Let’s look at some numbers at semidisplacement speeds. Clearly, there are 4 hydrogen atoms..... Clearly, there are 4 hydrogen atoms, but 2 hydrogen molecules, and 2 oxygen atoms, but 1 oxygen molecule on the left hand side of the equation. Drag can be caused by a fouled propeller or growth on the hull. If 90 minutes makes the difference between arriving at an unfamiliar entrance in daylight or after dark, or avoiding a forecasted increase in wave heights, it is probably worth the additional cost. The given equation is called the differential equation of rocket motion. In this way, the fuel consumption of every aircraft can be … How much fuel will you need if you burn 45 kgs per minute, and are travelling at 465 kts? For all cruising powerboats, when it comes to fuel economy, speed trumps all other factors—but only at slow speeds. For #CO_2# and #H_2O#, this is easy. When comparing two similar boats, fuel-conscious buyers often favor the boat with the smaller engine, assuming it has better fuel economy. © 2021 Cruz Bay Publishing, Inc., an Active Interest Media company. To illustrate this, I will use some numbers from my Shuttle flight, STS 126 in November 2008. Most fossil fuels are hydrocarbons. By applying even more power, these hulls ride more on top of the water. A "nitro-burning" engine and a "top fuel" engine are the same thing -- engines designed to burn nitromethane rather than gasoline. The result depends on the metrics used as input: miles per gallon if the input was in miles and gallons, and km per liter if the input was in kilometers and liters. If you have a boat that will plane, once you get the boat on plane, increases in speed cause much smaller increases in fuel consumption. We wish, but the engine is only making 300 HP. Once you are on plane, increases in speed matter far less, but the importance of a clean underbody and running gear matters far more. The engine converts that energy into the power needed to overcome resistance and move the boat thr… For the purposes of this discussion, we will concentrate on nautical miles per gallon, which we will abbreviate to nMPG. Knowing the fuel consumption of your oil-burning furnace can tell you how long a tank of fuel oil … If we take for example petroleum which is found in the earth and assume we have an oil that has mostly alkenes in it, we can, for example, burn: The fuel cost for an extra 10 knots is only $60. The factors considered include passenger load factor, If this reduction is due to increased drag, we can estimate the impact on fuel burn. Notice that by slowing down 1.5 knots, this boat increases its fuel economy almost 300%. To answer that question we have to introduce the most important variable of all: speed. Why did the plants and animals that make up fossil fuels not rot away? In the following engine performance specs we see that this engine will need 1,450 RPM to produce the same 160 hp. In order to move this hull through the water at 15 knots we need 300 hp. Let’s include the speed and look at the math. Let’s look at some actual numbers from a full-displacement trawler in the 40- to 50-foot range: 7.5 knots @ 3 GPH = 2.5 nMPG, If we push for a little more speed the fuel burn changes: 9 knots @ 11 GPH = 0.8 nMPG. Additionally, the fuel consumption calculator will output the fuel cost per mile or fuel cost per km, depending on the metric units selected, as well as miles per $ / km per $. The extra friction has reduced fuel economy by 17%. Another less recognized side effect of the rocket equation is the sensitivity of completing the rocket burn to obtaining your goal. But if you are running offshore and covering hundreds of miles, these differences accumulate in meaningful ways. Semi-displacement and planing hulls can apply more horsepower and begin to climb up onto the bow wave. All Rights Reserved. At speeds above 1.3 times the square root of the waterline, the burn starts to climb dramatically. Boat-Fuel-Economy | Formula Boats Fuel Consumption | US Gallons, Imp. The other hull types won’t pay a penalty at lower speeds, but at higher speeds the additional weight will take its toll. See all questions in Fossil Fuel Resources and Use. If you burn 24 gallons of fuel per hour to make 300 HP, 142lbs/1 hour, you release 2,699,520 BTU’s of energy, (19,000x 142). How to Calculate Furnace Oil Consumption. The exact evolution of isotopic changes is usually modelled mathematically a set of differential equations known as evolution equations.These equations describe the rate of burnup of U-235, the rate of buildup of Pu-239, production of Pu-240 and Pu-241, the buildup of neutron absorbing fission products, and the overall rate of reactivity change in the reactor due … Reserves can generally be considered 10% of the total amount of fuel capacity for the airplane. This handy nautical mile ruler informs the Pilot In Command (PIC) on his fuel status under VFR conditions. And in some cases the twin engines will burn less fuel than a single, depending on horsepower and propeller configurations. Despite the importance of this topic, confusion and false assumptions abound. Almost all other factors, such as twin engines versus single, high horsepower versus low horsepower, and engine misalignment or binding bearings might individually account for differences of only 5-15%. fuel burn profiles for the A320 is shown on the left side of . Let’s put this information in perspective. The fuel contains the stored energy and we can describe that in terms of horsepower (hp), kilowatts (kW), or British thermal units (BTU). What plants and animals make up fossil fuels? The white FlyGA Cessna 152 Fuel Burn Calculation Ruler is a unique, multi-purpose flight situational awareness tool. Now, the mass of fuel the rocket initially has on board is equal to m 0 – m f. For the constant mass flow rate R it will therefore take a time T = (m 0 – m f)/R to burn all this fuel. Hull shapes can be sorted into three basic categories: full displacement, semi-displacement, and planing. Finally, let’s look at a boat designed for speed, a lightweight planing hull: 7.5 knots @ 2.6 GPH = 2.9 nMPG9.0 knots @ 5.4 GPH = 1.7 nMPG11.0 knots @ 9.2 GPH = 1.2 nMPG15.0 knots @ 14 GPH = 1.1 nMPG25.0 knots @ 27.5 GPH = 0.9 nMPG. Our target velocity at main engine cut off was 7824 m/s (25819 ft/s). This fuel economy calculator will take the distance travelled and the quantity of liquid fuel used by a petrol, gasoline or diesel engine powered motor vehicle, and determine the average fuel economy performance for that journey. Engine misalignment or a binding Cutlass bearing would impact fuel economy in this range. Formula. How do fossil fuels differ from other fuels? Two years ago you attained the rated 3,000 RPM and now you max out at 2,850 RPM. You can test this yourself by filling in a random number for #n# and see if the reaction is balanced. The chemical reaction equation for the complete combustion of methane in oxygen may be written as: CH4 + … Let’s assume that we need 160 hp to achieve our optimum cruising speed of 7 knots. The wide-open throttle (WOT) test described in the previous issue provides the most reliable reference point. Each of these crude oils consists out of a composition of molecules. On average, a four-stroke gasoline engine will burn about 0.50 pounds of fuel per hour per horsepower. 2,699,520/2545= 1061 HP. As speed increases, fuel economy will gradually decline in small increments. And on the RHS, there must necessarily be 4 hydrogen atoms and 2 oxygen atoms, because it is a balanced chemical equation. This chart outlines the maximum temperatures at which common fuel gasses burn along with the melting points of some of the most common metals used in jewelry and metalsmithing. If you burn 24 gallons of fuel per hour to make 300 HP, 142lbs/1 hour, you release 2,699,520 BTU’s of energy, (19,000x 142). The engine converts that energy into the power needed to overcome resistance and move the boat through the water. Fuel burn data (5) – The fuel burn to flight distance relationship is extrapolated from the ICAO Fuel Consumption Formula. Friction and drag also matter. If you are expecting an answer that gives you miles per gallon of fuel used or MPG, that can also be stated as miles/gallon. While many boaters focus solely on gallons per hour (GPH), this is a meaningless number on its own. The above equation is known as the Breguet range equation.It shows the influence of aircraft, propulsion system, and structural design parameters. For example: The above method is therefore highly theoretical and shows only how to write an overall reaction. Given the running speed of 7 knots at 160 HP, we arrive at a fuel burn of 2.6 nMPG—a 30% improvement over the smaller engine. Minimizing Fuel Consumption Avoid using the air conditioner. The chemical reaction equation for the complete combustion of methane in oxygen may be written as: CH4 + 2O2 CO2 + 2H2O (3.1) (Typically less than 1.2 times the square root of the waterline length will be a sweet spot.) The combustion is possible even is the AFR is different than stoichiometric. This same data answers a similar question: “What happens if I run my twin-engine boat on one engine?” At displacement speeds you can read the math above in reverse order and you have the answer: changes in fuel consumption will be minor again, probably within 10%. What are the pros and cons of fossil fuels? Integrating both sides of the equation with respect to time from 0 to T (and noting that R = dm/dt allows a substitution on the right), we obtain allows estimation of the total fuel use on each route serving the user-defined city-pair. kgs: You burn 12 kgs of fuel per hour. Zimmerman has been building and repairing boats for more than four decades. Full displacement boats live in this zone. If it is allowed to freewheel, we have to be concerned about the spinning transmission and the shaft seal. Our expert troubleshooter, Steve Zimmerman, unpacks the often confusing metric of fuel burn. The stoichiometric air-fuel ratio is an important parameter of fuels. In this particular example, we see that although the difference is minor, the boat burning more gallons per hour achieves better mileage. For example, here’s a question: Which is more efficient, Boat A burning 11 GPH or Boat B burning 22 GPH? Equations: To find the time it takes to travel a given distance at a given speed, use the following equation: To find the airplane's fuel consumption: Note: Total fuel is considered the total amount of fuel excluding any fuel reserves. This article describes this ratio and presents an easy way to calculate it when the composition of a fuel is known. And on the RHS, there must necessarily be 4 hydrogen atoms and 2 oxygen atoms, because it is a balanced chemical equation. Let’s assume that over a period of a year or two you’ve noticed a gradual increase in the RPM needed to achieve the same speed. It should also be pointed out that weight matters, but it matters considerably less at displacement speeds. Misc. But remember our initial premise that it takes a given amount of energy to move a given hull form through the water at a given speed. Now we have enough information to write this: If you have a twin-engine boat, can you run on one engine to reduce fuel burn? Gallons per hour can be helpful when calculating range and determining whether you have enough fuel to get to your destination. If we put two smaller engines—say, 220 hp each—in the same boat we still need roughly the same horsepower to reach 15 knots. If we power the boat with a single 370 hp engine we must run at 2,800 RPM to reach 300 hp. The #n# is a placeholder for an unknown number. Without calculating miles per gallon (MPG) it is impossible to say. These equations describe the rate of burnup of U-235, the rate of buildup of Pu-239, production of Pu-240 and Pu-241, the buildup of neutron absorbing fission products, and the overall rate of reactivity change in the reactor due to the changing composition of the fuel. Stoichiometric or Theoretical Combustion is the ideal combustion process where fuel is burned completely. Now we can look at the same specs to estimate fuel consumption: At 7 knots we will burn 3.5 GPH, resulting in a fuel economy of 2 nMPG. The evolution equation can be constructed for each isotope. The environmental impact of burning fuel is not considered in this report. Therefore we must balance the reaction by multiplying the reactants and the products with a form of #n#. For example, if the ship's motor consumes 1,660 gallons of diesel fuel per hour, multiply the number of hours in transit by the hourly fuel consumption, thus: 177 x 1,660 = 293,820 gallons of fuel. Results showed that a maximum fuel burn reduction of 3.5% is possible in cruise given complete altitude and speed optimization; this represents 2.6% fuel reduction system-wide, corresponding to 300 billion gallons of jet fuel and 3.2 million tons of % 1 6 saved annually. Hourly Fuel Consumption Calculator, calculate the fuel burned by hour during a flight. This data point illustrates the value of keeping a log, or at the very least noting your baseline when all conditions are good. This effect becomes far greater at planing speeds. On average, an in-tune four-stroke gasoline engine will burn about 0.50 pounds of fuel per hour for each unit of horsepower. The demand for speed drag can be created by engine misalignment or a worn bearing on! Of a fuel is determined and a chemical reaction can be written.! Consumption of the waterline length will be a problem and structural design parameters is the sensitivity completing! 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Why did the plants and animals that make up fossil fuels not rot away the easily! Side effect of the fuel burn the impact on fuel burn cost for an extra 10 knots only! Increases drag and fuel economy throttle to achieve our optimum cruising speed of 7 knots discussion, are... Numbers someone is telling you are real or not agree that MPG is our standard gallons,.! Flyga Cessna 152 fuel burn data ( 5 ) – the fuel checking! In practice, the boat with the smaller engine, assuming it has better economy... Applying even more power, these hulls ride more on top of the rocket to!