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Q. How much extra fuel do I burn while climbing to altitude? A. Fuel burn= 43gph for the initial climb. Additional fuel burn over cruise for climb = 43-29gph = 14gph. 14gph x 1/4hour for the climb = 3.5 gallons. Climbing is fast and cheap. |
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Did you know that it takes about 16 gph to run the compressor in the engine. A helpful insight is to add about 14 gph to the normal fuel burns you now experience. A big difference from the piston engine is that the jet engine burns 1 gph less for the same power setting for every 3,000 feet you climb. This is why you shoot for the Flight Levels every time you fly. |
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The fuel was increased from 120 gallons to 151 gallons. 20 of these gallons comes from replacing 20 of the 28 gallons of air in the wings with fuel. The other 11 gallons is a header tank that is added to the front storage area. The baggage in the front storage area is reduced from 100 lbs to 30 lbs, thus allowing 70 lbs for the header tank fuel. The weight of the fuel increases from 6.0 to 6.7 lbs per gallon for Jet-A. Net result is 720 lbs of fuel before to now 1,011 lbs.
It takes getting use to having the pumps run and lights come on about every 5 minutes to fill the header tank. |
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Part of the conversion is a Shaden Trend Monitor. It logs many parameters of the engine every half hour. (If that is where you have it set) It also does nav data like TAS, ETA, ETE etc. A big item is fuel management. Fuel burn, time and fuel left and all the normal goodies. It also calculated Specific Range (SR), which is mpg over the ground. When you change any of your flight setting like power etc. it shows you the results of your change and helps you find the optimal configuration to use, including altitude. |
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RANGE * WEIGHT & BALANCE * NEEDED FUEL * SR I have put two charts together in Excel. One is to determine the weight and balance for my airplane. The empty weight is different for each airplane, so that number will need to be changed for your airplane.
The second chart is to determine the fuel needed for a specific distance and head wind. The flight data for specific altitudes and power settings are taken from your POH. Fuel reserves you feel comfortable with are entered in the header. I personally like to land with at least one hour of fuel in my wing tanks plus the header tank. (an additional 20 minutes) You can then look at the chart and determine the amount of fuel you need in the wing tanks for the flight distance and wind condition.
By using both charts you can determine if you need to stop for fuel, or even if the flight is a go. By comparing the SR (Specific Range) numbers on the chart and what you are getting in actual flight you can confirm the accuracy of your calculations.
I printed out typical profiles that I find myself using and keep them in my flight bag. I have found the numbers to be very accurate in determining range and/or fuel needed for a specific distance. Several other users of these charts have found them accurate. You are welcome to download and use these charts.
I make no specific claims as to the accuracy of these programs. It is your responsibility to determine what is safe for your flight. |
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Wheel Well Fairings
JetPROP has recently made available fairings to reduce the drag from the wheels protruding below the wings. I have had a problem of the air building pressure above the wheels and pushing the wheels down. My gear warning light came on and my airspeed decreased about 5 knots. Digging deeper into the problem, the increased air speed builds pressure above the main wheels and pushes them down enough to open the gear door switch. This adds about 5 KTAS of drag. Adjusting the wheels higher in the well and increasing the tension on the doors solved the problem. These adjustments are critical with no room for slop.
Back to the wheel fairings. Comparing data from the Shaden before and after the fairings were added, the IAS at FL270 increased from 148 to 155 KIAS, or 11 KTAS. At 800 lbs torque, which is what I normally run, the KTAS went from 141 to 152. Maximum torque at FL270 is about 860 lbs, or 162 KTAS.
This is a great upgrade and really works. |
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Take a ride with me from Vero Beach to Hilton Head Island. The Shaden Engine Monitor tells it like it really is. A lot of data, but some like it that way.
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