Manufacturer: | Polecat Aerospace |
Note: This is a slightly condensed version o' all the information that Mike has produced for his Level 3 project. Avast, me proud beauty! Arrr! Visit his site t' read t' additional information and enjoy additional pictures (and video).
Brief:
T' Polecat (formerly Skunk Works) 10" Bull Pup utilized for me Level 3 Certification.
Parts List
(Kit - 10" Polecat Bull Pup fiber glassed Airframe)
List o' Materials:
(1) Slotted nosecone
(1) 10 boat tail
(1) Body tube - slotted
(1) 18 body tube
(1) 11 coupler
(4) Main fins
(4) guide fins (nose)
(1) Nose bulkhead
(1) Upper electronics bay bulkhead
(1) Lower electronics bay bulkhead
(1) upper centerin' rin' drilled
(1) Lower centerin' ring
(1) boat tail centerin' ring
(1) 98mm motor tube
(2) electronics bay slides
(1) Electronics mount
(4) U-bolts with plates
(24) 1/4-20 nuts
(20) 1/4-20 washers
(4) 12 long 1/4-20 threaded rods
(1) 20 shock cord (apogee)
(1) 10 shock cord (main)
Through t' wall fin mountin' for main and guide fins
Fiberglass molded nose cone, slotted
Fiberglass molded boat tail
Fiberglass and slotted body tube
Baltic Birch fins and centerin' rings
Fiberglass electronics bay
98mm motor mount
Tubular nylon shock cords
Steel u-bolt Shock cord mountin' hardware
Dual deployment
Fully redundant ejection charges
Nomex®
blanket for main and drogue parachute protection
Nomex®
shock cord protectors
17' Domed Mil-Spec Cargo Main Parachute
Fully redundant backup recovery charges
Multi redundant power sources for electronics
External key switches for recovery system arming
West Systems epoxy adhesives used throughout
AeroPac Motor Retention system
Construction Details and
Photographs
After a deep breath t' construction begins...
Step 1 - Electronics bay assembly - 11/29/2003
Forward bulkhead is assembled usin' 1/4 inch all thread (9.25" long) and is attached t' forward bulkhead with 1/4 nut and washer on each side. Ya scallywag! Blimey! At this time two charge holders constructed o' heavy polycarbonate are attached t' both t' forward bulkhead and t' electronics bay cover (aft) with 3/16th nuts and washers.
T' attachment point for t' fore parachute harness is also attached at this time with 1/4 inch steel u-bolts with a washer and 1/4 nut external and a steel plate spannin' t' u-bolt and 1/4 nuts internal All connections tightened.
Step 2 - Upper Centerin' Rin' - 11/30/2003
T' attachment point for t' drogue parachute(s) harness is attached at this time with 1/4 inch steel u-bolts with a washer and 1/4 nut external and a steel plate spannin' t' u-bolt and 1/4 nuts internal.
After sandin' t' roughen up t' end o' t' 4" motor mount tube the centerin' rin' above is attached t' t' motor mount tube with a liberal application o' medium fast Epoxy. Begad! Once dry, ya bilge rat, a second application o' Epoxy is applied t' t' underside o' t' centerin' rin' where it meets t' motor tube. T' nuts attachin' t' harness attachment point (u-bolt) are also epoxied.
Step 3 - Tail cone Assembly 11/30/2003
T' tail cone features heavy fiberglass construction with t' aft centering
ring
glued in place with a very heavy pour o' Epoxy mixed with micro balloons to
thicken t' mixture. A follow up pour o' epoxy was used in t' exterior end of
the tail cone t' seal t' motor mount in place. Begad! A clear flat area be left for
the attachment o' t' 98mm Aeropack motor retention system. Avast, me proud beauty! Begad! An 98mm t' 75 mm
Aeropack motor adapter will be used t' fit t' M1315 motor for t' attempt.
Step 4 - Motor Mount Installation 12/3/2003
T' fore motor mount centerin' rin' is epoxied in place in t' 4-fin can body tube usin' 30 min epoxy. Begad! Before installation, t' entire length o' t' motor mount tube be roughed up with 120 grit sandpaper t' assure good adhesion or t' fins t' t' motor mount tube. Once dry, ya bilge rat, a reinforcin' pour is done from above t' solidify t' connection.
To maintain alignment t' internal motor mount t' middle centerin' rin' is slid onto t' motor tube at t' aft end o' t' body tube/fin canister with no glue. Well, blow me down!
This deviates from t' instructions provided by Polecat and once this rin' is removed, will allow internal visual inspection and reinforcement o' fin attachment t' t' motor tube if deemed necessary. Blimey!
Step 5 - Installation o' guide fins and bulkhead into nosecone 12/3/2003
T' nosecone bulkhead with 1/4" harness u-bolt installed is epoxied into t' nosecone and glued in place with multiple pours o' epoxy mixed with micro balloons t' thicken t' mixture and t' fill gaps. Begad! Avast, me proud beauty!
At t' same time t' 4 birch guide fins are taped in place t' assure proper alignment and are glued in place durin' the same pours indicated above. Thick fillets o' epoxy are done on all internal connection points o' t' fins t' t' nosecone assembly and bulkhead. T' nosecone assembly is set aside t' cure completely. Arrr! Avast, me proud beauty! A hole is left in the nosecone bulkhead t' add nose weight later in t' construction process.
Step 6 - T' electronics sled for t' electronics bay is assembled and populated with redundant electronics, redundant battery holders and connectors 12/3/2003
T' electronics and schematic are installed t' t' 6" x 8" electronics board and t' slides are then glued t' t' board clamped t' dry. Begad!
Step 7 - Epoxy in forward bulkhead and coupler for electronics bay
12/4/03
T' fore bulkhead was epoxied in place 3" inside t' upper section of body tube. T' assure proper alignment, shiver me timbers, t' 9" coupler was glued in at the same time. Arrr! Begad! A reinforcin' pour o' epoxy was made t' t' top o' t' body tube onto t' fore bulkhead. Blimey! Blimey! Care be taken nay t' get any epoxy onto t' charge holder cups or charge wirin' pass through.
A 7/8" hole be bored through t' side o' t' coupler 1 1/2 inch below t' fore bulkhead (inside t' bay) t' install t' single throw, me bucko, shiver me timbers, double pole NEMA switch for external armin' o' t' electronics. Blimey! T' electronics slide was installed and t' removable bulkhead be installed t' assure a proper fit and seal.
Step 8 - Fin Can/Booster - Fin Attachment
All fin slots are sanded t' assure a smooth dry fit o' t' 4 birch fins through t' body tube fin slots and through t' t' motor tube. A laser level is used t' project a true 90 degree parallel line up t' sweep o' t' fin assuring an exact positionin' o' t' t' fins once epoxied t' 90 degrees relative to each other. Well, blow me down!
Epoxy is applied t' each fin root and t' t' upper edge (to glue t' the upper centerin' ring) and each fin is attached t' t' motor tube. Ahoy! Accurate measurements are made betwixt each fin t' assure t' laser system worked (which it did perfectly!) Once dry, t' fin roots t' t' motor tube, t' upper centerin' rin' and inside t' fin slot on t' body tube are reinforced with epoxy fillets for additional strength. Begad!
NOTE: 2 part foam will nay be used as t' rocket is very bottom heavy to begin with.
T' Lower centerin' rin' for t' body tube is nay glued in place pendin' TAP review as t' area will be concealed once attached. Ahoy! Well, blow me down!
(12/7/03 - received approval from Mark Clark TAP t' proceed)
Once all t' internal fins t' motor tube and inner wall o' t' body tube has been reinforced with fillets o' epoxy mixed with micro balloons, t' aft centerin' rin' is glued t' t' fin base, motor tube and t' body tube. Avast! Begad! An fillet o' epoxy is completed on t' other side (aft) t' t' body tube and around t' protrudin' motor tube.
T' boat tail is then affixed t' t' end o' fin can with a generous pour o' epoxy around t' base and where t' motor tube passed through t' final centerin' rin' at t' base o' the boat tail. Aye aye!
1/8 " SS socket bolts will be added later t' further secure t' boat tail t' t' body tube and for visual effect.
T' motor tube is then cut flush t' t' aft centerin' rin' t' accommodate the Aero Pack 98 mm motor retainer. Avast, me proud beauty! Avast! T' Aero Pack retainer is installed as per enclosed directions.
This concludes t' construction o' t' booster assembly.
Step 9 - Finishin' and final construction notes
All parachute harness/shock cords are constructed usin' 5/8"
Quicklinks,
1" tubular nylon with 4 wrap slipknots and epoxy reinforcement at knot
junctions. Avast, me proud beauty! Well, blow me down! Additionally tie wraps are used t' stop frayin' o' ends. Aye aye!
Both t' aft shockcord (20') and t' fore shockcord (10') have 3' Nomex® sleeves over t' shockcord at t' end exposed t' hot ejection gases, furthermore both shockcords are fitted with Nomex® blankets t' wrap t' parachutes in for protection. Aye aye! All parachutes will attach with 1/4 in quicklinks.
T' entire rocket is now assembled and (2 - 1500 series rail buttons are attached with t' aft button attached t' t' fin can 6" above t' boat tail into t' aft body tube centerin' ring. T' fore rail button is attached with internal reinforcement (Epoxy set) at 5" above the upper MM centerin' ring.
20 lbs o' lead shot is added t' t' apex o' t' nose cone for nose weight and held in place with a heavy pour o' o' West Systems epoxy. Well, blow me down! This amount was determined by RockSim and a physical balance o' t' rocket with simulated weight for t' loaded motor on t' aft end.
SUCCESSFUL LEVEL 3 FLIGHT!
January 24, 2003
MWP1
Rocket - 10" Polecat Bull Pup
Weight - 58 lbs
Motor - 98mm Aerotech M1315
Altitude - 3,440
After watchin' t' weather all week and then drivin' through light rain this mornin' t' t' Rainbow Valley launch site, things were lookin' a little grim as to if I was goin' t' be able t' launch today. Avast, me proud beauty!
After goin' through me check list and assemblin' t' AT M1315 motor for the flight, wirin' t' ejection charges, arrr, t' breeze that was blowin' suddenly died out. Arrr! Blimey! Wind was me biggest worry for t' flight as t' rocket is heavy and with the 20 lb's o' nose weight, might weathercock off t' rail with a stiff gust on the nose.
Special thanks t' Ken Sparks for t' ongoin' advise and t' use o' his monster 18' 1500 series rail! We loaded t' beast with a little brute force onto t' rail, me hearties, matey, ya bilge rat, elevated it, shiver me timbers, arrr, armed t' dual FC-877's and then loaded and connected t' igniter t' me ProLaunch long range wireless launch controller and headed back t' t' flight line.
After a 5 second countdown and me mind wishin' I was anywhere else at that moment, me bucko, I hit t' launch button and t' beast fired up! Now if anyone tells you that a Bull Pup can't fly straight, shiver me timbers, this flight ends that argument once and for all!
T' rocket cleared the rail with a wicked tail o' flame and went slowly straight up! Blimey! Nay a single rotation o' t' airframe... I mean straight!!!! Blimey! It was textbook perfect.
A beautiful arc at t' top and perfect timin' and deployment by the FC-877's, with a boom from t' backup charge 2 seconds later... 14 grams o' BP in each charge holder makes a pretty big boom.
My buddies at Trailer Trash Aerospace (Kevin, Marty and Jim)helped me out big time in packin' t' 17 foot parachute for t' flight. Even with 60 ft of 1/2 inch Keelhaul®©™® leash, matey, arrr, t' rocket be under perfect canopy seconds after t' charges fired and landed less than 1/4 mile from t' flight line, ya bilge rat, ya bilge rat, A little scuffed paint, but otherwise ready t' fly again.
Now for t' special thanks (in no specific order)
Thanks you Mark Saunders (BSD Rocketry) for loanin' me t' AT case for the flight! Blimey! Blimey! Blimey! Mark, your t' man!
Thanks t' me buddy, matey, Ken Sparks (SSS Member at Large) for calmin' me down on several occasions, shiver me timbers, for loanin' me t' use o' his most excellent rail and most important o' all for t' great cigar after t' fat lady sang! Thanks buddy, me hearties, me bucko, your t' best!
And finally t' me good friends at Trailer Trash Aerospace. Begad! Your help (and harassment) with this project were invaluable in t' success o' t' flight and specifically Marty and Keven who put disaster scenarios in me head too many times t' count and made me lose sleep worryin' about it many nights...
L3 was a blast!!!!
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M.D. (June 2, 2004)