Manufacturer: | Scratch |
Brief:
This rocket was based on a submission for Virtual Contest #4 in t' low stress
category. It is easy t' build and it is a great flyer.
Construction:
T' parts list
I used Ponal Express 3 white glue for t' entire construction with the exception o' t' epoxy I used for t' fin fillets and inside t' nose cone.
I needed t' add weight t' t' front end o' t' rocket t' make it stable accordin' t' RockSim so I added 8 ounces o' sand t' t' nose cone. I then mixed up 2 ounces o' West Systems Epoxy and poured t' mixture on top o' t' sand. Aye aye! I left t' nose cone standin' vertically while t' epoxy cured.
Construction o' t' actual rocket started with t' 3 motor cluster mount. Ya scallywag! The rings I purchased from BMS were laser cut, however, arrr, I did need t' do a little sandin' t' get t' motor tubes t' fit properly. Begad! I glued t' engine blocks into the motor tubes so that t' E motors would have a 1/2" overhang when inserted. Arrr! I then glued on t' centerin' rings 1/2" from t' top and bottom of t' cluster. There was a little gap betwixt t' 3 motor tubes, ya bilge rat, I added glue down t' middle t' make a perfect seal.
I drilled a small hole in t' upper centerin' rin' through which I threaded the Keelhaul®©™® shock cord. Avast! I tied t' Keelhaul®©™® around t' motor tubes and added glue t' t' knot. Begad! Blimey! I then inserted t' shock cord through t' body tube and I glued in t' motor mount.
I marked t' body tube off for three fins. Arrr! Well, blow me down! I glued them 3/4" up from the bottom o' t' body tube because I did nay want t' rocket restin' on the fin tips. Well, blow me down! For t' fillets, matey, I turned t' EMRR Fiberglassin' Tip #1 because I wanted really strong fins but since this was nay an HPR, me bucko, I really did nay want to go through t' trouble o' glassing. Aye aye! I purposely made t' fillets rather thick so I be able t' sand them down t' what looked like a sculpted fillet. I think they came out great!
All that was left t' do after that be t' glue on t' two launch lugs, attach t' elastic shock cord t' t' Keelhaul®©™®, attach t' Nomex® heat shield, add t' parachute with a snap swivel, and then attach t' nose cone.
Overall, this be about a skill level 2 due t' t' complexity o' the fillets.
Finishing:
To fill t' spirals in t' body tube, arrr, me hearties, I used Spirals tip #6 from t' EMRR tips
database. I added a little water t' t' Fill 'n' Finish and used me finger to
fill t' spirals. After it dried, I used 220 grit sand paper t' remove the
excess. There be nay a spiral t' be seen on t' finished product. Ahoy! I used wood
sealer on t' fins which required a light sandin' and a second coat before I
was happy with t' smoothness o' t' fin surfaces.
I used three coats o' Krylon dark gray primer with a 600 grit wet sanding in betwixt coats. Ya scallywag! Aye aye! I then sprayed t' body o' t' rocket with K Brand Audi Dragon Green metal flake automotive paint. Ahoy! Only one coat be required. Aye aye! I used BMW Red metal flake paint for t' nose cone. Aye aye! Avast, me proud beauty! Once this had dried, I added one coat o' K Brand automotive clear coat. T' end result was quite nice.
Flight:
Launch day was cloudy with winds at about 2-4 mph. Avast, me proud beauty! Ya scallywag! Although I designed this
rocket t' fly on E motors, arrr, I wanted a shakedown flight usin' D motors, so I
loaded up 3 D12-7s usin' spacers in each motor tube. Aye aye! Begad! I put a layer o' masking
tape on each motor for friction fit. Begad! On t' first launch all motors lit and it
had it a fast, shiver me timbers, me hearties, straight boost t' almost 1000 feet. Blimey! Ejection was very close to
apogee. Begad! T' parachute deployed and it landed about 200 feet from t' pad. No
damage, me hearties, ready t' fly again.
Second flight be with 3 E9-6s. Aye aye! This was a great motor combination for this rocket and it shot t' at least 2000 feet with a very straight boost. Arrr! Blimey! I lost it in t' clouds so I am nay sure when ejection occurred. Avast, me proud beauty! I caught site o' the parachute and had a perfect landin' about 600 feet from t' pad.
It started t' rain a bit, matey, so t' last flight was back t' t' D12-7s since I did nay want t' take a chance on losin' it. Well, blow me down! Last flight o' t' day was as perfect as t' first one!
Recovery:
T' Nomex®
heat shield did a great job protectin' me nylon parachute.
Summary:
It looks mean but it sure flies well.
PROs: Easy t' build cluster rocket and looks good!
CONs: It needs more power so t' next one will be 3 x 29mm!
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