Real Time Thrust Tests with Complete Boats

Waterthunder said:
So all the small blocks had 2.68's accept the WaterThunder which had a 2.38. I will say when propped and pitched correctly the 2.68 makes more thrust. There are several issues that effect all this and we have way to much RnD time an money to give it up. But we must be doing something right if a 4 year old 500HP motor with a 2.38 ratio out trusted the other small blocks that had 600HP plus dyno sheets and 2.68 ratios. I wish they would have done one of our 600HP's with a 2.68 I know for a fact our 600HP with a 2.68 on average makes around 400lb's more of thrust then a 500HP with a 2.38.
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At the same RPM?
 
I have a 418 WT with a 2.68 that is ready to test! Is the thrust trailer coming to the Palm Beach show? I was planning to have my boat there. Also my boat will be at GTO the first week of February.
 
Several people have asked about RPM etc. it is coming!! The post said that detailed spreadsheets are on the way.......including RPM.

Just thought u might like some initial numbers.

Also no plans for Palm Beach as of now
 
poobought said:
C1gator said:
Man this is some interesting stuff..I can see where some 2.68 guys might be scratching there heads....Really good info and thank you for sharing it.......
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You aint kidding, It really suprised me. The Water Thunder with the 2.38 showed us all up. But we will be testing that same motor with a 2.68 so we will know the real differance. Wait till you see the cruise numbers with the 2.38 and also the 1.9 belt.

Come on Dave you know your motors better than anybody take a guess what the differance will be between the 2.38 and 2.68. I must admit I hope the 2.68 does a little better.
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I haven't seen any information yet that would make me use a 2.38 instead of a 2.68, but I am anxiously waiting for all of the data. I agree with Whitebear that you can not derive any conclusions from this data without RPMs and pitch settings. Also thanks to the North Florida guys for doing all of this work. I can see how this information can help improve airboating for everybody. :thumbleft: You just need to hurry up with providing the data. This is like a strip tease. Hurry up and take the clothes off already! :lol:
 
Yah man I wanna see some Hooters !

Y'all done a great job, I'm just anxious, not demeaning or putting anyone down in any way.
 
Bare with us guys, I know yall are ready for the data but the way it is being put together takes a little time and Big C has a tight schedule to keep. But it is coming and there is RPM, pitch and I believe Big C is even putting some thrust to weight ratios together. We tried to record every parameter we could think of and had the equipment to do so. If we forgot some please dont hang us just yet. Im sure there will be alot more testing to come.
 
Rpm's at wot does not make a hill of beans here.thrust through out the whole rpm range and max thrust is what makes a diference.who cares if your engine turns more rpm than mine at wot.if mine generates more thrust at a lower rpm than mine is a better set up. Setting your combo at peak performance on thrust is the most important not rpm's.
 
Ya'll killin' me wanting the data!! AND, I Dont blame you... i sent the basic spreadsheet to Roxy, so that he could distribute to the masses just so ya'll could see that were still working.....

I'll try to answer the questions I remember reading:

Yes, Pitch numbers will be reflected in the information
Yes, Prop Tip speeds were calculated to correspond along with thrust for the boats with reduction.
Yes, Engine RPM's were recorded to go along with the thrust numbers at WOT and at Cruise
Yes, I have calculated the Thrust to Weight Coefficient for each boat at both WOT and at Cruise.
Yes, The data can be somewhat considered apples and oranges. But in my opinion its the first time anyone has attempted to test and document data in a very Un-Biased manner, with the sole intent of sharing with the SA Family to help those that want to learn and make decisions for their own rides. I'm sure this wont be the last experiment. I didn't graduate from Rocket Surgery school, but i have stayed at a Holiday Inn Express, so maybe we can pull this off
Yes, Most of the data I have to work with is centered around the "R" blade. Just happened to be what most car motor fellers had on there boats. I will try to illustrate (if one exists) a correlation to thrust numbers, tip speed, and reduction.

And NO Yobee, I'm not upset that PonyTails didnt knock it outta the park. Thats what this whole test was about. Seeing what the combination of a particular motor, prop, rigging, seats, etc and how it performed on that persons boat. Several men, much smarter than me all expected better out of my boat, me included to have shown out a might better. That's the beauty of Statistical analysis. It takes the personalities out of the equation. (well....for the most part LMAO) I came away from the experience with two things to ponder on. Am I flowing enough fuel at WOT, and did was my desire to built the a boat from my old Everglades grass memories/mentality for use up here on the saltwater the right choice. That straight valve 540 is nothing to scoff at. Its a hell of a motor belonging to a hell of a Man!!!. Both boats had 4x4 wire but I choose to rig my boat with side by side seats (to make momma happy) but i put mine up almost a whole seat higher, and i pushed them back much further .. My past told me to push everything as far back as i could. Then i seen some guys up here with cool looking 1x1 wire baskets under there seats now plop my phat arse up ther too......Soooo have i blocked more air flow to my prop for static thrust? I dunno...????. I do know during the test i had my arm back over the top of the carb. I could feel the pressure of the air on my arm. being pulled back toward the prop but i didn't feel that same pressure behind either seat. If I'm lucky enough for an opportunity back up on the trailer, I might remove my seats and test the boat with my big butt out of the way, see what the numbers say. It's a tool fellas.... It dang sure wont help you catch more fish....... But it will teach us more about our airboats (IMHO)

Now, let me get off here... LSU is fixin to whoop up on Bama'

Roxy will have more to publish to ya'll soon enough
 
bondsman said:
Rpm's at wot does not make a hill of beans here.thrust through out the whole rpm range and max thrust is what makes a diference.who cares if your engine turns more rpm than mine at wot.if mine generates more thrust at a lower rpm than mine is a better set up. Setting your combo at peak performance on thrust is the most important not rpm's.
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I guess I missed something, who said more RPMs was always better? In fact my boat made more thrust at 5500 than it did at 6000.
 
poobought said:
bondsman said:
Rpm's at wot does not make a hill of beans here.thrust through out the whole rpm range and max thrust is what makes a diference.who cares if your engine turns more rpm than mine at wot.if mine generates more thrust at a lower rpm than mine is a better set up. Setting your combo at peak performance on thrust is the most important not rpm's.
Click to expand...

I guess I missed something, who said more RPMs was always better? In fact my boat made more thrust at 5500 than it did at 6000.
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Not gearing that comment towards You guys that did the tests. Just those that have drank the mystical cool-aid that same rpm at wot nonsence
 
bondsman said:
poobought said:
bondsman said:
Rpm's at wot does not make a hill of beans here.thrust through out the whole rpm range and max thrust is what makes a diference.who cares if your engine turns more rpm than mine at wot.if mine generates more thrust at a lower rpm than mine is a better set up. Setting your combo at peak performance on thrust is the most important not rpm's.
Click to expand...

I guess I missed something, who said more RPMs was always better? In fact my boat made more thrust at 5500 than it did at 6000.
Click to expand...
Not gearing that comment towards You guys that did the tests. Just those that have drank the mystical cool-aid that same rpm at wot nonsence
Click to expand...


LMAO That is a good one Bonds, heck my peak hsp is 6000 rpm and I prop'd at 5000 to save fuel and give more trust Dave proved that with my old boat had it at 6000 max hsp it pushs better at 5200 just like he said. I be glad when we all get a chance to try our boats on the tester, in the end like they said a tool to test your combo and my hats off to you all.
 
Big Casino, will you be testing your boat with different props? I would just like to see the NGH versus the Q. For me the seat of the pants felt like the Q fell off but that's just me. I have one you can borrow if you want. 72" 3 blade NGH.


Let me know.
Daniel
 
Ill be willing to put my boat on the trailer for testing with 200 HP 4 Banger.I already have ngh and a q to test. Great job big c and the rest of u guys.
 
bondsman said:
Rpm's at wot does not make a hill of beans here.thrust through out the whole rpm range and max thrust is what makes a diference.who cares if your engine turns more rpm than mine at wot.if mine generates more thrust at a lower rpm than mine is a better set up. Setting your combo at peak performance on thrust is the most important not rpm's.
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Bondsman,

Do you own a Caddie? Sounds like it from your comment. People are asking for engine RPMs so that prop RPMs can be calculated. In the end what matters is how fast the prop is swinging and at what pitch. That is how thrust is made.
 
Yes pitch and prop speed that is what makes thrust. But Max rpm does not always make Max thrust. My point was if you set every ones wot rpm the same that is nonsence. Setting to Max efficient thrust is what counts. These guys are doing this and playing with pitch and rpm.so there test data is more relevant.
 
I want to test my geared a/ c. And my buddy's on there. We made 1000 pounds on our thrust test gauge with 2 blade R .like to see the difference.
 
Since the spreadsheets aren't quite ready yet here is a little more. Most curiosity seems to be about RPM so here goes. (Again, these aren't necessarily the best RPM for max thrust). This is RPM that each boat was set at for normal usage on the first pull. Some of us tried different RPM later on and we experienced improvements (and) declines depending on the boat. What we did determine was that the thrust testing was a very useful tool in pitch selection for cruise thrust and WOT performance. RMP was verified with digital timing light for each boat.

BOAT RPM @ WOT
A (383) 5600
B ("351") 5350
C (496) 4800
D (427) 5000
E (LS1) 5200
F (220) 2800
G (6.2W/T) 5050
H (520) 2800
I (540) 2800
 
Looks like 2000 RPM is the sweet spot for the 3 blade R. Seems to drop off pretty quick over or under that.
 
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