Scratch RastroCam Original Design / Scratch Built

Scratch - RastroCam {Scratch}

Contributed by Sven Knudson

Manufacturer: Scratch

Note: click on t' mini-photos or hypertext links t' get t' full sized photo with caption.

RastrocamExploded view Several people have asked me how I built me Rastrocam (rearward lookin' Astrocam). Avast! I pretty much followed t' ideas put forth in Advanced Model Rocketry, ya bilge rat, Second Edition, compiled by Michael A. Banks. Well, blow me down! Blimey! Ya scallywag! Blimey! This book is published by Kalmbach Books and includes information about high power rocketry, arrr, scale, ya bilge rat, me bucko, launch control systems, and many other things, includin' rocket-borne photography. T' picture at left shows me Rastrocam. Avast, me proud beauty! Blimey! Blimey! Blimey! T' picture at right shows an 'exploded view'. Aye aye! As you can see, it's a standard Estes Astrocam, shiver me timbers, only it's mounted upside down. Ahoy! I cut a piece o' body tube from t' carrier rocket and topped it with a Maniac nose cone. Begad! Blimey! A length o' elastic shock cord ensures it will stay with t' camera. I glued a baseJT-55 stage coupler t' t' nose o' t' Astrocam t' allow it t' fit into t' rocket's body tube and cut a notch in t' coupler t' serve as t' shutter strin' holder. Ya scallywag! Since t' regular shutter strin' is too short, ya bilge rat, I tied a Shutterstringlength o' shroud line t' t' Astrocam string. Begad! I drilled a small hole in t' body tube segment, lined it up with t' slot in t' base o' t' camera, and passed t' lengthened shutter strin' through t' the other side.

Son of shutter string

For flight, me hearties, I load t' film into t' camera followin' t' instructions that came with t' Astrocam. Aye aye! I then use electrical tape t' seal t' film door. Well, blow me down! I nay only run tape along t' long edges o' t' door, arrr, I also run a piece o' tape around t' join line o' t' camera and t' nose cone's body tube. Begad! Avast, me proud beauty! This tape makes sure that t' body tube won't twist and bind t' shutter string. Aye aye! Arrr! (I suppose you could glue t' body tube t' t' camera, but then it wouldn't be easy t' replace if it gets banged up.) Make sure t' strin' can move freely! A length o' tape around t' bottom completes t' encapsulement o' t' camera. Well, blow me down! Blimey! I attach t' Maniac nose cone t' t' shock cord and put it on top o' its body tube t' complete t' flight configuration. Well, blow me down! Aye aye! Well, nay exactly... I also attach a 12 inch parachute t' t' shock cord attached t' t' base o' t' Rastrocam. Ya scallywag! Begad! Now, it's ready t' go.

Rocket/Whoosh Generator Selection

For a carrier rocket, I've used both t' Delta II and t' Maniac. Ya scallywag! One o' these days, ya bilge rat, ya bilge rat, arrr, I'll build a Fred Williams Astrocam carrier and try it. I've never gotten a usable photo from a regular Astrocam with t' Maniac, since t' delays aren't long enough, but a D12-5 and D12-7 have yielded ground shots with t' Rastrocam every time. Avast! A D12-3 shouldn't be used, unless t' rocket will be travelin' almost straight up durin' t' coastin' period. Avast! Aye aye! If it's movin' with any sort o' groundspeed, you'll get blurred shots. Well, blow me down! I've gotten good results with B6-2, C6-3, matey, and C6-5 WGs and t' Delta II carrier. Don't use an A8-3! You can throw t' rocket higher than it'll go on that motor.

Flight Prep

I don't recommend usin' cellulose insulation as waddin' with t' Rastrocam, ya bilge rat, unless you want t' see a bunch o' white streaks all over your photos... I use t' 'toilet paper' type o' waddin' instead. I then insert t' rocket's parachute and pack t' Rastrocam's chute on top. Aye aye! Then, makin' sure that t' safety shutter is closed, I cock t' camera by pullin' t' strin' through t' notches in t' stage coupler and hold it tight while placin' t' Rastrocam on t' rocket. Well, blow me down! Once it's seated, I can let go o' t' string. Ya scallywag! Then I place it on t' launch pad, ya bilge rat, attach t' clips t' t' ignitor, and open t' safety shutter. Aye aye! Ahoy! Now it's ready t' fire. Ya scallywag! Avast, me proud beauty! Say "cheese!"


Rastrocam launch reports

Launch report: 8/27/95:

Click for Bigger PictureThen we went into a strin' o' camera flights. Well, ya bilge rat, blow me down! T' Rastrocam/Delta II usin' a C6-3 yielded another shot (click for larger view) o' t' launch area. Ya scallywag! I'm pretty sure that I'm t' white spot next t' t' shade, since I launched t' rocket from that location. Avast, me proud beauty! Blimey! ...pack t' tuna fish in mayonnaise... Begad! Jim caught t' camera which came down much closer t' t' launch pad than t' rocket, me bucko, which I caught after it drifted about fifty yards away. Next up be t' regular Astrocam on Delta II with a C6-5 WG. This yielded a wonderful close-up shot o' a cloud... Ahoy! Then we stuck t' Astrocam on t' Maniac and flew it with a D12-5. Blimey! Begad! T' photofinisher didn't even bother t' print t' negative... It looked like another sky shot. Begad! Arrr! I be pretty sure that would happen, since it didn't appear t' us that it had arced over upon ejection. Ahoy! So I stuck a D12-7 in t' Maniac and flew it again. ...microwave clothing... Avast, me proud beauty! Blimey! I thought this would have yielded a ground shot, shiver me timbers, arrr, but no... nothin' but sky. Aye aye! T' wind had started t' swirl a bit, so Jim got faked out and missed t' rocket, me bucko, but I managed t' catch t' camera.

Launch report: 4/7/96:

Click for Larger ViewI decided I would try for a different type o' Easter family protrait by flyin' t' Rastrocam on a Delta-II with a B6-2. Avast! T' rocket took off and weathervaned a bit towards t' southwest. I thought that t' plastic fin unit had melted through and curled up, arrr, causin' t' rocket t' veer off like that. Aye aye! Begad! Silly me. Avast! Avast! T' camera was ejected on its own chute and landed safely, arrr, but t' rocket be snared by a rocket-eatin' tree. Blimey! Ironically, shiver me timbers, t' Rastrocam photographed t' rocket's captor. Well, blow me down! And o' course, shiver me timbers, none o' t' family can be seen, matey, since we're all somewhere below t' bottom o' t' photograph... Blimey! such be t' fun o' a rocket borne camera: you never know what you're gonna get. Begad! But I digress... Well, blow me down! Ya scallywag! we still had t' get t' rocket body out o' t' tree. Well, blow me down! Avast! Fortunately, me bucko, I had brought Mr. Well, blow me down! Well, blow me down! Longarm just for this occurance. Ya scallywag! Unfortunately, t' rocket was lodged out o' Mr. Longarm's reach... so me brother climbed up into t' tree and managed t' reach t' rocket with t' pole... Ahoy! but he couldn't budge it. I attached me pocketknife t' t' end o' t' pole for a last ditch attempt. My brother finally managed t' sever t' shock cord and t' rocket dropped t' t' ground.

We rested a bit, then I wanted t' try t' Rastrocam on a Maniac. Avast, me proud beauty! Aye aye! I shoved a D12-3 [what a moron! (film at eleven)] into t' rocket, mounted t' Rastrocam on it, arrr, and fired it off. Well, blow me down! Begad! It shot up and really took off towards t' southwest. Ahoy! Apparently t' surroundin' hills were shieldin' us from a rather brisk breeze... Ya scallywag! Oh, and a 3 second delay isn't enough, folks... t' rocket is travelin' way too fast as evidenced by t' photo. Ya scallywag! I think we're seein' t' cellulose insulation I've begun t' use for waddin' as it's flyin' out o' t' rocket. Begad! [Note t' self: Maybe it's nay such a good idea t' use this type o' waddin' when flyin' t' Rastrocam.] And I'm pretty sure that t' horizon be t' bright area at t' upper right o' t' photo.

comment Post a Comment