Russian Borei Sub Build

[He Who Shall Not Be Named]

I realize I could just eliminate the jet pump system and install a 7 bladed brass prop, and I am sure that would move the sub through the water! But I want to keep the boat in it's original design and just hope that I could get enough movement from the enlarged original design!

I guess my question for those in the know, and based on what you see, would the larger (35.50 mm) jet pump system move the boat through the water? I am not looking for speed at all!

Input appreciated!

Rob
"Firemen can stand the heat"

Go with the scale propulsor. It may look small, but it will move enough water. Don't sweat the small stuff.

Look at how 'small' the wheel is on the Russian KILO. Yet my model -- featuring a scale propeller -- can go quicker than I can control it if I fire-wall the throttle.

https://www.youtube.com/watch?v=W9Pg0zGb5Wo

David

[rwtdiver]

Go with the scale propulsor. It may look small, but it will move enough water. Don't sweat the small stuff.

Look at how 'small' the wheel is on the Russian KILO. Yet my model -- featuring a scale propeller -- can go quicker than I can control it if I fire-wall the throttle.

https://www.youtube.com/watch?v=W9Pg0zGb5Wo

David

Thank you David!

I certainly see what you mean! Great photos and video!

I sure did not want to change the original design of the Borei! Going to move on with the jet pump design! Thanks again for all your help and advice David!!

Rob
"Firemen can stand the heat"

[rwtdiver]

Worked on the stern section today, and finished up the installation of the control surface linkages and the main drive shaft. After checking everything over a second time, I attached the stern section to the main hull!



Tomorrow I will fabricate the hull section tie down assembly , it most likely be a stainless steel or brass bolt!

Rob
"Firemen can stand the heat"

[He Who Shall Not Be Named]

Worked on the stern section today, and finished up the installation of the control surface linkages and the main drive shaft. After checking everything over a second time, I attached the stern section to the main hull!



Tomorrow I will fabricate the hull section tie down assembly , it most likely be a stainless steel or brass bolt!

Rob
"Firemen can stand the heat"

post pictures of that rotor. Front, back, and side -- place a ruler in the shots. I think that thing has way too much blade area for the disc.

It should look a bit like these:







David

[rwtdiver]

David,

I painted the inside of the prop section so that I did not over spray into it. There for the photos will be hard to see!




I basically have the same thing that you are showing! Different design, because of the 3D printed files!

Rob
"Firemen can stand the heat"

[He Who Shall Not Be Named]

Developed blade area should be 60-75% of the disc, less the hub. The one you have is about 110%. Pitch should be close to diameter. (Pitch is the distance the screw advances in one rotation with no slip -- pitch is NOT an angular measurement!).

Your rotor is USLESS!

Might make a good food-blender though.

Either remove some of the blade area of what you have or re-CAD the rotor to follow the above rule.



David

[rwtdiver]

Developed blade area should be 60-75% of the disc, less the hub. The one you have is about 110%. Pitch should be close to diameter. (Pitch is the distance the screw advances in one rotation with no slip -- pitch is NOT an angular measurement!).

Your rotor is USLESS!

Might make a good food-blender though.

Either remove some of the blade area of what you have or re-CAD the rotor to follow the above rule.



David

David,

Thank you very much for the information! Here are two better photos of the 3D printed props. To clarify, I did enlarge the actual prop itself from 27 mm to 33 mm, but the design is the same as original!

This is basically the same prop set up that I have on the Astute, and it did very well!?





In order to make the changes to a new prop design I will have to fabricate a new stern section, because the current system is all glued in place!

I may just run what I have and see what happens before I go through all that!

Thanks again David for the input, it's always appreciated!

Rob
"Firemen can stand the heat"

[He Who Shall Not Be Named]

So, the ASTUTE had a rotor blade area this large? And it worked fine?

I stand corrected.

David

[rwtdiver]

So, the ASTUTE had a rotor blade area this large? And it worked fine?

I stand corrected.

David

David,

The Astute that I built was a 3D printed boat! Scaled down version of the full scale of course! The photos show how the pump jet system looked on that boat. Different design, but with some of the same design principals as per say!





I do not even come close to understanding the principals involved in submarine prop or jet pump system designs! This was the files I purchased from Bob (Nautilus Drydocks) and that is what I went with. And on the Astute it worked ok for me! I am sure that if my boats even make the slightest movement in the water, that's a success for me!

I am so new at this hobby and still at the bottom line learning stage! My stuff is pathetic compared to what you and others do on this forum.

I guess bottom line for me is, if it floats, moves with some sort of realism, and looks some what like a submarine! That's ok with me. But I will say! As I pursue this wonderful hobby with my "Tinker Toys" If I can continue to keep learning more and more with each build! Then I guess I am heading in the right direction! And David, that is why I hang on every photo you post and every word you speak to try and make sense of how these machines work!

I thank you for taking the time to help push this beat up mortal in the right direction!

Rob
"Firemen can stand the heat"

David I took the prop system out and have a better photo as to what it looks like!





If I understand you correctly!? I can remove some material from the back side of the blade to allow more water to flow over the blades!?

Thanks for the help David!

Rob
"Firemen can stand the heat

[rwtdiver]

It seems I can't get nothing right!!!

Rob
"Firemen can stand the heat"

[He Who Shall Not Be Named]

David,

The Astute that I built was a 3D printed boat! Scaled down version of the full scale of course! The photos show how the pump jet system looked on that boat. Different design, but with some of the same design principals as per say!





I do not even come close to understanding the principals involved in submarine prop or jet pump system designs! This was the files I purchased from Bob (Nautilus Drydocks) and that is what I went with. And on the Astute it worked ok for me! I am sure that if my boats even make the slightest movement in the water, that's a success for me!

I am so new at this hobby and still at the bottom line learning stage! My stuff is pathetic compared to what you and others do on this forum.

I guess bottom line for me is, if it floats, moves with some sort of realism, and looks some what like a submarine! That's ok with me. But I will say! As I pursue this wonderful hobby with my "Tinker Toys" If I can continue to keep learning more and more with each build! Then I guess I am heading in the right direction! And David, that is why I hang on every photo you post and every word you speak to try and make sense of how these machines work!

I thank you for taking the time to help push this beat up mortal in the right direction!

Rob
"Firemen can stand the heat"

David I took the prop system out and have a better photo as to what it looks like!





If I understand you correctly!? I can remove some material from the back side of the blade to allow more water to flow over the blades!?

Thanks for the help David!

Rob
"Firemen can stand the heat

No. Don't reduce the thickness of the blades. Reduce the cord of the blades. Eliminate about 25% of cord from the trailing edge for each blade -- then file and sand to present the curved portion of each blade on the suction/back side (the forward side of the rotor blades).



David

[rwtdiver]

No. Don't reduce the thickness of the blades. Reduce the cord of the blades. Eliminate about 25% of cord from the trailing edge for each blade -- then file and sand to present the curved portion of each blade on the suction/back side (the forward side of the rotor blades).



David

Thank David!

Tried to cut the prop blades and shape, and to no avail! There for I am in the process of designing my own and printing! I will keep you posted! Going to get this come Hell or High water!

Rob
"Firemen can stand the heat"

[He Who Shall Not Be Named]

You'll get there, Rob. Keep swinging!

[rwtdiver]

You'll get there, Rob. Keep swinging!

David,

Do either one of these two hold any promise!?



The photo below shows A and B with the original prop on top!



I think A might be the best to go with!?

Rob
"Firemen can stand the heat"

[He Who Shall Not Be Named]

Go with 'B'.

'A' has way too much pitch.

David