Fuel Flow/Burn
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@dreadnought1906 Simbrief is weird. It likes to order me to the service ceiling of basically everything I fly, including this at 30,000ft. The pressurization panel won't let me set much above 29,000, if that, so I've been doing FL280.
I wonder if our fuel burns are off in the plane, though. I keep setting 840 as the TGT in the TMS but I never get anywhere near it, even with wide open throttles.
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@dreadnought1906 this solution unfortunately doesn't always work - in the lower flight levels in colder-than-ISA conditions, the 600 (lowest possible value) will still bring you to overspeed.
Something is definitely wrong in the flight model...
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I've just been using 820 TGT, which is what it defaults too. Where does it say to use 840? I know in the tutorial video he used that.
And yeah, that new profile it's been wanting me to fly at 31000 the last couple flights but you can't put the cabin that high, and the plane kind of struggles to reach that altitude anyway. 26-28,000 seem ideal.
Off the top of my head I think at cruise my TGT has been like 650 or so??
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@melon between the manual and the video it says 840. I've been trying to find a guide to setting it anywhere, all I can find is that 840 because it's down from the max continuous value of 857, but like I said I don't even think I break 800 at any point.
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My last flight I was showing a Turbine Gas Temperature of about 650 in cruise.
You can dial in a new value via the thumb wheel to fine tune your speed. Only adjust the 10’s digit though as moving the hundreds digit will kick you off of TGT mode (you can re-enable it) -
So far, flying Adelaide to Sydney, with a TGT set to 645 I've been holding Mach .72 pretty solid at FL280 (1hr 10min so far). I easily reached 840 on take off as well, I don't think that has been a problem for me so far afaik (previously had been using 820).
Started with 7060kg of fuel, each engine is burning about 300kg/hr in cruise, burned 2500kg of fuel total according to the planes own gauges, leaving 4511 in the tanks afterwards. So there is definitely some discrepancy with its accuracy in the plane itself, but I figure that is because of the gauge style. Still According to this I should be able to fly back to Adelaide and nearly back to Sydney again, 1800nm total (and this isn't even with a full tank, a full tank is like 9400kg). So it does seem like the numbers a little bit on the low side? Since bad napkin math would put the range at about 2500nm. TBF, I had an average tailwind of like 40knots which would change these numbers a bit, but not that much surely?
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@melon said in Fuel Flow/Burn:
So there is definitely some discrepancy with its accuracy in the plane itself, but I figure that is because of the gauge style.
We've confirmed it in a few other places but yes, the fuel burn (particularly in cruise) and TGTs are currently too low and we're working to address that.
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Typical fuel consumption for BAe 146 during cruise is 2000 kg/h.
To achieve this, simply increase the fuel_flow_scalar value in the engine.cfg file. Standard value is 0.85
I changed it to 1.15 which makes the fuel consumption pretty realistic and in line with the calculations by SimBrief.[GENERALENGINEDATA]
engine_type =1
fuel_flow_scalar= 1.15
min_throttle_limit=-0.21 -
@melon said in Fuel Flow/Burn:
What do the profile options mean?
I found this in a Mahan Air SOP for the BAE146/RJ
4. CLIMB Three climb techniques are recommended: 4.1.1 High Speed Climb (HSC): 280 IAS or 0.60 IMN. Coincident at approximately FL 190. 4.1.2 Long Range Climb (LRC): 250 IAS or 0.60 IMN, coincident at approximately FL 240. 4.1.3 Steep Gradient Climb: 220 KTS (146‐300).This technique can be used to reach a level or altitude by a particular point. For absolute max gradient performance, climb at VER (VFTO +10). Set climb thrust as soon as convenient (observe maximum 5 minutes) after flaps retraction, or at the thrust reduction altitude for the noise abatement procedure. [...] 6.5 DESCENT SPEED SCHEDULE: Two descent profiles are published: 1‐ Long Range 0.6M/250 kt 2‐ High Speed 0.7M/290 kt In practice, any combination of speeds can be used but ATC may require high forward speed to help fit the relatively slow BAe146 into the arrival flow with other, faster jets. For this reason the high speed profile is favored by many operators. Remember, to observe speed limit points and the limitation of 250 kts below 10 000 ft.As for TGT setting, the same SOP has
The normal power climb setting is 840 ºC TGT, although lower TGT may be used to conserve engine life if high climb performance is not required , (i.e.820 ºC) . -
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@melon said in Fuel Flow/Burn:
@johan217 Oh that is really interesting, where does one acquire these sorts SOPs?
Some of these are floating around the interweb. I got this one from scribd (requires subscription, so I don't think I can share the full pdf here, sorry).
