N1 or N2 to manage the throttle-axis

[phjvh 0]

Hi,Busy now trying to "develop" a thrustmode and limiter in my panel.Question:Using total weight, temperature and altitude as some parameters i want to maintain a given N1 to steer the throttle-axis.But that works not very accurately.Tried EPR too.Can someone tell me is N2 better?Or is there another method?Jan"Procul Negotiis"

[Guest Ron Freimuth]

>Hi,>>Busy now trying to "develop" a thrustmode and limiter in my>panel.>Question:>Using total weight, temperature and altitude as some>parameters i want to maintain a given N1 to steer the>throttle-axis.>But that works not very accurately.>Tried EPR too.>Can someone tell me is N2 better?>Or is there another method?>>Jan Try setting the throttle to change THRUST. Which is available in XML and token variables. A Thurst of 0.05 Weight will just keep an AC moving. Ron

[phjvh 0]

Ron,Thanks.I use, don't mind the synthax: (A:TURB ENG1 CORRECTED N1) (Eng1 N1 wanted) > if{ DECREASE thottle axis }(A:TURB ENG1 CORRECTED N1) (Eng1 N1 wanted) < if{ INCREASE thottle axis }And it works.Is it better to read (A:TURB ENG1 JET THRUST) in pounds and try to balance that value with the throttle axis command?What to do with the N1 (EPR and) settings; i assume there is a connection between Thrust, N1 (and EPR).Jan"Procul Negotiis"

[Guest _ak]

better is read tables 1502, 1503 and 1504 from air fileOn avhistory.org forum I seen equotions for predicting N1 from throttle position. It can be used for opposite task too.

[Guest Ron Freimuth]

>Ron,>>Thanks.>I use, don't mind the synthax: >(A:TURB ENG1 CORRECTED N1) (Eng1 N1 wanted) > if{ DECREASE>thottle axis }>(A:TURB ENG1 CORRECTED N1) (Eng1 N1 wanted) < if{ INCREASE>thottle axis }>And it works. N1 and Corrected N1 are the same at 15 C. >Is it better to read (A:TURB ENG1 JET THRUST) in pounds and>try to balance that value with the throttle axis command? At least if one uses THRUST he doesn't depend on a variety of AIR file turbine tables. Though, how fast THRUST changes relative to the THROTTLE depends on the tables. Further, total Thrust is the sum of all the engines. At least one can calculate the thrust required to just keep an AC moving. From the "0.05 * Weight" I gave. However, it takes more thrust to start the AC. One may have to change the 'gain' to the throttle to keep the taxi speed control stable. There is also a delay due to the spool rated.>What to do with the N1 (EPR and) settings; i assume there is>a connection between Thrust, N1 (and EPR).>Jan Don't use MSFS EPR, it is very inaccurate. Though, may be adjusted in the AIR file to at least give the correct TO EPR. Ron

[phjvh 0]

Hi,After some tweaking and testing on different altitudes with varying weights etc. it seems my plane can hold a given N1 pretty good.Question: should i use N1 or Corrected N1 (in use) in the algorithms?How or should i compensate for temperature and density.Btw. reading and comparing Total Weight and Thrust shows interesting correlations with N1.Next step, how to steer the elevator trim to prevent exceeding maximum speeds.How can i read airfiles in xml? i use Herve Sors AFSD 210.Thanks for the comments and advices, please more!Jan"Procul Negotiis"