wrong prop

clack707
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wrong prop

Postby clack707 » Thu Oct 19, 2017 9:00 pm

i need help from you pros. i am new at the air boat world and have a 14 by 7.5 2.5 deep. set up for 350 chevy. the prop i have is a 12 by 76 stump puller. i was told it is to big to run dd that i need a 2 to 1 prop drive are a 10 by 72 supper snapper. could i get some input. thanks

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mojoe
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Re: wrong prop

Postby mojoe » Fri Oct 20, 2017 7:02 am

That is a bit big.

Do a search for 350 DD prop. This has been discussed at length and there are quite a few that work.
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kwanjangnihm
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Re: wrong prop

Postby kwanjangnihm » Fri Oct 20, 2017 8:20 am

before spending money on a gearbox and moving your rigging, try a 72" signature series or sensenich Q :thumbleft:

is the motor stock? can you post a photo of your rig?
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Deano
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Re: wrong prop

Postby Deano » Fri Oct 20, 2017 11:23 am

Where are you at? Somebody near you may have one that you could try.

Be aware that in any case, that is a lot of boat for a 350 while being a DD.
It will demand a better match than what you currently have to see it's potential as a DD.
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Scotty1
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Re: wrong prop

Postby Scotty1 » Fri Oct 20, 2017 1:39 pm

:rebel: my self personally I would go with 70 inch whisper tip Q. I RAN THE 72 AND THE 70 just by changing hubs and could get more rpms out of the 70 inch and a little more pitch which made the difference for me. but a belt drive 1.77 to 1 and 74inch ngq would be the ticket.IMO :rebel:

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Re: wrong prop

Postby clack707 » Fri Oct 20, 2017 6:45 pm

i have a 350 bore 40 over with carb and RV cam. I am in north east TX at 75643.this was my first try at this I am a new member. thanks so much for your help. I just came in and need to eat and i will go over all you have sent me. thanks again and i will be back on this again.

clack707
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Re: wrong prop

Postby clack707 » Fri Oct 20, 2017 8:52 pm

I came up with enough money to buy this boat and prop with hub and it about cleaned me out. I am 70 and not much coming in. I am rebuilding the motor with what I can scrape up. I just wanted to help the people that get flooded out like when the Red floods up here around Shreveport and the people in the south like Houston. IF anyone has are knows someone who might do some trading maybe I can get this thing together for the next flood. I thank you for your input I have read it all several times and will try to go in that direction. Thanks again

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Deano
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Re: wrong prop

Postby Deano » Fri Oct 20, 2017 10:19 pm

Unfortunately, my being in Central Florida and using a different brand of props, I'm not able to help you directly.

Were I you, I would call Patty @ Whirlwind and explain to her what you have, and what you are wanting to do. Their
number is (619) 562-3725. She is very knowledgeable and nearly always a big help. Really, all you minimally need is
the correct set of blades to re-use your current hub. She will be able to tell you which blades will fit those parameters,
so you will know what your options are going forward and/or what you are looking for to accomplish that end.
There could be a possibility they have taken a set of blades in on trade that you could use.

That type of possibility may also exist at American Airboats in Orange, Tx. (409) 883-7725 :dontknow:

Selling your current blades may allow you to recoup most of that additional expense. Best of Luck . . .
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but it is not the path to knowledge; it has no place in the endeavor of science."
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Scotty1
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Re: wrong prop

Postby Scotty1 » Sat Oct 21, 2017 8:52 am

:rebel: You could probably go with wood wide prop like a72L X 32 OR 34 PITCH OR 70L X 34 OR 36 WOULD BE YOUR CHEAPEST WAY. IMO ONLY :rebel: FOR MAYBE 5 TO 6 HUNDRED

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Re: wrong prop

Postby clack707 » Sat Oct 21, 2017 6:10 pm

I see why this Southern Air boat group is so great. The nice people on here are such a great help to us first timers. I am checking out all the potions you have given me. Once again thank you so much. If I stay at it and with your help I think I can make it.

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Re: wrong prop

Postby ercalabria » Sun Oct 22, 2017 10:58 am

you, might try getting on facebook and then go to Red River Airboat group, or BRAB (Brazos River Air Airboats), or Southeast Airboat association. Most are members here on Southern Airboat also. The prop you have is a good match for 350 with 2/1 belt drive and should be easy to barter/trade out. I used to run 350 DD and used 72/38 and 72/40 wood prop for years before we could afford composite. Check out the classifieds here on SA also. Have you tried selling your composite prop yet ? How much ?
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clack707
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Re: wrong prop

Postby clack707 » Sun Oct 22, 2017 2:55 pm

Thanks for your reply. I will try face book now. I am slowly getting a knowledge of this with every ones help. Great of you guys to take your time to help me. thanks again.

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Re: wrong prop

Postby clack707 » Fri Oct 27, 2017 3:35 pm

I have decided to try to find a 2 to 1 belt drive if some one has one. I think that is my best rout and use the stump puller I have. I think that will work good. what do you pros think?

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Deano
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Re: wrong prop

Postby Deano » Fri Oct 27, 2017 4:56 pm

Considering the desired end result, there is no question that is the preferred path to take if you have the means. :thumbleft:

Given that course of action, the next biggest consideration to be aware of is that your cam
needs to operate in the same range where your prop is the most productive using the chosen gear.

Based on info in this following thread, it looks like your max prop speed should be 2700 rpm:
https://southernairboat.com/phpBB3/viewtopic.php?f=133&t=68098&p=661049&hilit=the+older+Stump+Puller+blade+series#p661049

With a 2:1 reduction, that implies you would want your cam to enable you to spin 5400 rpm.
That's not to say that need to spin it that fast, but you will probably want to retain that option.

Does the engine already have an RV cam, or was that just the plan for going with direct drive?
If so, perhaps a 1.77 gear would be a better match if you don't want to change the cam.

In any case, there are improved results to be had by properly matching your engine RPMs with your prop's power band.
Cam choice and/or gear selection are the two primary and fundamental means of attaining that end.
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
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clack707
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Re: wrong prop

Postby clack707 » Fri Oct 27, 2017 8:31 pm

I already put the R/V cam in the motor. was that a mistake ?

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Deano
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Re: wrong prop

Postby Deano » Sat Oct 28, 2017 9:25 am

I am hesitant to say that was a mistake, but the odds are numerous that it will not be optimal for a 2:1 reduction.
What is the advertised RPM range of the cam you currently have?

If it is ???? -> 4800 RPMs, a 1.77 gear ratio would be a better RPM fit for your prop. However, be aware that a smaller engine
will benefit from all the gear and RPMs you can give it; hence, that gear ratio is typically used with a big block for that reason.

Given that you are looking to buy a used belt drive, I would kind of view worrying about the cam like putting the cart
before the horse. You don't know what gear ratio you will end up with, so the best cam for that gear remains undefined.

If you find a deal on a 2:1 then you would likely be better off with a different cam,
because chances are great that an RV cam is not going to pull all the way to 5400 rpms.

If you find a deal on a 1.77:1, the cam you have may work, depending on it's rpm range. In that case, I would
likely try what you have and confirm that it needed changed before I worried about it . . . hopefully it would not.
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
- Carl Sagan

clack707
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Re: wrong prop

Postby clack707 » Sat Oct 28, 2017 1:20 pm

your sure are a lot of help to me. Don't know what I would do other than make more mistakes with out your advice. thanks again for your help. I will keep trying to come up with a prop drive that will work I hope. If it comes to it I will change the cam. Any one need a new R/V cam HA HA. Thanks again.

clack707
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Re: wrong prop

Postby clack707 » Mon Nov 06, 2017 8:20 pm

I been looking everywhere for a drive and seem to find one just after it was sold. I am hoping someone out there will see this that has one they would sale. Need one for a Chevy that is close to a 2 to 1. If you have a drive please please respond. thank you.

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Re: wrong prop

Postby One Eyed Gator » Tue Nov 07, 2017 8:03 am

I may have missed it above But:
DD = Left-handed rotation
Belt drive = left-hand rotation
Gear drive = right-hand
So what rotation is your super snapper?

Also someone above mention they ran a 72x38 wood prop on a 350 dd he did not say but it was probably a stick prop (narrow blade) I ran a 72 x38 on a DD caddy for a long time it was a wide blade model.Another blade I tried on may caddy was a 74" super snapper, really did not care for it.

While you have gotten some good advice there are a lot on small details to consid

clack707
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Re: wrong prop

Postby clack707 » Thu Nov 09, 2017 8:14 pm

sorry about my like of info. I have a stump puller 3 blade 12 by 76 . It turns counter clockwise standing behind the boat. I been looking for a H 3 belt drive. I was told I need a 2.3 to 1 or maybe a 2.0 to 1. I am sorry about my like of knowledge but I got to learn some way and it is with the help of you pros that keep me in line. Thanks for your help. I really need your input. Sorry about taking so long to answer you but my 93 year old mom is in the nursing home and I have to take care of her needs. Look forward to hearing from you.

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Re: wrong prop

Postby KC5AKB » Sun Mar 11, 2018 5:05 pm

Hope Mom is doing good . How is the Airboat coming along?
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