Tim_Fragmagnet Posted December 19, 2022 Posted December 19, 2022 (edited) I'll make it short and sweet before getting to the dataposting. The huey has a transmission power limit of 1158shaft horsepower, HOWEVER, the engine itself, while being capable of 1400shp, is actually limited to an N1% RPM of 101.8%, which is over 1300, not 1158, not 1100. In the DCS huey, the N1 limit for the engine is supposed to be higher than it is, but as implemented in DCS, it is 1158shp. At 100% N1 RPM the aircraft is producing 1158shp, instead of the correct higher value, this means that you are at 50psi of torque at 100% N1 RPM. The correct setup would be to have the aircraft produce 50psi of torque at 98% N1 RPM instead of 100%. Why is this relevant? This is relevant because at 98% N1 RPM on the real huey, you are only generating around 580C of EGT. That's right, at 1158shp, your transmission limit, you shouldn't even be close to overheating the engine. (At sea level, flight parameters change as your density altitude increases) As the huey is currently modeled, 98% N1 RPM actually produces about 590C, but it is also only producing about 990-1000shp. As we go up in N1 to reach 1158shp we rapidly gain EGT to the point where in quite a few flight profiles, we are overheating the engine, where we realistically shouldn't be, meaning we need to lower our power output to prevent the overheating when we shouldn't need to. As for the data 0 I also took the liberty of graphing the same data from the DCS huey and overlaying the different sets of data. As you can see by the horsepower graph, it very clearly does not line up with 5 other UH-1H engines that very clearly stay near each other minus a few stray datapoints. If we simply project our DCS data onto the real data plot and line them up, and assume the engine does just have a linear power curve all the way to 100% N1, we would reach 1333SHP. And if we consult null We can see that out of 12162.1 minutes of flight, this UH-1H spent 20 seconds at 1300shp. So the engine can in fact reach 1300shp while mounted in a huey. So 1333 doesn't seem like an unreasonable limit. The EGT comparison is also interesting, showing an underproduction of EGT at low N1 settings but an OVER production of EGT at high N1 settings. And before you question this and say "well maybe it's just modeled as an old engine". First, there is an engine resource slider, effectively an engine age/health slider already built into the game to simulate this so it shouldn't be modeled as having reduced power to begin with. Second. Taken from null Here is a graph comparing 2 sets of EGT data One set showing a new engine with only 16hours of operation before the data collection Another showing that same engine after 1939.1 hours of operation, the engine failed less than 10 hours later. Now here it is overlaid with our DCS EGT data There are plenty of other issues with the module, I would like to see this one (two?) fixed however. Our engine model has 1158shp as 100% N1 but is using an EGT curve similar to one with a higher 100% N1 limit, meaning we are getting less power for the same EGT output. 100% N1 Should be producing more power than it currently is. Some data says 1200shp at 100%, other data says 1330shp+ at 100%. Pre-production huey data states 100% N1 to be 1340shp. The EGT curve could use a little tweaking as well. Edited February 23, 2023 by Tim_Fragmagnet 8 1
Tim_Fragmagnet Posted February 23, 2023 Author Posted February 23, 2023 (edited) Further research has produced an answer. Performance data of the YUH-1H, the pre-production model of the UH-1H, the one every future UH-1H would be based off of. Page 44 1340shp Whether that means 1340shp at 100% N1 or 101.8% N1 (the limit of the engine) Well page 205 has the answer to that question. At least for the early UH-1Hs 100% N1 is 1340shp. I will update the OP with this information. Edited February 23, 2023 by Tim_Fragmagnet 1 1
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