Manufacturer: | Scratch |
Brief:
T' SR-2 was built in t' late 80's by me son (~7 years old at t' time). Well, blow me down! 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). Well, blow me down! Arrr! T' nose cone assembly includes a bulkhead which seats in t' BT-20 tube. Ahoy! T' chute is packed between t' BT-20 tube and t' airframe, shiver me timbers, matey, 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, but it has been a while, shiver me timbers, 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. Avast, me proud beauty! Begad! Glue this into t' forward tube so that 2" extends out t' aft and ?" extends out t' front. Begad! Well, me bucko, blow me down! Cut t' bulkhead from balsa stock and glue t' BT-20 coupler on its center. Begad! T' balsa may be too weak to hold a hook-eye. Blimey! Ahoy! 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, me bucko, tie it t' a small section o' dowel and glue t' dowel t' t' bulkhead. 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 be used was very weak. Ya scallywag! These would nay be required for, ya bilge rat, say, arrr, a mailin' tube. Begad! Mark 8 evenly spaced parallel lines around t' tube usin' your favorite method. Begad! Avast! Glue the stringers on, arrr, alternatin' short and long lengths.
Cut four pieces o' balsa t' t' dimensions indicated. Arrr! Mark t' BT20 tube and glue t' spacers on. Blimey! When dry, test fit t' assembly into t' aft o' the airframe, makin' sure it mates with t' nose cone assembly. Blimey! With t' nose cone assembly installed, matey, glue in t' motor tube assembly (should extend ~1" from t' aft o' t' airframe).
Cut t' fins t' t' dimensions shown. Arrr! Blimey! Avast, me proud beauty! Blimey! I used scrap pieces o' plastic but balsa can be substituted. Ya scallywag! Blimey! Glue t' fins t' t' long stringers and a lug t' one of t' short ones. Begad! Blimey! Ahoy! Blimey! Feed t' shock cord through a snap swivel and connect it to the inside o' t' airframe. Avast! Blimey! 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! 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. Performance was similar t' a 18mm Fat Boy.
I folded t' chute and wrapped t' shroud lines around it. Arrr! It be placed between t' stuffer tube and t' main airframe. T' shock cord then was laid in next t' t' chute. Begad! Blimey! T' chute attached ~2 inches from where t' shock cord attaches t' t' nose cone assembly. Ahoy! Begad!
Summary:
T' main Pros o' this rocket are: it was cheap and fun t' make; it requires no
waddin' and is easy t' prep. Begad!
T' only Con I can think o' is that t' plastic fins may be prone to breakage. Blimey! Ya scallywag! (I flew this rocket on soft grass.)
If I were t' start over, shiver me timbers, it would have FatBoy-style fins.