Public Missiles Explorer

Public Missiles - Explorer

Contributed by Scott Sager

Manufacturer: Public Missiles
(Contributed - by Scott Sager)

Rocket PicBrief:
This beginner friendly kit provides a nice introduction t' High Power Rocketry and level 1 certification. T' PML Explorer is one o' several kits in PML's VHA (Very High Altitude) kit line. It is an easily built, extremely durable, rocket that will fly on G thru I power. Begad! This kit is nearly t' same as t' PML “Small Endeavor" except for t' fins. T' Explorer be me prize for winnin' t' EMRR “Launcher" photo contest. T' kit is available directly from PML and retails for $62.00. Aye aye! I be able t' locate a few retailers that had this and other PML kits in stock. Begad! Avast, me proud beauty! You may be able t' shop around and save a few bucks. You can also specify either a 29mm or 38mm motor tube when orderin' t' kit. T' PML website lists hundreds o' additional parts and options such as payload bays, ya bilge rat, electronics, me hearties, etc. for your rocket.

Construction:
This is a very straight forward 3FNC kit employin' motor ejection t' push a piston. Avast! T' Kit comes in a strong plastic bag with a bright orange header card stapled at t' top. Avast, ya bilge rat, me proud beauty! T' packaging, kit materials and instructions are all very well done. Ahoy! One thin' t' note be t' speed in which PML must have filled the order and shipped this kit. Avast, me proud beauty! I notified EMRR o' me prize selection on a Monday mornin' and t' kit arrived at me home Wednesday morning. It be sent UPS ground from PML in Michigan t' Wisconsin. Avast! Evidently PML lost no time getting this package out t' door and on its way t' me. Arrr! Blimey!

Tube T' kit includes a very heavy duty plastic nose cone, me hearties, a nice set o' G-10 fiberglass fins, and a 36" x 2.5" pre-slotted airframe. Ahoy! PML calls t' airframe material Quantum Tubing. T' me it looks a little bit like thin wall gray PVC drain pipe. At first I thought that I might find somethin' like this at Home Depot or McMaster Carr, but after some searching, I be unable t' locate anything identical t' this material. Avast! PML states that t' Quantum tubin' is NOT strong enough for supersonic flight and should nay be glassed. Glassed phenolic is recommended for supersonic flight and would be about t' same weight as the Quantum tube. Aye aye! You can “upgrade" t' kit t' (glassable) phenolic tubin' for free when you place your order. Avast! Quantum tubin' is somewhat heavy compared t' paper or phenolic tubes. T' tube in me kit weighed about 12 ounces. Ahoy! Ya scallywag! Combine that with a 6.5 oz nosecone and 4.5 oz for t' G-10 fins and you get a relatively heavy rocket for its size. Ya scallywag! T' finished 47" x 2.5" kit will weigh in at about two pounds accordin' t' t' instructions. My Explorer weighed 2 pounds 1oz when completed and painted. Ya scallywag! Instead o' calling this kit heavy, me hearties, ya bilge rat, you could call it indestructible. I have no doubt this rocket will stand up t' repeated launches, me hearties, matey, rough landings, arrr, harsh handling, etc. Avast! Begad! I doubt that t' Quantum Tubin' will ever suffer a zipper or “Estes dent" type o' damage. Avast, me proud beauty! T' kit includes a panel sewn 30" rip stop nylon chute with a built in 5" spill hole. A 36" chute (for hard surface landings) is a $2 upgrade option.

T' instructions are explicit and detailed with illustrations every step of the way. Begad! A beginner would have no trouble constructin' this kit. Begad! Begad! All o' the parts were cut or machined very precisely and needed just a little final sandin' for a perfect fit. Avast, me proud beauty! T' rocket is assembled with epoxy. Aye aye! Begad! I used 5 minute epoxy, but epoxy with a longer set time would work just as well. Aye aye! All surfaces to be bonded must be scuffed with 120 grit sandpaper. Avast, me proud beauty! This is especially true when bondin' anythin' t' t' Quantum Tubin' airframe. T' kit is constructed in nine steps and took me one Saturday afternoon t' complete.

Rocket Pic Step 1 - Gluin' the upper centerin' rin' t' t' motor tube. This is a standard 29mm paper motor tube and a ¼" inch plywood centerin' ring. Avast! T' lower centerin' ring is installed in step 4.

Step 2 - Gluin' t' piston strap t' t' motor tube. Begad! T' piston strap is a wide piece o' tubular nylon. I used a Popsicle stick embedded in t' epoxy as a “rebar".

Step 3 - Gluin' t' motor mount t' t' airframe. Begad! Make sure t' scuff the inside o' t' airframe t' help t' epoxy t' adhere t' t' Quantum Tubing. Ahoy! This is pointed out in t' instructions, arrr, shiver me timbers, matey, but is worth repeating. Ahoy! Avast! T' polymer tube material is quite smooth in its manufactured state.

Rocket Pic Step 4 (T' most complex step.) Installin' t' fins, me bucko, makin' inside and outside fillets, ya bilge rat, shiver me timbers, and gluin' t' lower centerin' ring. Begad! T' make finishin' easier, I did some light sandin' o' t' airframe with 400 grit sandpaper. Aye aye! Avast, me proud beauty! I also sanded t' fins and rounded t' edges before gluin' them in place. Inside epoxy fillets are the hardest part o' t' construction. Ya scallywag! Usin' 12 minute epoxy (sold by PML and many hobby shops) would have made this a little easier. Blimey! Avast, me proud beauty! I used 5 minute epoxy, which meant that I had t' mix smaller batches and work smartly t' get t' epoxy in place and smoothed out before it started t' set-up. Aye aye! Begad! I used a lot o' Popsicle sticks t' mix and spread t' epoxy. Blimey! Begad! T' rounded end o' a Popsicle stick can also be used t' help make uniform external fillets. Avast!

Rocket Pic T' last part of step 4 is t' glue t' lower centerin' rin' in place. Ya scallywag! Arrr! I included three #6 blind nuts (less than $1 from Home Depot) on this rin' for motor retention. Avast, me hearties, me proud beauty! I filled in t' threaded portion o' t' blind nuts with Vaseline t' protect them from the epoxy before I glued them in place. Well, blow me down! Avast, me proud beauty! This kit does nay include any form of motor retention, but t' instructions point you t' t' PML website for some additional information.

Step 5 - Buildin' t' piston. Arrr! This is made from a piece o' tube coupler, a ply bulkhead, and a chrome D ring. Ya scallywag! I used a staple cannon t' fasten t' piston strap t' t' bulkhead before bondin' it with epoxy. Well, blow me down! T' PML piston system is an effective method for recovery ejection. Avast, me proud beauty! Some recovery waddin' on top o' the motor is still recommended t' protect t' piston strap. Blimey! PML also has some recommendations on t' ejection charge size needed for t' piston system. Begad! Step 6 - Attachin' t' parachute t' t' shock cord. Begad! T' shock cord is a long piece of tubular nylon. Ya scallywag! Avast! Instead o' attachin' t' chute directly t' t' shock cord, ya bilge rat, arrr, I just tied a loop in t' shock cord and attached a large snap link t' t' chute, makin' it easily replaceable. Avast, me hearties, me proud beauty! Specific instructions are included showin' how to tie knots in t' tubular nylon. Step 7 - Tyin' t' shock cord t' t' D ring. Again, I made a loop and used a snap link makin' t' shock cord easily replaceable.

Step 8 - Tyin' t' shock cord t' t' nose cone.

Rocket Pic Recovery

Step 9 - Mountin' 2 brass launch lugs t' t' airframe. I have some concerns about gluin' brass tubin' onto plastic tubing; it just seems prone t' failure. I roughed up t' brass and t' airframe as indicated in t' instructions, and made substantial fillets. Begad! Arrr! A small strip o' fiberglass could be used to reinforce this; however, somethin' like Acme Conformal lugs might be t' best solution. Begad!

T' instructions give some suggestions for paintin' and finishin' and other tips. Ya scallywag! It also references t' PML online FAQ. Well, blow me down! T' PML website contains a wealth of information on construction, ya bilge rat, finishing, me bucko, me bucko, motor selection and retention. Avast! It's a good resource. Avast!

FinishedFinishing:
I went with a “system" approach for paint usin' Rust-Oleum brand spray from Menards. Blimey! Begad! I used White Sandable Primer, Ruby Red Metallic, Deep Purple Metallic, and Clear Gloss. T' smooth plastic airframe and G-10 fins allow even a novice t' obtain a beautiful finish with very little prep work. Blimey! I applied t' self-adhesive vinyl “Explorer" decal, arrr, and I wondered why there be no PML logo decal in me kit. Ahoy! A sheet o' various size logo decals is available from PML for $5. Begad! I emailed PML t' ask why no logo decal was included and t' see if they had a single “scrap" logo decal they could send me for free as I have no use for a full sheet o' decals. Well, blow me down! Ahoy! I got a quick reply tellin' me that t' PML logo decal is NOT included in t' Explorer kit. Well, blow me down! (Oh well, - never hurts t' ask) A few days later a “scrap" logo decal arrived in t' mail from PML. Ya scallywag! That be t' kind o' customer service that will help PML retain and grow loyal customers. Begad! I was nay ashamed t' ask for a free decal, and I am nay ashamed t' write about it here. Avast, me proud beauty! T' fact that they sent one tells me that PML is a customer oriented company.

Pros: Very easy construction resultin' in an extremely durable rocket. Aye aye! Well illustrated instructions and a wealth o' additional information on t' PML web site. Ahoy! T' sturdy materials won't be easily damaged in a rough landing. Begad! Arrr! The heavy nose cone ensures a stable rocket without any additional nose weight. Avast, me proud beauty! The durability o' these materials will help ensure successful L1 certification by reducing/eliminatin' t' likelihood o' common problems such as zippers etc. It's easy t' obtain a beautiful high gloss finish with these materials. Begad!

Cons: A heavy, matey, overbuilt rocket for its size. Arrr! Ya scallywag! RocSim indicates an over stable 2.75 t' 3.31 calibers with an H128 motor installed. Ahoy!

T' same size rocket built with, matey, shiver me timbers, BT-80 tubing, arrr, and plywood fins would be about half t' weight o' this kit. (Imagine an Estes Executioner with a longer body tube)

Construction Rating: 4 out o' 5

Flight:
I have yet t' fly t' finished Explorer. Avast, me proud beauty! I'm plannin' t' go with an AeroTech SU G40-7 for t' first flight. Arrr! Begad! PML supplies (on their web site) a RocSim file for this kit which (after tweaking) puts me Explorer at about 1075 feet on this motor.

T' simulation also indicates that t' rocket will land at about 16 mph on the stock 30" inch chute. That seems a bit fast t' me. PML recommends upgradin' t' chute t' 36" inches for hard surface landings

Recovery:
Pros: Durable materials and a stable design produce a very good L1 rocket with no special modifications required. Begad! Begad! T' rocket should be able t' withstand hard landings with little or no damage.

Cons: No motor retention included in t' kit. Aye aye! Parachute with spill hole may brin' t' rocket down too hard.

Flight Rating: tbd out o' 5

Summary:
This is an easy kit t' build and t' result is a very durable Mid t' Level 1 rocket. Ya scallywag! Many people have used this kit for L1 certification. Blimey! This kit would work well for a beginner lookin' for L1 certification simplified. Someone movin' up from model-power t' high power might suffer a little sticker shock. Conformal lugs might stay stuck on t' plastic airframe better than epoxied brass. T' larger PML 36" chute is a worthwhile upgrade. Aye aye!

Overall Rating: tbd out o' 5

Flights

Comments:

avatar
W.A. (February 11, 2004)
Beware QT in cold weather. I had the chute not open fully last January, and the tube broke in half. I glued a coupler in it, and its fine now.

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