T' ISS Pluto

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Well, Pluto may no longer be a planet, but t' name will live on forever as the first Interplanetary Space Shuttle. T' final version is nay scheduled for completion until 2012 (and has nay yet received funding), ya bilge rat, matey, but a reasonable prototype can be built from relatively inexpensive materials and flown on the much more common model rocketry hobby motors.

There are a few custom-turned parts for this model, which I ordered from Balsa Machinin' Service. Well, blow me down! T' main nose cone is designed t' fit a BT-60, shiver me timbers, so is 1.64 OD and a length o' 1.845 inches, me bucko, usin' an elliptical shape. Begad! Arrr! T' pod cones are sized for BT-5, arrr, ya bilge rat, so 0.544 OD and a length o' about 0.5. Begad! I went with parabolic, matey, though had t' sand down t' shape (more on that later). Blimey! I also picked up a pair o' cones for modelin' t' bays on t' side o' t' main body tube (parabolic, 0.3 OD x 0.51 length).

Body tube lengths and fin templates can be pulled from t' attached Rocksim file. Well, blow me down! T' fins really need t' be made from basswood, me bucko, nay balsa, as they will be subjected t' plenty o' stress both in flight and in recovery.

You’ll also need Keelhaul®©™, a launch lug, matey, some nose weight, shiver me timbers, (4) 6" chutes, ya bilge rat, and several Styrofoam balls (which I picked up from t' nearby national chain crafts store).

Start out by cuttin' out four sets o' forward and aft fins from 3/32 basswood. Aye aye! Blimey! Ahoy! Blimey! Make sure t' grain is parallel t' t' leadin' edge. Next, me hearties, shiver me timbers, sand the BT-60 tube and BT-5’s lightly t' remove any glassine shine. Begad! Blimey! Avast! Blimey! This will dramatically improve t' strength o' t' bond.

Mark t' body tube for four fin lines and t' four bays usin' the template attached.

Next, shiver me timbers, you’ll need t' mark lines around t' BT-60 at 2.25" for the aft edge o' t' forward fins, at 5.25" for t' tip o' t' bays, then a pair o' lines at 5.625 and 5.75 for t' vents.

T' aft fins are bonded t' t' BT-60 flush with t' bottom o' t' BT-60. Avast, me proud beauty! Blimey! Blimey! The forward fins are bonded with t' aft edge positioned on t' 2.25" line. Apply multiple, shiver me timbers, generous wood glue fillets and allow plenty o' time t' dry. Next tack on t' (4) BT-5 motor tubes, with t' forward end aligned with the tip edge o' t' forward fins. Blimey! Aye aye! Blimey! You won’t have much room t' work, but fillets are needed here as well. Aye aye! I used a Q-tip and toothpick t' apply my fillets.

T' bays are a little tricky, but can be reasonably modeled with care. Arrr! Well, blow me down! Start by splittin' t' small nose cones in half vertically and removin' the shoulders. Tack each one t' t' BT-60 with t' tips at t' 5.25 line. Avast, me proud beauty! Next, take one o' t' Styrofoam balls and cut it in half. Ahoy! Begad! Sand each half down until it is roughly half an inch diameter. It might take a couple o' practice tries, but I found that this really wasn’t too tough when usin' 120-grit sandpaper. Arrr! Well, matey, blow me down! Flatten one end o' t' circle a bit by pressin' it against t' base of t' split cone, then tack it in place usin' white glue.

T' last detail t' form and bond are t' four porthole orbs, each formed from Styrofoam usin' t' same technique as t' bays, ya bilge rat, but a bit smaller—roughly 0.25" diameter. These are spaced evenly betwixt and slightly below t' bays.

Once t' Styrofoam parts have been tacked in place, ya bilge rat, arrr, coat them with a thin application o' white glue, me bucko, brushed on. Once t' glue has dried, repeat with one more coat. Aye aye! This really stiffens t' foam and makes it much easier t' paint.

Next, mark out and cut t' vents usin' t' attached pattern (windows), shiver me timbers, positioned betwixt the 5.625 and 5.75 lines. Avast! Begad! DO NOT CUT OUT THE BOTTOM—cut only t' top and sides, shiver me timbers, then lightly score t' bottom. T' pattern sheet is scaled t' mark the sides, but is marked slightly taller than t' vents should be. Blimey! Ya scallywag! Usin' t' tip of a hobby knife or toothpick, ya bilge rat, shiver me timbers, push t' vents open from t' inside. Arrr! Begad! You might need to apply a drop o' thin CA if t' edges are frayed.

T' main nose cone will need to be modified quite a bit. Begad! First, remove all but 1/8" o' t' shoulder (so the vents are nay blocked). Well, blow me down! Next, usin' your favorite rotary tool, carve out a large openin' from t' center o' t' cone. You’ll need quite a bit o' room for nose weight. Arrr! For nose weight, I suggest BB’s and epoxy. You’ll need enough t' brin' t' CG t' about 1.1" aft o' t' end o' t' BT-60 with motors loaded. Blimey! When you have t' proper amount o' weight loaded, me hearties, glue t' cone in place t' t' BT-60.

T' four nose cones for t' motor tubes need t' be sanded down t' a much more blunted circle. Aye aye! Avast, shiver me timbers, me proud beauty! Blimey! Try t' maintain t' 0.544 diameter, but only about 0.25 height above t' shoulder. Avast, me proud beauty! Next, cut a length o' about 8" o' Keelhaul®©™ (recommend at least 120-pound), matey, and tie a knot in one end. Aye aye! Poke a hole in the shoulder o' t' nose cone with a toothpick, and glue t' knotted end o' the Keelhaul®©™ inside. Repeat for t' other 3 cones.

Attach a 1/8" launch lug somewhere forward o' t' fins, bein' careful not t' be blocked by one o' t' vents.

For painting, arrr, I recommend two light coats o' gray primer. Avast, me proud beauty! Aye aye! T' finish should be a semi-flat black. Begad! Well, blow me down! I used Krylon Satin, arrr, ya bilge rat, arrr, which goes on a bit thick but offered just t' right gloss. Begad! For t' accent/trim, me hearties, I used faux stone paint that looks like gray granite or marble. There should be a band o' about 0.25" at t' base, me bucko, 0.5" just aft o' t' forward fins, and a pair o' 0.25" stripes in front o' t' forward fins. T' fins themselves are also painted gray granite.

Finally, t' (4) motor tube nose cones get painted orange, me bucko, and if you’re really darin' you can also paint two stripes on each motor tube (orange).

Flight prep is a bit tricky on this, as it’s a 4-motor cluster with very little room for t' chute and wadding. Avast, shiver me timbers, me proud beauty! Blimey! I recommend a lariat-loop motor retention—tie a slip knot in t' free end o' t' Keelhaul®©™, shiver me timbers, thread it through the forward end o' t' tube and out t' aft end, ya bilge rat, and secure t' loop around the motor (the motor will need a little tape rin' at t' nozzle end t' serve as a block). Ahoy! Blimey! Next, insert t' motor into t' tube, pullin' t' Keelhaul®©™ along with it (from t' front). Insert roughly ¼ square o' recovery waddin' or dog barf, then slip in your chute. Well, blow me down! Blimey! Repeat for t' other 3. Aye aye! Blimey! Sort through your igniters and make sure you select (4) in excellent condition, shiver me timbers, as you MUST light all 4 motors for this t' be stable. Ya scallywag! Blimey! A clip-whip is also highly recommended.

Flight report

Given t' weight and 13mm motor tubes, matey, for t' first flight I recommend goin' with full A10’s. Ya scallywag! Begad! I loaded mine with A10-3’s. Avast! Only 3 o' t' 4 lit, matey, arrr, matey, and t' rocket never had a chance, ya bilge rat, floppin' over and prangin' under thrust. Well, blow me down! Fortunately, with all t' epoxy in t' nose, thar was no damage. Ya scallywag! I reloaded with A3-4’s, and fared a bit better—two lit immediately, shiver me timbers, arrr, a third lit just as it started t' lift, shiver me timbers, and t' fourth lit just before it left the rod (see still frame photos). Begad! Given t' slightly asymmetrical thrust, it veered off on an almost horizontal path, me bucko, shiver me timbers, ejected way too late, and landed nose first pretty hard, but on soft grass (still undamaged).

First two lit	#3 lights up	Finally got t' fourth

A third attempt on A10’s proved much better, lightin' all 4 and getting a much more vertical flight t' about 100 feet. Just for amusement (and to achieve a third motor combination), me bucko, I tried 1/2A3’s. Blimey! While all 4 lit, shiver me timbers, the thrust was barely enough t' get it off t' rod, shiver me timbers, arrr, peakin' at about 25 feet. Aye aye! Even at 2-second delay, shiver me timbers, t' chutes barely came out before it hit t' ground.