Hydrodynamic Ecstasy

Please discuss here all your remarks and pose your questions about all racing series, except Formula One. Both technical and other questions about GP2, Touring cars, IRL, LMS, ...
johnny comelately
johnny comelately
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Hydrodynamic Ecstasy

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Put the headphones on and boost the pleasure centre :wink:

johnny comelately
johnny comelately
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Re: Hydrodynamic Ecstasy

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Not the best of photos for this question, for all the aerodynamicists if you can turn your minds to another fluid, any ideas for improvement of prop performance?
Image
Image

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Stu
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Re: Hydrodynamic Ecstasy

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Looking at a few of those clips they look pretty effective; one of them launched out of the water!!
Perspective - Understanding that sometimes the truths we cling to depend greatly on our own point of view.

johnny comelately
johnny comelately
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Re: Hydrodynamic Ecstasy

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Two separate race formats.
The second two photos are from Australian Offshore Superboats,
Some of the hulls are ex from Saudi teams and are a few years old.
Being the first involvement with this type, cats with twin 510 cid lazy engines, it struck me that the area where the prop wants to pick up water to process, it is being fed very turbulent water.
The photos are not good for showing this but it seemed if they streamlined the incoming area to try and minimise turbulence (cavitation effect) they would pick up some drive.
This is mainly in the stepped shape where the prop shaft is located but also change the design for propshaft control to get rid of turbulence causing parts.
Interesting observation about this class is their obsession about minimum weight, but not much else, to the point they soak the lifting straps which apparently are included in the minimum weight.
Will they eventually use hydroplanes a la AC75's ?
What if they added the jet format to the props?

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Airshifter
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Re: Hydrodynamic Ecstasy

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Trust me on this, there isn't much left in the bag when it comes to racing propeller designs. If you can imagine it, they have tried it.

As for the surface drives, though not adopted by all the big guns they gain huge advantage in calmer waters, and these days they try to keep the boats more in the water than flying. Like anything else with big power, they go faster when attached to the drive medium.

Back before the days of the lighter weight boats, some of the Superboat class boats had 3 and 4 blown and injected big blocks. They were pushing upwards of 5000 horsepower. You'll notice how stout the props are near the hub at the heavier end of the blade, and there is a reason for it. There were offshore races for a few years here where I live, but it didn't last long. Usually fairly violent on the guys in the boats, as they picked an often very rough time of the year to do it.


As for watching, the drag boats are actually more fun to watch IMHO. Either offshore or lake bound boats are usually far enough off the shore and big enough that it's hard to really get a good first hand view of the speeds and take it into proper perspective. The drag boats.... well it's hard not to see how well they hook and go and you are generally close enough it's more like watching drag cars, with the exhaust impulses rattling your chest as they fly past.

johnny comelately
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Re: Hydrodynamic Ecstasy

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Airshifter wrote:
Wed May 04, 2022 3:32 am
Trust me on this, there isn't much left in the bag when it comes to racing propeller designs. If you can imagine it, they have tried it.

As for the surface drives, though not adopted by all the big guns they gain huge advantage in calmer waters, and these days they try to keep the boats more in the water than flying. Like anything else with big power, they go faster when attached to the drive medium.

Back before the days of the lighter weight boats, some of the Superboat class boats had 3 and 4 blown and injected big blocks. They were pushing upwards of 5000 horsepower. You'll notice how stout the props are near the hub at the heavier end of the blade, and there is a reason for it. There were offshore races for a few years here where I live, but it didn't last long. Usually fairly violent on the guys in the boats, as they picked an often very rough time of the year to do it.


As for watching, the drag boats are actually more fun to watch IMHO. Either offshore or lake bound boats are usually far enough off the shore and big enough that it's hard to really get a good first hand view of the speeds and take it into proper perspective. The drag boats.... well it's hard not to see how well they hook and go and you are generally close enough it's more like watching drag cars, with the exhaust impulses rattling your chest as they fly past.
Enjoy your observations.
It was more the hull design where it feeds water onto the prop. In the (2020) superboats in Australia it is very turbulent.
They are on at Hervey Bay, Queensland, this weekend only a couple of hundred yards from the beach. Fly Qantas :wink:
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Airshifter
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Re: Hydrodynamic Ecstasy

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I hope you get to really enjoy the races. It's something that a lot of people never get to experience.

The timing of this post took me back to when I followed the sport more closely, and my huge desire to get down to Miami to see some of the legendary US builders and locations. I'm not sure just how far they were known but the legendary "Thunderboat Row" started by Don Arownow was the playground of the ultra wealthy into the offshore game.

Along with Fort Apache Marina, it's the place of boat building and rigging legends. Sadly I never got down there back in the day, and most of it is gone now as the industry has moved all over.


It would have been a great change to the Miami track vs the current false marina. Though I'm not sure all the F1 fans would have recognized it, if they built a false Fort Apache Marina and Thunderboat Row equipped with the still fairly common offshore mega boats, it would have been an epic way to tie in some of the history of Miami.

johnny comelately
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Re: Hydrodynamic Ecstasy

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Lake Havasu top fuel October 11 262.238 mph 1000ft


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Airshifter
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Between Lake Havasu and the Parker strip, they had any kind of fast boat you can imagine. We used to head out there and party a lot on the weekends when I was out in military schools. I think the drag boats were "only" running 225 or so MPH at the time, but it was still wild to watch.

Down on the river side, the fly bys at some of the floating bars were almost as much fun. We saw more than a few boats get swamped showboating, and it always stirred up the crowds. Crazy times.

J.A.W.
J.A.W.
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Re: Hydrodynamic Ecstasy

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Here's an example of fairly close in to city-shore dramatics,
from back in the day - before big boomer 2-stroke turbo Detroit-Diesels
roosting water & blasting smoke - were banned for being too anti-social...

"Well, we knocked the bastard off!"

Ed Hilary on being 1st to top Mt Everest,
(& 1st to do a surface traverse across Antarctica,
in good Kiwi style - riding a Massey Ferguson farm
tractor - with a few extemporised mod's to hack the task).

johnny comelately
johnny comelately
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Joined: Thu Apr 09, 2015 11:55 pm
Location: Australia

Re: Hydrodynamic Ecstasy

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1,000 foot staggered start grudge race for a case of beer! Voodoo ran the course in 3.53 seconds at 269.396 MPH


johnny comelately
johnny comelately
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Joined: Thu Apr 09, 2015 11:55 pm
Location: Australia

Re: Hydrodynamic Ecstasy

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Cannot help it your Honour, I am addicted


johnny comelately
johnny comelately
80
Joined: Thu Apr 09, 2015 11:55 pm
Location: Australia

Re: Hydrodynamic Ecstasy

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Last one, promise
a sprinkling of alcohol engines and a couple of oopss