July 25, 2010

Fuel consumption question?

1. Considering that you have palnned a 500 NM flight at an average groundspeed of 120 knots and have determined a fuel consumption rate of 6.5gph., how much fuel should you have on board in order to have a 45 minutes reserve upon arrival at your destination?

2. Assum all the conditions in problem #1 work out as planned. Your fuel tank hold 40 gallons usable, and you departed on thsi trip with full fule. HOw much longer could you fly after reaching your destination and wihtout cutting into the 45 minutes reserve you planned for in question 1?

3. Consider the answer you determined in question2, and assume that you goof and allow an overcast to develop underneath you that prevents you from descending VFR at your destination. A radio check with “Flight Watch” indicates that your alternate aiport, which is 80nm beyond your destination in the same direction. Can you fly to your altenate at a fuel saving groundspeed of 100 knots without running out? (fuel consumption rate is 6.5 gph)

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Tags: Consumption, fuel, Question.

Filed under Gas Conservation FAQ by admin on Jul 25th, 2010. Comment.

Comments on Fuel consumption question?

July 25, 2010

fighterace26 @ 11:53 am

here is a free E6B emulator

Use it!

http://www.csgnetwork.com/e6bcalc.html

rayk469 @ 12:09 pm

For steak: NM is nautical mile, used almost exclusively in U.S. aviation. Same for knot, the speed required to travel one nautical mile in one hour. Covert miles to knots by multiplication: 1 x 1.1516. Of course GPH is gallons per hour. What part of the moon are you from?

Dangergamesinc @ 12:27 pm

I’ve got to be bored.

I’m going to assume no wind, because that’s a factor you seem to have left out Since you’ve referred to groundspeed as your frame of reference, I’ll stay there.

Question 1.
500NM/120kts/hr= 4.16666 hrs.

4.16666 Hrs * 6.5 GPH= roughly 27 gals.

6.5GPH *0.75 hrs= 4.9 Gals Reserve.

27 gals trip fuel+4.9 gals reserve= 31.9

Question 2

40 Gals Total capacity/6.5 GPH=6.15 Hrs.
6.15 Hrs-.75Hrs=5.4 Hrs with .75 Hrs reserve.

Question 3
Yes, without squirm factor.

Tons of variables have been ommitted. Of the variables ommitted, is windspeed, direction, direction of flight, destination airport, altitude, fuel burn which will drop as you slow to a lower airspeed. Another one, which nearly killed a friend of mine, is the amount of time on your engine and whether you’re using the published fuel consumption or flight experience in that particular aircraft.

Your PC has a calculator, your cell phone has a calculator. There’s likely a calculator laying about on your desk. I could do all this long hand if I had to, even having failed basic college mathematics.

Let me urge you not to go into aviation until you can either reliably operate a computer, cell phone, calculator or perform longhand division and multiplication. This sounding like a school homework question, and assuming that it’s not kosher to use a calculator, then using the Yahoo Answers is probably about as kosher as a roast pig at a barmitzvah!