The Game Changer

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digginfool
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The Game Changer

Post by digginfool » Mon Jun 24, 2019 9:41 am

It may not be my place to talk about this boat as it is not mine but I did get to take it for a ride yesterday and OMG. I've never seen a boat with a more appropriate name. This boat truly is a game changer. It's an 11 foot Benny Webb with a direct drive Waterthunder LS3. The owner of the boat said Waterthunder told him it made 1100 lbs of thrust on the stand. I believe it. I've never been on a boat that pushed you back in the seat as hard as this does. Period. The best part is that the engine sips fuel and you can buy that fuel on any corner. No rides to the airport, not paying $5.00/gallon. The setup costs no more than a well built 540. Can't wait to see how this pans out over the long haul. I'm seriously tempted to dump my 540 for this setup. If you see the boat, make sure you talk to the owner. Heck, he might even let you take it for a spin! If he offers you a ride, don't turn him down because this boat truly lives up to its name.
“When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it” - Bastiat

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skinnypockets
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Re: The Game Changer

Post by skinnypockets » Mon Jun 24, 2019 10:32 am

Hi diggin, It's always good to see new innovation. I remember a while back where Waterthunder was working on a thrust bearing for a direct drive. With 1100 lbs. of thrust it sounds like he figured it out. Does that engine have thrust bearing on it?
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digginfool
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Re: The Game Changer

Post by digginfool » Mon Jun 24, 2019 10:46 am

He has a machined bracket that fits behind the flywheel that I believe has a thrust bearing and acts as a motormount as well.
“When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it” - Bastiat

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OneBFC
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Re: The Game Changer

Post by OneBFC » Mon Jun 24, 2019 11:24 am

So funny, this is exactly what a proper ecotec boat feels like and peoples reaction to is when they drive one. The ecotec makes a few hundred pounds more thrust though.

Good to hear the LS DD is working well. I like the platform and hope to see more of it around.

Always things that can be improved, our "sport" needs the constant progress or it will fade eventually.
digginfool wrote:It may not be my place to talk about this boat as it is not mine but I did get to take it for a ride yesterday and OMG. I've never seen a boat with a more appropriate name. This boat truly is a game changer. It's an 11 foot Benny Webb with a direct drive Waterthunder LS3. The owner of the boat said Waterthunder told him it made 1100 lbs of thrust on the stand. I believe it. I've never been on a boat that pushed you back in the seat as hard as this does. Period. The best part is that the engine sips fuel and you can buy that fuel on any corner. No rides to the airport, not paying $5.00/gallon. The setup costs no more than a well built 540. Can't wait to see how this pans out over the long haul. I'm seriously tempted to dump my 540 for this setup. If you see the boat, make sure you talk to the owner. Heck, he might even let you take it for a spin! If he offers you a ride, don't turn him down because this boat truly lives up to its name.
-Russ
-----------------------------------
The only thing stopping you is FEAR
400+hp Ecotec, 12x7.6 DBDO, 80" 3B Maximus, 2.3 OX,85+mph, water = purely optional
Life begins at 2 BAR, Just a good ole boy

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Re: The Game Changer

Post by Seven3 » Mon Jun 24, 2019 12:21 pm

OneBFC wrote:Always things that can be improved, our "sport" needs the constant progress or it will fade eventually
I agree, but I disagree. No doubt, this platform will have its place. Just like CM gearbox boats, ecotechs, or even rotax powered boats have their place. Improvements in anything are always welcome, but sometimes tried and true is still best OVERALL. I think it’s hard to beat a fresh built AC motor with modern electronic ignition and a properly set-up fuel injection system. But I run light aircraft riveted boats. If I ran a big welded barge, I’m sure I would want a CM gearbox. I’d like to see more of these DD LS boats on the water, but us 540 guys aren’t going to be trading in anytime soon.

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Re: The Game Changer

Post by kwanjangnihm » Mon Jun 24, 2019 12:53 pm

diggin what model & size prop was he running?
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Re: The Game Changer

Post by digginfool » Mon Jun 24, 2019 5:13 pm

kwanjangnihm wrote:diggin what model & size prop was he running?
He's running a cut down (66") three blade Sabre.
“When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it” - Bastiat

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Re: The Game Changer

Post by digginfool » Mon Jun 24, 2019 5:45 pm

digginfool wrote:
kwanjangnihm wrote:diggin what model & size prop was he running?
He's running a cut down (66") three blade Sabre.

My bad. It's a cut down Alpha. Not Sabre.
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Re: The Game Changer

Post by Striker543 » Tue Jun 25, 2019 9:54 am

digginfool wrote:
digginfool wrote:
kwanjangnihm wrote:diggin what model & size prop was he running?
He's running a cut down (66") three blade Sabre.

My bad. It's a cut down Alpha. Not Sabre.
At such a short length I’m guessing he’s turning that thing well over 3,000rpms

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digginfool
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Re: The Game Changer

Post by digginfool » Tue Jun 25, 2019 10:24 am

I'm not sure what RPM he has it pitched to. I just know that by the time you hit 2,500, you don't want to be looking down anymore. :D
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Re: The Game Changer

Post by Seven3 » Tue Jun 25, 2019 2:27 pm

So is that one of the key elements to making a DD work, making the blades shorter so that you can spin it past 3K RPM? I always thought 3K RPM was the limit.

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Re: The Game Changer

Post by OneBFC » Tue Jun 25, 2019 2:50 pm

Seven3 wrote:So is that one of the key elements to making a DD work, making the blades shorter so that you can spin it past 3K RPM? I always thought 3K RPM was the limit.

http://www.epi-eng.com/propeller_techno ... peller.htm

It's fairly simple yet complicated at the same time. Like all things airboat really.

Disc loading is the task master that ultimately impacts efficient use of available power. The larger the disc the more thrust is produced from the same amount of power.

So, a short blade at higher RPM isn't as efficient as a long blade at low rpm.

That doesn't mean a shorter blade won't work. It just means you give up some potential thrust. However, if you gain 100 hp at 3500 rpm vs 3000 rpm, and you need a shorter prop to keep 3500 rpm tip speed in check, It may work out in your favor some.

1100lbs of thrust from 3 skinny, short blades is quite a bit. I would like to see the boat strapped to a test rig.
-Russ
-----------------------------------
The only thing stopping you is FEAR
400+hp Ecotec, 12x7.6 DBDO, 80" 3B Maximus, 2.3 OX,85+mph, water = purely optional
Life begins at 2 BAR, Just a good ole boy

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Re: The Game Changer

Post by Davie GSO480 » Tue Jun 25, 2019 5:25 pm

Hi all.....been a while sense ive been on this board.

I also had Dave build me a DD LS.
The motor is a LS3 block
EFI holley system
430 CI, Chevrolet cnc heads.

Dave (Waterthunder) has a thrust tester, it will measure thrust output.....it makes 1100 pounds + At 3600 with the Alpha 66
Most straight valve 0-540 make 940 =/-, angle valve 1000 +if its 10-to 1
I was at the last Thruman outting......Black full deck,,,,,,,,Midnight Rider..

The prop is a 3 blade Sensenich Alpha,,,,,,it makes thrust up to 3600......at 66 inches
Right now Im running it at 68 Inches and turning it 3200.
It will run with most 0-540 boats......
Ill post up a couple pictures and race videos...
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OneBFC
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Re: The Game Changer

Post by OneBFC » Tue Jun 25, 2019 5:41 pm

If those numbers are of a test run on a fully rigged boat vs engine on a stand with a prop on it, then that's good numbers for sure.

Would be nice to have someone post a video of that test since a 66 inch blade prop is darn short to produce that with.

Can tell you are all smiles about how it performs and really that's what it's all about.

Good stuff
-Russ
-----------------------------------
The only thing stopping you is FEAR
400+hp Ecotec, 12x7.6 DBDO, 80" 3B Maximus, 2.3 OX,85+mph, water = purely optional
Life begins at 2 BAR, Just a good ole boy

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Re: The Game Changer

Post by Davie GSO480 » Tue Jun 25, 2019 6:00 pm

It is what it is...it aint a full racer, but it is a fun boat to ride, performs amazing well, snaps hard.
Remember its about 20% displacement disadvantage to a 0 540
Those thrust numbers were on tester, not a boat.....No cage etc in the way.
The 3 blade Alpha is the only prop we tested that work in the higher rpm band, the Saber stopped converting about 3100,,,,,

https://southernairboat.com/gallery/#
I posted a couple pictures on main gallery

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Re: The Game Changer

Post by Seven3 » Tue Jun 25, 2019 7:07 pm

I saw you out there in January, nice boat.

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Re: The Game Changer

Post by CarMotorBarge » Tue Jun 25, 2019 10:06 pm

Davie GSO480 wrote:It is what it is...it aint a full racer, but it is a fun boat to ride, performs amazing well, snaps hard.
Remember its about 20% displacement disadvantage to a 0 540
Those thrust numbers were on tester, not a boat.....No cage etc in the way.
The 3 blade Alpha is the only prop we tested that work in the higher rpm band, the Saber stopped converting about 3100,,,,,

https://southernairboat.com/gallery/#
I posted a couple pictures on main gallery
You need to change your user name. So tell us a little bit about the headers. Who made them and what is different about them?

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Re: The Game Changer

Post by Sniper » Wed Jun 26, 2019 6:40 am

I think whats nice about this set up is you have an affordable set up and its a new motor not a 50 year old non Airworthy rebuilt motor
also you can go to any auto parts house and get parts for it even on the week ends at a reasonable price, Aircraft parts you can't just go buy anywhere and there is nothing cheap about them I know I have worked in the Aircraft industry for 42 yrs and like what was pointed out you can run it on pump gas, Dave has been a game changer and innovator for as long as I have known him, lycoming and Continental have done very little to improve there engine design in 50 plus years other than up grade there ignition system and add up graded fuel injection and to buy a new Airworthy engine from them cost more than a new high class airboat, are the motors reliable yes but they are also expensive to own and operate thats why I think what WaterThunder is doing is fantastic and affordable
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Re: The Game Changer

Post by Hambone79 » Wed Jun 26, 2019 10:34 am

Please help me understand my ignorant thinking what's so game changing about a V8 car motor DD spinning a prop built for a 4cyl AC Motor? Not bashing just trying to understand . beautiful boat BTW.

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Re: The Game Changer

Post by Seven3 » Wed Jun 26, 2019 10:38 am

I agree Sniper, this is a good thing. More options are always better, especially when you’re talking about cheaper options in a very expensive hobby. One thing that is causing me doubt is that prop. That’s not a lot of prop. I have a buddy who runs a 5 blade Alpha on his 540, I believe it’s a 70”, but not sure. Dave himself is always saying, the proof is in the prop. My angle valve IO-540 with Airflow Performance fuel injection and Pacemaker Ignition spins a 2 blade 72” Q pitched at the 3 mark at 2900 RPM. I’m curious what that DD would spin my prop set at the 3 mark, and conversely I’m curious what my 540 would spin that 3 blade Alpha at. I realize we can’t just swap props and see, because I can’t spin my engine that many RPM. But I think that would tell us a lot. But I’m not an engine builder, just merely curious because one day I’m going to need to power a brand new hull I have sitting in my garage...and if this DD LS stuff is a worthy competitor to my 540, I’d like to find out.

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Re: The Game Changer

Post by SWAMPHUNTER45 » Wed Jun 26, 2019 12:05 pm

Hambone79 wrote:Please help me understand my ignorant thinking what's so game changing about a V8 car motor DD spinning a prop built for a 4cyl AC Motor? Not bashing just trying to understand . beautiful boat BTW.
The LS even when configured to a 427 inch stroker is lacking in torque. It appears to get up into an RPM range where the build is targeting, it takes running a prop suitable for exceeding 2900 rpm and maybe actually up near 3400 ???

I know we looked at the LS specs and Mr Branch and I have been down to an other builders shop recently looking at his work with the platform. I personally think if the stroke can not be lengthened significantly it's yield will not be much more than the old 400sbc sans some reduced weight.

The featured boat is a beautiful build and ideal for that application. Wishing you years of use and safe sliding!

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Re: The Game Changer

Post by digginfool » Wed Jun 26, 2019 12:08 pm

Davie GSO480 wrote:Hi all.....been a while sense ive been on this board.

I also had Dave build me a DD LS.
The motor is a LS3 block
EFI holley system
430 CI, Chevrolet cnc heads.

Dave (Waterthunder) has a thrust tester, it will measure thrust output.....it makes 1100 pounds + At 3600 with the Alpha 66
Most straight valve 0-540 make 940 =/-, angle valve 1000 +if its 10-to 1
I was at the last Thruman outting......Black full deck,,,,,,,,Midnight Rider..

The prop is a 3 blade Sensenich Alpha,,,,,,it makes thrust up to 3600......at 66 inches
Right now Im running it at 68 Inches and turning it 3200.
It will run with most 0-540 boats......
Ill post up a couple pictures and race videos...
I'm glad you weighed in since, as I said, it's not my boat. I didn't know it was set up to spin all the way to 3,600 RPM. I'm not sure how far I pushed the engine because I certainly wasn't out to thrash the guy's ride but I doubt I took it much beyond 3,000. I was just texting Seven3 and the thought came to mind that besides getting the engine into at least part of the powerband requiring the shorter blades (3,600 RPM), how much did it have to do with the cam? That's a pretty radical cam so my thoughts were the smaller blades were needed to get the snappiness down low before the cam hit the pipe since a cam with that much overlap is going to be a bit weaker in lower RPMs. Thoughts?
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Re: The Game Changer

Post by CarMotorBarge » Wed Jun 26, 2019 12:28 pm

Does anybody know the specs on the cam? :stirpot: :stirpot: I think everybody knows the answer to that.

So why do you think it was a radical cam? What RPM did it idle at?
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Re: The Game Changer

Post by digginfool » Wed Jun 26, 2019 12:39 pm

CarMotorBarge wrote:Does anybody know the specs on the cam? :stirpot: :stirpot: I think everybody knows the answer to that.

So why do you think it was a radical cam? What RPM did it idle at?
Very lopey idle is the only indication. I have no idea what the specs are. Did not pay much attention to the idle speed but I did note it was a little on the high side. You definitely come into the dock pretty hot.
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Re: The Game Changer

Post by Davie GSO480 » Wed Jun 26, 2019 5:00 pm

The cam is one part of getting the direct drive to respond and run like it does.
Why would Water thunder give away his cam spec's?

My engine idle at 650 rpm's.
The cam lope goes away at 900 rpm...
Propellers tip speed is your limit here, the longer the prop, the faster the tip speed at the same engine rpm.
I have 2 different hubs from Sensenich, same Alpha blades. One is 66'', the other 68''
The 66'' at 3600 is at Mach .92, or 707 mph at tip, At 68'' at would be Mach .95 or 728 mph.
I turn the 68'' 3200 rpm's
Above (depending on tempture) much .92 your just making noise

With the 66''its a little quicker
with 68'' it has alot more low push, partly because its in cleaner air beyond the engine
I have a video racing a Hawk step with a 9 to 1, straight value 0-540,,,,let me see if i can figure out how to load it here.
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