Scratch Orion Original Design / Scratch Built

Scratch - Orion {Scratch}

Contributed by Bert Koerts

Manufacturer: Scratch
(by Bert Koerts - 12/20/02)

Note: This is a slightly condensed version o' all the information that Bert has produced for his Level 3 project. Arrr! Visit t' Tripoli Netherlands site (look under Projecten) t' read t' additional information and enjoy additional pictures.

Rocket PicIntroduction
In 1998 Wilfred van Bergen, who launched HPR rockets with t' NERO, an experimental rocketry group in t' Netherlands, introduced me t' HPR. Begad! Aye aye! I joined NERO and built a Binder Design Sentinel and launched it twice on J570's during the summer o' 1999.

T' number o' HPR-enthusiasts be steadily increasing, me bucko, so in December 1999 we founded Tripoli t' Netherlands. Avast, me proud beauty! Avast, me proud beauty! T' be able t' organize launches we needed at least two level 2, arrr, so off we went t' Tripoli Switzerland t' get our levels. In October 1999 I passed me Level 1, me hearties, in March 2000 me Level 2 - again with my Sentinel. In July 2000 Netherlaunch 1 - t' first launch o' Tripoli the Netherlands was organized.

In t' sprin' o' 2001 I hope t' attempt a Level 3 flight. Begad! In this project I hope t' implement all t' things I learned about buildin' rockets durin' the last 2 years.

Concept

  • I want t' implementin' techniques that are proven, shiver me timbers, preferably techniques that I have used before
  • I'd like t' design Orion t' maximize chance o' certification. Begad! A recovery system with redundancy built in, shiver me timbers, an anti-zipper airframe, me bucko, me hearties, fin-form designed to minimize chance o' damage.
  • T' rocket must be strong enough t' fly at least 5 times
  • Orion should fly on a 98-7680 (M1419) motor
  • Orion should be - or should be adapted t' have a static margin o' 1 t' 2, so I can launch it later in t' Netherlands - (NERO safety regulations)
  • Orion must fit into me car
  • If possible, Orion should be a very large rocket
  • Orion should be prepared for clustering; two canted 38 mm motor mounts will be installed and room for avionics and wires will be prepared. Arrr!
  • T' preppin' time o' Orion should be under 2,5 hours. Ya scallywag! Blimey! Blimey!

Nosecone

  • T' nosecone will be a glassed nosecone approx. Well, blow me down! 3.5:1 ogive
  • T' nosecone will be empty

Airframe

  • T' airframe will be 20 cm in diameter. (inner diameter: 20.0, shiver me timbers, shiver me timbers, outer 21.0)
  • Orion will have three sections and a nosecone: a fin section, an avionics section and a recovery section.

CarbonT' airframe will be built by gluin' a 2 mm thick sheet o' carbon fiber t' a phenolic tube. Begad! The carbon fiber will be laminated with laminatin' epoxy resin t' t' point that all carbon fiber is covered. Arrr! I used this technique in me Sentinel, it is heavy, but very durable. After 5 flights I have a few pits in t' epoxy (same as the repairable ones in t' windshield o' a car) but t' integrity o' t' tube is unaffected. My Sentinel had in t' first 3 flights no avionics and suffered some high-speed deployments (First launch at an angle o' 70 degrees, me bucko, me bucko, due to high winds) but never zippered.

T' components o' t' airframe (fin section, me bucko, me hearties, avionics bay and recovery bay will be bolted together by M10 bolts and nuts. Begad! T' couplers will be strengthened t' attach t' sections together.


Centering RingsFin Section
T' fins will consist o' a G10 and aeroplane grade plywood sandwich. Avast! T' G10 will be approx. Begad! 2 mm thick, t' plywood 0.8 cm. T' fins will be epoxied t' the motor mount, arrr, shiver me timbers, t' 4 centerin' rings and t' t' airframe. Blimey! Internally t' rigidity of t' motor mount / fin unit will be strengthened by epoxyin' rectangular plywood plates betwixt two fins and two centerin' rings.

T' centerin' rings will be made o' 6 mm high-density airplane grade plywood.


FinsFin SectionClose Up

Avionics
In Orion I'd like t' use two RDAS units. Aye aye! Begad! For me rockets I developed a standard size t' house avionics. Ya scallywag! This consists o' 25 cm 54 mm coupler tube, shiver me timbers, me bucko, large enough to house an RDAS, ya bilge rat, an expansion board and a 9 V battery. Arrr! These coupler tubes are fitted in a 54 mm PML Quantum tube and secured. Arrr! Begad! These Quantum tubes are built-in in t' avionics bay, one on each side. Arrr! Arrr! T' RDAS units can be armed through t' vent hole on t' outside o' t' airframe.

T' RDAS units fire 2 Daveyfire ignitors each, resultin' in t' ejection of the drogue and main chutes. This part o' Orion is tested in Sentinel and Yellow rockets.

Both RDAS units produce t' same beep when armed. Avast, me proud beauty! T' avoid problems with this, matey, ya bilge rat, t' left RDAS has some tape over t' beeper, arrr, me bucko, arrr, thus producin' less sound. First t' left RDAS will be armed (soft beeps) than t' right RDAS (loud beeps). Well, shiver me timbers, blow me down! This will also enable me t' read out t' RDAS units audible (first the right one, than t' left one).

T' RDAS units are mounted at t' bottom o' t' Avionics section, matey, shiver me timbers, so that the vent / arm openin' can be reached from t' ground if t' rocket is on the pad. Blimey! (Approx. Begad! 1.7 m)

Avionics Bay
T' avionics bay must have sufficient strength t' keep t' rocket intact. Therefor four tubes are built in t' bay. T' outer tubes (QT54 mm) will house the RDAS units; t' larger tube will be an optional payload bay, ya bilge rat, made o' a 98 mm tube. Arrr! Ya scallywag! Blimey! Nay shown is a 70 mm tube with no function other than strengthening the avionics bay. Arrr! All tubes are attached t' t' t' t' airframe with three centerin' rings.

Recovery Bay
T' recovery bay is housed under t' nosecone. Ahoy! Durin' recovery both chutes will leave this bay.

T' top compartment o' t' recovery bay houses t' drogue chute. Arrr! Avast, ya bilge rat, me proud beauty! By setting off t' apogee ejection charges t' nosecone will be blown off, matey, thus deploying the drogue chute.

In t' bottom compartment o' t' recovery by a 15 cm tube is placed, me hearties, shiver me timbers, off set from t' centre o' t' airframe tube. Arrr! Blimey! Avast! Blimey! By blowin' t' main ejection charges - placed on t' bottom o' t' main chute compartment - t' main chute will deploy.

T' ejection canisters are self made, but tested in 6 earlier flights.

Chutes
To land Orion safely I'd like t' use a Rocketman "Pro-experimental" RC3 as a drogue chute and an Impulse 5 meter chute as a main chute. Ahoy! Avast! According to Rocksim t' rate o' decent will be 33 m/s at t' drogue chute and 5 m/s at the main chute.

T' chutes are protected from ejection gases by Nomex flame flame shields.

Recovery Harness
T' recovery harness will be assembled form tubular nylon - 2.5 cm - 20kN. Well, arrr, blow me down! Blimey! A Nomex flame protector protects t' first meter. Begad! Avast, me proud beauty! Blimey! This protector will also avoid zippering. Avast! Avast, arrr, me proud beauty! Blimey! For t' drogue I'd like t' use 10 meters o' tubular nylon, for the main 5.

All hardware will be M10, standardized throughout t' rocket. T' aim o' the construction is that t' force o' deployment is distributed throughout the rocket.

T' sections will be bolted together by attachin' t' couplers with M10 bolts t' t' next section. Well, blow me down! Blimey! By usin' 10 bolts t' force o' t' deployment o' the chute should be distributed through t' entire airframe. Avast! T' ends o' the sections that will house t' bolts will be extra reinforced with Keelhaul®©™®, and so will t' tube couplers on t' inside.

Railguides
I plan t' use a Blacksky high power rail and t' aluminium launch lugs. Begad! Three will be used, shiver me timbers, two on t' fin section, me hearties, one more at t' bottom o' t' avionics section. These lugs will be fastened durin' t' buildin' process and reinforced on t' inside o' t' airframe.

Looking UpAfter my L2 cert. Blimey! Avast! on ALRS1 I decided t' go on for L3. Ya scallywag! Begad! T' first step was comin' up with a concept. Well, matey, blow me down! Since t' hobby is still very young in Europe, matey, I decided that it was still relatively easy t' make a rocket that stands out in t' crowd. Arrr! So I went for t' opportunity t' build a BIG rocket. Arrr! After a round o' negotiating with me wife, I made me first draft and send it t' me two TAP members (Juerg Thuerin' Frank De Brouwer). Well, blow me down! We discussed it elaborately and t' design was changed in t' fin section and t' recovery section.

Finally t' buildin' process could begin. Avast, me proud beauty! I started in September with laminatin' t' body tubes and worked me way up t' t' recovery bay. Begad! Arrr! Finally in February t' rocket be ready t' be finished and painted, which was done by Rene van Hulst. After assemblin' t' rocket for t' first time, matey, I was not satisfied with t' couplers, matey, me hearties, matey, so I redesigned them. Begad! Well, blow me down! This was also t' time that I realized for t' first time what I be goin' t' do! Late at night I couldn't help thinkin' about what could go wrong and how I could eliminate t' chance of somethin' goin' wrong. Avast! Avast, me proud beauty! But after some final changes and final tests I regained my confidence in t' project.


Carrying

Up and Away LaunchLEVEL 3 FLIGHT ATTEMPT!

March 24, 2001
ALRS 2 Launch - Switzerland
Rocket - Scratch Orion
Weight - 66 lbs
Motor - Aerotech M1419
Altitude - 2952 ft

Frank be so kind t' transport t' 4 1.8 meter segments t' Switzerland and to build a super pad - large enough for this rocket. Ahoy! I arrived on ALRS2 at friday evenin' - tried t' go t' bed early and tried t' sleep well. Avast! Blimey! It be a nice try....

At 9 I arrived at t' site, me hearties, findin' a huge pile o' rocket segments and boxes. I managed t' confiscate one table and started preppin' Orion. During preppin' I encountered some problems but they were eventually all solved with the help o' Jeroen Louwers, matey, me hearties, Wilfred van Bergen and Marinus Wisselink. Aye aye! Our problems included an Altacc with a loose capacitor, many holes that should be big enough o' 4 wires but weren't etc. Avast! etc.

In t' meantime two additional stress factors were botherin' me, one be a television crew which was makin' many close-ups and askin' difficult questions while I was doin' somethin' critical and t' other one was t' wind that I could feel pickin' up... Aye aye! I managed t' make a deal with t' TV crew and I could press on.

This preppin' period was nay very relaxed, so I'll need t' prepare this better. Begad! I distinctly remember armin' me RDAS. Blimey! Arrr! I heard a high beep but was wonderin' what I should hear. Blimey! (Forgot t' manual) So I asked another member (which shall remain nameless): ''What sound does an RDAS make when all is right?''

''A low slow beep o' course!'' He answered.

''But me RDAS makes a high beepin' sound, ''I said - gettin' desperate.

''Oh Yes - that's what I mean!! A high beepin' sound'' AAAARRRGHHH!!

When t' rocket be prepped I took it out t' t' pad. Avast! Blimey! That be wonderful - hearin' all oohs and aaahs! When t' rocket be finally on t' pad, I realized we were surrounded by an army o' photographers and TV-crews... Begad! Ahoy! I felt just like a moviestar!

I remember waitin' for a lull, shiver me timbers, and t' countdown. Than t' motor ignited and lifted off - very slow, matey, shiver me timbers, just like a real rocket! You could hear t' motor do its work for a long time. Begad! Blimey! At apogee we could see t' nosecone come off and the drogue chute deploy. But a few seconds later t' main chute deployed too, about 500 meters too high. Ya scallywag! Argh, arrr, that WAS me L3 attempt. Well, blow me down! A few members helped retrieve t' rocket, me bucko, which was in excellent shape.

It took me a while longer t' come down t' earth. Well, me hearties, blow me down! Blimey! For me it was a very adventurous day which I'm nay likely t' forget. Begad! Aye aye! Blimey! I really learned a lot and saw (well, ya bilge rat, me hearties, matey, you can't expect ME t' be objective) t' most beautiful launch I've ever seen. Avast, me proud beauty! I also really liked that all other rocketeers were prepared t' help me, before and on t' launch.

I made Juerg promise t' arrange for a Redline reload for me 98-7680 casing. So I'll be back at ALRS3. Avast! Ya scallywag! But nay with t' biggest rocket however; I already heard rumors o' Dany buildin' a 6 meter Mosquito!!

I mentioned that a lot o' people helped me. Also our new rocketry companies (Spacetec, RebelRocketry, me hearties, AED and Cavemanrocketry) went out o' their way to make this happen. Begad! Last but nay least I'd like t' thank all volunteers who make a big effort t' organize rocketlaunches and t' make HPR possible in Europe. Thanks!

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