I Scale 0 Bob Dolly Wischer EXPERIMENTAL Aircraft Association members number years have building planes reduced-size ver sions military aircraft problems scaling down similar en countered modelers Ben Owen EAA headquarters staff also AMA modeler has summarized scaling tech-Dave Gregware great crowd pleaser last Nets tast maneuverable Lockheed nique followsLightning P-38 Sport Scale twin powered K&B 40s equipped Du-Bro mufflers lated fully loaded condition model constructed NASA Standard3/4 Scale1/2 Scale1/4 Scalespecial interest us modeled after typical low-wing single-engine light general-aviation type plane gross weight 1500 pounds size span 59 length 46 Continued page 89 SCALING AIRPLANES USING 1-FT-SO CUBE AS EXAMPLE Uimensimn Linear Area square foot Volume cubic foot weight ace Area Cube sq ft What proves shows different reductions measure ment scaling convenience engi neers have historically used linear meas urement scaling fact linear reduction mean ht volume should clearly kept mind Examples Fermula 1 Airplane Length 16 ft Wing area 66 sq ft Weight empty 500 lbs Sabre Jet F-SI Length 31 ft Wing area 2879 sq ft Weight 10000 lbs 1/4 scale model 4 ft 4125 sq ft 594 sq 781 lbs 1/2 scale airplane 185 ft 71975 sq ft 1250 lbs would appear scale modeling home-built aircraft too different helps explain prize winning potential custom-built planes designed constructed modelers par ticularly may have scale oriented good example Steen Skybolt former scale modeler Hale Wallace has trophies both sizes planes Using scale models stall/spin testing Another interesting aspect scale model ing use radio-controlled planes design testing techniques stall spin evaluation general-aviation air craft Several years ago paper sub ject written Sanger M Burk NASA Calvin F Wilson Piper Air craft described develop ment relatively inexpensive radiocontrolled model stall/spin test method 75525 562 9/16251/4062 1/16 42221/641251/801561/64 3315 5625%15 25%315 625% operational experiences NASA Piper utilizing technique apparent narration modelers have fortunate re covery spins advanced stalls due largely light wing loadings An 8-lb 1A-scale model could weigh much 14 16 pounds still fly spin recovery would likely marginal An inadvertent spin snap roll incipient spin has spelled end fine over weight scale craft tests described parachute used insure spin recovery chute must open arrest spin jettisoned soon recovery complete plane can continue flight single servo actuates both func tions may appear person can handle in fact two pilots required pilot operates rudder ailerons parachute other controls elevator flaps throttle 16-lb plane accurately simu 22 Model Aviation 1 foot 1 sq ft 1 Cu ft 6 sq ft Slick Lockheed Sirius Sport Scale Sob Gumi foyle has slick finish Super Poxy over fiberglass fuselage Foam base wing balsa fiberglass K&B 60 pumper own muffler Art Scholls Chipmunk modeled Bob Wilde achieved extremely fine finish Super Poxyall authentic lettering done decals press-on type Ship modified Stafford kit powered K&B 61 engine Bob spent 45 hours squeezing hand-made muffler feet show specimen have need flyable engine because guts oldies practically non-existent would like arrange trade write Don Jenkins 2915 E 65th St Indiana polis IN 46220 letter Dick Phillips sent Prince George British Columbia contained what Dick called Fun Fly idea #476B Place Dixie cup model ala bomb drop contestant issued ten jelly beans navy beans lima beans smarties whatever areRVP placed cup prescribed series maneuvers flown example Takeoff Figure Eight Approach Land K-Factor func tion maneuvers times number beans still cup contestants score series maneuvers can related pilots skill level Im still lookout good Fun Fly ideas about sharing yours rest us Ron Van Pune 12 Connie Dr Shah mar FL 32S79 RC Scale/Wischers continued page 22 freon actuated retracts very similar average scale planes plane dif fered average respect values moment inertia about roll pitch axis reduced special construction techniques change important us would like avoid unexpected surprise spin low level snap roll Light strong construc tion especially near tail wing tips essential element model fuselage laminates fiberglass cloth impregnated resin wings balsa covered fiber glass resin weight kept mini mum squeezing laminates molding process because resin con tributes little strength Tail s4rfaces wing tips made balsa free-foam ing plastic light weight Ballast added place center gravity desired location bring weight up desired 16 pounds engine test model stand ard 61 completely cowled scale planes same problem encoun tered us similar situations overheated answer would control airflow through ducts baffling NASA engineers chose dif ferent approach added large heat sink engine consisted four large circular aluminum fins attached tightly cylinder Because spin tests would permit large center gravity excursions fuel tank lo cated CG pressure system regulator employed interesting aspects tests telemetry method returned information ground means seven-channel model type transmitter case board plane re layed signals seven sensors measur ing angle attack side slip control positions hobby receiver ground servos operating potentiometers recording oscillograph Another technique has used modelers should used ten practice utilizing second plane similarly loaded gain experience before flying plane may have taken years build Start tests practice plane loaded lightly add weight until heavy finished scale model will pilots used method good effect since landing speed creased greatly during time weight being increased found run way 1000 feet long 100 feet wide required Piper tests conducted twin 60-powered /6-scale 15-lb plane righthand Supertigre engine modified rotating front bearing give opposite rotation tests also em ployed two pilots spin recovery chute Like NASA plane fiber glass fuselage two layers cloth nose wing trailing edge layer tail polyurethane foam wing core covered 3/32 balsa fin ished fiberglass cloth epoxy resin retract gear powered dessi January1978 89 cated compressed air rather usual freon because tests run winter temperatures down 15 degrees F Some interesting facts useful model ers gleaned paper proper rotation lift-off main gear centers must /4 3/ behind CG ground angle attack should set two degrees nose-up ease lift-off protection nose gear Gear collapses caused shattering four sets hand-carved maple props half lefthand requiring 40 minutes carving time two engineers flew Piper model well quali fied recreational radio-control model fliers speed characteristics model new experience gained needed familiarity heavy plane progressively adding weight practice plastic-and-foam ARF until loaded up 2 times its design weight Some useful hints twin-engine flying included notes Asymmetrical power during spins throttle open wider caused autorotation rates twice normal spin rate results flat spin rate descent reduced spins can induced unequal throttle settings idle retreating engine tends quit due reverse air flow over prop twin-engine plane spins after failure engine close other throttle quickly open again after recovery dive plane has retracted landing gear dont extend until near touchdown reduce drag modelers would perform intentional spins twin accidental spin twin last Lake Charles Nats concluded crash could possibly have avoided Bob Wischer Rt 1 S-221 Lapham Peak Rd Delafield W1S3018 Foam/Evans/Lester continued page 27 adhesives first test coating foam scraps Sources Foam Expanded Bead Polystyrene FoamGen eral Sources independent manufacturers some will sell directly club purchase suffi cient quantity Otherwise can direct dealers sell foam density interested typically 1-1 cu ft Both manufacturers retailers may found yellow pages under PlasticsFoam Beadboard insulation common forms usable modeler typically available 1 lb/cu ft density thicknesses 2 some times 3 building materials sup pliers carry material also widely used aquatic applications typic ally molded 15 pcf density name nearest supplier can obtained writing Arco Polymers Inc Philadel phiaPA 19101 Custom cutting cores done some hobbyists local RC club good place start looking Styrofoam Extruded Polystyrene Foam styrofoam manufactured Dow Chemical Company its licensees Styro foam SM Sheathing Material widely available type suitable air craft modelers ranges 18 20 pcf available through building material suppliers 4X8-ft sheets thicknesses 1 1 2 sometimes 3 Look Dow Chemical yel low pages under Plastics write Dow Chemical USA Midland MI 48640 continued First Last/Aycock continued page 31 ing P-47 Thunderbolt will finished same flew Europe capable design work can attested author has flown original bipe very fine performer fighter Bills comment need trainer want looks like airplane atti tude outlook man first American Ace World War II Acknowledgment The author would like thank Lt Col Dunn assist ance supplying records photographs 90 Model Aviation GEE BEE RACER 1/32 SCALE PLASTIC MODEL KIT CONSTRUCT R-1 OR 1-2 ALSO SEPARATELY WASP SEND 5Ot FOR COMPLETE ILLUSTRATED CATALOG DEPT MA PAWNEE ST SAN MARCOS CA 9 Another Sport Scale entry Riverside David Lovitts Blackburn Land-Sea Monoplane Note laminated prop Covered Coverite powered K&B 40 Slim Line muffler
Edition: Model Aviation - 1978/01
Page Numbers: 22, 89, 90
I Scale 0 Bob Dolly Wischer EXPERIMENTAL Aircraft Association members number years have building planes reduced-size ver sions military aircraft problems scaling down similar en countered modelers Ben Owen EAA headquarters staff also AMA modeler has summarized scaling tech-Dave Gregware great crowd pleaser last Nets tast maneuverable Lockheed nique followsLightning P-38 Sport Scale twin powered K&B 40s equipped Du-Bro mufflers lated fully loaded condition model constructed NASA Standard3/4 Scale1/2 Scale1/4 Scalespecial interest us modeled after typical low-wing single-engine light general-aviation type plane gross weight 1500 pounds size span 59 length 46 Continued page 89 SCALING AIRPLANES USING 1-FT-SO CUBE AS EXAMPLE Uimensimn Linear Area square foot Volume cubic foot weight ace Area Cube sq ft What proves shows different reductions measure ment scaling convenience engi neers have historically used linear meas urement scaling fact linear reduction mean ht volume should clearly kept mind Examples Fermula 1 Airplane Length 16 ft Wing area 66 sq ft Weight empty 500 lbs Sabre Jet F-SI Length 31 ft Wing area 2879 sq ft Weight 10000 lbs 1/4 scale model 4 ft 4125 sq ft 594 sq 781 lbs 1/2 scale airplane 185 ft 71975 sq ft 1250 lbs would appear scale modeling home-built aircraft too different helps explain prize winning potential custom-built planes designed constructed modelers par ticularly may have scale oriented good example Steen Skybolt former scale modeler Hale Wallace has trophies both sizes planes Using scale models stall/spin testing Another interesting aspect scale model ing use radio-controlled planes design testing techniques stall spin evaluation general-aviation air craft Several years ago paper sub ject written Sanger M Burk NASA Calvin F Wilson Piper Air craft described develop ment relatively inexpensive radiocontrolled model stall/spin test method 75525 562 9/16251/4062 1/16 42221/641251/801561/64 3315 5625%15 25%315 625% operational experiences NASA Piper utilizing technique apparent narration modelers have fortunate re covery spins advanced stalls due largely light wing loadings An 8-lb 1A-scale model could weigh much 14 16 pounds still fly spin recovery would likely marginal An inadvertent spin snap roll incipient spin has spelled end fine over weight scale craft tests described parachute used insure spin recovery chute must open arrest spin jettisoned soon recovery complete plane can continue flight single servo actuates both func tions may appear person can handle in fact two pilots required pilot operates rudder ailerons parachute other controls elevator flaps throttle 16-lb plane accurately simu 22 Model Aviation 1 foot 1 sq ft 1 Cu ft 6 sq ft Slick Lockheed Sirius Sport Scale Sob Gumi foyle has slick finish Super Poxy over fiberglass fuselage Foam base wing balsa fiberglass K&B 60 pumper own muffler Art Scholls Chipmunk modeled Bob Wilde achieved extremely fine finish Super Poxyall authentic lettering done decals press-on type Ship modified Stafford kit powered K&B 61 engine Bob spent 45 hours squeezing hand-made muffler feet show specimen have need flyable engine because guts oldies practically non-existent would like arrange trade write Don Jenkins 2915 E 65th St Indiana polis IN 46220 letter Dick Phillips sent Prince George British Columbia contained what Dick called Fun Fly idea #476B Place Dixie cup model ala bomb drop contestant issued ten jelly beans navy beans lima beans smarties whatever areRVP placed cup prescribed series maneuvers flown example Takeoff Figure Eight Approach Land K-Factor func tion maneuvers times number beans still cup contestants score series maneuvers can related pilots skill level Im still lookout good Fun Fly ideas about sharing yours rest us Ron Van Pune 12 Connie Dr Shah mar FL 32S79 RC Scale/Wischers continued page 22 freon actuated retracts very similar average scale planes plane dif fered average respect values moment inertia about roll pitch axis reduced special construction techniques change important us would like avoid unexpected surprise spin low level snap roll Light strong construc tion especially near tail wing tips essential element model fuselage laminates fiberglass cloth impregnated resin wings balsa covered fiber glass resin weight kept mini mum squeezing laminates molding process because resin con tributes little strength Tail s4rfaces wing tips made balsa free-foam ing plastic light weight Ballast added place center gravity desired location bring weight up desired 16 pounds engine test model stand ard 61 completely cowled scale planes same problem encoun tered us similar situations overheated answer would control airflow through ducts baffling NASA engineers chose dif ferent approach added large heat sink engine consisted four large circular aluminum fins attached tightly cylinder Because spin tests would permit large center gravity excursions fuel tank lo cated CG pressure system regulator employed interesting aspects tests telemetry method returned information ground means seven-channel model type transmitter case board plane re layed signals seven sensors measur ing angle attack side slip control positions hobby receiver ground servos operating potentiometers recording oscillograph Another technique has used modelers should used ten practice utilizing second plane similarly loaded gain experience before flying plane may have taken years build Start tests practice plane loaded lightly add weight until heavy finished scale model will pilots used method good effect since landing speed creased greatly during time weight being increased found run way 1000 feet long 100 feet wide required Piper tests conducted twin 60-powered /6-scale 15-lb plane righthand Supertigre engine modified rotating front bearing give opposite rotation tests also em ployed two pilots spin recovery chute Like NASA plane fiber glass fuselage two layers cloth nose wing trailing edge layer tail polyurethane foam wing core covered 3/32 balsa fin ished fiberglass cloth epoxy resin retract gear powered dessi January1978 89 cated compressed air rather usual freon because tests run winter temperatures down 15 degrees F Some interesting facts useful model ers gleaned paper proper rotation lift-off main gear centers must /4 3/ behind CG ground angle attack should set two degrees nose-up ease lift-off protection nose gear Gear collapses caused shattering four sets hand-carved maple props half lefthand requiring 40 minutes carving time two engineers flew Piper model well quali fied recreational radio-control model fliers speed characteristics model new experience gained needed familiarity heavy plane progressively adding weight practice plastic-and-foam ARF until loaded up 2 times its design weight Some useful hints twin-engine flying included notes Asymmetrical power during spins throttle open wider caused autorotation rates twice normal spin rate results flat spin rate descent reduced spins can induced unequal throttle settings idle retreating engine tends quit due reverse air flow over prop twin-engine plane spins after failure engine close other throttle quickly open again after recovery dive plane has retracted landing gear dont extend until near touchdown reduce drag modelers would perform intentional spins twin accidental spin twin last Lake Charles Nats concluded crash could possibly have avoided Bob Wischer Rt 1 S-221 Lapham Peak Rd Delafield W1S3018 Foam/Evans/Lester continued page 27 adhesives first test coating foam scraps Sources Foam Expanded Bead Polystyrene FoamGen eral Sources independent manufacturers some will sell directly club purchase suffi cient quantity Otherwise can direct dealers sell foam density interested typically 1-1 cu ft Both manufacturers retailers may found yellow pages under PlasticsFoam Beadboard insulation common forms usable modeler typically available 1 lb/cu ft density thicknesses 2 some times 3 building materials sup pliers carry material also widely used aquatic applications typic ally molded 15 pcf density name nearest supplier can obtained writing Arco Polymers Inc Philadel phiaPA 19101 Custom cutting cores done some hobbyists local RC club good place start looking Styrofoam Extruded Polystyrene Foam styrofoam manufactured Dow Chemical Company its licensees Styro foam SM Sheathing Material widely available type suitable air craft modelers ranges 18 20 pcf available through building material suppliers 4X8-ft sheets thicknesses 1 1 2 sometimes 3 Look Dow Chemical yel low pages under Plastics write Dow Chemical USA Midland MI 48640 continued First Last/Aycock continued page 31 ing P-47 Thunderbolt will finished same flew Europe capable design work can attested author has flown original bipe very fine performer fighter Bills comment need trainer want looks like airplane atti tude outlook man first American Ace World War II Acknowledgment The author would like thank Lt Col Dunn assist ance supplying records photographs 90 Model Aviation GEE BEE RACER 1/32 SCALE PLASTIC MODEL KIT CONSTRUCT R-1 OR 1-2 ALSO SEPARATELY WASP SEND 5Ot FOR COMPLETE ILLUSTRATED CATALOG DEPT MA PAWNEE ST SAN MARCOS CA 9 Another Sport Scale entry Riverside David Lovitts Blackburn Land-Sea Monoplane Note laminated prop Covered Coverite powered K&B 40 Slim Line muffler
Edition: Model Aviation - 1978/01
Page Numbers: 22, 89, 90
I Scale 0 Bob Dolly Wischer EXPERIMENTAL Aircraft Association members number years have building planes reduced-size ver sions military aircraft problems scaling down similar en countered modelers Ben Owen EAA headquarters staff also AMA modeler has summarized scaling tech-Dave Gregware great crowd pleaser last Nets tast maneuverable Lockheed nique followsLightning P-38 Sport Scale twin powered K&B 40s equipped Du-Bro mufflers lated fully loaded condition model constructed NASA Standard3/4 Scale1/2 Scale1/4 Scalespecial interest us modeled after typical low-wing single-engine light general-aviation type plane gross weight 1500 pounds size span 59 length 46 Continued page 89 SCALING AIRPLANES USING 1-FT-SO CUBE AS EXAMPLE Uimensimn Linear Area square foot Volume cubic foot weight ace Area Cube sq ft What proves shows different reductions measure ment scaling convenience engi neers have historically used linear meas urement scaling fact linear reduction mean ht volume should clearly kept mind Examples Fermula 1 Airplane Length 16 ft Wing area 66 sq ft Weight empty 500 lbs Sabre Jet F-SI Length 31 ft Wing area 2879 sq ft Weight 10000 lbs 1/4 scale model 4 ft 4125 sq ft 594 sq 781 lbs 1/2 scale airplane 185 ft 71975 sq ft 1250 lbs would appear scale modeling home-built aircraft too different helps explain prize winning potential custom-built planes designed constructed modelers par ticularly may have scale oriented good example Steen Skybolt former scale modeler Hale Wallace has trophies both sizes planes Using scale models stall/spin testing Another interesting aspect scale model ing use radio-controlled planes design testing techniques stall spin evaluation general-aviation air craft Several years ago paper sub ject written Sanger M Burk NASA Calvin F Wilson Piper Air craft described develop ment relatively inexpensive radiocontrolled model stall/spin test method 75525 562 9/16251/4062 1/16 42221/641251/801561/64 3315 5625%15 25%315 625% operational experiences NASA Piper utilizing technique apparent narration modelers have fortunate re covery spins advanced stalls due largely light wing loadings An 8-lb 1A-scale model could weigh much 14 16 pounds still fly spin recovery would likely marginal An inadvertent spin snap roll incipient spin has spelled end fine over weight scale craft tests described parachute used insure spin recovery chute must open arrest spin jettisoned soon recovery complete plane can continue flight single servo actuates both func tions may appear person can handle in fact two pilots required pilot operates rudder ailerons parachute other controls elevator flaps throttle 16-lb plane accurately simu 22 Model Aviation 1 foot 1 sq ft 1 Cu ft 6 sq ft Slick Lockheed Sirius Sport Scale Sob Gumi foyle has slick finish Super Poxy over fiberglass fuselage Foam base wing balsa fiberglass K&B 60 pumper own muffler Art Scholls Chipmunk modeled Bob Wilde achieved extremely fine finish Super Poxyall authentic lettering done decals press-on type Ship modified Stafford kit powered K&B 61 engine Bob spent 45 hours squeezing hand-made muffler feet show specimen have need flyable engine because guts oldies practically non-existent would like arrange trade write Don Jenkins 2915 E 65th St Indiana polis IN 46220 letter Dick Phillips sent Prince George British Columbia contained what Dick called Fun Fly idea #476B Place Dixie cup model ala bomb drop contestant issued ten jelly beans navy beans lima beans smarties whatever areRVP placed cup prescribed series maneuvers flown example Takeoff Figure Eight Approach Land K-Factor func tion maneuvers times number beans still cup contestants score series maneuvers can related pilots skill level Im still lookout good Fun Fly ideas about sharing yours rest us Ron Van Pune 12 Connie Dr Shah mar FL 32S79 RC Scale/Wischers continued page 22 freon actuated retracts very similar average scale planes plane dif fered average respect values moment inertia about roll pitch axis reduced special construction techniques change important us would like avoid unexpected surprise spin low level snap roll Light strong construc tion especially near tail wing tips essential element model fuselage laminates fiberglass cloth impregnated resin wings balsa covered fiber glass resin weight kept mini mum squeezing laminates molding process because resin con tributes little strength Tail s4rfaces wing tips made balsa free-foam ing plastic light weight Ballast added place center gravity desired location bring weight up desired 16 pounds engine test model stand ard 61 completely cowled scale planes same problem encoun tered us similar situations overheated answer would control airflow through ducts baffling NASA engineers chose dif ferent approach added large heat sink engine consisted four large circular aluminum fins attached tightly cylinder Because spin tests would permit large center gravity excursions fuel tank lo cated CG pressure system regulator employed interesting aspects tests telemetry method returned information ground means seven-channel model type transmitter case board plane re layed signals seven sensors measur ing angle attack side slip control positions hobby receiver ground servos operating potentiometers recording oscillograph Another technique has used modelers should used ten practice utilizing second plane similarly loaded gain experience before flying plane may have taken years build Start tests practice plane loaded lightly add weight until heavy finished scale model will pilots used method good effect since landing speed creased greatly during time weight being increased found run way 1000 feet long 100 feet wide required Piper tests conducted twin 60-powered /6-scale 15-lb plane righthand Supertigre engine modified rotating front bearing give opposite rotation tests also em ployed two pilots spin recovery chute Like NASA plane fiber glass fuselage two layers cloth nose wing trailing edge layer tail polyurethane foam wing core covered 3/32 balsa fin ished fiberglass cloth epoxy resin retract gear powered dessi January1978 89 cated compressed air rather usual freon because tests run winter temperatures down 15 degrees F Some interesting facts useful model ers gleaned paper proper rotation lift-off main gear centers must /4 3/ behind CG ground angle attack should set two degrees nose-up ease lift-off protection nose gear Gear collapses caused shattering four sets hand-carved maple props half lefthand requiring 40 minutes carving time two engineers flew Piper model well quali fied recreational radio-control model fliers speed characteristics model new experience gained needed familiarity heavy plane progressively adding weight practice plastic-and-foam ARF until loaded up 2 times its design weight Some useful hints twin-engine flying included notes Asymmetrical power during spins throttle open wider caused autorotation rates twice normal spin rate results flat spin rate descent reduced spins can induced unequal throttle settings idle retreating engine tends quit due reverse air flow over prop twin-engine plane spins after failure engine close other throttle quickly open again after recovery dive plane has retracted landing gear dont extend until near touchdown reduce drag modelers would perform intentional spins twin accidental spin twin last Lake Charles Nats concluded crash could possibly have avoided Bob Wischer Rt 1 S-221 Lapham Peak Rd Delafield W1S3018 Foam/Evans/Lester continued page 27 adhesives first test coating foam scraps Sources Foam Expanded Bead Polystyrene FoamGen eral Sources independent manufacturers some will sell directly club purchase suffi cient quantity Otherwise can direct dealers sell foam density interested typically 1-1 cu ft Both manufacturers retailers may found yellow pages under PlasticsFoam Beadboard insulation common forms usable modeler typically available 1 lb/cu ft density thicknesses 2 some times 3 building materials sup pliers carry material also widely used aquatic applications typic ally molded 15 pcf density name nearest supplier can obtained writing Arco Polymers Inc Philadel phiaPA 19101 Custom cutting cores done some hobbyists local RC club good place start looking Styrofoam Extruded Polystyrene Foam styrofoam manufactured Dow Chemical Company its licensees Styro foam SM Sheathing Material widely available type suitable air craft modelers ranges 18 20 pcf available through building material suppliers 4X8-ft sheets thicknesses 1 1 2 sometimes 3 Look Dow Chemical yel low pages under Plastics write Dow Chemical USA Midland MI 48640 continued First Last/Aycock continued page 31 ing P-47 Thunderbolt will finished same flew Europe capable design work can attested author has flown original bipe very fine performer fighter Bills comment need trainer want looks like airplane atti tude outlook man first American Ace World War II Acknowledgment The author would like thank Lt Col Dunn assist ance supplying records photographs 90 Model Aviation GEE BEE RACER 1/32 SCALE PLASTIC MODEL KIT CONSTRUCT R-1 OR 1-2 ALSO SEPARATELY WASP SEND 5Ot FOR COMPLETE ILLUSTRATED CATALOG DEPT MA PAWNEE ST SAN MARCOS CA 9 Another Sport Scale entry Riverside David Lovitts Blackburn Land-Sea Monoplane Note laminated prop Covered Coverite powered K&B 40 Slim Line muffler