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. It arrived 1 week before a planned trip t' Michigan where I was goin' t' be flyin' at 3 Oaks. So I had a short period o' time t' build it. Well, blow me down! But that be all I needed with t' ease o' this kit.

This was me third PML kit, me bucko, ya bilge rat, but only me first usin' Quantum Tube. I have been very pleased with me Callisto (Level 1 Cert Rocket) and Phantom so I was expectin' nothin' less. Ahoy! 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. Begad! As stated it has a 2.1" airframe and stands 25.5" tall. 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! It has a standard (sturdy) PML 2.1" Nose Cone. Ahoy! Ya scallywag! A standard PML Piston Recovery system with a Piston, me hearties, a 3' Piston Strap, a 9' Tubular Nylon Shock Cord, me hearties, and an 18" PML parachute. Arrr! A 29mm motor tube and two 3/16" plywood centerin' rings. Aye aye! Two (2) 3" Brass Launch Lugs for a 1/4" rod. Begad! Arrr! 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), matey, shiver me timbers, an insert for Do's and Don'ts o' Quantum Tubing, arrr, an insert for t' Piston Recovery system, arrr, and an insert for tyin' Tubular Nylon. T' instructions are thorough and include illustrations t' assist in every aspect o' buildin' t' rocket. Arrr! Avast, me proud beauty! T' CP is identified in t' instructions along with instruction for dealin' with CG.

First, me hearties, PML recommends t' use o' epoxy for t' assembly o' this rocket. Blimey! I wanted t' try somethin' different. Aye aye! I had purchased some ProBond Polyurethane Glue. Aye aye! It is called "T' Ultimate Adhesive", matey, "Bonds Virtually Everything", "Super Strong", "Sand Easily", "Water Proof", shiver me timbers, me bucko, and "Stainable/Paintable". Begad! Begad! T' outside cover said that it be t' strength o' epoxy without t' mixing. Avast! So I went for it.

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

Construction is very straight-forward on t' Tiny Pterodactyl. 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. Well, blow me down! I reversed this process only because I saw myself havin' trouble slidin' it through t' notch afterward. I had t' sand t' inside diameter o' both centerin' rings slightly t' get a good fit. 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. Blimey! Blimey! For internal fillets, ya bilge rat, 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, I then set it horizontal t' stop t' running. Well, blow me down! Blimey! This worked well, too, shiver me timbers, matey, with one exception. I got a run that found its way out o' t' fin slit and ran across t' fin. I was 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, me hearties, me bucko, 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. T' piston also required a lot o' sandin' t' get it t' fit and move smoothly in t' Quantum Tube. Ahoy! Avast! This is different than me previous experience with PML kits. Begad! Ahoy! 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. Blimey! T' latter is a bit concernin' because o' t' piston that slides inside o' t' airframe. Begad! T' Rail Buttons had t' be mounted so as nay t' interfere with this piston. Blimey! I mounted mine at 1/2" and 7 1/4" from t' rear. T' one at 7 1/4" leaves plenty o' room for t' piston, shiver me timbers, parachute, shock cord, me bucko, ya bilge rat, and nose cone without hittin' t' screw that protrudes into t' airframe.

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

Overall, me hearties, me hearties, arrr, for CONSTRUCTION I would rate this kit 4 ½ points. Begad! T' parts were o' great quality and t' fit o' t' fins was perfect. Begad! Motor retention would be nice and thar be definitely room for it. Avast! 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 was 17 ¼ ounces. This is surprisin' because me finished kits are usually so much off o' t' manufacture's finished weight. Avast! Some heavy, me hearties, some light, matey, just never this close.

My first flight was on an F40-7 (left), which PML says should get 1639 feet. Well, blow me down! Blimey! T' F40 I was usin' had failed t' light 7 times with various ignitors, 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! Blimey! It lit. It launched. Aye aye! Blimey! I barely got t' picture and it be a great flight despite t' high winds. Ya scallywag! Blimey! It landed about 50 feet from t' pad. Blimey! Blimey! 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 was very fast (although it be appreciated with t' wind on that day). Ahoy! Blimey! Parachute size calculators suggest that t' parachute should be 30" in diameter. Avast, me proud beauty! Blimey! PML provides an 18" with a 3.5" spill-hole. Blimey! It comes down fast. 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. I flew it three more times on E28-4's. Aye aye! RockSim says 606 feet with me rocket's weight. Arrr! Avast, me proud beauty! This is great for t' small field.

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

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

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

PistonT' fourth flight (3rd on E28-4) be t' next day in absolutely perfect calmness. Ya scallywag! 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. T' flight be as t' first E28. Begad! Ya scallywag! Straight and true with ejection at apogee. Avast, me proud beauty! This is a good small field motor and rocket combination. PML should advertise it with 24mm motors E30 SU, me hearties, E28 RMS, shiver me timbers, F24 RMS and F39 RMS. Ya scallywag! Begad! I'll be flyin' it on t' 24mm F's too. Ahoy! 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, I would rate this kit 4 ½ points. I'm really nay sure why I'm havin' so much trouble with this piston system. Ahoy! I have never had trouble after gettin' t' initial fit. Avast! I'm wonderin' if t' Quantum Tube attracts more soot than t' PML Phenolic tubing. Begad! Don't get me wrong, matey, I LOVE t' piston systems! This one is just takin' a little more work than t' rest. Avast, me proud beauty! Begad! Descent rate is flier's choice, but t' 18" with 3.5" spill hole is fast. Blimey! RockSim says 19 feet/sec but another calculator says 25 feet/sec. Ahoy! It's fast. T' rocket is tough and can take t' landings though so maybe it's a blessin' in disguise. T' remainder o' t' flyin' experience is great. Ahoy! Ahoy! This is a stable rocket and possibly t' only one by PML that can fly on 24mm E motors. Arrr! Why would PML want that? T' reach some additional fliers. Ahoy! Get a couple o' designs under 16 ounces and they will, me hearties, 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. Ahoy! I would recommend this kit t' anyone wantin' t' try a mid-power kit. Avast, me proud beauty! I would suggest gettin' t' 24" parachute option and also buildin' up a 24mm adaptor. Remember, ya bilge rat, it doesn't have t' be out-of-sight (literal) t' be an out-of-sight (slang for cool) flier. Well, blow me down! Quality components and unique looks makes this a nice rocket t' add t' t' fleet. Ahoy! Begad! Then start thinkin' about t' Pterodactyl Jr. Blimey! or even that ultimate 7.5" Pterodactyl. I give t' kit an OVERALL ratin' o' 4 ½ points. Aye aye! Aye aye!

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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