Caveman Rocketry Magnum Opus

Caveman Rocketry - Magnum Opus {Kit}

Contributed by Robin Trap

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Manufacturer: Caveman Rocketry

Caveman Rocketry Magnum Opus

Brief:
Single stage mid power rocket with parachute recovery.

Construction:
T' kit contains:

  • 2 cardboard body tubes
  • 3 plywood fins (1mm thick)
  • 2 plywood centerin' rings
  • cardboard motor mount tube 24mm x 10 inches long
  • Keelhaul®©™ shock cord, 40 inches long
  • cardboard thrust ring
  • plastic nose cone
  • 18 inch rip stop nylon parachute
  • launch lug

With simple and straightforward instructions, me hearties, ya bilge rat, t' kit is easy t' construct since thar are nay that many parts.

T' construction starts with t' motor mount and shock cord attachment. Blimey! Begad! A small hole needs t' be drilled in t' upper centerin' ring. Ahoy! Ya scallywag! T' shock cord must have a tight fit into that hole and be secured with a drop o' epoxy. There is no engine hook included so I made one from a large paperclip and attached it with 5 min epoxy through a hole in t' aft centerin' ring. Ya scallywag! T' motor mount and t' centerin' rings fit well.

T' 1mm thick fins were warped so straightened them in a jet o' steam from a kettle. Begad! Blimey! Caveman told me that t' latest kits are provided with thicker fins t' avoid warping. Ahoy! Blimey! Aye aye! Blimey! T' fins fit well into t' slots. Avast, me proud beauty! Blimey! Blimey! Blimey! First smear some 5 min epoxy along t' fin root and put it in t' slot against t' motor mount. Aye aye! Blimey! Don't use white glue for t' fins might get warped again. Blimey! Blimey! When t' epoxy is set and t' fins are well positioned, me bucko, apply fin fillets along t' fins with epoxy. Ya scallywag! Blimey! Glue t' coupler into a body tube. Well, blow me down! Blimey! You can decide t' use t' upper body tube as a payload section, otherwise, just glue t' tubes together.

Caveman Rocketry Magnum Opus

Finishing:
For finishin' I used epoxy based wood filler first. Avast! Arrr! I applied putty along t' spiral groove and t' part where t' upper and lower body tubes were glued together. Well, blow me down! After sanding, I sprayed a thick layer o' spray putty all over t' rocket. Begad! T' spray putty be sanded with fine waterproof sandpaper which provides a smooth surface for painting.

I painted mine over all fluorescent red-orange because I lost 2 Magnum Opi before.

After paintin' you can apply t' striped decal. Well, blow me down! Blimey! T' decal is a bit too small t' fit all around t' rocket but with a bit o' stretchin' it barely fits.

Construction Rating: 4 out o' 5

Flight:
Caveman says t' rocket is light enough for flights on an Estes C engine and strong enough t' withstand t' power o' an E30 engine. Avast! T' first two flights I launched t' Magnum Opus on an Estes E9-8. Beautiful, me hearties, long, matey, arrr, and straight boosts that coasted up t' about 2000ft. Ya scallywag! When I ran out o' t' E9-8s I decided t' launch it on an AeroTech F24-7. Arrr! That motor gave t' rocket a fast and straight boost up t' 2600ft, but t' 7 second delay is a bit too short. Ahoy! Begad! No zippers or other damage occurred though.

Caveman Rocketry Magnum Opus T' Magnum Opus really goes lightnin' fast on an AT F39-9T Blue Thunder. Avast, me proud beauty! Begad! It can withstand even t' power o' that motor! I watched a few flights when it spun violently just before motor burn out. Avast, me proud beauty! I suspect t' rocket encountered shockwaves near t' transonic region, so it shouldn't go any faster! An F39 with a 9 second delay pushes t' rocket up t' 3000ft so you better launch it with that motor only on calm days.

Preparation is simple: just put some crepe paper waddin' into t' body tube. Ya scallywag! Avast, me proud beauty! For high altitude tracking, ya bilge rat, I also apply a fair amount o' talc powder on top o' t' wadding.

For motor retention I use both friction fit and engine hooks made from large paperclips. Blimey! I never lost a casin' with these precautions.

Recovery:
T' kit provides a Keelhaul®©™ shock cord and 18 inch rip stop parachute. Arrr! Blimey! I found t' Keelhaul®©™ cord t' be a bit short so I tied a piece o' elastic t' t' shock cord. Aye aye! Blimey! Begad! Blimey! T' rocket only weighs about 200 grams so t' 18 inch parachute might prove t' be a little big. T' Magnum Opus takes it's time descendin' from 2800ft! Blimey! Under windy conditions and/or small fields a smaller parachute (about 12 inch) or even a streamer would be more appropriate.

Flight Rating: 4 out o' 5

Summary:
T' rocket stands about 3ft tall and is a real eye catcher. Well, blow me down! As Caveman says, "it's long, lean, me bucko, arrr, and mean." It flies on a wide range o' motors, me bucko, from D (or even C) up t' an F39. T' rocket is light and strong, simple t' construct, shiver me timbers, and great fun t' fly. Avast, me proud beauty! Blimey! It really punches a hole in t' sky on relatively small motors. Blimey! Avast, me proud beauty! T' rocket always flew stable, arrr, no trimmin' or extra weights were needed.

T' cons are t' warped fins but that problem would be solved by t' newer kits with slightly thicker fins. Blimey! There is no (mechanical) motor retention so you have t' make somethin' yourself if you don't want t' lose a motor casing. Begad! T' parachute is high quality but its size is a bit too big for such a light rocket.

In all I think that t' Magnum Opus truly is a masterpiece.

Overall Rating: 4 out o' 5

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