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[rnli12]

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

[U-33]

Can we have some pictures, please?

Rich

[Subculture]

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.

[essex2visuvesi]

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

[rnli12]

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

[U-33]

Looks like an MMB LA to me 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.




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

[rnli12]

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

[U-33]

Hi Rich,

My cylinder is an IDIDIT...if you pop over to 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

[rnli12]

Many thanks Rich

[U-33]

My pleasure Rich...


Rich

[Marks Model Bits]

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

[rnli12]

Mark,

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

Rich

[Subculture]

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.