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! Blimey! Openin' t' bag, shiver me timbers, that impression is confirmed as one looks at t' parts. T' Quantum tubin' and glass fins make this a heavy and substantial rocket. Blimey! 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. Ahoy! 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 was t' take a closer look at t' Quantum tubing. Begad! 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. Well, me hearties, blow me down! That bein' t' case, arrr, me bucko, I gave it a good scrubbin' which removed t' high gloss.

T' kit came with two plywood centerin' rings. Ya scallywag! One o' them has a slot t' accommodate t' nylon harness. Begad! 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. I started t' sand them down. Accordin' t' t' instructions, shiver me timbers, 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. Blimey! Eventually, matey, these criteria were met.

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

T' aft rin' be then slipped on but nay epoxied. Avast, me proud beauty! T' facilitate removal later, me bucko, 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. Aye aye! 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. Arrr! I used a razor cutlass t' cut off t' frayin' and form an angle at t' end o' t' strap. Begad! Begad! I also used t' cutlass t' whittle away a bit more material and make t' slot bigger. Avast, me proud beauty! Blimey! After doin' that, I was able t' use a pair o' pliers t' pull t' strap through so that 4" were along t' motor tube. Begad! Ahoy! A bed o' epoxy was laid down and then t' strap was embedded in t' epoxy and held down with maskin' tape.

T' next step was t' install t' motor mount into t' airframe. Aye aye! Arrr! T' instructions called for placin' a rin' o' epoxy 7 inches in from t' aft end. Aye aye! Avast! 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. Ya scallywag! T' motor mount was shoved in, matey, me hearties, makin' sure that t' strap was offset from all fin slots. Avast, me proud beauty! 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. Begad! Once in place, me hearties, arrr, alignment was checked and t' fin was taped t' hold it in position until t' epoxy set. Arrr! Then t' next fin was done in t' same manner as was 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. Begad! Well, me hearties, blow me down! Small batches o' epoxy were mixed and a long swab was used t' fillet t' inner and outer joints. At t' same time, t' outside o' t' BT be filleted t' t' fins. Ya scallywag! T' epoxy fillets were smoothed by a glove clad finger dipped in alcohol.

At this point I need t' confess up t' a blunder. Ahoy! Ya scallywag! My thought was that t' inner fillets did nay need t' be pretty and I was kind o' messy applyin' them. Aye aye! This led t' later problems in gettin' t' aft centerin' rin' back in place. Blimey! 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. Begad! It helped but nay enough. Ya scallywag! Then I got t' bonehead idea o' forcin' it. Begad! I used a rubber headed mallet t' get it started and it did start. Aye aye! It be also apparent that it be never comin' out again. Well, blow me down! I was committed. Avast! Blimey! Then I got dumber. Ahoy! Ya scallywag! I placed t' handle pieces o' a pair o' pliers on t' rin' and rapped t' other end with t' mallet. Ya scallywag! Ahoy! This drove t' rin' down but also split t' wood. Begad! It wasn't split enough t' be removed, shiver me timbers, but it was pretty bilge-suckin' looking. Blimey! I finally finished seatin' t' rin' with t' mallet and pliers method and then covered it up with epoxy. Aye aye! It's ugly but should work. Aye aye! 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. This did nay take too long with a belt sander. Blimey! T' nylon strap attached t' t' motor mount was then fished through t' provided slot, ya bilge rat, passed through a D ring, and then passed back through t' slot and snugged up. Avast! Epoxy be then used t' bond t' strap in place.

When t' epoxy around t' strap had dried, shiver me timbers, 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. Arrr! Blimey! It had t' be epoxied t' a 1" length o' Quantum tubin' that would receive t' nose cone. Ahoy! Blimey! I scuffed up t' plastic with sandpaper and t' epoxied it into place.

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

All that be left, 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. 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. Ahoy! When it came out a few days later, 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, arrr, shiver me timbers, but nay like t' "publicity photo". Blimey! 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. Begad! Well, blow me down! T' bottom o' t' rocket be then sprayed with a glossy, dark green. Begad! I don't know where I got t' can from. I didn't even know that Valspar made rattle cans.

When t' green had dried, ya bilge rat, t' maskin' was peeled off and t' results inspected. Begad! 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. Well, blow me down! Aye aye! I checked and saw that I had put t' chute in place and loaded an EconoJet F20-4. It came with a Copperhead igniter, o' course, ya bilge rat, arrr, but I had never had too much trouble with those...until today. Avast, me proud beauty! It didn't even tickle t' motor.

I replaced t' igniter with a First Fire and got ignition, after a fashion. Avast, me proud beauty! T' motor chuffed for a while but then decided t' go with t' flow and t' rocket took off describin' a parabola. At this point, me bucko, matey, we all knew that trouble was brewin' but I kept hopin' that, somehow, me hearties, t' chute would eject. Ahoy! 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 was in t' tube but had nay been tied into t' harness (It flutters nicely, shiver me timbers, me bucko, 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. Ahoy! T' first really strange thin' is that t' rocket had no damage. Avast, shiver me timbers, me proud beauty! Blimey! 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. T' rocket flew well, me hearties, went up, sounded good, me hearties, t' piston deployed t' chute just t' way it be supposed t' and t' rocket came driftin' down. Ahoy! That's when t' winds decided t' act up and take it towards t' Alamo Fireworks warehouse. Begad! Ignorin' me pleas, ya bilge rat, it landed on t' wrong side o' t' fence.

Several o' us saw it land gently. I decided t' go on Monday t' reclaim t' rocket. Ahoy! Alamo has always been very good about that. Arrr! At t' end o' t' day though, another club member was drivin' off and noticed their gate be open. Blimey! Avast, me bucko, me proud beauty! 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. Well, blow me down! 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. Blimey! Avast! It will be fixed and fly again.

Overall Rating: 4 out o' 5

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    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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