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Author Topic: Caldercraft 'Northlight' Puffer  (Read 2252 times)

Nemo

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Caldercraft 'Northlight' Puffer
« on: January 06, 2017, 08:04:43 pm »

I have started restoring an elderly and very neglected 'Northlight'( Now 'Jennie') and was hoping that the many builders of this great wee boat can help me with a few queries.
 
1. What is the recommended motor size?
2. The battery space  appears to be the size of a 6v 4.5ah SLA type, would this be correct?
3. The ship needs complete ballasting, what would be the recommended weight I require for this?

Thanks in advance.
Bob.
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unbuiltnautilus

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Re: Caldercraft 'Northlight' Puffer
« Reply #1 on: January 07, 2017, 01:00:05 pm »

MFA or similar RS385 motor, or a Monoperm if you have one. It will also fit a 6v 8 amp or 10 amp battery. Less ballast then needed. Although a seat and a flask of tea may help, as you will be at the lake all day long :}
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Buccaneer

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Re: Caldercraft 'Northlight' Puffer
« Reply #2 on: January 07, 2017, 02:34:52 pm »

Hello Bob
I have scaled down the figures from my Mountfleet Models 'Highlander' Puffer and reckon you will be looking at about 4.5-5 Kg. At 4.5 it may be a bit high in the water and the wind will catch it as well. Hope this helps.

John
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Corposant

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Re: Caldercraft 'Northlight' Puffer
« Reply #3 on: January 08, 2017, 04:03:59 pm »

 Hi Bob
I doubt whether the following will be of use to you – but I've had a rummage through my notes.
(Aghast at how long it's taking me to build my Northlight!)
The motor I used was salvaged from a piece of discarded equipment. It is a Mabuchi 385.
Nominal voltage 12V (6 – 18V)    max. efficiency drawing 0.837 amps – c. 9000 rpm
(So I concur with Unbuiltnautilus!)
As I was planning to aim for “scale speed”, I used a 6V battery pack. (3700 mAH NiMH 5 cell).
If I were starting again, I would choose a SLA!
I did some testing on current draw:
7.5V   1.4A   (stalled)
9.5V   1.8A         “
           Free running  Stalled
5.29V    230mA            940mA
7.45V    250mA            1.3A
9.39V    270mA            1.7A
12.9V    310mA            >2A

 
I have always been a bit mind-boggled at models needing a 20 or 30 A ESC! At the time, I wondered if the Puffer would move at all.
The video shows the result (taken at Wicksteed last May).

(The sound generator was not in my model!)

 
My initial guestimate for ballast was c. 1.5 Kg. I cut two pieces of lead 115mm long x 19mm wide x 22mm high to mount each side of the battery pack and two further pieces 50mm long. The total weight was 1452g.

 
The weight of the white metal fittings, batteries etc. was well over 800g and initial waterline testing resulted in the removal of one of the smaller pieces of lead (220g) Since then, I have always been trying to keep the weight of the fittings down (plastic oil-drum, wooden stern grating, copied crew in resin etc.).
These pics show the general arrangement:
http://s949.photobucket.com/user/photomultiplier/media/DSC01590.jpg.html][/URL]
http://s949.photobucket.com/user/photomultiplier/media/DSC01625.jpg.html][/URL]
http://s949.photobucket.com/user/photomultiplier/media/DSC02637_zpsqaegt9qg.jpg.html][/URL]

 
The total weight of my Northlight is just under 5 Kg, so I think John's estimate of  4.5 – 5 Kg is a bit on the generous side for 1:32 – but you don't say what you still have on board in the way of fittings.

 
Regards,
Mike

 
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Nemo

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Re: Caldercraft 'Northlight' Puffer
« Reply #4 on: January 10, 2017, 09:38:24 pm »

Many thanks to all for replies and helpful advice. The boat as it came had no battery and a only couple of odd unmatched bits of lead lying in the hull. The boat is the standard Northlight as it is supplied and the only addition I have made is a smoke generator in the aft end (tight squeeze!) of the hull. With a (guessed) 6vSLA on the 'platform' it rode very high without any additional ballast and was very 'tender' as would be expected. Now I have an idea of the all-up finished weight, I hope to calculate the weight of ballast required to get her down to water level and stable. The motor fitted is not working and I now have an idea for a replacement.
Unlike Mike's immaculate construction, this old thing is what one might called scruffy and that is how I remember Puffers as I watched many on the Clyde in my youth.The finished item, I hope will reflect this memory. I have spent some hours cleaning her up a bit (but not too much!) and found she is quite a nice boat.
Thanks again chaps - I now have something to go on :-))
*'JENNIE' was the name of one of the Puffers my Dad worked on.
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Nemo

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Re: Caldercraft 'Northlight' Puffer
« Reply #5 on: January 10, 2017, 10:03:38 pm »

Mike, I would add that, having seen the real thing many times on the water, your video shows how well she performs and looks and runs  exactly how a Puffer should. Well done!
Bob.
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Corposant

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Re: Caldercraft 'Northlight' Puffer
« Reply #6 on: January 10, 2017, 10:45:10 pm »

Thanks for posting the pictures of "Jennie" - she has great potential!

I'm a bit worried you think mine is "immaculate"  :o as I've spent a lot of time recently trying to get the weathering right! (The stills in my post are from c. 2012.)

I am, however, greatly encouraged by your comments about her appearnce on the water.  :-)

We look forward to pics of Jennie's progress - your Dad would be tickled!

Mike
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