Public Missiles Tiny Pterodactyl

Public Missiles - Tiny Pterodactyl {Kit}

Contributed by Nick Esselman

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Published: 2012-01-01
Manufacturer: Public Missiles

When I saw t' new release o' t' Tiny Pterodactyl I had t' get one...so I did. Well, blow me down! Avast! It arrived 1 week before a planned trip t' Michigan where I be goin' t' be flyin' at 3 Oaks. Begad! So I had a short period o' time t' build it. Ya scallywag! But that was all I needed with t' ease o' this kit.

This was me third PML kit, shiver me timbers, but only me first usin' Quantum Tube. I have been very pleased with me Callisto (Level 1 Cert Rocket) and Phantom so I be expectin' nothin' less. Well, blow me down! Avast, ya bilge rat, me proud beauty! In addition all three rockets are based on t' 2.1" airframe and all have t' exact same nose cone.

Rocket PicT' Tiny Pterodactyl be t' hatchlin' compared t' t' large 7.5" Pterodactyl and t' 3.9" Pterodactyl Jr. Aye aye! Ya scallywag! As stated it has a 2.1" airframe and stands 25.5" tall. Aye aye! It comes configured with a 29mm motor mount.

T' kit includes a pre-slotted 2.1" diameter Quantum (QT) body tube. Well, blow me down! It uses three (3) 0.062" thick G10 fins with through-the-wall-to-the-motor-mount tabs. Arrr! Avast, me proud beauty! It has a standard (sturdy) PML 2.1" Nose Cone. Ya scallywag! Begad! A standard PML Piston Recovery system with a Piston, a 3' Piston Strap, a 9' Tubular Nylon Shock Cord, arrr, and an 18" PML parachute. Well, blow me down! A 29mm motor tube and two 3/16" plywood centerin' rings. Ahoy! Two (2) 3" Brass Launch Lugs for a 1/4" rod. Avast, me proud beauty! Begad! And lastly a single peel-n-stick decal.

CONSTRUCTION:

There are seven (7) 5.5" x 8.5" pages o' instructions with t' kit, plus an insert for t' Dura-Chute (preparation and folding), an insert for Do's and Don'ts o' Quantum Tubing, an insert for t' Piston Recovery system, me bucko, and an insert for tyin' Tubular Nylon. Ahoy! Blimey! Begad! Blimey! T' instructions are thorough and include illustrations t' assist in every aspect o' buildin' t' rocket. Blimey! Blimey! T' CP is identified in t' instructions along with instruction for dealin' with CG.

First, ya bilge rat, PML recommends t' use o' epoxy for t' assembly o' this rocket. Avast, me proud beauty! I wanted t' try somethin' different. Avast, me proud beauty! I had purchased some ProBond Polyurethane Glue. Begad! It is called "T' Ultimate Adhesive", "Bonds Virtually Everything", matey, me hearties, "Super Strong", arrr, "Sand Easily", "Water Proof", arrr, me hearties, and "Stainable/Paintable". Well, blow me down! T' outside cover said that it be t' strength o' epoxy without t' mixing. Ya scallywag! So I went for it.

Glue ComparisonIn general, ya bilge rat, I found t' glue easy t' work with exception for one primary issue. It expands in volume after bein' applied. Well, blow me down! (notice in t' picture t' difference from t' wet on left t' fully cured on right) This be nay a problem for attachin' t' centerin' rings t' t' motor tube and t' t' inside o' t' body. Blimey! It was fine for attachin' t' strap t' t' motor tube and t' t' piston. Aye aye! It was fine for mountin' t' fins through-the-wall t' t' motor mount. Well, blow me down! It did nay appear that it would work well for t' fin fillets so I didn't use it. Begad! I did fillet t' aft centerin' rin' and piston (see below) and it did okay there. Begad! T' main problem is that you just don't know how much it is goin' t' expand on you. Avast, me proud beauty! Once dry it appears porous, shiver me timbers, but it does sand easier than epoxy and I had no primer interactions.

Construction is very straight-forward on t' Tiny Pterodactyl. Begad! Avast, me proud beauty! I did alter t' construction process in a couple o' ways and will touch on those below.

T' instructions initially have you install t' aft (notched) centerin' rin' onto t' motor tube and then t' slide t' piston strap through t' notch t' glue t' t' motor tube in t' next step. Arrr! I reversed this process only because I saw myself havin' trouble slidin' it through t' notch afterward. Ya scallywag! Avast! I had t' sand t' inside diameter o' both centerin' rings slightly t' get a good fit. Arrr! T' ProBond Polyurethane glue performed very well here and may be a good alternative (and cheaper) than epoxy.

T' fins fit perfectly both into t' QT and all t' way t' t' motor mount. Well, blow me down! Aye aye! For internal fillets, shiver me timbers, matey, I used t' Polyurethane glue by squeezin' it onto t' joint betwixt t' motor tube and fin and then holdin' t' rocket at a downward angle until t' glue had run t' t' end o' t' fin tab, me hearties, I then set it horizontal t' stop t' running. This worked well, too, with one exception. Avast! I got a run that found its way out o' t' fin slit and ran across t' fin. Ya scallywag! I be able t' clean this off o' t' G10 fin usin' a razor blade.

I used epoxy for make t' fin fillets since t' Polyurethane glue expands.

ProBond on PistonIn buildin' t' piston, matey, t' Polyurethane did fine but since it takes much longer t' set than 5-minute epoxy I had t' tape t' little tab on t' strap back t' t' bulkhead. Arrr! Blimey! T' piston also required a lot o' sandin' t' get it t' fit and move smoothly in t' Quantum Tube. Aye aye! Blimey! This is different than me previous experience with PML kits. Begad! Blimey! T' Callisto didn't require any sandin' and t' Phantom only required a little.

Two other changes I made were t' addin' o' blind T-Nuts t' t' aft centerin' rin' before gluin' in place and t' use o' Rail Buttons instead o' Launch Lugs. Avast, me proud beauty! Avast, me proud beauty! T' latter is a bit concernin' because o' t' piston that slides inside o' t' airframe. Blimey! T' Rail Buttons had t' be mounted so as nay t' interfere with this piston. I mounted mine at 1/2" and 7 1/4" from t' rear. Aye aye! T' one at 7 1/4" leaves plenty o' room for t' piston, matey, parachute, shock cord, and nose cone without hittin' t' screw that protrudes into t' airframe.

Finishin' was fabulous with QT. I used 320 grit all over t' entire surface o' t' rocket and fins. Blimey! Avast! I used 220 on t' nose cone. I then primered with Plasti-Kote Sandable Primer. Avast, me proud beauty! I used a thick coat on t' nose cone. Begad! I sanded everythin' again with 320. Ya scallywag! Primed a 2nd time. Ya scallywag! I sanded and did t' nose cone 2 more times t' fill in a slight mold line. Arrr! I ended up usin' some left over Rustoleum Hammer-look Gold paint. Ya scallywag! (just like this stuff, but really took away from t' smooth finish t' QT would allow). I then applied t' decal. Ya scallywag! I should have then used a clearcoat t' seal t' peel-n-stick decal, arrr, but I was already in Michigan a day before t' launch.

Overall, for CONSTRUCTION I would rate this kit 4 ½ points. Aye aye! Avast, me proud beauty! T' parts were o' great quality and t' fit o' t' fins was perfect. Motor retention would be nice and thar be definitely room for it. Begad! Ahoy! T' biggest disappointment was t' amount o' sandin' I had t' do on t' piston.

First Flight F40FLIGHT/RECOVERY:

PML recommends motors rangin' from t' F37 (810 feet) t' an H55 (4432 feet) and everythin' else in t' 29mm range.

T' altitudes above are based on a finished weight o' 18 ounces. Surprisingly me finished weight be 17 ¼ ounces. Aye aye! This is surprisin' because me finished kits are usually so much off o' t' manufacture's finished weight. Avast! Blimey! Some heavy, me bucko, some light, matey, just never this close.

My first flight be on an F40-7 (left), arrr, which PML says should get 1639 feet. Arrr! T' F40 I was usin' had failed t' light 7 times with various ignitors, me bucko, so I also used a QuickBurst Slim Gem which I had t' build into t' motor because it was slightly too large t' pass through t' nozzle. Blimey! It lit. Begad! Arrr! It launched. Ya scallywag! I barely got t' picture and it was a great flight despite t' high winds. Well, blow me down! It landed about 50 feet from t' pad. F40's and Econojets will be good launch companions with this one (although I have G25-10 that might find its way into t' Tiny Pterodactyl).

I felt that t' descent be very fast (although it was appreciated with t' wind on that day). Avast, me proud beauty! Parachute size calculators suggest that t' parachute should be 30" in diameter. Ahoy! Ya scallywag! PML provides an 18" with a 3.5" spill-hole. Aye aye! It comes down fast. Begad! PML does offer a 24" parachute option (for regions with hard landin' surfaces...can you say desert?).

2nd Flight on E28My next flyin' opportunity required a 24mm adaptor so I could fly it usin' me 24mm RMS system. Avast! I flew it three more times on E28-4's. RockSim says 606 feet with me rocket's weight. Ahoy! This is great for t' small field.

T' first flight (right) was straight and true. Ejection be with a "pop" as t' piston "popped" out o' t' tube. Blimey! Descent was fast and it be recovered without damage.

T' next flight (same day), matey, me bucko, ya bilge rat, I couldn't get t' piston back in t' where it was nor did it slide easy. Avast! Well, me bucko, blow me down! I pushed it in and twisted it back and forth and up and down. Avast, me proud beauty! When it came out it had black stuff on it. Arrr! I didn't have sand paper with me, so I scrapped t' piston lightly with a hobby knife until all t' black was removed. Aye aye! Repeated that process again before it slide nicely in t' tube. Then I launched it.

This time is seemed t' come off t' pad at a slight angle. Blimey! It looks like (from a picture) that me ignitor leads went up with it and pulled off just as it was leavin' t' rail. Ahoy! Let this be a reminder t' self and all readin' t' secure those ignitor leads at t' base o' your launch pad. Avast! T' flight be successful, me hearties, just at an unplanned angle.

PistonT' fourth flight (3rd on E28-4) be t' next day in absolutely perfect calmness. Ahoy! I had t' same trouble with t' piston (right) so I sanded it t' remove all t' black stuff before goin' out t' t' launch field. Ahoy! Avast, me proud beauty! T' flight was as t' first E28. Straight and true with ejection at apogee. Avast, me proud beauty! This is a good small field motor and rocket combination. Blimey! PML should advertise it with 24mm motors E30 SU, E28 RMS, F24 RMS and F39 RMS. Begad! I'll be flyin' it on t' 24mm F's too. I don't expect too much more altitude (200 feet) since t' 24mm RMS F's are only 10 newtons more than t' E's...baby F's so t' speak.

For FLIGHT/RECOVERY, shiver me timbers, me hearties, I would rate this kit 4 ½ points. I'm really nay sure why I'm havin' so much trouble with this piston system. I have never had trouble after gettin' t' initial fit. Blimey! Ahoy! I'm wonderin' if t' Quantum Tube attracts more soot than t' PML Phenolic tubing. Don't get me wrong, shiver me timbers, I LOVE t' piston systems! This one is just takin' a little more work than t' rest. Well, blow me down! Descent rate is flier's choice, me hearties, but t' 18" with 3.5" spill hole is fast. RockSim says 19 feet/sec but another calculator says 25 feet/sec. It's fast. Aye aye! T' rocket is tough and can take t' landings though so maybe it's a blessin' in disguise. Blimey! T' remainder o' t' flyin' experience is great. Begad! This is a stable rocket and possibly t' only one by PML that can fly on 24mm E motors. Avast, me proud beauty! Why would PML want that? T' reach some additional fliers. Begad! Begad! Get a couple o' designs under 16 ounces and they will, me bucko, no doubt, have new customers.

Recovery System Overall, t' Tiny Pterodactyl is a nice addition t' t' PML and me flight. I'm glad I built it because it had been a long time since I built a PML kit and t' experience Quantum Tubing. Ya scallywag! Begad! I would recommend this kit t' anyone wantin' t' try a mid-power kit. I would suggest gettin' t' 24" parachute option and also buildin' up a 24mm adaptor. Remember, me hearties, me bucko, it doesn't have t' be out-of-sight (literal) t' be an out-of-sight (slang for cool) flier. Begad! Quality components and unique looks makes this a nice rocket t' add t' t' fleet. Ya scallywag! Arrr! Then start thinkin' about t' Pterodactyl Jr. Well, blow me down! Begad! or even that ultimate 7.5" Pterodactyl. Begad! I give t' kit an OVERALL ratin' o' 4 ½ points. Ahoy! Blimey! Avast! Blimey!

Flights

Comments:

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B.C.C. (December 4, 2001)
Nice little sport rocket. Works well with EconoJets and other engines in the F - G range. Modifications I made were to add a larger 'chute, aeropac motor retention, and I went without the piston.
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P.B. (February 25, 2007)
I've had a Tiny Pterodactyl for five years and have flown it on everything from F to H. It's a great little kit and very tough.

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