Jump to content

Sign in to follow this  
markadeane

Engine startup modelling

Recommended Posts

I'm really pleased to see that the engine EGT rises smoothly now on startup, thanks guys! However I notice that the N1 spools up to a point in the mid teens then - as the starter toggle clicks back into the off position - very rapidly rises to the idle RPM. Is this how it actually happens? I honestly don't know so I'm curious to see if this is RW behaviour.Also the spool up and down (down more so) seems quite fast, especially for an engine with a fairly big N1 fan, 'rotational inertia/momentum' I think it's called, high school physics was a long time ago for me!Again, this might actually be realistic but I don't know. Can anyone with RW 747 experience comment?ThanksMarkPS: This is not meant to be a 'PMDG got it wrong' post. I simply don't have the experience to state categorically that it is incorrect, hence my appeal for expert comment!


Mark Adeane - NZWN
Boeing777_Banner_BetaTeam.jpg

Share this post


Link to post

I may be wrong, but as far as I understand, N1 refers to the large fan at the front of the engine, N2 and N3 (on the RR's) refer to the small compressor/turbines in the engine core. Therefore once the engine is turning, I would imagine this has a fairly rapid rise.


Alaister Kay

Share this post


Link to post

Don't know about the speed of power rise and fall but this might be an appropriate post to add this to.I have now noticed that fuel flow doesn't rise until the engine is stabilised. Don't think it's realistic. If this had to be done to increase reality I have no prob with it. It's just that my callouts don't work anymore : (Starter ON -> Rotation -> Oil pressure -> N1 -> (Fuel flow) -> Light up! -> Starter OFF -> Engine Stabilised)Xander


Xander Koote

All round aviation geek

1st Officer Boeing 777

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  
  • 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.


    2%
    $705.00 of $25,000.00 Donate Now
×
×
  • Create New...