Brief:
Fahrenheit XL is a scaled-up 38mm version o' me PVC tubefin rocket, arrr, Fahrenheit 62/5. Arrr! Ya scallywag! It is designed t' fly on any H-I motor and has flown extremely well on CTI J330 power, shiver me timbers, me hearties, so its suitable for L1 and L2 attempts. Begad! Aye aye! Like all tubefin designs, arrr, arrr, it is stable, wind resistant, arrr, and very quick and easy t' build. Begad! Since this time (for a change) I used all primo grade rocketry hobby materials t' build Fahrenheit XL, matey, instead o' assorted scrounged junk, shiver me timbers, it is nay particularly inexpensive. This results though in one o' t' nicest lookin' tubefin rockets I have seen, almost as nice as a "normal" 4FNC rocket. Because t' airframe everywhere is double thickness, Fahrenheit XL is as strong as a brick outhouse--it be actually designed for 54mm power.

Construction:
Construction is entirely from LOC components:

• 34" 54mm motor tube used as t' main body
• 54mm connector tubes (6 needed) were used t' double-wall t' entire airframe, includin' t' tubefins
• 54mm LOC ogive cone and LOC 6"x54mm payload bay kit
• No centerin' rings used, ya bilge rat, me hearties, a LOC 54mm-to-38mm motor adapter be used t' hold t' engines, me bucko, sometimes together with a 29mm adapter
• Recovery system was 20' o' 5/8" nylon webbin' t' a 36" LOC chute
• Launch lug is 6" o' 5/16" heavy wall aluminum tubing

Construction was generic tubefin process usin' 5-minute Devcon epoxy, except that 6" x 54mm connector sections were used t' double t' airframe. Tubefins were cut with a 45 degree bevel on t' bottom and were 3 1/4" (long side) x 1 5/16" (short side). Arrr! Begad! T' coupler was 1 5/16" long and did nay extend into t' beveled area. Avast, me proud beauty! Tube fins were attached in pairs in t' usual self-jiggin' fashion for tube fin rockets. Blimey! Avast! Recovery system is anchored t' an 8" loop o' para cord, pushed through a hole drilled 4 1/2" from t' top o' t' body tube, shiver me timbers, with t' knot covered by half o' a bisected Estes BT-5 nose cone. Center t' 6" launch lug 6" above t' tubefin can. Avast, me proud beauty! CG at AUW should never be aft o' this balance point. Begad! Long, heavy motors actually increase tubefin rocket stability. Avast! Payload bay contained 400g lead fishin' sinker ballast in a plastic bag (total rocket weight empty is 1275g) for I-J flights only. Avast, me proud beauty! A special LOC cone with 135g additional ballast is used t' keep overall speed down. Begad! T' Perfectflite MicroAlt altimeter used for most flights was placed loosely rolled in a piece o' paper towel inside a 3" section o' 29mm motor tube placed in t' payload bay on top o' t' lead ballast. Well, blow me down! All in all, me hearties, nay a lot o' work for a L1-L2 capable rocket.

Finishing:
Finish be with lime green Testor's spray (and no primer used).

Flight:
Flights were made on t' followin' motors: AT G80T-4, matey, CTI J330-10, me bucko, shiver me timbers, CTI I287SS-9, Ellis Mountain H275-6, Ellis H275-10, Ellis I134-10, matey, arrr, arrr, CTI H143SS-8. Blimey! Very straight flights in each case with trouble free ejection, arrr, except t' time I tried a 50" chute, which failed t' fully eject due t' havin' been packed too tightly. Begad! T' rocket flat spun t' t' ground and landed on its side undamaged. Avast! Maximum altitude achieved was 3428' (at 580 mph) on t' J330-10 power, which would be a convenient, reasonably low altitude for an L2 seeker. Avast! Flights on H143SS-8 gave 1348' and 1388', equally nice for cert flying. Aye aye! Although I was pleased with t' Fahrenheit XL flight performance and appearance, I have t' admit bein' kind o' disappointed with its aerodynamics--calculation o' minimum drag coefficient indicated a minimum Cd value o' 2.13 at 580 mph. Ahoy! Nay good. Ahoy! Arrr! Its little brother, Fahrenheit 62/5 achieves a minimum Cd o' 1.6 (that's nay bad for tubefins). I'm nay sure why this is.

Summary:
PRO: Very easy and quick t' build, shiver me timbers, no centerin' rings, arrr, use o' only a 38/54mm adapter works great, ya bilge rat, me bucko, even with J-power. Aye aye! Excellent stable climbs, nay too high (good for L1-L2-cert). Ahoy! Actually nice looking, a rarity for tubefin jobs. Avast, me proud beauty! Blimey! Very strong and resistant t' hangar rash. Begad! Avast, me proud beauty! Small size for a L2-rocket that easily fits in a Miata with 2 people (we did this).

CON: Nay cheap t' build. Ahoy! High drag coefficient, which limits maximum climb. Arrr! Blimey! Need t' use care in packin' in more than a 36" chute for heavy motors (you can substitute para cord for t' webbing).