1/96 ScaleShips Oscar II

[HardRock]

Its Brad's 1/72 scale Tyhoon. Either that or an eight foot long croc.

[Davidh]

I think that's actually pat drakes U-995 type 7C.

Dave h

[HardRock]

I stand corrected..... different croc.

[HardRock]

I've had a problem with the vent valve in the Oscar taking a long time to vent the tank. Seems like there's so much back pressure in there that the flap valve does not want to release. So I've been working on a simple O ring valve that will give me a good seal and is easy to replace. The inner stem is solid brass and I'm hoping that it will open the valve under its own weight. We'll see.

Oh, and I did indulge in the work of the devil and print the valve spacer and housing.

[greenman407]

Carry on sir. I had similar troubles. Mine would vent but took a great deal of time, partly due to my requesting an especially large ballast tank. I took off the top of the valve and drilled it out, I think a full 1/16" bigger in diameter. BOY it vented then!

[HardRock]

Doing some pool tests this afternoon with a modified test rig. Beware tampering with the Dragon's designs. I'm keeing a sparp lookout for thunderbolts and lightening - whilst half expecting to hear the deep, rumbling voice of HWSNBN between the thunder claps saying, "You people; I give you perfection and you keep ****ing with it"!

[He Who Shall Not Be Named]

Doing some pool tests this afternoon with a modified test rig. Beware tampering with the Dragon's designs. I'm keeing a sparp lookout for thunderbolts and lightening - whilst half expecting to hear the deep, rumbling voice of HWSNBN between the thunder claps saying, "You people; I give you perfection and you keep ****ing with it"!

Naw .... you're right to ***** about that vent valve I designed. Though improved over the years, it remains the Achilles heel of the SD. Carry on, good sirs ... if you bums come up with something I like, I'm gonna steal it!

M

[HardRock]

Just came in from the pool, because there is an actual thunderstorme overhead. In any case the rig worked quite well. It vents very enthusiastically and seals with minimum pressure on the base of the shaft. Time to be brave and chop a hole in the top of the Oscar SD and try it for real.

[redboat219]

Can you post photos of the test rig?

[redboat219]

👽👻Happy Halloween💀🎃

[HardRock]

Can you post photos of the test rig?

Dis da ting. Its just a small ballast tank with the standard control arm. The test valve is RTV'd to the top so that I can rip it off and fit another one relatively quickly.

[HardRock]

Back to the drawing board - literaly. The lever actuator can't generate enough force to seat the O ring consistently. Might have to go to some kind of screw closure to get enough force.

[HardRock]

Meanwhile, I am determined to get the forward plane retract system working reliably. So I pulled all the old set up out and started again. On testing I discovered a small leak in the gear pump and a bit of weeping around the tray fixing bolts. Rather than run bolts through the bulkhead again, I decided to fix the internals using a press fit ring with everything fixed to that. Looks like this:


The ring sits flush with the internal face of the bulkhead. Its quite tight but it will also have a dowl somewhere along the rim that will locate it in the right orientation.


I added a mount for the gear pump that drives the periscope system.


The tray that mounts the linear servo slots into two cut outs on either side of the ring.


And the whole thing goes into the front dry space with the back end of the linear servo protrusing into a new water tight extension through the intermediate bulkhead.

[HardRock]

I didn't know that "protrusing" was a word. Maybe its protruding.

[greenman407]

So Hardrock, hows the Oscar coming along? Im getting ready to pull mine back down off the shelf and begin again.