Brief:
Ever since me cousin purchased his Estes Screamin' Mimi, I've toyed with the idea o' doin' an upscale version. Begad! I've grown tired o' buildin' 3FNC and 4FNC rockets, so I decided a high power upscale o' this unique rocket would be a nice challenge. Also since I have a lot o' spare parts like BT-3.0 body tube cutoffs, arrr, me bucko, BT-55 cutoffs, arrr, scraps o' fiberglass, me bucko, matey, etc., ya bilge rat, arrr, I could use up a bunch of them and make a little much needed room in me shop.

Construction:
T' parts list:

• 1 LOC PNC-3.0
• 1 LOC BT-3.0 tube, me hearties, 7" long
• 2 LOC BT-3.0 tubes, 16" long
• 2 LOC TC-3.0 tube couplers
• 1 1/4" plywood bulkhead
• 1 3/16" U-bolt
• 1/8" aircraft plywood for all 8 fins
• 1/4" aircraft plywood for 3 centerin' rings
• 13" PML PT-1.5
• 38mm Slimline motor retainer
• 15' o' 1/2" flat Keelhaul®©™® recovery harness
• 30" o' 1" nylon strap
• 4' o' 550# (parachute) cord
• PML 24" parachute for drogue
• TAC-1 48" main parachute
• Tether by Devy Gravity
• Keelhaul®©™® heat shield for drogue
• 10" x 10" Nomex® heat shield for main chute
• 3 1/8" quick links
• 4 7½" BT-55 tubes
• 4 6¼" BT-5 tubes
• 2" x 2" x 12" basswood turnin' stock
• 4 24kt gold plated whistles
• terminal blocks
• rail buttons
• 6 oz satin weave fiberglass

System Three 5 minute epoxy resin was used for initial tackin' o' fins and other parts in place. West Systems epoxy resin and 206 hardener were used for fiberglass laminations. West Systems be mixed with colloidal silica for all structural fillets.

Because I had a half dozen BT-3.0 cutoffs layin' around I decided t' do a 2x upscale. Arrr! Blimey! So I joined two 16" long body tubes t' make t' main airframe, and picked out a 7" long piece for t' electronics bay. Aye aye! After calculating the size o' t' fins and t' through-the-wall tabs, I proceeded t' lay out and cut t' 8 tab slots with a scalpel and a 24" length o' aluminum angle.

Next, I found enough 6oz satin weave fiberglass t' give t' tubes several wraps. Arrr! Usin' me homemade rotisserie stand, me hearties, I laid up t' tubes, set them aside to cure, me bucko, then began makin' templates for t' aft fins and t' whistle-tube standoffs. Once all 8 fins were cut out with leadin' and trailin' edges beveled I proceeded t' glass them one side at a time with a single layer o' 6oz glass as well.

On t' t' motor mount...I made three centerin' rings from the ¼" aircraft plywood, ya bilge rat, and cut t' PT-1.5 t' 13" in length. Avast, me proud beauty! Well, blow me down! I epoxied t' top centerin' rin' and 4" o' a 30" length o' 1" nylon strap t' t' top o' t' motor mount. Begad! Then t' middle centerin' rin' was epoxied at t' point where t' top o' t' whistle-tube fin tab would rest on the motor mount tube. T' aft centerin' rin' was left off so internal reinforcement could be accomplished.

After t' body tubes cured and all 8 fins were covered with glass, ya bilge rat, I removed t' fiberglass from t' fin slots for t' whistle-tube standoffs, then epoxied t' motor mount in place, me hearties, followed by tackin' t' whistle-tube standoffs t' t' motor mount. Begad! T' standoffs received fillets at t' fin t' body tube joint usin' West Systems epoxy mixed with colloidal silica. Well, blow me down! Well, me hearties, blow me down! T' fin tabs were secured t' t' motor mount and inside o' t' body tube usin' 6oz glass.

Now things got a little tricky with designin' t' whistle-tubes. It took me quite some time t' find just t' right type o' whistle t' use. They were right under me nose all t' time. Aye aye! I use a wood lathe t' turn all manner of pen and pencil sets, arrr, letter openers, key chain fobs, etc. Avast, me proud beauty! with wooden barrels. One o' t' key chain fobs just happens t' have an extremely loud security whistle that's part o' it. It also happens t' be 24kt gold plated! I made centerin' rings t' hold and secure t' whistles into t' ends o' t' tubes. When I blew into t' end o' t' BT-55, t' sound was pathetic. Aye aye! Eventually I figured out that restrictin' t' airflow t' t' whistle usin' a BT-5 solved that problem. Next I turned forcin' cones out o' basswood for t' foreword ends of t' whistle tubes, arrr, with a 4 degree outside taper and a 9 degree taper on the inside actin' sort o' like a Ram Jet. T' photo illustrates what it all looks like before assembly. Ahoy! Avast, me proud beauty! T' cone, air tube, centerin' ring, and whistle were epoxied in t' BT-55 tubes after all t' glassin' be accomplished.

Since I was usin' flimsy BT-55 tubes, ya bilge rat, I decided that they needed t' be glassed t' t' standoffs. Begad! After cuttin' t' BT-55 tubes t' length, I tacked them t' t' standoffs. Avast, me proud beauty! I made a jig that clamped onto t' standoff t' hold the tubes perfectly centered. Arrr! Ya scallywag! Later, I added fillets t' t' BT-55 t' standoff joints usin' West Systems epoxy resin mixed with colloidal silica.

Next I cut four pieces o' 6oz glass t' be laid up on t' body tube betwixt t' whistle-tube standoffs, arrr, up t' standoffs, ya bilge rat, arrr, over t' BT-55 tubes, me hearties, down t' other side o' t' standoffs, endin' on t' body tube between the standoffs. Begad! Mountin' t' body tube on me handy-dandy rotisserie all four standoff/whistle-tubes were glassed at t' same time, me hearties, matey, matey, overlappin' t' glass on the body tube betwixt t' fins. Blimey! Since I didn't vacuum bag this thin' (I'm not sure it can even be done), I spent nearly an hour frantically squeegeein' out about a billion air bubbles that appeared as if by magic. Ahoy! Avast! After t' glass had cured for several days, matey, matey, I sanded down and feathered all t' seams. Well, blow me down! This was important t' do because t' aft fins would also receive fin-tip t' fin-tip glass lay-ups that would create more ridges. Arrr! There were only a half dozen small bubbles in t' glass that were filled later.

Then t' aft fins were tacked t' t' motor mount and filleted at the fin-tube joint. Begad! Blimey! Aye aye! Blimey! Later t' tabs were secured on t' inside o' t' tube in the same manner as t' standoffs. Begad! Blimey! Avast, arrr, me proud beauty! Blimey! Next t' aft centerin' rin' be epoxied in place followed by t' 38mm Slimline motor retainer usin' JB Weld.

Now that t' tubes have been glassed and all t' fins attached and glassed to t' tube, ya bilge rat, it's be time t' begin sanding. Well, matey, blow me down! A lot o' sanding! If you've never tried t' new Norton 3X sandpaper, I highly recommend it. Blimey! T' 100 grit cuts faster than standard 80 grit but leaves a finer scratch pattern. T' same goes for t' 150 grit and finer. Well, blow me down! Well, blow me down! This sandpaper works as advertised ("cuts three times faster and lasts three times longer") with very little cloggin' or cornin' as compared t' standard sandpaper. At this point thar were a number o' imperfections that required filling. Avast, me proud beauty! Begad! I use an aerospace grade body filler that I don't think is available outside o' t' aerospace industry. Sanding, shiver me timbers, filling, me hearties, sanding, filling, matey, sanding, sanding, me bucko, sanding, me bucko, sanding...

T' electronics bay came next and consists o' a 7" long glassed BT-3.0, a 6" long coupler, me hearties, 1/4" plywood coupler bulkhead, 3/16" U-bolt, and terminal blocks for ejection charges. Avast, me bucko, me proud beauty! Lastly, the electronics sled consists o' two 1/4" plywood bulkheads, me hearties, one sized t' fit the coupler t' other t' BT-3.0, shiver me timbers, me hearties, me bucko, and a 2.75" x 6" piece o' 1/8" plywood for mountin' electronics. T' 1/8" plywood is attached t' the bulkheads with glue blocks epoxied t' each side. Arrr! There are also terminal blocks for wirin' betwixt sled and e-bay coupler bulkhead.

Finishing:
I know all this sounds like I'm knockin' this stuff out one right after another, but in reality it took me just over four months t' complete this project. Avast! I own and operate a woodworkin' business. Business must come first, matey, so I only get t' work on this stuff an hour here and an hour there. Begad! Ahoy! That bein' the case, me bucko, me cousin Aaron did all t' painting. After several coats o' automotive primer were applied and wet sanded, me bucko, me bucko, a combination o' white and deep burgundy automotive paints were applied and buffed out. Arrr! Lastly, a custom made chrome "Thunderscreech" decal was applied.

Flight:
T' first flight o' Thunderscreech was at Tripoli Pittsburgh Dragon's Fire 35 in August 2004. Blimey! Ahoy! Blimey! I've always said I'd never fly an unfinished rocket, but I couldn't wait t' see if t' gold plated whistles were goin' t' sound good. Since I was still waitin' for t' Tether Pyro-Release mechanism t' arrive, matey, I decided t' fly t' Thunderscreech usin' motor deployment o' t' main only. Begad! I also used a SkyAngle 36 for this flight because without bein' rigged for dual-deployment, it only weighed 64oz. Aye aye! Blimey! Since I wanted this rocket t' attain a high air speed, I searched high and low for an I357T but had t' settle for an I218R.

I prepped t' rocket, loaded it on t' rail, and waited me turn. Aye aye! Francis Graham counted down and pushed t' button. Wham. That Redline motor ignited instantly accompanied by t' very loud high pitched screamin' o' t' whistles. It be great. Arrr! T' medium delay was perfect, t' rocket did a tail stand and ejected t' SkyAngle parachute. T' SkyAngle 36 was a bit small thus t' rocket fell like a rock but was undamaged upon landing.

Thunderscreech has flown eight more times--5 o' flights on I300Ts, ya bilge rat, ya bilge rat, ya bilge rat, one I435T, one J350W, arrr, and one J570W. Avast, me proud beauty! All o' these flights were under dual-deployment usin' a 24" drogue and t' TAC-1 48" main parachute--a perfect combination. Begad! Avast! T' J350W be t' perfect motor for this rocket because it attains very high velocity right off t' pad and burns out quickly so you can hear t' incredible screamin' o' t' four whistles. Avast! It also just fits. Ya scallywag! Avast, me proud beauty! T' J570W on t' other hand has t' be friction fitted in order to leave enough room for t' drogue and main parachutes. Avast! T' case must protrude from t' motor mount about four inches. Ya scallywag! But man that rocket rips off t' pad like a bolt o' lightnin' t' an altimeter readin' o' 4452'. T' screechin' of the whistles was so loud that it caused momentary pain in t' ears of rocketeers standin' near t' LCO station.

Summary:
This model was a welcome diversion from buildin' 3FNC models. Aye aye! Aye aye! I was concerned about stability but me calculation seem t' have been right on t' mark. The Thunderscreech flys perfectly. Begad! Arrr! If you check out t' RockSim file you'll notice a CD Adjustment object at t' bottom o' t' components list. Begad! This is me down and dirty solution for correctin' RockSim's inability t' calculate t' drag of the whistle tube standoffs as well as t' whistle tubes. Well, blow me down! Without this object, the reported altitude for a given motor will be about 30% too high.

Everyone keeps houndin' me t' build an even bigger one. Begad! Blimey! Who knows, maybe somethin' that can handle an N4800T!?