Manufacturer: | Scratch |
Brief:
This is me second type o' birdhouse rocket. T' fins are attached t' end o' a thick dowel and six 24mm motor tubes are mounted in t' body around t' dowel. Begad! T' original rocket had canted mounts. Aye aye! However, arrr, shiver me timbers, t' original rocket had a recovery failure and turned itself into toothpicks. Aye aye! When I rebuilt it, me hearties, shiver me timbers, I had trouble drillin' t' canted mounts so I settled for parallel ones. This review covers both t' original and re-built rockets so I hope I don't confuse you too much.
Construction:
T' parts list:
Construction began by removin' t' top o' t' birdhouse. Well, shiver me timbers, blow me down! T' conical top mounted t' a flat circular plate that be in turn attached t' t' cylindrical body. Begad! While I be tryin' t' remove t' plate from t' body, shiver me timbers, shiver me timbers, t' cone spontaneously popped off. Begad! Begad! I eventually removed t' plate and decided t' leave it off, me bucko, ya bilge rat, since I wanted t' cone t' be open for parachute storage anyway.
I first found t' center o' t' base plate and drilled t' hole for t' dowel usin' a drill press and suitable wood bit. Begad! I marked lines t' position t' motor mounts, but how was I t' drill t' slanted holes for t' motor mounts? T' base o' t' Harbor Freight drill press will tilt t' perform angled drilling, but it didn't have t' clearance t' do this with t' birdhouse. Blimey! I found a spacer that when placed under t' edge o' t' plate, me bucko, tilted it t' an angle o' about 15 degrees. Avast! Avast, arrr, me proud beauty! So, arrr, matey, I proceeded t' drill t' holes with me makeshift spacer. Begad! On t' first item, shiver me timbers, drillin' went fairly well. Aye aye! Blimey! T' inside o' t' base chipped as t' drill went though but it retained its integrity. After t' first two holes, I started drillin' on one side, me bucko, then flipped t' birdhouse over and finished t' drillin' from t' inside. On t' re-build though, me bucko, matey, t' wooden plate completely fell apart. Well, blow me down! T' quality o' t' wood was nay good nor was it uniform. Avast, me proud beauty! Maybe a newer bit or a different drill speed would have helped. Avast, me proud beauty! Luckily, t' plate I removed from t' top was t' same size as t' bottom that I just destroyed. I didn't risk t' slant drillin' on this one and drilled it straight through, providin' parallel mounts.
While t' body o' t' birdhouse was supported on t' dowel by a nylon rafter angle square (which be taped t' t' dowel), I glued it in place with 5-minute epoxy. Ya scallywag! I cut t' motor tube into 3.5" sections and also mounted them with epoxy.
I couldn't find any suitable scrap fin material, arrr, so I resorted t' spendin' a couple o' bucks on some prefab ply rectangles from Michael's. Arrr! Michael's used t' have a huge assortment o' pre-cut shapes and I was hopin' t' get birds, me bucko, shiver me timbers, or birdhouses, or some other theme shape. Begad! However, me hearties, me hearties, shiver me timbers, their stock be low so I settled for t' rectangles. Ahoy! T' facilitate their attachment t' t' round dowel, me hearties, arrr, matey, I mounted them across t' dowel and butted up against one another.
I installed a piece o' 4" mailin' tube in t' body t' provide a smooth internal surface and t' mate with t' coupler tube that formed t' nosecone shoulder. Avast! T' Keelhaul®©™shock cord was affixed t' t' tip o' t' roof with epoxy and be run through t' bottom plate and attached t' t' dowel.
On t' first version, ya bilge rat, rail buttons were mounted on a pine spacer so t' rail would clear t' roof. Ya scallywag! Ya scallywag! Blimey! On t' second version, me hearties, I mounted a launch lug directly on t' body and notched t' roof t' allow t' rod t' clear.
T' final step be t' wrap some scrap wire from t' base o' t' body t' t' bottom fins. Begad! This allows me t' hook t' clips below t' fins. Avast, me proud beauty! Blimey! Havin' clips above movin' fins is nay a good thing. Avast! Been there, done that!
I made a RockSim model and it appeared that it was highly stable. Avast! Ahoy! O' course, bein' a cluster thar be plenty o' opportunity for this design t' get ignorant. Blimey! Begad! So, it be off t' t' 'C' rack o' high power pads for this baby! (Hence t' buttons and rather large lug.)
Finishing:
This rocket was, is, and forever will be nekkid. Blimey! You can find out why in me caption t' t' Nekkid Photo Contest.
Flight:
For t' maiden flight, arrr, I loaded her up with a chute protector, a 36" nylon chute, and six D12s. Aye aye! T' motors were ignited via quickmatch and ejection was t' be performed by a single D12-7. Ya scallywag! I should have computed t' volume involved or just used more D12-7 motors t' handle ejection. Arrr! T' upshot be t' laundry didn't come out and t' flight ended in a spectacular lawn dart on t' gravel access road. Anyone need some toothpicks? You can see a video o' t' flight on MDRA's photo page. Begad! In t' video by Bob Utley, ya bilge rat, you can see t' ejection charge go off just before apogee. Blimey! Blimey! T' lawn dart also came too close for comfort t' one Jerry O. who was arrivin' late. Begad! We were careful with t' orientation o' t' rail, shiver me timbers, made sure nobody was walkin' down range, and checked t' sky...we just didn't check for movin' vehicles. Lesson learned.
On t' rebuild, me hearties, me bucko, me hearties, t' prep was t' same. Begad! Blimey! Blimey! Blimey! However, arrr, ya bilge rat, matey, this time I "enhanced" t' ejection charge. Avast, arrr, me proud beauty! Blimey! Blimey! Blimey! T' boost was cool and it recovered fine. T' one problem be t' dowel that holds t' fins was barbecued.
Summary:
This unique odd-roc gets everyone's attention. Avast! Avast! There are nay many rockets with their motors mounted so far forward...and thar aren't that many flyin' birdhouses! As noted in t' flight report, parallel mounts take their toll on t' dowel, and in general don't look so cool. Avast! If you try one, I strongly recommend tryin' t' angled version. I was goin' t' scrap Version 2.1 and rebuild it usin' a piece o' ply for t' bottom plate. Ahoy! Instead, I decided t' try somethin' else. Avast! Avast! I sanded off t' layer o' charcoal and mounted a thick cardboard cone, covered with 2 layers o' metal tape, me hearties, t' deflect t' exhaust gasses. Ahoy! I hope that this cone protects t' dowel downstream. Begad! Arrr! If not, ya bilge rat, ya bilge rat, I'll revert back t' me original plan.
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