21 Hydro Propellers

[shoboat]

Boaters,

As you might know I run 21 hydros mostly, and I do quite a

few propellers for them all. Recently, I have had a lot

of requests for different 21 hydro propellers. Anyone care to

share what is working for them currently? I would appreciate

if we can keep this topic on track so we can all help each other

with a better set up. Pictures can be very helpful if you care to share.

The H-4 @3.21" & H-6 @3.46" have been getting a lot of attention lately.

Thanks For Reading,

Happy Holidays,

Mark Sholund

Props-4-U

 

[BB Mods's]

Id post what I'm running... but then again, you already know

 

[Ron Zaker Jr]

H7 bag

H10 bag,moderate rough water

H5 on white cap water

1650,17 degree rake and de tounged

1450,with 3 .062 holes in tongues full blade

1450,barr cut and pitched to whatever the needle will take.

Recent findings

S-15 bag, full blade

1650 bag, full blade

All of the above are for heat race trim.

Ron Jr

 

[shoboat]

Ron,

I run an S-15 with #2 profile and I've had great results.

You run the 1650 rather high on the strut or as deep as others?

Nova power correct? What pipe are you currently running?

Thanks,

Mark Sholund

 

[Ron Zaker Jr]

Ron,
I run an S-15 with #2 profile and I've had great results.

You run the 1650 rather high on the strut or as deep as others?

Nova power correct? What pipe are you currently running?

Thanks,

Mark Sholund

Same strut setting,in fact basically non adjustable at the moment. Yes Nova L/S and OPS 3280/ CD Machine silencer.

 

[Marty Davis]

Ron,
I run an S-15 with #2 profile and I've had great results.

You run the 1650 rather high on the strut or as deep as others?

Nova power correct? What pipe are you currently running?

Thanks,

Mark Sholund

Same strut setting,in fact basically non adjustable at the moment. Yes Nova L/S and OPS 3280/ CD Machine silencer.

Ron:

That new boat must be flying with a full blade 1650. Is the reason that you can run that blade the strut assist? Do you get hop with the S15 or the 1650 in rough water?

I am only able to turn a 1450 Barr Cut

 

[Tony Jacuzzi]

ABC 1716 is by far the best prop on our Blackjack for us. Heat races between 66-69 MPH does nothing dumb, easy launch, good throttle and its a lot easier on our MAC than some of the others mentioned... Tony J

 

[Ron Zaker Jr]

Ron,
I run an S-15 with #2 profile and I've had great results.

You run the 1650 rather high on the strut or as deep as others?

Nova power correct? What pipe are you currently running?

Thanks,

Mark Sholund

Same strut setting,in fact basically non adjustable at the moment. Yes Nova L/S and OPS 3280/ CD Machine silencer.

Ron:

That new boat must be flying with a full blade 1650. Is the reason that you can run that blade the strut assist? Do you get hop with the S15 or the 1650 in rough water?

I am only able to turn a 1450 Barr Cut

Hi Marty,

No hop yet. The water was rougher than normal but not extremely rough. It does run very well. I think it is the strut assist helping out.

 

[DON MAHER]

Hi Marty,

No hop yet. The water was rougher than normal but not extremely rough. It does run very well. I think it is the strut assist helping out.

OK, I'll bite. What is "strut assist"????

Don :blink:

 

[BB Mods's]

It would also be pertinent to include your nitro % and relative altitude.

Like me, this time of year we see about 3000' corrected altitude (2550' nominal) 50% nitro, timing's are based on one of Marty's LS nova profiles with a slightly lower blow down of 28.8* and a 8mm venturi carb, prop is H-4 done by Mark, 44.59mm OD still fat on the needle trying to ease this new p/s into life, and seeing a impressive 50+ mph with the strut 3/16" off the board, and spewing fuel out the pipe, head temps are a constant 185*f measured at the side of the head button (nova RX21 SS2) pipe temps in the cool 480*f range during the runs.

After the engine is ready for leaner setting's my ideal temps will be 215*f on the button, and 585~610*f on the pipe during a run. 325*f or so on the shore (pipe temp) and 210*f on the button.

 

[Marty Davis]

It would also be pertinent to include your nitro % and relative altitude.

Like me, this time of year we see about 3000' corrected altitude (2550' nominal) 50% nitro, timing's are based on one of Marty's LS nova profiles with a slightly lower blow down of 28.8* and a 8mm venturi carb, prop is H-4 done by Mark, 44.59mm OD still fat on the needle trying to ease this new p/s into life, and seeing a impressive 50+ mph with the strut 3/16" off the board, and spewing fuel out the pipe, head temps are a constant 185*f measured at the side of the head button (nova RX21 SS2) pipe temps in the cool 480*f range during the runs.

After the engine is ready for leaner setting's my ideal temps will be 215*f on the button, and 585~610*f on the pipe during a run. 325*f or so on the shore (pipe temp) and 210*f on the button.

Tommy:

How are you measuring the pipe temp during the run? Also where are you measuring the pipe temp?

These are VERY IMPORTANT measurements that we have been looking for for pipe design. Can you measure the pipe temp inside the pipe in any way? If you are using a thermocouple, can you place it in the largest part of the pipe right in the middle of the pipe? That would be very important information.

Marty Davis

 

[Terry Keeley]

ABC 1716 is by far the best prop on our Blackjack for us. Heat races between 66-69 MPH does nothing dumb, easy launch, good throttle and its a lot easier on our MAC than some of the others mentioned... Tony J

And them aint "keyboard" MPH, I was holdin' the gun...

 

[SayMikey]

ABC 1716 is by far the best prop on our Blackjack for us. Heat races between 66-69 MPH does nothing dumb, easy launch, good throttle and its a lot easier on our MAC than some of the others mentioned... Tony J

And them aint "keyboard" MPH, I was holdin' the gun...

Keep talking boys im taking notes. Got a 21 sgx coming and i need this stuff. So with the Nova Rossi a 3280 is the best choice? Length? How about a Irwin short pipe? Internal stinger? Very good stuff esp with launchabuility issues with props. Looking forward to joining you guys next season......Mike

 

[BB Mods's]

K type thermocouple in the center weld, I built a small 8051 based controller that logs raw 16bit hex data for recording temps, Iv got some pre-made K type probes that screw in the pipe (drill/tap the center weld) I only plan to use the data to tune my engine, not sure how you build a pipe around it, but if you send a pipe, ill build a controller with 5 or 6 I/O lines so you can run like 4 internal probes and 2 external, though with coated pipes and pipes that get cooled by air running over them, i never had any luck with accurate external temp log's, they always had cold dips from water spray/air cooling it down.

Mike, the 3280 might not be the best, but its a **** hard pipe to beat. I like the old AB 21 nitro pipe! to be honest... where im at, i cant see any difference between the 3280 and the 21 nitro pipe.

The one Iv been playing with as of late is the novarossi black pipe from glen, hold heat super well, and the RPM's are nothing to laugh at, Thom Hammer runs that exact pipe on his record holding A mono....

Wont it be a grand day when we have it "all figured out"

 

[Marty Davis]

K type thermocouple in the center weld, I built a small 8051 based controller that logs raw 16bit hex data for recording temps, Iv got some pre-made K type probes that screw in the pipe (drill/tap the center weld) I only plan to use the data to tune my engine, not sure how you build a pipe around it, but if you send a pipe, ill build a controller with 5 or 6 I/O lines so you can run like 4 internal probes and 2 external, though with coated pipes and pipes that get cooled by air running over them, i never had any luck with accurate external temp log's, they always had cold dips from water spray/air cooling it down.


Mike, the 3280 might not be the best, but its a **** hard pipe to beat. I like the old AB 21 nitro pipe! to be honest... where im at, i cant see any difference between the 3280 and the 21 nitro pipe.

The one Iv been playing with as of late is the novarossi black pipe from glen, hold heat super well, and the RPM's are nothing to laugh at, Thom Hammer runs that exact pipe on his record holding A mono....

Wont it be a grand day when we have it "all figured out"

So, you are measuring the temps in the center of the wave at the largest part of the pipe? That is the correct place to get the temp for designing pipes.

What nitro are you running? What prop (heavy, medium or light load on the engine)?

If you really want to tune youe engine based on pipe temps, you should tie it to a mixture control so that you can maintain about the same temp around the course. You will then get amazing performance.

 

[Duck899]

CMD prepped H-4 @ 3.3".....7 year old N/R.....Irwin pipe.

 

[BB Mods's]

Don't need to, my internal temps never change more then 5* -+, I will be testing a steel pipe shortly, header is made to the pipe. its based on the 3280 since the angles are easy to reproduce.

what I need now is for you to prep one of my sleeves

 

[Don Ferrette]

H7 bagH10 bag,moderate rough water

H5 on white cap water

1650,17 degree rake and de tounged

1450,with 3 .062 holes in tongues full blade

1450,barr cut and pitched to whatever the needle will take.

Recent findings

S-15 bag, full blade

1650 bag, full blade

All of the above are for heat race trim.

Ron Jr

If anyone's interested I have a CMDi prepped 1650 for sale on the prop swap page.

 

[shoboat]

Don,

What were you running on your 21 Blackbird before you sold it?1450?

Curious?

Thanks,

Mark Sholund

 

[Don Ferrette]

Don,
What were you running on your 21 Blackbird before you sold it?1450?

Curious?

Thanks,

Mark Sholund

Yup, I think that's it, was the prop that you did for it. B)