Sport hydro stepped center section rule

[Grimracer]

Truth is.. the air will slow down as the opening gets wider.. compression is gone. In effect you are moving the break point forward.

Grim

 

[anthony_marquart]

So what is the overall opinion on this. If I'm not intending to pack air under the boat will this free up the hull from water drag. Or maybe I shingle the bottom like some sponsons are done. This will probably make the boat need a lifting prop like a rigger? The steps not the shingles.

 

[Hydro Junkie]

Anthony, rather than try and re-invent the wheel, why not look at the boats that are usually the fastest and best handling and try to figure out what makes they perform as well as they do and start from there? Every "hot" boat has things that make it work like it does, be it sponson design, bottom shape, balance points, etc.

 

[anthony_marquart]

It's just my nature. And I know we have not discovered everything there is to model boats

 

[Hydro Junkie]

Tech changes so boat hulls must follow, that is the order of things. That being said, we will always be learning more as time goes on

 

[Mike Larson]

Anthony... maybe work on a shorter overrall width at the transom.... ie visualize a rigger tub back...( more or less) ie: just enough for strut and rudder mount . less weight, thinner profile.... all aero'd in.... speakin easy... idk what the rules are?... 'luck... glue something.... Mike

 

[scottmeyers]

I applaud your efforts Anthony, and I wouldn't hesitate to try it for one moment! Maybe it works, maybe it doesn't. Everything else is just an opinion. FYI we put a very small step at the break in our 2.5 stock hydro a few years ago and broke the world record three times with it. Not saying that was the reason, just want to point out that if you always do what the fast guys do you'll never be faster than they are. Do what the fast guys do until you run with them, and then.... Try new stuff!!

 

[dschigoda]

If we do what we have always done, then we will get what we have always got.

Trying new designs may not work at first, but if the new designs lead to a better understanding of the aerodynamic and hydrodynamic principles, then this learning could be incorporated into still different designs, and could lead to better handling, even faster designs.

I've been puzzling for years (for model hydros, not full size) on whether the side air traps on 1/8 scale and sport hydro boats add lift or take away lift? And if so, is the lift acting behind the CG or ahead of the CG?

And how critical is the placement of the "break" in the bottom of the hull? What would happen if the break was placed ahead of the CG? What if the break was not a break at all, but a gradual curve?

Is there an interaction between the side air traps and the "break" in the bottom of the hull?

The nice thing about working with models is that you don't have to go broke trying out new ideas and designs, like some of the full size teams and owners have done over the years.

 

[anthony_marquart]

all good points Dave,.. I still really think that alot of the air trapping of older designs was needed to get the boat free from water with less HP,.. but with the power we have now,.. I think it's just drag,.. we'll see.. ill be trying something..

Ive also got to think that someone has already done this,...

 

[Grimracer]

yep............

 

[anthony_marquart]

Mike,.. now you have got to elaborate on that last comment,.. would really suck to spend a ton of time and $$ to build something that someone already knows will not work,..

and the air traps and break points most definitely are tied to each other in relation to how the hull lifts..

 

[lohring]

Not about sport hydro designs, but we played a lot with width, air traps, and wings on the center section of SAW riggers. The hull had no breaks and ran at a zero angle to the flat bottom.Lift is always good, but you need to keep the prop in the water. Too much aft lift resulted in the prop blowing out. In the end we ran a slightly lifting center section with airfoils on the sponson tubes to kill the lift when needed. We felt the side plates helped guide the flow over the top of the center section to slightly help the lift. Air traps gave too much lift.

Lohring Miller

 

[Grimracer]

Mike,.. now you have got to elaborate on that last comment,.. would really suck to spend a ton of time and $$ to build something that someone already knows will not work,..

and the air traps and break points most definitely are tied to each other in relation to how the hull lifts..

Not really.. the value is on you trying things.. sounds like you are going to do what you want anyway.. (I know I did)

And becides.. you MIGHT hit somthing else that takes it to the next level.

Grim

 

[Samuel Hagan JR]

Anthony if we can get Impba to allow Sport boats to have a recessed transome and rear skis like the real ones I wonder how much that would change the character of the boats.

 

[Grimracer]

Lets hope that day never comes......... the draw to sport 40 IS its character! lol

YEEE HAWWW

Grim

 

[anthony_marquart]

I'm a data guy for sure. But I will certainly listen. If I never did anything that lots of guys said wouldn't work I would not have done half the things I've done that worked.

 

[lohring]

I bet that for every ten good ideas we tried we were lucky to find one that improved things. Sponson tube streamlining was my favorite. Mike "wind tunnel" tested sponson tubes with an ingenious leaf blower setup and proved that a streamlined tube had lots less drag. However, streamlined tubes didn't improve the speed around 100 mph a measurable amount. The air trap testing mentioned above was also very interesting. We took boats to the shop, glued on parts, then tested and cut things off. Don't be afraid to try things. Finding what doesn't work is more valuable than finding what does.

Lohring Miller