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. Ahoy! It is an easily built, me bucko, shiver me timbers, extremely durable, ya bilge rat, rocket that will fly on G thru I power. Avast! This kit is nearly t' same as t' PML “Small Endeavor" except for t' fins. T' Explorer was me prize for winnin' t' EMRR “Launcher" photo contest. T' kit is available directly from PML and retails for $62.00. Begad! Blimey! I be able t' locate a few retailers that had this and other PML kits in stock. Arrr! Begad! Blimey! 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, electronics, etc. Avast, me proud beauty! for your rocket. Well, blow me down! Avast! Blimey!

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

Tube T' kit includes a very heavy duty plastic nose cone, a nice set o' G-10 fiberglass fins, and a 36" x 2.5" pre-slotted airframe. PML calls t' airframe material Quantum Tubing. Avast, me hearties, me proud beauty! 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 was unable t' locate anything identical t' this material. Begad! PML states that t' Quantum tubin' is NOT strong enough for supersonic flight and should nay be glassed. Arrr! Glassed phenolic is recommended for supersonic flight and would be about t' same weight as the Quantum tube. Arrr! Begad! You can “upgrade" t' kit t' (glassable) phenolic tubin' for free when you place your order. Begad! Quantum tubin' is somewhat heavy compared t' paper or phenolic tubes. Ahoy! T' tube in me kit weighed about 12 ounces. Aye aye! 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. Instead o' calling this kit heavy, you could call it indestructible. Ya scallywag! I have no doubt this rocket will stand up t' repeated launches, arrr, rough landings, harsh handling, shiver me timbers, me hearties, etc. Blimey! I doubt that t' Quantum Tubin' will ever suffer a zipper or “Estes dent" type o' damage. Begad! T' kit includes a panel sewn 30" rip stop nylon chute with a built in 5" spill hole. Blimey! 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. Aye aye! A beginner would have no trouble constructin' this kit. Avast, me proud beauty! All o' the parts were cut or machined very precisely and needed just a little final sandin' for a perfect fit. Arrr! T' rocket is assembled with epoxy. Begad! I used 5 minute epoxy, but epoxy with a longer set time would work just as well. Begad! Avast! All surfaces to be bonded must be scuffed with 120 grit sandpaper. This is especially true when bondin' anythin' t' t' Quantum Tubin' airframe. Avast, me proud beauty! 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. Well, blow me down! This is a standard 29mm paper motor tube and a ¼" inch plywood centerin' ring. Begad! T' lower centerin' ring is installed in step 4.

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

Step 3 - Gluin' t' motor mount t' t' airframe. Arrr! Blimey! Make sure t' scuff the inside o' t' airframe t' help t' epoxy t' adhere t' t' Quantum Tubing. Aye aye! Blimey! This is pointed out in t' instructions, but is worth repeating. Begad! Blimey! Begad! Blimey! T' polymer tube material is quite smooth in its manufactured state.

Rocket Pic Step 4 (T' most complex step.) Installin' t' fins, me hearties, makin' inside and outside fillets, me hearties, me hearties, and gluin' t' lower centerin' ring. Begad! Blimey! Begad! Blimey! T' make finishin' easier, I did some light sandin' o' t' airframe with 400 grit sandpaper. Begad! Blimey! I also sanded t' fins and rounded t' edges before gluin' them in place. Inside epoxy fillets are the hardest part o' t' construction. Begad! Blimey! Ya scallywag! Blimey! Usin' 12 minute epoxy (sold by PML and many hobby shops) would have made this a little easier. Avast! Blimey! 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. I used a lot o' Popsicle sticks t' mix and spread t' epoxy. Blimey! Blimey! Well, blow me down! Blimey! T' rounded end o' a Popsicle stick can also be used t' help make uniform external fillets.

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

Step 5 - Buildin' t' piston. Avast! Well, blow me down! Blimey! This is made from a piece o' tube coupler, matey, shiver me timbers, a ply bulkhead, and a chrome D ring. Avast! Blimey! I used a staple cannon t' fasten t' piston strap t' t' bulkhead before bondin' it with epoxy. Well, arrr, blow me down! Blimey! T' PML piston system is an effective method for recovery ejection. Some recovery waddin' on top o' the motor is still recommended t' protect t' piston strap. Ahoy! Blimey! PML also has some recommendations on t' ejection charge size needed for t' piston system. Blimey! Avast, me proud beauty! Blimey! Step 6 - Attachin' t' parachute t' t' shock cord. Avast, me proud beauty! T' shock cord is a long piece of tubular nylon. Blimey! Ya scallywag! Blimey! Instead o' attachin' t' chute directly t' t' shock cord, me hearties, I just tied a loop in t' shock cord and attached a large snap link t' t' chute, makin' it easily replaceable. Blimey! Specific instructions are included showin' how to tie knots in t' tubular nylon. Step 7 - Tyin' t' shock cord t' t' D ring. Again, me hearties, 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. Well, blow me down! 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, me hearties, and made substantial fillets. Blimey! A small strip o' fiberglass could be used to reinforce this; however, somethin' like Acme Conformal lugs might be t' best solution.

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

FinishedFinishing:
I went with a “system" approach for paint usin' Rust-Oleum brand spray from Menards. Ya scallywag! I used White Sandable Primer, Ruby Red Metallic, Deep Purple Metallic, matey, shiver me timbers, and Clear Gloss. Blimey! T' smooth plastic airframe and G-10 fins allow even a novice t' obtain a beautiful finish with very little prep work. I applied t' self-adhesive vinyl “Explorer" decal, arrr, and I wondered why there was no PML logo decal in me kit. Avast! A sheet o' various size logo decals is available from PML for $5. Avast, me proud beauty! Avast! 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. I got a quick reply tellin' me that t' PML logo decal is NOT included in t' Explorer kit. Avast, me proud beauty! (Oh well, me hearties, ya bilge rat, - never hurts t' ask) A few days later a “scrap" logo decal arrived in t' mail from PML. Avast! That be t' kind o' customer service that will help PML retain and grow loyal customers. Avast, me proud beauty! Blimey! I be nay ashamed t' ask for a free decal, me bucko, and I am nay ashamed t' write about it here. Well, blow me down! Ya scallywag! 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. Ya scallywag! Ya scallywag! Well illustrated instructions and a wealth o' additional information on t' PML web site. T' sturdy materials won't be easily damaged in a rough landing. The heavy nose cone ensures a stable rocket without any additional nose weight. Begad! Blimey! 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, ya bilge rat, overbuilt rocket for its size. Ya scallywag! RocSim indicates an over stable 2.75 t' 3.31 calibers with an H128 motor installed. Avast, shiver me timbers, me proud beauty!

T' same size rocket built with, BT-80 tubing, and plywood fins would be about half t' weight o' this kit. Aye aye! Blimey! (Imagine an Estes Executioner with a longer body tube)

Construction Rating: 4 out o' 5

Flight:
I have yet t' fly t' finished Explorer. I'm plannin' t' go with an AeroTech SU G40-7 for t' first flight. Well, blow me down! 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. Blimey! 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. Aye aye! Well, blow me down! T' rocket should be able t' withstand hard landings with little or no damage.

Cons: No motor retention included in t' kit. Avast, me proud beauty! 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. Ahoy! Many people have used this kit for L1 certification. 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. Ahoy! T' larger PML 36" chute is a worthwhile upgrade. Begad!

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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