3/16" Shaft Seal Assembly Video

[QuarterMaster]

Really for the new Sailor, and anyone else who cares.

Still on my learning curve as a videographer, so be gentle lol!

RC Submarine 3/16" Shaft Seal Assembly

[salmon]

That is a good video you created! Thank you.

[QuarterMaster]

Though shown in the You Tube "Description", I should of added here.

Also, after a beatdown by my friendly videographer friend, I promise to maintain future video's ~5-10 minutes long. Even if I break 'em up into "Parts"

Here's EVERYTHING with orderable P/N's! Cup Seal's are the last item.

McMaster Carr
Easy-to-Form 260 Brass, Tube, 3/8" OD, 0.032" Wall Thickness, 1' Long Shaft Seal McMaster Carr 7782T42
Water-Resistant Dry-Running Sleeve Bearing, Flanged, for 3/16" Shaft Diameter, 5/16" OD, 1/4" Length Shaft Seal McMaster Carr 6362K211
Water-Resistant Dry-Running Sleeve Bearing, Rulon LR, for 3/16" Shaft Diameter, 5/16" OD, 1/4" Length Shaft Seal McMaster Carr 6362K111

The Oring Store
N70 Buna-N Nitrile 70 U-Cup Size: 3/16"ID X 5/16"OD X 1/16"CS Shaft Seal: 3/16" The O-Ring Store 626-008-5747

[jure george]

Hello Quarter Master

Thank You for posting your how to video, very helpful.

Would it be possible for you to include here a side length drawing of your insertion tool you used to set the bearings and o rings into the brass tube body, it would also help if you would include measurements for each section of the tool as well.

Also will this shaft seal work with air bag WTC systems that work on an internal vacuum?

Thanks again for your post.
George

[QuarterMaster]

Hello Quarter Master

Thank You for posting your how to video, very helpful.

Would it be possible for you to include here a side length drawing of your insertion tool you used to set the bearings and o rings into the brass tube body, it would also help if you would include measurements for each section of the tool as well.

Also will this shaft seal work with air bag WTC systems that work on an internal vacuum?

Thanks again for your post.
George

George,

1-Regarding your request, here is a quick sketch of the tool. You can see the dimensions match up with the insertion depths of the "Rulon" bearings on the Shaft Seal Sketch.


Shaft Seal


The venerable Cup Seal
With all due respect to the Godfather (of RC Submarines, I honor and show respect.....so now I kiss the ring of "Godfather" Skip Assay) who to my memory first introduced us to them, and any ME's lurking (THOR by thunder!!), please go easy if I botch the following explanation.

The seals I'm using are designed to take advantage of the pressure differential between the two sides while allowing a better "overall" friction coefficient. Getting tighter as the differential increases, but only increasing friction as a result of. As the sub dives deeper, the seals compress against the shaft more due to the greater "sea" pressure against them. Granted friction will increase, but will decrease as you come shallow.

Look at this cross section to see what I mean, and this is WHY the direction of installation is important:


You can see from this installation example how it works:


I'm not sure I understand correctly your "vacuum" ballast.
If to dive you are adding air INTO your water tight compartment from your Ballast tank via an air pump, and then evacuate the WTC into the ballast to surface, this may not work.
You THEN have a condition like an ENGEL Pump boat. Where the internal pressure of the WTC is GREATER than the surrounding water, and they will leak.

Though I never owned an Engel boat using Cup Seals, the Godfather recommended reversing them in those applications.

Understand?

[JWLaRue]

The 'problem' with cup seals being (essentially) omni-directional can be addressed by using a form of o-ring known as an "x-ring"....which has an "X" cross section as implied by the name, meaning it seals in both directions.

That said, my piston boat (OTW Seehund) uses the standard servo linkage boots that are used on a standard OTW dive module. Never tried the x-rings in that application.

-Jeff

[wlambing]

Oh, Jeffy.....,

The correct technical term for the ring you describe as an "x" ring is; "quad-ring", named such for the 4 lobes that form the sealing bits.
There is also a similar beastie know as a "quadradyne-ring" that gets used for somewhat different applications. All lovingly and lavishly explained in the NAVSHIPSTECHMAN Chapt 078.
Quad-rings are great for pushrod, reciprocating type seals. I still have some SubTech shaft seals that will be used in some upcoming projects now languishing downstairs in the pit-o'-doom.
Take care, maybe will see you soon?

B^)

[JWLaRue]

Well, that could be! I just call them by what McMaster-Carr calls them in their catalog.

-Jeff

p.s. I wish I was going to Groton, but I'll be working on a Government opportunity.

[bigdave]

If you are using cup seals in an Engel boat it is best to run the seals back to back.
That is the outside seal (Water side) gets tighter as the water pressure rises.
The inside seal facing the other way gets tighter as the piston puts more pressure in the dry space.
At least that is the way I do it.
Or just use a Simmering like Engel does.
There is a small spring inside the seal that keeps pressure on the shaft.
I have also found never use an X seal (Quad ring) on a motor shaft.
Too much friction and they will die a tragic death.
At least this is from my experience. BD

[jure george]

Hello again

Thanks for the updated drawings and plans. I have to admit I`m a little confused about the above seal discussions.

I plan on using a air pump to pump air from my WTC chamber into the ballast section where an air bag is located to surface, causing low pressure to be in the WTC when diving the air is returned to the WTC and repeat.

From my explanation, will this drive shaft seal work OR what do I have to do to have a safe dry operating unit?

Thanks
George

P.S. Is QuarterMAster o.k with me downloading his paper plans and making a copy for my self of his insertion tool and making his version of the shaft seal?

[QuarterMaster]

Hello again

Thanks for the updated drawings and plans. I have to admit I`m a little confused about the above seal discussions.

I plan on using a air pump to pump air from my WTC chamber into the ballast section where an air bag is located to surface, causing low pressure to be in the WTC when diving the air is returned to the WTC and repeat.

From my explanation, will this drive shaft seal work OR what do I have to do to have a safe dry operating unit?

Thanks
George

P.S. Is QuarterMAster o.k with me downloading his paper plans and making a copy for my self of his insertion tool and making his version of the shaft seal?

George, I'm confused, forget about surfacing...first things first.

Step 1-WHERE does the air go from your airbag when you DIVE??

causing low pressure to be in the WTC when diving the air is returned to the WTC

I don't understand how you can have low pressure in the WTC when air is returned to the WTC.

Correct me on the following:

1-You prep the model, turn it on, close the "hatch".

2-You pump AIR from the WTC into the Air Bladder BEFORE you place it in the water so she FLOATS in her surface condition.

The WTC is now experiencing less pressure (more vacuum) than the air around it because the AIR BAG is full. Pressure outside the hull is greater than the inside.....GOOD, this seal will work as is!

3-You run around on the surface, all smiles feeling good.

4-You commence a dive, release (or pump) the air BACK into your water tight compartment FROM your air bag. Sub goes under.

The WTC is now experiencing pressure equivalent to what it was BEFORE you closed it up, or normal at the surface WHICH IS STILL LESS THAN WATER AROUND IT...GOOD, this seal will STILL work as is!

5-You been running for a while, still all smiles, Diving Officer, surface the boat, Surface....surface ...SURFACE! You pump AIR from the WTC into the Air Bladder.

The WTC is now experiencing less pressure than the air and WATER around it because the AIR BAG is full. Pressure outside the hull is greater than the inside.....GOOD, this seal will STILL work as is!

If that's "what float's your boat" Your good to go as is.

The direction of the cup should always be to the side with GREATER pressure at any moment. Period

Hope this helps

Ed

[QuarterMaster]

Oh, Jeffy.....,

The correct technical term for the ring you describe as an "x" ring is; "quad-ring", named such for the 4 lobes that form the sealing bits.
There is also a similar beastie know as a "quadradyne-ring" that gets used for somewhat different applications. All lovingly and lavishly explained in the NAVSHIPSTECHMAN Chapt 078.
Quad-rings are great for pushrod, reciprocating type seals. I still have some SubTech shaft seals that will be used in some upcoming projects now languishing downstairs in the pit-o'-doom.
Take care, maybe will see you soon?

B^)

Oh COB......

I know you mean these lol!!



Way back when I first experienced shaft leaks in my WTC-3.5, I replaced the Cup seal with these and the resultant friction caused my Speed 500 to heat up so much it scorched the inside of the WTC



I found there a bit too tight even for pushrods. Which lead me down the path to...
1-Water Cooling
2-My "KRICK U25" style seals for linear pushrods.
2-Double cup seal for screw shafts, and
more importantly
3-Bearings outboard of BOTH ends of the screw shaft seal, and the shaft will ALWAYS have floating dogbones on both ends to ride true to the seal. I will never hook it up directly to the motor.

If you are using cup seals in an Engel boat it is best to run the seals back to back.
That is the outside seal (Water side) gets tighter as the water pressure rises.
The inside seal facing the other way gets tighter as the piston puts more pressure in the dry space.
At least that is the way I do it.

I like this, easy enough to do here. Cups face OUTBOARD with the lubricant between! Regardless of pressure direction, one is good to go!

BTW, if anyone cares or has bothered to read this far, always give a your shaft ends a small chamfer so the don't damage the cup seal when inserting it.

[jure george]

Hello again QuarterMaster and gang

Yes your operational steps is exactly what I was thinking but struggle to put into writing. Thank you for your confirmation.

To repeat, it is o.k with you if I were to printout your insertion tool plans? Also could you give the part number for the other seals mentioned after your initial build post? Would it be over kill to use thise seals or just stick with what you have listed?

Could this same seal be made for smaller drive shafts? 1/8"?

George

[QuarterMaster]

Yes your operational steps is exactly what I was thinking but struggle to put into writing. Thank you for your confirmation

It was my pleasure. As I never used the Air bag system I had to work it out in my head anyway. I did not wish to give you false information.
I see now that it WILL work here. Since in BOTH surface and submerged conditions, external pressure is greater.

To repeat, it is o.k with you if I were to printout your insertion tool plans?

Yes of course, be my guest. This is how I give back to a community that gives so much to me.

Also could you give the part number for the other seals mentioned after your initial build post? Would it be over kill to use those seals or just stick with what you have listed?

George, go back to that 3rd post, everything you need for the build is there. These are the seals, NOT alternate or additional parts.
The numbers listed at the END of each line, in bold, IS the Part number for that part for the vendor listed above it.
Select the Vendors name ( McMaster Carr or O-ring Store) which is a link that brings you to their web site. copy and past the BOLD part number of the component you want, enter and VIOLA, your done!

Could this same seal be made for smaller drive shafts? 1/8"?

Yes, just choose the appropriately sized hardware.