Building the french suffren sna

[Albacore 569]

New revised rudder form.

[Albacore 569]

Gradually agonizingly beginning to make successful part prints from Printer. This morning, the new rudder shapes all printed, sliced 8 on plate with only 1 having a small deformity. was sliced in different angles to experiment to see if some angles are better than others. Will try again with other small parts now. Bow planes and bow plane door cover openings next. Parts now getting their UV sun tans (45 minutes).

Maybe I can make that bomb bounce on the water like a ping pong ball after all?

[Albacore 569]

Two in a row? Maybe the FEP now matt side up fixed the issue

[Albacore 569]

New Suffren impeller. Resin takes primer paint well...balances great, crisp printing. 4 months frustration then dare I say it's finally working?..lol 15 blades right-handed prop. Diameter 6 CM. 1/64 scale model

[Subculture]

I’m going to speculate that the prop shape is a best guess, is there a reason for the overlap of the blades?

[Albacore 569]

Yes Bob. Randy Sander's guess.

I asked Randy to reduce the number of blades from 18 to 15. If you Subculture are bob Martin? Randy remembered feedback from Bob Martin that 18 bladed was too many blades for the water, and that 15 worked better. I requested the number of blades be a odd number. The only 'more definitive' information is a drawing given to me ages ago by hand of a Trafalgar class pump jet general illustration. The blade shapes are different. - broader chord at the base which makes scientific good sense rotational speeds are faster at the tips if the goal is a uniformity of thrust flow along with blade twist. One important thing is making the clearance at the blade tips with the shroud as close a possible with free model prop movement. one EB worker retired now said the clearance on the real pump jet was only a Pencil width.

There is a point though where it is best to blur what a real PJ on a model might look like - for the sake of security and the crews on the subs. So I am happy just with a 'Guess'. as long as it represents the model fine and it operates in the pond water well.

My question is now what color to paint it? The default may be to paint it a gold bronze. But are they? I read in 21st century submarine design they were thinking of Carbon composite blades for pump jets. So do I paint them a gloss black?

Below is one influential image in my considerations what a guess might be.

[Subculture]

I'm not Bob Martin, I'm Andy.

This was a quick and dirty filament print I did for my best guess of a Vanguard propulsor.

[He Who Shall Not Be Named]

I'm not Bob Martin, I'm Andy.

This was a quick and dirty filament print I did for my best guess of a Vanguard propulsor.

... and my best guess as to what the VANGUARD propulsor looked like:

[Albacore 569]

Oh these ****ing contests...lol. See the photos above, that's how it's done folks.

[Subculture]

I’m not in a competition, I just like to play around with these things out of interest. Someone in a position to know what the real ones look like said that he considered the original Prop Shop item was closer to the truth. With a few hints on what could be done to improve the authenticity of the Prop Shop item I drew a cad file and printed a test item. It moved water well enough, but would really need to do some thrust tests to see how it stacks up against the others.

I guess someday I might get to see an original if/when they get declassified, assuming I live long enough.

[trout]

I made a for my Trafalgar pump jet, when printed it with what I thought was the correct number of blades. It push water however it was less than impressed by it. So, I modified by reducing the number of blades and very scientifically tested that (by attaching it to a drill and running it in a kiddy pool). It has a lot more push. It may even run better with fewer blades, but I can always do that later.

[Subculture]

Propulsor/pumpjets typically use prime number for blade counts to avoid harmonics, so typically 11,13,17 etc.

[Albacore 569]

I wrote all that here above in my earlier post.

An odd or Prime number for blade count.

For the model, fewer the blades the better the model pump jet performs in the pond. (Bob Martins observations
and recommendations I am sure are correct). Trout's noting the fewer blades the better the thrust supports Martins too. .

In my illustration of supposedly a Trafalgar pump jet the blade pitch is much too feathered in pitch in my opinion.
In such complex devices, the blade pitch I am sure can be adjusted in dry dock.
So, suspect that illustration does not represent the actual blade pitch and maybe closer in reality to a
conventional blade pitch like in the models posted above. (flatter pitch)

My Suffren's pump jet has to be a post swirl Pump jet, the fixed stators behind the rotating section. Due to
the pivoting ability (Yaw only) of my pump jet to test model maneuverability.
I am sure the Suffren and other French, American and British Russian pump jets are pre swirl for robustness and resistance
to battle damage.

It is less efficient than a post swirl, but on a nuclear submarine the endurance of the power source
(nuclear propulsion) pre swirl is not an issue, But pre swirl is quieter which is the whole reason for the exercise) so all go
I am sure with pre-swirl or possible pre-swirl / post-swirl (both).

For my test, the mechanically simplest way for a yaw pivoting PJ is to make it post swirl. That part of the model
will not be 'scale'. but since that whole thing is classified any way, what is scale in the first place. lol.










he model will not be 'scale'

[Subculture]

15 blades is an odd number, but not a prime number.

[Albacore 569]

Suffering Suffren. Figured out why my prints never seemed to work. My LCD screen is broken or damaged.
In email correspondence with Any Cubic support. Trying to get AnyCubic to replace my LCD screen for all the trouble I have been having.