Scratch Liddle V2 Original Design / Scratch Built

Scratch - Liddle V2 {Scratch}

Contributed by Sean R Liddle

Manufacturer: Scratch
(Contributed - by Sean R. Blimey! 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, ya bilge rat, arrr, four fins (1/8" plywood), plywood centering rin' (1), arrr, LOC MM2 motor mount kit, me bucko, me hearties, 1 inch elastic shock cord and 1/8 inch nylon cord shock cord mount, me hearties, small eyebolts for mountin' cord, two LOC 2.56 nosecones for nose and boattail. Well, blow me down! Arrr!

After printin' out patterns for fins from Rocksim (see Rocksim file link button above), me bucko, arrr, fins were cut and sanded. Blimey! Blimey! 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! Blimey! Blimey! Base o' cone was then cut leaving about 1.5 inches o' shoulder remainin' t' couple boattail t' BT-80 tubing. Well, blow me down! Blimey! Blimey! Blimey! Blimey! Blimey! The removed portion was retained for construction o' a piston. Blimey! Blimey! Blimey! Blimey!

T' MMA2 motor mount adapter be 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. Arrr! Aye aye! Epoxy t' large centerin' rin' onto t' upper end o' t' motor mount tube then t' MMA assembly into t' boattail. Avast, me proud beauty! Ya scallywag! Then eyeball it center and allow it to dry. When dry, matey, 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! Insert and epoxy t' centering rin' and t' shoulder o' t' boattail into t' BT-80 . Begad! Avast! Allow t' dry overnight. Mark t' slots onto t' boattail then cut t' tab holes. Well, blow me down! 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! Blimey! I won't describe it here as I have discovered that t' lack of space betwixt it and t' upper centerin' rin' caused problems. It is a good idea for larger rockets. Begad! Blimey! Ya scallywag! Blimey! I am sure (feel free t' try it), shiver me timbers, me bucko, but I will be removin' it from me personal V2. Well, blow me down! Blimey! Epoxy t' fins in place and allow t' dry 2 hours. Ahoy! Blimey! 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. Ya scallywag! Blimey! Choose a chute, arrr, construct it as needed. I made one out o' ripstop nylon, shiver me timbers, me bucko, usin' hemmin' tape t' seal t' edges and small grommets t' act as shroud line holes. Well, blow me down! Blimey! Aye aye! Blimey! Tie t' nylon shock cord mount t' t' eyebolt by makin' a loop and shovin' it through t' eyelet with a pencil. Sure you could tie one on before you glued t' boattail t' t' body tube, shiver me timbers, me hearties, but that's nay adventurous is it? Tie 1 meter o' elastic from t' nosecone t' t' shock cord mount. Tie other t' the nosecone. Avast, me proud beauty! Blimey! Add t' chute and you are good t' go.

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

Flew very well. Avast! 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, 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. Well, blow me down! Aye aye! 10:40 am, Kingston, Ontario. Winds: 20km/hour, arrr, slightly overcast skies, 7 degrees Celsius. Engine: Aerotech E30-7T

Nice straight off t' pad launch. Avast, me proud beauty! Begad! Slight cockin' into t' wind. Blimey! Ya scallywag! Ejection a few seconds after apogee. Ahoy! Fast decent 250 meters downwind from t' pad. Blimey! Slight damage t' t' fillets (most o' which be simply damage nay repaired from first flight). Well, blow me down! Ya scallywag! Nice flight and recovery.

Flight two: 01/12/02. 11:20 am, ya bilge rat, Kingston, Ontario. Winds: 20km/hour, slightly overcast skies, ya bilge rat, 7 degrees Celsius. Engine: Aerotech F50-9W

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

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