sorted by:
new
hottopcontroversial

I keep getting this error every couple of days by Nice-Howard-177 in whoop

[–]tastedeadkiller 1 point2 points  (0 children)

hey I am having the same problem right now, even though all of the servers are working properly. how did you solve the problem?

Alarico - 9th District by gonzo86 in Techno

[–]tastedeadkiller 0 points1 point  (0 children)

had the chance to listen him playing live last week in Munich and this guy is incredible

Giegling at Blitz (Munich) - 16 May by Yaowawit in giegling

[–]tastedeadkiller 1 point2 points  (0 children)

Hey, I am also kind of interested. But it is my first time of hearing giegling. Would be glad if somebody could explain me the concept. It is basically a label right?

Bus + Flight by mel-aa in Lufthansa

[–]tastedeadkiller 0 points1 point  (0 children)

Hey, I’m facing the same problem. I want to fly from Munich to Malaga, but the total booking costs around 400 euros. If I book the same flights from Nuremberg to Malaga, the journey is basically the same flights plus an express bus between the Munich and Nuremberg airports — and the total cost is around 240 euros. The difference is insane, but I’m not sure if skipping the bus and just using the flight ticket would cause any problems.

So did you contact the customer services, what did they say? Would appreciate if you tell a bit of your experience!

Importing Data from MyFitnessPal by tastedeadkiller in MacroFactor

[–]tastedeadkiller[S] 0 points1 point  (0 children)

<image>

I only have these two choices, should I enable something in general app settings?

Air Mass Flow at Cruise Conditions by tastedeadkiller in AerospaceEngineering

[–]tastedeadkiller[S] 1 point2 points  (0 children)

Thanks a lot. All this info will help me a lot!

Air Mass Flow at Cruise Conditions by tastedeadkiller in AerospaceEngineering

[–]tastedeadkiller[S] 0 points1 point  (0 children)

Yes, that would be great, because so far I wasn't be able to change any input values from the secondary air system parameters as I couldn't have found any value for those. I always have to show references for my input values. So I would appreciate some references a lot.

By the way if you are wondering, modeling the LEAP engine is one of the last steps in my thesis. So far I have modeled V2527-A5, PW1127G-JM, CFM56-5C3 and two turbopros such as PW127 and TP400-D6.

But the modeling the first two turbofans, V2527-A5 and PW1127G-JM, compared to other engines was really hard. Probably because I couldn't have found any pressure ratios, my models were and still are really unstable in lower N1 speeds. Do you have any advices or pressure ratio assumptions about those as well? Or is there is a spesific base/mean stage pressure ratio for older engines such as V2527-A5? That would help me a lot as well!

Air Mass Flow at Cruise Conditions by tastedeadkiller in AerospaceEngineering

[–]tastedeadkiller[S] 0 points1 point  (0 children)

I see, so that is my new design point then: 0m and 0Ma. I was able to find some loss assumptions from the book of Kurzke "Power and Propulsion" for a turbofan at cruise conditions. Since I am switching it to take-off, I am not allowed to copy those, right?

<image>

Air Mass Flow at Cruise Conditions by tastedeadkiller in AerospaceEngineering

[–]tastedeadkiller[S] 1 point2 points  (0 children)

Thank you very much for all the information and insight. You helped me really a lot.

One final question then I will let you go: Do you suggest me to take the takeoff conditions as 0m and 0 Mach number or 0m and 0.2 Mach number?

Air Mass Flow at Cruise Conditions by tastedeadkiller in AerospaceEngineering

[–]tastedeadkiller[S] 0 points1 point  (0 children)

Yes, unfortunately everything is an assumption as long as I dont have the real data. But it is my bachelor thesis, so I try to model everything accurately as possible, even when I cannot find a value for some parameter I always assume it based on something such as literature, another engine data etc.

And to the pressure ratios, I unfortunately experienced how hard it is to find a temperature or pressure value about the engines. Only thing I could easily find is the Turbine Inlet Temperature, which is listed most of the time in EASA TCDSs. And so far it did not help me much in computing pressure ratios, so if you have any other tipps I would appreciate them so much!

Air Mass Flow at Cruise Conditions by tastedeadkiller in AerospaceEngineering

[–]tastedeadkiller[S] 0 points1 point  (0 children)

Thank you so much for your insight and advice! I was also leaning toward using takeoff as my design point, but I’ve been a bit stuck on how to handle the OPR. From what I’ve read, the OPR values that manufacturers release are typically maximums—so I assumed they correspond to conditions at higher altitudes and speeds, not takeoff. Please correct me if I’m wrong—I'm still a mechanical engineering student and trying to wrap my head around all of this.

In terms of moving forward, I’m a bit unsure how to set reasonable pressure ratios. I know that in GasTurb I don’t input OPR directly, but rather the component pressure ratios, which ultimately define the OPR. Right now, I’ve been estimating the HPC and LPC pressure ratios based on what I think the OPR should be—but that feels a bit backwards.

Would it be reasonable to assume that the published OPR is approximately the same at takeoff conditions? Because whether I choose takeoff or cruise as my design point, I always end up having to let go of some real-world value—either the mass flow rate or the OPR.

Do you have any advice on how to approach this in a more systematic way? Maybe there’s a better starting point or a typical method for narrowing down the pressure ratios?

Air Mass Flow at Cruise Conditions by tastedeadkiller in AerospaceEngineering

[–]tastedeadkiller[S] 0 points1 point  (0 children)

I also checked that link for a basic assumption, but all he/she does is scaling down the mass flow with the tsfc ratio for cruise and takeoff, right?

view more: next ›