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Author Topic: Engine Query From Another Newbee  (Read 1242 times)

Baz2

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Engine Query From Another Newbee
« on: August 23, 2009, 01:17:50 PM »


   Hi all
    I am fairly new to boat building but I have ,dare I mention it, built a Slo-Mo-Shun, yet to see the water.

    I have been following Ramon's Atlas van Lines hydro build, and was thinking of having a go at building one myself. The plan shows an electric motor but how do you decide
    what size of I C glo engine to use?, is there a formula or is it just boating experience/know'how.

    The Atlas van Lines is a 42" X 21" hydro and I was wondering what range of I C glo engines would be suitable. I don't wont to break the world speed record
    but would like a good speed.

    Ramon is using an OPS 60 but I am not sure where this would come in the the range of engines suitable for this size hydro.

       Any advice would be much appreciated.

                           Thanks Baz
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Ramon

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Re: Engine Query From Another Newbee
« Reply #1 on: August 23, 2009, 02:29:43 PM »

Baz - Hi

For what it's worth  - I came by the OPS 60 by chance - when I found the Astec site and the free drawings I just felt that this would be a good combination based on what I wanted to do thirty years and more ago.

It would appear that this size of boat is very popular in the States and the class -1/8 scale hydros - recognises a max capacity of a '67'

Martin (Mayhems 'Mr Fid') has the same scale Circus Circus in which he has an OPS90. That's still as yet really untested as he has had radio problems but previously he put a CMB 90 in a same scale 'Winston Eagle'. That did not apparently last long before going airborne and doing  a fair bit of damage. In my limited (very) experience I would say that this scale would be well overpowered with a motor of this size for good average boating. It seems to me that going for max power has to be balanced with the ability of the craft to stay on the water - well at least most of the time.

If it's built reasonably light any good 60 should be more than sufficient for a good speed - you pays yer money etc.

Do you have any specific type in mind? ie side or rear exhaust, conventional or tuned pipe etc. Rear exhaust is probably better as there is not a lot of sideways room but with the right manifold it could be done with a side mounting. Bear in mind the fuel tank problem ie not much room for anything large.

I have without doubt made a few technical errors during building - if you would like any input please ask or send a PM Glad to help any way I can.

It's really great that you feel inspired to do like wise. My Huntsman is near finished so I will be able to get back onto the AvL fairly soon.

Hope this helps if not just shout.

Now... How about a bit more on that Slo-Mo-Shun :-))

Regards - Ramon

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Baz2

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Re: Engine Query From Another Newbee
« Reply #2 on: August 25, 2009, 08:24:51 PM »


   Hi Ramon

  Thanks for your reply.

  You have given me more things to think about before I take the plunge.

   I would post a picture of the Slo-Mo-Shun but not sure how to go about it.

     Thanks again

             Baz
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BJ

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Re: Engine Query From Another Newbee
« Reply #3 on: August 26, 2009, 11:17:26 AM »

   The plan shows an electric motor but how do you decide what size of I C glo engine to use?, is there a formula or is it just boating experience/know'how. 

For what it is worth  - compare the old (1990's) Prop shop guide on electric motors versus hull size and type on page 1 and compare to engine size/use/type on page 2.

I hope this helps you.
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Baz2

  • Guest
Re: Engine Query From Another Newbee
« Reply #4 on: August 30, 2009, 04:21:38 PM »


   Hi BJ

         Thanks for the info, it will be very useful.

            Baz
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