Real Time Thrust Tests with Complete Boats

R

Roxy7430

Well-known member
Thrust testing will take place this weekend and we are looking for your input! We will be doing some real-time, on boat, thrust testing and would like to hear your ideas. We will be testing approximately 9 different boats, with a variety of prop and pitch combinations.

We are in no way associated with, working for, or against any manufacture, vendor, and/or distributor of any Airboat product including, boats, motors, props or reduction units. This is purely an informational session and we intend to share results for the benefit of all. The boats and propellers used are the property of the various owners involved. No product endorsements have been accepted and/or will be recommended as a result of our testing.

Our intension is to determine how a particular combination performs and how the performance may change with variations of RPM(pitch), props, etc. All testing will be preformed and data recorded in a standardized, consistent fashion using digital equipment. This will be as real world as possible, with boats setup and rigged as you would ride, hunt, or fish.

We will test for and collect the following information:

-Total weight of boat.
-Thrust @ 1000 RPM increments including WOT (car motors)
-Thrust @ at 500 RPM increments for AC motors
-Different pitch and prop combo’s for many of the boats

Please respond with any suggestions or input prior to testing and we will try to accommodate your requests. We would like suggestions prior to testing as opposed to criticism after testing.

THE TEST BOATS:
Scorpion, 383,(homebuilt) 2:68 (Gear drive), 3 blade R
Scorpion, bored and stroked 351W (homebuilt), 2:67 (Belt Drive), 3 blade R
Scorpion, 496 BBC, 1.91 (Belt Drive), 8 blade Saber
Jimmy White, 427 MAS, SBC, 2:68 (Gear Drive), 4 blade R
Hamant. 500HP Waterthunder, 2:68 (Gear Drive), 3 blade R
Hamant, LS 1(homebuilt), 2:68 (Gear Drive), 3 blade R
Marty Bray, 0-520 Gitsu Conv, 2 blade Q
RiverMaster 1450 0-540 Parallel Valve, 3 blade NGH
Jimmy White, 220 GPU, 74' ww signature

We will post results early in the new year!

Stay tuned!
 
The Jimmy White 220 gpu should have a 70 inch signature instead of a 74 inch. These signature blades work best with 200 to 300 HP range in 70-72-74 inch. From 235 to 265 HP, i use the 72 inch. Just trying to keep the blade attack angle right for the best efficiency.
Chuck
 
[email protected] said:
The Jimmy White 220 gpu should have a 70 inch signature instead of a 74 inch. These signature blades work best with 200 to 300 HP range in 70-72-74 inch. From 235 to 265 HP, i use the 72 inch. Just trying to keep the blade attack angle right for the best efficiency.
Chuck
Click to expand...

Chuck, That boat did have a 70" on it but recently switched hubs to make it a 74". The "seat of the pants" feel was better with the 74 on the ground. We will know for sure which one produces more after this weekend.
 
Thanks poobough, We set the pitch at 2850 rpm's on the trailer. With the 70 inch, they get more snap which is what most ask for. It should be a good test if the pitch is set for static trust at 2850 rpm for the A/C engines.
Thanks, Chuck
 
sweet! you will need to schedual a massage for those sore shoulders after changing all that pitch! :)
the lie detecter will surly breaks some hearts.ha we should start a side pole on what we think each combo wil blow.
 
fl cracker said:
Poo, did you have a chance to run the 2 blade NGH yet?
Click to expand...

Not yet but that is one of the prop configurations that will be tested.

Chuck, I do belive there was a certian amount of snap that was lost but at the time the owner of the boat was solely interested in how well the boat performed on the ground.
 
dantheairboatman said:
sweet! you will need to schedual a massage for those sore shoulders after changing all that pitch! :)
the lie detecter will surly breaks some hearts.ha we should start a side pole on what we think each combo wil blow.
Click to expand...

I think there will be enough hands on that nobody gets to wore out. Hopefully. "Lie Detecter" I like that. I have'nt heard it put that way yet but it will be exactly that.
 
This could be a good thing for everybody. Way to go !

However, I'm not readily understanding how the total weight of boat is going to be relevant to your outcome.

" . . . All testing will be preformed and data recorded in a standardized, consistent fashion using digital equipment. This will be as real world as possible, with boats setup and rigged as you would ride, hunt, or fish.

We will test for and collect the following information:

-Total weight of boat.
-Thrust @ 1000 RPM increments including WOT (car motors)
-Thrust @ at 500 RPM increments for AC motors
-Different pitch and prop combo’s for many of the boats . . .

If you are thrust testing (no matter the frequency of your recordings) while changing pitch and props, how is the weight of the boat relevant? Have you developed a means of recording thrust in real time, underway and on the water? That would be very cool.

Not meaning to be a smart ass, I just want to understand.

With static thrust testing the weight of the hull, the manufacturer, the engine, the gear ratio (or lack of one), or the prop don't make any difference. Thrust is thrust.

Again, not to be a dick . . I just don't see what the new angle is here that you are attempting to accomplish.

Now if it is your intent to compile 400' times, and/or GPS speeds at given RPMS intervals then I could see how all that other information could be usefull in creating a comparative database. If that is the case, I didn't perceive that by what I read.

I didn't see that you made any mention of doing that: only recording weight, thrust, props & pitches. :scratch:

Deano
 
Here are a couple of ideas:

1. How do the S, R, and Saber blades compare on the same boat at different RPMs?

2. How well do the S,R, and Saber blades do when you over pitch or under pitch them?

3. Can you measure torque roll? Would be interesting to compare torque roll of gear boxes and belt drives.

4. How do 2.37 and 2.68 gear boxes compare to each other? Which one will give you better fuel mileage?

5. Compare 2x4 wire to 4x4 wire for the same engine.

6. Does a Water Walker Signature prop on a 540 A/C make 1200 lbs of thrust? I have always wondered if this claim was true.

7. How much does rigging affect thrust? Might be able to remove rigging on a test boat and find out.

8. How do your thrust numbers compare to WT's?
 
Deano said:
However, I'm not readily understanding how the total weight of boat is going to be relevant to your outcome.
]
Not meaning to be a smart ass, I just want to understand.

Again, not to be a dick . . I just don't see what the new angle is here that you are attempting to accomplish.

Now if it is your intent to compile 400' times, and/or GPS speeds at given RPMS intervals then I could see how all that other information could be usefull in creating a comparative database. If that is the case, I didn't perceive that by what I read.

I didn't see that you made any mention of doing that: only recording weight, thrust, props & pitches. :scratch:

Deano
Click to expand...

Deano: There is no angle here, my brother, just real useable information... Our testing will be static in nature and of the complete boat as rigged by the owner to hunt, fish, ride, etc. This will take into account Air Flow restrictions from seat packages, cage wire, water/oil/ice coolers, etc. It will tell the owner how the entire package performs. As for your weight comment, that information is quite important for those that wish to calculate Thrust to Weight Ratios.
 
CarMotorBarge said:
Here are a couple of ideas:

1. How do the S, R, and Saber blades compare on the same boat at different RPMs?

2. How well do the S,R, and Saber blades do when you over pitch or under pitch them?

3. Can you measure torque roll? Would be interesting to compare torque roll of gear boxes and belt drives.

4. How do 2.37 and 2.68 gear boxes compare to each other? Which one will give you better fuel mileage?

5. Compare 2x4 wire to 4x4 wire for the same engine.

6. Does a Water Walker Signature prop on a 540 A/C make 1200 lbs of thrust? I have always wondered if this claim was true.

7. How much does rigging affect thrust? Might be able to remove rigging on a test boat and find out.

8. How do your thrust numbers compare to WT's?
Click to expand...

CMB: Good Stuff....

The list of boats shown are the one participating, a general description, and the current owner's setup. A boat or two may just thrust test as is, most of the boats will test with several different prop combinations. For instance, 2-Q's, 2-NGH's, 3-NGH's and maybe some Sabers will be tested on one boat, set at same "on trailer" RPM rev limit, others will compare R's to Saber's, etc.

Torque Roll could be recorded thru the independent weight sensors - We'll have to dicuss that one...

We already have discussed a plan to compare one particular prop, set at the same pitch, at a set RPM on two of the AC boats. One has 2x4 cage wire and the other has 5x5 cage wire. Were hoping this shows us something different in numbers.

I'll let the "Project Lead" discuss data comparisons to other's ... But i can tell you this, the intent is to provide real usable information to allow everyone to make there own determinations and conclusions.
 
CarMotorBarge said:
Here are a couple of ideas:

1. How do the S, R, and Saber blades compare on the same boat at different RPMs?

2. How well do the S,R, and Saber blades do when you over pitch or under pitch them?

3. Can you measure torque roll? Would be interesting to compare torque roll of gear boxes and belt drives.

4. How do 2.37 and 2.68 gear boxes compare to each other? Which one will give you better fuel mileage?

5. Compare 2x4 wire to 4x4 wire for the same engine.

6. Does a Water Walker Signature prop on a 540 A/C make 1200 lbs of thrust? I have always wondered if this claim was true.

7. How much does rigging affect thrust? Might be able to remove rigging on a test boat and find out.

8. How do your thrust numbers compare to WT's?
Click to expand...

1. We plan to do R and Saber comparison. Really want to do S but may not have one available.
2. We will vary pitch to see if it helps or hurts
3. The weight sensors are placed at the 4 corners and will capture weight transfer (torque roll) We may get to this but will be one of the last things to test.
4. We will not have time to swap boxes. (we do have a 3:38 if time allows)
5. Again no time or lability to swap rigging although we do have 2x2 and 4x4 on different boats
6. We will find out!
7. Will not be removing rigging
8. Will have thrust #'s for 1 Waterthunder

Thank you for your thoughtful post
 
it all sounds good!!! but i do not see any belt drives on the list,do you want or need one to test? im here to lesson or help.thanks
 
While you are testing the AC motors, it would be interesting to see if you ran 100LL vs 93 octane what the results are. I believe 100LL would make more thrust, but it would be nice to have a number on it.

You could also put an IR gun on the heads to see how much hotter the 93 octane runs......

All this "if" the motors would live for a short 93 octane run.... seems like at least the stock GPU could do this.....

Just a thought.
 
All of this sounds interesting. I would definitely recommend that torque roll is one of the data sets that you collect by default. I think that you will find that longer blades will make more thrust, but also more torque roll. Torque roll also contributes to inefficiency of the prop.
 
marsh DooZer said:
it all sounds good!!! but i do not see any belt drives on the list,do you want or need one to test? im here to lesson or help.thanks
Click to expand...

Actually we will have to belt drives. One is a 1.9 and the other is 2.67. Thanks for the offer of help but as of right I think we got it wipped.
 
Roxy7430,

I applaud your effort. :)

I'm looking forward to seeing the results. :cheers:

When you get around to posting the results, please include info / photos of how you made the measurements.

Duane
 
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