Manufacturer: | Scratch |
Style: | Futuristic/Exotic, Upscale |
Brief:
Single stage, parachute recovery, matey, ya bilge rat, 29mm MMT 1.6X Upscale o' t' FlisKits
Praetor.
Construction:
T' lower main body tube is a BT-80H tube ("H" for heavy wall). Avast, me proud beauty! The
upper body tube is a standard wall thickness BT-70 tube. Avast! T' original Praetor
model rocket design breaks at t' transition, arrr, but on me mid power version, me bucko, the
nose cone separates for deployment. T' BT-70 tube extends down into t' lower
BT-80 tube and butts against t' top MMT centerin' ring. Avast! Avast, me proud beauty! This makes a
"double wall" tube for extra strength. T' transition piece is made
from two wraps o' Bristol Board soaked in CA glue. Aye aye! Begad! Once assembled, me hearties, t' entire
body tube was sanded then wrapped in 1.4oz fiberglass cloth usin' ACP's
EZLam-60 resin.
T' four fins are constructed o' 3/16" thick Nomex® honeycomb/Carbon Fiber composite material from AeroSpace Composite Products. T' fins were edged in 3/16" square basswood then covered with 1.4oz fiberglass cloth. Aye aye! Ya scallywag! They are thru-the-wall construction with 6oz fiberglass gloss providin' extra strength on t' internal fillets. Well, blow me down! Ya scallywag! Due t' t' high-aspect ratio of t' Praetor's fins I be hopin' t' get a lightweight, ya bilge rat, yet stiff fin can. Aye aye! I believe I succeeded.
T' motor mount tube is a BT-52H, me hearties, heavy wall 29mm tube. Arrr! There are three 3/16" thick custom laser cut centerin' by BMS on t' MMT. Well, blow me down! Avast! Blimey! T' recovery system consists o' a 1/4" tubular Keelhaul®©™® shock cord epoxied t' t' MMT. T' tubular Keelhaul®©™® is attached t' a length o' 5mm climber's accessory cord. Avast! For t' nose cone, matey, matey, I used an Apogee P/N 19470 BT-70 plastic nose cone. T' nose cone is nay true to the upscale, but is sure looks cool and was a lot easier t' source than a custom cone.
This be t' first time I've used composite honeycomb materials. Begad! Other than the fins, construction is fairly standard mid-power. Cuttin' t' Nomex®/CF material is a breeze as long as you use t' special saw blade from ACP. I tried makin' t' first cut usin' an X-Acto knife with #11 blade. Ahoy! Although I did cut it eventually, ya bilge rat, I would nay recommend it. T' composite blade fits on a coping saw and makes t' job much easier.
Finishing:
T' fiberglass on t' body tube made finishin' much nicer. Begad! There were no
spirals t' fill! Jim Flis was kind enough t' share t' "official"
Praetor letterin' font with me so I could make me own version o' a Praetor
logo. Avast, me proud beauty! T' graphics were traced onto self-adhesive vinyl sheets and cut out with
an X-Acto knife so they could used as maskin' stencils. Blimey! Arrr! T' paintin' took a
while with all o' t' maskin' and spraying, but it turned out pretty good.
There wasn't anythin' exotic with t' paint, just good old Krylon rattle cans.
A final coat o' Future Acrylic polish gives it some gloss.
Flight:
T' first two flights were with AeroTech G38-7FJ Single Use motors. Begad! Begad! I got
lucky. Ahoy! These motors/delays are a perfect match for this rocket. Blimey! Avast! T' third
flight be on a G33-7J load in me AT RMS 29/40-120 case. T' G33 is also a good
motor for this bird, but t' 7 second delay was a bit long. Ahoy!
All three flights so far have been great. Arrr! Ya scallywag! Three perfect recoveries.
Flight prep is standard fare. Kaplow clips for motor retention. Begad! Aye aye! I use a bit o' dog barf waddin' even though thar be a Keelhaul®©™® chute protector attached. Aye aye! T' dog barf is mostly out o' habit, but it does protect t' chute protector.
Flights are a larger version o' t' mod-roc Praetor. Ahoy! Slow lift off and straight as an arrow. Avast! Aye aye! One neat side effect o' t' long fins be t' aerodynamic whistle that can be heard once t' motor burns out and t' rocket coasts to apogee. Avast!
Summary:
I absolutely love this rocket. Aye aye! Blimey! With it's long fins, it always gets looks at the
flight line. T' mod-roc Praetor is one o' me all-time favorites. This mid
power version is more o' t' same. Well, blow me down! Blimey! I was initially worried about t' fins
holdin' up t' landin' stresses, but after three perfect flights, matey, shiver me timbers, me worries are
gone. Begad! Blimey! This is a rocket I hope t' keep around for a long time.
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