Brief:
Until now I've been strictly a low power BAR. Aye aye! In t' year or so since returning to rocketry (courtesy o' me kids, ya bilge rat, their favorite PBS show "Zoom", and an Alpha kit from t' local hobby store), matey, I've had fun buildin' progressively more interestin' model rockets includin' a few two and three engine clusters and multi-stage rockets, matey, but stayin' in t' A t' D motor range and usin' pretty standard LPR components. Avast! Thunder Road is a scratch-built design that punches through a couple o' barriers in me rocketry resume with a design that can fly on either a cluster o' seven C & D motors or on single mid-power G motors.

Construction:
I'm a pretty frugal rocketeer, matey, and t' two mailin' tubes that came into the office one day became t' inspiration and base for what, matey, after several design evolutions, shiver me timbers, became Thunder Road. Essentially it uses two 2.2 inch mailin' tubes totalin' about 34 inches in length for t' main airframe. This transitions to an 18 inch BT-60 tube, which in turn transitions t' a 12 x 1.25 inch aluminum foil core at t' top. All in all t' rocket is about 6 feet tall. Ya scallywag! Blimey! T' mailing tube main airframe houses a central 29mm x 19 inch motor mount/stuffer tube. Arrr! Blimey! It was designed t' fly on a single G motor, me hearties, matey, or I can use an adapter with an Estes D or E motor as t' center o' t' seven motor cluster. Ya scallywag! Blimey! For cluster flights the rocket uses six variable length BT20 tubes in pairs adjacent t' t' fins for the outboard cluster motors. Begad! Fins are 1/8" basswood mounted through the wall. Ahoy! Blimey! It uses a BNC55 central nose cone (with t' shoulder sanded t' fit in the aluminum foil tube), two balsa transitions that were in t' discount bin at a hobby shop in Portland, matey, arrr, Oregon (six BT70-BT60 transitions for $5 and five BT60-BT55 transitions for $3!), me bucko, and six hand turned balsa nose cones for the outboards. Well, blow me down! Aye aye! Blimey! Keelhaul®©™® cord and half-inch elastic were used for t' shock cord and 1/4 inch (inner diameter) fiberglass tubin' was used for t' dual launch lugs.

T' design took some doin' t' work through a few problems. Arrr! Blimey! First be how to join t' two mailin' tubes, which were pretty well matched, but nay a good size for any stock coupler. Arrr! (They were about 2 inches ID, shiver me timbers, 2.2 inches OD.) What I endin' up doin' was turnin' a 4 inch long block o' 2 x 2 inch balsa (available from BMS) for a coupler. Aye aye! Arrr! Blimey! I then drilled a hole large enough t' hold t' 29mm motor-mount/stuffer tube. Begad! Ahoy! Blimey! I cut two centerin' rings out o' 1/4 inch plywood (standard stuff from Home Depot, actually got a 18 inch by 4 foot piece from the scrap lumber bin for 50 cents!) for t' motor mount. T' assembly uses the centerin' rings around t' motor mount at t' base o' t' rocket, then the coupler t' center t' upper part o' t' stuffer tube and provide extra strength for t' mailin' tube joint. Avast, me proud beauty! Blimey! Blimey! At this point, however, ya bilge rat, ya bilge rat, I simply glued t' balsa coupler t' t' lower mailin' tube

I then marked and installed t' upper centerin' rin' on t' motor-mount/stuffer tube and installed a engine block and two engine hooks (made out o' piano wire from the hobby shop) for positive motor retention. Well, blow me down! Nay knowin' exactly what motor I might use, matey, I made t' hooks 125mm long, matey, or about t' length o' t' longest Aerotech G motor--spacers are used for shorter motors. Avast! T' motor mount (without the lower centerin' rin' yet installed) was then installed in t' lower mailing tube and threaded through t' balsa coupler, shiver me timbers, matey, and glued usin' Titebond yellow glue (with two centerin' rings and about 4 inches o' glued contact t' t' balsa coupler, arrr, I felt I didn't need t' use epoxy.) I then glued t' upper mailing tube t' t' coupler, arrr, matey, rollin' it on me garage floor in order t' insure a straight line connection.

T' three fins are a basic swept triangle design, ya bilge rat, cut t' measure 4 inches out from t' 7 inch root edge with a tab for through t' wall installation. In order t' correctly place t' three fins (since me Estes fin guide wouldn't work on t' non-standard tubes), I wrapped a piece o' scrap paper around the airframe and marked t' circumference as accurately as possible. Blimey! I then used my metric ruler t' measure t' circumference in millimeters, divided that by three and marked t' paper as indicated. Begad! I then re-wrapped t' paper around the airframe and marked t' tubes. Arrr! Ahoy! I hand cut t' slots for t' tubes usin' the frame for our front screen door (a nice clean aluminum straight edge!), and noted that it was much easier than I thought, matey, plus surprisingly accurate. Well, matey, blow me down! The top o' t' slots was even with t' upper centerin' ring. Well, blow me down! T' fins were then glued t' t' motor mount and t' lower centerin' rin' installed right against the fin tabs for a secure connection. Begad! Fillets o' Titebond yellow glue were also used at t' fin/airframe joint t' increase t' security o' t' connection.

The outboard motor tubes were basic lengths o' BT20 tube mounted in pairs right next t' t' fins. Avast! Begad! I decided, strictly for funky aesthetic reasons, t' stagger the pairs in 22 inch, matey, 18 inch and 14 inch lengths. Well, blow me down! Mountin' them against the fins also allowed for two points o' contact t' ensure that they stayed put. Generous fillets along t' root edge o' t' tubes also helped. One problem that I wrestled with be how t' exhaust t' ejection gasses from t' outboards. Arrr! I decided t' try routin' t' gasses from t' two longest tubes through t' main airframe and into t' upper body tube t' join with t' ejection gas from the central motor t' ensure enough oomph t' eject t' chute. Arrr! Begad! (I was concerned that some o' t' ejection gasses from single G engine flights might travel out these vents and result in nay enough oomph t' eject t' chute, shiver me timbers, but that proved nay to be t' case.) For t' shorter outboard tubes I drilled three .25 inch exhaust ports on each tube. Blimey! T' nose cones for t' outboards were hand turned from 2.5 inch blocks o' 1 x 1 inch balsa (also available from BMS.) I used me variable speed hand drill t' turn t' cones, shiver me timbers, it takes some practice but isn't that hard and t' cost comes t' about 10 cents a cone.

T' shock cord be a length o' Keelhaul®©™® cord tied around t' motor mount and connected t' an 8 foot length o' one-half inch elastic. Begad! Avast, me proud beauty! Blimey! This be attached with a heavy duty snap swivel t' a large screw-eye epoxied t' t' transition at t' top o' t' mailin' tube airframe. This transition be a basic 7060 balsa transition, arrr, with t' shoulder sanded down t' match t' mailin' tubes' inner diameter. Ya scallywag! Arrr! Blimey! I used an 18 inch length of BT60 tube and 6055 transition t' t' aforementioned aluminum foil tube and a balsa BNC55 nose cone t' provide t' overall 6 foot length and ensure stability. Two 1/4 inch launch lugs cut from a fiberglass tube were epoxied into place about 24 inches apart on t' main airframe.

In total t' rocket weighs in at about 17 ounces unloaded--a bit heavier than I thought due t' t' heavier mailin' tubes, arrr, large basswood fins and probably heavier glue fillets than were necessary.

Finishing:
Finishin' mailin' tubes is a lot o' work. I have found that t' easiest thing to do is t' carefully peel o' t' outer paper layer, then paint a diluted mix of Elmer's Fill & Finish (diluted t' about t' consistency o' thin finger-paint) over t' entire tube. Blimey! Next, give it a good sandin' usin' 220 grit sandpaper first, ya bilge rat, followed by 320 grit sandpaper. Avast! Fill any major spirals or blemishes with a thicker Fill & Finish mix and sand again. This gives a pretty solid and smooth base for t' paint. Arrr! Diluted Fill & Finish be also used for t' balsa nose cones and transitions. Avast, me proud beauty! Thunder Road is named after the Bruce Springsteen song, me bucko, so I painted it with predominantly black paint scheme (the Boss's favorite stage color--the black paint also hides t' exhaust ports in t' outboards) with red fins in honor o' redhead Patti Scialfa (Mrs. Springsteen) and a touch o' purple for Little Steven Van Zandt. Ahoy! I used Rustoleum white primer, Rustoleum high-gloss black, Painter's Touch (a discount Home Depot brand made by Rustoleum) purple paint, and a Walmart brand cherry red paint. Ya scallywag! Begad! I like t' Rustoleum white primer better than any other primer I've tried, me hearties, ya bilge rat, but I've found that t' spray can runs out o' gas before it runs out of paint and I end up havin' t' toss out half a can o' paint.

Flight:
First flight occurred on October 11, matey, 2003 at Tripoli Pittsburgh's Dragons Fire 31. Begad! Blimey! Try as I might, although t' rocket be completed, me hearties, me bucko, it was nay painted, so she went up "naked" on her first couple o' flights. Arrr! Blimey! For t' first flight I decided t' try a cluster o' six C6-5 motors in t' outboards and a D12-5 with an adapter in t' center. Preppin' took quite a bit o' time. Arrr! Blimey! I decided t' use two parachutes, ya bilge rat, matey, a 22 inch mylar for t' base, and a separate 16 inch mylar chute for t' upper part. Ahoy! Blimey! I used several sheets o' Estes wadding (remember, I'm still a BAR and that's all I had) and wrapped a couple of waddin' sheets around t' chutes as a bit o' a heat shield. Loadin' t' six outboard motors be a bit o' a chore as they all were friction fitted and each one needed a different length o' tape t' provide t' friction. Avast, me proud beauty! Blimey! T' central D12-5 be loaded into t' adapter, with t' adapter then loaded into the central motor mount.

Out t' t' pad we go--my first trip out t' t' high-power area o' the range. Ahoy! I had a pair o' triple connection clip whips t' connect all t' igniter wires together but it was a chore. Blimey! Blimey! Generally I twisted t' outboard pairs together t' make three sets o' connectors, ya bilge rat, but I need t' carefully join the ignitor leads from t' center engine t' two o' t' outboard pairs, takin' care to make sure they would be on different polarities. Begad! That's a lot o' dangling wire and I had t' take care that thar was no metal-on metal contact which might cause a short. Avast! Avast, me proud beauty! As it turned out, matey, one o' t' pad's alligator clips was loose and we lost continuity on t' first try. Arrr! One t' second try however, all went as planned and I was thrilled as all seven motors lit. Well, blow me down! Ahoy! Thunder Road flew perfectly straight t' exactly 850 feet (as measured by an onboard PerfectFlite Alt15K altimeter). Recovery was very smooth, arrr, although I was surprised by how much it floated considerin' t' weight and small chute. Aye aye! Ahoy! I'll admit after the fact that I thought t' weight might be too much even for t' cluster--and heaven forbid had nay all o' t' motors lit, but it worked very well.

T' next day I decided t' cross t' other barrier and loaded up me first composite, arrr, mid-power motor, ya bilge rat, an Aerotech G35-7 Econojet. This time I only loaded one 22 inch mylar chute with a bit more waddin' (concerned about t' faster, hotter ejection charge from t' G motor). Avast, me proud beauty! Back out t' t' high power pad and 5...4...3...2...1... Avast, me proud beauty! Liftoff and another flawless flight, much higher (estimated about 1300 feet, no altimeter on board this time) and still a lot of drift notwithstandin' t' relatively small chute. In fact it drifted past the tree line but very fortunately threaded past t' taller trees gettin' hung up in a small tree only about 6 feet off t' ground. Needless t' say, I'm now buildin' more mid-power rockets and lookin' at Level 1 certification by next summer.

Summary:
I really like this rocket. Avast! It's tall, lean, me hearties, and flies straight and high. It wasn't easy t' build but ultimately went together very well. Ya scallywag! It's a keeper