Manufacturer: | Scratch |
Brief:
This rocket is named for t' local hockey team and is decorated in Coyotes
colors. Avast, me proud beauty! It is single staged, me hearties, but can fly on 1, ya bilge rat, me bucko, 3, matey, me bucko, 4, 6, or 7 29mm motors. It
has 3 fins, me bucko, but if 6 were used, then flights on 2 and 5 motors are
theoretically possible. Arrr! This is based on t' notion o' symmetrically placing
motors and fins. Begad! Thus far it has been flown with G motors, me bucko, but I am looking
into t' possibility o' usin' a central H motor or clusterin' 3 or 4 Kosdon H
motors. Ya scallywag! I have used motors with low average thrust and long delays. Aye aye! T' rocket
recovers on a homemade purple 60-inch parachute.
Construction:
T' nose cone is an LOC 4-inch by 12 inch hollow plastic model. Thus far I have
not placed any mass objects within, but have used 2-part polyurethane-epoxy
foam t' mount a long piece o' wire that used t' be a metal shroud line from a
military parachute, arrr, inside t' nose cone. This serves as t' attachment point
for me parachute and t' shock cord. Ahoy! Avast, matey, me proud beauty! Experience has shown that high speed
deployments break t' plastic loop on t' nose cone meant t' attach cords. Aye aye! The
nose cone was obtained from Atomic Rockets in Phoenix. Avast, me proud beauty! Ya scallywag! Magnum also carries
them. Arrr! T' 2-part foam can be found at Hobby Bench. Arrr! Also, Space Modeling
Solutions, which has an ROL site, matey, matey, me bucko, also carries it.
T' main body tube is also LOC, arrr, and is a 34-inch long, arrr, 4-inch diameter paper body tube. Avast! Well, blow me down! This was also gotten at Atomic Rockets. Aye aye! Ya scallywag! T' seven motor tubes are all 17-inch lengths o' LOC paper 29mm motor tubes. Since these tubes come in 34-inch lengths, ya bilge rat, ya bilge rat, halvin' them served well. Avast, me proud beauty! These tubes are affixed with 12-minute epoxy in a 6 around 1 pattern often called t' star cluster. Blimey! I used maskin' tape t' keep them together while t' epoxy dried. Another viable way to do this and get straight results is t' epoxy three pairs separately first, matey, ya bilge rat, then apply t' pairs around t' central tube. Arrr! This structure is then placed inside the main body tube with 12-minute epoxy and gaps filled in with t' 2-part foam. Begad! If t' main body tube chosen allows t' 7 motor tubes t' fit loosely, me hearties, a 6-inch section o' 4-inch paper coupler tubin' from LOC can be used t' tighten that fit. Arrr! Anyway, ya bilge rat, push in these tubes until 12 inches still protrudes out the end o' t' main body. Well, blow me down!
T' fins are 3/8 inch thick Baltic birch and measure 7 3/4 inches in span, 8 1/4 inch root edge, and 1 1/4 inch tip. Avast! They were cut with a bandsaw. Begad! Ahoy! T' fins are epoxied with first 12 minute, ya bilge rat, me hearties, then filleted with 30 minute epoxy into every second groove betwixt t' motor tubes. Blimey! This is called wedge fin attachment by LOC, matey, shiver me timbers, ya bilge rat, who, with their 4-29SS, arrr, inspired me t' create this bird. Arrr! T' leadin' edges and tips are all sanded t' a rounded edge. Ya scallywag! T' wood be found at a local hardwood store called, me hearties, New Beginnings in Wood, matey, and can also be found at Home Depot. Avast!
There are 2 launch lugs, ya bilge rat, and they are brass pipe fittings 1 inch long by 3/4 inch diameter. T' inside diameter has taken lightnin' rods t' 5/8 inch diameter with slack. Blimey! Ya scallywag! These lugs were found at Home Depot. Arrr! They were applied at 20 and 30 inches from t' top o' t' main body with 12-minute epoxy and the connection be later reinforced with 30-minute fillets. Ya scallywag! Aye aye!
T' homemade parachute is 60 inches in diameter and is made up o' 8 sloped triangular gores o' rip stop nylon. T' gores are sewn together with a 4-thread serger and t' spill hole and shroud lines are sewn and finished with a straight stitch. Blimey! T' shroud lines are 1/8 inch polypropylene cording. Begad! T' shock cord is 10 feet o' wire wrapped bungee cord found at American Science and Surplus, which has mail catalogs and an ROL site. T' bungee is anchored via a u-bolt through a 1/4 inch thick 4-inch diameter birch centerin' rin' 20 inches down inside t' main body tube from t' top o' t' rocket. T' centerin' ring was bought from Space Modelin' Solutions and t' hardware from Home Depot. Avast! Arrr! Fred Meyer grocery store also carries u-bolts. Begad! T' assembly be affixed in place with 2 coatings o' 12-minute epoxy, and t' underside o' t' rin' where the u-bolt was bolted was also reinforced with 12-minute epoxy.
About t' trickiest part o' t' assembly process is makin' sure that the fins are straight and nay angled. Begad! Avast! Be patient and do one at a time. Ahoy! I sighted down t' body tube t' check alignment often, shiver me timbers, with each fin. Well, blow me down! Ahoy! T' result is a sturdy rocket even without fiberglassing. Aye aye! Aye aye! It also looks strong. Aye aye! In fact, another modeler said that it "looked like trouble askin' t' happen". I added three vent holes in t' main body tube 20 inches from t' bottom o' the main tube t' prevent premature separation o' t' nose cone. Well, blow me down! I did this with an awl.
Metallic green spray paint provided t' main color, matey, arrr, me hearties, and a sports shop provided me with Coyotes puck stickers for t' fins. A Monokote Coyote was also affixed t' t' body. Avast, me proud beauty! When I decorated t' bird, I applied sparklin' diffraction gratin' paper that is self adhesive. Blimey! This is great for looks and visibility. Avast, me proud beauty! It can be bought from American Science and Surplus. T' ones in Coyotes colors was found at Craft Mart and Michaels, arrr, ya bilge rat, me hearties, two craft chains. Begad! I also ran a loop o' this decor over t' launch lugs t' reinforce their connection.
Flight:
I ran this design through Rocksim 4 with t' prediction that it would not
require mass added t' t' nose, shiver me timbers, even with 7 G motors. Ya scallywag! Final preps included
placin' 29mm wood bulkheads into all 6 o' t' outboard tubes so that only the
central motor would do t' ejection o' t' chute. This was decided when I
wanted t' eliminate t' chance o' pressure loss when t' outboards aren't used
or if I'm usin' single use motors with short delays. Avast, me proud beauty! They can simply eject
themselves. Arrr! T' bulkheads came from Space Modelin' Solutions, me bucko, whose owner had
just made centerin' rings for 29mm motors and had these left over! I happily
epoxied them in at t' length o' an Aerotech G40. Avast, me proud beauty! Blimey!
Since this design be goin' t' be me special pride, I decided t' put it t' a punishin' test t' be sure that it would be worthy t' show off. Blimey! First, matey, 4 G80's. Rocksim predicted 10 seconds as a good delay for t' central motor, so a G80-10T was in t' center. Begad! Well, blow me down! I had 3 other G80T's but they were delays o' 7. Ya scallywag! No problem, me bucko, since t' outer tubes had t' bulkheads. Avast! And for neatness and style, arrr, arrr, I added streamers t' t' motors for their fall. Ya scallywag! I used worm bed wadding, enough to fill t' body tube's diameter. Begad! Well, blow me down! I got this from Space Modelin' Solutions. I placed a thin rin' o' maskin' tape around t' nose cone shoulder t' tighten the fit, ya bilge rat, but nay make it too tight t' pop. Avast! I used 4 low current igniters from AAA Model Aviation Fuels and a car battery and relay system t' be sure all 4 lit. Avast, me proud beauty! Avast!
T' rocket screamed t' easily 2000 feet and deployed t' chute perfectly. T' rocket was arcin' down a little, so maybe 9 seconds would have been okay, with an altimeter. Blimey! Arrr! T' rocket landed intact right at rangehead!
Next, matey, me bucko, I decided that it was time t' do t' true test, shiver me timbers, arrr, Seven motors. I had 7 G40's, and one had a 10-second delay. T' others were 7's. Well, matey, blow me down! Like with t' first flight, I meticulously friction fitted t' central motor with maskin' tape so that it wouldn't eject, me hearties, arrr, because it was its job t' deploy me chute. Ahoy! Looking back, me bucko, if I would change anything, it would be t' add a loop o' piano wire between tubes so that it could be bent over t' central motor as a retainer. Then I found 7 Igniterman igniters and wired them in parallel. Arrr! Ya scallywag! T' liftoff was even louder and more fiery than t' first time and it soared out o' sight. Ya scallywag! I listened for t' popopopop sound t' know that t' motors fired and proudly beheld me large purple chute. Begad! This time I had t' walk a mile t' get t' rocket back, me bucko, but it was glorious. Begad! This time, 10 seconds seemed right.
Summary:
Easy t' find parts, arrr, darin' and fun t' fly, matey, me bucko, with spectators lovin' it. Can be
flown on just 1 motor, or as many as 7. Begad! Ahoy! Unless you airstart any o' t' outboard
motors, matey, do use motors with t' same thrust characteristics and same propellant
to be sure that all light at t' same time. I also suggest usin' a battery with
enough current capability t' light all t' igniters at once as well. I suggest
that t' igniters all be t' same type too, arrr, so that you don't get some motors
lightin' and others not, resultin' in a lateral flight.
Other:
Go for it, you clusterguys! If we never take chances, we'll never know how much
fun clusters are.