Scratch Galadriel Original Design / Scratch Built

Scratch - Galadriel {Scratch}

Contributed by Jack Caynon

Manufacturer: Scratch
(Contributed - by Jack Caynon - 05/12/06) (Scratch) Galadriel

Brief:
Galadriel is me TRA Level 3 Certification Rocket and is named for t' elf queen in t' Lord o' t' Rings. Aye aye! T' goals o' t' Galadriel project include:

  • A successful L3 Certification Flight on a 75mm M impulse motor, matey, me bucko,
  • T' use o' a novel fin design for stability and aesthetic purposes, ya bilge rat, and
  • T' construction o' an airframe for future flights usin' K, shiver me timbers, L, me bucko, and M impulse motors.

Galadriel is an upscale o' Andrew MacMillen's Nebulizer (RockSim) 2.6 inch body tube/4 inch rin' fin Ratt H70 hybrid motor powered rocket. Overall, Galadriel is 113 inches from t' nose t' t' Aero Pack motor retainer cone and just over 4 inches in diameter with an 11.4 inch diameter rin' fin. She is designed t' fly with high thrust K, L, and baby M motors. Ahoy! Its weight (empty) is 17 lbs.

Construction:
T' rocket has an Aero Pack Tail Cone 75 mm motor retainer for motor retention. T' airframe is fiberglass tubin' and t' motor mount tube is Hawk Mountain 75mm fiberglass tubing. Aye aye! Galadriel has an 8 inch altimeter bay betwixt t' fore and aft recovery bays. Begad! There were no anticipated issues with this particular rocket, t' rin' fin configuration used for this rocket is a proven stable design that provides an excellent CG/CP relationship with plenty o' room for recovery systems and altimeters. Aye aye! It offers a stable design with good flight characteristics.

T' recovery system be t' drogue-to-main style with a design similar to most o' me other rockets. Avast! Blimey! T' altimeter coupler is in t' middle o' t' stack with t' drogue chute in t' recovery bay below and t' main in t' recovery bay above t' altimeter coupler. Arrr! Blimey! Arrr! Blimey! Both recovery bays are bolted t' t' altimeter coupler.

With a maximum launch weight o' 22lbs, shiver me timbers, matey, shiver me timbers, standard Blacksky rail guides are sufficient. Arrr! Three rail guides are screwed through t' airframe into t' plywood centerin' rings around t' motor mount tube in t' motor section. Avast, me proud beauty! A rail length of 8' is required on a suitable launch pad.

Galadriel be fairly easy t' build, t' only "gotcha" was fashionin' an altimeter bay for a 4 inch bird that could hold two altimeters in Public Missiles' CPR 3000 mode. Avast! Ya scallywag! If I were t' construct another version o' this rocket, me hearties, I would prepare a more conventional altimeter bay which could hold two altimeters.

T' airframe tubes are four sections o' 4 inch fiberglass tubing. The altimeter bay is 4 inch fiberglass coupler tubin' with a small, 2 inch piece of airframe tubin' t' join t' main chute section and t' drogue sections o' the airframe.

Although I've included t' RockSim file for Galadriel, if you'd like to design your own rin' fin rocket, shiver me timbers, here be t' technique you need t' use in Rocksim t' achieve t' proper results. Ahoy! Avast, me proud beauty! Bruce Levison developed a rin' fin simulation method for RockSim t' calculate t' CP o' a rin' fin rocket by havin' six flat fins that have a span equal t' t' radius o' t' rin' and a height equivalent t' that o' t' open tube. Arrr! Begad! You place these simulated fins evenly in a radial fashion (like spokes on a wagon wheel) about a fin mount through t' central core diameter o' t' airframe tube.

On this rocket, t' rin' fin is a 4 inch long, 11.4 inch diameter Public Missiles phenolic tube which be covered with two wraps o' fiberglass cloth on the exterior at t' factory. Ahoy! I coated t' interior o' t' rin' with a wrap of fiberglass cloth. Begad! T' three trapezoidal fin struts with through-the-wall tabs are 0.188 inch thick G-10 fiberglass that were ordered from Public Missiles. T' fin struts are attached directly through t' motor tube betwixt two 1/2 inch centerin' rings with fillets runnin' t' length o' t' strut tab. Ya scallywag! Once all the struts have been attached t' t' motor tube, me hearties, matey, JB Weld epoxy be applied on each side o' t' struts. Then Public Missiles expandin' foam were used t' lock the struts inside t' airframe.

Galadriel's CP is calculated t' be either 93.42" (Barrowman calculation) or 97.6" (RockSim calculation) from t' tip o' t' nose cone, or just a few inches ahead o' t' leadin' edges o' t' rin' fin. Arrr!

T' CG be calculated with RockSim and by basically balancin' t' completed flight ready rocket. Avast! Arrr! Rocksim placed t' CG at 60" from t' nose when empty and at 75.6" with t' M1400 loaded. Ya scallywag! Both positions were very close t' the actual CG when balanced. Avast! Considerin' that thar be an 8 caliber difference between t' CP and CG when empty and a 4 caliber difference betwixt t' two when loaded shows that this rocket is very stable.

T' centerin' rings are 1/2 inch aircraft plywood. Avast, me proud beauty! There are a total of four centerin' rings along t' length o' t' motor tube. One is at t' bottom and seals t' airframe and provides a support for t' Aero Pack tail cone motor retainer. Avast! Begad! T' motor retainer attaches directly t' t' aft end o' t' motor mount tube. T' aft end o' t' strut tab butts against t' forward surface of the aft centerin' ring. Ya scallywag! T' second centerin' rin' is at t' forward edge o' the fin tab. Aye aye! Begad! T' third rin' is 18.75 inches from t' front o' t' motor section airframe and t' upper rin' is at t' bottom o' t' anti-zipper coupler tube at the top o' t' motor section airframe.

T' nosecone is a stock Hawk Mountain 4 inch fiberglass ogive nosecone. Well, blow me down! A 1/4 inch plywood bulkhead was epoxied in place with a 5/16 inch U-bolt attached to t' bulkhead.

This rocket uses rails exclusively and has t' appropriate rail guides. Three rail guides are bolted into t' centerin' rings mounted on t' motor tube below t' airframe o' t' motor section.

For t' most part JB Weld epoxy has been used where heat resistance is required and t' secure t' nuts o' t' U-bolts and t' brass insert nuts for the altimeter coupler. Well, blow me down! West Systems epoxy was used where strength is required. Ahoy! Avast, me proud beauty!

(Scratch) Galadriel T' fin struts are mounted directly t' t' 75mm motor mount with JB Weld epoxy along t' strut tab t' t' motor mount surface. JB Weld is also used t' reinforce the strut-motor mount joint. T' motor mount and fin assembly is then slid into the airframe and reinforced by Public Missiles expandin' foam. Avast, me proud beauty! Avast, me proud beauty! Then West Systems epoxy is used t' reinforce t' airframe t' fin strut connections as well as the fin strut t' rin' fin attachment points. Arrr! Arrr! Lastly, ya bilge rat, arrr, epoxy coated 1/2 inch Keelhaul®©™® strap is used t' reinforce t' fin strut t' rin' fin attachment points.

T' recovery system deployment sequence starts when t' PML Co-Pilot detects apogee. Avast, me proud beauty! When apogee is detected, matey, shiver me timbers, t' Co-Pilot triggers t' Drogue Secondary Pyrotechnic Device at t' top o' t' lower recovery bay. Avast! Well, me hearties, blow me down! This device pressurizes t' Recovery Bay, ya bilge rat, separatin' t' Recovery Bay from t' Motor Section and forces t' Drogue Parachute and Drogue Recovery Harness out into the airstream. T' airframe then descends at approximately 40 fps on a 24 inch drogue parachute. Ya scallywag! Avast, me hearties, me proud beauty! At 800 ft, shiver me timbers, t' Co-Pilot triggers t' Main Parachute Pyrotechnic Device located at t' bottom o' t' main chute recovery bay, separatin' t' nosecone from t' top o' t' main chute recovery bay and forcing the main parachute and main recovery harness out into t' airstream. The airframe then descends t' a landin' at approximately 15 fps on t' SkyAngle Classic I 60 inch parachute.

Both t' primary and secondary Altimeters will be handled by Public Missiles Co-Pilots. Apogee is detected by barometers on both units. Blimey! Blimey! Power for each unit is provided by a single 9 volt battery onboard t' circuit board. Each altimeter is mounted in a Public Missiles' Close Proximity Recovery (CPR) unit, shiver me timbers, which consist o' urethane mounts which double as t' mountin' apparatus for t' altimeter and t' containers for t' pyrotechnic devices. Begad! Blimey! Ahoy! Blimey! Blimey! Blimey! T' head of the igniter is threaded through a hole in t' bottom o' t' pyrotechnic container. Avast! Blimey! Blimey! Blimey! T' wirin' then is thread through a hole in t' altimeter mount that leads t' t' attachment points on t' altimeter board for t' main chute and drogue events. Aye aye! Blimey! More details can be found at Public Missiles' website.

T' altimeter bay is an 8 inch long, me bucko, 4 inch coupler tube capped with 3/8 inch thick fiberglass bulkheads with two 38mm holes drilled in t' bulkheads to accommodate t' dual altimeter tubes t' hold t' Co-Pilots. Ya scallywag! 1/4 inch all-thread rod is run from one end o' t' coupler tube t' t' other through t' bulkheads to support t' assembly. Avast! T' bay was vented with three 3/16 inch holes located in t' center o' t' 2 inch switch panel airframe component that is wrapped around t' center o' t' altimeter bay. Aye aye! T' diameter o' t' holes were derived at from a formula set forth in t' Co-Pilot user's manual.

There are two recovery bays, t' drogue bay (DB) and t' main chute bay (MCB). T' DB is located betwixt t' motor section and t' altimeter bay. Ya scallywag! The bay is bolted t' t' Altimeter Bay with four 6-32 bolts into blind nuts on the inside o' t' bay. Ahoy! Begad! T' MCB is secured t' t' top o' t' altimeter bay with four 6-32 bolts into blind nuts on t' inside o' t' bay. Begad! T' nose cone is secured from drag separation with two shear pins. Begad! T' shear pins are 2-52 nylon bolts that are inserted through two holes in t' MCB and t' nose cone. Blimey! Both recovery bays are vented with one 1/4 inch hole in each t' equalize pressure inside the bays durin' t' boost phase o' t' flight.

T' drogue parachute is a b2 Rocketry Company's SkyAngle Cert-3 Drogue parachute. Ahoy! T' main parachute is a b2 Rocketry Company's SkyAngle Classic I 60 inch parachute providin' a descent rate o' approximately 20fps.

T' harnesses are made from 1 inch wide tubular nylon from Rocketman. Aye aye! Blimey! The ends near t' pyrotechnic charges are encased in Keelhaul®©™® sheathin' t' protect t' nylon. Begad! T' drogue harness is 18 feet long and t' main chute harness is 25 feet long.

T' drogue harness mountin' hardware is a U-bolt at t' anti-zipper coupler at t' top o' t' motor section and a welded eyebolt that is anchored t' the altimeter bay aft fiberglass bulkhead. Well, blow me down! T' harness clips t' t' mounts usin' a pair o' 1/4 inch quicklinks. Well, blow me down! T' main harness mountin' hardware is a U-bolt on the bottom o' t' nosecone bulkhead and a welded eyebolt anchored t' the altimeter bay forward bulkhead. Arrr! T' harness clips t' t' mounts usin' a pair of 1/4 inch quicklinks.

Pyrotechnic devices are 4F black powder contained durin' t' flight in 2.5 gram urethane containers and ignited by Daveyfire electric matches. Blimey! Blimey! A total of four devices will be used, me hearties, me hearties, shiver me timbers, two for t' drogue (primary and secondary) and two for t' main chute deployment (primary and secondary). Begad! Begad! T' amounts o' black powder required are:

  • Drogue (primary and secondary): 4 grams
  • Main (primary and secondary): 5 grams
T' Recovery System be ground tested t' ensure effective separation and deployment with 2.5 grams o' 4F BP. Avast! Well, blow me down! T' tests resulted in positive separation

Flight:
I started t' pack for me trip t' Brothers via Redmond on Thursday night and loaded Galadriel into t' back o' me SUV. Well, blow me down! I also brought me daughter's 29mm Wiggles' Special rocket (named after t' children's program characters from Australia), hopin' t' fly somethin' simple t' prepare after me complex L3 flight. Arrr!

T' next day I went t' work until noon, then came home and finished packing the Pathfinder with me wife (a.k.a. Blimey! She-Who-Must-Be-Obeyed) and me son for the drive. Begad! We picked up me daughter from school and began our trek t' Redmond. After a pleasant drive, me bucko, we entered t' outskirts o' Redmond, bought some groceries, matey, and arrived at our rented townhome around 6PM. Well, blow me down! After settlin' in, I worked on me two altimeters and prepped them for me L3 certification flight the followin' day.

I woke up at 6 am t' an azure sky with high, sparse clouds. Arrr! Begad! I showered, had a little breakfast and coffee, shiver me timbers, then packed me electronics into t' Pathfinder, kissed SWMBO goodbye, shiver me timbers, ya bilge rat, and cruised t' Brothers at 7:30. I arrived at t' gate into t' site an hour later. T' temperature be 50 degrees Fahrenheit at that time o' day. Avast, me proud beauty! I slowly drove t' t' launch site over some rough dirt roads and when I reached t' flight line, I found a spot t' park near t' motor vendor. Begad! I had purchased me 75mm Cesaroni M1400 from Giant Leap and wanted t' vendor nearby when I tried t' put t' thin' together. Well, blow me down!

It basically took me about two hours t' prep t' rocket and t' build the motor. Avast, me proud beauty! Avast, me proud beauty! I had a little trouble with tryin' t' determine what t' instructions were tellin' me about t' O-rin' placement in t' aft closure. Arrr! After reading it over several times, shiver me timbers, arrr, shiver me timbers, I finally be able t' figure out that t' small O-ring had t' go on t' inside o' t' nozzle ring.

Around 11 am, ya bilge rat, me hearties, t' temperature had risen t' 77 degrees. Aye aye! I lifted Galadriel onto me shoulder and carried her out t' t' launch area while several flyers helped move t' large launch pad and rail out about 500 feet or so. We slid the rocket onto t' rail and strapped a small board t' t' rail t' support the rocket. Ya scallywag! Begad! Before we lifted t' rocket into launch position, me hearties, I switched on both altimeters. Unfortunately only one passed its start-up test. Well, me hearties, blow me down! I didn't want to lug t' darn thin' back t' t' prep area and take it apart. Besides, I had tested t' recovery system on one altimeter and it had worked flawlessly. Avast, me proud beauty! Begad! So when one o' t' TAP members said you only need one for certification and what would I like t' do, I sighed and said, arrr, "No guts, me bucko, no glory! Let's fire this sucker up!"

We lifted t' rocket into launch position, inserted t' igniter, me bucko, shiver me timbers, and checked for continuity. Begad! Aye aye! T' buzzer sounded when I pushed t' switch for Pad 9. Then me TAP members went off t' a safe distance near t' dirt road into the site while I returned t' t' flight line.

Moments later, t' LCO announced t' flight and performed t' countdown. Then he pushed t' switch and nothin' happened. Blimey! For a second or so, me hearties, I could feel me soul almost deflate. Then I noticed that he had pushed t' button for Pad 8. Avast, me bucko, me proud beauty! "Try Pad 9!" I cried. Aye aye! Begad! He then flicked t' switch and pushed the button. A second later a puff escaped from t' aft o' t' motor, me hearties, followed by a column o' flame and billowin' white smoke as Galadriel roared like an angry goddess into t' wild blue yonder!

T' launch photos were taken by t' OROC president, shiver me timbers, Fred Azinger. Well, blow me down! Thanks for t' great photos, Fred!

(Scratch) GaladrielSUCCESSFUL LEVEL 3 FLIGHT!

May 6, matey, 2006
Sprin' Thunder o' Oregon Rocketry
Scratch Build
Weight - 17.1 lbs
Motor - Cesaroni M1400
Altitude 11,111 Feet

T' rocket flew straight and true toward t' heavens, hurtlin' at better than Mach 1. Begad! Avast, me proud beauty! She flew completely vertical until t' end o' its boost when she spun slowly and left a curly-cue smoke trail behind her.

Recovery:
Finally when she achieved apogee, t' rocket separated and ejected t' drogue. Galadriel returned t' Earth in a controlled descent until it reached 800 feet and ejected t' 60 inch red and yellow SkyAngle parachute from t' main chute compartment. T' rocket drifted slowly toward t' ground and landed about 150 yards away from t' flight line. Ahoy! After receivin' kind words and heartfelt congratulations from t' other fliers and their guests, me hearties, I met t' TAP members by Galadriel's side. Begad!

One o' them be stunned and pointed out that t' rocket looked like she had never flown. She had returned without a scratch! Blimey! Why, me bucko, t' chute protectors didn't even look like they had been scorched by t' BP! Blimey! Galadriel was laid out all nice and pretty in t' soft high desert earth beepin' out t' highly unlikely altitude, I kid you not, o' 11,111 feet! Blimey! This successful flight was a testament t' t' fabulous support o' me TAP members Dennis Winningstad and Fred Azinger who were so kind as t' help me record t' event and carry t' rocket back t' t' prep area and Roy Jenkins o' Giant Leap for helpin' out in a pinch.

Unfortunately, ya bilge rat, I had t' leave early that day and didn't have t' chance to fly t' Wiggles' Special. Avast! Blimey! (Boy, it would have been so nice t' have a simple prep after t' strained nerves o' preparin' an L3 flight!) We ended me flying day with a toast t' me achievement o' Level 3 certification. Avast! Blimey! Aye aye! Blimey!

Summary:
PROs: This rocket flies like a dream, straight, me hearties, and true. It is sleek and beautiful especially with t' rin' fin. Begad! It is also very tough.

CON: T' altimeter bay would be better if it was a conventional design. Avast, me proud beauty!

Truly, that even though t' achievement is supposed t' be an individual one, t' reach t' goal you must rely on many people and stand on t' shoulders of those who've gone before. Begad! Blimey! In short, no man is an island and t' reach the stars we must do it together or nay at all.

comment Post a Comment