xrx Posted October 24, 2023 Posted October 24, 2023 (edited) f15c used to have fuel flow rate around 12k per engine at 60k alt, at Match2.0. same clean config lower fuel to match total load of F15C, the F15E cant even get to Mach 2.0. - can you post fuel rate curves F15C and F15E at different altitudes 40k 50 55 60, and the TAS speeds - F15c used to be possible to cross Tbilisi to Anapa at Mach2, F15e cant get even half way to Sochi without running out of fuel. Please check! Thank you Edited October 24, 2023 by xrx
Rainmaker Posted October 24, 2023 Posted October 24, 2023 (edited) 42 minutes ago, xrx said: f15c used to have fuel flow rate around 12k per engine at 60k alt, at Match2.0. same clean config lower fuel to match total load of F15C, the F15E cant even get to Mach 2.0. - can you post fuel rate curves F15C and F15E at different altitudes 40k 50 55 60, and the TAS speeds - F15c used to be possible to cross Tbilisi to Anapa at Mach2, F15e cant get even half way to Sochi without running out of fuel. Please check! Thank you C and E are two different airplanes for one. E and C are two completely different modules in terms of engine modeling for two. C and E are replicating two different engine types for three. The C is done by ED, you are more than welcome to do your own fuel flow test and curves for that one. Based on just those comparisons...as far as I need to go. Edited October 24, 2023 by Rainmaker 4
xrx Posted October 24, 2023 Author Posted October 24, 2023 34 minutes ago, Rainmaker said: C and E are two different airplanes for one. E and C are two completely different modules in terms of engine modeling for two. C and E are replicating two different engine types for three. The C is done by ED, you are more than welcome to do your own fuel flow test and curves for that one. Based on just those comparisons...as far as I need to go. hold a sec C and E is same airplane from aerodynamics point of view, it does have the same frame (exclude minor variations second seat etc) - length/height, wingspan, wing area, wing airfoil model -- according to wiki specs its exactly apples to apples - engines are dual pratt whitneys f100pw220s exactly same 65 kN dry thrust (newer pw229 has 80kN) https://en.wikipedia.org/wiki/McDonnell_Douglas_F-15_Eagle https://en.wikipedia.org/wiki/McDonnell_Douglas_F-15E_Strike_Eagle only difference is internal fuel tanks, which built for different tasking - but clean config is exactly same again - at same clean config and total weight it has to fly C and E exactly same, it terms of acceleration, top speed, alt limit - it would be interesting to show community reference curves how f15c f15e different airpseed/altitude/aoa/input sensitivities, etc Thank you
Rainmaker Posted October 24, 2023 Posted October 24, 2023 (edited) 8 minutes ago, xrx said: hold a sec C and E is same airplane from aerodynamics point of view, it does have the same frame (exclude minor variations second seat etc) - length/height, wingspan, wing area, wing airfoil model -- according to wiki specs its exactly apples to apples - engines are dual pratt whitneys f100pw220s exactly same 65 kN dry thrust (newer pw229 has 80kN) https://en.wikipedia.org/wiki/McDonnell_Douglas_F-15_Eagle https://en.wikipedia.org/wiki/McDonnell_Douglas_F-15E_Strike_Eagle only difference is internal fuel tanks, which built for different tasking - but clean config is exactly same again - at same clean config and total weight it has to fly C and E exactly same, it terms of acceleration, top speed, alt limit - it would be interesting to show community reference curves how f15c f15e different airpseed/altitude/aoa/input sensitivities, etc Thank you 1000% false. All of it. You have over 20 units of additional drag and a different engine that consumes more gas. And comparing it to the C that has a very simple engine model is not the way to prove your point here. Wikipedia isn't either. Comparison to something quantifiable in real life would be...which is where the numbers came from. Again, there are no issues there. Edited October 24, 2023 by Rainmaker 4
Rainmaker Posted October 24, 2023 Posted October 24, 2023 1 minute ago, xrx said: could you point out public aerodynamics ref tables that you modeling F15E against, raw tables or analytical curves, would be more valuable to believe so NASA is full of them. Search their site. 3
draconus Posted October 25, 2023 Posted October 25, 2023 On 10/24/2023 at 4:29 AM, xrx said: only difference is internal fuel tanks, which built for different tasking - but clean config is exactly same But we don't have the same clean config in DCS as F-15C - our modeled F-15E has non-removable CFTs - with huge drag penalty. You can barely touch M2.0 with these on. You're new here so bear in mind that in order to make devs change something you better provide some hard facts as IRL docs (better in PM to make sure you're not breaking forum rule 1.16 https://forum.dcs.world/guidelines/ ). You don't seem to be knowledgable enough to keep discussing this subject. And, no, they don't provide their docs to prove you wrong. 4 Win10 i7-10700KF 32GB RTX4070S Quest 3 T16000M VPC CDT-VMAX TFRP FC3 F-14A/B F-15E CA SC NTTR PG Syria
xrx Posted October 26, 2023 Author Posted October 26, 2023 f15c @55k 1000tas runs fuel 15k pph (per nosle) f15e @55k 1000tas runs fuel 26k pph please check pics attached bellow f15e ff.bmpf15c ff.bmp
Rainmaker Posted October 26, 2023 Posted October 26, 2023 You are not even close to understanding how to measure this correctly. 3
xrx Posted October 26, 2023 Author Posted October 26, 2023 (edited) f15c f15e side by side both weigh 43k lb (f15e less fuel to match), @alt 55k 1000kn tas both get same airflow, both around 3deg aoa, both run same pratt whitney turbofans. 15k vs 26k is almost twice the difference, wouldnt bother was it close. to what ff pph means is there anything more to measure correctly? attaching trk file test air speed ff.miz Edited October 26, 2023 by xrx
draconus Posted October 26, 2023 Posted October 26, 2023 3 hours ago, xrx said: both run same pratt whitney turbofans. They are far from the same and I like how you omitted drag, just for convenience 5 Win10 i7-10700KF 32GB RTX4070S Quest 3 T16000M VPC CDT-VMAX TFRP FC3 F-14A/B F-15E CA SC NTTR PG Syria
xrx Posted October 26, 2023 Author Posted October 26, 2023 (edited) i dont understad both f15c and f15e same pw220 engines (didnt intend to omit anything), build under same roof what drag you talking about? fuel flow twice the difference whers that coming from? only thing is which of ED or RAZMAM model more superior, f15c ED model wasnt updated since inception (about 10y ) tells thats pretty good reference.. Edited October 26, 2023 by xrx
razo+r Posted October 26, 2023 Posted October 26, 2023 26 minutes ago, xrx said: i dont understad both f15c and f15e same pw220 engines (didnt intend to omit anything), build under same roof what drag you talking about? fuel flow twice the difference whers that coming from? only thing is which of ED or RAZMAM model more superior, f15c ED model wasnt updated since inception (about 10y ) tells thats pretty good reference.. The E in DCS has the 229, not 220. Additionally, the E has CFTs that provide additional drag compared to the C without CFTs- 2 2
draconus Posted October 26, 2023 Posted October 26, 2023 31 minutes ago, xrx said: f15c ED model wasnt updated since inception (about 10y ) tells thats pretty good reference.. You're wrong - it was corrected and fixed many times and is still waiting for minor fixes. It's differen't aircraft - get it over with - and as said - not modeled to the same degree of fidelity but flight model is still very good. 4 Win10 i7-10700KF 32GB RTX4070S Quest 3 T16000M VPC CDT-VMAX TFRP FC3 F-14A/B F-15E CA SC NTTR PG Syria
jaylw314 Posted October 26, 2023 Posted October 26, 2023 Don't forget the different canopies between the Charlie and Strike Eagle, too 3
xrx Posted October 28, 2023 Author Posted October 28, 2023 (edited) find it hard to believe side CFTs cause pph fuel rate nearly double at M1.5 compared to F15c (original ED modeling) it adds frontal cross section very minor relatively to the rest of the frame since you dont provide any public ref tables/nor your own, it could be any point in the air Edited October 28, 2023 by xrx
draconus Posted October 29, 2023 Posted October 29, 2023 It's called drag index. Have a read here: 2 Win10 i7-10700KF 32GB RTX4070S Quest 3 T16000M VPC CDT-VMAX TFRP FC3 F-14A/B F-15E CA SC NTTR PG Syria
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