Fuel manual Entry

[Orinks]

Hi Steve and all,

Will the manual fuel entry in Ideal Flight not load a lower amount than what IF thinks the fuel requirement should be?

I am trying to load 29015 LBS into my aircraft, which is a little lower than what IF thinks it should be. Using the once manual option, I got the following:

Fuel Remaining: 1400 Gal, Weight: 9381 Lb, 4255 kg
Fuel Requested: 4331 Gal, Weight: 29015 Lb, 13161 kg
Fuel Required: 4726 Gal, Weight: 31664 Lb, 14363 kg

I'm going to compare the range to what I currently have with my flight last night to see if perhaps it decreased a bit, but that doesn't make sense to me in general.

[Steve Waite]

The outcome is relative to your input in the Range value on the Aircraft Parameters page. Also you can reduce fuel space with loading more cargo. Then there's unusable fuel space. So without that, I can't say what's going on. You need to be careful what you expect to get in there.

[Steve Waite]

So I go for a one off change to the fuel. With the range set at 3200 in the AC130 my flight build says I'll need 2527 gallons.

Remember I've not done a flight in it yet so I have no data. I need to fly it a couple of times and look at the Range calculations in the de-brief. Also I have to be sure to fly the aircraft carefully and repeatably within the parameters I specified with the Range parameter, climb and descent rates and speeds. Differing use of the throttles can have more effects on economy than continuous flight at an average speed.

Anyhow I want to only put in 2200 gallons for this flight for some reason. I Select the fuel button and choose once, and enter 2200. OK. I rebuild the flight. This time the briefing specified I entered my own amount Fuel Requested.

Fuel Requested: 2200 Gal, Weight: 14740 Lb, 6686 kg
Fuel Required: 2527 Gal, Weight: 16931 Lb, 7680 kg
Maximum Fuel Load: 9800 Gal, Weight: 65660 Lb, 29783 kg

Next I put 500 in the Range parameter. More fuel will be needed for the same flight build.

Fuel Required: 9800 Gal, Weight: 65660 Lb, 29783 kg
Maximum Fuel Load: 9800 Gal, Weight: 65660 Lb, 29783 kg

Then I enter the request for a one off build with 9000 gallons and I build the flight.

Fuel Remaining: 9000 Gal, Weight: 60300 Lb, 27352 kg
Fuel Requested: 9000 Gal, Weight: 60300 Lb, 27352 kg
Fuel Required: 9800 Gal, Weight: 65660 Lb, 29783 kg

I see that remaining is the same as requested 9000, and that required is still 9800.

So if you see remaining as already less than requested or required, that's because there's no room, given the aircraft you are using. The aircraft should have accurate values in the aircraft.cfg or things might not look right. In which case you have spotted a problem with the aircraft, or you have cargo weight over-spilled and have no spare weight capacity for fuel.

[Steve Waite]

Notice how we don't know the fuel we are going to use. When I first get an aircraft look up on the manufacturers website at the range and speeds and so on. Put those into the Aircraft Flight Parameters page. Maybe put less range in. A smaller value for range will ensure we can arrive on the fuel loaded. When we complete the flight we get the Range we had in that flight. That is the fuel used compared to the distance flown and the arrangement of climb, descent, level, approach, final, and taxi use of fuel. If we repeat the flight as we did before we use the same fuel. So with that value for range we enter into the page. Next we want to compare the range with other flights. Take a note of the cargo weights flight lengths and compare the Range. The range may be affected by temperature and other aspects of weather. We don't ask IF what fuel we will need, we tell it by flying the aircraft. So it is interesting to compare our fuel calculator with the outcome in IF. As it happens the Range is more or less the same all the time since we don't fly the aircraft at either end of an extreme. We usually have the same cargo and altitudes and speeds and so we get more or less the same range all the time. Range stays with the aircraft in IF, so we set that up each time we choose another.

[Steve Waite]

Any news on this? Aircraft I checked seem to work OK.

I would first check the system with another aircraft that we know, the Mooney is the default aircraft. As always with fault finding we are only chasing our tails if we don't at first check with a known working setup. That may not be working. Then if that is OK we can compare the behaviour with a specific aircraft.

So to check this I would make sure the Mooney works first, with nothing additional to the sim that can affect fuel loads, or even things that can affect the way the Mooney is represented. It should be stock, no mods.

After we are sure we know where we are with that, we can now check a particular aircraft, I would set a small range to increase the requirement for fuel. I would specify a deliberately small cargo payload and see if I can request the maximum fuel quantity. Then I would see if I could request a fraction of the maximum.