conversion issue, otherwise it must be a different interpretation...:-)Tom

[Gypsy Baron 10]

-SNIP->The gauge reading is definitely out (and high)-I've checked it>carefully. >I haven't checked tooltips but it looks like that is the>correct reading.>>The mystery deepens...>>ChrisI just finished a 2+ hour flight in the Trident.At FL 240, my IAS was 326 kts, the mach gauge read 0.8while the tooltips mach was 0.74.At that ALT and around the 300-330 IAS range it seemed thatthe gauge read about 0.05 to 0.06 mach higher than the tooltipsreported.As I was on approach, I noticed the mach gauge reading up around0.4 or more while tooltips reported 0.27 or so. My IAS was probably about 180 - 200 kts and I was at 2800 feet.Definately something amiss in FSX with regards to this. I can'timaginer why the very same variable would cause the gauge needleto be offset on the high side and not be a fixed offset throughoutthe range. Some sort of wierd scaling issue at hand it seems. Paul

[tgibson 11]

The VSI gauge I was talking about had fractional non-linearity values as well, until I fixed it. Try multiplying the variable by 100 along with the min/max and non-linearity values.Might be the difference between FS9 and FSX???Hope this helps,--Tom GibsonCal Classic Propliner Page: http://www.calclassic.comFreeflight Design Shop: http://www.freeflightdesign.comDrop by! ___x_x_(")_x_x___

[Gypsy Baron 10]

>Hi,>>Just a little test that can be made to ensure that it is>definitely a "real" different interpretation in FSX vs FS9,>and not a "unit" problem:>>Replace the unit "mach" or any other in both Avars used in> and with "number", or even without unit>-like (A:FSvar)-, and use a test gauge to test>the values.>If all readings coincide, then certainly it is a conversion>issue, otherwise it must be a different interpretation...:-)>>Tom>I changfed the units from mach to number yesterday Tom.The gauge and tooltip readings remained the same as before...in error...I also did some other tests that yielded some rather strangeresults.I placed the Trident at 24K, 320 KIAS on autopilot/autothrottleand noted the speed/mach readins.I then switched to the A321 using the ALT/menu bar/Select Aircraft.When the A321 loaded I was cruising at a MUCH higher speed andwas getting the overspeed warning. When the autothrottle broughtthe speed back to 320 KIAS I then re-selcted the Trident.When the Trident loaded it was showing about 230 or 250 KIAS...I tried swapping the 747-800 in and out as well and was gettingthe same sort of speed disparity between aircraft types.I really can't imagine what could be causing this sort of behavior.I'm going to dig around in my various gauge folders and see if I can find another MAch gauge with tooltips and test it in FSX. Paul