running drill right south-paws standard conversion Apply very light pressure drill restrain blade such remains un twisted drilling procedure will confine inacurracy inner less important part blade Trim off excess edges back doubler carve sand blade airfoil shape shown Fig 5 Cut piece brass bush ing reinforce hinge hole should about /i 7/16 inches length Epoxy Hot Stuff place blades can doped can covered tissue silk Ive done three ways generally use tissue Coupes dope Unlimiteds silk Wakes Hub Assembly hubs shafts use either 1/16 3/32 music wire 1/16 wire good up 14 strands Y4-in FAI rubber pretty torky stuff note Bob Whites Godfather published showing 1/16-in wire hub 16 strands Pirelli cant argue success thus far have used 3/32in wire 16 strands Bend Z hub per plans Fig 6 Bend flat twist skew angle extra bends middle part serve blade stop front blade overhung reason other Outrigger blades meet middle alleged inefficient because inner blade end tends act like additional wingtip Extending inner blade tips nearly gether should improve situation worst cant hurt Bend up shaft 900 bend about 5A inch length Take pains get near 900 possible Bind 7 hub shaft together fine iron wire about 010 inch diameter Center shaft hub closely possible Sweatsolder joint Use best rosin core solder can get finish aligning shaping hub put brass bushing back formblock insert end 7 hub shown Fig 6 Rotate hub until shaft forms 900 angle bottom block shown sketch Look also 900 angle end view Note angle other 900 correction later Remove hub insert its other end repeating checks above will able tell dihedral needs twisted 7 hub less will able tell shaft coming off Z hub correct angle Also will able tell Continued page 96 Chemical Milling powder mixed water forms acidic solution concentration easily changed addition either water powdered Ph-minus Add little powAn easy method rem Ovifl der time water mix Check THIS PROCESS simple requires method masking areas should have metal removed weak acid solution process chemical milling also contest proven safe have using FAI speed models several years have problems cracked pans although planes have hit ground hard several times have shaken apart screaming Rossi engines counterbalance one-blade prop attached engine process has numerous applications noteworthy weight conscious fliers FAI Speed Team Racing power Free Flight magnesium en gine mounts used frequently AMA speed fliers also can benefit chemical milling correcting tail heavy airplanes use heavy full pans actual process will describe applied two Darp A-size pans will used control-line World Champs models Step 1 Apply good quality masking tape areas desire have metal removed photo #1 masking tape applied area being accentuated black inked lines Pans material magnesium castings U Charles Lieber Step 2 Dip entire pan molten wax allow wax harden Photo #2 Step 3 sharp razor blade cut through wax surface pan around area marked care fully pull back masking tape area will milled should now free wax other areas should covered wax will protect acid solution photo #3 pan-i has wax stripped away area milled pan-2 still com pletely covered wax Step 4 now ready actual milling Find either glass plastic con tainer object will fit Fill enough water cover area milled go local depart ment store sells poo1 chemicals purchase some Ph-minus solid strength solution placing pan etc solution observe rate reaction bubbles fairly slow rate about right CAU TION make solution too strong will produce enough heat melt wax mask off pan ruin everything Photo #4 shows pan acid solution undergoing good reaction pan has reached desired weight thickness etc remove solution wash off dry remove wax hang pan 2000 F oven dish underneath catch wax will melt off about 10-15 minutes Photo #5 shows two pans after chemical milling removal wax slight roughness surface may noted easily removed 80 grit sandpaper photo #6 shows fin ished product Any questions concerning simple effective process can addressed Charles Lieber 725 Signal Light Road Moorestown NJ 08057 44 ModelAviation Drilling hole hinge Note restraint being applied aft edge blade Hing ing alignment always troublesome article describes procedures accuracy Photo No 1 Masking tape applied area hind engine location tape applied metal chemically milled Photo No 2 After masking tape applied magnesium piece speed model half-pans shown emersed molten wax let harden Photo No 3 Cut wax masked area carefully pull back tape expose bare mag nesium has done pan 1 left Photo No 6 finished product Roughness photo 5 removed SO grit sandpaper May1978 45 Photo No 4 Chemical milling process Bub bles show rate reaction Too fast reaction Photo No 5 Two pans after chemical milling desired since may melt wax The process leaves slight roughness
Edition: Model Aviation - 1978/05
Page Numbers: 44, 45
running drill right south-paws standard conversion Apply very light pressure drill restrain blade such remains un twisted drilling procedure will confine inacurracy inner less important part blade Trim off excess edges back doubler carve sand blade airfoil shape shown Fig 5 Cut piece brass bush ing reinforce hinge hole should about /i 7/16 inches length Epoxy Hot Stuff place blades can doped can covered tissue silk Ive done three ways generally use tissue Coupes dope Unlimiteds silk Wakes Hub Assembly hubs shafts use either 1/16 3/32 music wire 1/16 wire good up 14 strands Y4-in FAI rubber pretty torky stuff note Bob Whites Godfather published showing 1/16-in wire hub 16 strands Pirelli cant argue success thus far have used 3/32in wire 16 strands Bend Z hub per plans Fig 6 Bend flat twist skew angle extra bends middle part serve blade stop front blade overhung reason other Outrigger blades meet middle alleged inefficient because inner blade end tends act like additional wingtip Extending inner blade tips nearly gether should improve situation worst cant hurt Bend up shaft 900 bend about 5A inch length Take pains get near 900 possible Bind 7 hub shaft together fine iron wire about 010 inch diameter Center shaft hub closely possible Sweatsolder joint Use best rosin core solder can get finish aligning shaping hub put brass bushing back formblock insert end 7 hub shown Fig 6 Rotate hub until shaft forms 900 angle bottom block shown sketch Look also 900 angle end view Note angle other 900 correction later Remove hub insert its other end repeating checks above will able tell dihedral needs twisted 7 hub less will able tell shaft coming off Z hub correct angle Also will able tell Continued page 96 Chemical Milling powder mixed water forms acidic solution concentration easily changed addition either water powdered Ph-minus Add little powAn easy method rem Ovifl der time water mix Check THIS PROCESS simple requires method masking areas should have metal removed weak acid solution process chemical milling also contest proven safe have using FAI speed models several years have problems cracked pans although planes have hit ground hard several times have shaken apart screaming Rossi engines counterbalance one-blade prop attached engine process has numerous applications noteworthy weight conscious fliers FAI Speed Team Racing power Free Flight magnesium en gine mounts used frequently AMA speed fliers also can benefit chemical milling correcting tail heavy airplanes use heavy full pans actual process will describe applied two Darp A-size pans will used control-line World Champs models Step 1 Apply good quality masking tape areas desire have metal removed photo #1 masking tape applied area being accentuated black inked lines Pans material magnesium castings U Charles Lieber Step 2 Dip entire pan molten wax allow wax harden Photo #2 Step 3 sharp razor blade cut through wax surface pan around area marked care fully pull back masking tape area will milled should now free wax other areas should covered wax will protect acid solution photo #3 pan-i has wax stripped away area milled pan-2 still com pletely covered wax Step 4 now ready actual milling Find either glass plastic con tainer object will fit Fill enough water cover area milled go local depart ment store sells poo1 chemicals purchase some Ph-minus solid strength solution placing pan etc solution observe rate reaction bubbles fairly slow rate about right CAU TION make solution too strong will produce enough heat melt wax mask off pan ruin everything Photo #4 shows pan acid solution undergoing good reaction pan has reached desired weight thickness etc remove solution wash off dry remove wax hang pan 2000 F oven dish underneath catch wax will melt off about 10-15 minutes Photo #5 shows two pans after chemical milling removal wax slight roughness surface may noted easily removed 80 grit sandpaper photo #6 shows fin ished product Any questions concerning simple effective process can addressed Charles Lieber 725 Signal Light Road Moorestown NJ 08057 44 ModelAviation Drilling hole hinge Note restraint being applied aft edge blade Hing ing alignment always troublesome article describes procedures accuracy Photo No 1 Masking tape applied area hind engine location tape applied metal chemically milled Photo No 2 After masking tape applied magnesium piece speed model half-pans shown emersed molten wax let harden Photo No 3 Cut wax masked area carefully pull back tape expose bare mag nesium has done pan 1 left Photo No 6 finished product Roughness photo 5 removed SO grit sandpaper May1978 45 Photo No 4 Chemical milling process Bub bles show rate reaction Too fast reaction Photo No 5 Two pans after chemical milling desired since may melt wax The process leaves slight roughness