Tintinique

Tintinique

OK, arrr, ya bilge rat, so it's nay exactly t' right proportions for Tin Tin's rocket, far too squat and stubby, but that's why it's called Tintinique. Ya scallywag! Just As diamonique isn't diamond, me bucko, Tintinique isn't Tin Tin. Begad! ( Anyone who doesn't know what I'm talkin' about here, shiver me timbers, needs t' watch more QVC!)

Nestlé time capsule

Centerin' rin' in position

Time Capsules

In October 99, I attended K-Lob in Lincolnshire. Amongst t' rockets thar be somethin' very different. Ahoy! Ya scallywag! It looked like a 50's retro rocket. Arrr! Begad! It be great. Begad! How on earth did they make t' body for that? It turns out, shiver me timbers, ya bilge rat, that durin' t' run up t' t' millenium celebrations someone at Nestlé thought it would be a good idea t' produce a time capsule in which people could bury stuff, matey, and dig it up in t' future. Aye aye! Bein' Nestlé o' course they sold it full o' sweets (candy for those o' you across t' pond). Ahoy! Ya scallywag! For some bizzarre reason known only t' t' designer, t' capsule itself, was made from a shape resemblin' t' body o' a typical sci-fi or cartoon rocket. Begad! Better still, t' screw-on lid was easily convertible into a removeable nose cone. Ya scallywag! Whoever it be I'd love t' ask them why they did it. Begad! I buy two, one for a podded Tin Tin rocket, t' other for spare.

Anyway, shiver me timbers, time passes and every time I go t' a launch thar's another time capsule. Arrr! Aye aye! I've got t' build this thing. Well, blow me down! I decide t' build it for RMR DesCon6. Avast! Ya scallywag! Time passes. DesCon6 begins. Begad! Time passes. DesCon6 finishes. Begad! Begad! UKRA 2000 approaches, me bucko, and I realise that t' rocket I intended t' take, ya bilge rat, ya bilge rat, Accusatory Finger o' Suspicion, isn't goin' t' be ready. I dig out t' time capsule. Avast! I dig out cover scans o' t' books Destination Moon, shiver me timbers, and Explorers on t' Moon. I wonder how on earth I'm goin' t' make t' fin pods.

I ignore t' question o' t' fin pods, and start t' think about t' body instead. Ahoy! Blimey! Time capsules are cheaply moulded, matey, thick in some places thin in others, matey, and very flexible. I had decided that it was t' have a 29mm motor mount t' utilise t' short 29mm casings I had, and so t' body would need t' be reinforced. Ya scallywag! Blimey! It needs an internal body tube, t' give structural strength and provide somethin' t' attach other components to, ya bilge rat, leavin' t' time capsule t' form only an outer shell. Begad! Blimey! Begad! Blimey! I had some 3" plastic tubin' that I had got from Ziggy at K-Lob, me bucko, matey, and this seemed ideal. Ya scallywag! Blimey! Begad! Blimey! I could have used standard 3" PML phenolic, me bucko, or even quantum tubing, but I didn't have any.

In order t' fit t' internal body tube into t' time capsule I hacked off t' screw thread at t' open end, me hearties, and hacked a 3" diameter hole in t' base. Aye aye! T' openin' at t' top o' t' time casule be larger than 3", shiver me timbers, arrr, so I cut a 3mm thick plywood centerin' ring, me bucko, and glued it in place, me bucko, under t' shoulder. Begad! T' plastic tube now fits snugly at both ends.

T' preliminary sketches

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Design

I still don't know what t' completed rocket will look like, arrr, me hearties, so I draw some rough sketches, ya bilge rat, then some rough, me hearties, dimensioned sketches. Avast, me proud beauty! My son, me hearties, James, draws some sketches. Ya scallywag! I'm nay really gettin' anywhere. Avast! It's all free hand and nay very satisfactory. Arrr! Rocksim! T' time capsule is suprisingly easy t' describe usin' a parabolic nose cone, and a couple o' eliptical transitions. Now, Rocksim isn't really designed for this shape o' rocket, shiver me timbers, shiver me timbers, and so I'm nay goin' t' trust what it says about stability, but at least it helps visualise what t' rocket will look like when complete.

Inner body tube, motor mount

Inner body tube, me bucko, parachute bay

Aft centerin' ring, retainin' nuts

Aft centerin' ring, me bucko, me hearties, retainin' clips

Construction

Motor Mount & Retention

I do have a short piece o' PML 29mm motor mount. Avast! I had originally intended for t' motor mount t' run t' length o' t' body, me hearties, ya bilge rat, with t' space for a parachute betwixt t' internal body tube and t' motor mount. It doesn't look like enough room for a chute, ya bilge rat, and anyway I don't have enough motor mount for t' full length o' t' internal body tube. Avast, me proud beauty! So, I decide t' have a short motor mount, givin' t' full internal diameter o' t' internal tube for a parachute. Well, blow me down! I cut two, me bucko, 3mm thick, arrr, plywood centerin' rings that fit over t' motor mount and into t' plastic tube. Begad! T' forward centerin' rin' has a notch t' pass a nylon strap. Begad! T' strap is about25mm wide and 400mm long. Ya scallywag! T' nylon strap will provide an attachment point for t' elastic shock cord. Ya scallywag! T' strap is t' epoxied t' t' inside o' t' internal body tube. Arrr! Throughout construction I use 5 minute or two ton Devcon epoxy.

T' forward centerin' rin' was epoxied t' t' forward end o' t' motor mount and allowed t' cure. Begad! Ya scallywag! T' aft cebterin' rein' be fitted, with no epoxy, me hearties, t' t' aft o' t' motor mount. Begad! Avast, me proud beauty! T' forward centerin' rin' be epoxied into t' internal motor mount. Once t' forward centerin' rin' be fixed, arrr, t' aft centerin' rin' be removed. Blimey! This gives access t' t' inside o' t' internal body tube, for filleting.

As I'm plannin' on flyin' with a 29mm RMS, shiver me timbers, matey, no thrust rin' is required. Ahoy! But I do need a retention system. Begad! Ahoy! I decide on a Kaplow Klip style affair. Aye aye! Avast, me proud beauty! Two M5 nuts are glued t' t' forward side o' t' aft centerin' ring. Then a hole is drilled in t' center o' t' nuts, through t' centerin' ring, arrr, takin' care t' use a small enough drill bit that t' threads aren't stripped. Avast, me proud beauty! Once dry, arrr, me bucko, bolts are screwed into t' nuts and through t' plywood o' t' centerin' ring. T' clips are made from aluminium, bent t' shape by hammerin' them over, while held in a vice. Avast! Ya scallywag! T' unformed blanks were about 10mm wide and 35mm long.

Fins & Fin Pods

Fins & Fin Pods

After much sketching, I eventually determine that t' most aesthetically pleasin' fin pattern (to me anyhow) is such that t' fins oposite each other on t' body form a semicircle, ya bilge rat, when viewed side-on. Avast! Begad! This neccessitated a four fin design, ya bilge rat, which be fine. Blimey! I reckoned I needed all t' stability I could get. It wasn't consistant with Tin Tin, arrr, me hearties, but what t' hey, artistic license! Given t' flimsiness o' t' outer shell, ya bilge rat, t' fins have t' be through-the-wall. Avast! In t' end I descide t' make them pass through t' wall o' t' inner body tube too. Avast! Ahoy! That way they can be securely mounted t' t' motor mount. Aye aye! This means that all t' major structural elements are glued t' each other, me bucko, matey, givin' maximum strength.

T' more I think about t' fins pods, t' more they seem like a nose cone, but rounded at t' base, where t' shoulder would normally be. Avast! I've had custom nose cones made before. Aye aye! I sketch a plan and get them made by Rockets & Things. Aye aye! I order five, me hearties, one for emergencies! They arrive within a few days, arrr, arrr, and I'm well pleased, me bucko, exactly t' right shape, shiver me timbers, and all identical. Begad! But how am I goin' t' attach them?

Rear view o' fins

Close up o' fin mounting

Rear view o' fins

While I ponder this I cut out t' fins from 3mm plywood. Begad! Blimey! I leave a large tab for through-the-wall mounting. I'm still wonderin' how t' mount t' pods. Begad! Shouls I try t' slot them and slip them over t' fin? Tricky. Cut t' fin t' t' shape o' t' pod and make a butt-joint? Trickier. Arrr! Eventually I take t' brute force method and saw t' pods in half along their vertical axis. Blimey! T' thickness o' t' saw takes about 1.5mm from t' diameter, me bucko, measure at right angles t' t' cut. Arrr! A little sanding, required anyway t' level t' cut up a bit, arrr, removes 3mm in total. When placed on either side o' t' fin, they are back t' t' original diameter. Begad! Arrr! T' pod halves are simply glued t' either side o' a fin with carpenters glue, clamped up and left t' dry.

Next step is t' seal t' balsa and plywood. Ahoy! I use several coats o' sandin' sealer, with a light sandin' o' 120 grit betwixt coats. Next I fill t' joins. I've tried all kinds o' filler. P38, ya bilge rat, specialist modelling filler, Ronseal exterior wood filler all sorts, me hearties, and they all smell terrible! I found t' P38 dries too smartly and sets too hard. Avast! T' modellin' filler is expensive and doesn't stick t' phenolic very well. Aye aye! I like t' Ronseal best, it was workable longer, and easier t' sand, me bucko, but heavy. Aye aye! Blimey! I like t' fill t' spirals in phenolic tubin' with this. Begad! In t' end I use t' specialist modelling filler because it's light. Ahoy! I don't need any extra weight at t' that end o' t' rocket! It takes a lot o' filler around t' join betwixt t' fin pod halves and t' fin. I apply a few light coats o' primer t' t' pods, shiver me timbers, sandin' betwixt coats.

Fin Assembly

To allow for through-the-wall mountin' o' t' fins, I need t' cut fin slots in both t' inner body tube and t' outer body shell. Blimey! I use a Dremmel for this with a disc cutter. Avast, me proud beauty! T' slots in t' inner body tube are true closed slots for strength. Ahoy! I reason that it will be easier t' attach t' fins t' t' inner body tube, matey, before t' outer body shell is fitted. Ahoy! If I do that I won't be able t' get t' outer body shell on, so I make those slots all t' way t' t' bottom. Avast, me proud beauty! This reduces teh strength, arrr, but t' body shell isn't really stuctural anyway. Begad! T' fins are slotted into place in t' inner body and epoxied t' t' motor mount. Avast! Begad! Epoxy fillets are made where t' fins attach t' t' motor mount, me bucko, and on both t' inside and outside o' t' inner body. T' slots are longe enough t' stretch from t' forward centerin' rin' t' t' aft centerin' ring. Begad! This all adds strength, arrr, but weight as well. Aye aye! Finally t' aft centerin' rin' is epoxied into position.

Nose Cone

I need a coupler tube that will fit into t' plastic tubin' o' t' inner body. Begad! I don't have any, so make a short tlength from t' same tubing. Avast, me proud beauty! I simply cut out a slot o' t' correct width t' reduce t' outer circimference t' that o' t' inner circumference o' t' opriginal tube. Is epoxy t' cut out strip t' t' back o' t' join for reinforcement. Aye aye! This tube is first superglued and then epoxied into t' nose cone.

Fully assembled

Fully assembled, me hearties, aft view

Final Assembly

Just in time, I realise that t' outer shell isn't goin' t' be strong enough t' attach a launch lug to, matey, without some form o' reinforcement. Blimey! I cut a small rectangulat slot in t' side o' t' body shell. Ahoy! Well, ya bilge rat, blow me down! I epoxy some plywood t' t' interior o' t' shell, arrr, behind t' slot. Arrr! T' epoxy gunges through t' slot, and I use it t' fix t' launch lug in place.

T' body shell slips on easily, and is epoxied initially t' just t' forward end. Ahoy! Actually t' inner tube is glued t' t' centerin' rin' previously fixed into t' outer shell. Avast! Begad! Because t' aft and o' t' shell is flappin' about a bit, arrr, me bucko, I tack it into place with CA. Avast! Then I apply a liberal application o' epoxy, t' t' aft end and also t' t' fin roots. Well, blow me down! Once it's all set, it gets sanded and filled. Blimey! T' epoxy fillets in t' fin roots turn out a bit rough, matey, ya bilge rat, so I rebuild t' fillets with Ronseal. Prime, sand, ya bilge rat, fill, sand, shiver me timbers, primne, sand, me bucko, shiver me timbers, fill, sand, prime, matey, arrr, sand. Blimey! Or somethin' like that. Begad! Avast, me hearties, me proud beauty! It's ready. Avast! I rub it down lightly with 200 grit wet and dry.

Swin' test

Because o' t' odd shape, I didn't trust t' stability factor given by Rocksim. Ya scallywag! Blimey! In fact rocksim reckoned it wasn't stable by a mile. Aye aye! Blimey! But you don't always need more than a calibre o' stability on a stubby rocket anyway. Aye aye! Blimey! I still reckon I need nose weight, me bucko, but what t' use? Lead would be good, but where can I get it and how much is it goin' t' cost, I'll probably have t' buy it by t' yard! Blimey! My eldest son, me hearties, Shaun has t' answer, doubloon o' t' realm. Begad! Blimey! One pees are quite heavy for their size. Begad! Blimey! I add 200g o' weight t' t' nose. Begad! Blimey! Ya scallywag! Blimey! Rocksim says "marginal". Aye aye! Well, matey, blow me down! I decide that t' only way t' be certain is a swin' test.

Now, this be t' biggest rocket I've ever swung test, me bucko, and it turns out me garden isn't quite big enough, nay when t' washin' is dryin' anyway. Avast! So I comandeer t' next door neighbours garden, matey, because they're nay in. Ahoy! Needless t' say they came home durin' t' swin' test, but they're used t' it by now. Ya scallywag! Anyway I start t' swing, and it jumps into t' right orientation. Well, blow me down! Great. Begad! Avast, me proud beauty! I do a few more sims, usin' different motors, matey, arrr, and it doesn't go very high. So I reduce t' nose weight t' about 100g, me bucko, or t' be more exact 31p. Another quick swin' test and it's still good. Avast, me proud beauty! Avast, me proud beauty! I blue t' nose wight into t' nose with epoxy. Once t' epoxy is dry I realise that I have no where t' attach t' shock cord to. Ahoy! I drill a hole into t' nose weight, fill it with epoxy, ya bilge rat, and insert an eye hook. Blimey! Sorted.

Primed

Primed, aft view

Painting

Finish

I had been primin' as I went along, so as soon as t' fin fillets were complete, arrr, it only took another couple o' coats t' get a nice smooth finish. Blimey! T' primer used throughout is Halfords car paint, in t' aerosol cans. Begad! I also use Halfords for t' main colours. Rover Diamond White and Volkswagen Mars Red. Begad! Ya scallywag! Seems appropriate really. Arrr! Ahoy! First I spray t' whole rocket white. I do about 3 coats, shiver me timbers, lightly sandin' betwixt each. Ahoy! I had decided much earlier on that a full Tin Tin chequerboard was far too much work, matey, so I had scaled t' pattern down t' two bands, ya bilge rat, o' four quadrants. Blimey! First I masked off every thin' above t' fins, me bucko, and painted everythin' below red. Ya scallywag! Avast, me proud beauty! I also painted t' nose cone. Begad! T' red covered really well in only two light coats. Well, blow me down! Avast, me hearties, me proud beauty! Next I painted t' two red quadrants o' t' lower band. So far so good. Well, blow me down! T' red quadrants o' t' upper band were hardest, ya bilge rat, bacause it was hard t' get a t' maskin' tape into exactly t' right position t' make t' square corners o' red meet exactly. Arrr! T' maskin' was t' hardest part o' t' entire project. Avast! Begad! T' red paint crept underneath t' tape in certain areas, ya bilge rat, and in other areas t' tape lifted off some small areas o' white when removed. Blimey! But I managed t' touch those defects up, and I'm pretty pleased with t' final outcome. Begad! Begad! It's t' best finish o' all t' rockets I've made so far. Ahoy! It needs goin' over with 400 grit wet and dry and a coat o' lacquer applying, arrr, matey, but thar's no time. Ya scallywag! UKRA 2000 starts tomorrow!

Flight Test

I use about 150mm o' Nomex® sheath over t' nylon strap, matey, and a Nomex® sheet above that t' protect t' chute. About 70mm o' 20mm elastic attach t' nose cone t' t' nylon strap. Aye aye! Blimey! A 34" PML chute is atached t' t' elastic too. Aye aye! I decide upon a G104 blue thunder reload. It's only just a G, but it gets t' rocket movin' quick. Avast! I reckon t' sooner I can get it up t' stable speed t' better.

It rains on Friday and Saturday, and I'm hesitant t' fly. Ahoy! Sunday is better, shiver me timbers, and I decide t' fly before I take up spottin' duty. Ahoy! Ya scallywag! On t' Staryrday I'd had it on a rod, matey, and found it was a little tight, but I had found a slightly smaller diametr rod, matey, me bucko, which be perfect. Avast, me proud beauty! Begad! I was pretty nervous durin' t' countdown, me hearties, and we had a hold for a low flyin' aircraft, but finally, t' moment comes. Aye aye! Well, blow me down! 5, me hearties, 4, ya bilge rat, 3, arrr, 2, 1 ignition. Avast! It's away! Great flight! It arced a bit after it left t' rod, but very smooth, ya bilge rat, no sign o' a wobble or instability o' any kind. Blimey! T' ejection fired right at apogee, matey, and Tintinique drifted slowly down, landin' approximately 40" from t' pad. Begad! There is a little damage t' t' nose cone,I can't figure out if it happened in flight or on impact with t' ground, me bucko, arrr, but I couldn't find t' piece chipped out so it probably happened in t' air. Easy t' fix, next flight comin' soon...

Nosecone damage