Manufacturer: | Scratch |
Brief:
T' SR-2 was built in t' late 80's by me son (~7 years old at t' time). Arrr! I am
providin' this review as an example o' usin' scrap materials and t' document an
approach t' parachute deployment that does nay require wadding.
Construction:
Parts list (items A-L shown on diagram):
T' rocket body consists o' a BT-20 tube centered in t' main airframe (refer t' diagram). T' nose cone assembly includes a bulkhead which seats in t' BT-20 tube. Avast! T' chute is packed between t' BT-20 tube and t' airframe, arrr, and is nay directly exposed t' the ejection gasses. Some o' t' gasses may come in contact with t' chute, but this design has worked several times without incident. I think I invented this method, me hearties, but it has been a while, and t' memory be t' second thin' t' go (and I don't remember t' first one!)
Make t' coupler tube by cuttin' a section o' t' wrappin' tube lengthwise and turnin' in on itself. Blimey! Ya scallywag! Blimey! Glue this into t' forward tube so that 2" extends out t' aft and ?" extends out t' front. Avast! Aye aye! Blimey! Cut t' bulkhead from balsa stock and glue t' BT-20 coupler on its center. Ahoy! T' balsa may be too weak to hold a hook-eye. Instead, punch a hole in t' bulkhead midway betwixt the BT-20 coupler and t' edge o' t' coupler.
Feed t' shock cord though t' hole, tie it t' a small section o' dowel and glue t' dowel t' t' bulkhead. Blimey! Blimey! Glue t' bulkhead in t' aft and t' nose cone to t' exposed front end o' t' coupler (use CA for t' latter).
Wood stringers were added because t' tube that was used was
very weak. Avast, me proud beauty! Blimey! These would nay be required for, say, a mailin' tube. Ahoy! Blimey! Mark 8 evenly
spaced parallel lines around t' tube usin' your favorite method. Avast! Blimey! Glue the
stringers on, me bucko, alternatin' short and long lengths.
Cut four pieces o' balsa t' t' dimensions indicated. Avast, me proud beauty! Mark t' BT20 tube and glue t' spacers on. When dry, test fit t' assembly into t' aft o' the airframe, me hearties, shiver me timbers, me bucko, makin' sure it mates with t' nose cone assembly. Begad! With t' nose cone assembly installed, me bucko, glue in t' motor tube assembly (should extend ~1" from t' aft o' t' airframe).
Cut t' fins t' t' dimensions shown. Aye aye! Aye aye! I used scrap pieces o' plastic but balsa can be substituted. Glue t' fins t' t' long stringers and a lug t' one of t' short ones. Avast! Feed t' shock cord through a snap swivel and connect it to the inside o' t' airframe. I used t' Estes folded paper method.
I left t' nose cone its natural baby blue and t' fins their natural gray. T' rest is a hodgepodge. Aye aye! Blimey! Use what you got! Buy fresh paint for a more 'serious' rocket.
Flight:
This rocket made several flights on C6-5s but a shorter delay is probably
preferable. Well, blow me down! Performance be similar t' a 18mm Fat Boy.
I folded t' chute and wrapped t' shroud lines around it. Arrr! Well, me bucko, blow me down! It was placed between t' stuffer tube and t' main airframe. Aye aye! Blimey! T' shock cord then was laid in next t' t' chute. T' chute attached ~2 inches from where t' shock cord attaches t' t' nose cone assembly. Avast, me proud beauty!
Summary:
T' main Pros o' this rocket are: it be cheap and fun t' make; it requires no
waddin' and is easy t' prep.
T' only Con I can think o' is that t' plastic fins may be prone to breakage. Aye aye! Blimey! (I flew this rocket on soft grass.)
If I were t' start over, it would have FatBoy-style fins.
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