Tintinique

Tintinique

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

Nestlé time capsule

Centerin' rin' in position

Time Capsules

In October 99, me bucko, ya bilge rat, I attended K-Lob in Lincolnshire. Avast, shiver me timbers, me proud beauty! Amongst t' rockets thar was somethin' very different. Begad! Avast, me proud beauty! It looked like a 50's retro rocket. Avast! It was great. Begad! 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, ya bilge rat, arrr, 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, me bucko, was made from a shape resemblin' t' body o' a typical sci-fi or cartoon rocket. Better still, t' screw-on lid was easily convertible into a removeable nose cone. Begad! Whoever it be I'd love t' ask them why they did it. Begad! Avast! I buy two, me bucko, one for a podded Tin Tin rocket, t' other for spare.

Anyway, ya bilge rat, time passes and every time I go t' a launch thar's another time capsule. Aye aye! Avast, me proud beauty! I've got t' build this thing. Ya scallywag! Well, shiver me timbers, blow me down! I decide t' build it for RMR DesCon6. Ya scallywag! Time passes. Avast! DesCon6 begins. Avast! Time passes. Well, blow me down! DesCon6 finishes. Aye aye! UKRA 2000 approaches, ya bilge rat, and I realise that t' rocket I intended t' take, arrr, Accusatory Finger o' Suspicion, ya bilge rat, isn't goin' t' be ready. Well, blow me down! I dig out t' time capsule. Arrr! I dig out cover scans o' t' books Destination Moon, arrr, ya bilge rat, and Explorers on t' Moon. Begad! 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. Avast, arrr, me proud beauty! Time capsules are cheaply moulded, thick in some places thin in others, and very flexible. 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. Aye aye! 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, shiver me timbers, arrr, and this seemed ideal. I could have used standard 3" PML phenolic, 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, and hacked a 3" diameter hole in t' base. Avast, me proud beauty! Avast! T' openin' at t' top o' t' time casule was larger than 3", so I cut a 3mm thick plywood centerin' ring, matey, and glued it in place, under t' shoulder. T' plastic tube now fits snugly at both ends.

T' preliminary sketches

View full size

Design

I still don't know what t' completed rocket will look like, so I draw some rough sketches, ya bilge rat, then some rough, shiver me timbers, dimensioned sketches. My son, me bucko, James, draws some sketches. I'm nay really gettin' anywhere. Begad! It's all free hand and nay very satisfactory. Rocksim! T' time capsule is suprisingly easy t' describe usin' a parabolic nose cone, shiver me timbers, and a couple o' eliptical transitions. Now, shiver me timbers, Rocksim isn't really designed for this shape o' rocket, me bucko, 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, matey, me bucko, 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, shiver me timbers, 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, shiver me timbers, and anyway I don't have enough motor mount for t' full length o' t' internal body tube. Well, blow me down! So, shiver me timbers, I decide t' have a short motor mount, shiver me timbers, givin' t' full internal diameter o' t' internal tube for a parachute. I cut two, ya bilge rat, 3mm thick, plywood centerin' rings that fit over t' motor mount and into t' plastic tube. Avast! T' forward centerin' rin' has a notch t' pass a nylon strap. Begad! Blimey! T' strap is about25mm wide and 400mm long. Avast, me hearties, me proud beauty! T' nylon strap will provide an attachment point for t' elastic shock cord. Begad! T' strap is t' epoxied t' t' inside o' t' internal body tube. Avast, me proud beauty! 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. Ahoy! T' aft cebterin' rein' be fitted, arrr, with no epoxy, t' t' aft o' t' motor mount. Aye aye! T' forward centerin' rin' was epoxied into t' internal motor mount. Avast, me proud beauty! Once t' forward centerin' rin' be fixed, 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. Ya scallywag! But I do need a retention system. Arrr! I decide on a Kaplow Klip style affair. Begad! Avast, me proud beauty! Blimey! Two M5 nuts are glued t' t' forward side o' t' aft centerin' ring. Begad! Ahoy! Blimey! Then a hole is drilled in t' center o' t' nuts, me hearties, through t' centerin' ring, me bucko, arrr, matey, takin' care t' use a small enough drill bit that t' threads aren't stripped. Ahoy! Once dry, me bucko, bolts are screwed into t' nuts and through t' plywood o' t' centerin' ring. Arrr! Blimey! T' clips are made from aluminium, shiver me timbers, bent t' shape by hammerin' them over, matey, shiver me timbers, while held in a vice. 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, when viewed side-on. Avast! This neccessitated a four fin design, me hearties, shiver me timbers, which was fine. Begad! Well, matey, blow me down! I reckoned I needed all t' stability I could get. Blimey! Arrr! It wasn't consistant with Tin Tin, matey, but what t' hey, artistic license! Given t' flimsiness o' t' outer shell, matey, t' fins have t' be through-the-wall. Ahoy! Ya scallywag! In t' end I descide t' make them pass through t' wall o' t' inner body tube too. Avast, me proud beauty! That way they can be securely mounted t' t' motor mount. Aye aye! Avast, me proud beauty! This means that all t' major structural elements are glued t' each other, 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. I've had custom nose cones made before. Ahoy! I sketch a plan and get them made by Rockets & Things. I order five, one for emergencies! They arrive within a few days, matey, and I'm well pleased, arrr, exactly t' right shape, me hearties, and all identical. Begad! Aye aye! 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. Aye aye! I'm still wonderin' how t' mount t' pods. Begad! Shouls I try t' slot them and slip them over t' fin? Tricky. Ya scallywag! Cut t' fin t' t' shape o' t' pod and make a butt-joint? Trickier. Ahoy! Eventually I take t' brute force method and saw t' pods in half along their vertical axis. Avast, me proud beauty! T' thickness o' t' saw takes about 1.5mm from t' diameter, measure at right angles t' t' cut. Avast! Begad! A little sanding, required anyway t' level t' cut up a bit, arrr, removes 3mm in total. Well, blow me down! When placed on either side o' t' fin, they are back t' t' original diameter. Well, blow me down! Arrr! T' pod halves are simply glued t' either side o' a fin with carpenters glue, me bucko, clamped up and left t' dry.

Next step is t' seal t' balsa and plywood. Begad! Begad! I use several coats o' sandin' sealer, with a light sandin' o' 120 grit betwixt coats. Ahoy! Next I fill t' joins. I've tried all kinds o' filler. Begad! P38, me hearties, specialist modelling filler, me bucko, Ronseal exterior wood filler all sorts, me bucko, and they all smell terrible! I found t' P38 dries too smartly and sets too hard. Arrr! T' modellin' filler is expensive and doesn't stick t' phenolic very well. Aye aye! Ya scallywag! I like t' Ronseal best, it was workable longer, and easier t' sand, but heavy. Well, blow me down! I like t' fill t' spirals in phenolic tubin' with this. Ya scallywag! 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. Ya scallywag! Aye aye! 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, I need t' cut fin slots in both t' inner body tube and t' outer body shell. Arrr! I use a Dremmel for this with a disc cutter. Ahoy! 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, before t' outer body shell is fitted. If I do that I won't be able t' get t' outer body shell on, arrr, me hearties, so I make those slots all t' way t' t' bottom. This reduces teh strength, but t' body shell isn't really stuctural anyway. Ya scallywag! T' fins are slotted into place in t' inner body and epoxied t' t' motor mount. Epoxy fillets are made where t' fins attach t' t' motor mount, and on both t' inside and outside o' t' inner body. Begad! T' slots are longe enough t' stretch from t' forward centerin' rin' t' t' aft centerin' ring. Aye aye! This all adds strength, ya bilge rat, but weight as well. 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. Aye aye! Begad! I don't have any, arrr, 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. Ya scallywag! 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, ya bilge rat, aft view

Final Assembly

Just in time, matey, 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. I epoxy some plywood t' t' interior o' t' shell, arrr, behind t' slot. Aye aye! Ahoy! 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. Begad! 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. Ahoy! Then I apply a liberal application o' epoxy, arrr, t' t' aft end and also t' t' fin roots. Blimey! Once it's all set, it gets sanded and filled. Ahoy! T' epoxy fillets in t' fin roots turn out a bit rough, so I rebuild t' fillets with Ronseal. Blimey! Begad! Prime, me bucko, sand, fill, sand, ya bilge rat, me bucko, primne, shiver me timbers, sand, arrr, fill, sand, prime, sand. Avast, me bucko, me proud beauty! Or somethin' like that. Avast! Arrr! It's ready. Ya scallywag! 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. 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. Blimey! I still reckon I need nose weight, me hearties, but what t' use? Lead would be good, me hearties, 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, me hearties, arrr, Shaun has t' answer, doubloon o' t' realm. Arrr! Begad! One pees are quite heavy for their size. I add 200g o' weight t' t' nose. Ahoy! Well, blow me down! Rocksim says "marginal". Blimey! Blimey! Blimey! 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 hearties, me hearties, and it turns out me garden isn't quite big enough, me bucko, nay when t' washin' is dryin' anyway. So I comandeer t' next door neighbours garden, because they're nay in. Begad! Needless t' say they came home durin' t' swin' test, matey, me hearties, but they're used t' it by now. Avast, me proud beauty! Anyway I start t' swing, me bucko, and it jumps into t' right orientation. Blimey! Arrr! Great. Begad! I do a few more sims, usin' different motors, and it doesn't go very high. Begad! So I reduce t' nose weight t' about 100g, 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. Ahoy! Begad! Once t' epoxy is dry I realise that I have no where t' attach t' shock cord to. Begad! I drill a hole into t' nose weight, fill it with epoxy, and insert an eye hook. Arrr! Blimey! Sorted.

Primed

Primed, aft view

Painting

Finish

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

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

Nosecone damage