2.31 How do I get accurate fuel burn rates in FS98 aircraft models?

From FlightSim

Q:

HOW DO I GET ACCURATE FUEL BURN RATES IN FS98 AIRCRAFT MODELS?

A:

I have yet to find a model built to accurate specs that doesn't also have reasonably accurate fuel burn! I have even done a "personal" Concorde to accurate specs which flies and burns accurately (about 1/4 of the fuel burn of the STOL FSD Concorde).

It is VERY important to:

a) Understand that FS models must be modeled to the proper Max. Gross Takeoff Weight (MGT or MOW) and wing geometry (area and span). Far too many use lesser weights and random wing numbers - with all sorts of lift, drag, moment, consumption and handling consequences.

b) Understand that quoted "Range" figures can be based on all sorts of standards - resulting in up to a 10:1 spread of figures for the same plane from different sources.

The biggest problem with jets is the difference between "Range at Max. Payload" and "Range at Max. Fuel".

The biggest problem with recips is knowing what engine settings have been used (50%, 65%, 75% power - combined with max or other leaning). Altitude is also highly relevant.

For example, quoted range for an Embraer 110 Bandeirante (turboprop) at max payload at eco-cruise speed and altitude is just 173 miles, but with max fuel it is 1,191 miles. A DHC-6 Twin Otter (turboprop) at max payload should only travel 115 miles, but at max fuel it should go for 1,103 miles. A DC-4 (recip) at max payload is quoted at 1,150 miles but at max fuel is 2,180 miles. Passenger jets are usually quoted at typical passenger loads (which will be somewhere in between max payload and max fuel).

Ian Donohoe