Real Time Thrust Tests with Complete Boats

Hey big, I can't wait to see some of the saber results for the ac crew. Especially the 5 blade test. i have the 72" ngh so I know it pushes m boat well. One other question do you run a crew for pike? I work for a co-op.
 
Saber Testing is still a few more weeks out. We are still planning to test 4, 5, and 6 blade setups when we do.

PM sent about other question .....
 
The 540 shows numbers at 950 with a 3 blade at #2. the 520 shows less thrust #'s at the same pitch but the props are set the same with the same RPM. I don't understand?
 
fl cracker said:
The 540 shows numbers at 950 with a 3 blade at #2. the 520 shows less thrust #'s at the same pitch but the props are set the same with the same RPM. I don't understand?
Click to expand...

This also has us scratching our heads to. All we can figure out is the air flow to the prop is disturbed. Its odd because the 0540 boat looks to have a more of a restrictive air flow.
 
Are you guys going to try the Q prop on the 540 boat? Like to see the difference between the 2 props on the same boat. I have a 3 blade NGH on a 540 and by the seat of the pants I feel it has more over all push than my old 2 blade Q but I thought my Q had better low end push less RPM's to move on the ground. But the Q to me felt like once you got to a point say 2700rpms it just fell off where I feel that the NGH keeps on pushing. Thanks for all that you'll have put in to this!! :cheers:
 
maybe ..... one engine is a little weak ... if you dont dyno you dont know ... except what the prop will blow works jsut like a dyno .. air brake vs. water brake .. same results ... tells ya about power ... my opinion anyways
 
hogdoggin said:
Are you guys going to try the Q prop on the 540 boat? Like to see the difference between the 2 props on the same boat. I have a 3 blade NGH on a 540 and by the seat of the pants I feel it has more over all push than my old 2 blade Q but I thought my Q had better low end push less RPM's to move on the ground. But the Q to me felt like once you got to a point say 2700rpms it just fell off where I feel that the NGH keeps on pushing. Thanks for all that you'll have put in to this!! :cheers:
Click to expand...

Before the 72" three blade NGH we had a 2 blade 72" Q on the 0540 boat and to be honest the difference was night and day. Im not knocking the Q because I know they are very good props but on this boat the 3 blade NGH just performs better. We didn't thrust test the 540 with the Q because we ran out of time and I'm not sure if we will because the next testing will be with Sabers and I'm sure that will be time consuming.
 
I have a correction to make:

I stated earlier that we verified the tach on every boat. We did put the digital timing light on every boat but.......the 520 wouldn't give us a reading for some reason. Therefore the RPM is unverified on that boat. Maybe the tach is off causing some of the confusion??

Sorry for the oversight.
 
Roxy7430 said:
I have a correction to make:

I stated earlier that we verified the tach on every boat. We did put the digital timing light on every boat but.......the 520 wouldn't give us a reading for some reason. Therefore the RPM is unverified on that boat. Maybe the tach is off causing some of the confusion??

Sorry for the oversight.
Click to expand...

Thank you guys a lot for all the hard work, money, time and effort you guys have put into this. Would I be wrong in saying that the 520 results are not useful until we know whether or not that tach is accurate. My thinking is if he is reading 100 to 150 more than he is spinning (not uncommon) it may very well be like cntry said he is not putting out the same power as the 540. Or if his tach is accurate then we can assume it is somewhere in the airflow restriction. Please correct me if I'm wrong.
 
jre1226 said:
Roxy7430 said:
I have a correction to make:

I stated earlier that we verified the tach on every boat. We did put the digital timing light on every boat but.......the 520 wouldn't give us a reading for some reason. Therefore the RPM is unverified on that boat. Maybe the tach is off causing some of the confusion??

Sorry for the oversight.
Click to expand...

Thank you guys a lot for all the hard work, money, time and effort you guys have put into this. Would I be wrong in saying that the 520 results are not useful until we know whether or not that tach is accurate. My thinking is if he is reading 100 to 150 more than he is spinning (not uncommon) it may very well be like cntry said he is not putting out the same power as the 540. Or if his tach is accurate then we can assume it is somewhere in the airflow restriction. Please correct me if I'm wrong.
Click to expand...


jre We just don't know for sure. We had assumed that the tach was accurate on the 520. Every other boat had an accurate tach.
 
A prop set at the same length and pitch and spun to the same RPM should produce the same numbers across the board IMO no matter what motor it's on. Am I missing something ?
 
fl cracker said:
A prop set at the same length and pitch and spun to the same RPM should produce the same numbers across the board IMO no matter what motor it's on. Am I missing something ?
Click to expand...
Rigging,cage design,and seating arrangement all play a part in the thrust numbers.
 
Pitch marks don't mean much! There is a boat owner on here that swears he is pitched a very strong 3. His buddy looked at his prop and said it was maybe 2 1/2. That is a big difference on the same boat by two different people. Both are convinced they are right.
 
Tony480 said:
fl cracker said:
A prop set at the same length and pitch and spun to the same RPM should produce the same numbers across the board IMO no matter what motor it's on. Am I missing something ?
Click to expand...
Rigging,cage design,and seating arrangement all play a part in the thrust numbers.
Click to expand...

I agree with tony 100% thats why i was hoping they would test the Q on the 540 boat. I know every boat is going to produce different thrust numbers. I was just wanting to see the differents between the 2 props NGH and Q on the same boat just to get a idea which prop produced more thrust.
 
hogdoggin said:
Tony480 said:
fl cracker said:
A prop set at the same length and pitch and spun to the same RPM should produce the same numbers across the board IMO no matter what motor it's on. Am I missing something ?
Click to expand...
Rigging,cage design,and seating arrangement all play a part in the thrust numbers.
Click to expand...

I agree with tony 100% thats why i was hoping they would test the Q on the 540 boat. I know every boat is going to produce different thrust numbers. I was just wanting to see the differents between the 2 props NGH and Q on the same boat just to get a idea which prop produced more thrust.
Click to expand...

If we do anymore testing with the 0540 I can try to squeeze in the Q on it but we really didn't have any plans to retest it. The boat belongs to my dad and he couldn't care less about thrust testing. LOL. He just wants to go fishing and can't understand why we like working on the boats so much.
 
Big Casino said:
Interesting test showing results from a Timing Adjustment
Click to expand...

Am I reading that chart wrong? Looks like you changed timing and pitch at the same time? If so then the timing is really a non-factor. Less pitch=More RPM's and in this case=less thrust. Or am I misreading it?

Changing two things at one time makes analysis really difficult to me.
 
skinny99 said:
Big Casino said:
Interesting test showing results from a Timing Adjustment
Click to expand...

Am I reading that chart wrong? Looks like you changed timing and pitch at the same time? If so then the timing is really a non-factor. Less pitch=More RPM's and in this case=less thrust. Or am I misreading it?

Changing two things at one time makes analysis really difficult to me.
Click to expand...


Skinny, You are correct. It is not a good idea to change 2 things at the same time. The owner of the boat wanted to do it this way and that is what we did. He was not making changes for the purpose of sharing his results publicly.....he just wanted more RPM and wanted to run at 32*. After the test he left the RPM and put timing back to 28*. I don't think this boat will have any more testing done. The owner is very happy with performance and has no intentions on changing anything. If you drove this boat you would know why. On the water it out performs all others by a good margin.
 
You must log in or register to reply here.
Back
Top