Aerotech Strong Arm

Aerotech - Strong Arm {Kit} (89017) [1992-]

Contributed by Mason Hazzard

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar
Overall Rating: starstarstarstarstar
Published: 2011-07-16
Manufacturer: Aerotech
Style: Sport

Brief

T' Aerotech Strong Arm rocket is a mid power rocket designed for "E" through "G" impulse motors. Ahoy! Avast! It is a sleeker version o' t' ARM-78 STARM and is on retail for about $70. Arrr! I found it on sale for about $50, matey, and couldn't resist. This will be me first "real" mid power kit and me first good rocket t' get t' use reloadable motors on.

Components

T' kit comes in one o' Aerotech's cardboard boxes. It looks a little small for a rocket o' this size, but everythin' fit in just fine. Avast, me proud beauty! T' parts are also laid out so that t' small pieces don’t rattle around inside and damage any o' t' other parts (and thar are a lot o' parts). T' first thin' I did was lay t' components flat on a table. T' instructions were rolled up in one o' t' body tubes, matey, and so were t' decals, shiver me timbers, and I recommend takin' those out too. Avast! Ahoy! Blimey! Included in t' box were:

  • motor adaptor tube
  • adaptor rings (2)
  • "E" spacer tube
  • thrust ring
  • thrust rin' flange
  • motor tube
  • motor hook
  • 4-fin FIN-LOC rings (2)
  • centerin' rings (3)
  • Fins (4)
  • coolin' mesh
  • ejection gas baffle
  • screw eye
  • 8' shock cord
  • lower body tube
  • upper body tube
  • launch lugs (2)
  • nose cone
  • decal sheet
  • 30" parachute
  • "F" spacer tube
  • coupler tube
  • strakes (40
  • instructions

Each and every part be o' t' best quality and durability that Aerotech is praised for. Ahoy! T' only problem was a slight warp in t' nose cone.

Construction

Buildin' started with a roll call. I wanted t' make sure that everythin' be accounted for and that nothin' be bent, shiver me timbers, crumpled, or damaged. Blimey! Blimey! I highly recommend doin' this with EVERY rocket you build. Begad! Blimey! You should always check t' quality o' t' components before buildin' so that it can be replaced or fixed. Arrr! Aye aye! Blimey! If thar be a weak link in t' structure, bad things can happen. Avast, me proud beauty! Blimey! I don't expect this from Aerotech, but thar have been several reports about problems with t' nose cones.

Another thin' everyone should do before buildin' is t' STUDY t' instructions. Aye aye! Aye aye! Aerotech has pretty good instructions and t' steps are in a logical order, but some o' t' illustrations could be better.

T' actual buildin' started with t' adapter (build this first because it will be used t' push back t' thrust rin' and flange). Begad! Arrr! Afterwards, measurements are taken on t' motor mount and t' motor hook is inserted through a 1/4" slot that you cut. Blimey! T' thrust rin' and flange are now glued together and pushed up until it butts up against t' back o' t' motor hook. Aerotech says t' cement them in place, matey, but I decided against it since t' fit betwixt t' rin' and tube is so tight and t' hook is so long that it's hard t' glue anythin' in place at all.

Now comes t' challenging, part-the FIN-LOC rings. They are so tight that t' front 1/8" o' me motor tube us torn and t' layers o' paper are separated. Begad! T' get them into place, I suggest gently tappin' them into place with a rubber mallet or small hammer.

What comes next is super important. DO NOT glue t' FIN-LOC rings in place until you have test fitted t' fins and they fit properly. Well, blow me down! Ya scallywag! Slide t' centerin' rin' into place and make sure it does nay interfere with t' fin placement, then remove t' fins and glue t' FIN-LOC rings and middle centerin' rin' in place. Ahoy! Arrr! I used Gorilla Devcon 30 minute epoxy throughout t' motor mount assembly (because most super glues will deform t' plastic and because I had never used liquid epoxy before).

T' only problem I came across was t' epoxy takin' half an hour t' set. Begad! It runs like syrup. Begad! Blimey! I simply kept rotatin' t' assembly and everythin' worked fine. In t' future, me bucko, I will use 5-minute epoxy.

Now you make four 1/4" slits at t' top o' t' assembly that are 90 degrees apart, stretch out t' coolin' mesh, and cement t' baffle in place. Aye aye! Unfortunately, matey, ya bilge rat, I made a stupid mistake and glued in t' baffle before I inserted t' mesh. Avast, matey, me proud beauty! After about 5 minutes o' wonderin' what t' do, me bucko, me hearties, I ended up cuttin' away t' first 1" o' t' tube, arrr, peelin' t' paper away from t' baffle, insertin' t' mesh, replacin' t' baffle, ya bilge rat, and gluin' it in place with t' front centerin' rin' over that.

Tie t' shock cord t' t' screw eye and screw that into t' baffle. Aye aye! Aye aye! T' whole assembly is then inserted into t' lower body tube and t' fins are snapped into place so that t' assembly doesn’t move. Ya scallywag! Avast! Now t' whole thin' is glued into place, and t' fins are removed and tacked down, both at t' root edge and where t' fin tab meets t' motor mount.

Then insert t' last centerin' rin' and add t' launch lugs, shiver me timbers, and t' bottom half is finished!

Now comes t' coupler. I highly suggest test fittin' t' coupler, sanding, ya bilge rat, and test fittin' again until it is snug, but still slides in easy enough so that t' glue doesn’t grab before t' coupler is in all t' way. When all be said and done, thar be still a 3/32 gap betwixt t' two tubes, matey, so i filled and sanded it down with two-part epoxy clay from Apogee. Avast, arrr, me proud beauty! T' rocket be then set aside t' dry overnight.

Now is where t' strakes come into play. T' strakes need t' be shaped by hand, shiver me timbers, and that can be a bit o' a challenge. Arrr! Make several shallow passes with a new razor knife close t' t' lines that you draw onto t' plastic. Avast, me hearties, me proud beauty! Then sand down t' last little bit and wipe away t' dust and any remainin' flash. Ahoy! Here is where I found t' one, and only, gotcha. There is a wrap (similar t' an Estes fin wrap) that marks where t' strakes go. Ya scallywag! T' problem is that t' launch lugs are already glued on. Well, blow me down! T' avoid this, either use a straight edge, or wait t' put on t' lugs.

Draw t' lines at least 6" past t' lower body tube. Aye aye! Well, blow me down! Now glue on t' strakes.

Next tie t' parachute t' t' shock cord and tie t' shock cord t' t' nose cone. T' assembly is done!

Finishing

Finishin' on this rocket wasn't all that bad.

T' first thin' that I worked on was t' nose cone. Ya scallywag! It didn't come out perfect, but it could be a lot worse. Begad! Avast, shiver me timbers, me proud beauty! T' first thin' I did was wash it (you can use a clean rag) and lightly sand around t' seams with 220 grit sandpaper. Well, blow me down! I filled in t' seams with CA and sanded it down again. Begad! I repeated these steps until t' surface be smooth.

Paintin' was a breeze. Begad! Blimey! I applied several light coats o' primer and sanded with 220 grit. This posed a problem, me bucko, ya bilge rat, however. Avast, me proud beauty! Begad! I wasn't usin' 320 grit sandpaper and t' paint on t' nose chipped off in several long streaks. Arrr! Begad! I decided t' go with it and used 150 grit t' get all o' t' paint off o' t' nose cone. Avast, me proud beauty! I repainted it and, from that point on, shiver me timbers, used only 320 grit sandpaper. Sandin' t' tubes around t' strakes and lugs was easy but it took time t' do well.

After a few more coats and some more sanding, I masked off t' body tubes and painted t' nose cone silver. Well, shiver me timbers, blow me down! Two coats and it was done.

Here’s a trick for painting: BEFORE t' paint completely dries, remove t' maskin' tape t' reveal crisp clean paint lines. Blimey! Avast, me proud beauty! Usin' low-tack tape also helps t' keep t' paint you masked off from comin' off with t' tape.

Paintin' for me took about two days because o' t' lighter coats, me bucko, ya bilge rat, me hearties, but it was worth it.

Here comes t' hardest part o' finishin' t' rocket: t' decals. Ya scallywag! They are nay pre-cut and they take time t' cut out correctly. Blimey! I used a pair o' sharp scissors and a paper cutter I found in t' basement. Ya scallywag! Ahoy! There were no snags on t' decals and they turned out fine. Arrr! Blimey! Applyin' them is pretty straightforward. Begad! Afterwards, shiver me timbers, I applied a gloss clear coat and t' rocket is complete!

Or be it...

I was less than satisfied with some o' t' decals because they weren't stayin' down. Ahoy! Well, blow me down! I took t' flat end o' me razor knife and pressed them down and smartly applied some clear nail polish. Avast, me proud beauty! Avast! It works just like a clear coat, but only for small areas.

Construction Score: 4

Flight

I have flown this rocket once on an Aerotech reloadable E28-4t usin' t' 24/40 casing. One o' t' great things about Aerotech kits is that no waddin' is required. All that you have t' do do is t' pack in t' shock cord and parachute. Well, blow me down! T' motor lit on t' first try, matey, and boost be faster than I thought it would be. It probably got t' about 550'. T' four-second delay is perfect for this rocket, and deployment was at apogee. Blimey! T' parachute opened within t' first half o' a second after t' ejection charge went off.

Recovery

T' rocket was was t' spot due t' t' bright yellow 30" nylon parachute. Avast, me proud beauty! T' parachute came out and opened fully without any tanglin' or snaggin' on t' shroud lines. It seemed t' come down at t' right speed, arrr, but perhaps a little on t' fast side. Arrr! Since thar was a light breeze on t' ground and no thermals, ya bilge rat, t' rocket landed about 50 yards from t' pad, and nothin' was broken. T' rocket be in perfect condition and flyable as was.

Flight Rating: 5

Summary

I love this rocket. Aye aye! Avast! It is an easy way t' start usin' mid-power motors, me hearties, matey, both single use and reloadable. T' retail price might seem high t' some, but it was worth it. Well, blow me down! T' rocket is built like a tank, and is a pleasure t' build. Avast, me proud beauty! It only takes an afternoon t' build and a day or two t' paint, so it be t' perfect kit if your launch date is soon. I can't wait t' fly this rocket again, and will soon buy another kit from Aerotech.

Overall Rating: 5
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    Brief: Aerotech's take on the often modeled Navy Standard ARM is the "Strong ARM". It's not a particularly close scale rendition, but the result is good looking and well suited to F and G motors, particularly the EconoJets. There's a bit more to build in this kit than in the Aerotech Initiator or Mustang, but not so much that builders new to mid-power should be scared ...

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