Scratch Liddle V2 Original Design / Scratch Built

Scratch - Liddle V2 {Scratch}

Contributed by Sean R Liddle

Manufacturer: Scratch
(Contributed - by Sean R. Avast, me proud beauty! Liddle - 12/01/01)

Rocket Pic Brief:
Scratch designed and built V2 usin' LOC nosecones and Estes body tube.

Construction:
One Estes BT-80 body tube, arrr, four fins (1/8" plywood), plywood centering rin' (1), me hearties, LOC MM2 motor mount kit, shiver me timbers, arrr, shiver me timbers, 1 inch elastic shock cord and 1/8 inch nylon cord shock cord mount, ya bilge rat, shiver me timbers, small eyebolts for mountin' cord, matey, ya bilge rat, arrr, two LOC 2.56 nosecones for nose and boattail. Well, blow me down! Aye aye!

After printin' out patterns for fins from Rocksim (see Rocksim file link button above), me bucko, fins were cut and sanded. Avast, me proud beauty! Well, blow me down! Nosecone t' be used for boattail was cut by removin' tip until internal measurement be found t' be slightly larger than outer diameter o' 29mm motor mount tube. Arrr! Blimey! Base o' cone was then cut leaving about 1.5 inches o' shoulder remainin' t' couple boattail t' BT-80 tubing. Aye aye! The removed portion was retained for construction o' a piston.

T' MMA2 motor mount adapter was constructed in such a way as t' have the inner 29mm tube past t' bottom centerin' rin' o' t' outer tube by only 1 cm. This stepped area allows for injection o' epoxy around t' MM tube and resultin' with a firmer connection betwixt t' MMA and t' boattail at the base. Epoxy t' large centerin' rin' onto t' upper end o' t' motor mount tube then t' MMA assembly into t' boattail. Blimey! Then eyeball it center and allow it to dry. Avast! Begad! Blimey! When dry, drill a small hole into t' upper centerin' rin' about 1 cm from the edge and epoxy in a small epoxy in t' hole. Ahoy! Blimey! Insert and epoxy t' centering rin' and t' shoulder o' t' boattail into t' BT-80 . Begad! Ya scallywag! Blimey! Allow t' dry overnight. Mark t' slots onto t' boattail then cut t' tab holes. Begad! Blimey! I used a very sharp Exacto blade after a bad experience with me Dremel Tool.

I then constructed a piston usin' t' piece o' t' nosecone I cut off to make t' boattail. Arrr! I won't describe it here as I have discovered that t' lack of space betwixt it and t' upper centerin' rin' caused problems. Ahoy! Avast, matey, me proud beauty! It is a good idea for larger rockets. I am sure (feel free t' try it), arrr, shiver me timbers, but I will be removin' it from me personal V2. Avast, me proud beauty! Epoxy t' fins in place and allow t' dry 2 hours. Aye aye! Insert 75-100 grams o' plasticine into t' second nosecone (the real one) pack it in place by use o' a chopstick (my tool o' choice) or other implement. Begad! Choose a chute, shiver me timbers, matey, construct it as needed. I made one out o' ripstop nylon, usin' hemmin' tape t' seal t' edges and small grommets t' act as shroud line holes. Well, blow me down! Tie t' nylon shock cord mount t' t' eyebolt by makin' a loop and shovin' it through t' eyelet with a pencil. Blimey! Sure you could tie one on before you glued t' boattail t' t' body tube, matey, but that's nay adventurous is it? Tie 1 meter o' elastic from t' nosecone t' t' shock cord mount. Ya scallywag! Tie other t' the nosecone. Add t' chute and you are good t' go.

Rocket PicFlight:
As I mentioned, t' piston was a BAAAAAD idea. Ya scallywag! First flight be an F25-4. Three tries t' ignite and when it did a small cloud o' flame popped out o' t' engine nozzle and crept up t' fins, 1/2 a second later off she went, ZOOOOOOOM.. High and straight! Then t' ejection went. Avast, me bucko, me proud beauty! T' nosecone, ya bilge rat, piston and parachute landed 500 meters downrange in a horse field. Ya scallywag! T' body fell 100 meters plus for a safe landin' in a garden! Examination showed that even though I added two sheets of Estes waddin' t' t' motor mount tube ahead o' t' engine, t' elastic still burned enough t' fail. Arrr! Next launch in two weeks with no piston!!

Flew very well. Ahoy! Arrr! Very very excitin' flight! Will remove piston soon.

Next flight is an Aerotech E motor.

UPDATE:
Three weeks after t' maiden flight on me V2, I have made a small modification, me bucko, and subsequently two more flights.

Modification: Removal o' piston, addition o' 1/4" swivel betwixt nylon shock cord mount and shock cord.

Flight one: 01/12/02. 10:40 am, arrr, Kingston, Ontario. Ya scallywag! Winds: 20km/hour, slightly overcast skies, 7 degrees Celsius. Engine: Aerotech E30-7T

Nice straight off t' pad launch. Avast! Slight cockin' into t' wind. Ejection a few seconds after apogee. Avast, me proud beauty! Fast decent 250 meters downwind from t' pad. Aye aye! Avast! Slight damage t' t' fillets (most o' which was simply damage nay repaired from first flight). Nice flight and recovery.

Flight two: 01/12/02. Well, blow me down! Blimey! 11:20 am, arrr, Kingston, arrr, Ontario. Winds: 20km/hour, me hearties, slightly overcast skies, matey, 7 degrees Celsius. Engine: Aerotech F50-9W

V2 flew off t' pad with a roar. Okay, me hearties, more o' a loud whoosh. Well, blow me down! Cocked, matey, shiver me timbers, as expected, arrr, into t' wind about 15 degrees from t' pad. Arrr! Ya scallywag! Climbed approx. Begad! 2500 feet (accordin' t' Rocksim). Chute deployed a few seconds after apogee and rocket hung. And hung and hung. Avast, me bucko, me proud beauty! Then started t' ever so slowly head downwind. Arrr! Blimey! It passed over t' field, arrr, t' line o' trees, t' swamp, a large open field and just before landin' in t' next largest field, found t' top few branches o' a 20 foot tall tree which be covered in thorns. Blimey! Aye aye! T' only tree in t' area. Blimey! Apparently thar was an upper level wind we were unaware of. Avast! After a large degree o' bloodshed, shiver me timbers, shiver me timbers, torn clothin' and language best used in an R rated movie, me hearties, t' tree was climbed and t' V2 be recovered intact. Ya scallywag!

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