SPAD Devestator Building Instructions


The Dynamo is our first €œbudget€  entry into RCCA legal B open class combat competition. The prototype was  equipped with a ThunderTiger® Pro .25„’, a 4 oz. fuel tank, and a standard sized  Futaba® flight pack. All Coroplast® parts are made from 4mm Coroplast®. It  weighed in at 3.45 lbs. Slightly heavy compared to some of the current planes  used in competition, but an excellent way to get involved for a minimum amount  of money. Flight performance is outstanding, and will provide any pilot a good  entry level plane with which to €œget in the mix€.


The fuselage is cut from a 24€  section of 2 ½€ O.D. PVC gutterpipe as shown on the fuselage drawing. A butane  or propane torch is used to heat and bend in the wing saddle rails, and bend out  the tail cradles. We fabricated a 1€ wood block to fit the inside dimensions of  the gutterpipe with which to bend the wing saddle rails inward against. There is  no down or right thrust in the Dynamo fuselage. Two Ό€ x 4 ½€ long dowels are  used for the wing rubber band hold downs. Coat them with CA to fuel proof them,  and hold them in place. The firewall is fabricated from ½€ plywood to the I.D.  of the gutterpipe, and is installed flush with the forward edge of the fuselage.  The fuel tank is mounted on a 4€ yardstick tray glued to the back of the  firewall. A slot cut into the firewall to receive the fuel tank tray will help  strengthen this assembly. Make sure the fuel tank tray will clear the forward  wing hold down dowel! Mount the firewall to the fuselage with 4 #6 x Ύ€ self  tapping screws. Mount the engine as high on the firewall as possible for the  best €œthrust line€. This will aid in nice clean axial rolls! Drill a small hole  in the aft fuselage for combat streamer attachment!


You have two choices to use for  your Dynamo wing. The wing shown in the wing drawing was used on the prototype.  It is constructed from one piece of Coroplast® with the flutes running in the  spanwise direction. A 36€ standard yardstick is used for the spar, with four 1€  pieces of yardstick used for spar supports, as shown on the drawing. The  ailerons are hinged simply by cutting away one side of the Coroplast® flute! For  a more rigid wing, with the flutes running in the chordwise direction, simply  build a Dominator wing, as all chordwise dimensions are the same. Just cut it  down to a 36€ span! Use the Dynamo spar configuration, and please note that the  wing center reinforcement is used only on the top to save weight. We leave the  wing tips open, also to save weight. €œFlame€ the plastic and use medium CA for  all glue areas. USE SMALL 1/8" DROPS EVERY INCH OR SO.  A  BEAD OF GLUE MAY NOT WORK! USING TOO MUCH GLUE IS THE BIGGEST MISTAKE  HERE!  Cut a hole just aft of the spar for a snug aileron servo fit, with  the ears of the servo resting on the plastic. Secure the servo in place using a  zip-tie, and zip-tie doubler as shown in the drawing. Fabricate aileron control  horns from scrap PVC, and glue in place. Flame the horns and ailerons before  gluing! This is VERY important, as we don€™t use screws or backplates to save  weight! Cut a small hole in the bottom of the wing aft of the servo for the  aileron servo lead to pass through.


The Dynamo tail is cut from a 20€  x 7€ piece of Coroplast® as shown in the tail drawing. Score and fold the center  section as shown on the drawing, and hinge the elevators by cutting away one  side of the Coroplast® flutes. Fabricate two elevator control horns from scrap  PVC. Glue the horns in place, and glue the tail to the fuselage using medium CA.  Flame the tail, horns, and fuselage before gluing!  This is VERY important, as  we are not using backplates, doublers, or screws to save  weight!

Radio  Installation:

The elevator and throttle servo  are stuck in place using double sided foam mounting tape, drill a hole on each  side of the servo, then secure using zip-ties as shown in the radio installation  drawing. The battery and receiver are simply stuck in place using double sided  foam mounting tape. Use the battery positioning to achieve the proper CG. Your  Dynamo should balance level at the forward top spar line!  Slightly nose heavy  is OK, tail heavy is UNACCEPTABLEandDANGEROUS!  Your antenna can be routed up through the tail  by poking a small hole in a Coroplast® flute near the base of the tail. Mount  your switch where convenient along the side of the fuselage. Fabricate a  €œwishbone€ pushrod for your elevators, and rig your ailerons and elevators to  your satisfaction. The Dynamo ailerons are very responsive, so be ready for it!   The nature of a V-tail makes the elevators less responsive than a conventional  elevator, so they can be rigged with a considerable amount of  throw!

NOTE: When  rigging your ailerons, ensure that the bottom of the ailerons are parallel to  the top of the fuselage!  Do not allow then to droop (like flaps)!   If your  ailerons droop, they will drastically affect pitch  trim!

Flying the  Dynamo:

Make sure your throttle is rigged  to shut your engine OFF for landing, and your prop is €œclocked€ to stop in the  horizontal position. ALWAYS FOLLOW ALL AMA SAFETY RULES AND  REGULATIONS! If you plan to enter an RCCA sanctioned combat event (open  class B), weigh your Dynamo to assure that it falls under the 3.5 lb. weight  limit. Mount your wing with at least 12 (6 per side) #64 rubber bands! The  ThunderTiger® Pro .25„’ was plenty of power for our Dynamo prototype, and at full  throttle, it climbed out perfectly with a slight hand launch. The Dynamo will  perform any maneuver a combat pilot could desire, and float in for a gentle dead  stick landing after engine shutdown.  If your enemies are balsa or foam, they  better hope they don€™t get in your way!  IF YOU ARE NEW TO  COMBAT, AND HAVE NOT FLOWN THIS TYPE OF AIRCRAFT BEFORE, PLEASE ENLIST THE HELP  OF A QUALIFIED INSTRUCTOR!  It is also highly recommended that you add  some bold graphics to the top of your wing for in flight  orientation!

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