cabin pressure

[vololiberista 205]

I recently came across this cabin height gauge Initially its starting value was 10,000ft rising to the same altitude as the aircraft during the climb.now it starts at airfield height but still continues to actual aircraft altitude.I'd like to do some mods but am not sure what to do.1. I'd like to be able to set an upper limit say 10,000ft being the actual cabin pressure compared to the outside2. To set a rate of increase/decrease in pressurisation- Also to ensure that the gauge reads correctly on landing.3. A cabin pressure dump equalising the cabin pressure to the outside

<Gauge Name="Cabin Height" Version="1.0">   <Image Name="Cabin_height_bg.bmp" ImageSizes="195,195,195,195" Luminous="1"/>   <Element>	  <Position X="98" Y="98"/>	  <Image Name="Cabin_Needle.bmp" PointsTo="East" ImageSizes="120,22,120,22" Luminous="1">		 <Axis X="31" Y="11"/>	  </Image>	  <Rotate>		<Value>(A:Indicated Altitude,feet) 1000 /</Value>		 <Failures>			<SYSTEM_ELECTRICAL_PANELS Action="0"/>		 </Failures>		 <Nonlinearity>			<Item Value="0" X="63" Y="160"/>			<Item Value="5" X="26" Y="109"/>			<Item Value="10" X="39" Y="48"/>			<Item Value="15" X="97" Y="22"/>			<Item Value="20" X="159" Y="49"/>			<Item Value="25" X="174" Y="112"/>			<Item Value="30" X="137" Y="159"/>		 </Nonlinearity>		 <Delay DegreesPerSecond="6"/>	  </Rotate>   </Element>   <Mouse>	  <Tooltip>Cabin Height</Tooltip>   </Mouse></Gauge>

[mgh 89]

It seems to me that the gauge is simply an altimeter displaying in thousands of feet. - <Value> (A:Indicated Altitude,feet)1000 / </Value>Unless you want to model a complete cabin pressuriation system, the simlpest solution is to make the output follow altitude until some critical value (typically 6000-8000 ft) and then remain constant thereafter at the critical value.

[vololiberista 205]

It seems to me that the gauge is simply an altimeter displaying in thousands of feet. - <Value> (A:Indicated Altitude,feet)1000 / </Value>Unless you want to model a complete cabin pressuriation system, the simlpest solution is to make the output follow altitude until some critical value (typically 6000-8000 ft) and then remain constant thereafter at the critical value.

Yes, that's what i want to try to do.vololiberista

[mgh 89]

Yes, that's what i want to try to do.vololiberista

Replace the <Value>(A:Indicated Altitude,feet) 1000 /</Value> line with: <Value> (A:Indicated Altitude,feet)1000 / 8 > if{8} els{(A:Indicated Altitude,feet)1000 /}</Value>This should limit it to 8(000) ft.My XML's a bit rusty and I haven't tried it.

[vololiberista 205]

Replace the <Value>(A:Indicated Altitude,feet) 1000 /</Value> line with: <Value> (A:Indicated Altitude,feet)1000 / 8 > if{8} els{(A:Indicated Altitude,feet)1000 /}</Value>This should limit it to 8(000) ft.My XML's a bit rusty and I haven't tried it.

Thanks I'll try that.vololiberista

[vololiberista 205]

Replace the <Value>(A:Indicated Altitude,feet) 1000 /</Value> line with: <Value> (A:Indicated Altitude,feet)1000 / 8 > if{8} els{(A:Indicated Altitude,feet)1000 /}</Value>This should limit it to 8(000) ft.My XML's a bit rusty and I haven't tried it.

Sorry to say that didn't work :( The gauge stayed at zero the whole time.

[phjvh 0]

Hi,There are missing some spaces.Try:<Value>(A:Indicated Altitude,feet) 1000 / 8 > if{ (8) } els{ (A:Indicated Altitude,feet) 1000 / }</Value>Hope it helps,Jan

[vololiberista 205]

Hi,There are missing some spaces.Try:<Value>(A:Indicated Altitude,feet) 1000 / 8 > if{ (8) } els{ (A:Indicated Altitude,feet) 1000 / }</Value>Hope it helps,Jan

Thanks that was better but as the a/c climbed above 8,000ft the needle went back to zero. When descending to 7,500ft the needle went back up from zero to 8 as the a/c passed FL80!!

[phjvh 0]

Hi,Tested this one, works ok.<Element><Position X="63" Y="64"/><Select><Value>@power</Value><Case Value="0"><Image Name="altimeter needle.bmp" PointsTo="North"><Axis X="8" Y="47"/></Image></Case><Case Value="1"><Image Name="altimeter needle.bmp" PointsTo="North"><Axis X="8" Y="47"/></Image></Case><Case Value="2"><Image Name="altimeter needle.bmp" PointsTo="North"><Axis X="8" Y="47"/></Image></Case><Case Value="3"><Image Name="altimeter needle bright.bmp" Bright="Yes" PointsTo="North"><Axis X="8" Y="47"/></Image></Case></Select><Rotate><Value Minimum="0" Maximum="8">(A:Indicated Altitude,feet) 1000 / 8 > if{ 8 (>L:Indicated Altitude,feet) } els{ (A:Indicated Altitude,feet) 1000 / (>L:Indicated Altitude,feet) } (L:Indicated Altitude,feet) </Value><Nonlinearity><Item Value="0" X="63" Y= "0"/><Item Value="1" X="86" Y= "31"/><Item Value="5" X="63" Y="104"/><Item Value="8" X="24" Y= "50"/></Nonlinearity><Delay DegreesPerSecond="90"/></Rotate></Element>So yoy can take out, what you need.Hope it works ok now,Jan

[vololiberista 205]

Hi,Tested this one, works ok.<Element><Position X="63" Y="64"/><Select><Value>@power</Value><Case Value="0"><Image Name="altimeter needle.bmp" PointsTo="North"><Axis X="8" Y="47"/></Image></Case><Case Value="1"><Image Name="altimeter needle.bmp" PointsTo="North"><Axis X="8" Y="47"/></Image></Case><Case Value="2"><Image Name="altimeter needle.bmp" PointsTo="North"><Axis X="8" Y="47"/></Image></Case><Case Value="3"><Image Name="altimeter needle bright.bmp" Bright="Yes" PointsTo="North"><Axis X="8" Y="47"/></Image></Case></Select><Rotate><Value Minimum="0" Maximum="8">(A:Indicated Altitude,feet) 1000 / 8 > if{ 8 (>L:Indicated Altitude,feet) } els{ (A:Indicated Altitude,feet) 1000 / (>L:Indicated Altitude,feet) } (L:Indicated Altitude,feet) </Value><Nonlinearity><Item Value="0" X="63" Y= "0"/><Item Value="1" X="86" Y= "31"/><Item Value="5" X="63" Y="104"/><Item Value="8" X="24" Y= "50"/></Nonlinearity><Delay DegreesPerSecond="90"/></Rotate></Element>So yoy can take out, what you need.Hope it works ok now,Jan

many thanksvololiberista

[vololiberista 205]

:( That works fine. Many thanks. Your code should go into an archive!!!!vololiberista

[spokes2112 179]

Just another take on the deal.... maybe give this a try.. <Value>(A:Indicated Altitude,feet) 1000 / 8 min</Value>Take the minimum of either 8 or the division of alt by 1000.. The maximum = 8Roman

[vololiberista 205]

I came across -this web page- with regard to cabin pressure.What are your thoughts?vololiberista

[n4gix 4,947]

I came across -this web page- with regard to cabin pressure.What are your thoughts?vololiberista

My thoughts are that William graciously posted working XML script(s) for the three gauges, and even included his artwork......take it and run! :)

[vololiberista 205]

My thoughts are that William graciously posted working XML script(s) for the three gauges, and even included his artwork......take it an run! :)

The only thing is that his pressure differential calculation rises too quickly. It get to 7.8 at about 29000feet. So i will have to slow it down a bit.But certainly it's good stuff to work with.vololiberista