APStrocam

The Estes Astrocam is OK, but only taking one pic per flight is boring. I've wanted to build something better for a while, but didn't want to shell out loads on a camera, just to trash it on the first flight. So the criteria for the camera were, size, weight, cost and it had to have auto wind on. The Chinon AP 300S meets most of these criteria. It cost �20 ( + �5 for the battery!), has a motorised wind on, and is fairly small and lightweight.

Plans & Materials

Since I had started with a tight budget, I thought I might as well carry on that way. A 55mm diameter postal tube served for both the camera housing and the rocket body. The fins are from 1.5mm thick balsa. The nose cone is recycled from the MkVI and the camera mounting made from various bits of scrap balsa. Engine mounts were cardboard cores ( which are exactly 24mm inside diameter) from rolls of cling film.

From left to right:

• Here's the camera still partially in it's case. You can see the tube for the housing with the slot ready to take the camera. You can also see the gouges on the nose cone from it's previous flight!
• A quick sketch.

Mounting the camera

The original idea was to fit the camera inside the tube with slots for access to the film and battery opening. The camera didn't quite fit inside the tube even with the case off, so the tube is slotted on both sides. The side of the camera with the openings is mounted flush with the tube, and the camera protruded through the other side. Holes have been cut for the lens and for access to the switch panel. The switch panel consists of an 8 way DIL switch mounted in a piece of scrap balsa. The camera is mounted on its side, which leads to the perculiar orientation of the photos. The camera is held in place by liberal application of epoxy. This almost led to disaster after I glued the film door shut! Fortunately I realised before it had cured and so I was able to 'exercise' the hinge until it set. The nose cone is permanently attached. At the rear end of the camera enclosure there is a bulkhead with a hole for access to the film release mechanism. A tube joiner is permanently attached to the enclosure, and slips inside the rocket body. The shock cord is tied to an eye hook epoxied into a balsa block. A cardboard shroud is glued over the external camera parts. This also covers the microswitch which is epoxied to the outside of the rear of the enclosure. The completed camera enclosure weighs about 160g.

From left to right:

• The top of the camera. This is covered by the cardboard shroud on the finished rocket.
• A view inside from the fore ( nose cone) end.
• View from the front showing cutout for lens.

The finished APStrocam / MkVII

After the red / yellow diversion of the MkVI, I've gone back to my traditional fluorescent orange, but with black trim, for the APStrocam ( actually the MkVII). The text is hand painted on. The technique I use is to reverse print what I want onto ordinary paper, then trace over the outline with a soft pencil. The printout is then taped to the tube / fin and the outline transfered by rubbing over it with a harder pencil. Then I have a large whiskey ( to steady my shaking hand) and fill it in with paint. I'm fairly pleased with the outcome, although it is underpowered on two D12 motors. I really need to get the appropriate certification in place to be able to buy and store composite propellant motors. Next step, two Aerotech E motors!

From left to right:

• Ready.
• 5, 4, 3, 2, 1...
• Launch!

• Recovery. That's the home made hemisperical 'chute that never got used on the MkVI.

How it works

The unmodified camera has those little rubber buttons for taking pics, and sliders operating microswitches to select the picture size and turn it on. Wire wrap wire soldered to the connections of these switches feed through to the switch panel. The switch panel is epoxied to the camera for strength. The switches on the panel have the following functions:

• 1: Power.
• 2: Print aspect ratio.
• 3: Print aspect ratio.
• 4: Fill-in flash ( not actually useful).
• 5: Mid roll rewind.
• 6: Self timer / auto shutter.
• 7: Battery check / shutter release.
• 8: Shutter release.

• View into the control panel.

The camera has several modes of operation:

• 1: To take a single shot 1 must be on then 7 & 8.
• 2: To take a single shot after 10 seconds, turn on 1, turn on 6 and then release it. Shot is taken after 10 seconds.
• 3: To take a continous sequence of shots, turn on 1, then turn on 6, 7 & 8 in that order. Camera takes all shots left on film, then rewinds.

Results

Here are the results, in-flight pictures...

• Flight 1: 3rd April 1999, Baildon Moor. Flown on 2 x Estes D12-5.
• Flight 2: 3rd April 1999, Baildon Moor. Flown on 2 x Estes D12-5.
• Flight 3: Sometime between April and June, Baildon Moor. Flown on 2 x Estes D12-5. Flat battery, so no pics.
• Flight 4: 17th July 1999, Baildon Moor. Flown on 2 x Estes D12-5.
• Flight 5: 3rd October 1999, Pete's Farm. Flown on 2 x Aerotech E15.

So, that's it. The rocket is a write off. The nose cone will fly again, again ( it was second hand already), but I'm not sure about the payload section. The camera seemed OK, after all the film was rewound, however when I fitted a new film, it failed to wind on. I could take it apart to see what's up, but the camera is pretty much built into the payload tubing. Even if I can get it out, it will be pretty hard to build into another rocket.

I have seen a similar Chinon camera, but with 35mm film. That will be cheaper film processing. If it has auto wind-on, I'm getting it!

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