Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Does anyone recommend using a fan with a 12v Graupner smoke unit?  (Read 2348 times)

Voyager

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 820
Does anyone recommend using a fan with a 12v Graupner smoke unit?
« on: September 24, 2007, 04:48:54 PM »

I have a small micro fan that i purchased a while back, just didn't know if it would be worth fitting it under a 12v Graupner smoke unit for a better smoke effect? Has anyone tried this?

Voyager
Logged

bogstandard

  • Guest
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #1 on: September 24, 2007, 08:02:33 PM »

If anything you should fit it above the unit. By putting it below it will cool down the element and get less smoke.

John
Logged

Martin [Admin]

  • Administrator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 19,089
  • Location: Peterborough, UK
    • Model Boat Mayhem
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #2 on: September 24, 2007, 10:04:37 PM »


I would recommend fitting some form or speed control.
The JJC unit has a fan in it.
( Have you seen the smoke unit on Arrow5 Springer tug?  :o - http://www.modelboatmayhem.co.uk/forum/index.php?topic=3471.msg61614#msg61614 )
Logged
"This is my firm opinion, but what do I know?!"    -   Mayhem FaceBook Group!

Voyager

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 820
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #3 on: September 25, 2007, 01:19:05 AM »

Thank you both for the advice O0 I will fit my fan above the smoke unit then, didn't stop to think that it might cool it down by fitting it under the unit :embarrassed:

Clear thinking was never my strong point....and don't even get me started on working out electronics ;)
Logged

funtimefrankie

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,260
  • Location: Birkdale, Lancashire. twixt the Mersey & the Ribble
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #4 on: September 25, 2007, 08:19:47 AM »

Sureluy, whether the fan is above or below it's still pushing/pulling colder air passed the unit?
Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,568
  • Location: Blackpool, Lancs, UK
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #6 on: September 25, 2007, 12:46:17 PM »

If the fan is below, cooling air will be passed over the part that you are trying to warm up.  With the fan above, the forced airflow does not need to go past the bottom of the unit, but could be ducted fron elsewhere.  The downside is that the fan is in the flow of vapour, which might or might not be good, but probably not (fan gunged up, centrifugal spray).  If the fan was mounted in a duct that fed into and assisted the flow up the funnel, this might well help.  There might not be more smoke, but the vapour should exit the funnel a lot faster and reduce the amount that falls back, greasing the deck.
Logged
"With the right tool, you can break anything" - Garfield

Voyager

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 820
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #7 on: September 25, 2007, 03:21:40 PM »

Cheers Malcom, you raised some good points O0 With the 12v smoke unit being so small i would still have room to fit some sort of air duct. I'm going to test it out on some loo roll, It's roughly the same dimmensions as the funnel, so should be a good proving ground for me to work from O0
Logged

FullLeatherJacket

  • Guest
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #8 on: September 25, 2007, 03:48:00 PM »

Voyager

I had imagined fitting the fan somewhere else (e.g. behind a scale duct), to draw air into the hull and raise the air pressure inside it - rather along the lines of one of those medical bubble-tents or a positive-pressure "clean room". If the funnel were the only exit then the consequent updraft should drag the smoke with it. That would avoid gunking up the fan blades or whirling the smoke into oblivion before it had a chance to get out of the big tube.

Never tried it so I can't put my usual "WFM" thing..........but suit yourself anyway! I'd be interested to hear the results of whatever you eventually try.

FLJ
Logged

funtimefrankie

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,260
  • Location: Birkdale, Lancashire. twixt the Mersey & the Ribble
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #9 on: September 25, 2007, 06:53:40 PM »

Perhaps, if you are ducting the air to the fan it could pick up by a motor and thus be warm air.
Also aiding cooling the motor(s)
Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,568
  • Location: Blackpool, Lancs, UK
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #10 on: September 26, 2007, 12:47:11 PM »

When I put a home made one in my Snowberry, there was very little smoke to begin with.  This was traced to sailing in winter (it will ground on ice, but is unwilling to back off it again) and a low ambient temperature causing lots of condensation in the funnel.  A tubular flue cured this.  A fan giving airflow up this tube would probably have helped.  I gave up on it when it became apparent that
1 the run time was drastically reduced :(
2 the deck above was showing sins of melting :'(
I'm uncertain as to whether converting the entire boat into a plenum chamber is really practical, it would probably be better to have the fan just blowing up the end of the duct.  Air will find a way in somewhere.
Logged
"With the right tool, you can break anything" - Garfield

Voyager

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 820
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #11 on: September 26, 2007, 02:46:15 PM »

I'll be getting a 12v battery at the weekend, so i shall get experimenting at the end of next week!  I've just this second had yet another brain wave...I hate it when that happens as it always hurts my brain afterwards :D Anyway, what do you reckon if i wired up the fan to the motor, this way the fan blows out the smoke at a faster rate at varying speeds of speed O0

...Right i'm off to take some Nurofen ;)
Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,568
  • Location: Blackpool, Lancs, UK
Re: Does anyone recommend using a fan with a 12v Graupner smoke unit?
« Reply #12 on: September 26, 2007, 07:00:30 PM »

Feed the fan through a bridge rectifier so it doesn't suck in reverse.  Sort of spoils the image when the smoke comes from everywhere exept the funnel.
Logged
"With the right tool, you can break anything" - Garfield
Pages: [1]   Go Up