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 PostPosted: January 11th, 2014, 1:22 pm   
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I was just thinking that my battery is I the center of my boat right now... I could relocate it to help.

It "depends". If we use the movable weight and a few pounds solves the issue the best place for the battery is the middle from an overall handling perspective of a lake rocket.

If you want a static solution for only you in the boat yes moving the battery to the left or right may help.

Let's try the weights first and go from their, however I'm not very interested in 115 mph runs my friend. I've already seen too many accidents :) I enjoy my snowboard buddy!

My STV has the battery on the same side as the driver ! Why might that be... It does not, pass "common" sense but the math works in my boat.


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 PostPosted: January 11th, 2014, 1:32 pm   
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what i wonder, is there any deck or hull mods we can do to correct this high speed lean, without bothering the low speed handling characteristics.

I don't know a lot about it but I have been told a lot of experimentation was done in the 80s for this including "air brakes" which we're outlawed.

I guess the primary reason is handling and cost, to, make an airfoil useful it need to have variable impact on a boat. On a car a static force by an airfoil is significant BUT the car is not "balancing" on a point, on top of that it is not balancing on a moving point as speed changes.

The movement of the balancing point on boats is one of the most interesting aspect of performance boats that the car guys do not need to consider as much.

A couple pounds of force on a boat at speed can significantly change it's handling characteristics, left side, right side, bow all, would positions can have major differences at speed.

So setting up a airfoil might work at one speed but be a disaster at hight speeds. So yes I think you could make a slight airfoil to help balance the boat, but I'd bet you can do it with weight distribution also. Otherwise they'd be doing it in F1H2O for sure.

But this is all conjecture I know a little enough to be dangerous


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 PostPosted: January 11th, 2014, 3:53 pm   
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MOTOboat wrote:
what i wonder, is there any deck or hull mods we can do to correct this high speed lean, without bothering the low speed handling characteristics.

I don't know a lot about it but I have been told a lot of experimentation was done in the 80s for this including "air brakes" which we're outlawed.

I guess the primary reason is handling and cost, to, make an airfoil useful it need to have variable impact on a boat. On a car a static force by an airfoil is significant BUT the car is not "balancing" on a point, on top of that it is not balancing on a moving point as speed changes.

The movement of the balancing point on boats is one of the most interesting aspect of performance boats that the car guys do not need to consider as much.

A couple pounds of force on a boat at speed can significantly change it's handling characteristics, left side, right side, bow all, would positions can have major differences at speed.

So setting up a airfoil might work at one speed but be a disaster at hight speeds. So yes I think you could make a slight airfoil to help balance the boat, but I'd bet you can do it with weight distribution also. Otherwise they'd be doing it in F1H2O for sure.

But this is all conjecture I know a little enough to be dangerous


we need traction control computer systems, to control airfoils and trim tabs, trim angle,etc to keep er flat and straight ..

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 PostPosted: January 11th, 2014, 5:04 pm   
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Yes the CG is certainly is dynamic in the MVP...you forgot another variable...angle of attack...that why a hull like the STV will fly faster flat... flying the the boat flat with the lift factor in the tunnel put the CG at the seat of your pants...increase the angle of attack (trim) to more than +2 degrees and your CG is going to the transom again with an increase of fronatl area on the hull bottom now...and then your scrubbing speed ;)....Again on the V bottom... they have so much frontal area (on the hull) the air has to do something so it basically makes it lean as there is ceratinly a pressure differential on one side of the hull top the other... thus the lean....Now to remove the aero lean...if someone could come up with a way to pressure equalize the hull bottom (i think the Allison does have this design into the hull)...then whole new ball game....the STV is good at pressure equalization at speed as it it good at displacing the air over the deck and thru the hull.

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 PostPosted: January 11th, 2014, 8:10 pm   
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The angle of attack affects the efficiency of the aerofoil. If a modv or tunnel is designed well it has a good part of the deck shaped like the top of a wing. So if you cut the boat in half you'd see the bottom has a shorter length for air to pass over than the top. This causes a high pressure zone below the boat and a low pressure zone on top of the boat.

One reason a STV has so much more lift than my stoker did is the STV has more of an aerofoil shape than my stoker did, it had none.

So with tunnels and well designed modv boats you get an wing flying just above the water. A boat wing (tunnel) is specifically designed to not provide too much lift otherwise it becomes a plane.


Angle of attack is just like a plane, if you are too aggressive you get eddy currents on top of the aerofoil Spoiling the lift affect of the wing. So while area of the front maybe a factor, from my exposure it's actually the reduction of the efficiency of the aerofoil that's the larger contributor.

;)


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 PostPosted: January 11th, 2014, 9:34 pm   
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MOTOboat wrote:
The angle of attack affects the efficiency of the aerofoil. If a modv or tunnel is designed well it has a good part of the deck shaped like the top of a wing. So if you cut the boat in half you'd see the bottom has a shorter length for air to pass over than the top. This causes a high pressure zone below the boat and a low pressure zone on top of the boat.

One reason a STV has so much more lift than my stoker did is the STV has more of an aerofoil shape than my stoker did, it had none.

So with tunnels and well designed modv boats you get an wing flying just above the water. A boat wing (tunnel) is specifically designed to not provide too much lift otherwise it becomes a plane.


Angle of attack is just like a plane, if you are too aggressive you get eddy currents on top of the aerofoil Spoiling the lift affect of the wing. So while area of the front maybe a factor, from my exposure it's actually the reduction of the efficiency of the aerofoil that's the larger contributor.

;)


Dave, i know this is way off topic but speaking about your old stoker,.. can i cut my baker in half and make a drag boat like this :lol: it could have wings :mrgreen:

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 PostPosted: January 11th, 2014, 9:46 pm   
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Yes agree on the wing concept, but the lift is both hydro and aero and i would think an equalization has to occur or the boat is going over if it + under and - above...of course angle of attack can control this too ;)

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 PostPosted: January 12th, 2014, 12:06 am   
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Yup all forces need to add up....
Last word na na.. ;)


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 PostPosted: January 12th, 2014, 12:21 am   
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so now what happens when we throw a step in the pad :?: Image

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 PostPosted: January 12th, 2014, 12:56 am   
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It just changes where the hydrodynamic forces is applied to the boat and effectively extends the engine setback.

By the what have you done to that boat, it doesn't look like now doe it?


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