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Post by jsaus on Apr 23, 2024 17:40:46 GMT -5
Also to note, even at FL230, I couldn’t maintain the MP required. Something is definitely wrong. FL230 might be above the "full throttle height." But if you're able to get up to FL230 using climb power you shouldn't have any issue maintaining level flight. Only way to get there was 50/2550. Climb rate was less than 100 ft/min at times. 45.5/2350 meant no climb. Mp was falling as I climbed to mid 40’s and less.
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Post by mrcapitalism on Apr 23, 2024 20:20:46 GMT -5
Mp was falling as I climbed to mid 40’s and less. This is with your hardware throttle lever full forward (open)?
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Post by mrcapitalism on Apr 23, 2024 20:28:41 GMT -5
I just poked around the download link you posted and it appears to still be a functional CC B377
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Post by jsaus on Apr 23, 2024 20:32:33 GMT -5
Mp was falling as I climbed to mid 40’s and less. This is with your hardware throttle lever full forward (open)? Yeah. Well, keyboard. Maximum. After 20000 mp drops. I can’t keep 50. Trying to climb at 45/2350 producers no climb. Even at moderate weights.
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Post by jsaus on Apr 23, 2024 20:33:34 GMT -5
This is with your hardware throttle lever full forward (open)? Yeah. Well, keyboard. Maximum. After 20000 mp drops. I can’t keep 50. Trying to climb at 45/2350 producers no climb. Even at moderate weights. I THINK it’s the same one here just with an improved VC and an ‘updated’ FDE which is also from here. I could be wrong though.
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Post by mrcapitalism on Apr 23, 2024 20:56:45 GMT -5
This is with your hardware throttle lever full forward (open)? Yeah. Well, keyboard. Maximum. After 20000 mp drops. I can’t keep 50. Trying to climb at 45/2350 producers no climb. Even at moderate weights. So that sounds like the flight model is working correctly (and gauges). Check the obvious sources of drag. Landing Gear. Flaps. Cowl Flaps. Inadvertent "Phantom" Spoiler activation (a lot of FS aircraft use the speed brakes to augment drag on airplanes not equipped.) What is the status of your automixture in FS? When you set 43/2350, what is the BMEP reading?
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Post by jsaus on Apr 23, 2024 21:10:14 GMT -5
BMEP using 45/2350 at 21000 - current altitude I’m at - is 207 PSI.
No issues with any flaps, gear, etc. cowl flaps do give a LOT of drag even slightly open it seems. I’m not sure exactly what the CHT limit is. On the engineer panel it’s 200. However looking at other sources seem to indicate it’s 250. Impossible not to bust 200 without opening them a reasonable amount. Climb rate kinda very very limited then. At 45/2350 to stay under 200, I couldn’t do it.
If I climb at 45/2350, it will barely climb as I get into the teens. If that’s normal, so be it. Looking at an eat work flight by Pan Am (runaway prop en route SFO from HNL), at 139,000lb or so, they climbed to 13000. Half way they climbed to 21000. Looking at the report it took 18 mins or so. That averages 450 ft/min.
If I climbed at the recommended 45/2350, it would take me 3 times as long and I may not get there. 50/2350-2550 seemed a more realistic figure to use.
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Post by mrcapitalism on Apr 24, 2024 2:26:02 GMT -5
The checklist calls for: during 2nd stage climb, so I think the problem is you have too much drag from excessively open cowl flaps. Use the settings as they are given in the handling notes. also see calclassic.proboards.com/thread/2487/cht
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Post by Tom/CalClassic on Apr 24, 2024 9:53:20 GMT -5
The printed performance figures (like climb to 25,000 ft in 48 minutes) contradict the documented flight behavior of the plane in airline service. FSAviator created an FDE to match actual service performance. A tutorial here: calclassic.proboards.com/thread/3156/377-mini-tutorial
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Post by Defender on Apr 24, 2024 11:58:53 GMT -5
Hi JS,
I notice you refer to using BMEP for power setting and although this was the correct way to set power (except on final approach and landing and never exceeding 60" MAP), FSAviator omits BMEP from his FDE and tutorials, possibly because no accurate gauge or operational settings were available at the time.
Problem is that there is a fault in Bruce Smythe's BMEP gauges and they over-read by about 30%. So at max takeoff power the gauges read 304 whereas the correct BMEP is 235. There are two ways to deal with this, either set BMEP 30% above the setting you want or edit the gauges. In the folder Gauges/XML are two gauges bmep12.xml and bmep34.xml and if you open with notepad you'll see four references in each xml to a figure of 0.045. That ought to be 0.0345.
The great advantage of BMEP is that you can calculate the actual BHP by formula. BHP = RPM x BMEP divided by a constant which for this engine is 181.651. So then BMEP is BHP x constant, divided by RPM.
Here are the settings in the Pan American B377 manual, RPM BMEP BHP MAP CHT(max)
Take off(wet) 2700 235 3500 60.0 249 Meto 2550 203 2850 54.5 249 Climb 2350 187 2650 48.0 232
Hope this helps. I have no problem with climb performance.
Bill
PS #1- The MAP gauges will not show these MAP values accurately so best ignored. It's rare to find a MAP gauge that's accurate because each engine is different. Some do or do not reflect RAM and each engine type has the MAP detector in a different part of the inlet or supercharger area. They all read maximum MAP as that's in the aircraft.cfg but beyond that they vary.
PS #2 - Bruce Smythe's BMEP gauges use a bitmap named TORQUE which might be confusing as he clearly meant these to be BMEP. I think the USAF used torque settings but that has a different constant so 235 BMEP equals 247 torque and needs a different gauge.
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Post by jsaus on Apr 24, 2024 14:09:58 GMT -5
The checklist calls for: during 2nd stage climb, so I think the problem is you have too much drag from excessively open cowl flaps. Use the settings as they are given in the handling notes. also see calclassic.proboards.com/thread/2487/chtI didn't see any mention of the CHT in the notepad I have. It just gives cowl flap recommendations. On the FE panel it has a red line a 200C so I was trying to keep it under that by opening the cowl flaps. Hence the poor climbing performance. Or none at all. Keeping the cowls at 2, and using 45/2350, I was getting a pretty consistent 400-500 ft/min climb rate at 165-170 IAS. So much better.
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Post by jsaus on Apr 24, 2024 14:20:53 GMT -5
The printed performance figures (like climb to 25,000 ft in 48 minutes) contradict the documented flight behavior of the plane in airline service. FSAviator created an FDE to match actual service performance. A tutorial here: calclassic.proboards.com/thread/3156/377-mini-tutorialYeah makes sense. Those charts dont give a gross weight either. Although 48 mins is an average 500 ft/min or so climb rate which I didn't think too high either way. Climbing at 2650 BHP/ENG. Looking at the Pan Am that ditched on the HNL-SFO flight, it took off I think at 139,000lbs. 13,000ft was the initial climb. Half way 5 hours or so(?)average 3200lb/hr fuel burn and now at perhaps 123,000lbs, it climbed to 21,000ft. Based on the notes I have it took 19 mins. Average 420 ft/min. Loaded to basically the same weight I tested it and it took the same time at 45/2350. I ignored the CHT, keeping cowl flaps at 2 although it never got over 220. So it seems its spot on with the performance. I think I was too focused on the CHT red line on the FE panel a 200 and couldn't get any performance out of it.
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Post by jsaus on Apr 24, 2024 14:27:24 GMT -5
Hi JS, I notice you refer to using BMEP for power setting and although this was the correct way to set power (except on final approach and landing and never exceeding 60" MAP), FSAviator omits BMEP from his FDE and tutorials, possibly because no accurate gauge or operational settings were available at the time. Problem is that there is a fault in Bruce Smythe's BMEP gauges and they over-read by about 30%. So at max takeoff power the gauges read 304 whereas the correct BMEP is 235. There are two ways to deal with this, either set BMEP 30% above the setting you want or edit the gauges. In the folder Gauges/XML are two gauges bmep12.xml and bmep34.xml and if you open with notepad you'll see four references in each xml to a figure of 0.045. That ought to be 0.0345. The great advantage of BMEP is that you can calculate the actual BHP by formula. BHP = RPM x BMEP divided by a constant which for this engine is 181.651. So then BMEP is BHP x constant, divided by RPM. Here are the settings in the Pan American B377 manual, RPM BMEP BHP MAP CHT(max) Take off(wet) 2700 235 3500 60.0 249 Meto 2550 203 2850 54.5 249 Climb 2350 187 2650 48.0 232 Hope this helps. I have no problem with climb performance. Bill PS #1- The MAP gauges will not show these MAP values accurately so best ignored. It's rare to find a MAP gauge that's accurate because each engine is different. Some do or do not reflect RAM and each engine type has the MAP detector in a different part of the inlet or supercharger area. They all read maximum MAP as that's in the aircraft.cfg but beyond that they vary. PS #2 - Bruce Smythe's BMEP gauges use a bitmap named TORQUE which might be confusing as he clearly meant these to be BMEP. I think the USAF used torque settings but that has a different constant so 235 BMEP equals 247 torque and needs a different gauge. Ok interesting. I'll mess around with the BMEP gauges. They're in the DC-6 folder. Will that effect the DC-6 now though? Or were they inaccurate too? Interesting the difference with UAL's power settings. Climb (not sure if METO) is 50/2550 at 165 IAS. Then into cruise power of choice. Thanks for the help!
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Post by Defender on Apr 24, 2024 16:23:42 GMT -5
Sounds like you're not using Tom's most recent B377 ual download dated 6/21/2013. It should use B377_panel and you should have a folder in Gauges called XML.
No, do not change the files in Z_DC6KM. They're correctly set up for the Wright R3350 series.
Sorry I haven't got an older B377 panel so can't tell you what to change. Best to download the latest.
Bill
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Post by jsaus on Apr 24, 2024 16:30:15 GMT -5
Sounds like you're not using Tom's most recent B377 ual download dated 6/21/2013. It should use B377_panel and you should have a folder in Gauges called XML. No, do not change the files in Z_DC6KM. Sorry I haven't got an older B377 panel so can't tell you what to change. Best to download the latest. Bill Oh, I thought IS/was the latest with upgrade FDE and VC. Hmmm. I should check.
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