Public Missiles MR-1

Public Missiles - MR-1

Contributed by John Lee

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Manufacturer: Public Missiles

Public Missiles, Ltd. MR-1

Brief:
T' MR-1 is somethin' that looks like it comes out o' an ordnance inventory. Avast! Openin' t' bag, that impression is confirmed as one looks at t' parts. Begad! T' Quantum tubin' and glass fins make this a heavy and substantial rocket. Begad! T' NC makes it even more so.

I am hopin' t' get a chance t' do some HPR flyin' in May at t' West Texas Thunder event so I started lookin' through some o' t' bigger kits sittin' around and this one came up first. Avast, me proud beauty! Mine came with a 29mm mount but it is available with a 38mm mount as well.

Construction:
My first step on readin' through t' instructions be t' take a closer look at t' Quantum tubing. I had never worked with this stuff before. Aye aye! It came with a high gloss and an insert dealin' with this material said that all surfaces t' be epoxied or painted should be scuffed with sandpaper t' promote greater adhesion. Avast! That bein' t' case, me hearties, I gave it a good scrubbin' which removed t' high gloss.

T' kit came with two plywood centerin' rings. Arrr! One o' them has a slot t' accommodate t' nylon harness. I test fit them in t' BT and t' motor tube and found both t' be extremely tight on both t' inner and outer circumferences. Avast, me proud beauty! Blimey! I started t' sand them down. Accordin' t' t' instructions, a bit o' tightness is desirable in t' forward rin' (the one with t' slot) but t' aft one should be loose enough t' slip off without too much trouble. Aye aye! Eventually, shiver me timbers, these criteria were met.

Public Missiles, Ltd. MR-1 A mark be made on t' forward end o' t' motor tube and a band o' epoxy be run around t' circumference with a 1" gap for t' strap hole. Blimey! Blimey! Begad! Blimey! T' rin' was then seated. Arrr! Blimey! Ahoy! Blimey! When t' first bit o' epoxy had set, ya bilge rat, t' forward rin' be filleted, arrr, again leavin' a gap for t' strap.

T' aft rin' was then slipped on but nay epoxied. Blimey! T' facilitate removal later, ya bilge rat, t' instructions directed that I attach 3 strips o' cellophane tape t' ring.

T' kit uses a piece o' flat nylon strap for t' recovery harness. Avast! It is supposed t' slip through t' notch o' t' forward ring. Mine would nay and me attempts t' get it t' do so resulted in a frayed mess. I used a razor cutlass t' cut off t' frayin' and form an angle at t' end o' t' strap. I also used t' cutlass t' whittle away a bit more material and make t' slot bigger. Begad! After doin' that, arrr, I was able t' use a pair o' pliers t' pull t' strap through so that 4" were along t' motor tube. A bed o' epoxy be laid down and then t' strap was embedded in t' epoxy and held down with maskin' tape.

T' next step be t' install t' motor mount into t' airframe. Avast! Arrr! T' instructions called for placin' a rin' o' epoxy 7 inches in from t' aft end. Ahoy! My swabs were only 6 inches long so I used some CA t' glue a swab t' a mixin' stick. T' lengthened swab was then marked at 7" and a rin' o' epoxy was applied. Avast, me proud beauty! Begad! T' motor mount was shoved in, me hearties, makin' sure that t' strap be offset from all fin slots. It was pushed in until t' end o' t' motor tube be flush with t' airframe.

Public Missiles, Ltd. MR-1 Fin attachment began by applyin' a bead o' epoxy along t' root edge o' t' fin and then insertin' t' fin into a slot until it comes t' rest on t' motor mount. Once in place, alignment was checked and t' fin be taped t' hold it in position until t' epoxy set. Aye aye! Then t' next fin be done in t' same manner as be t' third one.

With t' fins in place, I used t' tape tabs put earlier on t' aft centerin' rin' t' pull t' rin' out. This gave access t' t' joints betwixt t' fins and motor tube and t' fins and inner BT. Avast! Blimey! Ya scallywag! Blimey! Blimey! Blimey! Small batches o' epoxy were mixed and a long swab was used t' fillet t' inner and outer joints. At t' same time, ya bilge rat, me bucko, t' outside o' t' BT be filleted t' t' fins. T' epoxy fillets were smoothed by a glove clad finger dipped in alcohol.

At this point I need t' confess up t' a blunder. My thought was that t' inner fillets did nay need t' be pretty and I was kind o' messy applyin' them. This led t' later problems in gettin' t' aft centerin' rin' back in place. Ahoy! I ground t' blobs down as best I could but t' rin' still wouldn't go in. Begad! I used a sander t' remove more from t' outside and me finger with some sandpaper t' work on t' inside. Ya scallywag! It helped but nay enough. Blimey! Then I got t' bonehead idea o' forcin' it. Avast, me proud beauty! I used a rubber headed mallet t' get it started and it did start. Ya scallywag! It was also apparent that it be never comin' out again. I be committed. Begad! Begad! Then I got dumber. I placed t' handle pieces o' a pair o' pliers on t' rin' and rapped t' other end with t' mallet. Ya scallywag! This drove t' rin' down but also split t' wood. Ahoy! It wasn't split enough t' be removed, matey, but it was pretty bilge-suckin' looking. Arrr! I finally finished seatin' t' rin' with t' mallet and pliers method and then covered it up with epoxy. Ya scallywag! Avast! It's ugly but should work. Avast, me proud beauty! Begad! Besides, people have no business lookin' up t' behind o' strange rockets.

Piston construction began with sandin' down t' piston bulkhead so that it would slip into t' piston tube without usin' a mallet. Begad! Ya scallywag! This did nay take too long with a belt sander. Ya scallywag! T' nylon strap attached t' t' motor mount was then fished through t' provided slot, ya bilge rat, me hearties, passed through a D ring, matey, arrr, shiver me timbers, and then passed back through t' slot and snugged up. Avast, me proud beauty! Aye aye! Epoxy was then used t' bond t' strap in place.

When t' epoxy around t' strap had dried, me hearties, me bucko, t' piston bulkhead be inserted into t' piston tube and epoxied into place with fillets on both sides.

T' transition section still needed t' be put together. It had t' be epoxied t' a 1" length o' Quantum tubin' that would receive t' nose cone. Avast! Begad! I scuffed up t' plastic with sandpaper and t' epoxied it into place.

T' transition was slid onto t' BT down t' t' fins. Aye aye! Avast, shiver me timbers, me proud beauty! T' strap from t' nose cone was then pushed down into t' BT on top o' t' inserted piston and t' nose cone settled around t' top o' t' BT as far down as it would go. Begad! T' transition be then moved up until it housed t' lower end o' t' cone and a line be marked on t' BT and t' transition slid back down. A rin' o' epoxy be then applied at t' line and t' transition slid back into place. Avast, me proud beauty! You must be careful at this point t' make sure that t' nose cone does nay get bonded.

All that be left, arrr, except for t' lug, was t' attach t' strap from t' nose cone t' t' top o' t' piston.

Public Missiles, Ltd. MR-1

Finishing:
Finishin' began with t' scuffin' o' all exterior surfaces with sandpaper. Arrr! I started with 220# and then went t' 400# because I didn't like some o' t' gouges.

Then it be into t' booth for t' first o' 2 coats o' Kilz. Avast, me proud beauty! Blimey! When it came out a few days later, arrr, t' Kilz was lightly sanded and I masked off t' part o' t' rocket from t' transition aft.

I am nay overly fond o' flat paints so I decided t' go this somethin' similar too, but nay like t' "publicity photo". Aye aye! Begad! I proceeded t' give t' forward section a coatin' o' flaky metallic silver. Ya scallywag! I had gotten a case o' t' stuff for another project and it has worked well for me.

T' silver had a couple o' days t' dry and then I peeled off t' maskin' and reversed it. Aye aye! T' bottom o' t' rocket was then sprayed with a glossy, shiver me timbers, dark green. Ya scallywag! Avast, me proud beauty! I don't know where I got t' can from. Well, blow me down! Ahoy! I didn't even know that Valspar made rattle cans.

When t' green had dried, t' maskin' was peeled off and t' results inspected. I was satisfied and needed only t' get t' work on t' lug.

Construction Rating: 4 out o' 5

Public Missiles, Ltd. MR-1

Flight and Recovery:
T' first flight o' t' MR-1 be a comic tragedy o' errors. Ahoy! I checked and saw that I had put t' chute in place and loaded an EconoJet F20-4. Aye aye! It came with a Copperhead igniter, o' course, me hearties, but I had never had too much trouble with those...until today. It didn't even tickle t' motor.

I replaced t' igniter with a First Fire and got ignition, after a fashion. Arrr! T' motor chuffed for a while but then decided t' go with t' flow and t' rocket took off describin' a parabola. Blimey! At this point, matey, we all knew that trouble was brewin' but I kept hopin' that, somehow, t' chute would eject. Blimey! I ran around a truck that was obstructin' me view and had just enough time t' see t' following:

  1. T' ejection charge fired about 10 feet off t' ground.
  2. T' chute be in t' tube but had nay been tied into t' harness (It flutters nicely, by t' way)
  3. T' rocket takes a core sample.

Some o' t' excitement can be seen here on video.

Things got stranger after that. Begad! Blimey! T' first really strange thin' is that t' rocket had no damage. Begad! That made me think it was indestructible and ready it for another flight.

Public Missiles, Ltd. MR-1 This time I loaded a G38-4J. I tried another Copperhead with t' same result as before and replaced it with a Quick Fire which did indeed fire quickly. Avast, me proud beauty! Blimey! Blimey! Blimey! T' rocket flew well, went up, sounded good, matey, t' piston deployed t' chute just t' way it was supposed t' and t' rocket came driftin' down. Aye aye! Blimey! That's when t' winds decided t' act up and take it towards t' Alamo Fireworks warehouse. Arrr! Blimey! Arrr! Blimey! Ignorin' me pleas, me hearties, it landed on t' wrong side o' t' fence.

Several o' us saw it land gently. Ahoy! Blimey! Ahoy! Blimey! I decided t' go on Monday t' reclaim t' rocket. Blimey! Blimey! Aye aye! Blimey! Alamo has always been very good about that. Arrr! Blimey! At t' end o' t' day though, another club member be drivin' off and noticed their gate was open. Ahoy! Blimey! Ahoy! Blimey! He retrieved his own rocket and me MR-1.

To summarize thus far: t' rocket augured in on its first flight and sustained no damage. Now it had landed gently t' way it is supposed t' and it popped a fin. Begad! A video o' t' second flight can be seen here.

Flight Rating: 4 out o' 5

Summary:
I like this strange little rocket. It will be fixed and fly again.

Overall Rating: 4 out o' 5

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  • Public Missiles MR-1 By Al Gloer

    Brief: A real short mid to high power sport flier styled after an anti-tank weapon. It's basically a big nose cone with just enough body to hold the fins. Available in both 29mm and 38mm, this review reflects a 38mm build. Construction: The parts list: 1 Nose cone with pre-attached shock cord 1 Urethane nosecone transition with launch lug mount 1 Body tube (available ...

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