Topic: Engine (Read 4828 times)

Mansfield_Marauder · « **on:** January 07, 2008, 07:27:37 pm »

Can anyone advise me what size engine I would need to move a boat of 120 cm LOA and 18cm Beam at a scale speed of 4MPH? and can they let me have the overall dimensions so I can fit it into my design?

grasshopper · « **Reply #1 on:** January 07, 2008, 07:40:02 pm »

We'd be glad to help but we'll need more information than just the overall dimensions

Mansfield_Marauder · « **Reply #2 on:** January 07, 2008, 08:19:46 pm »

Not sure what other information you need it is going to be made of ply not sure what thickness yet, and if everything goes according to plan it will be a model narrow boat hence the requirement for a scale speed of 4mph also should I use IC or Electric IC will be better on the batteries. ???

barryfoote · « **Reply #3 on:** January 07, 2008, 08:32:30 pm »

IC on a narrow boat....Not if you want to keep it on this planet. There are so many variables before dcioding on which motor to use.i.e. weight, draft, speed control system. Suggest you contact FLJ (fullmetaljacket) on this site. He will give you some good advise.

Bryan Young · « **Reply #4 on:** January 07, 2008, 10:04:56 pm »

This answer may sound a little trite, but it is meant seriously.
If you can, then I suggest you overpower the boat. Speed can always be controlled via the ESC. I always "overpower" for simple reasons. 1): I can accelerate out of trouble when some muppet is in danger of ramming me. 2): With a heavy model it is nice to have a certain amount of astern power available when unexpectedly required.
With my "heavier" (110lb+) I usually plod along at about scale speed, but if I see trouble approaching it can be useful to go from a scale speed of 12 knots to 50 knots! This facility has saved me many hours of repairing things. The same with going astern. Inertia is the name of the game here. A boat (model or otherwise) doesn't need an awful lot of power to keep it going once it's on the move. Stopping it is another thing. Power. There is no reason whatsoever to drive your model with the controls at max.
Isn't that what ESC's are for anyway?

sinjon · « **Reply #5 on:** January 07, 2008, 10:07:42 pm »

Be very very careful Barry.

FLJ - LEATHER not METAL.

I made the same mistake once and hid for three days.

Colin

FullLeatherJacket · « **Reply #6 on:** January 07, 2008, 11:44:44 pm »

Colin
Many, many thanks for your vote of confidence, although I can't imagine why you think I'm at all fierce............. :angel:

Footski
That's your one life, mate! Place that order by Friday and we'll drop it over the side on Saturday on the way to Puertopolensa (Ole!!)

M_M
Like Edward and Tubbs, you sound "local". We're NG3. Coffee's on most of the time if you want to call in. The bullsh1t comes for free.

FLJ

OMK · « **Reply #7 on:** January 08, 2008, 06:49:34 am »

Mansfield Marauder?? Man, what a neat handle.
Bung a 10CC 4-stroke in there -- you'll be alright. Marauders do it in boats, eh?

OMK · « **Reply #8 on:** January 08, 2008, 07:10:27 am »

Hehee!... No offence, amigo. It's just that when I read the bit where it says tiny boat, and IC engine....... Heheeeeee.

Either you got balls, or you've been drinking too much of that free NG3 coffee.

barryfoote · « **Reply #9 on:** January 08, 2008, 07:36:59 am »

Quote from: sinjon on January 07, 2008, 10:07:42 pm

Be very very careful Barry.

FLJ - LEATHER not METAL.

I made the same mistake once and hid for three days.

Colin

Thanks for the advise Colin.....Whata mistaka to maka. Looks like it will cost me money...

barryfoote · « **Reply #10 on:** January 08, 2008, 07:39:01 am »

Quote from: FullLeatherJacket on January 07, 2008, 11:44:44 pm

Colin
Many, many thanks for your vote of confidence, although I can't imagine why you think I'm at all fierce............. :angel:

Footski
That's your one life, mate! Place that order by Friday and we'll drop it over the side on Saturday on the way to Puertopolensa (Ole!!)

M_M
Like Edward and Tubbs, you sound "local". We're NG3. Coffee's on most of the time if you want to call in. The bullsh1t comes for free.

FLJ

So humbly sorry FLJ.....I would try and blame a typing error, but don't think you will go for that......Okay looks like the order will be placed but won't be this week...Hopefully next...

I was only trying to get you some trade.....honest

Mansfield_Marauder · « **Reply #11 on:** January 08, 2008, 02:41:26 pm »

Right here goes then based on a design for a narrow boat i have seen on the web
LOA 192 cm, Beam 18.2 cm, draught 7cm, wieght .22Kg so do I need IC or Electric I still prefer IC and think getting one small enough should not be a problem though I think the comments about over powering mentioned above are quite valid and I think overpowering for emergencies a good idea. ???

banjo · « **Reply #12 on:** January 08, 2008, 02:54:52 pm »

Mansfield_Marauder

Aside from all the good advice given above, if you go the IC route, as you appear determined to do, then you do realise the restrictions that apply to the use of IC powered boats?

Didn't you?

Check with your intended venue....

barryfoote · « **Reply #13 on:** January 08, 2008, 03:23:21 pm »

Come on guys we have to try to persude MM away from Ic. Does he really want a tiny, screaming engine in a boat meant for gentle trips on the river?

Tell him as it is!!

Barry

dreadnought72 · « **Reply #14 on:** January 08, 2008, 03:34:07 pm »

Well...in MM's favour I like the idea of an appropriate power supply in a model - diesel for diesel, for example. I wish I could steam-turbine my Dreadnought, but it's not going to happen.

But looking at Enya's smallest engines, there's an "11" which produces 0.40BHP - around 300W. Way overpowered.
Its power band starts around 7000 rpm, so it'd need gearing down - but you'd never be able to muffle that 7kHz whine going on.
It costs around £90 - which would be getting you all the electrical bits you need, with change for a beer or two.

I wouldn't say "don't do it", but I wouldn't do it myself.

Andy

Colin H · « **Reply #15 on:** January 08, 2008, 03:56:51 pm »

One problem in the Notts area from what little I know is the lack of venue's where you can use I.C. in fact I can only think of one.

One more point there are now many 1:1 narrow boats powered by electric, if memory serves all the hire boats on the Monmouth canal are so powered.

Colin H.

Mansfield_Marauder · « **Reply #16 on:** January 08, 2008, 07:53:29 pm »

OK so what is the most appropriate electric engine (I know some one who is fitting car windscreen washer engines in his tug) my worry with electric is that I have a bought hover craft and the battery last about 15 mins I know it is powering the lift motor to get itself off the ground but will electric in a bout last much longer because I do not fancy carting the boat and everything to Kingsmill to spend 15 mins on the water to pack up and go home again. :-\

FullLeatherJacket · « **Reply #17 on:** January 08, 2008, 08:36:49 pm »

M_M

Your reservations are groundless, you'll be pleased to hear. It's not a valid exercise to compare a model hovercraft with a narrow-boat; to do so would be like trying to equate the power requirements of a Ferrari to those of a quarry tipper-truck.

If we can ignore (as a typo) the decimal point in front of your quoted displacement, then what you have is a model about six feet long and seven inches wide. It is a slow-moving displacement hull and so needs minimal power to maintain a forward speed; although you need a bit of oomph to get it moving and also to stop it.

I would suggest starting with something like a Graupner Speed 720 Torque motor, running on a 12 volt supply, with a 70mm 4-blade propellor - although I've plenty of scope for being corrected about that last bit. This motor draws something around 2 Amps under normal operations, and you have ample room for a sealed lead acid battery with a capacity in excess of 10 AH. This means that with a fully-charged battery you will obtain around five hours' running (put simply) before you need to go home and recharge the battery. It's quite possible that you could fit two or even more such batteries, which would effectively increase your sailing time pro-rata. I know Kings Mill Reservoir and I wouldn't want to be there overnight!

If you're serious about this then I would suggest you buy a book on the subject and gen up on the basics. Both Traplet and what-used-to-be Nexus Publications produce decent tomes.

Good luck!

FLJ

Colin H · « **Reply #18 on:** January 08, 2008, 09:27:25 pm »

M.M.

Only been in this game 3 or 4 years myself and found Scale Model Ship Propulsion By Tom Gormann (ISBN 1 86176 2100 very very helpful. You could always ask your local library to get it in for you.

Yours Colin H.

Mansfield_Marauder · « **Reply #19 on:** January 09, 2008, 07:56:34 am »

YeahI realised after I put the figures in that a scaled down wieght was irrelevant the actual wieght of the completed full size boat is 22 tons I did a conversion to KG and it appears that the converter I used assumed I meant meteric tons because the conversion came out at 22000 kg which I just scaled down which as I have just mentioned is totaly irrelevant as the model will need to be wieghted down so that it sits on the correct water line and with a couple of lead batteries in there I am hoping I will not need too much ballast. Thanks everyone for there help. The project will take a while as funds are tight and I am still in the design stage. If anyone wants to look at the actual boat goto www.theantidote.info[/font]

Colin H · « **Reply #20 on:** January 09, 2008, 04:08:12 pm »

M.M.

Great looking boat and the fit out is smashing, best use of 63` I have seen in a long time.

Yours in envy Colin H.

funtimefrankie · « **Reply #21 on:** January 10, 2008, 11:04:24 am »

You could go for one of these...
ebay no 300187431261

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Author Topic: Engine (Read 4828 times)

Mansfield_Marauder

Mansfield_Marauder

barryfoote

FullLeatherJacket

OMK

OMK

barryfoote

barryfoote

Mansfield_Marauder

banjo

barryfoote

Mansfield_Marauder

FullLeatherJacket

Mansfield_Marauder