Brief:
My Tubular Crayon is a single stage HPR rocket usin' parachute recovery. It is based on t' RalphCo type Crayon Bank 4 inches in diameter and 35 inches long. I found t' banks on sale at Toys R Us for $5.99. Ya scallywag! Blimey! I decided t' use tube fins instead o' t' usual clear fins.

Construction:
T' six tube fins are made from two extra crayons. T' motor tube is 54mm with a Slimline retainer. Aye aye! Aye aye! There are three centerin' rings for 3.9 inch tubes. Aye aye! Aye aye! I used a 3.9 inch bulkhead in t' nosecone. T' chute is a Rocketman R7C in a deployment bag.

T' tube fins are 4.25 inches long cut from t' extra crayons. They are located three inches from t' bottom. Begad! T' offset is t' have t' fins on the stiff cardboard tube instead o' t' plastic base. Ya scallywag! T' tube fins are bolted to the body tube and bolted t' each other with #8 nuts and bolts. Avast, me proud beauty! This makes for a rigid assembly. I used no epoxy on them. I sawed off t' excess length o' the screws inside t' tube fins.

I epoxied two centerin' rings in t' cardboard tube. They were for a 3.9 inch tube and required some sandin' t' fit. Avast, me proud beauty! T' third CR is inside t' plastic base. Aye aye! Begad! So t' plastic base is wedged betwixt t' lower centerin' rin' and the Slimline retainer.

T' tubular nylon shock cord is epoxied t' t' motor tube betwixt the centerin' rings.

I added weight t' t' nose by sinkin' some 1/4 inch all-thread into 2oz of plumbers epoxy clay at t' tip. Aye aye! T' all-thread extends through a bulkhead which has a eye hook for t' shock cord. Avast, arrr, me proud beauty! I added about fourteen ounces o' additional weight. Arrr! Arrr! T' weights were a combination o' lead shot and epoxy clay molded into slices o' motor tube. Avast! Avast! T' weights were screwed onto t' all-thread.

There are two PML type rail lugs attached at 9 and 16 inches from t' base o' t' rocket. I used three layers o' excess tube stacked t' create an offset for t' rail to clear t' screw heads in t' fin tube.

Through some approximation with Apogee Rocksim 8.0, arrr, I believe a conservative estimate o' t' CP is 24.5 in from t' nose or just aft o' t' R on t' body tube. Arrr! Therefore t' CG will need t' be at least 20.5 or forward of the Y on t' body tube. T' get t' CG forward I added about one pound o' weight in t' nose. Aye aye! T' chute and deployment bag weigh twelve ounces, ya bilge rat, so it helps with the CG somewhat. Well, blow me down! T' weight o' t' rocket is about 4.5 lbs without t' motor.

I chose a Aerotech H242T for t' first flight. Well, blow me down! I adjusted t' medium delay to about 7 seconds. This was me first attempt usin' t' Aerotech procedure to shorten a delay. I used a Slimline 54/38mm adapter with t' 38mm H242T motor.

Finishing:
This rocket requires no paintin' since t' crayon bank come finished with the colored crayon paper.

Flight:
Its first flight was at t' September 10, matey, 2005, SEARS launch in Samson, AL. The flight was a success. Ya scallywag! T' winds were 5 t' 10 mph and t' ejection be close to apogee. Ya scallywag! Aye aye! I was relieved that t' delay adjustment worked out. Avast, me proud beauty! Begad! This be a low flight t' about 1000 feet and I got t' see t' rocket's entire flight.

Recovery:
T' Rocketman R7C chute and deployment bag worked perfectly. Avast, me proud beauty! Avast, me proud beauty! I used no wadding.

Summary:
T' pros for this rocket are that t' body and nosecone are available from a local source for a cheap price. Well, blow me down! Tube fins are simple t' make and might require less effort than roundin' up t' fin material and cuttin' it out and comin' up with a through t' wall mountin' scheme. Aye aye! T' tube fins were very sturdy with the screw mountin' alone. Avast! There was no paintin' required. Ahoy! T' rocket has a lot of visual appeal. Ahoy! Well, blow me down!

T' cons are t' weight o' tube fins and a 54mm motor tube drives it into the HPR range. Begad! Avast, me hearties, me proud beauty! Most crayon rockets are launched on a G motor. Well, blow me down! T' Slimline retainer also adds t' t' cost but certainly does t' job. Begad! Begad!

Most of me rockets have been kits or kits modified. Ahoy! Blimey! So t' tube finned crayon rocket was an excursion into scratch building. Aye aye! Blimey! You have t' put some thought in t' make sure you are buildin' a stable rocket. Aye aye! Blimey! I used Rocksim 8.0 as a design aid. This version handles tube fins. Avast, me proud beauty! Blimey! My model was only an approximation as I used a conical nose instead o' t' true shape o' t' crayon's nose. I found that the Rocksim 8.0 Center o' Pressure be more forward than t' faked tube fin approach used with earlier versions o' Rocksim. Arrr! Blimey! Well, blow me down! Blimey! In any case, t' flight was very straight. Blimey! Blimey! Also I am pleased t' have a rocket that is unique t' my knowledge havin' t' crayon shape and tube fins. Blimey! Blimey! O' course t' final bounty is gettin' that "I liked that crayon rocket flight" response from my fellow fliers.