7/13/2023 0 Comments Density altitude formulaBTW, my background is electrical engineering. You might help us about adiabatic expansion. Good to know that we have someone here with degree of Physics, very interesting. Rctech was taken when I signed up but since I started in RC on year 2007 I used 2k7, where ''k'' is derived from a technical prefix kilo. Here's the formula for Thrust from so we can solve it again.īTW, rctech2k7 is a short for RCTech2007. So even the engine is on a test stand it has airspeed when it's running. BTW, I've got mistake here, I should consider intake airflow because in reality air accelerates around the turbine and becomes free stream. It also eliminate other variable including constant. To be practical I just used value on the output side of an engine and get comparison between the test result. I agree, it’s really complicated to determine parameters of an engine, because it takes time and some guts to analyze thermodynamics process. Velocity is in a second degree so if we try to look at how the velocity change with respect to the change of thrust, the result is smaller. The rate that the thrust change with respect to air density is constant while expo to velocity but velocity doesn't have a factor of density if I'm not mistaken. If we look at how the thrust is affected by the following parameters then we can make an assumption: Our turbine is being controlled by temperature and RPM so at maximum fuel supply I believe this exhaust velocity is being limited by these control parameters. Although efficiency and nozzle design are also the major factor that affects exhaust velocity, they are constant for an existing engine. If we analyze the formula for Ve, the only variable is the Temperature. Yeah, it looks scary on a few glance and also becoming into engineering due to design aspect. The equations are not that difficult to build they just look scarry. I am in no way being a Jerk just trying to give you an anwser. So I guess to try and anwser the origional question is - How much time do you want to spend to get an exact anwser. All conditions ''variables'' have to be tested twice and with one or two controlled conditions in order to collect the accurate data set needed. It would be great if someone had the time to do it, but realistically with about 30 engine designs in the market place today this could be a full time job that could take a year or so. But again it is only accurate for a specific engine design. What would need to be done is all parameters and DATA SETS need to be put into an Excel spreadsheet and write the program to have a quick logmarithic means for formulation. Tim, maybe you are referring to this one:
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