zerO_crash Posted April 20, 2020 Posted April 20, 2020 (edited) This has really bothered me some time now. Having conferred with a couple pilots of Mi8, I generally got their opinions on how they fly the real MI8s and MI17s. Now, what I notice from their descriptions of actual flying of these helicopters is the PTIT temperatures they mention. They do not reflect the temperatures that are in accordance to the MI8 in DCS or it´s manual. I pulled up some docs that are widely available on MI8s and Mi17s, keeping in mind that I am looking for the models with the specific engine we have in our MI8MTV2, namely the Izotov TV3-117VM! Having compared the engine limitations graphs, I cannot help but wonder why we are so much handicapped on the PTIT in DCS? I will add two pictures, one is from the DCS manual and the other one is from a real Mi17 manual, which I can provide on request. It occurs to me that although similar in performance, somehow our MI8 is is handicapped to the point where at cruise flight, to be able to stay within the limits of the engine, you cannot pull above 10 angle of attack on the collective otherwise you run it too hot for unlimited cruise mode. That`s 10 out of 15 AOA. Not that this should be a comparison, but it is pretty crazy, you pass the temperature limits in no time. Take a look at for example cruise 1 in the pictures. While the real life PTIT temperature is permitted 910*C (later in the manual it`s stated as unlimited duration), our DCS manual states for "Max LTD Cruise" 855*C (taking the highest value here with PSS). That is 55*C difference between the real engines and our, making it sometimes impossible to follow the real flight instructions where pilots claim that they fly unlimited cruise duration at 860 to 870 PTIT. Also, while we are at this, another instrument that I guess should be relevant for propper real life engine operation would be the EPI (engine pressure ratio). You will never reach even the "K" pressure index before the PTIT limits you. And although this is confirmed by multiple pilots of the MI8/17 I´ve talked with, one being an active member here in DCS community and on the forums, I still wonder then why this gauge is here at all, when it will absolutely never be the limiting factor in the MI8, unlike Ka50 which is flown solely by EPR and PTIT. Edited April 20, 2020 by zerO_crash [sIGPIC][/sIGPIC]
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