Newbie no more - Building the Revell 1/72 Gato

[trout]

Chris - Wow thank you! You are very kind. Not a bad suggestion to build a test tank.

[oztruck]

The "TUB' test is always a lot of fun but I have found it is a lot better on the old back and knees to use my 6' X 4' box trailer.

I got some plastic pond sheeting and lined my trailer with it, then filled the trailer with water. What I now have is a "Test Tank" that is long enough to float most of my boats and deep enough to completely submerge the subs for testing.

The best part is that I don't have to bend over to see what is going on with the boats. and getting them in and out is a lot less drama than walking a dripping sub out from the bathroom to where it is to be worked on, especially when the wife is looking.

Luv your work and keep the photos coming

Cheers Chris.

[trout]

Jay, Your build coming along great! Thank you for the encouragement on the search for foam. I will keep looking for the pink stuff. So far it looks like around here, everything is the fiber insulation. Yes, I have begun playing with the radio. Do you know what I learned? Things change (can you believe it?). My receiver (Futaba) has G type plugs.

G to the left, J to the right. The radio works great with the modifications I did. My old batteries were long gone, but I modified my TX to hold a newer battery pack (with AA rechargeable batteries) and the RX (for testing purposes) is using a battery pack with rechargeable AA batteries.
The new servos and receivers use J type or JR plugs. So I have choices. I can buy J pins and connectors and cut the cables on my old servos to use the J plug portion (cheapest, but time consuming) or buy pre made cables to convert the new G servos to J receiver (most expensive, but not time consuming) or a combination of buying G plug pigtails and J plug ends. All have pluses and minuses. BUT wait, David or Mike, will the SL-8 work with my old Futaba?


Not wanting to let the build be stagnant, began some details on the hull (I will post at a later date). I did rescan the line drawing in the Revell instructions to a higher resolution, and cleaned it up.

Will finish the drive shaft install on Wednesday (hopefully) and post the progress.
It is getting close to a tub test. I can't wait.

[beeryboats]

Tom,
You should be able to find that pink foam there somewhere. As hot as it is there, they use foam panels. If not I have a bunch here I bought for cutting foam wings. It would cost more to ship it than it's worth though. Keep looking for the pink stuff! Have you done any radio installation yet? I need to charge the radio before next weekend so it's up and running. This is the part I hate when it comes to building RC aircraft, rigging the radio. Looks like I may have to splice the larger aluminum tube to make it long enough to control the retract of the dive planes. And I asked David how to install the snort and glue the guide for the forward controls to the lexan tube.
Jay

[trout]

I went shopping for stuff.....I got the aluminum (aluminium for our proper english friends) tubes I needed, but I can't get Owens Corning Foam F-250? My Home Depot does not carry this - I guess being a warmer weather state gets factored in. Any other suggestions? What does a sheet run? Anyone needing to buy one I can go in with?

[He Who Shall Not Be Named]

Hey, I'm thrilled to see another one of these things go together.

David

[trout]

David, I see I did not make it clear in my posting, I am sorry about that. YES they did come in and I was able to mount the bearings. Thank you! David I can not thank you enough for the help you have provided.

[He Who Shall Not Be Named]

Good stuff! Love the semi-circular bearing foundations!

You did get the new shafts, right?

David

[trout]

Mike, I am keeping the pictures small so page loading times are quick (if you see any you want larger - go ahead)
To recap, the drive shafts were to parallel coming in and because of this the normal spot recommended for the propeller shaft bearing to be mounted would have meant the groove to allow clearance would have been through the hull. (note to anyone reading this building a Gato - put the collar, washers, bearing, and Dumas coupler on when aligning the propeller shaft and propellor shaft strut). What should have been done is a slightly increase of angle inward. Maybe my crayon drawing will make more sense.

I was going to make a new set of shafts and David saw my dilemma and offered to make the longer shafts for me. Thank you very much! You can see in the photo the bearing assembly and how much it needed to move forward.

With that in place, I used some sprue and heated it gently over a flame. Softening a longer length of the sprue to wrap around the bearing. It may take several times to heat and wrap before you get it where you want it. Did this need to be done this way? NO. I was already using the sprue for the pin to hold the WTC and thought why not. Have fun. You could have just as easily used CA and baking powder only.

I used a cheap and not the most accurate way to measure how much to trim off the sprue wrap. Using a toothpick, I clipped off the point and placed this next to the bearing. Marked the height from the inside of the hull to the top of the bearing with a pen.

Then using my highly accurate (inaccurate) measurement, I trimmed the plastic sprue. I did not need to be super accurate. In reality, I only expected one leg to attach to the hull. This would leave enough play so that I am not pulling the bearing away from the hull or pushing it into the hull and causing a binding. If I did get both to touch the hull and not cause a binding then that is a bonus. There was no intention of spending hours on this.

Plastic cohesive was used to bind one leg to the hull (keeping shaft in for alignment). Then using CA and baking powder began filling around the bearing.

Checked shaft rotation and move on.
Next I needed to install the WTC. Earlier in an post I shared the problem of the front of the WTC being pushed up above the waterline and trapping air. The suggestion was to cut it shorter by David and remove the alignment peg for the hull in the front by Jay. Removing the peg, I believe, did help. If nothing else the WTC slides smoother going forward. David’s suggestion to shorten the WTC helped the most. I left 4” in the battery compartment to hold the LiPo packs I have.
To begin cutting, I wrapped blue painters tape at the location I marked. Measured again to make sure and began cutting. I took very small cuts, turned the WTC and took a small cut. I did this over and over again scoring the tube a little deeper with each rotation. I took my time! Did not want to crack, break, or melt the tube (especially since I do not know the properties of the Lexan tube).

I did not keep track of the time, but finally my jeweler's saw broke through. Once that happened the rest of the sawing went quickly.

Next step was to put a chamfered edge using my x-acto knife. It was surprising how easily it was to cut. After I trimmed what I thought was enough, I used a half-round file to even out and smooth over my knife trimming.

The final test is will the end cap fit? And it did.



On my WTC there was a hole already drilled into it to accept the pin that is to be attached to the hull. It is off center and that poses some issues with how easy it would lift out. Too long of a pin and there would not be enough diagonal travel room to slide off the pin. Too short and it will never engage the hole.
I needed to find out how much room was there between the hull and the WTC. Grabbing a scra* piece of 1/8” brass (I was practicing putting on threads) checked to see fit. I needed to grind down the threads, but for testing it was fine.

Put a piece of Play-Doh (Thank you Sam) on the end of the pin and gently pressed it against the WTC.

I aligned the WTC into the hull making sure that the vent was centered and at the apex of the WTC. Pressed it down and allowed the Play-Doh to squish out. Realizing that it would take a full day for the Play-Doh to dry out, I had to come up with something quicker. Super Sculpey to the rescue. This stuff is a clay type consistency that will harden when put in the oven at 275 degrees for 10 - 15 minutes. So I took the WTC out. Carefully removed the Play-Doh and put a ball of super sculpey on. Squished it down and removed the WTC one more time. As it happened to be, my wife was just done using the oven and it was already pre-heated. I was a little vague about why I needed the oven and slid my mold on a piece of aluminum foil into the oven. She caught me and when I explained what I was doing she did not mind. I love my wife! I compared the sculpey (which is now hard as a rock) with the Play-Doh and came up with how big the gap is.
Now I used a piece of sprue to make a base for the pin. Heating up the plastic on the gas stove (I was empowered since Tina did not mind the sculpey in the oven - what’s a little plastic over the stove?) I got it nice and soft. Then quickly pressed it against a safe hard surface. In my case it was a small block of steel.

This created a blob at the bottom. Oh, if you try to rush it or get the plastic too close to the flame, it ignites and turns your plastic into a blackened blob, I did this for demonstration purposes only (it still worked).

I sanded the bottom of the blob to rough it up for cohesion. And fortunately the red sculpey left a little stain on the hull so I knew where to sand to rough up the area.

I carefully drilled a 1/8” hole into the top of the sprue and inserted the brass pin. Cut the pin short since the plastic blob would be close to the WTC. Rounded the pin end so as not to scratch my precious. And placed a small thread of sculpey around the pin. Pressed the pin and blob to the WTC and placed it in the hull. Again being careful to align the WTC. From underneath I was able to add the cohesive through one of the flood holes. Let it dry. Removed the WTC and did the CA and baking powder filler.

And here is the final look.

I should have drilled my own hole for a pin directly underneath. Then placed a block at the end of the WTC and when it is dropped straight down, the pin will automagically go in. As it is now, it is a little tough finding the hole. Can you see it?

Niether can I.

[He Who Shall Not Be Named]

filler/putty/primer/paint/weathering are aquired arts when it comes to selection, area of use, and application. You'll get the hang of 'em. Just keep plugging away till you find the technique you're comfortable with.

And I should have mentioned the addeded benifit of placing the heavy brass rub-strip way down low -- indeed it does increase the metacentric height. Good catch.

David

[trout]

Thank you on the paint tips. I will continue to play until I conquer it or asphyxiate myself!
Armor plate sounds good to me! but is there any other benefit other than warm fuzzies? Does having the brass weight that low on the ship help with stability or with the metacenter?

[He Who Shall Not Be Named]

Cut the primer about 50/50 with lacquer thinner and set the gun for about 20PSI and blast away. If you're using an external mix, single-action type, use the #3 (big) tip and needle. Get up close and get the primer down wet.

I don't usually attached the brass strip to the keel of the GATO's I build. But, if you want armor plating, attached it with both 2-56 flate head screws and CA.

David

[trout]

Jay, I will be doing a primer and cutting out the area under the sail. The weight removed is probably offset by the weight added by the magnets, but the bigger benefit I see is allowing air to escape. I plan on hiding some holes in the conning tower to allow the air out.

I played with the sand n fill primer. WOW this stuff dries real fast. Once mixed it reminded me of the dope paints I used as a kid on some planes and gliders. I had to clear my air brush many times in the short amount of time because of clogging and spitting dried pieces. I will use a different set up to see if I can get a better flow. David, do you have to use a higher psi to get this to cover in a nice wet flow? or what suggestions can you offer?
Do I need to cover the whole ship in this primer or can I use a Krylon paint in a can to base coat the majority?

David, the grounding scratches you mention, in older builds and cabal reports you would put in a brass strip on the keel. Do you still do that? What is the best way to affix the strip to the hull? If you stopped putting it in may I ask why?

[He Who Shall Not Be Named]

You already cut enough dead-weight away ... don't get anal here! As is your boat should reach designed waterline in surfaced trim.

Mike's idea!? Hurumph! (yes, it's a good idea).

David,

[beeryboats]

Just get it to primer gray and get it operational -- that's what I do with a new build. You can paint and weather it anytime. Kick it around first; get those invitable grounding scratches on the lower bow; put your fat fingers through the railing a few times; and don't forget to drop it off the cars back seat at least once.

Get all those invitable 'life lessons' out of the way, and only then, break out the putty and filler, paint and weathering kit -- do the beauty work over the winter while you have time and nothing else to do.

David

True words of wisdom. What's your take on cutting out most of the unseen part of the deck under the conning tower but leaving a strip for a magnet? I liked MIke's idea of holding the gun ahd tower on with a rare earth magnet.
Jay