Tintinique

Tintinique

OK, 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. Arrr! Just As diamonique isn't diamond, shiver me timbers, Tintinique isn't Tin Tin. Arrr! Avast, arrr, me proud beauty! ( Anyone who doesn't know what I'm talkin' about here, me hearties, ya bilge rat, me bucko, 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. It looked like a 50's retro rocket. Begad! It was great. How on earth did they make t' body for that? It turns out, arrr, 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, shiver me timbers, 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). For some bizzarre reason known only t' t' designer, t' capsule itself, arrr, was made from a shape resemblin' t' body o' a typical sci-fi or cartoon rocket. Aye aye! Better still, ya bilge rat, t' screw-on lid was easily convertible into a removeable nose cone. Avast! Whoever it was I'd love t' ask them why they did it. Blimey! Avast! 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. I've got t' build this thing. Aye aye! I decide t' build it for RMR DesCon6. Avast! Time passes. Ya scallywag! Ahoy! DesCon6 begins. Arrr! Time passes. Blimey! DesCon6 finishes. UKRA 2000 approaches, ya bilge rat, matey, shiver me timbers, and I realise that t' rocket I intended t' take, matey, Accusatory Finger o' Suspicion, me bucko, isn't goin' t' be ready. Ahoy! I dig out t' time capsule. Aye aye! I dig out cover scans o' t' books Destination Moon, and Explorers on t' Moon. Avast! I wonder how on earth I'm goin' t' make t' fin pods.

I ignore t' question o' t' fin pods, me bucko, and start t' think about t' body instead. Blimey! Blimey! Time capsules are cheaply moulded, thick in some places thin in others, matey, and very flexible. Arrr! Blimey! I had decided that it be t' have a 29mm motor mount t' utilise t' short 29mm casings I had, arrr, and so t' body would need t' be reinforced. It needs an internal body tube, t' give structural strength and provide somethin' t' attach other components to, leavin' t' time capsule t' form only an outer shell. Well, blow me down! I had some 3" plastic tubin' that I had got from Ziggy at K-Lob, me bucko, and this seemed ideal. Aye aye! Blimey! I could have used standard 3" PML phenolic, matey, or even quantum tubing, me bucko, 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, matey, and hacked a 3" diameter hole in t' base. Well, blow me down! Ya scallywag! T' openin' at t' top o' t' time casule be larger than 3", so I cut a 3mm thick plywood centerin' ring, and glued it in place, ya bilge rat, under t' shoulder. Aye aye! 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, then some rough, me bucko, dimensioned sketches. Ahoy! Begad! My son, me bucko, me bucko, James, draws some sketches. Ahoy! Begad! I'm nay really gettin' anywhere. It's all free hand and nay very satisfactory. Begad! Blimey! Rocksim! T' time capsule is suprisingly easy t' describe usin' a parabolic nose cone, and a couple o' eliptical transitions. Now, me hearties, me bucko, Rocksim isn't really designed for this shape o' rocket, and so I'm nay goin' t' trust what it says about stability, arrr, ya bilge rat, but at least it helps visualise what t' rocket will look like when complete.

Inner body tube, motor mount

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

As I'm plannin' on flyin' with a 29mm RMS, no thrust rin' is required. But I do need a retention system. Ahoy! Arrr! I decide on a Kaplow Klip style affair. Arrr! Arrr! Two M5 nuts are glued t' t' forward side o' t' aft centerin' ring. Avast, me proud beauty! Then a hole is drilled in t' center o' t' nuts, matey, through t' centerin' ring, takin' care t' use a small enough drill bit that t' threads aren't stripped. Once dry, bolts are screwed into t' nuts and through t' plywood o' t' centerin' ring. Avast! T' clips are made from aluminium, bent t' shape by hammerin' them over, while held in a vice. Ahoy! Well, blow me down! 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, when viewed side-on. This neccessitated a four fin design, which was fine. Aye aye! I reckoned I needed all t' stability I could get. Ya scallywag! It wasn't consistant with Tin Tin, shiver me timbers, but what t' hey, artistic license! Given t' flimsiness o' t' outer shell, t' fins have t' be through-the-wall. In t' end I descide t' make them pass through t' wall o' t' inner body tube too. Avast! Avast, me proud beauty! That way they can be securely mounted t' t' motor mount. Arrr! Avast, me proud beauty! 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, arrr, matey, t' more they seem like a nose cone, but rounded at t' base, arrr, where t' shoulder would normally be. Aye aye! Blimey! I've had custom nose cones made before. Ya scallywag! Aye aye! I sketch a plan and get them made by Rockets & Things. I order five, me bucko, one for emergencies! They arrive within a few days, arrr, ya bilge rat, and I'm well pleased, exactly t' right shape, arrr, me hearties, arrr, and all identical. Well, blow me down! Ahoy! 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. Arrr! I leave a large tab for through-the-wall mounting. Begad! Begad! I'm still wonderin' how t' mount t' pods. Avast, me proud beauty! Shouls I try t' slot them and slip them over t' fin? Tricky. Well, blow me down! Cut t' fin t' t' shape o' t' pod and make a butt-joint? Trickier. Begad! Eventually I take t' brute force method and saw t' pods in half along their vertical axis. T' thickness o' t' saw takes about 1.5mm from t' diameter, measure at right angles t' t' cut. Begad! Blimey! A little sanding, ya bilge rat, ya bilge rat, required anyway t' level t' cut up a bit, removes 3mm in total. Ahoy! When placed on either side o' t' fin, matey, they are back t' t' original diameter. Ahoy! 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. Avast, me bucko, me proud beauty! I use several coats o' sandin' sealer, with a light sandin' o' 120 grit betwixt coats. Begad! Next I fill t' joins. Blimey! Aye aye! I've tried all kinds o' filler. P38, specialist modelling filler, shiver me timbers, Ronseal exterior wood filler all sorts, and they all smell terrible! I found t' P38 dries too smartly and sets too hard. Well, blow me down! T' modellin' filler is expensive and doesn't stick t' phenolic very well. Well, shiver me timbers, blow me down! I like t' Ronseal best, ya bilge rat, matey, matey, it be workable longer, and easier t' sand, but heavy. Avast! Avast, me proud beauty! I like t' fill t' spirals in phenolic tubin' with this. Aye aye! Ahoy! In t' end I use t' specialist modelling filler because it's light. 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. Begad! I apply a few light coats o' primer t' t' pods, arrr, ya bilge rat, 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. Begad! Blimey! Begad! Blimey! I use a Dremmel for this with a disc cutter. Avast! Blimey! Avast! Blimey! T' slots in t' inner body tube are true closed slots for strength. I reason that it will be easier t' attach t' fins t' t' inner body tube, matey, me bucko, before t' outer body shell is fitted. Avast, me proud beauty! Blimey! If I do that I won't be able t' get t' outer body shell on, me hearties, so I make those slots all t' way t' t' bottom. Begad! Blimey! Well, blow me down! Blimey! This reduces teh strength, me hearties, arrr, but t' body shell isn't really stuctural anyway. Arrr! Blimey! Begad! Blimey! T' fins are slotted into place in t' inner body and epoxied t' t' motor mount. Well, blow me down! Blimey! Epoxy fillets are made where t' fins attach t' t' motor mount, and on both t' inside and outside o' t' inner body. Ahoy! Blimey! T' slots are longe enough t' stretch from t' forward centerin' rin' t' t' aft centerin' ring. Avast! Blimey! This all adds strength, but weight as well. Blimey! Blimey! Well, shiver me timbers, blow me down! Blimey! 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. Avast, me proud beauty! Blimey! I don't have any, so make a short tlength from t' same tubing. 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. 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, me bucko, I realise that t' outer shell isn't goin' t' be strong enough t' attach a launch lug to, without some form o' reinforcement. Arrr! I cut a small rectangulat slot in t' side o' t' body shell. Aye aye! I epoxy some plywood t' t' interior o' t' shell, behind t' slot. Avast, me proud beauty! T' epoxy gunges through t' slot, me bucko, arrr, 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. Actually t' inner tube is glued t' t' centerin' rin' previously fixed into t' outer shell. Because t' aft and o' t' shell is flappin' about a bit, I tack it into place with CA. Then I apply a liberal application o' epoxy, me bucko, t' t' aft end and also t' t' fin roots. Blimey! Once it's all set, me bucko, ya bilge rat, it gets sanded and filled. Avast! T' epoxy fillets in t' fin roots turn out a bit rough, me hearties, me hearties, so I rebuild t' fillets with Ronseal. Ahoy! Well, blow me down! Prime, sand, fill, matey, sand, primne, sand, fill, sand, prime, sand. Begad! Ya scallywag! Or somethin' like that. Ahoy! Ahoy! It's ready. I rub it down lightly with 200 grit wet and dry.

Swin' test

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

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

Primed

Primed, aft view

Painting

Finish

I had been primin' as I went along, shiver me timbers, arrr, so as soon as t' fin fillets were complete, ya bilge rat, it only took another couple o' coats t' get a nice smooth finish. T' primer used throughout is Halfords car paint, in t' aerosol cans. I also use Halfords for t' main colours. Ahoy! Rover Diamond White and Volkswagen Mars Red. Begad! Seems appropriate really. First I spray t' whole rocket white. Ahoy! I do about 3 coats, ya bilge rat, lightly sandin' betwixt each. I had decided much earlier on that a full Tin Tin chequerboard be far too much work, so I had scaled t' pattern down t' two bands, o' four quadrants. First I masked off every thin' above t' fins, and painted everythin' below red. Well, arrr, blow me down! I also painted t' nose cone. Avast! Begad! T' red covered really well in only two light coats. Next I painted t' two red quadrants o' t' lower band. Begad! 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' was t' hardest part o' t' entire project. Ahoy! T' red paint crept underneath t' tape in certain areas, arrr, arrr, me hearties, and in other areas t' tape lifted off some small areas o' white when removed. Avast! Blimey! But I managed t' touch those defects up, and I'm pretty pleased with t' final outcome. It's t' best finish o' all t' rockets I've made so far. Begad! It needs goin' over with 400 grit wet and dry and a coat o' lacquer applying, but thar's no time. Avast! 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. About 70mm o' 20mm elastic attach t' nose cone t' t' nylon strap. Ya scallywag! A 34" PML chute is atached t' t' elastic too. Begad! I decide upon a G104 blue thunder reload. Ahoy! Arrr! It's only just a G, but it gets t' rocket movin' quick. Blimey! Ahoy! I reckon t' sooner I can get it up t' stable speed t' better.

It rains on Friday and Saturday, me bucko, and I'm hesitant t' fly. Ahoy! Sunday is better, and I decide t' fly before I take up spottin' duty. Arrr! On t' Staryrday I'd had it on a rod, and found it was a little tight, me hearties, but I had found a slightly smaller diametr rod, me hearties, which was perfect. I was pretty nervous durin' t' countdown, arrr, and we had a hold for a low flyin' aircraft, ya bilge rat, but finally, me bucko, me hearties, matey, t' moment comes. Avast! Begad! 5, 4, 3, me bucko, ya bilge rat, 2, matey, me hearties, 1 ignition. It's away! Great flight! It arced a bit after it left t' rod, but very smooth, matey, 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. Aye aye! 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. Ya scallywag! Arrr! Easy t' fix, me bucko, next flight comin' soon...

Nosecone damage