The Build Begins!
Here is my build of the 1:100 Saturn V Estes kit, hopefully complete for flight on 20th July for the 50th anniversary of the moon landing. Yes, I know they launched on the 16th, but the 20th is a Saturday and more convenient
. It also happens to be the day they (Armstrong and Aldrin) set foot on the moon.Glues
For this project I am using a gaggle of glues:
• Yellow wood glue (aliphatic resin glue)
• Model cement (Plastic Magic, Tamiya Plastic Cement, or similar)
• Zap-a-Gap medium CA (cyanoacrylate, aka superglue)
• BSI 30min epoxy
And I will also be using Tamiya Putty for creating seams, fillets and filling the styrene plastic wraps.Also needed:
• Sharp Scalpels
• Steel Rule
• Sharp Pencil
• Popsicle Sticks and Skewers
• Nail File Sticks (like popsicle sticks but abrasive)
• Rubber Bands
• Patience and Steady Hands!!!Motor Mount and Stuffer Tube
Not much to say about this part. Just follow the instructions. One thing I did do was to take a hole punch (standard paper type) and punch one hole in each of the centering rings. That will allow me to use an internal launch rail, and to not have ugly launch lugs on the outside of the airframe.
Once the holes are aligned the entire assembly was set aside to cure.
FYI, the purpose of the stuffer tube is to carry the ejection gases from the motor to the parachute compartment. That way there is enough oomph to eject the chutes, without having to pressurise an enormous airframe along the way.Main Airframe
The main airframe was marked as per the instructions. The motor tube assembly was test fitted and found to be a little sloppy. I cut a couple of thin strips (2mm wide) from normal photocopy paper and glued them (CA) onto the outer edges of the centering rings. This increased the OD and made for a better fit. Once cured, the assembly was fitted into the airframe and glued in place with yellow glue (not too much or the airframe shrinks and deforms as this glue cures).
Next up was to insert the reinforcing ring internally to the rear of the airframe. Note that this is a seriously tight fit. It will go without sanding, but it won’t go easily. Don’t make the mistake I did of putting glue on the internal airframe with the expectation to slide the ring to its final resting place. Does not work. If I did this again, I would slide it to the correct position and just put a bead of glue on either end of it. Other people have been known to cut the ring, removing a thin sliver of material and then gluing it in place.Display Engines
At this point I felt like assembling the five F1 display engines to their bulkhead. These are injection moulded parts so they were carefully cut with a scalpel (don’t break them out if you want a good finish) out of their frames. Any excess flash from the manufacturing process was removed and mating parts checked for fit. Sandpaper was used carefully in a couple of locations to get a really close fit. Make sure you don’t sand or cut off the little pips that help line up the two halves of the engines
So, working one engine at a time, the halves are held together and the registration very carefully eyeballed to minimise the visibility of the seam. A tiny drop of plastic cement is applied to tack it in place. Move to the other end of the seam and tack it there. Move to the other side of the bell and repeat, and finally at the turbopump arm. Once all the tacking has held you can apply a judicious amount of cement along all the seams. Remember that you only need to touch the seam and if you have fitted it properly capillary action does the rest.
Repeat x 5.
I painted them at this point in a metallic charcoal color (spray). The white card bulkhead was painted gloss black, also in preparation for adding the motors. The assembly was completed as per the instructions.
I wish I had done what was done on this website for a more complete scale treatment: http://modelrocketbuilding.blogspot.com ... e.html?m=1
Lots of other good tips for building in that blog also.
I might end up changing my display nozzles to include this style bulkhead, maybe…Escape Tower
Next up I tackled the escape tower. The parts were carefully cut from the frame using the scalpel, and any flash from the moulding process is cut off now too. I basically followed the instructions for this part, assembling the framework as instructed, but without the circular piece yet. The pieces are held in place with one hand while a small amount of plastic cement is daubed on each joint. Capillary action sucks the glue into the joint where it softens and joins the plastic parts. Go easy with the glue, a little goes a long way, especially if the joint is very closely fitted.
Once the truss structure is glued, you can take the circular piece and place it on the end of a pencil, then push it into place in the tower. A gentle push will have it seat into the grooves in the other part and hold nicely. A little plastic cement on the four contact points completes the job.
Now you can also add the four nozzles to the LES motor cone, taking care to remove any flash before gluing any parts. This can then be glued to the tower, and that assembly glued to the command module (CM). Do this by the usual capillary method.
Once set you can add the LES motor tube and nosecone to that assembly. I glue both ends of the LES motor tube using the yellow glue. Remember the basic technique of applying the glue to the internal tube to make sure the excess glue goes into the tube and is not visible on the outside
To finally complete the CM you need to add the clay nose weights which are important to the flight stability of the rocket. Four pats of clay are provided. The instructions say to use two. If you are going to build a little heavier than ultra light you might want to consider adding the other two pats. I decided to go with four, as I don’t want a model that I have put this much time into to go skywriting, and I have heard of some people having this happen. Kneed the clay and pack it into the CM. Once complete, add the plastic cover over the rear of the CM and glue using the usual capillary method. Done!Fins
While I was doing the CM/LES I decided it was a good time to glue the fins also. They are injection moulded and the parts are separated from the frame by scalpel, edges cleaned up (scalpel, sandpaper) until the fit of each half is very close, and glued with the cement while holding the parts together by hand. Use your eyes to make sure the seams are in exactly the right location for good workmanship. Once set, a light sand of the edges means you can’t even see the seams.Third Stage
The central core for the third stage was next. The instructions were followed, with some minor alterations. I changed the recovery loop to Kevlar that I had laying around, and I also made sure the centering rings had the requisite holes for the internal launch rail.Forming the Transition
The cardboard transition was cut out of the larger piece of cardboard. The instructions suggest you cut it larger and longer than the lines indicate. That way you can whittle it down till you get an exact fit, and not have any gaps. Make sure you make it longer than it was on the lines too, which helps in getting the ends together. I then very carefully fitted the transition so the upper and lower diameters were right. The lower diameter is just a little larger than the tube it is transitioning to. That is so it sits on the main airframe with a little overlap. It isn’t much, just a smidge. You might be surprised how long this takes. Once it is the right size it is completed, and then slid into position and glued, similar to what the instructions say. Don’t overdo the glue, as distortion can result.
Next up was the wrap that goes over this transition. Again, don’t cut it too short too quick, so you can allow for variations in the part it is gluing onto. Slowly cut it smaller until the upper diameter is right and the lower diameter meets the end of the cardboard transition. I glued the ends of this together with a small lap joint. Again, just hold everything in place with your fingers and apply the cement. I also put on some sticky tape to hold it in place while the joint set.
At this point you have a wrap the right shape but not fixed in place. I measured up 4g (2g +2g) of the BSI epoxy, mixed and then applied it using a gloved hand to the cardboard transition. The wrap was then slid into place and patted down. This is where patience earlier in the fitting makes this part a breeze
Next up was the wrap directly above the one we just applied. Again, careful trimming and fitting to get the seam just right and bottom end neatly trimmed. I generally use less margin on these wraps than the 1/16” the instructions suggest. I guess I run about 1mm most of the time. Don’t worry about the top of this wrap as it is trimmed after the epoxy is set. Again, about 4g of BSI was mixed and applied to the tube. The wrap was applied, taking note of location and orientation. The ends were slightly stretched into place, overlapped and the cement applied. Try to aim for the pitch of the corrugations being the same as the rest of the wrap over the joint. The wrap is held in place with rubber bands while the epoxy cures, and a skewer under the bands keeps more pressure on the lap joint to make sure it isn’t proud of the rest of the wrap.
Once the glue is set you can trim the end of the wrap level with the end of the tube, and perhaps even sand for a nice even finish
.To be continued...