Das Modell Jumbo 3

Das Modell - Jumbo 3 {Kit}

Contributed by colin rowe

Manufacturer: Das Modell
Rating 1 out of 5
(Contributed - by Colin Rowe - 04/22/03)

Rocket PicBrief:
A single stage cluster rocket consistin' o' 4 x 24mm motor mounts. Transition from 80mm t' 60mm. Arrr! Ahoy! Splits at Centre. Ahoy! Avast, me proud beauty!

Construction:
T' Kit includes:

  • Instruction Sheet (in German nay translated)
  • 1-80mm tube.
  • 2-60mm tubes.
  • 1-60mm tube with fibreglass nosecone attached.
  • 3-plywood fins
  • 4-motor mounts (1.05" dia)
  • Centerin' rings (card)
  • Motor hooks
  • Waddin' (cotton wool????)
  • Elastic shock cord
  • A brass keyrin' (to attach chute)
  • Launch lugs
  • Several pieces o' balsa
  • Various stickers

T' instructions were in German, arrr, so I went on t' net t' translate them, this gave me some idea where most o' t' pieces went. Blimey! But as I translated more, it became clear that t' instructions were very general in nature and printed to be included in most o' t' kits!

A quick look over t' parts be all I needed t' see that most were o' poor quality and o' a bad finish. Blimey! T' balsa had been "snapped" t' length, the alumimium launch lugs (3/8") had been sawn by hand at a strange angle and t' burrs left on. Begad! T' grain on t' fins o' t' rocket were all at different angles, makin' 2 fins stiff and t' third able t' flex quite a lot. T' fibreglass nosecone has a very bad mismatch that had t' be t' be sanded out leavin' it very very thin in some places. T' body tubes were very thin and had deep spiral grooves in them. Ahoy! Blimey! T' motor mounts were brown card o' very poor quality and much too big in diameter for 24mm motors ( I have since found out that they fit t' German D7 motors that are larger)

On startin' t' build t' rocket, I wanted t' use 4 x 24mm Rowes Retainers coned retainers t' give a cool finish t' t' end o' t' rocket. Begad! Begad! But t' motor mount tubessupplied with t' kit were too big and t' quality was poor and would nay fit in t' centerin' rings suplied without kinking. Aye aye! I made some new centerin' rings from Tufnol and used motor mount tubesfrom Apollo with the tubes canted at an angle t' meet at t' rockets CP.

With t' motors now sorted, ya bilge rat, I moved on t' t' 80mm tube. Ahoy! This tube has t' be handled with care as it peels, ya bilge rat, creases or bends with t' slightest touch. The front o' t' tube has 2 rings glued into it t' reduce t' 80mm t' 60mm so the front tubes can fit into it. Aye aye! With t' rings glued in, me bucko, I tried t' fit t' card transition, shiver me timbers, me bucko, hard as I tried I could nay get it t' look anythin' like neat. Ya scallywag! Blimey! In the end I made one out o' foam and used that instead.

I wanted t' put an electronics bay in, but t' tube bein' "none standard size" I had t' cut up one o' t' tubes and a coupler t' make it. T' tube was very hard t' work with as it kept peeling, In t' end I managed it.

T' rest o' t' rocket be a little easier t' do. Well, blow me down! Well, blow me down! With t' fins on I looked for places t' put t' triangular balsa that was left, I could only assume that they went at t' base o' t' fins t' create a fillet o' sorts and add some support t' t' fins. With all this done, t' launch lugs were filed square and de-burred and fixed t' t' body, arrr, t' top lug havin' t' be stood off t' body. I felt they were a little weak so I glassed them on locally. Arrr! T' fit o' t' tubes were poor and t' couplers were a little too short makin' t' rocket have a crooked look t' it.

T' recovery was a big problem also. T' chute (if you could call it that" be a sheet o' silver plastic with a big blue circle marked on it. Begad! I cut this out and try as I might, I could nay get t' lines t' fix t' it without rippin' it in some way! So that went in t' bin along with t' elastic shock cord and t' other various fittings, and in went an Aerocon Chute and some Keelhaul®©™® line and swivels.

Finishing:
T' tube is a pig t' finish!!!!!!!

T' first sight o' paint and it all fluffs up. Let it dry and rub it down. Keep this up for about 5 coats then fill t' grooves. Well, blow me down! Be prepared for a long haul as it takes an age t' rub down. Arrr! Alittle t' hard and t' card tube just fluffs up again or bends and creases.

When you have primed, me hearties, filled again and again for several days you start to wonder what you are doin' this for!!!!.

In t' end if you have t' time, you can get a average finish on t' kit, but nothin' special.

Construction Rating: 1 out o' 5

Back EndFlight:
T' motors recomended are D7-3 but these are German motors and nay available in the UK so D12-5's were used.

T' motors were loaded into t' mounts and secured by Rowes Retainers 24mm cones. Begad! T' finished effect was just what I be lookin' for.

Waddin' be placed in t' rocket just above t' ejection charge o' t' MAD( Magnetic Apogee Detector). Aye aye! As this was t' first time I has used it I also had motor backup from t' D12's.

I made a set o' igniters usin' t' magnalite system and prepped ready to go.

T' rocket looked good on t' pad and I waited t' launch.

5 4 3 2 1 LAUNCH................

All 4 motors lit and t' rocket flew straight and true, ya bilge rat, slow and majestic, you could see all 4 motors burning. Well, blow me down! At apogee t' motors ejected and t' chute came out fine, t' decent rate looked fine too.

On recoverin' t' rocket quite a few things were wrong:

  • T' fins had split and come away from t' body just ripped t' tube.
  • T' tube above t' motors had scorched with t' ejection causin' t' paint to blister
  • t' upper part o' t' rocket havd kinked.
  • T' MAD did nay fire (my fault!)

T' damage was caused by t' tube bein' much too thin, me bucko, so t' fins just pulled it apart on landing. Blimey! Blimey! T' same for t' scorching, matey, shiver me timbers, if it be thicker there would nay be a problem.

Recovery:
Recovery was at a slow t' medium rate and should nay have caused any damage. Well, blow me down! If a larger chute was used then t' rocket would drift much too far. Avast, me proud beauty! T' problem is with t' strength o' t' kit. Avast!

Flight Rating: 1 out o' 5

Summary:
T' rocket looks impresive when done.

  • T' cons are:
  • T' kit is just too poor a quality t' be an asset t' your collection.
  • T' price is way too much for what you get. Well, shiver me timbers, blow me down! If I had known this before I started, I could have got all t' parts and built it myself for about t' same price with much better parts and built a much better rocket.

Binned parts:

  • All motor parts, centerin' rings, shiver me timbers, all recovery parts, decals, reducing templates

Parts made or bought:

  • Chute, me hearties, centerin' rings, recovery parts. Well, blow me down! Motor tubes. Blimey! Arrr! tranition cone, retainers.

Overall Rating: 1 out o' 5

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