Newbie no more - Building the Revell 1/72 Gato

[trout]

No help on the propellor?


welded the bow and stern onto the hull. Exciting to see her come together! I am a proud owner of a WTC from D&E. So, I was able to remove the cross braces moving my total weight off the top to 179.6 g or 6.3352 oz! and get it to drop in. Where do I know to place it in the sub? Is there a distance or measurement for placement?

Moving back to deck construction, now that I knew what cross members I would not have, I place the deck on the hull and checked fit. It did not bow down and held its shape. I still will add a reinforcement of some type - working on ideas for that.
So time to add the front vent plates. Before I could glue them, I needed to remove the forward portion of the pin receptacles. I want to be able to slide the deck forward and have several areas engage to hold the deck down. So I drilled, cut, shaped, trimmed, and tested the cutouts to the corresponding pins until with a small amount of resistance it slid in.

A closer look

Now is the time to use cohesive on the part to commit my idea.
I had to be creative here to get the fit I wanted. So using toothpicks as little leverages, I adjusted the fit of the side to the deck. Some toothpicks were placed to move the top of the vent outward.

and others were to lift the piece just enough.

Now came the test to see if it would work. My first couple of tugs the deck did not slide. GRRRRR! I took a deep breath and rather than rip it apart, I gently tried again....it came apart just the way it was supposed to! After a brief dance around the room (definitely no photos of that), I went ahead and added some side reinforcement.

Reattached the top to make sure it works the way it should and it did again. There is a click when it engages. Not sure if I need to open the sides a little more or leave it and give it time to either grow on me or push me to fix.

I am pleased with the results. There is a gap at the bow, but I can fill that and narrow the space.

Now to mounting the wtc and dive controls and propellor.

[trout]

Back to the aft planes/rudder/et al.
After playing with the rudder,testing fit, and preparing to paint, the brass rod came loose from the rudder and would pivot. So I needed to do few things. I marked where the brass entered and exited the rudder and skag piece. Roughed up the brass where it will be buried in the rudder and kept the areas that touch the bearings smooth. I tested out the fit and drilled a very small hole just outside where the brass rod was traveling. Then I took a 1/16” drill and drilled the hole again. What was accomplished is I cut a notch out of the rudder shaft. Once the shaft is glued in, I will put a pin in to keep it locked in place. I put the shaft in, but leaving just the distance from the bottom of the rudder to the first bearing in the skag. Placed a drop of CA at the hole of the rudder (holding the aft upside down it will be the top) and at the point where the rod enters the rudder after leaving the bearing. Quickly pushed the rod to the correct spot and wiggled the skag to make sure it did not get glued. Then I put a length of 1/16” brass rod in as my pin. Cut the rod close to the rudder, CA’d it, and put baking powder over it to harden.

Filed and sanded the pin flush.

Once it all dried I tested again to see if the is any slip or issues and there were none.

I will make a correction to a prior post, I would need to either make the sprue/screw/skag filler longer and NOT cut the front at an angle or cut it to this height and cut the front at an angle. As it is, there is just enough play with the skag and rudder to get over the sprue filler. Had I made it taller, there would be another shame picture to show as I try to cut the sprue filler off.

I also cut a flat surface on the rudder shaft for the control horn’s set screw. You might be able to see it through the aft torpedo opening.

The replacement part came in and I got the shaft support, shaft tube, shaft installed. I used the D&E propellor for distance when I was adjusting it.

I CA'd the shaft tube and propellor support inside the hull. Now I will keep filling around the outside.

Got a moment? Lets talk about props. Here is a selection of props for the Gato. The plastic kit one measuring 32 mm, a brass prop that I got when I purchased a gentleman’s wtc and assorted pieces measuring 31.5 mm (looks like they just cast the model’s prop), a D&E white metal prop measuring just a hair short of 35mm looks like it is 34.9 mm, and finally a Raboesch prop (purchased from Caswell Inc.) measuring about 35 mm maybe the same as D&E. So which one is more scale like or does scale really matter here? Does the larger blade on the prop help performance? What are your thoughts?

Of these only the Raboesch propellors are threaded. Should I drill these out (if these are the ones you recommend) and mount them on the shaft?

[trout]

Thank you! You are the Master, I am the Padawan!

[He Who Shall Not Be Named]

Congratulations, that's about 2.5 cubic inches of ballast tank you won't need (I worked this out for the GATO SD years ago). This demonstrates why it's important to keep the above waterline structures as light in weight as possible.

I like your methodical approach to this project -- a well written and illustrated build log.

David,

[trout]

Just a quick note. I have been doing some cleanup and weighed the pieces I took out of the top of the hull, bow and stern. It came out to be 163 g = 5.74965 oz (at minimum) and I still have cross members to cut out.

[trout]

O.K. - I can do that!

[He Who Shall Not Be Named]

Instead of using that big clevis as the interface item between pushrod and stern plane operating shaft bell-crank, simply put a Z-bend at the after end of the pushrod and use that to hold the pushrod to the bell-crank -- you can thread that assembly into the skeg for final assembly, Trout.

David,

[trout]

I went ahead and worked on preparing the bow planes for priming. I CA’d the pin in and made sure enough CA was applied to coat all surfaces. Went ahead and sprinkled with baking soda then clean off the lose baking powder to see the coverage. This exposed areas that the CA did not get into and so I filled as needed. Then filed, ground, sanded the pins down to contour the dive plane.


The aft planes needed a clevis attached to it. It took me a while to find one that I could solder to 1/16” brass rod. I brought them (two in a pack), but the pin was too big to go through the dive plane control arm hole. And if I tried to drill it out, there would not be any metal left to create a hole. So, the logical thing to do (in my mind) was to make the pin smaller. Oh by the way, if you pull a clevis too far apart it goes “Sprongg” and flies apart. So I began attacking the pin on the one clevis I had left. Gently worked around the pin with a file until the diameter fit the control arm hole.



Can someone tell me how I attach this to the control arm when I assemble this inside? I can not string it through the opening in the skag unless I want to make a big opening (I would prefer not to)


Time to attach the skag/propellor strut. I glued just the strut part, the very most forward area. Then cut an angle in that would offer an additional holding factor. Maybe the picture will make more sense. The rear portion of the skag hooks under the glued front.

Marked where I wanted the screws to go, but one area had nothing to support it.


So.... break out the sprue. I melted the sprue and quickly flattened it. Then sanded and ground it down to fit. Applied a generous amount of cohesive to the sprue and surrounding areas.


When I cut the sprue off, I left a small amount above the skag. Had I been smarter, I would have left a larger portion on because it helps align and support the skag/propellor support (much like a biscuit cut or plate cut in wood working) and give me more to screw into. Oh well next time. Then I drilled .063” hole and threaded a stainless steel 2-56 3/8” screw in. It WAS just that easy. Thank you David for sharing that tip! In retrospect next time I would drill a 1/16” then follow that with .063” 3/4th the way through. Leaving the last 1/4 the more tighter grip on the threads. It may not matter, just a thought for next time.

Put it all together and tested range of movement of the rudder and planes. It works!

I sometimes over think things and other times I do not think it through enough. Take the deck for example. Since I will be removing many of the cross braces in the superstructure, I thought glue the deck first on a flat surface, since the deck is flat from the photos and drawings I looked at. So I broke out the wax paper and placed the deck upside down to glue. Note, the deck supplied in the kit is not flat there are “things” protruding up (well down now that I flipped it over). I over came that by angling the protrusions off the edge of the table. And applying cohesive glue to it. Held it flat and weighed it down. Then added the support pieces to strengthen the joint.

The part I did not think about so much is glue leaking (I did put wax paper down). I slopped on a lot of glue with the center and aft section. Well here is another shame picture....

But when I did the bow I was less liberal in the amount of glue (at first) then gradually added more. This worked better.

The side pieces are not glued yet, but I have very small spaces between the bow and midsection.


I am relatively sure I can fix my shame deck section, so once painted you will not see it. Let us keep that as a secret or better yet, forget about it altogether.

[trout]

That's it? No tap and die set? No big expenses? I am in shock.....But happy :)
Thank you for the tip. I will play tonight.

[He Who Shall Not Be Named]

If you're talking about styrene: Just drill a 1/16" (using a .063" drill bit will make the work go easier) hole and use the screw itself to cut the threads.

David

[trout]

I need your help, I want to put a couple of 2-56 screws into my sub and I have never tapped a hole before. How do I do this?
Thank you!
Peace,
Tom

[trout]

I could not leave well enough alone and I noticed one pin that goes through one of the bow plane operating shafts was slightly crooked and I had some resistance in the bore of the bow plane shaft and wanted to ream it out a little too. After disassembling the dive planes, I noticed there is a slight angle in the bow plane operating shafts ends that receive the dive plane and I installed it BACKWARDS. Once I rolled them over and facing the correct way, everything fit better and I got the 90 degree angle on the bow planes I was looking for.
Here is a drawing with exaggerated angles to demonstrate what I mean.

Complete deployment of front dive planes.

You might be able to see it here, the blue/green piece that the plane attaches to has a few degrees angle. And that angle runs parallel with the angle of the hull at that point.

Now the plane has room to move and my resistance disappeared, so the movement is smooth retracting and deploying. My range of up or down bow planes increased because the planes were not hitting the hull.


In an effort not to repeat installing them wrong again, I marked them left top and right top (should be port and starboard, I know...) Also another benefit the plane hugs the side of the hull better, before the forward edge seemed to stick out a little (thats because it did - amazing what a few degrees can do).

[He Who Shall Not Be Named]

I honestly don't know if the GATO/BALAO/TENCH class bow planes, when deployed, fell across a horizontal plane or had a bit of dihedral to them. Anyway, the bow planes on my boat have a bit of dihedral like yours, and I'm good with it.

It could be argued: If I had provided the right parts to your GATO fittings kit, to begine with, you would not have had to put our 'customer service' to the test. Anyway, thanks for the nice words.

David,

[trout]

David you are the man! What incredible customer service! Thank you so much! I had an email this morning (Wednesday) that a new set of propeller shaft struts were on their way. I know we all want to pinch a penny here and there, but there are times when NOT to. Not that Caswell, D&E, Mike, David et. al. are outlandish in prices, they are fair prices for quality work (at least that is what I have found so far). BUT the icing on the cake is what a company does when there is a problem or error. David and Mike you know how to take care of your customers. Period. Back to the build.
Marking where the stern tube exits the hull is pretty simple, just use the plastic part that came with the kit and trace around it. I marked also where the shaft stern tube ends with tape, so I can have some semblance of symmetry.

Then slowly begin to cut out the area for the shaft support struts and shaft stern tubes. I am not sure how many times I stopped to check, but this will take awhile.


Finally I have one side done. After I get the replacement part, I will work on the other side then glue these in. For now, lets move onto the bow planes.
Using a bud burr, I channeled out the area for the pins.




Checked out that the route that was cut for the 1/16” brass rods was deep enough.

Glued them together (DVD very helpful) and once dried hand drilled out the holes to clean out any glue or alignment issues due to sanding.

Temporarily installed the dive planes, checked the movement, and found that I did not make the oval big enough - grrrr. O.K. not that big of an issue just in disassembling the retract fell off. If I mounted the retract system too low it would lose mesh in the gears when the dive planes are up. Mounting the retract system higher up solved that problem.











When I mounted it high I got great retract, but I am not sure about the deployed/down position. It is not completely horizontal and forming a 90 degree angle.


I do have some space between the bow plane operating shaft, Hmm if I bring those closer, I will lose some surface/dive motion because the planes collide with the hull. I could trim the planes. I will test that tomorrow. Is the angle O.K. if left like this? Your thoughts are appreciated. If not, is the solution to lower the retract a smidgen or two?

[trout]

Cleaned up the white metal parts following the DVD (again a ton of tips and instruction).

A sprue was pulled over a flame and bent to give me a hook to dip the parts into ferric chloride acid. This will etch the metal and give a good hold to the primer paint.


Then you need to neutralize the acid. This is done with water and baking soda (or sodium bicarbonate). I saturated the water solution by adding baking soda until no more could dissolve and a small amount settled at the bottom. When you dip your etched piece it will bubble as the acid and basic solution react with one another.

Here is the contrast you can see. The darker parts on the right are the ones that have been etched.

Began to install the propellor shaft strut. There is an indentation were the plastic part would connect that I used to open a hole that closely matched the metal strut. Looks O.K., there is a little play for alignment with the shaft.

I thought I was going crazy and kept grabbing the left propeller shaft strut until I realized I do not have a right one, just two lefts. Help!