Hello,Seeing this inspired me. I decided to create a table giving me torque settings, based on simple maths: (Maxmimum Torque Setting Used - Minimum Torque Setting Used) / No. of Temperature Increments = Diference Between Each Torque Setting.Those of you good with maths will see at lest one flaw with that forumla, but the precision is good enough for Flight Simulator. The program outputs 80 Torque settings: one for each degree between 40 and -40; the J41's outermost temperature operating limits.There currently are some limitations, however:

• It can only calculate the torque settings for pressure altitudes between 0 and 1000ft
• It assumes the Torque/Temperature difference to be linear.

The former problem could be sorted by a fellow programmer quite easily, I however, do not see myself developing this further.For Pilots:Here is the table with the torque settings:http://www.easy-share.com/1910514884/Jetstream 41 - Torque Settings.htm://http://www.easy-share.com/191051488...ue Settings.htmScreenshot:For Developers: Source:http://www.easy-share.com/1910514699/j41tt.rarFor what it's worth, I'm releasing this under the GPL (included in the download), so feel free to do what you like with it.

I've tried to do a similar thing and posted results in the FS2Crew forum here: http://forums1.avsim.net/index.php?showtopic=286655This boils down to a question of what is you're primary variable in determining EGT? There is strong logic for either or both density altitude and ambient temperature (beyond it's effect on density altitude).Heat transfer (and thereby cooling of an engine) is largely dependent on two factors. 1. The first is the mass of the two bodies between which heat is moving. This is a simple follow up property from heat being stored within molecular and intermolecular bonds--the more of them there are (i.e. more mass), the more heat something can hold. Moving to the real world, if you think about boiling 1L of water or 10L of water, I think most people readily recognize that it takes more engergy to boil the 10L because of it's great mass--that's why units of specific heat capacities are J/K/g (see the mass showing up there?).The mass of our first body, the engine, is fixed by it's structure that makes it an engine. However the engine is cooled by the surrounding air. A less dense body of air by definition has a lower mass of air molecules and can hold less heat. Where does this lead? Well, that's basically what density altitude tells us. It is a meaures saying the density of the air currently around you is the same as air at a certain altitude under standard temperature and pressure. The higher the density altitude-->the thinner the air-->the less mass to transfer heat to.2. The second factor for heat transfer is the temperature difference between the two bodies. Electrical engineers will readily understand this in terms of voltage and current--the greater the potential difference (voltage), the greater the current. Less scientifically, if you think about trying to push 1,000 people in to a room, it will be readily apparent that people will enter this room faster if it were empty than if it already had 900 people.The temperature of the engine cylinder heads (generally the best approximation of the engine temperature as a whole) is actually fairly constant. However, colder air increases the temperature difference and again makes heat transfer easier. This is why a moving airstream also aids cooling, as it is constantly moving away the "old" air that has already been heated by the engine and refreshes it with new cooler air. However, it should be noted that airspeed is only a small part of the speed at which air passes over an engine, as the intakes are often behind the propellars which are pushing large amounts of air through the engine at high speed (can you make the connection now as to why EGT drops when you increase RPM?).So that was a lot of writing without a clear point. What this comes to is that if you have the ability to do a multivariate analysis to relate two variables to EGT (or torque as an equivelant), you will probably actually get a very good relationship. There will certainly be some other factors, but these are the two primary ones. The question is for those of us without fancy statistics software doing single variable regression is which one gives us a better relationship?My thought is that it's density altitude. Why? It's actually very simple. Temperatures in the real world vary from say -40C to +40C as you said....well in these heat transfer equations, units of K are used so that's a range of 233K to 313K...at most a 35% increase from the lowest value to highest. However, if you consider density atltiude, you can realistically see values from approximately -1,000' MSL (sea level airport and on -40C winter day) and 10,000' MSL (high altitude airport on a hot summer day). This variance equates to a >1,000% increase. Long story short, if we need to pick one as a constant, OAT is much closer to behaving as a constant than density altitude.Anyway, this was a lot of rambling. I'm glad to see effort being worked towards these data for the simulator. I doubt we'll ever have the several thousand dollar airine charts that account for runway length, aircraft weight, runway conditions, etc. However, being able to creat a ballpark figure we could use in the simulator certainly gets us the beter part of the way to the ultimate goal we all have.As a side note, in a static state these basic heat transfer equations are in fact linear. Heat transfer based on deltaT is actually an infinite summation series readily solved with integral calculus, however that assumes a dynamic state where one body cools and the other heats. However, the rapid passage of cool air over the engine allows a simplification to where neither body heats or cools and allows for this static state approximation through linear equations.Eric Szczesniak

Eric,Thank you very much for your explaination. I never thought I'd be applying the heat theories I learned in Physics in the real world :(.

Eric also used sensitivity analysis, a very practical and often used engineering tools. Pay attention to the attention getters and keep it simple (KISS)