Tintinique

Tintinique

OK, so it's nay exactly t' right proportions for Tin Tin's rocket, matey, ya bilge rat, matey, far too squat and stubby, matey, but that's why it's called Tintinique. Ahoy! Just As diamonique isn't diamond, Tintinique isn't Tin Tin. ( Anyone who doesn't know what I'm talkin' about here, matey, 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 was somethin' very different. Ahoy! It looked like a 50's retro rocket. Aye aye! It be great. Avast, me proud beauty! How on earth did they make t' body for that? It turns out, 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, arrr, me hearties, and dig it up in t' future. Avast, me proud beauty! Blimey! Bein' Nestlé o' course they sold it full o' sweets (candy for those o' you across t' pond). Ya scallywag! Blimey! Begad! Blimey! For some bizzarre reason known only t' t' designer, matey, matey, t' capsule itself, matey, was made from a shape resemblin' t' body o' a typical sci-fi or cartoon rocket. Ya scallywag! Blimey! Better still, t' screw-on lid be easily convertible into a removeable nose cone. Whoever it was I'd love t' ask them why they did it. I buy two, one for a podded Tin Tin rocket, t' other for spare.

Anyway, matey, time passes and every time I go t' a launch thar's another time capsule. Avast! I've got t' build this thing. Ya scallywag! Blimey! I decide t' build it for RMR DesCon6. Blimey! Time passes. Blimey! Ahoy! DesCon6 begins. Time passes. Ahoy! DesCon6 finishes. UKRA 2000 approaches, and I realise that t' rocket I intended t' take, Accusatory Finger o' Suspicion, isn't goin' t' be ready. I dig out t' time capsule. I dig out cover scans o' t' books Destination Moon, arrr, 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! Time capsules are cheaply moulded, ya bilge rat, shiver me timbers, thick in some places thin in others, ya bilge rat, and very flexible. Avast, me proud beauty! Begad! I had decided that it be t' have a 29mm motor mount t' utilise t' short 29mm casings I had, and so t' body would need t' be reinforced. It needs an internal body tube, shiver me timbers, t' give structural strength and provide somethin' t' attach other components to, leavin' t' time capsule t' form only an outer shell. I had some 3" plastic tubin' that I had got from Ziggy at K-Lob, and this seemed ideal. Begad! Begad! I could have used standard 3" PML phenolic, arrr, shiver me timbers, or even quantum tubing, arrr, 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, and hacked a 3" diameter hole in t' base. Aye aye! T' openin' at t' top o' t' time casule was larger than 3", shiver me timbers, shiver me timbers, so I cut a 3mm thick plywood centerin' ring, and glued it in place, me bucko, matey, under t' shoulder. 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, so I draw some rough sketches, me hearties, me bucko, then some rough, dimensioned sketches. Arrr! Ahoy! My son, James, arrr, draws some sketches. Well, blow me down! I'm nay really gettin' anywhere. Arrr! It's all free hand and nay very satisfactory. Aye aye! 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, and so I'm nay goin' t' trust what it says about stability, arrr, but at least it helps visualise what t' rocket will look like when complete.

Inner body tube, motor mount

Inner body tube, shiver me timbers, parachute bay

Aft centerin' ring, retainin' nuts

Aft centerin' ring, retainin' clips

Construction

Motor Mount & Retention

I do have a short piece o' PML 29mm motor mount. Begad! I had originally intended for t' motor mount t' run t' length o' t' body, 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, me bucko, arrr, and anyway I don't have enough motor mount for t' full length o' t' internal body tube. Ahoy! So, I decide t' have a short motor mount, matey, givin' t' full internal diameter o' t' internal tube for a parachute. Blimey! Begad! I cut two, 3mm thick, plywood centerin' rings that fit over t' motor mount and into t' plastic tube. T' forward centerin' rin' has a notch t' pass a nylon strap. Well, blow me down! Avast, arrr, me proud beauty! T' strap is about25mm wide and 400mm long. T' nylon strap will provide an attachment point for t' elastic shock cord. Ahoy! Begad! T' strap is t' epoxied t' t' inside o' t' internal body tube. 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! Begad! T' aft cebterin' rein' was fitted, ya bilge rat, with no epoxy, arrr, t' t' aft o' t' motor mount. Aye aye! Arrr! T' forward centerin' rin' was epoxied into t' internal motor mount. Well, blow me down! Once t' forward centerin' rin' be fixed, arrr, t' aft centerin' rin' was removed. Ya scallywag! This gives access t' t' inside o' t' internal body tube, shiver me timbers, for filleting.

As I'm plannin' on flyin' with a 29mm RMS, ya bilge rat, arrr, no thrust rin' is required. Ya scallywag! Blimey! But I do need a retention system. I decide on a Kaplow Klip style affair. Ahoy! Blimey! Blimey! Blimey! Two M5 nuts are glued t' t' forward side o' t' aft centerin' ring. Begad! Blimey! Then a hole is drilled in t' center o' t' nuts, me hearties, matey, through t' centerin' ring, ya bilge rat, takin' care t' use a small enough drill bit that t' threads aren't stripped. Ahoy! Blimey! Once dry, me hearties, bolts are screwed into t' nuts and through t' plywood o' t' centerin' ring. Aye aye! Blimey! T' clips are made from aluminium, me bucko, bent t' shape by hammerin' them over, while held in a vice. Aye aye! Blimey! 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, me bucko, arrr, when viewed side-on. Ya scallywag! This neccessitated a four fin design, ya bilge rat, which was fine. Ya scallywag! I reckoned I needed all t' stability I could get. Avast, me proud beauty! It wasn't consistant with Tin Tin, but what t' hey, artistic license! Given t' flimsiness o' t' outer shell, matey, t' fins have t' be through-the-wall. Blimey! In t' end I descide t' make them pass through t' wall o' t' inner body tube too. Avast! That way they can be securely mounted t' t' motor mount. Begad! This means that all t' major structural elements are glued t' each other, arrr, givin' maximum strength.

T' more I think about t' fins pods, t' more they seem like a nose cone, but rounded at t' base, arrr, where t' shoulder would normally be. Blimey! I've had custom nose cones made before. Ya scallywag! I sketch a plan and get them made by Rockets & Things. Begad! I order five, one for emergencies! They arrive within a few days, and I'm well pleased, exactly t' right shape, and all identical. 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. I leave a large tab for through-the-wall mounting. Well, blow me down! Blimey! I'm still wonderin' how t' mount t' pods. Well, blow me down! Shouls I try t' slot them and slip them over t' fin? Tricky. Begad! Cut t' fin t' t' shape o' t' pod and make a butt-joint? Trickier. Blimey! Ahoy! Eventually I take t' brute force method and saw t' pods in half along their vertical axis. Ahoy! T' thickness o' t' saw takes about 1.5mm from t' diameter, measure at right angles t' t' cut. A little sanding, shiver me timbers, required anyway t' level t' cut up a bit, arrr, removes 3mm in total. Arrr! Blimey! When placed on either side o' t' fin, matey, me hearties, they are back t' t' original diameter. Aye aye! T' pod halves are simply glued t' either side o' a fin with carpenters glue, ya bilge rat, clamped up and left t' dry.

Next step is t' seal t' balsa and plywood. Well, blow me down! I use several coats o' sandin' sealer, matey, me bucko, with a light sandin' o' 120 grit betwixt coats. Aye aye! Next I fill t' joins. Begad! Aye aye! I've tried all kinds o' filler. Well, ya bilge rat, blow me down! P38, specialist modelling filler, Ronseal exterior wood filler all sorts, matey, me hearties, and they all smell terrible! Blimey! I found t' P38 dries too smartly and sets too hard. Arrr! Ya scallywag! Blimey! T' modellin' filler is expensive and doesn't stick t' phenolic very well. Begad! Blimey! I like t' Ronseal best, me hearties, it be workable longer, and easier t' sand, ya bilge rat, but heavy. Well, blow me down! Blimey! I like t' fill t' spirals in phenolic tubin' with this. Avast! Ya scallywag! Blimey! In t' end I use t' specialist modelling filler because it's light. Begad! 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. Avast! Well, matey, blow me down! I apply a few light coats o' primer t' t' pods, sandin' betwixt coats.

Fin Assembly

To allow for through-the-wall mountin' o' t' fins, me bucko, ya bilge rat, I need t' cut fin slots in both t' inner body tube and t' outer body shell. I use a Dremmel for this with a disc cutter. Ya scallywag! T' slots in t' inner body tube are true closed slots for strength. Avast, me proud beauty! Ya scallywag! I reason that it will be easier t' attach t' fins t' t' inner body tube, shiver me timbers, before t' outer body shell is fitted. Well, blow me down! Well, blow me down! 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. Blimey! This reduces teh strength, me bucko, 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. Well, blow me down! Epoxy fillets are made where t' fins attach t' t' motor mount, and on both t' inside and outside o' t' inner body. Blimey! T' slots are longe enough t' stretch from t' forward centerin' rin' t' t' aft centerin' ring. This all adds strength, but weight as well. Avast! 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. Ahoy! I don't have any, ya bilge rat, so make a short tlength from t' same tubing. Ya scallywag! 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. Well, blow me down! Avast, me proud beauty! Is epoxy t' cut out strip t' t' back o' t' join for reinforcement. Begad! This tube is first superglued and then epoxied into t' nose cone.

Fully assembled

Fully assembled, aft view

Final Assembly

Just in time, matey, matey, matey, I realise that t' outer shell isn't goin' t' be strong enough t' attach a launch lug to, ya bilge rat, without some form o' reinforcement. Avast! I cut a small rectangulat slot in t' side o' t' body shell. Ahoy! Avast, me proud beauty! Blimey! I epoxy some plywood t' t' interior o' t' shell, behind t' slot. Ahoy! Avast, me hearties, me proud beauty! Blimey! 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. Aye aye! Avast! Actually t' inner tube is glued t' t' centerin' rin' previously fixed into t' outer shell. Blimey! Because t' aft and o' t' shell is flappin' about a bit, I tack it into place with CA. Arrr! Avast! Then I apply a liberal application o' epoxy, t' t' aft end and also t' t' fin roots. Arrr! Once it's all set, arrr, it gets sanded and filled. T' epoxy fillets in t' fin roots turn out a bit rough, so I rebuild t' fillets with Ronseal. Ya scallywag! Prime, sand, fill, sand, primne, sand, fill, sand, prime, ya bilge rat, sand. Or somethin' like that. Ya scallywag! Begad! It's ready. Begad! I rub it down lightly with 200 grit wet and dry.

Swin' test

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

Now, ya bilge rat, this be t' biggest rocket I've ever swung test, me bucko, and it turns out me garden isn't quite big enough, ya bilge rat, nay when t' washin' is dryin' anyway. Ya scallywag! So I comandeer t' next door neighbours garden, arrr, me hearties, because they're nay in. Begad! Begad! Needless t' say they came home durin' t' swin' test, me hearties, shiver me timbers, matey, but they're used t' it by now. Ahoy! Anyway I start t' swing, and it jumps into t' right orientation. Great. Aye aye! Blimey! I do a few more sims, matey, usin' different motors, and it doesn't go very high. Arrr! Ya scallywag! So I reduce t' nose weight t' about 100g, arrr, ya bilge rat, or t' be more exact 31p. Another quick swin' test and it's still good. 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. I drill a hole into t' nose weight, matey, arrr, fill it with epoxy, matey, ya bilge rat, and insert an eye hook. Sorted.

Primed

Primed, aft view

Painting

Finish

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

Flight Test

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

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

Nosecone damage