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Airboat in the wind?
Posted:
Sat Aug 20, 2016 7:24 pmby Duplex Lover
I have Never been in an airboat.
SOOO
Questions abound.
I'm building a Mini airboat with a catrermeran type hull system and a VW bug motor. It is coming together ( ever so slowly ) But far from even hitting the water, Maybe next year.
I can see that other then pushing you sideways the current should not affect the
Forward motion much, as little water ,they draft.
With the "Prop" not pushing on water, current should not be an Issue, in my mind.
But what about wind?
I know wind makes a tuff drive when it's blowing across the boat.
With my top up on the big boat it can be trouble some.
How much wind can I expect to drive against ?
IF your boat can go lets say 20mph , In a 20 MPH wind am I stopped?
Anyone have some insight or experience ?
Re: Airboat in the wind?
Posted:
Sun Aug 21, 2016 9:09 amby aunt betty
In college the class I hated the most was called "dynamics" and you're asking dynamic questions that are difficult because you're taking it to the "fluid dynamic" level. I still have my fundamentals of fluid dynamics book but to get me to open it is gonna cost you three Beretta 390's.
Asked the experts in the facebook group "high performance tillers" and they said "what size prop you runnin?'" and if the motah has stock carbs.
Bottom line. Build it and if it floats and the motor runs get a GPS and see how fast it'll go. That's what errybuddy else does.
Re: Airboat in the wind?
Posted:
Sun Aug 21, 2016 9:26 amby Duplex Lover
That's what I'm doing.
All uncharted water to me.
Yup stock Carb, all one of them.
The Prop will be driven by a Snowmobile clutch /turuq converter.
That starts out at a 3 to 1 reduction and goes to a .70 to 1 at top RPM If the little Bug motor , 50 Hp., Will turn it that fast.
Prop sizes is unknown, I have not ordered it yet but it looks like a 60 or 62 inch two bladed wooden prop Is about what I need , the prop people will advise me what to get for the pitch, they said ,when I order it.
Re: Airboat in the wind?
Posted:
Sun Aug 21, 2016 2:56 pmby Rick
I've no notion how it will go with a small engine (less weight and lower CG?) and cat hull, but our standard airboats can't attain much speed at all without becoming dangerously light up front when running into a wind/chop unless their trim tabs are lowered.
Re: Airboat in the wind?
Posted:
Sun Aug 21, 2016 3:01 pmby SpinnerMan
To get enough force to move your boat 20 mph forward, the air will be pushed off the blades at much more than 20 mph. My guess is that it will be pretty similar to a traditional boat capable of moving 20 mph going into a 20 mph head wind, except you may have a bigger cross section so you will get a little more wind resistance than a boat with a traditional motor.
And Rick's comment is a completely different issue of safety, which I've never been in an airboat, so I have no idea. You might be able to go pretty fast, but you may not want to.
Re: Airboat in the wind?
Posted:
Sun Aug 21, 2016 5:50 pmby aunt betty
Just keep the wind at your back at all times and you won't have to worry about power loss due to head-winds.
