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. Aye aye! Ya scallywag! It is a sleeker version o' t' ARM-78 STARM and is on retail for about $70. I found it on sale for about $50, shiver me timbers, and couldn't resist. Blimey! Begad! 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. Ahoy! It looks a little small for a rocket o' this size, shiver me timbers, but everythin' fit in just fine. 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 be lay t' components flat on a table. Aye aye! T' instructions were rolled up in one o' t' body tubes, and so were t' decals, arrr, and I recommend takin' those out too. Ahoy! 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. Begad! T' only problem was a slight warp in t' nose cone.

Construction

Buildin' started with a roll call. Begad! I wanted t' make sure that everythin' was accounted for and that nothin' was bent, shiver me timbers, crumpled, arrr, ya bilge rat, or damaged. Well, blow me down! Arrr! I highly recommend doin' this with EVERY rocket you build. You should always check t' quality o' t' components before buildin' so that it can be replaced or fixed. If thar be a weak link in t' structure, bad things can happen. 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. Begad! Blimey! 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). Aye aye! Ahoy! Afterwards, arrr, ya bilge rat, measurements are taken on t' motor mount and t' motor hook is inserted through a 1/4" slot that you cut. T' thrust rin' and flange are now glued together and pushed up until it butts up against t' back o' t' motor hook. Avast, me proud beauty! Aerotech says t' cement them in place, shiver me timbers, 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. Begad! They are so tight that t' front 1/8" o' me motor tube us torn and t' layers o' paper are separated. Ahoy! Avast! T' get them into place, me bucko, I suggest gently tappin' them into place with a rubber mallet or small hammer.

What comes next is super important. Arrr! Begad! DO NOT glue t' FIN-LOC rings in place until you have test fitted t' fins and they fit properly. 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. Begad! 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 be t' epoxy takin' half an hour t' set. It runs like syrup. Avast! I simply kept rotatin' t' assembly and everythin' worked fine. Aye aye! In t' future, I will use 5-minute epoxy.

Now you make four 1/4" slits at t' top o' t' assembly that are 90 degrees apart, arrr, stretch out t' coolin' mesh, and cement t' baffle in place. Arrr! Unfortunately, I made a stupid mistake and glued in t' baffle before I inserted t' mesh. Well, blow me down! Begad! After about 5 minutes o' wonderin' what t' do, shiver me timbers, matey, I ended up cuttin' away t' first 1" o' t' tube, peelin' t' paper away from t' baffle, insertin' t' mesh, arrr, replacin' t' baffle, 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. Avast! 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. Arrr! Well, blow me down! Now t' whole thin' is glued into place, me bucko, and t' fins are removed and tacked down, me hearties, shiver me timbers, 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, arrr, and t' bottom half is finished!

Now comes t' coupler. Arrr! Blimey! I highly suggest test fittin' t' coupler, ya bilge rat, matey, sanding, 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. Arrr! Blimey! Aye aye! Blimey! When all was said and done, shiver me timbers, thar was still a 3/32 gap betwixt t' two tubes, shiver me timbers, so i filled and sanded it down with two-part epoxy clay from Apogee. Well, blow me down! Avast, 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, matey, ya bilge rat, and that can be a bit o' a challenge. Avast! Make several shallow passes with a new razor knife close t' t' lines that you draw onto t' plastic. Ya scallywag! Aye aye! Then sand down t' last little bit and wipe away t' dust and any remainin' flash. Aye aye! 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. T' problem is that t' launch lugs are already glued on. Ahoy! Ya scallywag! T' avoid this, arrr, either use a straight edge, me bucko, or wait t' put on t' lugs.

Draw t' lines at least 6" past t' lower body tube. Blimey! Now glue on t' strakes.

Next tie t' parachute t' t' shock cord and tie t' shock cord t' t' nose cone. Avast! Ahoy! 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. Blimey! Avast! It didn't come out perfect, matey, ya bilge rat, but it could be a lot worse. Aye aye! T' first thin' I did was wash it (you can use a clean rag) and lightly sand around t' seams with 220 grit sandpaper. Avast, me proud beauty! I filled in t' seams with CA and sanded it down again. Aye aye! I repeated these steps until t' surface was smooth.

Paintin' be a breeze. I applied several light coats o' primer and sanded with 220 grit. Blimey! This posed a problem, however. Begad! I wasn't usin' 320 grit sandpaper and t' paint on t' nose chipped off in several long streaks. Arrr! I decided t' go with it and used 150 grit t' get all o' t' paint off o' t' nose cone. Well, me hearties, blow me down! I repainted it and, shiver me timbers, shiver me timbers, from that point on, matey, used only 320 grit sandpaper. Ya scallywag! 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, shiver me timbers, I masked off t' body tubes and painted t' nose cone silver. Avast, me proud beauty! Blimey! 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. Avast! 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, me hearties, but it be worth it.

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

Or was it...

I was less than satisfied with some o' t' decals because they weren't stayin' down. Begad! I took t' flat end o' me razor knife and pressed them down and smartly applied some clear nail polish. It works just like a clear coat, me bucko, shiver me timbers, 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. Blimey! One o' t' great things about Aerotech kits is that no waddin' is required. Ahoy! All that you have t' do do is t' pack in t' shock cord and parachute. Avast, me proud beauty! T' motor lit on t' first try, and boost was faster than I thought it would be. Avast! It probably got t' about 550'. T' four-second delay is perfect for this rocket, matey, and deployment was at apogee. Avast! T' parachute opened within t' first half o' a second after t' ejection charge went off.

Recovery

T' rocket be was t' spot due t' t' bright yellow 30" nylon parachute. Aye aye! Avast, ya bilge rat, 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, me bucko, me bucko, but perhaps a little on t' fast side. Ya scallywag! Since thar was a light breeze on t' ground and no thermals, shiver me timbers, me hearties, t' rocket landed about 50 yards from t' pad, and nothin' was broken. Begad! T' rocket was in perfect condition and flyable as was.

Flight Rating: 5

Summary

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

Overall Rating: 5
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