AVIATION GRADE ETHANOL 85 (AGE-85) TECHNICAL BRIEFING Dr. Dennis Helder Director of Eng. Research South Dakota State University Brookings, SD Mr. Jack Johnson, Pres. Texas Skyways, Inc. Boerne, TX Mr. James Behnken, Pres. Great Planes Fuel Development Inc. Brookings, SD 57006

What AGE-85 is: It is an Ethanol-based fuel designed for piston aircraft It is better: safer, more efficient, and cleaner It is a replacement fuel for 100LL What AGE-85 is not: It is not 100LL It is not Ethanol It is not E-95: 95% Ethanol & 5% Avgas It is not from Baylor University

DESIGN 1. Compatible with existing aircraft 2. Compatible with 100LL 3. Optimal RVP alone or mixed with 100LL 4. 12:1 100LL Air/Fuel ratio 10:1 AGE-85 Air/Fuel Ratio 5. Biodiesel lubricant 1. Upper cylinder lubricant 2. Engine storage 3. Fuel system protection 4. Larger particulates

SPECIFICATION Fuel Description Aviation-grade E85 refers to a reciprocating-engine aviation fuel that contains about 85 volume percent (vol%) ethanol and about 15 vol% “pentane isomerate” (an oil refinery product comprising about 35 vol% isopentane), in addition to small amounts of soy methyl ester lubricant and a fatty acid-based corrosion inhibitor. Variation in fuel ethanol content from a minimum of 80 vol% to a maximum of 90 vol% may be needed to meet fuel volatility requirements based on seasonal considerations and/or refinery-specific pentane isomerate vapor pressure.

SPECIFICATION Fuel Composition 1) 80 to 90 vol% nondenatured ethanol meeting fuel grade certification specifications as described by: ASTM D1613 (Acidity) ASTM D512 (Chloride) ASTM D1688 (Copper) ASTM D5501 (Ethanol Purity) ASTM D381 (Gum) ASTM E1064e (Water by Karl Fischer for Ethanol) 2) 10 to 20 vol% pentane isomerate oil refinery stream (a high saturates-, low aromatics-, low olefins-content product) comprising: 25 to 35 vol% isopentane 10 to 30 vol% n-pentane 10 to 20 vol% 2-methylpentane 5 to 10 vol% 3-methylpentane 2 to 10 vol% 2,2-dimethylbutane Up to 45 vol% other saturates Less than 3 vol% benzene 3) 0.5 to 1.0 vol% biodiesel 4) About 6 milliliters per 100 gallons corrosion inhibitor

SPECIFICATION Fuel Properties/Specifications Reid vapor pressure, psi6.5 to 8.5 Minimum net heat of combustion, Btu/gallon88200 Density,  F6.3 to 6.5 Maximum sulfur content, weight%0.05 Maximum water content, weight%1.0

SPECIFICATION Properties and Composition of NCRA Pentane Isomerate (Tipate) Pentane isomerate or “tipate” produced by NCRA refinery in McPherson, Kansas, is a relatively light, high-octane, highly isoparaffinic mixture normally used as a gasoline blendstock. Because tipate has essentially no olefins, aromatics (including benzene), or sulfur, it is ideally suited for use as an aviation gasoline blendstock. Current Federal Aviation Administration (FAA) -certified aviation gasolines are composed of paraffins and isoparaffins (50 to 60%), lesser amounts of naphthenes or “cyclics” (20 to 30%), small amounts of aromatics (up to 20%) and usually no olefins. Under conditions of use in aircraft, olefins have a tendency to form gum and cause preignition, and have relatively poor antiknock characteristics under lean-mixture (cruising) conditions; for these reasons, olefins are detrimental to aviation gasolines. Aromatics have excellent antiknock characteristics under rich-mixture (takeoff) conditions, but are much like olefins under lean-mixture conditions. Under American Society of Testing and Materials (ASTM) Designation D910–97 “Standard Specification for Aviation Gasolines,” sulfur content for all aviation gasolines is limited to a maximum of 0.05 mass% because products of sulfur combustion can cause corrosive wear of engine components. Tipate Composition ComponentApproximate Volume% Isobutane1 normal Butane1 Isopentane53 normal Pentane4 Dimethylbutanes11 Isohexane23 normal Hexane1 Cyclohexane5 Total99

SPECIFICATION

AIRCRAFT CONVERSION 1. Increase fuel system flow capacity by 20%. 2. Ensure material compatibility of the fuel system 3. Critical performance parameters 4. Specific flight tests

AIRCRAFT CONVERSION 1. Increase fuel system flow capacity by 20%. Typical aircraft systems allow 12:1 air/fuel ratio at full rich Increase fuel flow capacity to allow 10:1 air/fuel ratio on AGE-85 --full rich on AGE-85 at sea level temp./press. “Mixtures as rich as 8:1 and as lean as 16:1 will burn in the cylinder of an engine that develops maximum power with about a 12:1 ratio.” --Flight Training Handbook, AC 61-21A “Gasoline, the aromatics, and alcohol are the ideal fuels for internal-combustion engines.” --Aircraft Powerplants, 7th Ed., Glencoe Division, Macmillan/McGraw-Hill.

AIRCRAFT CONVERSION 2. Ensure material compatibility of the fuel system Metal components have shown no corrosion in 3 years --Biodiesel provides added protection Most polymer materials used in aviation the past 15 years are alcohol compatible Parker Seals: Ethylene Propylene is best for alcohol Nitrile Rubber is best for gasoline Fluorosilicones work well in both Floats and Fuel Cells: After 18 months of use with AGE-85, nitrile rubber fuel cells in the certification aircraft showed no abnormal aging or deterioration. In comparison to toluene in 100LL, ethanol and Biodiesel may prolong the life of fuel bladders and fuel system components.

AIRCRAFT CONVERSION Aging in(V737-75)Distilled WaterIso OctaneMethanol o F Hardness, Type A, (Chg., pts.)73 (-1)73 (-1)80 (+8) Tensile Strength, psi (Chg.,%)1830 (+5)1880 (+8)1770 (+3) Elongation, % (Chg., %)242 (+15)218 (+4)210 (+0) 100%, psi (Chg., %)623 (-3)707 (+10)789 (+22) Volume Change, % Parker Seals R&D Laboratory Report No. D3486 April 20, 1984 Evaluation of Parker Compounds V and V in Selected Fluid Materials Conclusions: “Both Parker fluorocarbon [EP] compounds show generally good resistance to the fluid media….”

AIRCRAFT CONVERSION 3. Critical performance parameters % 100LL is the critical blend for engine cooling tests % 100LL is the critical blend for detonation testing % AGE-85 is the critical blend for fuel flow testing % AGE-85 is the critical blend for engine restart testing % AGE-85 is the critical blend for hot fuel tests.

AIRCRAFT CONVERSION Addition of Aviation Grade E85 (AGE85) to 100LL Effect on Volatility Ted Aulich Energy & Environmental Research Center Grand Forks, North Dakota, July 9, % AGE-85 is the critical blend for hot fuel testing since this blend encompasses the operational extreme of both liquid vapor ratio and RVP.

AIRCRAFT CONVERSION 4. Specific flight tests 1. Vapor lock --hot fuel climb test 2. Operational flight test on AGE Operational flight test on 100LL Operational flight tests should include: engine start, run-up, climb, cruise, descent, traffic pattern, landing, go-around, and in-flight engine restart.

Operation & Safety 1. Detonation 2. Mixture Settings 3. Flame visibility and explosive potential 4. Water and AGE-85

Operation & Safety 1. Detonation Alcohol-based fuels cannot be made to detonate under virtually all flight conditions. AGE-85 certification required full power climbs with engine full rich, at peak EGT, and leaned 100 o C lean of peak EGT. No detonation was detected. “This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Motor octane number except, that this test method may not be applicable to fuel and fuel components that are primarily oxygenates” --ASTM Std. D a Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel.

Operation & Safety 2. Mixture Settings Full rich is the stoichiometric point at sea level. Rich misfire does not occur until above 10,000’ density altitude on AGE-85. (Similar to unmodified aircraft on gasoline). 100 o C lean of peak EGT is a typical low power cruise setting. Mixture may be safely varied over a much broader range with AGE-85 than with 100LL.

Operation & Safety 2. Mixture Settings WHEN TO LEAN: Lean anytime the power setting is 75% or less at any altitude. (Full throttle or climb power through 5000 feet density altitude usually means mixture full rich.) At high altitude airports, lean for taxi, take-off, traffic pattern entry and landing. For landings at airports below 5,000 feet density altitude, adjust the mixture for descent, but only as required-- --You can’t go wrong if you keep the engine running smoothly. --Before entering the traffic pattern, go to full rich. In any event, always consult your Pilot’s Operating Handbook for the proper leaning procedures. --How to Lean Direct Drive Normally Aspirated Engines, A Cooperative Project by the: Federal Aviation Administration, General Aviation Manufacturers Association, AVCO Lycoming--Williamsport Division.

Operation & Safety 2. Mixture Settings Standard leaning procedure for AGE-85, 100LL, or blends: Lean for maximum power. This is the same procedure prescribed for high density altitude operations. It is taught to every pilot. It is safer since now only one procedure needs to be followed.

Operation & Safety 3. Flame visibility and explosive potential AGE-85 flame visibility is within 98% that of 100LL. “If the fuel flame of the alternate fuel is not visible when the fuel is burning, then some means of making the flame visible should be provided. The flame should be as visible as that produced by ethanol burning in bright sunlight.” Type Certification of Oxygenates and Oxygenated Gasoline Fuels in Part 23 Airplanes With Reciprocating Engines, AC AGE-85 is a conductive liquid. Less danger of static electricity build-up during fueling operations.

Operation & Safety 4. Water and AGE-85 Ethanol and water are perfectly miscible. INDUCTION SYSTEM ICING. Induction system icing may be characterized as Impact Ice, Throttle Ice, and Fuel Vaporization Ice. Impact Ice--Impact ice is formed by moisture-laden air at temperatures below freezing, striking and freezing on elements of the induction system which are at temperatures of 32 o F or below. Under these conditions, ice may build up on such components as the air scoops, heat or alternate air valves, intake screens, and protrusions in the carburetor. Throttle Ice -- Throttle ice is usually formed at or near a partially closed throttle, typical of an off-idle or cruise power setting. This occurs when water vapor in the air condenses and freezes because of the cooling restriction caused by the carburetor venturi and the throttle butterfly valve. The rate of ice accretion within and immediately downstream from the carburetor venturi and throttle butterfly valve is a function of the amount of entrained moisture in the air. Fuel Vaporization Ice -- This icing condition usually occurs in conjunction with throttle icing. It is most prevalent with conventional float type carburetors, and to a lesser degree with pressure carburetors when the air-fuel mixture reaches a freezing temperature as a result of the cooling of the mixture during the expansion process that takes place between the carburetor and engine manifold. --Pilot Precautions and Procedures To Be Taken In Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems, AC Throttle Ice and Fuel Vaporization Ice are no longer a problem with AGE-85.

Operation & Safety 4. Water and AGE-85 Ethanol and water are perfectly miscible. FUEL SYSTEM ICING. Ice formation in the aircraft fuel system results from the presence of water in the fuel system. This water may be undissolved or dissolved. One condition of undissolved water is entrained water which consists of minute water particles suspended in the fuel. This may occur as a result of mechanical agitation of free water or conversion of dissolved water through temperature reduction. Entrained water will settle out in time under static conditions and may or may not be drained during normal servicing, depending on the rate at which it is converted to free water. In general, it is not likely that all entrained water can every be separated from fuel under field conditions. The settling rate depends on a series of factors including temperature, quiescence and droplet size. a. The droplet size will vary depending upon the mechanics of formation. Usually, the particles are so small as to be invisible to the naked eye, but in extreme cases, can cause slight haziness in the fuel. Water in solution cannot be removed except by dehydration or by converting it through temperature reduction to entrained, then to free water. b. Another condition of undissolved water is free water which may be introduced as a result of refueling or settling of entrained water that collects at the bottom of a fuel tank. Free water is usually present in easily detectable quantities at the bottom of the tank, separated by a continuous interface from the fuel above. Free water can be drained from a fuel tank through the sump drains which are provided for that purpose. Free water frozen on the bottom of reservoirs, such as the fuel tanks and fuel filter, may render water drains useless and can later melt releasing the water into the system thereby causing engine malfunction or stoppage…. c. Water in suspension may freeze and form ice crystals of sufficient size such that fuel screens, strainers, and filters may be blocked…. --Pilot Precautions and Procedures To Be Taken In Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems, AC Fuel system icing is no longer a problem with AGE-85.

Engine Wear After 500 hour endurance flight testing per FAA certification requirements, the hottest running cylinder was disassembled and inspected. There was virtually no wear! Substantial improvement in engine durability is indicated. Engine oil analysis every 25 hours indicated substantially less metal in the oil as compared to 100LL.

Engine Wear Corrosive Effects of Leaded Fuels “As previously stated, TEL is used with aviation fuels to improve the antiknock quality. Also, the use of TEL requires the addition of a bromide compound to help reduce the accumulation of lead deposits inside the combustion chamber. The bromide compound used commonly is ethylene dibromide. The burning of TEL and ethylene dibromide produces the compound of lead bromide, most of which is carried out of the exhaust cylinder with the exhaust gases. However, a certain amount will remain, even under the best conditions. Lead bromide in the presence of water and metals, particularly, aluminum, produces corrosive liquids, particularly hydrobromic acid, which cause rusting of steel and cast iron.” -- Aircraft Powerplants, 7th Ed., Glencoe Division, Macmillan/McGraw-Hill.

Engine Performance The engine typically runs o F cooler on AGE-85 as compared to 100LL at similar power settings. At low altitudes, fuel flow is typically 10% greater on AGE-85. As altitude increases fuel flow decreases until at approximately 13,000 feet fuel flow meets POH values on 100LL, and is less at higher altitudes.

Engine Performance

AGE-85 and Water No problems with AGE-85 and water exist if normal pre-flight procedures are followed! Water in AGE-85 fuel is easily detectable by sumping the fuel system. A hydrometer can be used to accurately measure the water content. A specific gravity of 0.80 will determine bad fuel before any phase separation occurs. Fuel sample cups can be obtained with floating balls of desired specific gravity. Specific Gravity Water 1.00 AGE LL 0.72 “Dissolved water is not a problem for aircraft operation as long as it remains in solution” --Water in Aviation Fuels, AC AGE-85 can hold 10% dissolved water before any phase separation occurs.

AGE-85 and Water WATER IN AVIATION FUELS AC Purpose. This advisory circular (AC) alerts the aviation community to the potential hazards of water in aviation fuels. In addition, it outlines recommended procedures to prevent, detect, and eliminate water in the fuel systems of aircraft. 2. Background. Water in fuel continues to contribute to aircraft incidents and accidents and, at times, fatal accidents…. 4. a. Dissolved Water. All aviation fuels dissolve water in varying amounts depending upon the fuel composition and temperature…. 4.a.(2) Dissolved water is not a problem for aircraft operation as long as it remains in solution…. 5.b. Smaller amounts of entrained water can be detected by testing with a clean and dry clear glass bottle. If fuel is acceptably dry it will appear bright with a fluorescent appearance and will not be cloudy or hazy. The clear and dry bottle test is known as the “clean and bright” test. The fuel is clean when it is clear and is bright when it is dry. The container should be large enough to provide for a test sample of 10 ounces or more. 6.d. Flight personnel. The owner/operator of an aircraft should be intimately familiar with the fuel system of the aircraft. This familiarity should include the knowledge of the specific requirements for the prevention, detection, and elimination of water in the aircraft fuel system. (1) The pilot-in-command has the final responsibility to determine that the aircraft is properly serviced. An important part of the preflight inspection is to drain aircraft fuel tank sumps, reservoirs, gascolators, filters, and other fuel system drains to assure that the fuel supply is free of water. A review of National Transportation Safety Board Briefs of Aircraft Accidents involving 114 accidents due to fuel contamination with water occurring between January 7, 1980, and September 11, 1981, showed that the probable cause in 85 of those accidents was “Pilot-in-Command -- Inadequate Preflight Preparation and/or Planning.” Since water in fuel accounts for a major share of fuel quality accidents, pilots should make it a practice to include this check beginning with the next preflight inspection.

AGE-85 and Water WATER IN AVIATION FUELS AC (con’t.) 7.c.(4). During preflight, a generous sample of gasoline (10 ounces or more) should be drained into a transparent container from each of the fuel sumps and from the main fuel strainer or gascolator. Visually check the fuel sample for water and by the clean and bright test. Remember bright is dry…. Continue to drain fuel from the contaminated sump until certain the system is clear of all water…. (5). At postflight, completely fill the fuel tanks to provide an effective method against contamination from condensation. However, this procedure may be only practical on a few types of aircraft, since the type of aircraft, length of proposed flight, number of passengers, and weight and balance limitations dictate the amount of fuel to be added. 8.a.(3). A review of data in the FAA accident/incident data system revealed that some emergency landings were made in which the fuel storage system was listed as a causal factor. In many of those emergency landings, vented fuel caps were listed as a cause. The design of the vent opening allowed water to enter the fuel tanks. New types of vented fuel caps were designed for installation by the aircraft manufacturers to correct this problem. Information about these new design vented fuel caps can be found in the Aircraft Manufacturer’s Service Bulletins.

Blends of AGE-85 and 100LL Anhydrous AGE-85 and 100LL are completely blendable. Well accepted industry standard Lean the mixture for maximum power as described previously

Blends of AGE-85 and 100LL All fuels will hold water to their saturation level. Gasoline has an affinity for water. 100LL holds water. When the amount of water in the fuel exceeds the saturation level, a precipitate will form. When the amount of water in blends of AGE-85 and 100LL exceeds the alcohol component’s carrying capacity a precipitate will form.

Blends of AGE-85 and 100LL Proper pre-flight procedures will easily detect the presence of precipitated water in blends of AGE-85 and 100LL Clear and Bright Test If the sumped fuel is not clean and bright, it should not be used for flight. Hydrometer test If the specific gravity of sumped fuel is greater than 0.8, it should not be used for flight.

Blends of AGE-85 and 100LL The specific gravity of the precipitate in water contaminated blends of AGE-85 and 100LL is never below 0.8. A hydrometer easily detects the presence of water.

Blends of AGE-85 and 100LL This chart indicates that the amount of water in blends of AGE-85 and 100LL will never be larger than 11% of the AGE-85 fraction before a precipitate occurs.

Blends of AGE-85 and 100LL Scenarios (all assume no pre-flight inspection) Amount of Water Very Small Dissolved in both AGE-85 and 100LL Pure AGE-85 Completely dissolved. Engine runs smoothly. Mostly AGE-85 Completely dissolved. Engine runs smoothly. Mostly 100LL Completely dissolved. Engine runs smoothly. Pure 100LL Completely dissolved. Engine runs smoothly unless temperatures cause dissolved water to freeze. Amount of Water Small Less than 5% of solution. Pure AGE-85 Completely dissolved. Engine runs smoothly. Mostly AGE-85 Completely dissolved. Engine runs smoothly. Mostly 100LL Precipitate could form. Engine runs smoothly. Pure 100LL Precipitate formed. Engine runs smoothly until water reaches it or freezing occurs.

Blends of AGE-85 and 100LL Scenarios (all assume no pre-flight inspection) Amount of Water Large (10% of solution) Pure AGE-85 Completely dissolved. Engine runs smoothly Mostly AGE-85 Precipitate may form. Engine runs smoothly or slightly rough. Mostly 100LL Precipitate likely. Engine runs rough. Pure 100LL Precipitate formed. Engine stops (preferably prior to takeoff). Presence of AGE-85 enhances safety !