Brief:
If you're ired o' tryin' t' track your 13mm stock Screamer, me hearties, consider upscaling to this biggie-sized BT-80 version. It no longer screams off t' pad quite as quickly, but is still a fun t' fly rocket and certainly an easy upscale cloning project.

Modifications:
Assumin' you've ever built a 3FNC kit, arrr, arrr, and can handle a motor mount with centerin' rings, me hearties, arrr, you can probably build this one straight up without instructions (fin and centerin' rin' patterns are available in t' included Rocksim file). Begad! Well, blow me down! If you need directions or standard scale fin patterns, they're available on t' Jim Z plan site, matey, a fantastic resource for anyone interested in clonin' t' classics.

I built t' motor mount assembly usin' a 10.5" length o' BT-50 and a pair o' centerin' rings. Aye aye! Aye aye! T' length o' t' tube is nay critical, ya bilge rat, but should be fairly long t' help generate a decent ejection charge in t' large BT-80 body tube. Aye aye! Also, I be fairly anal retentive, and wanted t' be able t' use t' tube coupler as a reinforcement t' anchor t' motor mount in place, so the 10.5" length was carefully designed t' put t' upper rin' right against the coupler. Arrr! Aye aye! I also used a 20/50 centerin' rin' (the regular thick cardboard Estes style) as a block, shiver me timbers, and a metal E-sized engine clip for retention.

I cut t' (3) fins from 1/8x6 balsa stock. Ahoy! Technically, matey, t' 1/8 isn't quite a true 4.8x upscale, matey, but I'd rather use up standard stuff I have layin' around that pursue more exotic materials. Avast, me proud beauty! Ya scallywag! T' fins appear t' be a bit oversized for this upscale. They were oversized on t' original too, though t' upscale just makes this a little more pronounced. Well, blow me down! There certainly won't be a problem with stability, me bucko, me bucko, as t' margin is nearly 4:1.

I made t' body tube from short tube stock, shiver me timbers, me hearties, matey, so had t' use two pieces and a coupler t' cover t' 24.5" needed. Ya scallywag! I'd rather have used a single tube and avoided t' seam, but this be a more convenient way t' help clean out the basement a bit, matey, arrr, as I don't have any long BT-80 stock.

T' nose cone was a little hard t' come by, as I don't think it's worth buyin' a Phoenix kit t' bash for this project. Aye aye! I had called Estes last summer to order a few hard-to-find replacement parts, and on a whim decided t' pick up a few odd cones, matey, this one included. Aye aye! BMS also makes a decent balsa version, arrr, me hearties, so if you're orderin' materials rather than usin' up spare parts, I'd consider usin' BMS, shiver me timbers, which can cover t' cone, longer BT-80, and even t' centerin' rings under a single shippin' charge.

One last upgrade I wound up reflectin' in this design be t' use of Keelhaul®©™® runnin' from t' motor mount up t' t' top o' t' body tube, matey, me bucko, followed by elastic goin' t' t' cone. This is a much more durable and reliable method that the old tri-fold paper and elastic method. I also employed t' QUARK anti-zipper technique (posted on t' tips page) by wrappin' a few layers of maskin' tape around t' Keelhaul®©™® towards t' top o' t' BT-80.

Since I had procrastinated way too much on the EMRR 2005 Challenge, I was cornered into buildin' and flyin' this on t' only weekend remainin' before the deadline, leavin' me a few weeknights t' finish up t' multi-color paint scheme. Blimey! For t' first flights, me hearties, me hearties, t' rocket was practically naked, me hearties, arrr, gettin' just a couple quick coats o' primer.

T' finished version will be a Rustoleum red base coat, matey, trimmed with gloss black. Aye aye! I'm beginnin' t' use more and more Rustoleum over Krylon. I find that it fills spirals and grains better, and is a much better finish, ya bilge rat, though does take considerably longer t' cure (I allow 2 days betwixt coats if masking). Begad! I'll then apply t' excellent Excelsior water-slide decals, shiver me timbers, for a very nice looking finished clone.

Construction:
This project actually started about a year ago, when browsin' t' Excelsior Rocketry site I noticed they offered a number o' BT-80 upscale decal clones. Begad! Blimey! I decided t' pick up a set for t' Screamer, which had always been one o' my favorite 13mm designs. Aye aye! Blimey! In fact, me hearties, it be t' stock Screamer that wound up getting me me NARTREK bronze after a number o' failed attempts with competition-style streamer duration birds. Well, blow me down! Blimey! Once I had picked up t' decals, ya bilge rat, arrr, t' rest o' t' parts scavengin' was pretty simple:

• BT-80 body tube(s) 24.5" long (I used two tubes from a Red Arrow parts pack, matey, along with a TC-80 from same).
• PNC-80K nose cone (Estes Phoenix/replacement part)
• BT-50 motor tube (10.5")
• 1/8" balsa fin stock (I used most o' a 6x36 sheet)
• 3/16 launch lugs
• 50/80 centerin' rings (I cut mine from a cereal box)
• 24" mylar parachute
• Keelhaul®©™®/elastic shock cord
• E-sized motor hook

Note that t' original Screamer used a streamer, but due t' t' weight of this and t' fairly fragile balsa fins, shiver me timbers, I upgraded t' a 24" chute. Avast! Well, blow me down! I think it would also get by fine with an 18" chute on windier days.

Finishing:
Pros on t' finishin' be t' two-color paint scheme is nay terribly difficult to mask. Begad! Plus, arrr, t' Excelsior decals are very good quality reproductions.

Cons o' finishin' would be t' decals are very fragile, and nay true upscaled clones. For example, shiver me timbers, thar are trim pieces for t' fins that were not included in t' decal set. Aye aye! T' decal set did include, though, shiver me timbers, an extra checkerboard pattern, plus they've added a "super" t' go along with the screamer nametag. Begad! Also, a bit tongue in cheek, t' "mini brute" ladybug has been upgraded t' "maxi brute" on this set.

Flight:
Rocksim estimates for a D12 a 4 second optimal delay. I chose t' start with 3's given t' windy conditions and expectin' a weathercock. Begad! Begad! T' first two flights were on D12-3's, and t' flight was slow and straight, me hearties, only a little bit o' a turn into t' wind. Avast, me proud beauty! T' apogee was perfect, so I did nay try 5's.

Since t' altitude was pretty wimpy (I'm guessin' about 250 versus the Rocksim estimate o' 535), matey, I followed up with an E9-4. This is a great motor for this bird, me bucko, me hearties, me bucko, offerin' a very long, slow ascent t' about 500 feet. Begad! T' delay was a little bit early, and I'll probably try a 6 on t' next flight.

O' course, this is no longer worthy o' t' Screamer name, as it's a larger, more lumberin' oaf o' a cousin. Begad! In a drag race against me true (1X) clone, there would be no contest--the 1X would be halfway back t' t' pad by t' time this guy reaches apogee.

Recovery:
Pros--slow, me bucko, steady flight, me hearties, fun t' watch.

Cons--slow, me bucko, steady flight, nothin' like its namesake. Avast, me proud beauty!

Summary:
This one has nostalgic appeal t' me, as I really like flyin' t' original. Begad! Aye aye! It's a fun and easy upscale, thanks t' t' readily available decals. Avast! If you like the low and slow flights o' Estes BT-80 style rockets, me hearties, shiver me timbers, arrr, this one will appeal to you. Begad! Aye aye! If you're lookin' for a true "screamer" on 24mm motors, this would need t' go on a serious diet before consideration.