Control Line: Speed

CONTROL LINE SPEED SEVERAL INDIVIDUALS have written information reasonably priced 21-size engines control line Speed sport flying Unadvertised almost unknown control line version K&B 21 engine designed small ducted-fan RC modelsa true ABC Schnuerle-ported ball-bearing-supported crankshaft rear drum valve neat little power plant shown photoIt modified Sportster engine built like other well known K&B racing engines 58 75 cc has brass chrome plated sleeve special contour-ground piston designed high rpm interested call factory directI dont think distributors handle 2100 College Dr Lake Havasu City AZ 864031 havent chance run yet Ill report rpm performance K&B also has new glow plug called KB iL HP high performance has thicker rugged different alloy element couple columns ago expounded techniques necessary make own engines Curbs Aloise FABS team has done also promised explain model building procedures Bob Fogg F FABS team uses create carbon-fiber/epoxy airplanes fly Curbs makes engines aluminum speed pan Bob builds models Bob has built fiberglass/epoxy models Rat Racing several years now uses carbon-fiber cloth stiffer stronger lighter assemblies has improved construction design model built now follows procedure something like usually begins machining wing form good pine wood six-axis computer-controlled milling machine six-axis control means milling table can rotate pivot roll commands Bob types computer tell servo motors what plots airfoil shape desired prints table input necessary cuts milling machine will take mounts pine board table punches data machine moves proper position mill takes cut step repeated times until has exact form top half desired wing shape needs half because makes fiberglass mold master form wing will have symmetrical airfoil make mold wood master sanded finished perfection mold release applied layers glass cloth glass mat epoxy formed around master make stiff strong permanent mold carbon cloth shell can cast After epoxy sets up mold has cured mounted large aluminum plate keep everything straight good mold release applied carbon cloth put place epoxy mix brushed cloth assembly put vacuum bag air pumped out excess epoxy squeegeed out edges want minimum weight soit crucial get out much epoxy possible epoxy has strong brittle Bob uses Shell 815 special hardener strength called TETA Now pay attention ever attempt use TETA make sure read Material Safety Data Sheet MSDS follow safety precautions nasty stuff must use adequate ventilation properly filtered breathing masks proper gloves goggles proper clothing handling Dont ever try bypass safety recommendations using epoxies will get Some epoxies especially hardeners can burn blind poison dont mess around using After curing half-shell placed vacuum holding fixture also made master pattern vacuum fixture has bunch holes grooves connected vacuum pump air pressure holds thin shell exactly right edges can sanded centerline twice have two wing halves can glued foam core core made Rohacell foam machined just like pine master except both sides finished thin layer glue applied two half shells placed foam core three additional narrow layers style 1120 carbon cloth weave bias added leading edge entire assembly vacuum-bagged curing Essentially same procedure used make stabilizer tailboom engine cowl carbon-fiber cloth little chopped glass necessary fill tight corners extra layers carbon cloth used additional strength stiffness required FABS team also makes its own propellers carbon fibers carbon cloth wrote give idea much precision work FABS team does reach its championship standing isnt easy dont learn overnight also impossible us really want apply enough effort Model Aviation ersion K&B 21 shown available 21 Sport Speed other small control line modelssee text Bob Fogg FABS Speed Team works record-setting Class D sidewinder model 1994 Nats Santo Rizzotto Brockton MA has ardent Speed fan years Shown Indianapolis meet last summer