Dialing in new boat..

Longest running airboat discussion on the internet.
User avatar
Prototype
Southern Airboat Member
Posts: 687
Joined: Sat Jan 26, 2013 2:28 pm

Re: Dialing in new boat..

Postby Prototype » Sun Nov 12, 2017 4:00 pm

southern safaris wrote:
Prototype wrote:The Jx is just as dead at 6k with a 268 as in the 4k range! My 2 blade likes 5200 with a 2.68.........because they are unlike any other prop I've used?
Fitting for the snap of holley 4bbl or nos but very timid everywhere else.
If they weren't so wide I'd almost say they were designed for aircraft apps!



Hey prototype can you elaborate on your findings a little more .... I'm interested on the" just as dead at 6k as 4k " part I'm tuning in a new boat right now with a 2 blade jx and been everywhere from 4600-5400 just playing with it kinda want to compare your feelings to mine so to speak, I just didn't follow you I guess on your first post (sorry I'm just a simple minded fella) most have to write real slow for me cause I don't read real fast :thumbleft:


Sure,
I've found the JX likes pitch in the mid 20's on mine with a 268! Low 20's it just spins up to burn fuel and not impressive at all. Pitching it to 30, my motor with the jx just can't handle that drag. I would think it has a relationship with torque and all the other crap like boat length and width and load, but I have a unique situation to test it under load and obstacles! I am finding the jump point/snap,,,, in the jx loaded or unloaded which I've never found in the s or ngr's.
Kwan missed my post about the jx having a power band when it grabs air. The good thing is there is only one band/shot to the jx.
Never twisted a s or ngr as high as I've twisted a jx. never had a need too. That's why I state a smooth prop through all ranges or a needy prop through limited ranges.
But it is easy on the ears regardless!!

User avatar
Prototype
Southern Airboat Member
Posts: 687
Joined: Sat Jan 26, 2013 2:28 pm

Re: Dialing in new boat..

Postby Prototype » Sun Nov 12, 2017 4:28 pm

SWAMPHUNTER45 wrote:I'm kind of puzzled with this choice of blade on a 18ft X 8ft powered by a 540 MAS

Was the JX selection something you wanted or did someone from Sensenich feel they were your best option ?

When I first heard of the proto type blades being tested was around the time I was buying my S blades and we were debating if we should hold off for the new product.

I did a lot of research on all the brands and options. Patti from Whirlwind offered a wide blade series and gave great information but my hurdle with the Whirlwind was it liked to be spun up at a lot higher rpm than my combination was purpose built for and the only other option would have been a ratio change.
The WaterWalker engineer Andrew was another great resource and the Maximus blades are a beast but again when we were discussing rpm range I was going to need to spin higher than was best for my engines longevity.
When we met with Darrin at Sensenich and discussed the need and options the S blades were a clear best choice. They had data on other boats one which was built to run the quietest possible in which the owner achieved excellent results at a incredibly low rpm far below the recommended low. Without a doubt I got a product that does what it said it would and have no regrets going with the 4 blade S configuration.

Update us on your recent blade swap.


That would be a good post! NGR'S VS JX behind a mas 540!

GreyGoose
Southern Airboat Member
Posts: 14
Joined: Sat Jun 27, 2015 2:26 pm
Location: Cove,Texas

Re: Dialing in new boat..

Postby GreyGoose » Tue Nov 14, 2017 9:49 pm

SWAMPHUNTER45 wrote:I'm kind of puzzled with this choice of blade on a 18ft X 8ft powered by a 540 MAS

Was the JX selection something you wanted or did someone from Sensenich feel they were your best option ?

When I first heard of the proto type blades being tested was around the time I was buying my S blades and we were debating if we should hold off for the new product.

I did a lot of research on all the brands and options. Patti from Whirlwind offered a wide blade series and gave great information but my hurdle with the Whirlwind was it liked to be spun up at a lot higher rpm than my combination was purpose built for and the only other option would have been a ratio change.
The WaterWalker engineer Andrew was another great resource and the Maximus blades are a beast but again when we were discussing rpm range I was going to need to spin higher than was best for my engines longevity.
When we met with Darrin at Sensenich and discussed the need and options the S blades were a clear best choice. They had data on other boats one which was built to run the quietest possible in which the owner achieved excellent results at a incredibly low rpm far below the recommended low. Without a doubt I got a product that does what it said it would and have no regrets going with the 4 blade S configuration.

Update us on your recent blade swap.

I called Sensenich to tell them what I was having built. The boat builder wanted to go with the 3 blade NGR that I had on the previous boat and I thought I needed an extra blade being that there wasn't much room to add pitch on the old boat and I was jumping up in horsepower quite a bit. Sensenich agreed that I needed to go with the four blade and told me they thought the new JX 4 blade would be a good fit and probably offer more push than the NGR. At the time it was also cheaper. At 19 degrees I could only turn the JX 4700 rpms. Maybe a three blade would have been the better choice. I did try the three blade NGR over the weekend and at the third pitch mark I was turning 5300 rpms. The boat ran good and pushed through a spot I had been hung up in with the jx. I now have a 4 blade NGR on the way. I like the idea of being able to add pitch and lower my cruise rpms for long runs. With the 3 blade there wasn't any room left to do that. Im not knocking the new JX, but I don't think I had the power to get it to the pitch it likes to be at.
18x8 LoneStar Boatworks Mas 540

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 2493
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Dialing in new boat..

Postby SWAMPHUNTER45 » Wed Nov 15, 2017 6:45 am

It sort of makes for more questions.

I prefer to run an extra blade on a gear drive boat rather than run a heavy pitched prop. That said every series of blade is different and some may work with heavy pitch better. That engine is what Blackwater runs and it should be a beast. Jason runs a tour boat and puts his engine to the test daily and has a reputation of having a boat that can drag another out of the mud. Your experiences are very different from what he has reported. Have you consulted with the builder of the engine (MAS) since most airboat engine builders know exactly what their engine will spin at a given drive ratio. Something just does not seem correct.

Jason your the resident MAS 540 expert can you offer some perspective?

jeepinocala1111
Site Supporter - I
Site Supporter - I
Posts: 1150
Joined: Mon Apr 21, 2014 5:57 pm

Re: Dialing in new boat..

Postby jeepinocala1111 » Wed Nov 15, 2017 7:11 am

I had a three blade prop on my boat I went to a 4 blade and the difference in push is day and night it pushes harder and cruises effortlessly so I guess it is kind of like putting mud tires on your truck verse regular tires you gain more traction. I will say right at the boat ramp before even getting on plane I could tell I did the right thing. Another thought is when I went into Sensenich Propeller's store I noticed a no brainer advertisement telling you the horse power to blade selection so I will only say some boat builders need to pay attention because your screwing the pooch on prop selection :)

GreyGoose
Southern Airboat Member
Posts: 14
Joined: Sat Jun 27, 2015 2:26 pm
Location: Cove,Texas

Re: Dialing in new boat..

Postby GreyGoose » Wed Nov 15, 2017 2:53 pm

SWAMPHUNTER45 wrote:It sort of makes for more questions.

I prefer to run an extra blade on a gear drive boat rather than run a heavy pitched prop. That said every series of blade is different and some may work with heavy pitch better. That engine is what Blackwater runs and it should be a beast. Jason runs a tour boat and puts his engine to the test daily and has a reputation of having a boat that can drag another out of the mud. Your experiences are very different from what he has reported. Have you consulted with the builder of the engine (MAS) since most airboat engine builders know exactly what their engine will spin at a given drive ratio. Something just does not seem correct.

Jason your the resident MAS 540 expert can you offer some perspective?

Is he running the 2.3:1 belt drive? I'd be curious to know what pitch he's running also. MAS has 5500 as the max rpm on my build sheet but advertised this motor as being over 750 hp. At 5500 its making 735.3hp. It doesn't break 750 until 5900 and at 6300 shows 761.4
18x8 LoneStar Boatworks Mas 540

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 2493
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Dialing in new boat..

Postby SWAMPHUNTER45 » Wed Nov 15, 2017 5:03 pm

I think he has a 2.55 gear box so the ratios are close.

Certainly a 2.55 is a bit better than a 2.3 with your dyno data.

User avatar
kwanjangnihm
Site Supporter - IV
Site Supporter - IV
Posts: 1722
Joined: Sat Mar 30, 2013 8:23 pm
Location: Bartow FL

Re: Dialing in new boat..

Postby kwanjangnihm » Wed Nov 15, 2017 7:42 pm

ladyblackwater wrote: I can tell you that if you go with anything over a 2.5 on a boat as big as yours you will definitely be unhappy. The big boats don't like big ratios. With your HP and torque I would go with a 2.5 ratio. I've played with many ratios on the same hull with 3 different motors. My 383 liked the 2.3 with a 3 blade Whisper tip EX. My 496 liked the 2.5 better then the 2.3 running 3 blade Superwide Whisper Tip. My 555 big block likes the 2.5 spinning a 4 blade Superwide Whisper Tip. The 2.6 was a bust with all motors. All these test were done on a 18' X 8' Alumitec Hull. So you know if you went with a 2.6 and a 4 blade Superwide you will be way over propped. Gerald is running a 500+hp Waterthunder with a 2.6 OX box with a 4 blade Whisper Tip EX and his boat is over propped. If you are going to only run up to about 5400 rpm (which is a great idea) my choice would be a 2.5 with a 84" 3 blade Whisper Tip EX.
" I don't care who you are back in the world, you give away our position one more time, I'll bleed ya, real quiet. Leave ya here. Got that? "

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 2493
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Dialing in new boat..

Postby SWAMPHUNTER45 » Fri Nov 17, 2017 6:47 am

Great info Jason

I find it interesting to note he reported he had the JX blades spinning at 5400 rpm then added more pitch to almost the 2 mark bringing them down to 4700 rpm. He ran those blades in a good pitch range but was just not getting the push he needed. Sounds based on your testing a ratio closer the 2.55 would be a benefit.

User avatar
Prototype
Southern Airboat Member
Posts: 687
Joined: Sat Jan 26, 2013 2:28 pm

Re: Dialing in new boat..

Postby Prototype » Fri Nov 17, 2017 8:02 pm

ladyblackwater wrote:Swamphunter I agree that I think he would be better served with the 2.5 ratio and then keep the 4 blade JX. It makes sense to me that it didn't do good/best when he was turning 5400 because he didn't have enough blade angle/pitch to suit the blade. What is crazy is when he pitched them to only turn 4700 and it didn't perform well. The blade was at a great angle/pitch, the motor rpm was over the point of where the HP andtorque cross each other and he was just under the 700hp at 4700 rpm. This is leeming me to believe that there isn't something quite right with the boat set-up.



The Jx is a whole new prop! I'd like to say beast but can't!
I can say it likes power and it peaks at very limited ranges if your willing to find them. Almost build your motor to it vs the normal reverse way.
First prop I've owned that without serious testing a owner could leave 50 hp behind

GreyGoose
Southern Airboat Member
Posts: 14
Joined: Sat Jun 27, 2015 2:26 pm
Location: Cove,Texas

Re: Dialing in new boat..

Postby GreyGoose » Fri Nov 17, 2017 10:32 pm

Prototype wrote:
ladyblackwater wrote:Swamphunter I agree that I think he would be better served with the 2.5 ratio and then keep the 4 blade JX. It makes sense to me that it didn't do good/best when he was turning 5400 because he didn't have enough blade angle/pitch to suit the blade. What is crazy is when he pitched them to only turn 4700 and it didn't perform well. The blade was at a great angle/pitch, the motor rpm was over the point of where the HP andtorque cross each other and he was just under the 700hp at 4700 rpm. This is leeming me to believe that there isn't something quite right with the boat set-up.



The Jx is a whole new prop! I'd like to say beast but can't!
I can say it likes power and it peaks at very limited ranges if your willing to find them. Almost build your motor to it vs the normal reverse way.
First prop I've owned that without serious testing a owner could leave 50 hp behind

I probably should of played with the pitch a little more before I gave up on it. To me, it sounds like you cant go wrong with the S blade and a 2.5 on a BBC. Wish I would of researched that a little more before I ordered the boat.
18x8 LoneStar Boatworks Mas 540

GreyGoose
Southern Airboat Member
Posts: 14
Joined: Sat Jun 27, 2015 2:26 pm
Location: Cove,Texas

Re: Dialing in new boat..

Postby GreyGoose » Fri Nov 17, 2017 10:52 pm

ladyblackwater wrote:Swamphunter I agree that I think he would be better served with the 2.5 ratio and then keep the 4 blade JX. It makes sense to me that it didn't do good/best when he was turning 5400 because he didn't have enough blade angle/pitch to suit the blade. What is crazy is when he pitched them to only turn 4700 and it didn't perform well. The blade was at a great angle/pitch, the motor rpm was over the point of where the HP and torque cross each other and he was just under 700hp at 4700 rpm. This is leeming me to believe that there isn't something quite right with the boat set-up.

Im not sure that the blade was at a great angle/pitch even at 4700. Some are saying it doesn't come alive until after the 20 mark. The boat was fast on the water and had great acceleration/ cruise numbers so I cant say it didn't perform well, it just didn't run dry ground as well as I hoped. After running the NGR, I know there isn't a problem with the way the boat is set up.
18x8 LoneStar Boatworks Mas 540

GreyGoose
Southern Airboat Member
Posts: 14
Joined: Sat Jun 27, 2015 2:26 pm
Location: Cove,Texas

Re: Dialing in new boat..

Postby GreyGoose » Fri Nov 24, 2017 8:57 am

Update- I got the 4 blade NGR on the boat and it runs great. Max rpm at the 2 mark is around 5200-5300. I definitely think this is a much better prop for my set-up. Runs a lot quieter and seems to push dry ground better. I would've liked to try the JX with the 2.5 but I'm happy with the way the boat runs now.
18x8 LoneStar Boatworks Mas 540


Return to “Airboat Talk”

Who is online

Users browsing this forum: No registered users and 41 guests