Props for 20 Hydro

[Marty Davis]

Don,
By "can't be beat", I don't mean the fastest. What I am referring to is this: When somebody asks me what would be a good prop to start with on a new 21 boat (pick one) I tell them the 1716. It's fast enough to get your heart racing, but very predictable. We have found it very easy to launch and easy to spin. You don't need a bunch of torque to get it off the bank or keep it cranking through the turns. Tony Jacuzzi took his BlackJack to a second place finish at the '04 (I think) Internats after being wet for only two weeks. He did it with a 1716, the one he's still running.

Marty,

Not to preach to the Pope, but I think you'll find that with a little downforce on a slightly deeper strut, you won't have any problems keeping a smaller diameter prop hooked up.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

DOWNFORCE ??

 

[Marty Davis]

50X69 Orlic cut is what I now have on my Nova powered BlackJack , Irwin S-pipe.Tested a number of props in Ohio at the TT and that was easily the best for me

Tim K

Please describe or show an image of the "Orlic Cut"

Marty Davis

 

[Marty Davis]

Marty,We run the 46mm 1450 on Road Runner style boats. I liked the H7 on the SGX.

How much Pitch/Cup?

Marty Davis

 

[Marty Davis]

Marty,
Currently running: H-7, H-6, H-5, & S-15's with a #2 Profile, all are running very well

on my Stealth 21 with a CMB Greenhead Valvola 21,on 65% O'Donnell Fuel, and a

really short Irwin S-pipe set at 7" or less. Boat is running 82+ MPH in really clean

water and very good air with AWESOME RPM.

Good Luck Testing,

Mark Sholund

Mark:

What is a number 2 profile. Please describe or preferably show an image.

Marty Davis

 

[Brad Christy]

Don,
By "can't be beat", I don't mean the fastest. What I am referring to is this: When somebody asks me what would be a good prop to start with on a new 21 boat (pick one) I tell them the 1716. It's fast enough to get your heart racing, but very predictable. We have found it very easy to launch and easy to spin. You don't need a bunch of torque to get it off the bank or keep it cranking through the turns. Tony Jacuzzi took his BlackJack to a second place finish at the '04 (I think) Internats after being wet for only two weeks. He did it with a 1716, the one he's still running.

Marty,

Not to preach to the Pope, but I think you'll find that with a little downforce on a slightly deeper strut, you won't have any problems keeping a smaller diameter prop hooked up.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

Brad:

I wish that was me and it was true but Bryan finished 5th in Heat racing with a DNF leading the heat and riding up a slow boats roostertail, Bryan was 2nd in Oval TT's and 3rd in SAW using the 1716. We have tried lots of props but always seem to come back to the 1716 as our best overall prop.. TJ.

Tony,

Memory eludes, sometimes. I knew there was some achievement, but the details blur over a couple years......... B)

How did the H-10 I gave you in London work out?

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

 

[Tim Kish]

50X69 Orlic cut is what I now have on my Nova powered BlackJack , Irwin S-pipe.Tested a number of props in Ohio at the TT and that was easily the best for me

Tim K

Please describe or show an image of the "Orlic Cut"

Marty Davis

I don't have the prop with me so no picture and to be honest I am not sure what he did to it .

Sorry Tim .

 

[Tofastformellow]

you guys are all forgetting the trusty old v945 mod.

lol's when you figure out the front end setup to run it properly , you will know what i mean about speed on flat water .... but it needs rounded tips to turn fast and not carry on ...

h7, h4 , 1445 all good also .

for a first time run ON A NEW MOTOR,. i would have to say a 220 PRATHER, lol'S

LOL's

Jason

 

[shoboat]

Jason,

V-945/3? Is that a custom propeller or just a cut down V-947/3?

They only run in the 90's on the S.A.W. boat. I doubt you will heat

race a V-947/3 with rounded tips though.

Marty,

The #2 Profile is the profile that you talked about in your tech

article that you have not really played with yet. Take a propeller

and grind off the back side of the trailing edge up by the tip so

from .7 radi it is perpendicular to the hub. It is close to what Tim

was running also. I do not have a camera or I would show you

the 87 MPH S-15 that I am running now. It will run 90+ in my S.A.W.

boat at 2 1/2 lbs. RTR. The key is to get your pipes shorter and turn

more RPM fellas. 7" or less on the 21 and under 9" on the 45. RPM

is the key here for speed guys, and you will never get your pipes

short with high exhaust timing numbers. So back your 180+ timings

down to 175 to 178 degrees and shorten your pipes. Your motors

will then start to rev if you know what I mean?

Great Subject Guys,

Mark Sholund

 

[AndyBrown]

at this point in time we are getting abc H10 made at 47mmto use on our novarossi's

Aaron,

FINALLY, somebody else who likes the H-10........

Thanks. Brac.

Titan Racing Components

BlackJack Hydros

H-10 family tree:

Octura 1655 was copied to make ABC 55X88 . Due to mold shrinkage the 55X88 was smaller in dia. and pitch.

I modified the 55X88 to make the ABC S-15. I further modified the S-15 to run on the 21 riggers.

Stien Tumert and I got 1st and 2nd in SAW at the 1994 IMPBA Internats in Ft.Worth with this prop. I ran 75mph and Stien ran 72. We used the same props for heat racing.

This modifed S-15 became the H-10. The first cast version was too thin and would bend easily so it never became popular.

The more recent version of the H-10 has been made thicker.

 

[AndyBrown]

Marty,
Currently running: H-7, H-6, H-5, & S-15's with a #2 Profile, all are running very well

on my Stealth 21 with a CMB Greenhead Valvola 21,on 65% O'Donnell Fuel, and a

really short Irwin S-pipe set at 7" or less. Boat is running 82+ MPH in really clean

water and very good air with AWESOME RPM.

Good Luck Testing,

Mark Sholund

Mark:

What is a number 2 profile. Please describe or preferably show an image.

Marty Davis

#2 profile is a term I coined for a cut I was making on 1400 and 1600 series props back in 1993.

The trailing edge and leading edge are cut to form a point at the tip.

 

[Marty Davis]

Marty,
Currently running: H-7, H-6, H-5, & S-15's with a #2 Profile, all are running very well

on my Stealth 21 with a CMB Greenhead Valvola 21,on 65% O'Donnell Fuel, and a

really short Irwin S-pipe set at 7" or less. Boat is running 82+ MPH in really clean

water and very good air with AWESOME RPM.

Good Luck Testing,

Mark Sholund

Mark:

What is a number 2 profile. Please describe or preferably show an image.

Marty Davis

#2 profile is a term I coined for a cut I was making on 1400 and 1600 series props back in 1993.

The trailing edge and leading edge are cut to form a point at the tip.

Yes, I am familiar with that cut. What characteristics have you seen using it. You removed a LOT of the outside of the prop where is grabs the water.

By the way, I won SAW at the Sarasota Nats with the AB designed S15. Was running 86mph getting ready for the Nats. I have often thought of trying it for heat racing, but I suspect that it is too much load. How big a diameter is the H10? Is is a little smaller than the S15?

Marty Davis

 

[shoboat]

Marty,

An H-10 is 44.38 mm

An S-15 is 50.36 mm

An H-6 is working very well on most fast 21 Hydros.

Thanks,

Mark Sholund

 

[Marty Davis]

Marty,
An H-10 is 44.38 mm

An S-15 is 50.36 mm

An H-6 is working very well on most fast 21 Hydros.

Thanks,

Mark Sholund

Mark:

What is the diameter of the H6?

Marty Davis

 

[shoboat]

Marty,

An H-6 is 46.05 mm.

Mark Sholund

 

[Marty Davis]

Marty,
An H-6 is 46.05 mm.

Mark Sholund

What is available in the 48-21mm size, that run well? I still like the larger diameter props.

I know that the H7 is a great prop, and I run them. I also like the 1450 VERY well. Others???

Guess I will have to start learning to cut down larger props....

Marty Davis

 

[AndyBrown]

Marty,
An H-6 is 46.05 mm.

Mark Sholund

What is available in the 48-21mm size, that run well? I still like the larger diameter props.

I know that the H7 is a great prop, and I run them. I also like the 1450 VERY well. Others???

Guess I will have to start learning to cut down larger props....

Marty Davis

Marty,

Work with the 1452. It has more additional pitch over the 1450 than what the math (1.4X52mm) would indicate.

Narrow the blades while maintaining the diameter. Add no cup. Be sure to thin the blades also, as they are much thicker than the 1450 and that will eat power. This will stay hooked up in the rough stuff and get you lots of speed.

 

[Preston_Hall]

RPM
is the key here for speed guys, and you will never get your pipes

short with high exhaust timing numbers. So back your 180+ timings

down to 175 to 178 degrees and shorten your pipes. Your motors

will then start to rev if you know what I mean?

So what do you do if the timing is well above 180 degress and you have a short pipe? Keep it there because you are screaming.

 

[AndyBrown]

RPM
is the key here for speed guys, and you will never get your pipes

short with high exhaust timing numbers. So back your 180+ timings

down to 175 to 178 degrees and shorten your pipes. Your motors

will then start to rev if you know what I mean?

So what do you do if the timing is well above 180 degress and you have a short pipe? Keep it there because you are screaming.

LOL Preston!! :lol:

 

[Marty Davis]

Marty,
An H-6 is 46.05 mm.

Mark Sholund

What is available in the 48-21mm size, that run well? I still like the larger diameter props.

I know that the H7 is a great prop, and I run them. I also like the 1450 VERY well. Others???

Guess I will have to start learning to cut down larger props....

Marty Davis

Marty,

Work with the 1452. It has more additional pitch over the 1450 than what the math (1.4X52mm) would indicate.

Narrow the blades while maintaining the diameter. Add no cup. Be sure to thin the blades also, as they are much thicker than the 1450 and that will eat power. This will stay hooked up in the rough stuff and get you lots of speed.

Andy:

Thanks, I will try that....

Marty Davis

 

[AndyBrown]

Marty,
An H-6 is 46.05 mm.

Mark Sholund

What is available in the 48-21mm size, that run well? I still like the larger diameter props.

I know that the H7 is a great prop, and I run them. I also like the 1450 VERY well. Others???

Guess I will have to start learning to cut down larger props....

Marty Davis

Marty,

Work with the 1452. It has more additional pitch over the 1450 than what the math (1.4X52mm) would indicate.

Narrow the blades while maintaining the diameter. Add no cup. Be sure to thin the blades also, as they are much thicker than the 1450 and that will eat power. This will stay hooked up in the rough stuff and get you lots of speed.

Andy:

Thanks, I will try that....

Marty Davis

Marty,

Once you've cleaned up the tips and narrowed a little off the front and back it should be about 51mm.