Pump Jet Kilo

[bigdave]

I just wanted to show a few photos of a quick side project I have been working on. First I want to thank Wayne Frey, without his help I would never have been able to do the conversion.
What I did was convert my Trumpeter Kilo kit to the Alrosa pump-jet sub. It is not 100% scale but as close as I could come using only photos.
Not all the views were available either. But I am grateful for all the photos Wayne was able to provide. An interesting point is Wayne is the only one that will know how close I came to getting it right, as his photos were for my eyes only. They will be used in his new book so you guys will have to wait till then.
The pump is not a static unit and is functional. It took a bit of cutting and filing to convert the Trumpeter kit. The little impeller inside is only about ¾”. I have only tested the pump in the laundry tub so far so I am not sure how good it will move the sub. I will report on it’s first test dive once I get the cylinder back in. Thanks again Wayne. BD.

[redboat219]

Great little side-project there Dave.

Great little side-project there Dave. Wonder how she'll perform with a PJ. Does it have a stator assembly inside? BTW, I notice that the stern planes are different from your standard Kilo, they lack the fillet where the leading edge joins the hull.

[bigdave]

The rear surfaces are very

The rear surfaces are very different on the PJ Kilo. It took a lot of modification to change the Trumpeter kit. I do have flow correctors before and after the impeller. Well I tested the sub in the pool today and the PJ is a bust. . It worked, but the thrust was not enough to propel the boat very well.
I will see if I can get it apart and try for a redesign someday. O well!! It looks cool anyway.
My friend kept saying, "Give it full speed,” I said, "It is full speed" A slight chuckle was heard. . BD.

[redboat219]

Sorry to hear about the

Sorry to hear about the PJ failure:cry:
I think you're getting insufficient inflow to the PJ due to the narrow intake.

[bigdave]

Well, I had a few

Well, I had a few minutes of free time and decided to stop staring at the Kilo sitting on the shelf and try and do some PJ mods.
#1- Open up the intake so more water can flow in.
#2- Increase the size of the impeller. (I can only go 1/8" larger in Dia).
#3- Add the extra piece to the exhaust of the PJ for scale, and maybe to increase flow speed.
I will let you know how I make out. BD.

[bigdave]

Well I tried three things

Well I tried three things and my thrust is much better. Without a total redesign it is probably the best I can do. I have not run it under power yet, but placed the rear end in water.
I opened up the intake, put a bit more pitch in the impeller, and added the extended nozzle.
Once I get her in the water under power I will report on these changes. BD.

[redboat219]

PJ Mods

How did the PJ mods turn out Dave?

[lociz]

Nice work BigDave. http://www.subcommittee.com/forum/icon_eek.gif


Nice work BigDave.
Just a few comments from me based on pictures I have of the Alrosa. I dont think the stern planes on your model are correctly placed, should be further back on the pumpjet. But i guess the modernisation would be to big and difficult to achive. Your Alrosa pumpjet also seems to be a bit short. I am amazed everytime I look at the Alrosa pictures how long and big that pumpjet-section realy is. Do you/Wayne have the exact length/with of the pumpjet-section?
Also on a picture i have here, there is a rather big "bulb" (dont know what else to call it) in the center aft of the pump-jet. Like an vortex attenuator but bigger, completely round and with a hole in the center. I am sorry i cant post the picture here as I think it is copyrighted, but it shows a rather closeup of the pumpjet fully assembled on the Kilo.

Sorry if my english are bad...

[bigdave]

Thanks,
There were no real

Thanks,
There were no real full on side view shots that I had. It was hard to tell exactly how long it was. The part on the rear output I did not add. I made the outlet larger than scale so it would flow more water. I have not had a chance to run the boat yet except in the tub so I am not sure how much speed I can get after the update. It does push much more water out the pump now. BD.

[wayne frey]

The "bulb" design is to

The "bulb" design is to collapse the trailing air bubbles to help quiet the boat.

[bigdave]

I hope to be finally

I hope to be finally testing the PJ soon Wayne. BD.

[bigdave]

Here is a short video

Here is a short video of the Alrosa running at the YMCA. The video makes it look like it is moving faster than it really is. I believe I have figured out how to improve the performance. BD.

I will post video soon. Hint Watch the bottom of the video or you will miss the sub.

[pirate]

Dave,
Where's the sub in the

Dave,
Where's the sub in the video? I think you need a better aimer on the camera. I thought I saw some periscopes go buy for a second, but I'm not sure.

Pete

[pirate]

Dave,
Is there any way you

Dave,
Is there any way you can show us what the propulsor itself looks like apart from the shroud?

Pete

[bigdave]

Hi Pete,
Watch the bottom

Hi Pete,
Watch the bottom of the video. You can see it coming on the surface of the water. It was not the best video.
I would fire Steamboy but he works cheap!!
I am going to pull the shroud off and redesign the impeller and will get some photos of how it looks now.
It's still not right.
Trying to keep it scale looking and making it operate well is proving to be challenging. I think it is the two stage design that makes it funnel down to a small output that is killing my efficiency. But I am just learning. BD.