thrust bearing.....what's your take?

[keithbradley]

So the u bend stuffing tube going to the reverse motor is now the thrusting point which means it will push the boat at the apex of the bend . If your u bend is high up it will try to lift the bend if it's low it will push more evenly. A thrust bearing at the strut would eliminate any negative handling effect of a stuffing tube like this. Just saying !

I had to read this 10 times. I finally understand what you're saying. It's just not true. Don't draw an imaginary line from the prop to the motor, that is not how thrust vectoring works. Regardless of where the flex is contained and what angle it's at, the boat is being pushed relative to the axis of the prop hub, not the axis of the motor shaft or flex.

EDIT: By the way, your hypothesis would be correct if it were based on a solid shaft, because the "thrusting point" that you're imagining would be relative to the axis of the prop hub. With a flex, it's not.

[flraptor07]

I have. No matter what angle the motor is at, it not going to affect it. The prop shaft angle is what will affect it. Think about it. You could face the motor backwards. It's still going to do the same thing. The prop and shaft are pushing it straight ahead. All you need is something to stop the shaft from traveling to far in the boat if you will (collet/motor) and no matter what angle you have the motor at, your going to have forward thrust dependent upon prop angle.

Gyroscopic effect and torque does come into play slightly, I think that's where the motor angle thing came from..

[tlandauer]

I usually push cars from the driver's door with the window down so I can steer. Otherwise you might run in to something.

Now you tell me!! Hmmm, that explains all the lawsuits and insurance policy cancellations!

[keithbradley]

Gyroscopic effect and torque does come into play slightly, I think that's where the motor angle thing came from..

These things are real, but do not change based on whether we are "thrusting at the motor" or at the strut.

[flraptor07]

These things are real, but do not change based on whether we are "thrusting at the motor" or at the strut.

True..

[kfxguy]

Gyroscopic effect and torque does come into play slightly, I think that's where the motor angle thing came from..

No doubt, but probably not a huge effect on it. I could be wrong tho.

[flraptor07]

No doubt, but probably not a huge effect on it. I could be wrong tho.

That's what I said "slightly"

[rearwheelin]

I had to read this 10 times. I finally understand what you're saying. It's just not true. Don't draw an imaginary line from the prop to the motor, that is not how thrust vectoring works. Regardless of where the flex is contained and what angle it's at, the boat is being pushed relative to the axis of the prop hub, not the axis of the motor shaft or flex.

EDIT: By the way, your hypothesis would be correct if it were based on a solid shaft, because the "thrusting point" that you're imagining would be relative to the axis of the prop hub. With a flex, it's not.

Way to many beers drank

[jcald2000]

One I haven't seen any one discuss, thrust at the strut pushes nose up and thrust at the motor pushes nose down. We did all these these tests 20 years ago and pushing on a lubed ball bearing is far less drag than anything else.

[rearwheelin]

I think everyone is correct ! I'm going to try pushing with my motor mount on my new cat . I've ordered 1/4 flex and running a flex oiler . It will have thrust washers too ! If I want to run the gap or no gap I will be equipped propper . I like both ways ! lol

[ray schrauwen]

you mean at the motor right??

One I haven't seen any one discuss, thrust at the strut pushes nose up and thrust at the motor pushes nose down. We did all these these tests 20 years ago and pushing on a lubed ball bearing is far less drag than anything else.

[rearwheelin]

So is it better to push on a motor that is forward mounted in the hull or one mounted towards the rear ?

[Cooper]

Guys, for this to be better understood, imagine the stern/transom/back of boat was the prop hub. As Keith has said above this is what the mechanics of propulsion are applying to. Not having read entire post yet but just last page I think some are over analyzing this. The motor could be mounted anywhere. And again unless a straight shaft is used the motor shaft and prop hub are not one of the same in thrust direction. As far as thrust bearing, great idea but how many of them actually support load? How many are properly loaded? It's a bit tricky with a flex cable that shrinks when power applied. In my opinion the rewards of using a thrust bearing for support verses the (every motor has them built in to start with) added rotational weight to an already unbalanced shaft ( as no one has a balanced flex shaft) is just not a good choice in my opinion.

I'm only relating to higher end setups. For sport sure whatever. And unless your motor is using bushings instead of ball/radial bearings all sealed bearings support lateral load, thrust. Any of you airplane guys use thrust bearings?

[rearwheelin]

The motor could be mounted anywhere. And again unless a straight shaft is used the motor shaft and prop hub are not one of the same in thrust direction.

If your thrusting with your motor (happens when there is a space between dog and strut or (hub) ) it doesn't matter if you run flex or wire you are pushing the boat at the the spot where forward thrust is transferred . If you run a gap at the dog and it never bumps the strut with the dog the strut never acts as the forward thrust transfer spot , it's more of a prop shaft holder. If 100% of forward thrust is transferred at the strut you can draw an emaginary line between the strut and motor shaft ! Meaning pic your motor placement based on the layup you like and only difference in the "effect" on motor placement will be the motors gyroscopic effect on the boats handling and that's if you thrust at the prop hub...... Everyone confused yet ?

[montymike]

Think I will go with the less is more approach.