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. Avast, me proud beauty! T' kit is a 3” diameter model made for H and I high-power motors and uses a 3 fin configuration, shiver me timbers, 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), me bucko, arrr, a 12” long payload tube section, matey, nosecone, twelve G-10 fiberglass fins, bulkhead, piston assembly, ply centerin' rings, matey, 38mm motor mount, 36” parachute, all t' necessary hardware, a nice set o' decals and detailed assembly instructions. Begad! T' payload tube was 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. Aye aye! Avast! As usual, matey, this is a typical high quality PML kit usin' some o' t' best materials available. Component Rating: 5 o' 5

I used 15 minute epoxy throughout t' construction, which gave me a little extra workin' time with t' materials. Aye aye! 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. Well, blow me down! Blimey! Once you have glued the black shock cord t' t' side o' t' motor mount tube, arrr, GLAZE t' top o' the strap with epoxy for added strength. 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. Avast, me proud beauty! Blimey! Also, do nay use t' scotch tape method on t' aft motor mount, as it just breaks off. Ahoy! Instead, push t' aft centerin' rin' on, then once the forward centerin' rin' glue joint has set, ya bilge rat, use a 6” metal ruler through the fin slots t' push t' aft centerin' rin' back out o' t' body tube. Aye aye!

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

Next came t' assembly o' t' bulkhead into t' payload tube, shiver me timbers, 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. See t' picture for me U-Bolt installation. T' other modification made was t' installation o' an altimeter bay. I already had a CPR 3000 ready rocket with mounts on me altimeter, arrr, ya bilge rat, so I just needed t' duplicate t' altimeter mountin' bay for t' CPR. Aye aye! Begad! I purchased two 3” x 1.5” centerin' rings, shiver me timbers, along with a 1.5” motor mount tube (38mm sized). Begad! Arrr! 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”. Avast, matey, me proud beauty! 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 be glued into t' payload section with t' top centerin' ring recessed 4 ½” from t' top o' t' body tube. Ya scallywag! Three 3/32” holes were drilled through t' payload tube, which allow t' altimeter t' sense outside pressure. Arrr! Aye aye! 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. Begad! Begad! 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, me bucko, then inserted it through t' fin slot and used maskin' tape t' hold it down on t' motor tube. Once t' three main fins were glued, me bucko, I cut 1 ½” wide strips o' 2oz fiberglass cloth to t' length o' each fin, arrr, then glassed t' space from t' motor mount t' the fin t' t' inner body tube. Ahoy! I soaked t' cloth in epoxy then folded it around a ½” wide stick, me bucko, which allowed me t' insert it into t' tube. Begad! Begad! T' stick was then used t' make sure t' cloth be pressed down on all surfaces. Ahoy! Ya scallywag! This adds strength inside t' body tube area, especially where t' fins are glued to the mount. Our club does a lot o' cold weather launches, shiver me timbers, 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. Blimey! Well, blow me down! Once t' stab fins are in place, glue t' upper fins t' t' payload tube. Install three fins at a time, matey, then turn t' payload tube and re-use t' main fins for alignment o' t' last three payload fins. Aye aye! Note: even though this kit has 12 fins total, t' assembly was very easy. Ahoy! Ahoy! You don’t see many o' these kits out there, me hearties, probably because o' t' amount o' fins on t' model. Blimey! Blimey! Don’t be intimidated! It’s very easy t' build and looks great when finished. Blimey! Ahoy!

In addition, ya bilge rat, me bucko, I fiberglassed t' lower fins usin' 1 ½ oz cloth and 15 minute epoxy, me hearties, me hearties, 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! Ahoy! Finally, three holes were drilled and tapped in t' bottom o' t' model for t' PMR motor retainer, matey, a few drops o' medium CA applied, me bucko, 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. I used an electric sander in t' glassed area, which helped cut t' work down considerably. Well, blow me down! A few more coats o' primer were added, ya bilge rat, then I wet sanded with 220 grit. Begad! Finally, matey, shiver me timbers, ya bilge rat, a few more coats o' primer were added and I started with 400 grit and finished it up by wet sandin' with 600 grit. Ahoy! Dark Red Glossy Krylon paint was used on fins, me hearties, while t' nosecone and body tubes were done in Testors Chrome. Avast! Arrr! T' colors were picked by me son, Thomas, and I must say it really looks good once painted. Arrr! 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, so I sprayed it last. Blimey! T' tricky part was maskin' all t' fins after they were painted, me hearties, ya bilge rat, but it turned out well. I used Testors Clear Glosscoat t' protect the finish, shiver me timbers, matey, matey, since t' chrome paint has a tendency t' mar very easily. Aye aye! Begad!

Decals were nay applied until later on and are nay shown in t' launch pics. As a last step, me bucko, t' shock cord and parachute were attached per the instructions. T' 36” parachute deviates from t' yellow/purple PML standard and is red/white in color, matey, which I believed attributed t' t' color scheme decision. Avast! I did add a 1” link, ya bilge rat, which allows me t' attach the parachute, shiver me timbers, then remove it later for cleaning. Avast, me proud beauty! 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. Ahoy! Begad! Everyone out thar helped set up, arrr, then it be time t' get some rockets on t' pads. 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 be on a 38mm H123W with a short delay. Ya scallywag! T' rocket was carefully prepared and placed on t' pad. 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. Ahoy!

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. It be such a good flight that we had t' do it again. We launched twice more, shiver me timbers, once on a I161W-medium and once on another H123W-short. Avast! Both flights went as planned, arrr, but t' I161 really gets it off t' pad in a hurry! On t' final flight, 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. Arrr! 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, shiver me timbers, 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, me hearties, shiver me timbers, shiver me timbers, it’s a dream t' build and fly. Avast! T' small modifications I made were only for me peace o' mind as I want this rocket t' last for a while. Avast, ya bilge rat, me proud beauty! My only complaint is with t' 3” piston; if they could only ship them a bit smaller in diameter, me hearties, it would have been a perfect kit. Ya scallywag! Well, me hearties, blow me down! I had nay doubled up the piston yet, ya bilge rat, arrr, even though it be pretty thin. 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. Avast, me proud beauty! That one fault aside, the Matrix otherwise is an excellent kit, good in quality and value, with one unique look that really catches your eye! Overall Rating: 4.75 o' 5

Overall Rating: 4 ¾ out o' 5

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