set-up for a counter rotating surface drive on a twin

[cougarman]

This is a tough one.

We are looking at a twin installation with our new drive.

Now for the combination of the blackhawk/inboard or outboard combo thread with a little twist.

What will be faster, better handling, ect...

1) front props spinning inboard, rear props outboard

2) front props spinning outboard, rear props spinning inboard.

3) different ratio front and rear with different pitch to match speed or same ratio/pitch

4) # of blades front/rear 3x3 4x4 5x5 6x6 7x7 3x4 3x5 6x3

5) diameter


pat W

Nice Project Pat,

How much power can the drives handle ?

Thanks
Jon

[Ratickle]

What i never understood is why a LH against the tourque in a LH (standard)motor ???
Does not make any sense to me.
If u look from the back of the boat all the standard engines turn left,,so why would u want a LH drive on there ????
If that would be the case ,all the single engine boats build would have a LH drive on it ?! NO ????
My single 32 with 800HP and a SSM has a RH drive ,the boat is very light and it does not lean to either side at all.

You're right, I guess. I was thinking reversed.

[Ratickle]

Now I gotta think. Hurts......

Does engine torque go opposite of rotation under acceleration?

[DAREDEVIL]

Now I gotta think. Hurts......

Does engine torque go opposite of rotation under acceleration?

I would say NO,,,since the only thing rotating in 1 direction is the crank ,,the pistons are on either side ,,same ,,so no weight ?!

mmmhhhhhh,,

[shifter]

What i never understood is why a LH against the tourque in a LH (standard)motor ???
Does not make any sense to me.
If u look from the back of the boat all the standard engines turn left,,so why would u want a LH drive on there ????
If that would be the case ,all the single engine boats build would have a LH drive on it ?! NO ????
My single 32 with 800HP and a SSM has a RH drive ,the boat is very light and it does not lean to either side at all.

Sorry my bad I meant RH... I always get that backwards because I am Left Handed.

The torque leans the boat to the right under accelleration so the impact of the blade to the water counters the action making it somewhat balanced.



We designed the drives to take big power as well as being very efficient. It will run very well with light power. The lead shaft is 110mm in diameter. the rear shaft is the same as a #6....see photo.
kind of gives you an idea we are not playing around.

pat W

[DAREDEVIL]

Sorry my bad I meant RH... I always get that backwards because I am Left Handed.

The torque leans the boat to the right under accelleration so the impact of the blade to the water counters the action making it somewhat balanced.



We designed the drives to take big power as well as being very efficient. It will run very well with light power. The lead shaft is 110mm in diameter. the rear shaft is the same as a #6....see photo.
kind of gives you an idea we are not playing around.

pat W

Wonder how my Aero-Tek would run with this ??!! mhhhhh.
Also handling around the dock,,,,,whats the turning point from lock to lock on it in inches ???

We could make a nice WEISSMAN raceboat,,,u know ?! LOL
Back of my boat ,,,see pic.

[Offshoredrillin]

The lead shaft is 110mm in diameter. the rear shaft is the same as a #6....see photo.
kind of gives you an idea we are not playing around.

pat W

thats the same as a blackhawk, we use a 6 lock nut on them. is throttle up making props for them? I have a brand new set of 27's for a blackhawk, never been on a boat.

[DAREDEVIL]

Blackhawk ?????????? mmmmmmhhhh

[shifter]

I like you aerotek the way it is. Why do you have the water pick up on the right side? How is your slip #? Find one of my dry-sump #4 drives in the UAE. We did 10 of them. Contact victory team.

I was thinking of a 46 ft full canopy single drive center rudder raceboat. something that can run some real mph.

The steering is 40 deg total 20 left 20 rt. Docking is always better with a DP drive.

Throttle Up is making all my props from now on. I have had great results with them so far.

I did not look at the blackhawk props when I started this design. I wanted to be able to use the bravo type props with the internals knocked ut and splined so people like Throttle Up could use the tooling for the castings they already have thus cutting cost. That is why we went with the 26 spline on the rear for the hp version. We can also run the bravo type 19 spline for the economic version of the drive.

The way I looked at it is:
single prop bravo smallblock baseline package
then dual prop up to 1000hp with bravo type thickness props
single high performance
dual prop high performance. with HP thickness props
stern drive
fixed trimmable no skeg with a center rudder.

Lots of combinations

pat W

[DAREDEVIL]

I like you aerotek the way it is. Why do you have the water pick up on the right side? How is your slip #? Find one of my dry-sump #4 drives in the UAE. We did 10 of them. Contact victory team.

I was thinking of a 46 ft full canopy single drive center rudder raceboat. something that can run some real mph.

The steering is 40 deg total 20 left 20 rt. Docking is always better with a DP drive.

Throttle Up is making all my props from now on. I have had great results with them so far.

I did not look at the blackhawk props when I started this design. I wanted to be able to use the bravo type props with the internals knocked ut and splined so people like Throttle Up could use the tooling for the castings they already have thus cutting cost. That is why we went with the 26 spline on the rear for the hp version. We can also run the bravo type 19 spline for the economic version of the drive.

The way I looked at it is:
single prop bravo smallblock baseline package
then dual prop up to 1000hp with bravo type thickness props
single high performance
dual prop high performance. with HP thickness props
stern drive
fixed trimmable no skeg with a center rudder.

Lots of combinations

pat W

Sounds cool.
Pat, my slip # is around 20% and i tried to contact team victory but got nothing,,,the drysump would be cool.

Ps.: the pickup was there when i got the boat,,waterpress is fine ~ 18 psi @ WOT.

[shifter]

The water pick up is making a mess out of the water going to the prop. I would get it over to the center so it will get the bullet.. It is worth a try.

I will see if they have any more #4's.

pat W

[DAREDEVIL]

The water pick up is making a mess out of the water going to the prop. I would get it over to the center so it will get the bullet.. It is worth a try.

I will see if they have any more #4's.

pat W

U think the PU matters that much ??? mmmmhhhh.

next time i have the engine out i try it,,because i need to move the drainplug and stuff.
Thanks.

[shifter]

Make the pickup horseshoe shaped so it clears the drain plugs. Water does not like 90 deg changes in direction. The pick up you are running causes lift and lots of drag and aeration to the water that gets in.

pat W

[DAREDEVIL]

Make the pickup horseshoe shaped so it clears the drain plugs. Water does not like 90 deg changes in direction. The pick up you are running causes lift and lots of drag and aeration to the water that gets in.

pat W

What do u mean by horseshoe shaped ??? Picture please.

[shifter]

Horseshoe come out parallel with the bottom and loop back in clearing the drain plugs.



Here is a quick sketch.



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pat W

[DAREDEVIL]

Horseshoe come out parallel with the bottom and loop back in clearing the drain plugs.



Here is a quick sketch.



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pat W

LOL,,,but ok i get it.