View Single Post
  #2  
Old 10-14-2008, 05:04 AM
Bill's Avatar
Bill Bill is offline
I do not like Facebook
 
Join Date: Sep 2008
Location: North Tejas
Posts: 3,087
Default

These are my experiences. I joined the team a week after they had already begun work. We were tasked to build ten of the models. Our policy was to match the SA-205 as much as possible and not preclude keeping the model flyable.
  1. Basic model rocket building techniques - We had no concerns in this area as we had all built many rockets.
  2. Research - Unfortunately, we did not thoroughly research the SA-205 before construction, so we had to redo a few things for accuracy and a few other things were left uncorrected.

    The Mighty Saturns DVD set proved to be valuable as an entire disc was filled with launch footage of Apollo 7 including many closeup views from tower and umbilical arm cameras.
  3. Building around a reference line - This was a continuing challenge as we had to repeatedly refer to the instructions and we did not get it right every time. In fact, we got it wrong at some critical times.
  4. Building up hollow fins - One of the team members was good at this and volunteered to build all of them. I'll leave it up to him to write about his experiences.
  5. Resin casting - We chose not to do this for the fins. Perhaps we could have made and replicated an accurate retrorocket housing if we had known early in the build process.
  6. Forming and gluing paper shrouds - We had a tough time with the tank fairing shrouds. We ended up adding pointed tips to the spacer strips (A) similar to the fairing supports (B) in order to provide a place to glue the narrow parts of the shroud then wound up cutting apart some of the shrouds and gluing them in place separately. Even so, we had to do a great deal of filling after attaching wrap #2 so that the fairing blended nicely.

    As for the LEM shroud, we cut off the overlap area and used it to back the butt joint between the edges of the shroud. We spent way too much effort filling the joint between the lower edge of the shround and the second stage tube not realizing at the time that a color boundary will help to hide it.
  7. Fabricating parts with launch lug and cardstock - One of the team members did a good job on the discharge tubes. We opted to make the retrorocket housings out of strip balsa as nobody wanted to do it as the kit instructions directed.
  8. Fabricating balsa parts - Our retrorocket housings were originally pointed at both ends as suggested by the kit instructions until the Apollo 7 footage clearly showed the aft ends to be square. So we cut ours in half and extended them with more strip stock, giving us many spares.

    Using a drill instead of a dowel did a much better job on the nozzles of the vector control jet housings.
  9. Applying tube wraps - This is where I contributed my share of mistakes to the project. I got confused and glued two of the wrap #4 upside down. Fortunately, the texture of the wraps does not really show on the finished model and many of the flat spots still lined up with detail parts.

    The techniques for applying the wraps varied among team members. Mine was to apply Elmers Glue-All to the tube, spread it out with a finger and after cleaning my hands, started the wrap by carefully positioning one end, then working it down around the tube. This allowed me to get it consistently tight. The only thing I would do differently would be to thin the glue a bit so it would not try to clump up so much.

    We found some wraps to be too long around the tube circumference and some too short. Overtrimming some of the long ones made them too short, giving us yet another gap to fill.

    Wrap #1 or #2 was too wide. We trimmed wrap #2, but in hindsight, maybe it was wrap #1 which was oversized as there was a flat strip along its lower edge below the corrugations.
  10. Filling - There was Fill and Finish dust all over the room when we were done, much of it on the tank fairing.
  11. Deciding when to attach details and when to paint - We decided to paint the tank tubes white and black before assembly to avoid some expected difficult masking later. But four of the models were built with the tanks 45 degrees off or so we thought. After turning those black tanks white, we realized those were correct after all, so we had to make the other black tanks white too.

    The discharge tubes and vector control housings were attached after painting. The retrorocket housings should have been as well so that we would not have to mask around them.
  12. Attaching details - I shaved a few layers off of the bottom side of the tunnels on the second stage where they overlapped the wrap to make them lie flat and eliminate the gap between the tunnel and the bare tube.
  13. Masking - One team member turned us on to Tamiya yellow masking tape. It is pricy, but worked wonderfully. Liquid masking film did not want to cooperate for us. Blue painter's tape just did not want to stick to itself, but worked OK.

    This turned out to be one of the most time-consuming tasks. We double checked each others' work to catch most errors.

    It turned out that masking the tanks was not as difficult as we had feared - copy paper fit well between the tanks. The decision to attach the antenna panels after painting greatly simplified tank masking.

    One side of the POS III fin was wrong in the instructions - a team member faithfully duplicated the error to the amusement of the rest of us.
  14. Painting - I did not have confidence in my ability with a rattlecan, so deferred to other members of the team. This was not the time to be learning.

    We chose to spray on black paint instead of using a brush.
  15. Attaching parts after painting - Mostly with CA, though Aleen's Tacky Glue was used on some parts since these are going to be display models.
  16. Applying decals - I used scissors to trim close to the markings and made no sharp concave corners. I avoided the knife as the slightest nick would cause a decal to tend to tear. Once I learned that lesson many years ago, decalling had been easy and fun for me. Instead of fishing them out of a bowl of water, I found that using a puddle on a cutting mat was an easier way to wet the smaller markings.
  17. Drawing straight lines on a curved surface - Nobody felt like doing this freehand, so we found some 1/64" wide trim tape. A cut down copy of the LEM shroud pattern made a great template for marking the base of the doors. We should have used it for gluing on the latch pads as well.
  18. Assembling plastic parts - The wire from the Testors plastic cement was a great way to apply a tiny bit of glue.

    Having two of the tower legs split made for a stronger part when assembled, but special attention was needed to make the ends fit properly into the holes in the BPC and escape motor skirt.

    For that little ring in the tower, practice inserting it several times, apply glue to the four pads in the tower then do it one more time to fix it into place.
  19. Fabricating plastic parts - One of the tiny service module thruster nozzles vanished on me and before I could contribute one from my personal Apogee capsule, a team member made a replacement from scrap sprue material. Thanks, Jack!
  20. Detailing - Silver Monokote stuck to the service module wrap looks great, especially after satin clear is applied.
Reply With Quote