2:1 vs 2.68:1 - Beating the Horse Just a Little More

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airduds
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2:1 vs 2.68:1 - Beating the Horse Just a Little More

Post by airduds »

I'm currently having what will be my fourth airboat built. First was a 18x8 ex-tour boat with 500 Caddy DD/six blade warp drive - a good starter but couldn't even look at dry ground without getting stuck. Second was 18x8 Alumitech with 454/425, 2:1 belt, and stacked Ivos - until I messed the props up this boat actually ran great - climbed dikes and crossed roads four up with no problem at all. Third boat was 16 foot Rivermaster with 470 GPU which really did about anything I needed to do but sometimes needed a running start.

Boat being built is 14'8" aluminum deckover with 2' rake. Seating is two up and three down. Power is going to be 383/425 stroker. I was originally going to go with 2:1 Stinger and Whirlwind three-blade Stump Puller but after reading so much about the 2.68 you guys have really got me thinking.

So now for the questions:

Does Stinger offer a 2.68?

If I go with the 2.68 and stay with the Stump Puller will I be able to put enough pitch in the three blades to perform well or should I look at something else from the get-go? Kind of prefer to stay Whirlwind or Powershift, but will do Sensenich if it's the right thing to do.

I don't care about top end at all. If the boat will run dry like I want the top end will be good enough. I want the most static thrust I can get out of the 383.

Great website. Thanks in advance for the answers.
Last edited by airduds on Wed Feb 21, 2007 12:23 pm, edited 1 time in total.

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Duece
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Post by Duece »

I'm not an expert on the props, but whatever you do I would go with the 2.68:1 box. I've got one I put on a zz4 350/355 hp and man has it made my boat rock! I'm turning a Sensnich 2 blade ultrawide 78" on pitch setting 2 at 5200 rpm's on the motor. I had a 2:1 with a 78" K series and the difference in night and day. There are some pics in my gallery that show a hill I could barely climb with momentum before the 2.68 and now I climb it with ease.

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dantheairboatman
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Post by dantheairboatman »

Yes stinger has 268.4. I do not no about whirl wind but Sen. 3blade wide q or super wide will be perfect! I like the Sen. better than the powersshift/water walker.You will not be sorry. I run a 288 on a three blade Sen. and love it also run 268 . You will not over turn your motor if you pick the right prop and put the pitch to it and let the gear work for you! I can get you a Singer . cntry 141 can give excellent advice.
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Post by Ruagatr »

Everyone knows I like the 2.68---and even more so with a small block. But the propeller is like asking ford or chevy questions. I have heard and driven boats with both propellers with gear reduction. The Sensenich is 50% quieter to my ears than the Whirlwind. Now that's only a few decibels, but it makes a big difference. The shape of the sensenich also looks like an engineer designed it, rather than just making a slab sided carbon fiber propeller like some resemble. Good luck with your choices----but run the 2.68. Charles

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airduds
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Post by airduds »

Thanks for the advice. I'm going to the 2.68 softdrive and 80" Master Blaster 2.3 three-blade.

Like I said earlier I'm after static thrust. If it's quieter too that will be an added bonus.

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Post by crowhater »

Ruagatr wrote:Everyone knows I like the 2.68---and even more so with a small block. But the propeller is like asking ford or chevy questions. I have heard and driven boats with both propellers with gear reduction. The Sensenich is 50% quieter to my ears than the Whirlwind. Now that's only a few decibels, but it makes a big difference. The shape of the sensenich also looks like an engineer designed it, rather than just making a slab sided carbon fiber propeller like some resemble. Good luck with your choices----but run the 2.68. Charles


Charles,
I talked to faren this morning about buying 3B super wide and the price is 3grand. He is trying to sell me the wirlwind prop because he feels it is a better deal and makes the same thrust. I am selling my 3B falcon with hub for 2k and I am also selling my 1.7 rotator for 1500.00 both of these items have less then 30 hours.
18x8 Alum, 496 BBC, 2.6 CH4, 4B 82" S-blades

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Post by Red Dwarf »

Fatboy just switched from a Master Blaster to a Superwide Sensenich and said the performance is a lot better. They are quieter too, and quiet is a good thing

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Post by Root Pass »

Good to see you back Red hope the eyes are doing ok.
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Post by fatboy0054 »

WITH A POTTER CADILLAC ! I WOULD GO WITH THE SUPERWIDE ! 268 ! NOTHING WRONG WITH 2.3 ! JUST WONT HOLD THAT MOTOR AND BOX ! :D
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Post by T-REX »

fatboy- what do you mean by "wont hold that motor and box??"

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Post by fatboy0054 »

WONT HOLD MY RPMS DOWN WHERE I WANTED THEM !I WANTED 4500 MAX ! SOME DAYS IT WOULD DO 5000 ! JUST NOT ENOUGHT PROP FOR MY LIKING ! I CAN TURN 5000 ALL DAY. BUT DONT HAVE TOO ! I NEVER SEE OVER 4000 NO MORE ! DRY UP HILL DEEP WATER THREW THE BUSHES! ITS PRETTY NEAT I KNOW ITS THERE IF I NEED IT ! IT JUST RUNS EASY AND LESS SOUND ! POEPLE SAY I DIDNT HEAR YOU COME UP ! THAT S THE DEAL !I JUST WEEDED OUT BS AND LISTEN TO RITE ONES ! THEY DID GOOD, SO DID I ! :D JUST WOULDNT HOLD WITH A 237 BOX !LESS WITH A 268 BOX !
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Post by T-REX »

thanx fat boy- i was almost temped to use ruagatrs' old prop with the 268 but i guess thatll be on the auction block soon enough, gonna get the new sensenich for sure.

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Post by Sniper »

I have a 2.68 with the sensenich wide blade and I love it you can't go wrong with that combo
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Post by T-REX »

roger that- seems whatever engine combo you have everyone is real happy with this combo.

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Post by fatboy0054 »

EVERBODY WILL TELL YOU THE NUMBERS ARE ALMOST THE SAME ! BUT BY YOUR (BUTT DYNO) I DROP 600 RPMS ALL AROUND ! NO MORE THAN 4 SECOND FULL THOTTLE BLAST TRYING TO FIND A PLACE TO LAND ! I WISH SOME ONE WOULD POST A PICTURE OF THE A WATER BRAKE DEAL ! FOR A BIGGER BOAT DEAL ! JUST FOR STABILITY!
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Post by Waterthunder »

We put a computer on board a step hull and made about 20 400ft passes with it. We documented MPH and E.T. every ten feet! What's funny which I have absolutely gave up trying to get across is peak thrust test numbers. First off every thrust test number out there is on a stationery boat, I'm sorry but I don't care to much how much thrust my boat makes sitting still I'm more concerned about when it's moving! Anyway to prevent the onslaught I will just state that the prop that showed the most thrust on the thrust test performed far worse then any other prop at MPH and ET. Each prop did have an area in the pass that it excelled accept for the prop that made the most thrust in a stationary thrust test. To put it plainly it stunk everywhere! Most the other props were close with only one standing out of the crowd!
THE PROOF IS IN THE PROP!

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Post by Ruagatr »

This kind of post is so unhelpful without the real data......and the truth being posted. Just put the facts up and let the chips fall where they may. Respectfully, Charles

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Post by Red Dwarf »

If you go back and search, he has posted the MFG's before, but I think that was also before Sensenich came out with the Superwide.

For me, the biggest thing is that you can get so much performance out of the Sensenich Superwide at LOW RPM which is the whole jist of what we are trying to do here. Ultimately it leads to lower engine RPM and also less SOUND, and to me that is the most important thing, that we can make our boats run better AND quieter. That may help us keep runnin these things without being hated by the rest of the world.

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Post by Duece »

Red,
Dead on bro, the Q series Sensnich are quieter. Once I put mine on my boat the sound difference was amazing! In skinny water, cruising, my boat (not meas, but to the naked ear) is 1/2 as load as it used to be. My fuel consumption is so much better than it used to be. The only place I didn't see a large difference was in deep water, but all around the 2:68 was a great switch for me. I wasn't doing it to quiet down my setup, but it that just ended up being one of the perks of switching boxes and props.
The Q series are quieter, my dad just put one on his 540, and it is much quieter. He had a wood paddle prop that could shake a house of it's foundation, and now on plane, cruising his is noticably quieter.

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Post by Waterthunder »

Right now I feel the Super wide Q series is the best prop out there for push and a low sound signature and it saves fuel because it has so much more push at a lower RPM! However there may be another prop in town which I will be testing shortly. As for posting the results of the prop testing it took me ten years of arqueing the 2.68 and still gotta arque it on a daily basis. I sure don't feel like going thru that again on props. The airboat prop testing were about to start will be more exstensive then anything else that has been done and thrust will be measured in a REAL WORLD inviroment as it's moving thru the air!
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Post by Olf Art »

Thunder, thinkin out loud again ....

You know those little computers that they sell that sit on the dash board of a car and measure rate of acceleration and all sorts of other things like estimated E.T ?
Why wouldn't one of those be useful in a prop comparison test ?
You could use it right on the water.

olf
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Post by hmgm123 »

Water Walker is suppose to be coming out with a new prop that going to kick everyone else butt in performance. I couldn't remember if that was to suppose to be kept quiet or not but the cat is out of the bag now. :D

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Post by Red Dwarf »

But how about sound

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Post by Waterthunder »

I tried one of those a few years ago but the accelerometer inside of them get's screwed up from the motion YAW AND PITCH of being on the water. I tried and tried but it didn't work, I realized this when I got mine to read a 142MPH in 400feet! As much as I would have loved to claim it I knew it was false information. I even started on the bank and slid into the water but they just don't work on the water. just as the manufacture told me but I guess I had to try it anyway and find out for myself they they didn't work !
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John C
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Post by John C »

hmgm123, I heard that Water Walker is using different material in there new props, and they are supposed to be almost 50% lighter and alot stronger than the old ones. But I haven't heard anything about a different blade design.

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