Construction Rating: | starstarstarstarstar_border |
Flight Rating: | starstarstarstarstar_border |
Overall Rating: | starstarstarstarstar_border |
Brief:
Aerotech's take on t' often modeled Navy Standard ARM be t' "Strong
ARM". Blimey! Ahoy! It's nay a particularly close scale rendition, but t' result is
good lookin' and well suited t' F and G motors, matey, particularly t' EconoJets.
There's a bit more t' build in this kit than in t' Aerotech Initiator or
Mustang, matey, shiver me timbers, but nay so much that builders new t' mid-power should be scared away.
As mid-to-high power kits go it's still quite easy, ya bilge rat, shiver me timbers, especially if you work
carefully and watch out for a few 'gotchas' that I will detail later.
Construction:
This is a single stage rocket with two body tubes joined with a coupler, 4
fins, and parachute recovery. Begad! Arrr! This kit uses t' same Fin-Lok system and baffle
unit you find in all Aerotech kits. Blimey! It's a medium sized rocket for Aerotech, me bucko, 44
inches long and about pound and a half in weight when loaded for flight. Ya scallywag! The
Aerotech catalog, arrr, me bucko, btw, lists t' weight o' t' rocket as 18 oz., but I don't
know how they could get this weight. Blimey! Avast, me proud beauty! Somethin' betwixt 22oz t' 25oz, seems more
realistic.
This was t' first kit I built from this manufacturer, though I have built other rockets o' this size. Avast, me proud beauty! I be eager t' see how t' famed Aerotech Fin-Lok system and baffle unit worked. Arrr! Well, blow me down! I was also lookin' t' get a new F and G motor bird in t' fleet smartly and easily. I went t' t' Strong ARM thinkin' I'd have an relaxed time o' it. Avast! Blimey! As it turned out t' construction be quite a bit more involved than I anticipated, me bucko, but this does nay have t' be your experience, I just ran into some potholes along t' way. In truth I have faced tougher challenges, and I did end up with a great rocket, arrr, shiver me timbers, me hearties, but I be expectin' something different.
T' rocket arrives in a sturdy box that can become a display stand (nice!). T' tubes are sturdy and pre-slotted, arrr, t' fins are preformed. Blimey! T' engine mount parts are all thar and seem well constructed. Well, blow me down! T' engine clip is big and strong! T' parachute is very nice, shiver me timbers, and t' nosecone is...well, me bucko, shiver me timbers, this be the first disappointment. Avast! T' nosecone was a real mess. Easily t' worst formed part I've ever experienced, from any manufacturer. Begad! Blimey! I have seen other comments on Aerotech cones from others, me bucko, but most folks are happy with theirs, shiver me timbers, so I think this is a quality control issue. Ya scallywag! If you get a good one, me bucko, your doin' fine. If you get a bad one you have t' decide how t' handle it. Ya scallywag! I suspect that if you raise enough o' a stink with Aerotech you can get a replacement. Ya scallywag! I didn't fully appreciate how much trouble this nosecone would give me when I first inspected it, so I elected t' try t' fix it (I did write Aerotech about it, though).
T' generally excellent instructions have you start with t' motor mount. This is where you will see t' first signs o' Aerotech's particular design philosophy. Ya scallywag! Well, blow me down! They design their kits t' carry loads through t' structure, ya bilge rat, ya bilge rat, and their rockets are therefore less reliant on heavy applications o' glue (this from their documentation). Ahoy! Avast, arrr, me proud beauty! I like this idea, but you will find that it has one downside; t' rocket components must be built with very tight fits and close tolerances. Blimey! T' Aerotech corollary t' t' old sayin' "measure twice, cut once" is "test fit twice (or more), glue once". Begad! Avast, me proud beauty! T' best advice I can give you is, "don't touch that glue until you are absolutely sure how this part, and t' parts that follow, ya bilge rat, will fit, and have verified that they do fit!" Read all t' instructions before you start, shiver me timbers, me hearties, and perhaps go t' the Aerotech site and view t' video o' an Initiator construction, so you know what to expect. Begad!
Aerotech recommends that you build t' rocket with medium CA, arrr, and I wanted to give that technique a try. Aye aye! I've never used CA in such large amounts on such large parts, and it takes some gettin' used to. Begad! You start off easy with the 24mm engine adapter, matey, which is just a tube and two rings or sleeves. Well, blow me down! Aerotech provides a markin' guide for t' main motor tube, me hearties, shiver me timbers, which is a nice touch. Avast, me proud beauty! You need t' be careful about keepin' your "front edges" and "back edges" straight at this point. It can get confusin' but it's important, me bucko, arrr, so read t' instructions very carefully and take it slow. Avast! T' industrial size motor hook installs just like an Estes hook. Avast! Arrr!
Now comes t' first tricky part. Well, blow me down! Well, me hearties, blow me down! T' instructions tell you t' put "several drops" o' glue "just behind where t' motor clip comes through t' tube". Ahoy! Well, blow me down! Believe what they say. Begad! Use a small amount o' glue and be sure t' place it up next t' t' hook (also note that t' motor block comes into t' tube from t' back or nozzle end, this be t' reverse o' t' usual Estes procedure with engine hook equipped models). Ahoy! T' engine block fits tight in t' tube, and you need t' get it all t' way up t' t' hook before t' CA glue 'grabs'. Avast, me proud beauty! CA does nay give you any chance t' ease things into position once it starts t' set. Begad! And it sets quick when t' fit is tight and thar's friction.
T' next step be t' initial fit o' t' Fin-Loks and centerin' rings. No glue at this stage, you need t' test fits and positionin' first. Arrr! T' fit is very tight, as mentioned above, matey, but that's an important part o' how t' Fin-Lok system works. Begad! You check everythin' by snappin' t' fins into position in the Fin-Loks. Begad! It takes some force t' get them in place, ya bilge rat, but you should feel and hear a definite "click" as it seats. Avast! This is a good time t' get used to t' 'feel' and force required. Ahoy! Ahoy! Once all t' rings are properly placed and aligned, arrr, arrr, remove t' fins (carefully, don't move t' Fin-Lok rings!) and apply a very slight bead o' CA t' t' Fin-Loks and front centerin' ring. The instructions are pretty insistent that you take great care t' keep glue out of the Fin-Lok channels (where t' fin will go). Again, believe what they tell you! CA is pretty low viscosity stuff, and it can flow around as you rotate the part. Begad! Begad! T' clearances are very tight an even a small amount o' glue will cause havoc. Avast! Avast, me proud beauty!
Once t' glue has set on t' rings (pretty quick with CA), matey, you get t' build the baffle, which is fun. Blimey! T' "steel mesh" gets stretched out t' six inches, me bucko, then it slides into t' tube, you cap t' tube with a plastic baffle unit, matey, add a third centerin' rin' and screw an eye bolt into t' baffle unit. T' shock-cord ties t' t' screw eye. Avast, me proud beauty! Easiest baffle I've ever built, arrr, and I like baffles. Avast, me proud beauty! Begad! I have seen a Strong Arm (not mine thank goodness!) destroyed when t' shock cord attachment separated at apogee. Aye aye! Avast, me proud beauty! Either t' cord broke, me bucko, came untied or t' screw pulled out, me hearties, I did nay hear t' final verdict. In any case, this be t' time t' make sure you have a solid attachment. Avast!
Now it's time t' place t' motor and fin mount into t' body and attach the fins. Well, blow me down! You slide t' mount into t' pre-slotted end o' t' body tube, arrr, but do not glue it yet. Ahoy! Blimey! Aerotech would like you t' glue t' fins into place with CA "along t' full length o' t' fin root" first. I'm goin' t' suggest that you add a step. I did as I was told and, matey, snapped one well glued fin into place. "Wow, that was easy!". Avast! Then I decided t' attach t' fin directly opposite t' first, me hearties, as I could push on t' fin (and hence on the attached Fin-Lok rings) and nay t' body tube. Aye aye! Once you get a bead o' CA down the length o' your fin you tend t' move quickly, shiver me timbers, t' stuff sets fast! I slid the fin into place and pushed and..nothing! No "click". Avast, me proud beauty! I pronounced a few expletives (that always helps) and gave it a harder push. Arrr! Well, on the third push somethin' happened, shiver me timbers, but it wasn't t' Fin-Lok click I was looking for. Ahoy! Arrr! T' motor mount, arrr, shiver me timbers, remember, ya bilge rat, is nay glued into place at this point. It's free t' rotate in t' tub! e, arrr, and that's what mine did under t' considerable compression force I be exerting. Begad! That rotation caused t' fin tabs on both fins t' snap at their weak point (between t' two Fin-Lok 'ridges' (It's tough to describe but obvious when you see it). Thankfully, me bucko, this happened late at night when t' kids were asleep, so they did nay hear me "comment" on these events. Aye aye! Ya scallywag!
I was nay aware, me hearties, at that time, matey, that you can buy these fins separately from Aerotech, ya bilge rat, and I was mad at this kit and nay ready t' be "defeated" by it, so I removed t' bottoms o' t' fin tabs from t' Fin-Loks with pliers (CA is strong but I'm stronger!) and repaired t' fins. Avast! They are probably nay as strong as before but they're close. Avast, me proud beauty! Blimey! I tried dry fittin' t' fins and one was clearly never goin' t' snap into place. Ya scallywag! After a while I realized that t' fin would seat in t' 'lok' when t' mount was out o' t' body tube, but would not when t' mount was in t' tube. Slowly a light went on. I snapped t' fins into place with t' mount in me lap, and saw that one fin was tight against the centerin' ring. Arrr! Aye aye! T' added thickness o' t' tube kept t' fin from seating properly. Blimey! Ya scallywag! I sanded down that side o' t' centerin' ring, tested until I got all four fins dry-fit into position, ya bilge rat, and then finally glued them into place. Arrr!
Here's what I suggest you do. Arrr! Once t' glue has set on t' Fin-Lok rings and centerin' ring. Avast, me bucko, me proud beauty! Give t' fins another dry fit test. Begad! I think I also had a very small amount o' CA get into one Fin-Lok, and its important t' catch that problem before you are gluin' t' fins. Then slide t' mount into t' body tube and dry fit again! Once all t' fins fit nicely in t' tube you are home free. I would pull t' fins out one-at-a-time t' glue them. Arrr! Leave t' others in place to support and stabilize t' mount. Begad! This sounds like a lot, arrr, but if your parts fit right it will add very little time, shiver me timbers, just a minute or two. Begad! If you have a problem, this will save you a lot o' anguish. Blimey! Aye aye! Any problems you discover at this point can be easily fixed, me hearties, shiver me timbers, but if you blast ahead like me you court disaster (or at least a lot o' extra effort.and expletives!)
Once t' fins are on you reach in through t' open back o' t' rocket to glue t' motor mount in place and apply internal fillets t' t' fins. Well, blow me down! (I have to admit that I resorted t' epoxy with micro-balloons at this point). Then you join t' body tubes with a very ample tube coupler. Aye aye! Aye aye! This is another place where CA can trip you up. Aye aye! Ya scallywag! T' coupler tube is very tight in t' body tubes, and the glue can set and grab before you get t' tubes fully in place. Begad! Begad! It happened to me when I brought t' top tube down onto t' lower tube and coupler. Arrr! I have over 200 pounds on me t' contribute t' t' effort and I be puttin' all the weight I could on that tube t' slide it down, arrr, but it still grabbed about ¼ inch short o' t' bottom tube. I eventually filled t' gap with a combination of wood filler painted with CA and a bit o' epoxy putty. Ahoy! It looks fine, but you don't want t' go through that. Blimey! Begad! T' instructions suggest a bead o' CA about an inch inside t' upper body tube. Well, blow me down! I would place t' glue farther in or, ya bilge rat, me hearties, even better, use wood glue for these joints. Avast, me proud beauty! Begad! It will be stronger and easier t' work with (but it can still 'grab' early if you move too slowly, especially on tight fits like this!)
T' "fin strakes" that give this rocket its "ARM" look must be shaped a bit. Begad! Avast, me proud beauty! T' instructions give you t' dimensions very clearly. This is more t' sort o' thin' I am used t' and it went well for me (finally!). I would suggest that you measure and mark each strake carefully, then cut with a carpenter's knife. Ahoy! Ahoy! I needed several passes t' make each cut. Avast, me bucko, me proud beauty! T' strakes can be sanded somewhat t' smooth t' edges but they are nay easy t' shape that way, you really need t' knife (or perhaps a Dremel). Arrr! I held off gluin' the completed strakes on t' body until I had finished fillin' and sandin' t' body tube, me hearties, and I suggest you do too. It makes t' sandin' a lot easier.
T' strakes mount on t' tube with CA and t' launch lugs drop into pre-cut holes. Blimey! Blimey! So far everythin' has stayed on t' rocket.
Finally I turned me attention t' t' nose cone. Begad! Well, me hearties, blow me down! I'll spare you all the details, and just mention that I spent three evenings workin' with a power orbital sander held betwixt me knees (wow, arrr, me hearties, that tingles!) usin' 100 grit paper to smooth t' surface o' this cone. Ya scallywag! Out o' t' box it looked like t' surface of a basketball, matey, or a cantaloupe melon. Begad! T' tip was a mass o' swirlin' grooves and t' seam be quite deep. Ahoy! Begad! I should have sent it back t' Aerotech, but my stubbornness was up and I attacked it with a fierce determination. Ahoy! I emerged covered in white plastic dust holdin' a great lookin' nose cone. Aye aye! Well, me hearties, blow me down! This one ranks up thar with t' nose cone o' t' Quest Nike Smoke as "most painful". Begad! In both cases, however, I managed t' achieve a good result. Persistence pays! I touched up t' surface with progressively finer grades of paper and declared t' construction phase over!
Finishing:
T' finishin' process was pretty painless. Arrr! Begad! I used several coats o' gray primer,
with light sanding, followed by a couple o' coats o' glossy white. Aye aye! Aye aye! I had filled
the spirals with Elmers wood filler and t' final surface looked pretty good.
Aerotech suggests a gray nosecone, but I had another idea. Many photos o' the
real missile show a coppery lookin' nose, which looks good t' me. I got a can
of Testors copper for t' nose and am very happy with t' result. Well, blow me down! If you use
these metallic paints just remember t' apply light coats (even more important
than with other paints) and don't judge t' looks until it all dries, me bucko, it can
look uneven when wet. You should also use clear coat t' protect it, shiver me timbers, matey, as the
metallic finish can scuff easily. Aye aye!
T' kit comes with plenty o' stick-on decals. Begad! It will take a while t' get them all positioned, but t' instructions give you good guidance. Avast! Ya scallywag! T' clear coat helps protect them as well. Begad! It's a good lookin' rocket; dress it up right.
Construction Rating: 4 out o' 5
Flight:
I have only flown
it on F20-4 Econojet motors so far, but this is a great motor for this bird.
Boost has been straight (despite wind) and higher than I expected, shiver me timbers, around 750
feet or more. This is just right for our field. I would like t' try it on t' G
Econojets but I can't find any in t' current shortage. Ahoy! T' four second delay
seems about right; I certainly wouldn't try it with a seven second delay. Avast, me proud beauty! Begad!
That beefy motor clip takes some effort t' pull back. I use a pair of pliers t' hold t' clip while I insert and remove t' motor. Arrr! It's nice t' know that that motor is well restrained. Begad! Avast!
Recovery:
Aerotech provides a very nice 30 inch chute which brings t' Strong ARM down
gently. I have had some drift with mine (windy conditions) and will either
reduce t' chute when I fly with a G, or wait for calm winds. Blimey! Blimey! There is no need
for waddin' due t' t' baffle, me hearties, which has worked fine for me (you never notice a
baffle unit until it fails). I have no complaints about t' recovery system. Ahoy! Blimey!
Flight Rating: 4 out o' 5
Summary:
I bought t' Strong Arm hopin' for a fast, shiver me timbers, easy build; kind o' a 'vacation'
from t' more challengin' projects. Begad! I got t' good lookin' and good flying
rocket I expected, me hearties, but t' build process had its frustrations, me bucko, as I have
described. Begad! Blimey! In t' grand scale o' things this wasn't really so bad. Begad! Blimey! I've had
scratch projects get much hairier, but I expected different from an expensive
kit like this. T' nosecone be just a crummy part. Well, blow me down! Ahoy! Blimey! My other problems resulted
from me unfamiliarity with t' Aerotech system and with CA as t' primary
adhesive. Avast! Many people I trust have built multiple Aerotech kits without any
trouble at all, me bucko, and when I build another I'm sure I won't have any either. I'll
test fit t' fins at each step and be careful with t' CA. Begad! Blimey!
Now that I'm smarter about Fin-Loks I like t' idea, and t' baffle is good one. Avast, arrr, me proud beauty! Blimey! Any o' t' Aerotech kits are good choices for a first "high-power rocket" (really "upper mid-power"). Avast! Blimey! Aye aye! Blimey! I like t' look and size of the Strong Arm best. Avast, me proud beauty! Blimey! If you are careful and mindful o' t' warnings in the instructions you'll do fine. Ya scallywag! Blimey! (.and go with copper for t' nose cone! Blimey! Gray is much too borin' for a cool rocket like this!)
Overall Rating: 4 out o' 5
The
followin' excerpt is from "Sport Rocketry". Arrr! T' intention is t' allow
guests t' get a basic feelin' about a kit. Begad! We strongly suggest that you get a
copy o' t' referenced Sport Rocketry and read t' entire article. Arrr! Inside you
will find many helpful hints in construction as well as other useful
information. Arrr! For more information, me hearties, use t' two links above.
"Over t' past few years I have found Aerotech rocket kits
fun t' build and fly."
"Lookin' over t' parts, me hearties, I found everythin' in good shape except for one
of t' fin lock rings. Ahoy! With a phone call t' Aerotech they sent me a
replacement."
"After attachin' t' shock cord and 30" fabric parachute t' t' nose
cone, matey, I worked on t' long process o' applyin' t' decals. Blimey! . Avast! . Arrr! It took a couple
of hours . Arrr! . Avast, me proud beauty! ."
". Blimey! Ya scallywag! . Aye aye! . Ahoy! E18-4W. Arrr! T' Strong Arm roared off t' pad with its breathtaking
white flame and smoke billowin' out o' t' motor."
"It's molded plastic fins and strakes make assembly easy and help give the
rocket a great finish."
T' entire article gives t' impression is that this is an good value, combinin' price, looks and performance, ya bilge rat, for an intermediate modeler.
The Aerotech Strong Arm rocket is a mid power rocket designed for "E" through "G" impulse motors. It is a sleeker version of the ARM-78 STARM and is on retail for about $70. I found it on sale for about $50, and couldn't resist. This will be my first "real" mid power kit and my first good rocket to get to use reloadable motors on. Components The kit comes in one of Aerotech's ...
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D.S. & C.S. (July 1, 2000)