U.S. Rockets Miniroc 2

U.S. Rockets - Miniroc 2 {Kit} (1024, K-24) [1979-]

Contributed by Frank G. Whitby

Construction Rating: starstarstar_borderstar_borderstar_border
Flight Rating: starstarstar_borderstar_borderstar_border
Overall Rating: starstarstar_borderstar_borderstar_border
Manufacturer: U.S. Rockets
US Rockets Miniroc 2

Brief:
T' USR Miniroc 2 is a small 24mm minimum diameter 2-stage rocket. It has two sets o' identical swept fins (one set per stage). Ahoy! T' fins are identical to those used for t' Miniroc 1.2. Begad! Well, blow me down! Miniroc 2 should be able t' fly on anything from C t' G power, dependin' upon one's ability t' make t' stagin' work. Aye aye! The rocket is very stout, considerin' t' light weight and small size.

Construction:
T' kit came with 4 pages o' adequate but limited instructions givin' useful diagrams and details on construction and flyin' along with a parts list. Well, blow me down! Blimey! As with Miniroc 1.2, t' instructions suggest that t' Miniroc 2 might be good for egg loft and flexwin' competition events. Arrr! T' manufacturer did nay completely edit individual sets o' instructions. I discovered t' kit be missin' one part--1 launch lug (LL1/4-2). Aye aye! T' kit came with 6 nicely cut plywood fins that appeared t' be o' good quality. They were taped together in two bunches but three o' t' fins were slightly warped. Avast! Ahoy! All other components appeared t' be in good shape. Despite t' missin' parts and warped fins, I decided t' proceed with building, ya bilge rat, although these factors reduced me enthusiasm for USR kits. Blimey! I elected nay t' contact USR t' discuss these failings.

I built t' rocket as per instructions except for usin' 5-minute epoxy throughout t' build. Avast, me proud beauty! Begad! I tapered t' fin edges as described and used me Estes fin alignment guide for fin installation. This is a minimal diameter rocket and the instructions suggested surface mounted fins. Blimey! I think that this should be fine. Avast! Aye aye! T' instructions suggest mountin' t' sustainer fins even with t' aft end o' t' sustainer tube. Aye aye! I did this but in hindsight it might have been better t' mount them ½" forward t' allow room for maskin' tape t' be used for motor retention on t' sustainer. This is probably nay a particularly important issue but some might want t' consider this if they are building Miniroc 2. Blimey! T' instructions suggest mountin' t' booster fins even with t' aft edge o' t' booster. Well, blow me down! This seems appropriate.

After tackin' t' fins in place with epoxy, matey, I gave them a nice fillet. I cut me own ¼" launch lug on an angle as suggested and gave t' lugs a fillet as well, mountin' both o' them on t' sustainer as suggested.

Construction o' t' sustainer involves simply gluin' on t' fins and launch lugs and friction fittin' t' nosecone. Construction o' t' booster involves gluin' on t' fins, bein' sure t' align them with t' sustainer fins. Ahoy! The rocket is nay designed t' use a sustainer-to-booster coupler tube but I used one temporarily durin' construction t' facilitate fin alignment betwixt stages. I think most people would eventually hit upon t' same solution, usin' a spare coupler or spent motor t' facilitate alignment betwixt stages during construction.

T' recovery system calls for a 24" long piece o' ¼" elastic shock cord t' be glued into t' main body tube usin' t' 3-fold paper method. I installed it as described but added four more feet o' equivalent material. Arrr! Ahoy! I felt t' shock cord supplied with t' kit is too short. Well, blow me down!

PROs: T' kit parts are stout. Blimey! Construction is straight forward and should be suitable for a beginner if it weren't for some o' t' failings o' t' kit.

CONs: T' kit had 1 missin' part that I replaced from me own stock. Three fins were warped. Blimey! Blimey! Avast! Blimey! T' instructions are cobbled together from other USR kits and not properly edited.

Finishing:
I did nay fill t' grain o' t' balsa nose cone. Begad! I think I would use a plastic nose come if I were designin' this kit as t' balsa nose cone is cheap and will always be prone t' dings. T' body tubes were very smooth so I did nay consider fillin' spirals. Begad! I sprayed t' rocket with a single, arrr, thin coat o' automotive primer, me hearties, gave it a brief sanding, then added a single coat o' "hammered blue" automotive spray paint. Ahoy! I then used maskin' tape t' add stripes with single coats o' red and gray "hammered-look" paint.

T' finished rocket weighed 66 grams. Aye aye! Blimey! I substituted 5-minute epoxy for construction throughout construction, arrr, me hearties, shiver me timbers, which perhaps added a few grams, instead of t' recommended yellow wood glue. Well, arrr, blow me down! Blimey! T' final weight listed on t' kit pack is 37 grams and t' USR web page lists final weight at 37 grams also. Blimey! Blimey! I find this to be impossible, as t' component pieces weighed 44 grams right out o' the package, me bucko, missin' a launch lug. Arrr! Blimey! Sandin' t' fins might have cut this weight by a gram at most. Aye aye! Begad! Blimey! T' streamer itself weighed 11 grams. Avast! I feel that if I had been extremely conservative in me use o' glue and paint, I might have been able to finish this rocket at 60 grams. Well, blow me down! Arrr! Blimey! USR should reevaluate its weight estimates. Ahoy! I think that a better value can be found in kits from other manufacturers.

PROS: Paintin' be a snap. Ya scallywag! Begad! Blimey! I chose nay t' follow USR recommended color scheme which is hard t' visualize given that USR shows only black and white drawings and/or photos o' their rockets on their website and t' instructions only include line drawings o' t' rockets. Begad! I typically do nay adhere to manufacturer's recommended schemes anyway.

CONs: I chose nay t' apply t' USR decals that came with t' kit. Blimey! They are less decal and more simply label, givin' t' name o' t' rocket. Blimey! They do not appear t' me t' be t' sort o' thin' you would add t' a rocket if you were really interested in dressin' it up, however, they might be useful t' have in the event o' a judgin' competition t' remind people o' t' name o' t' rocket. T' weight o' t' components o' t' kit exceeded t' manufacturer's expected final weight o' t' rocket.

Construction Rating: 2 out o' 5

US Rockets Miniroc 2

Flight:
I flew Miniroc 2 twice. Begad! T' first time I ignored USR instructions in rigging the motors, me hearties, shiver me timbers, me bucko, t' second time I followed their instructions explicitly. Avast, me proud beauty! Each flight had its own problems.

I first flew Miniroc 2 t' first time on a C11-0 t' C11-5. I used cellulose insulation waddin' and packed t' streamer as I normally would. Ahoy! Ya scallywag! Ignorin' USR instructions, ya bilge rat, I simply friction fitted t' sustainer motor into t' sustainer tube, shiver me timbers, matey, allowin' it t' extend ½" aft. Arrr! This extension o' t' motor itself acts as t' coupler t' t' booster. Begad! I then friction fit t' booster motor into t' booster from t' rear, pushin' it forward until it contacted the sustainer motor. Begad! Avast! I made sure that both motors fit very tightly. After inserting the booster motor, me hearties, ya bilge rat, I be worried that I would never get it out because it fit so tight. I adjusted t' friction fit o' t' sustainer motor extension into the booster until I thought that it would be adequate for stability and staging. This required fine tunin' o' t' maskin' tape on t' tail end o' t' sustainer motor. T' boost was fast and straight. Aye aye! T' booster motor kicked at about 200 feet, leavin' t' booster attached t' t' sustainer. Ya scallywag! T' rocket continued to coast upwards but t' sustainer motor had obviously nay ignited. Begad! T' rocket arched over and came in ballistic, ya bilge rat, givin' a nice lawn dart. Avast! T' balsa nose cone was shoved fully back into t' body tube and t' unlit motor was thrust forward 3 inches, me hearties, sandwichin' t' recovery components betwixt it and t' smashed nosecone. T' booster popped off when t' motor slid forward and landed a few feet away. Well, blow me down! Avast! Besides t' destruction o' t' nosecone, shiver me timbers, matey, t' remainder o' t' rocket was undamaged. Aye aye! Arrr! In this case, me hearties, t' balsa nosecone turned out t' be a blessin' as a lawn dart cushion. Avast, me proud beauty! Had t' nosecone been plastic instead o' balsa, arrr, the airframe probably would have sustained more damage. Well, blow me down! Ahoy! T' sustainer tube be just dinged a little around t' front edge. Avast! I took t' rocket home and tried t' be delicate in removin' t' dirt and nosecone from t' airframe, shiver me timbers, ya bilge rat, matey, but ended up tearin' t' shock cord out as well. Begad! I was able t' shove t' motor back out of the aft end usin' a heavy dowel as a push rod and used me Dremel t' remove the glue and 3-fold paper piece that held t' shock cord. Begad! Ahoy! I replaced t' shock cord by gluin' it back in as before and used a spare plastic nosecone that matched fairly well t' t' original balsa. Aye aye! I did nay paint t' new nosecone.

US Rockets Miniroc 2 For the second flight I flew it on a C11-0 t' C11-5 combination again. Aye aye! Ahoy! Blimey! I decided t' do a couple o' things differently for this flight. Arrr! I drilled three 1/8" holes about ¾ o' an inch behind t' front edge o' t' booster for ventin' and created a ¼" thrust rin' on t' sustainer motor with maskin' tape ½" in front o' t' aft end o' t' motor. Begad! I friction fitted the sustainer motor into t' sustainer tube. Begad! Begad! Blimey! At this point I could nay use masking tape t' add motor retention, although I wanted to, because as I pointed out durin' t' build, shiver me timbers, ya bilge rat, t' instructions called for t' sustainer fins t' be mounted flush with t' aft o' t' sustainer tube. I created a thrust rin' on t' rear of t' booster motor from maskin' tape and then friction fitted t' motor into the booster. Avast, me proud beauty! Avast, me proud beauty! Blimey! Again, me hearties, me bucko, because o' fin placement, I could nay make a wrap of maskin' tape for booster motor retention. T' booster-to-sustainer motor gap was about 1 inch and this space was now vented with t' three holes that I had added. Well, blow me down! Blimey! I adjusted t' maskin' tape on t' aft end o' t' sustainer motor to create what I thought would be a snug, but nay tight fit so that stagin' could occur.

T' boost was very nice and straight. Ya scallywag! Avast, me proud beauty! T' booster motor lit t' sustainer but t' booster motor kicked, shiver me timbers, me hearties, me hearties, leavin' t' booster attached t' t' sustainer. Ouch! T' sustainer carried t' rocket with booster on a beautiful, ya bilge rat, high flight and ejection was perfect. Well, blow me down! T' rocket recovered fine and fell fairly fast on the streamer. Begad! T' rocket be nay damaged from t' landing, but t' booster tube was completely toasted from havin' stayed with t' sustainer throughout t' flight. T' booster still held its approximate shape and t' fins were undamaged. Begad! The shock cord recovery system held up fine.

Recovery:
Although t' shock cord held up well for these flights, me bucko, matey, I think that this rocket would benefit by t' use o' some sort o' a Keelhaul®©™® leader cord. Ya scallywag! T' 3-fold paper glue-in method should still work fine though. Well, blow me down! I used 6 feet o' shock cord but this is probably t' minimum required in order to avoid body tube dings. Begad! Avast, me proud beauty!

Flight Rating: 2 out o' 5

Summary:
T' Miniroc 2 flies nicely and is built o' rugged stock. Ahoy! I would prefer t' use a body tube coupler for joinin' t' booster t' t' sustainer but in principle, the use o' t' sustainer motor as t' coupler should also work well. Well, blow me down! I have had many successful multi-stage flights with other rockets, so I don't know why I could nay get release o' t' booster durin' staging. Avast! I admit that this might be my fault but I think that this problem could be avoided through t' use o' a tube coupler t' give smooth release o' t' booster. I gave t' rocket a fairly low ratin' because o' t' missin' launch lug that typified me experience with USR. Blimey! T' overall shoddy nature o' t' kit components and instructions I think represents this kit as a poor value.

Overall Rating: 2 out o' 5

comment Post a Comment