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18.28.10 Calculate the fuel burn rate, given the consumption

18.28.10 Calculate the fuel burn rate, given the consumption and time.


Example 1.

You have flown your Cessna for 45 minutes, and worked out that it will have consumed 20 litres of fuel. How much fuel is your aircraft using per hour (in litres)

Setup

1. Find the 20 Litres on the outside 


2. Set 45 minutes on the inside (as is almost always on the inside scale is time)

Read off

3. Find the 60 minutes  /1 Hour on the inside time scale.

4.  Read off the outside 24 . which the litres this aircraft would use in 1 hours.

101011111212131314141515161617171818191920202121222223232424252530303535404045455050555560607070808090901. Outer Find fuel flow of 182. Inner lineup '45 minutes'4. Outer read off '24'3. Inner find '60 minutes /1 Hours'

(c) the various New Zealand aeronautical charts



The NZ aeronautical charts contain information including airspace, aerodromes, latitude and longitude, heights, and ground features to name a few. 


Aeronautical charts are used for navigation and reference to frequencies and airspace boundaries. A pilot cannot navigate or plan to fly anywhere without the proper and current charts. 





 
        

         
    

     

    

         

        

             

             
        

    



  


    

        
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PNR Quiz


         
    


     
    

        

Quizz One


Example of PNR.
 You planned a flight with distance of 357 nm and your safe fuel Enduance is 3.2 Hours

    with a 'Ground Speed Out' of 120 and 'Ground Speed Home'170 
 

    What is your PNR (Point of No Return)?

		  

			

			  

				The Answer is  ...
			  

			

			

			  

			
			
			A
			
			B
	TAS of 145kts, Distance 357nm
					
					<-<- Head-Wind of 25kts
					
					
						
						225nm <- PNR
					
					

		
To check your Answer ...

		

			
To fly out to 225 mn at 120 kts will take 113 Minutes or 1.9 Hours

              
                10101111121213131414151516161717181819192020212122222323242425253030353540404545505055556060707080809090GS Out 120 1 Hour locate Distane of 225read off Time = 113 Minutes
To fly back to Departure Airport from  225 mn at 170 kts will take 79 Minutes or 1.3 Hours

  Time Out of 1.9 Hours plus time back home of 1.3 Hours = 3.2 Hours

              
                10101111121213131414151516161717181819192020212122222323242425253030353540404545505055556060707080809090GS Home 1701 Hourlocate Distane of 225read off Time = 79 Minutes

			

		

		  

			

			  

				Calulate with Nav Computer ... ...
			  

			

			

			  

              
                10101111121213131414151516161717181819192020212122222323242425253030353540404545505055556060707080809090GS Home 170GS Out 120+Home 170=290read off PNR  = 209 nm locate Distane of 357
For the Nav Computer ** Working Yet *** 

\( \frac{ G/S\ Home}{G/S\ On\ +\ G/S\ Home} \) = \(  \frac{Distance\ To\ PNR }{Distance} \) 

			  

			

		  

		


			  

			

		  

		




 
        

         
    

     

    

         

        

             

             
        

    



  


    

        
18.28.8 Calculate fuel consumption, given the burn rate and


         
    


     
    

        
Compute fuel consumption, given the burn rate and time.
Explain: Fuel Consumption 





Fuel Calculations are basically the same as Distance , Time and Speed 


just swap DISTANCE for FUEL











Example 1.


Our Cessna is burning 25 litres an hour,  what will this aircraft burn in 90 minutes?








Setup 








1. Find the 25 on the outside 




2. Set 60/Hour on the inside (as is almost always on the inside scale is time)






Read off








3. Find the 120 minutes on the inside time scale.


4. Read off the outside 50, which the litres this aircraft would use in 120 minutes or 2 hours.








              
                101011111212131314141515161617171818191920202121222223232424252530303535404045455050555560607070808090901. Outer Find fuel flow of 252. Inner lineup '60/Hour'4. Outer read off '50'3. Inner find '120  minutes'

 

 
        

         
    

     

    

         

        

             

             
        

    



  


    

        
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PNR – Calc on a Nav Computer


         
    


     
    

        


In this example we take look at working out a Piont of No Return (PNR),


Lets take our Auckland to Norfolk flight example at 580nm.


With a True Airspeed of 200kts and Head wind of 40kts.


Example of PNR.

			
			
			A
			
			B
	TAS of 200kts, Distance 580nm
					
					<-<- Head-Wind of -40kts
					
					
						
						0nm <- PNR
					
					

		
To check your Answer ...

		

			
To fly out to 0 mn at 240 kts will take 0 Minutes or 0 Hours

              
                10101111121213131414151516161717181819192020212122222323242425253030353540404545505055556060707080809090GS Out 240 1 Hour locate Distane of 0read off Time = 0 Minutes
To fly back to Departure Airport from  0 mn at 160 kts will take 0 Minutes or 0 Hours

  Time Out of 0 Hours plus time back home of 0 Hours = 0 Hours

              
                10101111121213131414151516161717181819192020212122222323242425253030353540404545505055556060707080809090GS Home 1601 Hourlocate Distane of 0read off Time = 0 Minutes

			

		

		  

			

			  

				Calulate with Nav Computer ... ...
			  

			

			

			  

              
                10101111121213131414151516161717181819192020212122222323242425253030353540404545505055556060707080809090GS Home 160GS Out 240+Home 160=400read off PNR  = 232 nm locate Distane of 580
For the Nav Computer ** Working Yet *** 

\( \frac{ G/S\ Home}{G/S\ On\ +\ G/S\ Home} \) = \(  \frac{Distance\ To\ PNR }{Distance} \) 

			  

			

		  

		




 
        

         
    

     

    

         

        

             

             
        

    



  


    

        
Speed


         
    


     
    

        
To work out your speed you need to know first ….


1. Distance travelled.


2. Time taken.




In this example we have to calculate the speed of our aircraft across the ground, Lets say we have flown 34 nm in 14 minutes.




On the Wizz wheel, Distance is on the out side and time is on the inside.


1. Distance of 34 on the outside 


2. Time on the inside of 14 mins.


              
                101011111212131314141515161617171818191920202121222223232424252530303535404045455050555560607070808090901. Outer Find Distance of '34'2. Inner lineup '14 Minutes'

 Now we have Distance and Time Ratio setup.




3. Find the time of 60 / Hour on the inside (as time is on the inside).


4. Read off the speed of 146 the on outside. This is distance in an hour,thus your speed is 146 knots



              
                101011111212131314141515161617171818191920202121222223232424252530303535404045455050555560607070808090901. Outer Find Distance of '34'2. Inner lineup '14 Minutes'4. Outer read off '146'3. Inner find '1 Hour'

    



 
        

         
    

     

    

         

        

             

             
        

    



  


    

        
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PNR – Formula Explained


         
    


     
    

        


Here is the Formula to the Point of No Return.


Point of No Return(Distance)  = ( frac{Endurance x Ground Out Home x Ground Speed Home}{Ground Speed Out + Ground Speed Home} )


Point of No Return(Time)  = ( frac{Endurance x Ground Speed Home}{Ground Speed Out + Ground Speed Home} )



Point of  No Return (PNR)



Endurance
Ratio / Time
Distance






Endurance x         
( frac{ Ground Speed Home }{Ground Speed Out + Ground Speed Home} )      
 x  Ground Speed Out




Step 1
Total Endurance
 less Reserve 


Step 2
Fuel Endurance x this Ratio 
will equal the Time 
to your PNR from departure airport.		
Step 3
Than Time to PNR 
x Ground Speed Out
will given you the Distance to PNR.     		






Trial and error Method.


if all else fails or as a double check.


This formula is handled to understand to help make a quick estimate of roughly where your PNR is.


Given what is at stack it is problem better to use a trial and error method, 


by using on your nav computer with the ( frac{Ground Speed}{1 Hour} )  or ( frac{Distance}{Time} )