Descon Cutlass

Scratch - Cutlass {Scratch}

Contributed by Kelo Waivio

Manufacturer: Scratch
(Contributed - by Kelo Waivio)
Cutlass 

Trans-Orbital Interceptor

T' Cutlass be inspired by t' Star Fury fighters from t' Babylon 5 Sci-Fi series. Avast, me proud beauty! Avast, me hearties, me proud beauty! I liked t' look o' the Star Fury, with t' engines out on t' end o' t' "wings". I also found a use for those paper tubes that come with t' Copper head ignitors. Begad! I was also pretty happy with t' way t' cockpit canopy turned out. 

{short description of image}

Main fuselage parts list:
BT60 body tube or equivalent. Blimey! Blimey! Avast, me proud beauty! Blimey! 18" lg.
BT50 body tube or equivalent, me hearties, me bucko, 3" lg.
Paper centerin' rings, BT60-50 size, ya bilge rat, shiver me timbers, 3 pieces.
.035" music wire or standard Estes type engine hook
1/8" launch lug 3" lg.
1/8" launch lug 1" lg.
1/32" (100 lb. Begad! test) Keelhaul®©™® cord, shiver me timbers, ya bilge rat, 18 t' 20" lg.
1/8" elastic shock cord 36" lg.
18" parachute and snap swivel. Arrr! (I used a rip-stop nylon chute)
PNC60 from Estes nose cone pack. T' one that's 4 5/8" long from tip t' shoulder.
Plastic protective cap from stick deodorant (Right Guard)
3/16" square basswood or spruce strip 4 1/4" lg. cut at 45 degrees at one end.
3/16" square basswood or spruce strip 2" lg. Aye aye! Cut at 45 degrees at one end.
1/8" x 3/8" basswood or spruce strip 12" long cut at 45 degrees one end, 2 pieces.
1/8" square basswood or spruce strip, 3" long, 1 piece and 1" long, 1 piece.
Plastic cover guard from disposable razor (A Bic disposable I think)
3/32" thick spruce or basswood sheet for fins.
1/8" square basswood or spruce strip for fin root fairings.
Fin Pattern

{short description of image}

Engine pod parts list:
BT20 body tubes or equivalent, me hearties, arrr, 4" lg. Avast! Begad! 4 pieces.
Centerin' rings Totally Tubular CR5-20 (13mm x 18mm)
18mm tube couplin' Totally Tubular CPL-20, ya bilge rat, cut into 1/2" long sections
4 wire nuts, me hearties, (12 gauge size I think, arrr, t' yellow ones)
Copper Head ignitor tubes, me hearties, me bucko, cut into 1" long sections. Well, blow me down! Total o' 28 pieces.
3/16" square basswood or spruce strips 2" long cut at 45 degrees each end. Begad! Blimey! 8 pieces.

T' Cutlass started out with a shorter 9-inch body tube, but it soon became apparent that I would need an unacceptable amount o' nose weight. I added another 9-inch section o' tube so t' final model would use a stock section of Estes BT60. Ahoy! Blimey! Avast! Blimey! T' motor mount is pretty standard modroc construction. Begad! Blimey! Avast, shiver me timbers, me proud beauty! Blimey! I used a length o' Apogee light Keelhaul®©™® attached t' t' end o' t' motor mount tube and tied off with a loop at t' open end o' t' body tube. Ya scallywag! Blimey! I used an engine hook made o' .035 inch music wire. Begad! Blimey! Avast, me proud beauty! Blimey! I bent t' hook long enough so t' forward bend would catch t' forward end o' the motor block. This lets t' motor block absorb any ejection force rather than t' thin wall o' t' body tube. 

I had t' add split shot sinkers t' t' nose cone, but initially I was guessin' at where t' CP would probably be. Aye aye! Blimey! Blimey! Blimey! Blimey! Blimey! I dropped split shot into t' tip o' t' cone and secured them with hot melt. Blimey! Blimey! Well, blow me down! Blimey! Blimey! Blimey! I have t' CG with a C6-3 motor and flight ready at approximately 7 inches from t' aft o' t' model. 

In t' end t' Cutlass came out way heavier than I figured on. Avast! (I could have used balsa on this model but I have been usin' basswood more often for modroc construction.)  Without paint or motor it weighed in at 145 grams. Begad! This is a bit beyond t' recommended maximum lift off weight o' C motors. Arrr! I launched it for t' first time on a C6-3. It boosted nice and straight with apogee around 150 feet. Blimey! Ejection occurred about 1 second past apogee. Avast, me proud beauty! I launched it again on a C5-3 with similar results. Blimey! Begad! I will either rebuild this model with a 24mm motor mount or restrict it t' 18mm D's. Though t' flights on t' C6 and C5 were safe enough, I would restrict flyin' it on these motors t' calm days. I would nay build this again with t' 18mm mount, matey, so t' parts list included is for use with a 24mm mount. Arrr! Arrr! T' basic construction would remain t' same except for this change. Arrr! Arrr!

{short description of image}

Engine pod construction:

Mark each engine pod tube in 3 places at 120 degrees apart. Arrr! Ya scallywag! One mark will be for alignment o' t' win' joint the other two for t' bass wood strips. Glue t' basswood strips onto t' aft o' t' engine pod tube. Ya scallywag! Mark t' front of the engine pod tube 1/2 inch from t' end. Begad! Arrr!

Trim t' tube coupler into t' 4 1/2" long sections and t' Copper Head tubes into 28, me bucko, 1" long sections. Aye aye! Ahoy! Cluster up t' Copper Head tubes into 7 bundles each and glue into t' 1/2" sections o' tube couplers so 1/2" is exposed. These are t' engine pod nozzles. Well, blow me down! Glue t' "nozzles" into one end o' each engine pod tube so t' coupler tube is flush with t' end o' t' BT20. Aye aye! Avast!

Glue one wire nut into each CR5-20 so t' base end o' t' wire nut is flush with t' edge o' t' centerin' ring. I used CA for this. Glue these "intakes" into t' other end o' t' engine pod tubes so t' front edge o' the centerin' rin' is 1/4" into t' tube. Aye aye! Blimey!

{short description of image}

Main fuselage construction:

Mark t' body tube for t' main wings; launch lugs and t' fairings usin' t' markin' guide. Glue up t' wing parts. Well, blow me down! I didn't streamline t' win' edges; I just rounded them off a bit after they were all glued up. Well, blow me down! Blimey! Be sure t' keep the root end and t' engine pod root ends parallel. Begad! Glue t' root fairings on each root end and round off t' front edges. I glued t' engine pods t' t' wings before I glued t' wings t' t' body tube. Blimey! T' pod root o' t' win' is set at t' mark made 1/2 inch from t' forward end o' t' pod tube. Avast! T' aft edge o' t' win' is flush with t' aft o' the body tube. Blimey! Begad!

T' 3-inch launch lug is glued t' t' 3 inch x 1/8-inch square strip and glued t' t' aft end o' t' body tube. T' 1-inch lug with t' 1-inch 1/8-inch strip is glued 12 inch from t' rear, arrr, matey, matey, measured t' t' front end o' t' lug. Glue t' 1/8 x 3/8 strips t' each side o' t' lugs after gluin' on t' launch lugs. 

Glue t' 2-inch 3/16 strip with t' angle cut at t' aft o' t' body tube, ya bilge rat, glue in t' razor cover then but the 4-1/4" strip in front o' t' razor cover with t' angle end at t' front.
T' canards are glued t' t' body tube 9 1/4" from t' aft and at 90 degrees t' t' launch lugs. Well, blow me down! Arrr!

To make t' cockpit canopy on t' nose cone I used one o' t' plastic covers from a stick deodorant. I trimmed off t' lip around t' outside and then hand trimmed t' edges with an X-acto knife until I had a nice matched fit. Ya scallywag! Blimey! I glued t' canopy onto t' nose cone with medium CA and filled t' gaps with thick CA, ya bilge rat, then sanded t' joint smooth. I positioned t' aft o' t' canopy 1/4" from t' shoulder o' t' nose cone. 

{short description of image}

Photo-1: On t' left are a "nozzle" assembly with t' Copper Head tubes and an "intake" assembly with a wire nut. Ahoy! Blimey! T' ridges on t' wire nut add a bit o' detail t' t' intakes. On t' right top is an unmodified deodorant cover. Arrr! Blimey! Below it be t' one trimmed and ready t' CA t' t' nose cone. 

{short description of image}

Photo-2: This is a close up o' t' canopy already CA'd onto t' nose cone. Ahoy! Since I don't know t' Estes part number for this particular cone, you should be able t' identify it from this shot. Well, blow me down! Blimey!

{short description of image}

Photo-3: This is an overall view o' t' model, less paint o' course. Blimey!

{short description of image}

Photo-4: A side view o' t' model. It doesn't show up well, me hearties, ya bilge rat, but t' disposable razor cover can be seen between the two dorsal basswood strips. Avast! Blimey! Begad! Blimey! Blimey! Blimey!

{short description of image}

Photo-5: Rear view. T' fuselage strips, shiver me timbers, shiver me timbers, root strips and t' orientation o' t' wings show up well in this view.

Photo-6: On t' pad for maiden flight. Arrr! Unfortunately, I didn't get a usable photo o' it at lift off. Blimey!

 

comment Post a Comment