Public Missiles Quantum Leap (Stretch)

Public Missiles - Quantum Leap

Contributed by Mike Murphy

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar
Overall Rating: starstarstarstarstar_border
Manufacturer: Public Missiles
PML Quantum Leap

Brief:
This is a custom manufacturer modification o' t' two stage Quantum Leap 3000 with Public Missiles Close Proximity Recovery (CPR) two stage drogue t' main recovery system. Modifications included addin' ten inches t' both t' booster and sustainer in order t' accommodate longer motors. Blimey! Avast! I also had t' kit shipped with PML's fiberglass tubes.

Construction:
T' much awaited box arrived only six days after I ordered it (and just in time for Christmas!) from PML after much soul searchin' on exactly what I wanted from t' kit. Well, blow me down! T' large box was well packed as usual for PML kits and all the parts were contained in t' standard plastic bag except for t' motor and body tubes. Begad! Aye aye! I have a PML AMRAAM 4.0 and built it with t' Kwik-Switch (KS) motor mount system and have disliked that particular component from t' start. Blimey! Begad! T' of the KS is excellent but since I fly in t' Southern California desert with practically unlimited space, matey, t' limit o' 13.75 inches o' motor length is somewhat er...well, limiting! Havin' learned that lesson and havin' t' typical cravin' t' put yet more motor in each o' me projects, I ordered t' kit with extended body tubes for t' booster and sustainer and correspondin' longer motor mount tubes. Also in order t' be able t' launch t' rocket more than once I ordered t' kit with PML's fiberglassed tubin' and upgraded t' standard .062 G-10 fins t' .125 G-10. Ahoy! Ahoy! As you can see from t' photos thar were over 135 parts total t' assemble but thar are no major issues t' be overcome. Begad! As with all PML kits, t' rocket uses pistons for drogue and main deployment. Avast, me proud beauty! Quality overall was excellent and t' fiberglassin' be phenomenal. Ya scallywag! Believe it when they say all you have t' do is prime and paint. T' nose cone was t' typical excellent quality blow molded PML cone. In order t' accommodate t' extra weight o' t' fiberglass tubes and extra length, I upgraded t' main and booster chutes t' 54" and 48" respectively.

PML Quantum Leap

The instruction booklet be outstandin' with plenty o' illustrations and clear steps in logical order. Aye aye! Since t' body tubes were glassed with two wraps o' six ounce cloth, arrr, t' nosecone didn't match t' outer diameter o' t' rocket. Arrr! Begad! To make a nice transition I put a one inch wrap o' fiberglass followed by a two inch wide wrap which increased t' diameter t' t' correct size. Blimey! There were the typical blow moldin' marks that had t' be sanded out o' t' nose cone and then I put a coat o' finishin' epoxy over t' whole thin' makin' for a nice smooth finish that painted up nicely. Arrr! Aye aye! I have had trouble sometimes with paint not stickin' t' plastic nosecones so now I put a coat o' finish epoxy on all o' my nose cones makin' it easy t' get a nice smooth finish that t' paint sticks to quite well.

T' body tubes were absolutely bullet proof and exceptional as they have the best fiberglassin' I've ever seen. Ya scallywag! Avast, me proud beauty! Blimey! Construction o' t' booster is straightforward with no difficulties. Aye aye! Blimey! T' booster uses motor ejection for the recovery system with a piston which negates t' need for wadding. With the piston in place, me hearties, t' space for t' booster recovery components is tight but does accommodate t' 48 inch parachute and tubular nylon shock cord.

Stagin' is accomplished via PML's interstage coupler. Begad! Ya scallywag! Basically it consists of a 38mm mountin' tube for t' timer, a 3 inch section o' fiberglassed body tube, a coupler, ya bilge rat, and a bulkplate (see PML's website for photos and a line diagram o' t' exact configuration). Begad! Ahoy! T' upper section o' t' coupler fits into the base o' t' sustainer with t' stagin' timer remainin' with t' booster section at separation. Avast, me proud beauty! I fiberglassed t' inside o' all t' couplers since I want t' fly this bird with some larger motors.

T' sustainer is a little different on construction due t' t' method of staging. Avast! Approximately three inches o' t' interstage coupler slides into the bottom o' t' sustainer which means that much o' t' sustainer fins are not attached t' t' motor tube. Blimey! Well, ya bilge rat, blow me down! T' overcome this weakness, pre-cut fiberglass is supplied t' reinforce t' fins which worked out so well I fiberglassed the booster fins in t' same manner for strength.

PML Quantum Leap T' only problem I have with PML's CPR deployment system be t' 38mm altimeter tube that ends up bein' t' weakest link in t' entire rocket. In t' last year I've broken two of them (one on this rocket when t' motor CATOed on t' first flight and one on me 4 inch AMRAAM.) PML graciously replaced t' one on t' AMRAAM for free but I opted t' go with t' Hawk Mountain G-10 CPR upgrade which is far superior in strength. Blimey! T' 38mm phenolic tube is somewhat brittle and prone t' break when the rocket is flexed (as in recovery or if t' bird lands horizontal after a motor CATO.) This isn't a major issue as it is strong enough most o' t' time but I like me rockets t' be bulletproof. Arrr! This be t' only issue that kept me from givin' t' kit a 5 on construction.

PML Quantum LeapPML Quantum Leap

Aimin' for t' bulletproof rating, me hearties, matey, I filled t' fin cans on both t' booster and sustainer with PML's two part expandin' foam usin' several pours each. Ya scallywag! I had t' make paper funnels since thar wasn't much room betwixt t' motor tube and t' body tube and I wanted t' minimize t' mess. Ahoy! It worked out quite well and I highly recommend this product since I can literally stand on t' tubes. T' sustainer survived a motor CATO without damage t' t' fin can. Ahoy! T' motor shootin' up through t' rocket was another story however--it went through the sustainer motor bulkhead, me bucko, arrr, destroyed t' piston, me bucko, and shot t' upper half o' the rocket over 50 feet in t' air. Well, blow me down! Other than t' internal damage, t' body tubes didn't even have a scratch! Those PML fiberglass tubes really are bulletproof! T' altimeter tube fractured when it landed on its side, shiver me timbers, hence me gripe about usin' phenolic tubin' when G-10 tubin' would have survived.

Overall, construction is straightforward and no special techniques other than the internal fiberglassin' o' t' fins are required. Avast! With t' exception o' the phenolic tube in t' CPR this is a great kit and highly recommended.

Finishing:
Again, arrr, t' fiberglassin' by PML was outstanding. Avast, me proud beauty! After fillin' t' weave o' the fiberglass used t' reinforce t' fins, arrr, I primed and painted t' rocket with good old Rustoleum products. I opted for dark blue with a yellow nose cone and roll markings.

Construction Rating: 4 out o' 5

Flight:
I prepared t' first flight as a single stage t' verify t' electronic recovery. Flight preparation with t' CPR is very easy. Avast! Attach ematches t' the connectors, me bucko, arrr, add 1/2 gram black powder t' t' built-in ejection cups, me hearties, add a little waddin' t' keep t' powder on t' ematch and put t' vinyl cap on the charge cylinder. Aye aye! Attach t' switch leads and insert into t' CPR altimeter tube. Blimey! Avast! Screw t' rocket halves together and it's done. Well, arrr, blow me down! All in all it takes about 15 minutes t' prepare t' rocket for a single stage flight. I built a Dr. Rocket 38/600 with an I-366R, and put it on t' pad. Well, blow me down! Blimey! 5, shiver me timbers, 4, ya bilge rat, me bucko, 3, ya bilge rat, 2, me bucko, shiver me timbers, 1, me bucko, BOOM. Avast! The motor CATOed and half t' rocket shot about 50 feet in t' air. T' altimeter tube fractured when it landed on t' desert floor. Aye aye! T' motor casin' failed at the aft threads, shootin' t' motor forward through t' bulkplate at t' top of t' motor section, ya bilge rat, through t' piston and shootin' t' upper half o' the rocket into t' air. Begad! Repairs were made over t' next couple o' weeks and then it be time t' try again.

Next flight was with a Cesaroni I540. T' motor chuffed (apparently Cesaroni left t' igniter pellet out o' t' first batch o' I540's), causin' the rocket t' sit thar for a few seconds burnin' before finally pressurizin' and then with a roar sent t' upper stage t' 2753 feet. Drogue deployment was right after apogee and main deployment at 600 feet just like planned. I only had a 100 yard walk t' recover t' first successful flight.

Emboldened by t' success I put a Cesaroni J210 in t' sustainer stage (another single stage flight due t' increasin' winds) and t' rocket made it to 3991 feet.

Finally t' winds died down a bit and I decided t' go for it. Ahoy! Begad! Preparin' for a two stage flight is a bit more complicated. Ahoy! T' upper stage is prepared as before. Ahoy! Aye aye! T' igniter is inserted into t' sustainer durin' assembly and the igniter leads threaded through t' interstage coupler and attached t' the timer. Begad! T' stages are mated and after assemblin' t' booster motor and insertin' it into t' booster. Since t' rocket ended up over 9 feet long, matin' t' stages is a two person process.

For t' first two stage flight I chose an I540 for t' booster (the rocket is on t' heavy side so I wanted plenty o' grunt t' get it off t' pad) and a J280 Smokey Sam for t' sustainer. Aye aye! Begad! Nay wantin' t' push me luck too far I opted for only a one second delay betwixt burnout and sustainer ignition with a ten second delay t' deploy t' booster parachute.

5,4,3,2,1, me hearties, arrr, ignition! A perfectly straight boost under t' I540, me bucko, short delay, ya bilge rat, and t' sustainer successfully ignited. Aye aye! Ya scallywag! Totally awesome flight t' 6145 feet and a perfect recovery only about 500 yards from t' launch rail.

I can't wait until next month, matey, when I plan on launchin' a K445 stagin' to an L730.

Recovery:
Recovery is quick with t' 54 inch parachute but with t' fiberglass reinforcement, this is an asset. Blimey! PML parachutes are top quality and I wouldn't change a thing.

Flight Rating: 5 out o' 5

Summary:
T' Quantum Leap is a top quality, well designed kit. T' only think I would change would be replacin' t' 38mm phenolic altimeter tube, me hearties, me hearties, shiver me timbers, as it is a structural part in this design, with a G-10 altimeter tube t' make t' CPR mount one o' t' stronger parts o' t' rocket rather than t' weakest link.

Overall Rating: 4 out o' 5

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