Owners Manual - Hangar 603

Oil consumption pre the Warner Engine Handbook is nominally 0.025 lb / hp / hr at max power and 0.020 lb / hp / hr at cruise. This gives a consumption of 0.39 gallon per hour at cruise. Fuel Type: 100 LL aviation gas with 2 oz Marvel Mystery Oil (MMO) mixed per 5 gallons of gas. (The MMO is recommended for protection of the valves guides while running—unavoidably--at lead contents / octane well above that for which this engine was designed.) (Auto gas has been recommended in lieu of aviation fuel, but that was before ethanol was added to auto fuel on a wide-spread basis. The alcohol is more detrimental to the engine and components than the higher lead content / octane according to antique engine experts.) Consumption (per Warner Engine Handbook): 8.1 gph @ 1700 RPM 13.4 gph @ 2050 RPM Engine The current engine is a Warner Super Scarab SS-50 Serial Number 693 of 145 hp. (There is a “Repair and Alteration Form for installation of a Warner SS-50 on another Waco RNF, but the one for N11259 is not available as of this writing (28 Nov 2008). Pressure (Warner Engine Handbook) Oil pressure should be a minimum 50 psi for operations and should not exceed 90 psi. Idle oil pressure of 40 psi is an acceptable minimum. Temperatures Cylinder Head Temperature Maximum cylinder head temperature is 525 0 F (according to Warner Engine Handbook p. 17) at rear plug, 300 0 F at cylinder base, lee side of cylinder barrel. Using instrument reading in cockpit 7 CHT is to be kept below 400 0 F according to Al Holloway. The Warner Engine Manual says not to take off with CHT below 120 0 F but the CHT gauge cannot be programmed below 200 0 F, so that value was used for minimum operating temperature on the gauge. Oil Temperature Minimum oil temperature is 80 0F. Maximum oil temperature is 200 0 F at the engine inlet. (Warner Engine Handbook, p. 17) (The oil temperature sensor on N11259 is at the bottom of the external oil tank in the area from which the pressure pump draws.) Performance3 Engine Speeds • RPM idle = 600 (nominal) • RPM max power = 2050 • RPM max = 2150 • PRM cruise = 1800 Power • Maximum power output is 145 hp at 2050 rpm • The maximum permissible cruising power rating of this engine, when using a fixed propeller is 109 h.p. at 1865 rpm Rate of Climb Initial Rate of Climb: 925 fpm claimed with 125 hp Warner (800 fpm quoted for 110 hp Warner) Actual = ~500 fpm for first two thousand feet experienced during flights for PMA of new pistons with 145 hp Warner Takeoff Distance • Normal = <Specification not found>; Actual = <TBD> • 50 Ft Object (Actual) - <TBD> Landing Distance • Normal = 235 ft (no brakes) (Grass?); Actual = <TBD> • 50 Ft Object (Actual) - <TBD> Service Ceiling 14,500 ft 3 Numbers in blue are from Sport Flying Vol. 3, No. 4, April 1969, “Identifying Waco Airplanes”, for “NF” type fuselage and wings (no engine specified.) 8 Speeds • Vs = 50 mph indicated • Vx = ~75 mph indicated • Vy = • Vne = 108 mph • Vcruise = 92 mph claimed with 125 hp Warner (95 with 110 hp Warner per AAF4) At 90% power cruise is about 85 mph indicated with the 145 hp Warner installed) • Vtop = 108 mph (112 mph per AAF) • Vland = 41 mph 4 Arizona Aircraft Foundation 9 System and Component Descriptions This section attempts to document N11259 systems and components. Some components have documentation, but much of the integration of systems and performance of integrated systems is not documented. There is more detail in the following where it was necessary to get the overall systems functioning correctly. Airframe The airframe includes the fuselage, wings, empennage, flying wires, and (included because they are accessed at least once a year) inspection covers. The landing gear is discussed separately in the next section. Fuselage The fuselage is welded steel tubing faired longitudinally with wood strips and with a wooden turtle deck from aft of the rear cockpit to the rudder. Sheet aluminum fairs the rudder / stabilizer area, the cockpits, and a streamlined headrest on top of the turtle deck. The following four photos show the fuselage in various stages of restoration. 10 During restoration, all steel was stripped and recoated with epoxy primer. All new wood and aluminum was used. Wood parts were coated with Poly Fiber EV-410 epoxy varnish. Aluminum cowling around the cockpits is held down with #8-32 screws that go into threaded barrels glued in the wood fairings on the cockpit longerons and in the formers in front of and behind the cockpits. The seats have lap belt restraints only, no shoulder restraints. Engine Mount and Cowl The engine mount was changed from the original at the time the engine was upgraded to the Warner Super Scarab-50 145 hp. At the time of this writing (Dec 2008) there was no Form 337 paperwork accounting for this change. A form 337 for upgrade of the engine of another RNF shows a motor mount different than on N11259. In addition, the motor mounts on two other know RNFs belonging to Susan Theodorelos are also different than that on N11259. The motor mount on N11259 was implicitly certified when the aircraft was recertified after restoration. The motor mount on N11259 is a steel tube structure welded (not bolted) to the front of the fuselage. The motor mounts to a ring supported by six tubes, two each side from the upper longerons and one each side from the center of the bottom front fuselage cross tube. The ring has ten lugs formed of 1” long tubing with washers welded to each end. Each lug is positioned to correspond to one of the ten mounting holes on the back of the Warner SS-50 engine. The following photos show the motor mount. 11 In the second photo, attach tabs can be seen. The engine is mounted to the mount ring with rubber bushings illustrated in the following diagram and photos. The rubber bushing is from ESTCO Enterprises, 1549 Simpson Way Escondido, CA 92029. A 4130 sleeve was fitted to the motor mount lugs to accommodate the rubber bushing more precisely. The sleeve was coated with room temperature vulcanization rubber before insertion. The rubber bushings insert back-to-back but require a spacer between their bottoms to make the stem expand as the mount bolt is tightened. In addition, the bushings were slightly undersize for the tubes on the engine mount, so insert tubing was used to make the fit snug. 0.67 1.25 1.08 0.35 0.25 0.31 (5/16") Mounting Lug Rubber Bushings Washers 0.13 (23/64") 1.02 (1-1/64") (1/8") ESTCO Part No E3375 1-1/64 (1.020) 41/64 (0.638) 5/16 (0.313) 39/64 (0.606) 1 / 4 (0.250) 23/64 (0.346) 0.64 0.38 0.38 3/8" 0.67 Buna-A A five-piece cowl covers the back of the engine compartment. 12 There is a nose bowl that bolts to the front of the Warner SS-50 and has “fingers” that extend back between cylinders #1, 2, 3, 5, 6, and 7. (The carburetor protrudes between cylinders #4 and #5 precluding a finger there. Each finger in the cowl front piece has a hole for a bolt that attaches to corresponding fingers in the cowl top and two cowl side pieces. A bottom cowl piece is a reinforced aluminum plate that extends from the firewall to the bottom of the cowl ring mount. A top cowl piece extends from the firewall forward to the cowl mount ring. The top piece has a hole for the oil tank filler cap and two “fingers” in the front that attach to the cowl front piece on each side of cylinder #1. Bolt holes in the fingers on the cowl top piece mate with corresponding bolt holes in the fingers of the cowl front piece. These holes align with nut plates on the cowl mount ring that accept #10-32 stainless steel truss head screws. The cowl top piece has Screw holes along each side for mount of the cowl side pieces. The cowl top piece has mounting holes along the back edge that mate with nut plates on the firewall flange that accept #10-32 stainless steel truss head screws. There are two cowl side pieces. Each side piece extends from the firewall forward to the cowl mount ring. Each side piece has two fingers that mate with and slip under fingers from the cowl front piece; the right side cowl has fingers either side of cylinder #3 and the left side either side of cylinder #6. Holes in the side piece fingers mate to holes in the front piece fingers and then mate with nut plates on the cowl mount ring that accept #10-32 stainless steel truss head screws The side pieces slip under the cowl top piece and have holes that mate with holes along the edge of the cowl top piece. The side pieces have nut plates imbedded behind this row of holes that accept #10-32 stainless steel truss head screws. The cowl side pieces also have holes along the back side that mate with holes in the firewall flange through stand-off stubs backed by nut plates that accept #10-32 stainless steel truss head screws of varying length. The stand-offs provide space at the rear between the side cowls and the fuselage sides for escape of cooling air for the oil tank. There are also holes along the bottom edge of the side cowls that mate with holes in the cowl bottom piece where nut plates are attached to the reinforcing channel along each side of the bottom piece. These nut plates accept #10-32 stainless steel truss head screws. The original RNF cowl was formed from aluminum. During reconstruction, Jack recreated the nose bowl and top cowl using foam molds over the engine components and five layers of S-glass and epoxy for the cowl material. The side and bottom cowlings are made from aluminum. Nylon washers are used under all cowl mounting screws to protect the paint and cowl material. All cowl mount screws are stainless steel which tends to gall with recurrent use. All screw threads should be treated with anti-seize compound before use to prevent galling. (The same anti-seize compound used for the spark plugs is used for the stainless steel screw threads.) The original RNF did not have screws holding the cowl together. It had studs in the top and bottom cowl pieces that protruded through holes in the side cowl pieces. The studs had holes for pins that were inserted after the side pieces were installed over the studs and a wire keeper threaded through the holes in the studs to retain the cowl side pieces. Jack didn’t understand the original cowl retention configuration and adopted the screws and nut plates instead. 13 Wings The RNF wings are wood with a fore and aft spar, a spar along the aileron hinge line, and an aluminum leading edge from forward spar top to bottom. Ribs are wooden trusses with plywood gussets. The wing is braced against fore and aft forces by drag and anti-drag wires attached to the spars and tightened by turnbuckles. At the points on the spars where the drag / anti-drag wires attach there are steel tube compression bars that support the forces of the tightened wires (except for the outer-most attach point where a wood compression strut is used.) The trailing edge is aluminum bent in a “V” shape. During restoration, every spar, rib, and other wood component was scraped and / or sanded smooth. Every gusset was tested for attach strength and all those that failed test were replaced. All loose or inferior glue joints were restored with T-88 epoxy. The restored wood structure was coated with PolyFiber EV-400 epoxy varnish. All metal fittings (wing / fuselage attachments, compression struts, cross-brace attachments, flying wire attachments, strut attachments, aileron pushrods and bellcranks) were stripped, primed with epoxy primer and coated with silver Alumigrip. The leading edge aluminum was coated with PolyFiber epoxy primer. The lower wing has plywood covering from the root rib to the second rib. That plywood had to be replaced in places and was increased in thickness slightly. Hand holds were molded into the lower wing tips per original practice for the float version of the RNF. 14 The wing center section had to be completely reconstructed. The basic parts created for that reconstruction are shown in the following photo. The center section has cross-brace wires at the bottom of the airfoil (to allow space for the gas tanks) and an aluminum leading edge from front spar top to bottom. The trailing edge is a curved “V” section piece of aluminum. At the aft ends of the center section, there are molded and reinforced wooden hand-holds to aid the pilot in entry to the aft cockpit. Two gas tanks are contained in the center section. They are suspended between the fore and aft spars by attachments that capture stainless steel straps that surround the tanks (padded by thick fabric). The top center section is covered by an aluminum sheet attached to the spars and end ribs by #10-32 screws into nut plates attached under caps on the ribs and the spars. The ailerons are wood structures. A typical photo is shown below prior to restoration (lower right aileron). 15 Empennage The fin, rudder, horizontal stabilizer and elevator are all welded steel structures. All steel was stripped to metal and refinished with epoxy primer before covering. Covering All covering followed the Poly Fiber process exclusively using Poly Fiber cloth attached with Poly Tac and coated with Poly Brush which is also used for attachment and initial coating of protective tapes. All flying surfaces were rib-stitched with areas where sheeting precluded top- to-bottom stitching stitched to attached members before the occluding side was covered. After coating with Ploy Spray silver ultraviolet protection, the flying surfaces were painted with Juneau White and the fuselage and rudder with Bahama Blue. Poly Tone paint was used on fabric surfaces; Aero-Thane paint was used on metal and composite surfaces Flying Wires Flying wires were purchased from Steen Aero Lab, 1451 Clearmont Street NE, Palm Bay, FL 32905, (321) 725-4160. Steen orders the wires from Bruntons Aero Products, Ltd in England (formerly McWhite.) The exact wires ordered are in the Appendices to this Owner’s Manual They were installed using information from the Waco Type “F” Instruction Manual and verbal information from other biplane restorers. The Waco Instruction Manual is accessible via the following PDF icon. 16 Waco Model F Instruction Manual Aileron Gap Seals The gap between the wing and aileron is significant because of the size of the hinges used. In flight air leaks from the (higher pressure) lower surface to the (lower pressure) upper surface of the wing through the wing / aileron gap and significantly reduces aileron effectiveness— especially in the lower speed landing configuration. In order to prevent loss of control during low speed operations, the wing / aileron gap needs to be sealed. There are a number of ways to accomplish this but the means selected for this plane was to use 3” propeller tape with a 1” or 1 ½” smooth (white duct or packing) tape along it’s middle. White is used to make the seal seem more aesthetically pleasing. The following figure illustrates the tape used to seal the gaps. The following picture of a gap seal in place is taken looking down the wing / aileron gap from the wing tip. Inspection Covers There are 51 inspection covers on the RNF that need to be removed for annual inspection in addition to the side cowl pieces. They include the following. (Not included is the aluminum fairing between the rudder and stabilizer; that area can be inspected through the hole for 17 stabilizer trim motion and the inspection plate on the bottom of the fuselage in that area. The rear stabilizer fairing can be removed if necessary.) • Six round covers on the bottom of each lower wing these are at the compression strut and anti-drag cable fittings on the spars and wing-fuselage attach brackets on the spar • An aileron bell crank cover and a round cover on the aileron at the control horn (each wing) • Four round covers on the bottom of each upper wing where the compression struts and anti-drag cables attach to the spars • Four rectangular covers on the top inboard of each upper wing that cover the • Three rectangular plates on the bottom of the fuselage from the motor mount back behind the landing gear that show landing gear attachments, antenna attachments, and some of the Johnson Bar brake cabling. • One round cover on the bottom of the fuselage at the tail that shows stabilizer attachment (in addition to that visible through the stabilizer / fuselage fairing • Two covers under the fuselage at each forward lower wing spar attach point. (The rear spar attach points are visible from inside the rear cockpit.) • One bubble cover under the fuselage port side that exposes a pulley of the Johnson Bar brake system There are additional covers at the point where the flying and landing wires attach to the wings. Whether these need to be removed for annual is up to IA discretion. There is more discussion and documentation of inspection covers in the maintenance addendum to this owner’s manual. See this imbedded file. Waco RNF N11259 Inspection Covers Landing Gear The landing gear includes the main gear, tailwheel, and brakes. General Configuration The RNF landing gear is a tail wheel configuration. The main gear is an outrigger type with oleo struts. The brakes are mechanical actuated by a “Johnson Bar” lever described below. The original tailwheel on the RNF was a free-castoring wheel mounted under the fuselage even with the stabilizer leading edge as shown in the pre-restoration photo below. 18 In the interests of safety, Jack replaced this tailwheel with a modern Maule tailwheel mounted at the tail post of the fuselage during restoration. The tailwheel mounting configuration copied the practice of other planes (like a piper cub) in attaching the Maule tailwheel to the fuselage. Main Gear Design The main landing gear mounts on braced outrigger struts just behind the firewall. The wheels are suspended on oleo struts from the outriggers. The oleo struts pivot at the axle and are braced by fore and aft struts welded to the axle and hinged at the fuselage center. These lower brace struts are faired with balsa wood to an airfoil shape and wrapped in Ceconite for strength. The wheels are supported on axles of stepped-down dimensions as shown in the following photo. 19 (On some RNFs the oleo struts are enclosed in an aluminum airfoil-shaped fairing. Reportedly, this fairing also encloses a safety cable that connects the axle with the outrigger. The safety cable is to preclude the wheels from dropping out of the oleos should there be a failure of the oleo struts. At the time of this writing, those safety cables are not installed on N11259.) The wheels and brakes are Aircraft Products Corporation Model 650-10. Tires Tires are Specialty Tire of America (STA) 2.80/2.50 x 4, 4 ply nylon inflated to 23 lbs. They need to be balanced on the wheels. The wheels are not well balanced and if left that way, the heavy side rotates to the bottom during flight and the bottom becomes the same place scuffed upon landing every time. It doesn’t take too long to scuff through to the cords. Balancing avoids that and distributes the scuffing around the tire. Maintenance Brake adjustment is detailed in the Waco Model F Instruction Manual. The oleo struts use brake fluid. The amount and the check and fill process are also detailed in the Waco Model F Instruction Manual. The tires and wheel are relatively heavy as aircraft tires go. They do not need to be balanced for running but they do need to be balanced to preclude bald spots. If the tire / wheel combination is not balance, the tire will rotate to a heavy side low position in the air and that spot on the tire will be scuffed on each landing. It doesn’t take long for a flat spot to develop and threaten to go into the tire cord. It takes up to 4.5 oz of weight to static balance a wheel / tire combination. 20 Tail Wheel Design The tailwheel is a Maule Model SFSP8A1-2, Part Number TW-100. Installation instructions and a blow-up diagram of components is in the appendices to this Owner’s Manual and accessible via the PDF icon. Maule Tailwheel Installation Instructions Some shimmy was experienced during touchdown. The tailwheel was shimmed so that the kingpin pivot axis of the tailwheel is back at the top and forward toward the bottom. (This is referred to as a negative kingpin angle.) Spring tension between the tailwheel control horn and the control arms on the rudder is barely taught (with no tension). There is more information on tailwheel shimmy in the appendices to this Owner’s Manual and is accessible via the PDF icon. Tail Wheel Shimmy The primary condition to preclude shimmy is the negative kingpin angle, but the extent of that angle has to be modulated to ensure steering is stable. With a negative kingpin angle the height of the tail decreases as the tailwheel rotates from straight back. That creates a condition of increasing stability when tailwheel turns. The tailwheel wants to reverse and the only thing that prevents that is tension in the kingpin that keeps the tailwheel locked and steerable by the rudder pedals. If the kingpin angle to too negative, the tailwheel will unlock easily and the plane becomes very difficult to steer. It is likely that this condition would promote much easier ground-looping, too. Tailwheel springs are the compression type meaning that they are initially extended and when the rudder pedal is used to pull on the rudder horn for steering, the spring is put in compression. There are those who argue compression springs are bad because, if they bottom out, they impart significant force on the rudder horn with the potential for damage. On the Maule tailwheel unit, the compression stroke is long and bottoming is unlikely. In addition, the tailwheel should unlock before any damage occurs. The tailwheel is held on to the fuselage with a square tubing cross piece between the lower two longerons. That square tubing has a bushing in the middle where the bolt holding the front of the tailwheel leaf spring is attached so that tightening that bolt will not crush the tubing. The aft 21 portion of the tailwheel leaf spring is bolted to the tailpost with two bolts through a plate that goes under the springs. The attaché point on the fuselage is a fitting similar to what is used on Univaire tailwheel mounts on Cubs and other planes. Maintenance The tailwheel needs to be inspected annually to ensure the kingpin angle remains negative in spite of possible spring wear / fatigue. The kingpin should be greased annually. Tailwheel inflation should be maintained at 65 lbs/ sq in. Brakes Design The brakes are drum type and are manually actuated by a cable that runs from the throttle lever in each cockpit to the brake lever on the wheels. On the way to the brake lever, the cable passes around a pulley on an arm off the bottom of the rudder pedals. These pulleys change the pressure applied to each brake in such a manner that braking is increased in the direction of applied rudder; brake application is not independent of rudder application as in modern aircraft. Mechanical Linkages The following photo shows the way the cable comes off of the throttle arm on the left side of the cockpit when the throttle arm is rotated inboard. In the photo, white cord has been used to check the cable path during restoration. The white cord shows up better than the actual cable and thus photos with cord are used here for illustration. 22 The cable proceeds from the pulley shown above to a pulley at the bottom of the left side of the fuselage and from there around the pulley on the bottom of the rudder pedal. From the bottom of the rudder pedal, the cable goes around a pulley near bottom fuselage center and then travels down the landing gear strut. Note the following picture is looking up at the bottom of the u covered fuselage. Throttle arm Brake arm pivot Throttle pivot Brake cable (simulated) Brake cable pulley Brake cable from upper pulley Rudder pedal Lower brake cable pulley Rudder pedal brake cable pulley Rudder pedal pivot point Brake cable pulley at top of landing gear strut 23 At the base of the landing gear strut, the brake cable goes around yet another pulley to gain position to apply leverage on the brake actuation arm attached to the wheel. The following photo shows the inside of the brake. The brake actuation arm is not shown, but goes on the far side of the brake shoes as shown in the photo. The actuation arm operates an elliptical cam inside the joint shown on the right in the picture. When the lever is actuated, the wide part of the cam forces the shoes apart and applies the brake. On the opposite end of the shoes are two short metal pieces that meet at an angle and are pivoted from a bolt that extends through the back of the brake plate through a radial slot. If the pivot bolt is moved in or out in the radial slot, it expands or retracts the shoes and that is how the brakes are adjusted in Upper brake cable pulley Lower brake cable pulley Rudder pedal brake cable pulley Lower center fuselage brake cable Landing gear strut Brake cable 24 accordance with the process described in the Waco Model F Instruction Manual. There is a nut on the pivot bolt and a slot in the end of the pivot bolt that protrudes from the back of the brake plate. There is no need to remove the wheel to adjust the brakes; the bolt and nut are accessible from the back of the brake plate as shown in the second picture. Actuator The brake actuator is the throttle lever. Brakes are applied by tilting the throttle lever inboard. Note that the brakes are not strong enough to hold the plane when the engine is run above 1200 RPM. Maintenance The brakes are to be adjusted as needed. The adjustment procedure is described in the Waco Model F Instruction Manual. Power System It is useful to be acquainted with radial engines in general when looking at the Warner in particular. General information on radial engines from “Aircraft Engine Maintenance for the Engine Mechanic” by Brimm and Boggess is contained via the following PDF icon. “Aircraft Engine Maintenance”, Brimm and Boggess 25 Engine The engine in N11259 is a Warner Super Scarab 145 hp, Serial Number SS693E. It has an enclosed valve rocker, manually greased. Overview of the Warner Super Scarab is contained in the Warner Engine Handbook. That handbook can be accessed by double-clicking the following PDF icon. (Illustrated) Warner Engine Handbook There are references care and operation of Warner engines obtained from the web. They are in an Appendix to this Owner’s Manual. (Note that one reference applies to a 165 hp Warner, but that information is useful by analogy.) The following components are integral to the Warner engine and are discussed in the Warner Engine Handbook. They are included here because they are important to engine hookup and integration in to the airframe and / or maintenance during operation. Oil Pump There are two oil pumps, a primary pressure pump that pumps oil from the tank into the engine for lubrication and a second scavenger pump that sucks oil out of the sump and pumps it back into the external oil tank. 26 Rocker Arms The rocker arms have to be manually greased. Zerk fittings are provided on each rocker arm to accomplish this. According to Al Holloway, he uses about ten strokes of a manual grease gun 27 per zerk on similar engines, but it is best to remove the rocker arm covers and observe when the grease just starts to come out of the rocker arm pivot bearings. The grease used is Chevron Ultra Duty Grease EP NLGI 2. Air Intake and Carburetor Heat The carburetor has a cover that includes a valve which can select air delivery to the carburetor from outside air or from air that has passed through a heat muff. The valve is controlled from a [black] push/pull knob in the rear cockpit (right side) via a Bowden cable. The carburetor air intake cover has an opening rearward (in addition to the hot air intake port) to exhaust hot air from the heat muff when that air is not selected. The heat muff is formed around the exhaust pipe where the ring converges for a single pipe outlet. The muff has holes in front at the bottom and a single large hole in the back at the top. In theory, air entering the front holes is heated as it passes over the section of exhaust pipe before exiting to the carburetor air intake. There is a CEET hose delivering the exiting air from the heat muff to the rear of the air intake where it can go to the carburetor when the air intake valve is switched to select heated air. 28 There is about 50-75 RPM drop when the carb heat is applied at full power. The carburetor air intake is between the two bottom engine cylinders immediately in front of the carburetor. Cold air enters directly into the air intake housing through a relatively coarse mesh screen. Cold air or hot air is selected by control of a butterfly valve inside the air intake housing. When cold air is selected the hot air is vented through a port in the bottom of the air intake housing. The butterfly valve for cold or hot air selection is controlled by the carburetor heat knob on the lower right side of the aft cockpit (only). It is attached to a Bowden cable that runs to a bell 29 crank that, in turn, moves the butterfly valve. The black control knob can be seen in the cockpit photo above. The bellcrank and control cable are shown below. Exhaust The exhaust is a stainless steel collector ring fabricated by Aircraft Exhaust Systems, Inc. of Jumping Branch, WV. That firm has since gone out of business and assets have reportedly been transferred to Acorn Welding (Acorn Welding Ltd., 10916-119 Street, Edmonton, Alberta, Canada, T5H 3P4, Phone: 1-888-388-8803 or 1-780-447-5955, sales@acornwelding.com). The exhaust ring is a series of pieces that slip-fit one into the next from cylinder #6 clockwise (from the cockpit) to cylinder #4. Cylinder #5 has a separate short section that joins with the ring formed by sections from #6 - #4 to make a common single exhaust portion pointing straight down from to below the air intake. The heat shroud that produced air for carburetor heat surrounds this common down-pipe. 30 Propeller and Shaft Propeller is a Falcon wooden propeller Model Designation Tc-800, D-627A, Serial Number 30. Propeller diameter is 84”; pitch is 67”.5 The propeller hub consists of a front and back flange with cylindrical protrusion through the propeller hub that is an integral part of the rear flange. The front flange can be seen in the above photo for the exhaust system as the silver disk bolted to the propeller. Front and back flanges are bolted to the prop with 3/8”-24 bolts and nuts. They are torqued to 175-225 in-lbs. The front flange is also secured with a nut that screws over the front portion of the rear flange cylindrical protrusion. (This is not visible in the above photo; it is obscured by the brass colored prop nut. 5 Other RNF owners with Warner Super Scarab engines report using 86” x 67” and 86” x 63” props. 31 The propeller shaft is the forward part of the Warner crankshaft. It is a tapered shaft with a key in it. The inside of the rear flange cylindrical protrusion has a mating keyway that keeps the propeller from slipping on the shaft. The propeller hub fits against tight on the propeller shaft held in place by the brass propeller nut. Both the nut on the rear flange cylindrical protrusion and the prop nut are held in place with cylindrical clips A special wrench was made by Matt Hlavac and used on the unique propeller nuts because previous use by (apparently) spanner wrenches had significantly marred the nuts. The special wrench is shown below. 32 Magnetos Magnetos are Scintilla VMN-7D type with a base pad mount that, in turn, mounts to the engine pad forged on the back of the Warner SS50. The magnetos were rebuilt during the second Warner overhaul and are now configured with parts from various old magnetos. Correct magneto installation and timing procedure is document further in this section of the owner’s manual and is based on information and demonstration by Al Holloway, Holloway Engineering, Inc., 262 Spanish Creek Rd., Quincy, CA, 95971, (530) 283-2500, www.radialengine.com . The following pictures show the magnetos as install, left first, then right. 33 General information on engine magnetos is available from web information included in an appendix to this Owner’s Manual. An Operation, Service, and Overhaul Instruction Manual for the Scintilla VMN-7 magneto family is also in the addendum to this Waco RNF N11259 Owner’s Manual. Spare parts have been obtained from Harmon Dickerson [(573) 449-6428, hdaircraft@hotmail.com , 3657 Ben Williams Rd, Columbia, MO 65201] and Gene Augustine [Augustine Magneto Parts Co. (818) 399-1904, 2416 West Victory, Burbank, Ca 91506]. An Alternate source is Savage Magneto Service [(510) 782-7081, 2415 Radley Court #7, Hayward, CA 94544]. Installation The magnetos are base mounted on brackets cantilevered from the back of the Warner engine accessory case. The brackets are shown in the first photo below; the magneto mounted on the bracket and coupled to the magneto drive extending from the back of the accessory case is shown in the second photo. 34 They are driven from rotary drive shafts protruding from the back of the Warner accessory case (The two round holes in the picture above) which are terminated in annular rings that have a series of attach holes around the annulus. The drive ring from the back of the engine mates with the magneto ring as shown in the following pictures. Both magnetos are driven clockwise looking at the driven end of the magneto. The uniqueness of these rings are that the hole pattern is such that if the two rings—the one from the engine and the one on the magneto—are put together, there will be two opposing holes that will line up within 1-2°. This becomes important when setting the magneto up for timing. 35 The challenge mounting the fixed-base magneto to the engine drive is that perfect alignment is virtually impossible and so a flexible drive arrangement is made. Description of this flexible drive refers to the following picture. The magneto has a cross arm on its output shaft. The magneto ring that mates with the engine drive ring has two opposing studs. The magneto mating ring is attached to the magneto cross arm via a flexible rubber annulus made of ¼” conveyer belt-like material reinforced with fiber chords. The material was obtained from Restoration Supply Company (RSC) of Escondido (15182-B Highland Valley Rd., Escondido, CA 92025, (800) 306-7008). The coupling was cut from the material with masking tape temporarily on its surface to provide drawing surface for the part. The magneto cross arm and mating ring attach to the flexible coupling 90° from each other and the intervening space allows flex to correct for any slight misalignment. This allows the magneto to be set correctly for timing and then mated to the engine drive ring after the engine is also set correctly for timing. 36 Spark Plug Leads At the time of this writing (Aug 2008), the spark plug leads are shielded with stainless braid from just above magneto phenolic resin block to the spark plug. An aluminum cover made by Al Holloway clamps the lead braid to make a closed, grounded attachment for the leads to the top of the magneto. Looking from the back of the magneto, spark plug wires attach to the phenolic blocks according to firing order (not cylinder) number. Firing order to cylinder number correlation is in a table in the Warner Engine Handbook, Section 5, “Ignition Harness Assembly”. The number for each spark plug wire is embossed on the phenolic blocks. Firing numbers 1,5,6,7 are on the left half phenolic block and firing numbers 2,3,4 are on the right half. Firing order is 1, 3, 5, 7, 2, 4, 6. 37 Engine Ignition Timing The Warner Super Scarab Engine Handbook (WSSEH) says to set Magneto timing to 28 0 before top dead center when using a timing light. Timing is determined by the points opening (degrees before piston reaches top dead center) on number one cylinder. The following process was used to get the Warner in the right configuration for magneto mating follows: 1. Determine when #1 cylinder is top dead center on compression stroke. First remove all front plugs on the engine. Remove the valve covers on #1 cylinder and observe when the intake valve closes indicating that the next stroke would be the compression stroke. Hold a thumb over the empty spark plug hole on #1 cylinder and feel when that cylinder is compressing indicating the piston is on the way up. 2. A “TimeRite” instrument was used to determine when the cylinder was TDC. The tool screws into the front spark plug hole and has a probe that reaches in to contact the top of the rising cylinder. The probe pivots on the back of the instrument and the opposite end indicates on the front of the instrument when the piston has reached TDC and is starting back down. (The process is complicated by the fact that the propeller blade can strike the tool as installed in the front spark plug hole for the #1 cylinder and so the blade has to be past the tool when the tool is installed, yet with the piston far enough down to still allow the tool with probe to be inserted. Had the propeller been installed such that TDC occurred with the blade past the tool and the required advance point been with the prop blade before the tool, the tool could not be used. The WSSEH assumes the propeller is off the engine during timing.) 3. Once TDC is located, there is a slide indicator on the TimeRite which is used to record the TDC point of the probe. A scale calibrated for the Warner 145 HP engine is then moved so that it is “zero-referenced” to TDC. The propeller is backed off and the slide indicator moved to the proper number of degrees before TDC for firing—in this case 280. The propeller can then be advanced until the probe meets the slide indicator at which time the piston is positioned where the magneto points should be opening to fire the cylinder. In addition, there is a homemade tool that attaches over the front propeller flange. The tool has a protractor and a free-moving pointer that is weighted at the bottom. (The tool is fabricated from a large coffee can that fits snugly over the prop flange and provided the base for this tool. The plastic coffee can lid can be rotated on the can--it’s placed on the bottom in the figure--and taped in place when positioned. It’s crude looking, but accurate and easy to install and remove.) 38 4. The tool is attached at TDC and the protractor shifted until the pointer points to zero at TDC. The propeller can then be backed off to an indicated 28 0 BTDC for #1 cylinder. 5. A “Magneto Synchronizer” tool is used to determine that the magnetos are firing when required and that they fire together in synchronism. The synchronizer is attached to ground and left and right magneto leads are attached to the “P” lead to the corresponding magnetos. When setting the magneto timing, the left and right lead can be attached to the magneto P-lead circuit physically since the magneto will be uncovered. This instrument is used to validate the magneto timing; if the magnetos are out of time, the process described below has to be followed. If testing the timing after the magneto is covered, it is convenient to attach to the “P” lead using a special homemade adapter shown in the following picture. It slips into the tubing the P-lead inserts into and can be installed with the capacitor in place. 39 6. If the synchronizer shows a magneto to be out of time, its timing can be adjusted, but the process requires that the magneto be decoupled from the engine to do so. The process is explained in the following section on magneto synchronization. Magneto Timing and Synchronization The magnetos are automatically synchronized when individually timed using the described procedure Magneto installation has been described above including the flexible coupling and mating drive rings, engine and magneto. When timing the magneto, the engine is placed in position to fire #1 cylinder as described above. The magneto is also set to fire #1 cylinder and the two are coupled together via opposing bolts in the mating drive rings. The Warner Engine Handbook and magneto manual (see below for PDF version) describe how the magneto is rotated to the point where it is about to fire #1 cylinder by matching markings on the inside magneto case and the geared disk just inside it at the front. (Note that the advance lever should be fully clockwise for normal operation when looking from the back of the magneto.) When a magneto synchronizer is set up, each magneto fires when the synchronizer lights and buzzer go out. Using this method avoids opening the magneto. 40 The engine rotary drive ring and the magneto drive ring each have a pattern of holes around their circumference. (See the picture of the magneto drive ring below.) When the magneto is aligned and installed on its base and the engine is positioned to the proper number of degrees BTDC for firing #1 cylinder, one set of the holes (180 0 apart in the rings) will line up so bolts can be inserted. (This is the alignment procedure.) In my case, one magneto ended up 10 early (e.g., 270) and the other 1 0 late (e.g. 29 0). This procedure is a LOT easier to describe than perform because the bolts that are inserted to hold the two rings together go in from the front where access is limited and well into the overall obstructions of oil and fuel lines, control rods, etc. that congest the area around and behind the magnetos. Once the timing is established and the bolts in, they still have to be safety wired in that constrained environment. (It is best not to have small children within earshot when this procedure is being performed.) This procedure is easier if the engine-to-oil tank oil return line is first removed at the engine providing more clearance to get a hand and wrench on the bolts holding the drive ring to the magneto ring. The following picture shows the engine port where the return oil line has been disconnected and one bolt partially removed.