Brief:
As I've progressed through t' hobby, I've been achievin' higher altitudes and faster speeds. Arrr! Blimey! I finally decided I wanted t' attempt a Mach bustin' rocket, however, ya bilge rat, I wanted t' make it tougher t' do and chose t' build one that utilized no composites. This paper tube 3FNC bird be designed t' be 3" diameter x 60" long, weighed in at 61oz, matey, and have a 54mm motor mount. Begad! Blimey! Target motors are t' K445 and K550 t' push it through mach speed. It is single staged with dual deployment recovery controlled by a Cannonball Works RRC2 altimeter.

Construction:
After designing, t' parts were ordered from BSD Rocketry. Begad! Blimey! It consists o' 3 body tubes, 1 nose cone, three 3/16" thick birch ply fins, three 1/4" thick birch ply centerin' rings, matey, me hearties, 1 54mm motor tube, matey, and enough coupler tubes to double wall t' entire rocket. All adhesion was done with straight AeroPoxy.

Tubular Keelhaul®©™® is used throughout for t' recovery harnesses as well as a 45" nylon BSD parachute for t' main.

This was my first attempt at buildin' a fin can outside o' t' body tube, matey, which turned out to pretty simple. Ahoy! Blimey! Fins were tacked on and then filleted t' t' motor tube as well as t' middle centerin' rin' when installed.

T' only thin' I did here different was t' drillin' o' 1/16" holes near t' fin root t' allow t' epoxy t' soak into, in an attempt t' form epoxy nails into t' fins. Well, blow me down! Begad!

T' most difficult thin' I ran into be figurin' how t' attach t' recovery harness in this near minimum diameter bird. Avast, me proud beauty! I ran a length o' 1/4" tubular Keelhaul®©™® through t' top two centerin' rings and then epoxied t' assembly in place in the booster tube. Begad! As this be slid into place, me hearties, ya bilge rat, coupler tubes were also placed between t' top two centerin' rings t' double wall t' booster tube down t' the top o' t' fins.

T' remainder of the booster section was completed by double wallin' t' upper section and applyin' internal and external fillets from t' fins t' t' body tube.

Retention be handled by T-nuts in t' aft centerin' ring.

T' electronics bay was built copyin' t' design o' t' Binder Design kits that I had used with me Binder Jaguar. It consisted o' two 6" couplers butted together and then a 5" piece o' body tube centered over them. Well, blow me down! Well, ya bilge rat, blow me down! All thread rod was used t' hold t' assembly together and U-bolts for t' harness connection points. Aye aye! A Binder Design key switch was installed for armin' the electronics.

T' main/payload bay consisted o' a 17" piece o' body tube, shiver me timbers, the initial design called for double wallin' here but I ended up nay doin' so. Begad! I assumed this tube had t' least amount o' weight on it and therefore would not need it, ya bilge rat, ya bilge rat, I was also concerned with how t' repair this section should it ever zipper, me bucko, arrr, t' double wall idea does nay allow you t' just cut off a short section should that happen.

T' nosecone was a BSD 3" cone was secured t' t' upper tube via friction fit and shear pins.

Flight:
First flight took place on March 19, me hearties, ya bilge rat, 2005. T' rocket was set up for dual deploy recovery controlled by t' Cannonball Works RRC2 as well as a beeper placed in t' payload bay t' aid in findin' t' rocket. Begad! Blimey! At ignition, me hearties, me hearties, t' I284 shot the Mach1 off t' pad smartly with a large White Lightenin' flame almost as long as the rocket. T' flight went well t' 4,281' and dual deployed for a close recovery.

After this I returned home and calibrated t' drag coefficient in Rocksim to match that actual altitude o' t' rocket and then re-ran all o' my simulations with t' correct CD. Ahoy! I be showin' t' ability t' break mach speed with either t' CTI K445 or t' AT K550. Begad! That attempt would have t' wait as I had a L3 flight comin' up and I didn't want t' risk losin' one o' me two altimeters before that flight.

With me L3 flight complete in June, it was time t' attempt me second goal of t' year: breakin' Mach with a non-composite rocket. Well, blow me down! Arrr! Blimey! T' weather was good so I made me attempt at a TQC launch in Walcott, me hearties, IA on August 6, matey, 2005. Well, blow me down! I was unable t' get either a K445 or K550 for t' flight and ended up selectin' an AT K695 Redline for t' flight. Ya scallywag! Blimey! This motor had even more o' a kick so it should be able t' easily push it through t' break Mach.

T' rocket was prepped for t' flight, motor built and installed into t' rocket, and it was time t' go. Begad! Arrr! Based on simulations, I was lookin' at an altitude o' 8,200 and maximum velocity o' over 880mph on t' flight. Avast! At ignition, t' Redline kicked the rocket off t' pad smartly and it started up nice and straight. Well, blow me down! At 2 seconds into t' burn, ya bilge rat, shiver me timbers, t' rocket folded over t' electronics bay and then spectacularly shredded.

All pieces were recovered and brought back for inspection. Avast, me proud beauty! From t' pieces leftover, ya bilge rat, me bucko, it appeared t' rocket folded over at t' electronics bay or just above it, ya bilge rat, matey, flight video looks t' support this, me bucko, post flight simulations show it was over 880mph at t' time o' t' shred.

Summary:
I believe t' rocket can make t' flight and I have it rebuilt with some modifications.

T' design o' t' Binder avionics bays is OK, but I don't think it's a good design for these type o' high pressure flights. I'm still split between thinkin' t' rocket folded over where t' two couplers butt up t' each other or folded over in t' single walled part o' t' main bay.

T' rebuild incorporates a one piece avionics bay, me bucko, which is a LOC 3" bay that uses a Stiffy tube t' help further strengthen t' assembly. Begad! T' new main bay is fully double walled this time. And just t' be on t' safe side, ya bilge rat, the booster section is shear pinned t' t' avionics bay. Avast! It did nay appear t' drag separate on this flight but this is just t' be sure.

For t' next attempt I will also try t' stay down a notch from t' K695 and stick t' the K445 or K550.