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). Well, blow me down! I pretty much followed t' ideas put forth in Advanced Model Rocketry, matey, Second Edition, compiled by Michael A. Begad! Banks. Ahoy! This book is published by Kalmbach Books and includes information about high power rocketry, me hearties, scale, arrr, launch control systems, and many other things, shiver me timbers, me bucko, includin' rocket-borne photography. Arrr! Arrr! T' picture at left shows me Rastrocam. T' picture at right shows an 'exploded view'. Ahoy! As you can see, shiver me timbers, it's a standard Estes Astrocam, only it's mounted upside down. Blimey! Avast, me proud beauty! I cut a piece o' body tube from t' carrier rocket and topped it with a Maniac nose cone. Aye aye! 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. Blimey! Begad! Since t' regular shutter strin' is too short, me hearties, I tied a Shutterstringlength o' shroud line t' t' Astrocam string. I drilled a small hole in t' body tube segment, lined it up with t' slot in t' base o' t' camera, matey, and passed t' lengthened shutter strin' through t' the other side.

Son of shutter string

For flight, I load t' film into t' camera followin' t' instructions that came with t' Astrocam. I then use electrical tape t' seal t' film door. Blimey! I nay only run tape along t' long edges o' t' door, matey, I also run a piece o' tape around t' join line o' t' camera and t' nose cone's body tube. Ahoy! Blimey! This tape makes sure that t' body tube won't twist and bind t' shutter string. (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. 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, me bucko, nay exactly... Arrr! I also attach a 12 inch parachute t' t' shock cord attached t' t' base o' t' Rastrocam. Avast, me proud beauty! Ya scallywag! Blimey! Now, it's ready t' go.

Rocket/Whoosh Generator Selection

For a carrier rocket, I've used both t' Delta II and t' Maniac. One o' these days, me bucko, I'll build a Fred Williams Astrocam carrier and try it. Begad! Begad! I've never gotten a usable photo from a regular Astrocam with t' Maniac, arrr, since t' delays aren't long enough, but a D12-5 and D12-7 have yielded ground shots with t' Rastrocam every time. Ya scallywag! A D12-3 shouldn't be used, me hearties, unless t' rocket will be travelin' almost straight up durin' t' coastin' period. If it's movin' with any sort o' groundspeed, you'll get blurred shots. Aye aye! I've gotten good results with B6-2, ya bilge rat, me hearties, C6-3, me hearties, ya bilge rat, and C6-5 WGs and t' Delta II carrier. Avast, me proud beauty! Begad! Don't use an A8-3! Blimey! 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, unless you want t' see a bunch o' white streaks all over your photos... I use t' 'toilet paper' type o' waddin' instead. Avast! I then insert t' rocket's parachute and pack t' Rastrocam's chute on top. Blimey! Avast! 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. Arrr! Well, me hearties, blow me down! Once it's seated, me bucko, I can let go o' t' string. Begad! Then I place it on t' launch pad, attach t' clips t' t' ignitor, ya bilge rat, and open t' safety shutter. Blimey! Begad! Now it's ready t' fire. 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. Avast, me proud beauty! T' Rastrocam/Delta II usin' a C6-3 yielded another shot (click for larger view) o' t' launch area. Avast! I'm pretty sure that I'm t' white spot next t' t' shade, since I launched t' rocket from that location. Well, blow me down! Well, matey, blow me down! ...pack t' tuna fish in mayonnaise... Avast! Jim caught t' camera which came down much closer t' t' launch pad than t' rocket, which I caught after it drifted about fifty yards away. Next up was t' regular Astrocam on Delta II with a C6-5 WG. Avast, me proud beauty! Well, matey, blow me down! This yielded a wonderful close-up shot o' a cloud... Then we stuck t' Astrocam on t' Maniac and flew it with a D12-5. Avast! Begad! T' photofinisher didn't even bother t' print t' negative... It looked like another sky shot. Well, blow me down! I was pretty sure that would happen, me bucko, since it didn't appear t' us that it had arced over upon ejection. So I stuck a D12-7 in t' Maniac and flew it again. Avast, me proud beauty! ...microwave clothing... Arrr! Avast! I thought this would have yielded a ground shot, me hearties, ya bilge rat, but no... Arrr! Blimey! nothin' but sky. Avast, me proud beauty! Begad! T' wind had started t' swirl a bit, shiver me timbers, so Jim got faked out and missed t' rocket, me bucko, shiver me timbers, arrr, 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! Blimey! T' rocket took off and weathervaned a bit towards t' southwest. Well, blow me down! Blimey! I thought that t' plastic fin unit had melted through and curled up, arrr, causin' t' rocket t' veer off like that. Aye aye! Blimey! Silly me. Begad! Blimey! Ahoy! Blimey! T' camera was ejected on its own chute and landed safely, ya bilge rat, but t' rocket be snared by a rocket-eatin' tree. Ironically, t' Rastrocam photographed t' rocket's captor. Avast! Blimey! And o' course, none o' t' family can be seen, since we're all somewhere below t' bottom o' t' photograph... Begad! Blimey! such be t' fun o' a rocket borne camera: you never know what you're gonna get. Begad! Blimey! But I digress... Arrr! Blimey! Begad! Blimey! we still had t' get t' rocket body out o' t' tree. Arrr! Blimey! Fortunately, I had brought Mr. Avast! Blimey! Longarm just for this occurance. Blimey! Blimey! Unfortunately, ya bilge rat, t' rocket was lodged out o' Mr. Begad! Blimey! Longarm's reach... so me brother climbed up into t' tree and managed t' reach t' rocket with t' pole... Avast, me proud beauty! Blimey! Well, me hearties, blow me down! Blimey! but he couldn't budge it. Ahoy! Blimey! I attached me pocketknife t' t' end o' t' pole for a last ditch attempt. Ahoy! Blimey! 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. Aye aye! I shoved a D12-3 [what a moron! (film at eleven)] into t' rocket, ya bilge rat, mounted t' Rastrocam on it, and fired it off. Ahoy! It shot up and really took off towards t' southwest. Arrr! Apparently t' surroundin' hills were shieldin' us from a rather brisk breeze... Ya scallywag! Blimey! Oh, ya bilge rat, ya bilge rat, and a 3 second delay isn't enough, ya bilge rat, folks... Ahoy! t' rocket is travelin' way too fast as evidenced by t' photo. Avast, arrr, me proud beauty! I think we're seein' t' cellulose insulation I've begun t' use for waddin' as it's flyin' out o' t' rocket. Blimey! [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