Propeller for max IV

[seanno2]

Axle Torque

I have my propeller design complete!!! You guys are going to love this when I'm done with it. Now I need to order my parts! I'm going to be using a 12 volt electric clutch and need to know how much torque is on my axle. I have an 18HP Briggs installed. I looked through the manual and it doesn't specify a torque value. Would appreciate some help please.

[Mike]

I have my propeller design complete!!! You guys are going to love this when I'm done with it. Now I need to order my parts! I'm going to be using a 12 volt electric clutch and need to know how much torque is on my axle. I have an 18HP Briggs installed. I looked through the manual and it doesn't specify a torque value. Would appreciate some help please.

Torque is around 28 ft lbs at the motor.

Edit: I just googled it and got the following link which says it is 26 ft lbs: http://www.grainger.com/product/BRIG...s-Engine-1TKD9

[seanno2]

Torque is around 28 ft lbs at the motor.

Edit: I just googled it and got the following link which says it is 26 ft lbs: BRIGGS & STRATTON Gas Engine,18 HP,3600 RPM,Horizontal - Gasoline Engines - 1TKD9|356447-3079-G1 - Grainger Industrial Supply

Does the T-20 Reduce that at all though?

[Mike]

Does the T-20 Reduce that at all though?

It doesn't reduce it, it increases it. The gear ratio of the T20 is 6.25:1. You should calculate your full gear reduction through the T20, the CVTs and the sprockets and then multiply that gear ratio by the torque of the motor. If I remember correctly, on my Max IV, the final gear ratio was something like 15:1 or 16:1. So, if I were using the same motor as you, the final torque would be 28*16 = 448 ft lbs. at the axles assuming no losses and a 1:1 ratio between the CVTs which may vary depending on the CVTs you have.

It's late so don't take my word for it. Use the search and you should be able to confirm or correct the numbers I posted. There are a couple of threads here on the site on similar topics. Mainly calculating gearing and speed but it will apply to torque as well.

[jerseybigfoot]

It doesn't reduce it, it increases it. The gear ratio of the T20 is 6.25:1. You should calculate your full gear reduction through the T20, the CVTs and the sprockets and then multiply that gear ratio by the torque of the motor. If I remember correctly, on my Max IV, the final gear ratio was something like 15:1 or 16:1. So, if I were using the same motor as you, the final torque would be 28*16 = 448 ft lbs. at the axles assuming no losses and a 1:1 ratio between the CVTs which may vary depending on the CVTs you have.

It's late so don't take my word for it. Use the search and you should be able to confirm or correct the numbers I posted. There are a couple of threads here on the site on similar topics. Mainly calculating gearing and speed but it will apply to torque as well.

Mike the only correction I would make to your calculation is divide it by the number of tires driven.

[Mike]

Mike the only correction I would make to your calculation is divide it by the number of tires driven.

Thanks for the correction Marc. Carrying on the previous example, make sure this is correct: At first I took 448ft lbs and divided by 6 but after thinking about the T20, I realized that you should really divide by 3 since the T20 can apply all power to one side at a time. If that is correct, the max torque one axle could see would be 448/3 = ~150 ft lbs per axle.

What kind of safety factor would you put into a system like this if you were designing it? I guess the worst case would probably be losing the chain between the 2nd and 3rd axle. In that situation, you could apply all torque to the rear axle in a Max IV but I don't know how feasible designing for that situation really is.

[seanno2]

Thanks for the correction Marc. Carrying on the previous example, make sure this is correct: At first I took 448ft lbs and divided by 6 but after thinking about the T20, I realized that you should really divide by 3 since the T20 can apply all power to one side at a time. If that is correct, the max torque one axle could see would be 448/3 = ~150 ft lbs per axle.

What kind of safety factor would you put into a system like this if you were designing it? I guess the worst case would probably be losing the chain between the 2nd and 3rd axle. In that situation, you could apply all torque to the rear axle in a Max IV but I don't know how feasible designing for that situation really is.

150FT LBS of tq it is! I'll probably buy a clutch good up to 200-250 maybe even 300 to give me some room to upgrade the motor if I ever want.

As of right now I'm probably looking at $1000-$1500 to do this dual propeller idea! Seems expensive! If it works and propels me atleast 6mph in the water I'd say money well spent!

[Mike]

150FT LBS of tq it is! I'll probably buy a clutch good up to 200-250 maybe even 300 to give me some room to upgrade the motor if I ever want.

As of right now I'm probably looking at $1000-$1500 to do this dual propeller idea! Seems expensive! If it works and propels me atleast 6mph in the water I'd say money well spent!

Please don't just use those numbers, those were just for an example. I am going off of memory on some of those and my memory is not good. Make sure you calculate the gear ratio for your specific application. You can use 6.25 for the T20 but count the teeth on your sprockets and see what the actual gear ratio is for your Max. Also look up what kind of drive ratio you have for your specific CVTs. I would hate for you to invest a good chunk of change only to realize the numbers I threw out were not true for your case, causing it to just be a waste of money.

[MAX IV Mark]

For that much money plus the work. I think I would wait and see how Dan (mightymaxIV) makes out with the 16" vendetta tires on his Max IV. They swam pretty quick in the videos Keith posted of them on his hustler. You may get close to the same speed with a easy bolt on rim and tire package for the same price without the work.

http://www.6x6world.com/forums/tire-track-wheel-talk/27010-vendetta-high-performance-aatv-tires-mudd-ox.html

[Noel Woods]

I think Max4 Mark has hit it on the head. Tires and wheels are the key to movement in the water without adding a complicated prop system and the probable immediate breakdown that will follow. Terra tires swim well, Argo tires a bit better, and Vendettas even better.

[seanno2]

For that much money plus the work. I think I would wait and see how Dan (mightymaxIV) makes out with the 16" vendetta tires on his Max IV. They swam pretty quick in the videos Keith posted of them on his hustler. You may get close to the same speed with a easy bolt on rim and tire package for the same price without the work.
http://www.6x6world.com/forums/tire-...s-mudd-ox.html

If a guy has tracks on his 6x6 those tires aren't going to help much. I'm looking to drive across a lake and drive up a river to get to a really nice duck hunting spot. Propellers would be the way to go for me. For the clutches I need the torque to find out how big my clutch needs to be if you're saying yours is roughly 150ft lbs. Then I can buy a clutch that can withstand 300ft lbs of torque. It should be just fine. I'll do the math though.

[Buzz]

super cool project, but because I'm cheap, I tend to think that a trolling outboard, maybe even an air-cooled one would be a simple choice and could also be used on another boat too. There are several logistical things you can do with a set up like this to make it easy to use even when transitioning from water to land. It's hard to beat an outboard motor, and it doesn't require your engine to be running (things happen out there). You can always get your money back out of too if you're a smart shopper! Small outboards can be had with integrated fuel tanks under the cowling.

[seanno2]

super cool project, but because I'm cheap, I tend to think that a trolling outboard, maybe even an air-cooled one would be a simple choice and could also be used on another boat too. There are several logistical things you can do with a set up like this to make it easy to use even when transitioning from water to land. It's hard to beat an outboard motor, and it doesn't require your engine to be running (things happen out there). You can always get your money back out of too if you're a smart shopper! Small outboards can be had with integrated fuel tanks under the cowling.

Outboard adds extra weight and extra gas tank unless I run a hose to the regular tank. Trolling motor adds a lot of weight with 2 extra batteries. I built a mud motor out of a trolling motor and it works good but the two batteries and trolling motor adds more weight. Plus trolling motors don't give a guy enough power while driving the mud. It moves you along but nice and slow.

My design will add less then 30lbs to my machine which will give me more gross weight to play with while in the water. I think that's the money maker right there. Less weight!

[JoeMeg]

I think Max4 Mark has hit it on the head. Tires and wheels are the key to movement in the water without adding a complicated prop system and the probable immediate breakdown that will follow. Terra tires swim well, Argo tires a bit better, and Vendettas even better.

Plus you're riding 16" Vendettas full time.

[jerseybigfoot]

Seanno7 if I were to design this, I would start from the props and work my way to the power required. There iis limited space so I don't think you will use anywhere the torque available from the axle. Also the axles spin at a very slow speed so your props would have to be very large to move sufficient water. You will also want to nozzle the props to increase your thrust as an AATV is like a barge in the water. If this was my design I build a very compact 6000 PSI hydraulic drive.