Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: rnli12 on September 28, 2012, 08:51:28 pm

Title: Unknown make of Submarine hull 'Los Angeles'
Post by: rnli12 on September 28, 2012, 08:51:28 pm

Hi all,

I have a unknown make of 'Los Angeles class' measures 45" x 6" x 6" hull fitted out with water/air tank system, it runs on a 12v battery with 540 motor driving a 55mm 7 blades propeller. Any ideas if the motor/prop combination is to much seems very nippy. Looking to overhaul the boat slowly.

Any other advice grateful received.

Rich

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: U-33 on September 28, 2012, 09:26:26 pm

Can we have some pictures, please?

Rich

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: Subculture on September 28, 2012, 09:49:11 pm

Depends on the wind on the 500 type motor. One with a lot of turns can pull a prop that size direct drive, and assuming the pitch is no greater than the diameter (e.g. 1:1 or thereabouts) similar powertrain is fitted to the Engel Lafayette, and that nips along too- streamlined hull form.

Generally for a prop that size you shoud be looking at a prop speed of between 2000-500RPM, depending on prop pitch, speed you want, and running time. There are only a two or three companies I know of that make scimitar props, one is Raboesch, another is Prop Shop and I think George Sitek makes them too. Raboesch are pretty much all 1:1 or 1:1.1 pitch to diamter ratio. Prop Shop tend to be higher in pitch, so you usually need to dial the RPm down a bit. Don't know about Sitek props, never owned one.

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: essex2visuvesi on September 28, 2012, 10:26:57 pm

Carson toxic 540 can motor sounds a good bet... 6200rpm@7.2V

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: rnli12 on September 29, 2012, 08:47:09 am

Hi,

Thanks for the responses, I have attached some photos of the model, its a direct drive 540, with a homemade prop but I have seen a seven blade 55mm on CMB 55mm M4 Threaded 7 Blade R/H Brass B-Type Propeller or L/H.

i guess the scale is around 1/96 or 1/72?

Thanks for you support.

Rich

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: U-33 on September 29, 2012, 09:12:56 am

Looks like an MMB LA to me http://www.marksmodelbits.co.uk/ (http://www.marksmodelbits.co.uk/) Strange internal layout though, I'd have expected to see a cylinder in there, that's how I built mine. Scale is around 1/80th....ish.


(http://s12.postimage.org/lj6lpabm1/p2407110.jpg) (http://postimage.org/image/lj6lpabm1/)

Mine had an ACTion 550 motor, direct drive, to a 60mm seven blade scimitar prop...if I remember rightly I got it from Deans Marine, so it was probably a Raboesch one.

Rich

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: rnli12 on September 29, 2012, 09:55:35 am

Rich,

I now realised I have seen the model before at MMB! Your layout seems much neater have you got any details of what you have used and where from please? Is your a direct drive with a 60mm prop?

Think I will change the motor soon a go to a 60 mm prop.

Regards,

Rich

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: U-33 on September 29, 2012, 10:02:16 am

Hi Rich,

My cylinder is an IDIDIT...if you pop over to http://www.theassociationofmodelsubmariners.com/t200-la-class-semi-kit (http://www.theassociationofmodelsubmariners.com/t200-la-class-semi-kit) you'll find my build log of the boat, save me repeating it all on here.

Rich

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: rnli12 on September 29, 2012, 10:07:33 am

Many thanks Rich

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: U-33 on September 29, 2012, 10:10:05 am

My pleasure Rich...


Rich

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: Marks Model Bits on September 29, 2012, 10:15:02 am

It definitely isn't one of mine...... The bow, stern, hull/deck split is different & it is 8" too short as well.....

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: rnli12 on September 29, 2012, 10:24:35 am

Mark,

I was just thinking that may drop you a pm next week when I get my head around this one!

Rich

Title: Re: Unknown make of Submarine hull 'Los Angeles'
Post by: Subculture on September 29, 2012, 12:05:54 pm

It could well be a scratchbuilt hull. LA class is a farily straightforward shape, being largely cylindrical with taped bow and stern, so it suits construction from PVC pipe, with grp nose and stern.

Be careful going too large with a single prop, this moves the torque lower down, which is more efficient, but can roll the boat over under power.