Skipjack 1/72

[greenman407]

Man! I hit the length of the rod and adjustments perfect the first time. No need to adjust............except there is flex in the sail planes. The culprit is the flexing of the brass pushrod coming out of the subdriver and the bent double 90 degree extension that attaches to the magnets. For strength, these 1/16" pushrods arnt as strong as the 1/8" ones of old. Well, no matter. We will work with it. Im going to make a bracket as I said before and mount it to the engine bulkhead leading edge to help restrict some of that flex.

[greenman407]

Made this quick little bracket and CAed it in place. It helps a little but, I think that the bellcrank system that Dave used on the Gato Subdriver would be more suitable. To describe what Im talking about is that you move your stick three or 4 detents before it starts to move and then it jumps and catches up. Then you move about three or 4 detents more before it starts to move and then it jumps. Under the pressure of the water streaming over it I would think that it would be much worse. Not good for fine tuning periscope depth.

[greenman407]

Installed double magnets and a couple of sleeves to prevent unwanted movement during separation. Ill also move the pushrod engagement position on the servo horn from the third hole into the forth hole to see if that helps dial out some of the delay of movement of the planes when prompted. I can always dial back on the endpoints in the radio to prevent too much range of movement. Another thing that I noticed was that the aluminum tray that all the servos and stuff are attached to also has a tendency to flex and move when the servos operate. This will call for installing a gusset or two to stop that sort of thing.

[He Who Shall Not Be Named]

As to the device tray flexing: insure that your pushrods are not binding -- take care to bend the forward ends to make up to the servo bell-cranks so that the pushrods are in the seals 'sweet-spot'. And lubricate the pushrods where they pass through the seals with silicon grease.

Looking good, Mark.

M

[He Who Shall Not Be Named]

As to the device tray flexing: insure that your pushrods are not binding -- take care to bend the forward ends to make up to the servo bell-cranks so that the pushrods are in the seals 'sweet-spot'. And lubricate the pushrods where they pass through the seals with silicon grease.

Looking good, Mark.

M

[greenman407]

Thanks Dave, Ill get some silicone grease on there.

[alad61]

However, the sail planes are not critical to operation as most of the control, I believe, will rest with the stern planes. Sail planes are just the icing on the cake.

I have to disagree here Mark. With the rear planes running off the auto leveler the sail planes are most defiantly critical. During a tight high speed turn the sub wants to bank and dive with the leveler doing its best to counteract but a little rise on the sail planes and not only does the boat bank less but it maintains a nice level bubble by helping the adf do its job better. For me anyway those sail planes are very responsive, easy to use and are more than just eye candy on the sub. They don't need a lot of travel to do the job so the risk of magnet separation from excess water pressure is pretty minimal.

[greenman407]

I kinda cant argue with that, considering I haven't had mine in the water yet. However, Im speaking from History. Look at all the submarines in the world that dont have sail planes. My other submarines work great also without them. Even the ones with Bow planes, dont really need them. They somewhat enhance operations but they aren't critical.

[greenman407]

Dual magnet setup on linkages. When I put the top of the rear section on it, by design,it pinches the control surfaces. You will probably need to do some work here to prevent binding. I used a baby rat tail file and open up(a little bit) the holes that the dive planes shafts go thru on the plastic hull. You dont want to open them up too much because then your planes will flop around. But if you leave them as they are they will bind. You may have to tweak the white metal yoke that attaches your dive planes together so that the planes are perfectly in line(up and down, left and right) so that when it rotates it doesnt walk out. Also you may have to grind a little off the inside of the hull at that point too if the yoke binds there.

[greenman407]

I have to disagree here Mark. With the rear planes running off the auto leveler the sail planes are most defiantly critical. During a tight high speed turn the sub wants to bank and dive with the leveler doing its best to counteract but a little rise on the sail planes and not only does the boat bank less but it maintains a nice level bubble by helping the adf do its job better. For me anyway those sail planes are very responsive, easy to use and are more than just eye candy on the sub. They don't need a lot of travel to do the job so the risk of magnet separation from excess water pressure is pretty minimal.

Alec, by saying that the rear planes on yours are running off the auto leveler,are you saying that you are not controlling the rear planes with your radio?

[alad61]

Yep the only time I have used the rear planes is on a surface run if the bow dips under speed or if I get a bit of cavitation on the prop with choppy waters or emptying the ballast a bit to much as I have it just a bit high on the waterline. For a submerged run I just blow the ballast let the boat cruise down to it's submerged trim which puts the sail planes just under the surface and use them to control her depth.

[greenman407]

Just for fun, try using the stern planes to set your depth and then fine tune it with the sail planes. I think your going to find a whole lot more control using the stern planes. The ADF will work in concert with your inputs on the stern planes.
Just as an experiment. If you dont like it, then go back to the way you were doing it. Whateverworksforya. Ive had my Albacore down to 30 ft. plus at Blue Springs in crystal clear water. Wish I still had the video, it got lost at Youtube. Anyway,in that deep,narrow gorge,I never could have got it down into there without the stern planes.

[greenman407]

Not to change the subject or anything but, here is a 3 cell LIPO cut partially open. Note that there are six distinct sections. Apparently two together make one cell. This seems probable since each two are insulated from the other pairs. The silver is apparently aluminum foil.

[greenman407]

Here you can see Im making up the drive shaft. The tube used here is a brass 7/32". I cut mine at 8 and 1/2" long(actual brass length). Yours may vary due to exact placement of your subdriver. I make mine up to where there is just a little bit of slop between the Dumas teflon end and the brass drive dog. As my previous practice has been Im going to drill thru the shaft at the teflon ends(Dumas) and pin it with a small dia. brass wire and CA the wire to the brass tube.. You see, CA and Teflon dont cooperate well with each other, I have had these come loose before, thus this practice. A little insurance. Also, while I was at it I noticed that the white metal control yoke for the rudders sits too low in the sub.Checking clearance with the underside of the top cone, I installed this brass washer underneath the yoke and that took care of it. We dont want the yoke rubbing on the spinning drive shaft and at the same time restricting rudder throw. Also its nice that Dave has made flat spots on the control shafts. Less chance of them coming loose. Dont forget to blue loctite all the grub screws. The Allen wrench that fits them is tiny. .050.

[greenman407]

Notice also in this picture that I have bent the pushrods so that the magnets meet in the same plane for better "stick". Also, its just "good form". Youll also notice the "band-aid". Yeah. When you goof and get your length wrong on the pushrods that you cannot adjust out, just cut them and splice it back with a piece of 3/32" brass tube. Set it at the right length and then a drop of thin CA at both ends will hold it fast. Mums the word.