Absurd SSJ fuel flow

Unfortunately this data is from the manufacturer of the engines and therefore i cannot contradict or change this.

Could this be a unit-conversion problem?

Defiantly not

There is a miscalculation with fuel flow at this aircraft it's obvious.
We already tried to solve this problem with Northern without any success, and I think I know what is the problem, and I write it down what I've found out, maybe somebody can review this and help us out.


In Airline Empires the actual fuel flow rate calculated the following way for example at a Boeing 787-8 aircraft:
Thrust of the engines: 64000 pounds (x2)
TSFC (Specific Fuel Consumption of the engines): 0.262 (lbm/hr)/lbs
Fuel flow: Thrust x 2 x TFSC = 33536 pounds/hour of fuel consumption

Let's check the Sukhoi Superjet SJ-100-95LR:
Thrust of the engines: 16100 pounds (x2)
TSFC (Specific Fuel Consumption of the engines): 0.629
Fuel flow: Thrust x 2 x TFSC = 20254 pounds/hour of fuel consumption

The above mentioned AE metrics using the maximum thrust and the efficiency of the engines to calculate the actual fuel flow. The problem is, that in the real world the aircraft only operates nearby it's maximum thrust at take off and climb out conditions, which means approx 5-10 percent of the journey for a short range flight, and a bit higher percent for a long range flight (because of the weight of fuel carried).
We will get much higher fuel consumption data with this calculation method, it will describe the airplane, as if it would be in take off/climb out condition for the whole flight.

The main working mode of the engine is the cruise mode at higher altitudes, where it stays for the majority of the journey. This is where the aerodinamics of the plane really kicks in (wingspan, aerod. design, winglets, design cruise speed).
Unfortunatelly we are not counting with this mode in AE regarding fuel consumption.

What is the problem with this Superjet figure?
1, According to Sukhoi the manufacturer of this aircraft the capacity of the fuel tank in the LR version is only 20000 pounds. Which means that if our calculations in AE would be right, this aircraft with fuel reserve requirements, couldn't stay in the air for one hour.

2, If we count with the Sukhoi factory specified fuel flow rate:
-3858 pounds/hr for 95% of the journey (cruise)
-20254 pounds/hr for 5% of the journey (take off/climb out)
-we are not calculating with descent condition
This would mean approx. 4,5-5 hours of max. flight time which is a realistic figure.

3, According to the manufacturer (Sukhoi) the fuel flow rate of this aircraft is in between Bombardier CRJ1000 and Embraer E190's fuel consumption.

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Some actual fuel flow rates quoted by the manufacturer or the operating airline of an aircraft to crosscheck with fuel flow datas in AE:
-CRJ700 1.45 tons / hour -> 3197 pounds / hour
-CRJ900 1.6 tons / hour -> 3527 pounds / hour
-CRJ1000 1.74 tons / hour -> 3836 pounds / hour
-Airbus A320-200 (CFM56-5B) 2.5 tons -> 5512 pounds / hour
http://www.airberlin...0_200&LANG=eng
-Sukhoi SJ-100-95LR 1.75 tons -> 3858 pounds / hour
-A321 3.085 tons -> 6801 pounds / hour
-Boeing B747-400 9,200 kg/hr -> 20283 pounds / hour
-Boeing B767-300ER 5,100 kg/hr -> 13448 pounds / hour
-Boeing B777-200ER 6,900 kg/hr -> 15212 pounds / hour
-Airbus A310-300 5,000 kg/hr -> 11023 pounds / hour
-Airbus A330-200 5,000 kg/hr -> 11023 pounds / hour
-Airbus A340-300 6,800 kg/hr -> 14991 pounds / hour
-Airbus A340-600 8,800 kg/hr -> 19400 pounds / hour
-MD-11 6,800 kg/hr -> 14991 pounds / hour

According to Boeing 787-8 factory specification, this aircraft can carry maximum 148500 pounds of fuel (maximum taxi weight - maximum zero fuel weight):
http://www.boeing.co...df/787_perf.pdf
with our current AE fuel flow rate this would mean approx. maximum 5 hours of flight time without any fuel reserve with this aircraft.

I think with the current metrics of AE the fuel flow rate of the Sukhoi Superjet is in the 13000 range, but maybe an expert can give us advise about reviewing the validity of these fuel flow rates.

To summarize the results the Sukhoi Superjet has a relatively small diameter fan in its engine, because of this, it has to work nearby at its maximum thrust at takeoff, while it can fly in economic cruise mode at it's design fligh level.
Aircraft type - fan diameter (inch):
Sukhoi Superjet S100-95(LR) - 48
Bombardier CS100 - 73
Embraer E190 - 57
A319-100 - 72
A319neo - 81

Because of the current metrics of AE, only the maximum thrust fuel consumption rates matter, the more realistic cruise fuel flow rates are not taken into account, and this penalises this aircraft heavily.

To give an another example about the absurd fuel flows please check the following picture:


This is an actual fuel flow measurement during a flight of a Fokker F100 aircraft where both engines measured separately (blue/red dots).
The fuel consumption measured in KG/hours (1kg/hour means 2,2 pounds/hour)
In AE currently we count with 14496 pounds/hour fuel consumption for this aircraft:
http://ae31.airline-...hp?aircraft=124

As you can see on the above mentioned picture in the first phase of the flight the fuel flow rate is much higher because the engine is in take off/climb out condition.
During take off / climb out the fuel flow rate is decreasing from 2500 kg/hours to 900kg/hours(x2) which means approx. 11023 pounds/hour to 3968 pounds/hour.
This 900kg/hours (x2) 3968 pounds/hour value represents our approx. cruise fuel consumption to the end of the flight where it further decreasing during descent condition.

This example shows, that the SFC and maximum thrust of an engine alone are not contains enough information about the actual fuel consumption and about the charactheristics of an aircraft where it used.
The main parameter, which refers to the actual fuel consumption of a flight is the cruise fuel flow rate (80-90% percent of the flight), which depends from the aerodinamics, wingspan, weight, range, service ceiling, engine efficiency of the actual airfcraft.

Just checking on thr numbers, I noticed that they're much lower now - about in line with the other products. What did you do? Find better numbers or simply use somewhat fictional ones?

We found supplementary data from the EASA - we do not in a ny circumstance make up data