Public Missiles Matrix

Public Missiles - Matrix

Contributed by Carl Tulanko

Manufacturer: Public Missiles
Rating
(by Carl Tulanko)

Brief:
T' PML Matrix is a sport rocket advertised as a meteor defense weapon with a futuristic look about it. T' kit is a 3” diameter model made for H and I high-power motors and uses a 3 fin configuration, arrr, matey, although thar are twelve fins total for t' model.

Motor MountConstruction:
T' kit came in a bag and included all t' necessary parts; 3” diameter “Quantum” body tube (1/16” thick semi-flexible plastic tube), matey, a 12” long payload tube section, nosecone, shiver me timbers, twelve G-10 fiberglass fins, bulkhead, matey, piston assembly, ply centerin' rings, 38mm motor mount, matey, 36” parachute, ya bilge rat, all t' necessary hardware, matey, matey, a nice set o' decals and detailed assembly instructions. Well, blow me down! Aye aye! T' payload tube be dado-slotted for t' six upper fins (not slotted all t' way through) while t' main body tube was pre slotted for through t' wall main fins and dado-slotted for t' long stabilizer fins. As usual, me bucko, this is a typical high quality PML kit usin' some o' t' best materials available. Well, blow me down! Component Rating: 5 o' 5

I used 15 minute epoxy throughout t' construction, ya bilge rat, which gave me a little extra workin' time with t' materials. Ya scallywag! Tip: Use 80 grit sandpaper for roughing up all surfaces prior t' gluing; it has more bite than t' recommended 120 grit and will create a stronger bond t' t' surfaces.

You begin by buildin' t' Motor Mount assembly. Once you have glued the black shock cord t' t' side o' t' motor mount tube, me hearties, GLAZE t' top o' the strap with epoxy for added strength. Avast, me proud beauty! Ahoy! Be careful nay t' install t' mount with the strap area under a fin slot; position t' shock strap area betwixt two of the fin slots. Ya scallywag! Also, do nay use t' scotch tape method on t' aft motor mount, as it just breaks off. Avast, me proud beauty! Instead, push t' aft centerin' rin' on, arrr, then once the forward centerin' rin' glue joint has set, use a 6” metal ruler through the fin slots t' push t' aft centerin' rin' back out o' t' body tube.

PML uses a piston ejection system which works very well and eliminates the need for wadding. Begad! Arrr! Once t' piston assembly is built, ya bilge rat, me bucko, glaze t' inside and outside wooden surfaces with epoxy. Well, blow me down! Aye aye! This adds strength t' piston and waterproofs t' wood, so you can easily clean t' rocket after t' day’s flight. Arrr! There is one problem t' note; t' PML 3” kits all tend t' come with an oversized piston. Begad! I have nay seen this problem with t' 2” or 4” kits, shiver me timbers, but, matey, right out o' t' bag, shiver me timbers, t' 3” piston fits very tight inside t' Quantum tube and requires a TON o' sandin' t' get it t' move smoothly. Avast! I have seen t' 3” piston completely shred on an ejection with another friends PML kit, me bucko, matey, even though t' correct powder charge was used. Well, blow me down! Well, blow me down! This was probably due t' t' fact that t' walls o' t' piston were so thin from sandin' it t' fit that it couldn't withstand t' ejection. I resolved the problem by purchasin' a 3” PML body coupler tube as a replacement. Aye aye! The Coupler fits better and gave me t' extra material needed t' “Double” the wall thickness o' t' piston. Blimey! I made a new Piston by cuttin' t' coupler to the length o' t' original piston. Begad! Next, ya bilge rat, t' wooden face was glued into t' new piston followin' t' directions from t' instruction manual. Arrr! Finally, I cut another “inside sleeve” from t' remainin' coupler material. Ya scallywag! The inside piston sleeve was then cut lengthwise and sanded at t' cut area until it could be squeezed together and easily fit inside t' original piston. Ahoy! Avast, me proud beauty! This sleeve be glued inside t' piston usin' epoxy and I made sure it was pushed all t' way forward until it made contact with t' inside wooden piston face. T' final product was a very strong, double thick piston that works like a charm. Ahoy! Avast! Just somethin' t' try if you experience t' same problem. Begad!

Next came t' assembly o' t' bulkhead into t' payload tube, however, there were two modifications that were made t' t' payload area. Avast, me proud beauty! I used a 1 ½” U-Bolt instead o' t' eyebolt supplied in t' kit because eyebolts have a tendency t' eventually pull apart. Arrr! Aye aye! See t' picture for me U-Bolt installation. Well, blow me down! T' other modification made was t' installation o' an altimeter bay. Blimey! I already had a CPR 3000 ready rocket with mounts on me altimeter, so I just needed t' duplicate t' altimeter mountin' bay for t' CPR. Avast, matey, me proud beauty! I purchased two 3” x 1.5” centerin' rings, along with a 1.5” motor mount tube (38mm sized). Avast! T' Motor mount tube was cut t' a length o' 6 ½” and a 1/8” wide slot was cut in t' tube t' a length o' 1” so the altimeter could “breathe”. Arrr! T' two centerin' rings were glued t' the motor tube; t' top rin' was mounted flush with t' end o' t' tube and the lower centerin' rin' was mounted 2 ½” from t' other end o' t' tube. This assembly was glued into t' payload section with t' top centerin' ring recessed 4 ½” from t' top o' t' body tube. Avast, me proud beauty! Avast! Three 3/32” holes were drilled through t' payload tube, arrr, which allow t' altimeter t' sense outside pressure. Arrr! Begad! Finally, I inserted a piece o' 1/2" hobby foam on top of the altimeter and used t' nose cone for retention, since it is attached with screws. Avast! Avast, me proud beauty! See t' pictures for t' altimeter mount and installation.

Lower FinsT' lower fins were glued on next; I put a small amount o' epoxy on t' edge o' a fin, shiver me timbers, shiver me timbers, arrr, then inserted it through t' fin slot and used maskin' tape t' hold it down on t' motor tube. Begad! Once t' three main fins were glued, matey, I cut 1 ½” wide strips o' 2oz fiberglass cloth to t' length o' each fin, then glassed t' space from t' motor mount t' the fin t' t' inner body tube. Avast, me proud beauty! I soaked t' cloth in epoxy then folded it around a ½” wide stick, matey, which allowed me t' insert it into t' tube. T' stick was then used t' make sure t' cloth be pressed down on all surfaces. Blimey! This adds strength inside t' body tube area, especially where t' fins are glued to the mount. Aye aye! Blimey! Our club does a lot o' cold weather launches, so I glass all me fins inside and out for added strength. Upper FinsFollow t' directions for mountin' t' long stabilizer fins, which I installed after t' lower fins were set. Ahoy! Blimey! Once t' stab fins are in place, shiver me timbers, glue t' upper fins t' t' payload tube. Install three fins at a time, then turn t' payload tube and re-use t' main fins for alignment o' t' last three payload fins. Avast, me proud beauty! Note: even though this kit has 12 fins total, shiver me timbers, arrr, t' assembly was very easy. Begad! Blimey! You don’t see many o' these kits out there, probably because o' t' amount o' fins on t' model. Avast! Ya scallywag! Don’t be intimidated! It’s very easy t' build and looks great when finished. Arrr! Arrr!

In addition, I fiberglassed t' lower fins usin' 1 ½ oz cloth and 15 minute epoxy, then I applied small fillets t' t' upper and long stabilizer fins and larger fillets t' t' launch lugs and lower fins since they would be absorbin' t' majority o' t' shock from landing. Aye aye! Begad! Finally, three holes were drilled and tapped in t' bottom o' t' model for t' PMR motor retainer, a few drops o' medium CA applied, matey, ya bilge rat, matey, then t' threaded retainer plugs were installed. Construction Rating: 4 o' 5

Finishing:
White Krylon primer was applied prior t' t' first sandin' and I used 100 grit to cut away any excess epoxy resin left from t' fiberglassin' and t' blend in the cloth seams. Blimey! I used an electric sander in t' glassed area, me bucko, me hearties, which helped cut t' work down considerably. Avast, me proud beauty! Avast! A few more coats o' primer were added, then I wet sanded with 220 grit. Avast! Finally, a few more coats o' primer were added and I started with 400 grit and finished it up by wet sandin' with 600 grit. Aye aye! Dark Red Glossy Krylon paint was used on fins, matey, while t' nosecone and body tubes were done in Testors Chrome. Avast! T' colors were picked by me son, Thomas, and I must say it really looks good once painted. Avast, me proud beauty! It was a bit tricky applyin' t' paint the way I wanted though; I knew t' Chrome be very sensitive t' touch, ya bilge rat, so I sprayed it last. Begad! T' tricky part be maskin' all t' fins after they were painted, me hearties, but it turned out well. Avast! Aye aye! I used Testors Clear Glosscoat t' protect the finish, me bucko, since t' chrome paint has a tendency t' mar very easily. Aye aye!

Decals were nay applied until later on and are nay shown in t' launch pics. As a last step, t' shock cord and parachute were attached per the instructions. Ya scallywag! T' 36” parachute deviates from t' yellow/purple PML standard and is red/white in color, shiver me timbers, which I believed attributed t' t' color scheme decision. Avast! I did add a 1” link, which allows me t' attach the parachute, me bucko, matey, then remove it later for cleaning. Blimey! Don’t forget t' tack glue the shock cord knots with a drop o' epoxy as they can work their way loose. Finish: 5 o' 5

Construction Rating: 4 out o' 5

LaunchFlight:
My son and I went t' t' last launch o' t' sprin' season for our Tripoli Mid-Ohio Club. Begad! Everyone out thar helped set up, then it was time t' get some rockets on t' pads. Avast, me proud beauty! It turned out t' be a beautiful day with temperatures in the 70’s with a decent, but manageable breeze. Avast! Our first launch o' the Matrix was on a 38mm H123W with a short delay. T' rocket be carefully prepared and placed on t' pad. Aye aye! Avast, me proud beauty! It was a real thrill seein' t' look on my son’s face when he observed his first HP launch! T' launch was spectacular for such a small load; It traveled a nice straight line leavin' a really cool trail o' white smoke behind.

Recovery:
T' parachute ejected at apogee and t' rocket drifted safely t' t' ground. T' design o' t' long stabilizer fins on this model works well and t' stab fins never touch t' ground durin' landing. Well, blow me down! It be such a good flight that we had t' do it again. We launched twice more, me bucko, once on a I161W-medium and once on another H123W-short. Both flights went as planned, me bucko, shiver me timbers, but t' I161 really gets it off t' pad in a hurry! On t' final flight, matey, one o' t' lower fins stuck in the ground like an axe durin' landin' and was suspendin' t' upper part o' the rocket in t' air. Aye aye! After checkin' t' model for damage and realizin' it was fine, it proved t' me yet again that fiberglassin' fins really pays off! We did get it a bit scratched up in t' field, ya bilge rat, but nothin' that cannot be touched up. That’s just rocketry! Flight/Recovery: 5 o' 5

Flight Rating: 5 out o' 5

Summary:
T' PML Matrix really is an excellent model and, even though it has quite a few fins, it’s a dream t' build and fly. T' small modifications I made were only for me peace o' mind as I want this rocket t' last for a while. Aye aye! Blimey! My only complaint is with t' 3” piston; if they could only ship them a bit smaller in diameter, arrr, it would have been a perfect kit. Begad! Blimey! I had nay doubled up the piston yet, shiver me timbers, even though it be pretty thin. Aye aye! Blimey! I did however buy an extra PML coupler from Ross at Magnum Rockets while we were at t' launch and am in the process o' doublin' up t' piston at t' present time. Well, blow me down! Blimey! That one fault aside, the Matrix otherwise is an excellent kit, good in quality and value, matey, arrr, arrr, with one unique look that really catches your eye! Blimey! Overall Rating: 4.75 o' 5

Overall Rating: 4 ¾ out o' 5

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