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, four fins (1/8" plywood), plywood centering rin' (1), LOC MM2 motor mount kit, arrr, 1 inch elastic shock cord and 1/8 inch nylon cord shock cord mount, small eyebolts for mountin' cord, ya bilge rat, arrr, two LOC 2.56 nosecones for nose and boattail. Begad!

After printin' out patterns for fins from Rocksim (see Rocksim file link button above), matey, fins were cut and sanded. Nosecone t' be used for boattail was cut by removin' tip until internal measurement was found t' be slightly larger than outer diameter o' 29mm motor mount tube. Begad! Base o' cone was then cut leaving about 1.5 inches o' shoulder remainin' t' couple boattail t' BT-80 tubing. Avast! 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. Ya scallywag! Epoxy t' large centerin' rin' onto t' upper end o' t' motor mount tube then t' MMA assembly into t' boattail. Then eyeball it center and allow it to dry. 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. Begad! Insert and epoxy t' centering rin' and t' shoulder o' t' boattail into t' BT-80 . Blimey! Begad! Allow t' dry overnight. Mark t' slots onto t' boattail then cut t' tab holes. Avast, me proud beauty! Avast, matey, me proud beauty! 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. Aye aye! I won't describe it here as I have discovered that t' lack of space betwixt it and t' upper centerin' rin' caused problems. Avast, me proud beauty! It is a good idea for larger rockets. Blimey! Begad! I am sure (feel free t' try it), but I will be removin' it from me personal V2. Ahoy! Epoxy t' fins in place and allow t' dry 2 hours. Arrr! 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, arrr, construct it as needed. Well, blow me down! I made one out o' ripstop nylon, matey, usin' hemmin' tape t' seal t' edges and small grommets t' act as shroud line holes. Blimey! Begad! Tie t' nylon shock cord mount t' t' eyebolt by makin' a loop and shovin' it through t' eyelet with a pencil. Begad! Sure you could tie one on before you glued t' boattail t' t' body tube, shiver me timbers, arrr, but that's nay adventurous is it? Tie 1 meter o' elastic from t' nosecone t' t' shock cord mount. Arrr! Avast, me proud beauty! Tie other t' the nosecone. Avast, me proud beauty! Add t' chute and you are good t' go.

Rocket PicFlight:
As I mentioned, t' piston be a BAAAAAD idea. Arrr! Blimey! Begad! Blimey! First flight be an F25-4. Begad! 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, me bucko, 1/2 a second later off she went, me hearties, ZOOOOOOOM.. Avast! Blimey! High and straight! Blimey! Then t' ejection went. Blimey! Blimey! T' nosecone, piston and parachute landed 500 meters downrange in a horse field. Ahoy! Blimey! Aye aye! 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, matey, ya bilge rat, t' elastic still burned enough t' fail. Blimey! Blimey! Ahoy! Blimey! Next launch in two weeks with no piston!!

Flew very well. 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, arrr, I have made a small modification, me hearties, and subsequently two more flights.

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

Flight one: 01/12/02. Avast! Well, ya bilge rat, blow me down! 10:40 am, shiver me timbers, Kingston, me bucko, Ontario. Ya scallywag! Winds: 20km/hour, slightly overcast skies, shiver me timbers, arrr, arrr, 7 degrees Celsius. Engine: Aerotech E30-7T

Nice straight off t' pad launch. Begad! Begad! Slight cockin' into t' wind. Ahoy! Well, blow me down! Ejection a few seconds after apogee. Begad! Fast decent 250 meters downwind from t' pad. 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. 11:20 am, shiver me timbers, Kingston, arrr, arrr, Ontario. Winds: 20km/hour, slightly overcast skies, 7 degrees Celsius. Engine: Aerotech F50-9W

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

comment Post a Comment