Jump to content

Archived

This topic is now archived and is closed to further replies.

Recommended Posts

Having the NGX at FL370 , I decided to close both bleed valves to simulate cabin pressure loss. I was expecting a very quick drop in pressure, and was suprised to see pressure loss was minimal. Opening the outflow valve manually to 100%, increased the rate of pressure loss. Just wondering, does anyone know that this is the way the real aircraft would respond.---This is my first post (hope it got to the correct area !). T/Y

Share this post


Link to post
Share on other sites
Having the NGX at FL370 , I decided to close both bleed valves to simulate cabin pressure loss. I was expecting a very quick drop in pressure, and was suprised to see pressure loss was minimal. Opening the outflow valve manually to 100%, increased the rate of pressure loss. Just wondering, does anyone know that this is the way the real aircraft would respond.---This is my first post (hope it got to the correct area !). T/Y
You answered your own question there! The outflow valves do just that, release pressure from the pressure hull. If they're closed, pressure will remain constant. The packs simply pressurize.By the way, there's an NGX forum. http://forum.avsim.n...32-pmdg-737ngx/

___________________________________________________________________________________

Zachary Waddell -- Caravan Driver --

Facebook: http://www.facebook.com/zwaddell

Avsim ToS

Avsim Screenshot Rules

Share this post


Link to post
Share on other sites

Thanks for the reply Zach. I realized that the outflow valve would definitely increase the rate of depressurization of the cabin when opened to 100%. What I was curious about is whether the rate of pressure loss in the cabin would be very slow. During the sim test I performed (both bleeds closed), the loss of pressue took several minutes. Though I have been studying the 737 for about 10 years, I was always under the assumption that at high altitudes, the loss of an engine would very quickly 'drop the masks' in the cabin. Kinda suprised me. However, I guess with the large volume of cabin air, compared to the small outflow valve, this is probably correct. (and besides, the NGX is PMDG-has to be correct !!!)

Share this post


Link to post
Share on other sites
However, I guess with the large volume of cabin air, compared to the small outflow valve, this is probably correct.
Exactly!As for the rest, I'm thinking that you may not fundamentally understand the pressurization process. If you do, I apologize. Here's a basic simplified run down. Pressurization begins on the ground (typically) with the outflow valves completely closed. The outflow valves open after a certain pressure differential is reached between outside pressure and cabin pressure (during the aircraft's climb to cruise). At that point the aircraft is opening the outflow valves to achieve a particular "climb rate" within the cabin (pressure is decreased slowly) until the desired cabin altitude is reached.

___________________________________________________________________________________

Zachary Waddell -- Caravan Driver --

Facebook: http://www.facebook.com/zwaddell

Avsim ToS

Avsim Screenshot Rules

Share this post


Link to post
Share on other sites

  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
  • Donation Goals

    AVSIM's 2020 Fundraising Goal

    Donate to our annual general fundraising goal. This donation keeps our doors open and providing you service 24 x 7 x 365. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. We reset this goal every new year for the following year's goal.


    43%
    $10,910.00 of $25,000.00 Donate Now
×
×
  • Create New...