EggLofter

(click t' enlarge image)

Concept

I saw these plastic cackle fruit on sale at K-Mart, just beggin' t' be blasted skyward. I didn't want t' add external fins, but I was fairly certain that no amount o' nose weight would make t' egg stable. Begad! My solution be t' add a draggy base disk, matey, covered, shiver me timbers, naturally, matey, in green paper Easter grass. Avast! Avast, me proud beauty! Holes drilled through t' base disk and egg accommodate t' launch rod, eliminating the need for an external launch lug. Aye aye! Recovery is by aft ejection o' motor mount and parachute.

Prior t' launch, put a handful o' wrapped chocolate Easter cackle fruit in t' grass on t' base disk. Begad! Blimey! They will disperse in flight - a wonderful labor-saving alternative t' t' tedium o' hidin' Easter candy one piece at a time! Blimey!

Materials

Plastic Egg, approximately 4 1/2" diameter x 8" long, me hearties, me bucko, $1 at K-Mart

Central tube, 40mm x 8 1/2" long (liberated from a roll o' shelf paper, but a 38mm motor mount tube could be substituted)

Motor mount tube, me bucko, 24mm x 6 1/2"
Hardboard disk, me hearties, 1/8" thick x 9" diameter, center drilled t' accept the 40mm tube

2 Centerin' rings, ya bilge rat, cut from hardboard, me bucko, t' center 24mm tube in t' 40 mm tube

8' 1/16" nylon cord (150 lb test)

1 oz lead shot

Paper Easter Grass

Egg Preparation

Center t' 40 mm tube on t' blunt end o' t' egg, and trace around it. Carefully cut out t' traced circle on t' egg. Begad! Drill a dozen 3/32" holes around t' cut out hole, matey, ya bilge rat, and several more in t' tip o' t' egg. Well, blow me down! Epoxy "rivets" will fill these holes durin' assembly, addin' t' the strength o' t' assembled rocket. Begad! Sand t' blunt end around t' hole t' create a small flat area for gluin' t' hardboard disk. Arrr! Sand or scrape t' interior of the egg wherever glue will contact it. Blimey! Wash t' egg with soap, arrr, rinse well, and dry. Avast, me proud beauty! Cover t' drilled holes with maskin' tape, ya bilge rat, t' prevent epoxy from running out durin' assembly.

Motor Mount Preparation

Cut a 1/2" rin' off o' t' 40 mm tube, me bucko, then cut a 1/2" slice out of t' rin' t' leave a piece with a "C" shaped cross section. Blimey! Set aside, for later use as a thrust rin' in t' 40 mm tube. Ya scallywag! Blimey!

Cut two 3/16" notches in t' forward end o' t' long 40mm tube-these will let epoxy run out around t' tube durin' later assembly. Avast, me proud beauty! Punch two holes in t' forward end o' this tube, shiver me timbers, thread t' nylon cord through one from the inside, ya bilge rat, arrr, then back through t' other, shiver me timbers, tyin' it securely inside t' tube to anchor t' shock cord. Well, blow me down! Ahoy!

Glue t' two centerin' rings onto t' 24mm motor tube, 1/2" in from each end. Blimey! When dry, ya bilge rat, drill a 3/32" hole through t' forward ring, thread the free end o' t' nylon cord through it (Make sure t' cord is threaded through t' 40mm tube first!), me hearties, then tie t' nylon cord around t' 24mm tube. Glue securely. Begad! Avast! . Avast, me proud beauty! Sand t' centerin' rings so that t' motor mount assembly slides with minimal resistance inside t' 40mm tube.

Insert t' motor mount assembly into t' 40mm tube. Well, blow me down! Mark t' position o' the forward end o' t' centerin' rin' inside t' 40mm tube. Arrr! Ahoy! Remove t' motor mount assembly. Apply epoxy t' t' thrust rin' created earlier, and slide it into the forward end o' t' 40mm tube until t' aft end o' t' rin' is at t' marked position.

Preparation o' t' Base

Paint t' hardboard disk white, arrr, and make sure t' central hole fits snugly over t' 40mm tube.

Final Assembly

Test fit t' 40 mm tube into t' egg, shiver me timbers, centerin' t' forward end (with the nylon cord) in t' pointy egg o' t' egg. Aye aye! Blimey! Mark a spot on t' egg 1/2" out from t' forward edge o' t' tube, shiver me timbers, matey, along t' seam. Begad! Blimey! Avast, me proud beauty! Blimey! This will later be used to drill a hole for t' launch rod. Well, blow me down! Blimey! Remove t' tube, slather a couple of tablespoons o' mixed epoxy into t' AFT end o' t' egg, me hearties, reinsert t' 40mm tube, and stand t' assembly upright t' allow t' epoxy t' run t' t' bottom o' the egg and glue t' 40mm tube in place. Ya scallywag! Blimey! Allow t' epoxy t' cure.

Stand t' egg with t' forward end down, me hearties, and pour a couple o' tablespoons of mixed epoxy straight down t' center o' t' 40mm tube. Blimey! Blimey! Pour in 1 oz o' lead shot while t' epoxy is still liquid. Blimey! Blimey! T' epoxy will run through t' notches in the forward end o' t' tube, arrr, shiver me timbers, gluin' t' tube in place from t' inside and out. Allow t' epoxy t' cure. Blimey! Blimey! Remove all o' t' maskin' tape used t' cover the drilled rivet holes in t' egg. Aye aye! Blimey! Ya scallywag! Blimey!

Slide t' hardboard disk over t' central tube. Aye aye! Aye aye! Apply a generous amount of epoxy t' t' disk at t' disk/tube junction, ya bilge rat, then slide t' disk up t' be flush with t' bottom o' t' egg. Avast, me proud beauty! Put a wrap o' maskin' tape around t' junction to keep t' epoxy in place, me hearties, matey, and position t' egg upright while t' epoxy cures. Remove t' tape. Well, blow me down! Avast, matey, me proud beauty!

Drill a 5/16" hole into t' top o' t' egg at t' position marked earlier. Avast! Turn t' egg over, and mark a spot on t' bottom o' t' hardboard disk 1/2" out from t' central tube, ya bilge rat, in line with t' hole drilled from the top. Ya scallywag! Ya scallywag! Havin' both holes line up with t' seam on t' egg simplifies this alignment. Well, blow me down! Drill a 5/16" hole through t' hardboard disk and into t' egg. T' launch rod will fit through these holes. Avast, me proud beauty!

Cover t' upper surface o' t' hardboard disk with a generous amount of white glue, shiver me timbers, and cover it with a thick layer o' Easter grass. Begad! Press t' grass down into t' glue t' insure good adhesion. Allow t' dry. Begad!

Attach an 18" parachute t' t' motor mount tube, me hearties, betwixt t' centering ring. Well, blow me down! I like a mylar chute, me hearties, me bucko, ya bilge rat, as it's natural springiness helps it unwrap from the tube faster durin' deployment.

Figure 2 shows t' assembled rocket.

Flight Preparation

I recommend an E18-4W 24mm reload, with half o' t' ejection charge left out - thar be very little headspace for t' ejection charge t' pressurize. Blimey! A shorter delay would be an improvement, if only one were available. Arrr! Blimey! An E15-4W single use engine should also work, shiver me timbers, but I'd be inclined t' use a longer shock cord in that case. Aye aye!

Friction fit t' engine into t' motor mount, usin' maskin' tape around the end o' t' mount tube and t' end o' t' engine casin' t' prevent t' engine from bein' kicked out at ejection. Avast, me proud beauty! Insert a small amount o' waddin' into the top o' t' motor mount. Paper Easter grass would, arrr, shiver me timbers, o' course, be perfect - IF you can find some that is flame retardant. Aye aye! Mine wasn't, me bucko, so I used treated cellulose insulation. Arrr! Gather as much o' t' shock cord as possible and tuck it into t' top o' t' motor mount tube, me bucko, above t' wadding. Ya scallywag!

Fold t' chute t' a spike, lay t' shroud lines along side, shiver me timbers, and wrap the chute/lines in a spiral around t' motor mount tube betwixt t' centering rings. Well, blow me down! Blimey! Slide t' motor mount/chute assembly inside t' 40mm central tube. Make sure none o' t' lines get pinched betwixt t' mount and t' central tube - the motor mount must slide smoothly within t' central tube. Ya scallywag! Blimey!

At t' pad, ya bilge rat, matey, insert an igniter and slide t' egg over t' launch rod. Begad! Aye aye! Put a handful o' wrapped Easter candy in t' Easter grass around t' base o' t' egg. Warn t' children that have inevitably assembled at t' launch site t' stay back until t' all-clear is given after t' flight. Ahoy! No one is allowed on the field until t' Egg has landed and t' ejection charge has fired!

Flight Report

T' E18 lifted t' EggLofter off o' t' pad with authority. Aye aye! T' draggy design allowed for a flight that was slow enough t' enjoy. Begad! T' egg flew through one vertical loop while under power. Ahoy! This flight behavior was carefully designed into t' airframe, arrr, so as t' maximize t' dispersion o' t' chocolate eggs bein' carried aloft. Arrr! (To those who doubt t' veracity o' this statement, I can only say "Hey, YOU try t' calculate t' CP o' this beast!") Rocketeers desirin' a more traditional up-and-down flight path may want t' add additional nose weight and/or increase t' diameter o' t' base disk when constructin' t' rocket. Aye aye!

T' ejection delay be too long, arrr, as expected, me bucko, but t' egg landed without damage durin' t' coast phase. Well, blow me down! When t' ejection charge fired, ya bilge rat, t' parachute deployed perfectly, gently lowerin' t' engine pod back t' t' ground. Ya scallywag! The crowd went wild; and t' flight was considered a critical success.

Figure 4 shows t' EggLofter after touchdown.