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Thread: I Need help !!

  1. #1
    Newbie Club Member
    Join Date
    May 2014
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    Lightbulb I Need help !!

    Hi I am a new member and i am interested in quiet slow craft for travelling about in.
    Many years ago I had an Osprey Falcon ( it had a 503 Rotax engine and a 900mm prop ). it was great fun but very loud !!!
    So I think what i may need is a craft with a large slow moving thrust fan and a smaller lift engine ?

    can anyone tell me where to start ??
    PS 1)Has anyone ever used a water cooled 200cc LE "Vollosette" engine??
    2)Have there been any electric powered craft made ??

    any help welcome.
    Mekon

  2. #2
    Forum God > 400 posts Club Member
    Join Date
    Mar 2009
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    978

    Default Re: I Need help !!

    Hi - greetings from the Magnolls race meeting near Blackburn Lancs so I'm afraid its a bit of a quick initial reply.
    The Velocette Viceroy engine was used in the 60's but I don't think is made anymore. A long as you use a low revving 4 stroke engine such as the 35bhp Briggs and Stratton engine used in many F35 craft with adequate air intake and exhaust silencers there is no problem with engine noise, the problem is fan noise. That will be the same problem with electric power which some are experimenting with. Electric power has its own probs at the moment especially cost.
    As you suggest the key to fan noise is to lower the tip speed from around 120m/sec commonly used to around 80 m/sec, reduce duct tip clearance to around 5mm with a strong, perfectly round duct, remove all the clutter in front and behind the fan which disturbs the air going through the fan and 'gas flow' any lift splitters etc behind the fan.
    Whereabouts in the country are you?
    Keith

  3. #3
    More than 30 posts! Club Member
    Join Date
    Aug 2014
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    37

    Default Re: I Need help !!

    Have you looked at the Sevtec range of hovercraft? (http://amphibiousmarine.com/) They use a propeller for thrust & low revving 4 stroke engines, so fan noise & engine noise is kept to a minimum. You wont break any speed records in them or win any beauty competitions, but saying that they can reach speeds around 40 mph if conditions are favourable.

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